Move client-specific SSH code into new files.
This is a major code reorganisation in preparation for making this
code base into one that can build an SSH server as well as a client.
(Mostly for purposes of using the server as a regression test suite
for the client, though I have some other possible uses in mind too.
However, it's currently no part of my plan to harden the server to the
point where it can sensibly be deployed in a hostile environment.)
In this preparatory commit, I've broken up the SSH-2 transport and
connection layers, and the SSH-1 connection layer, into multiple
source files, with each layer having its own header file containing
the shared type definitions. In each case, the new source file
contains code that's specific to the client side of the protocol, so
that a new file can be swapped in in its place when building the
server.
Mostly this is just a straightforward moving of code without changing
it very much, but there are a couple of actual changes in the process:
The parsing of SSH-2 global-request and channel open-messages is now
done by a new pair of functions in the client module. For channel
opens, I've invented a new union data type to be the return value from
that function, representing either failure (plus error message),
success (plus Channel instance to manage the new channel), or an
instruction to hand the channel over to a sharing downstream (plus a
pointer to the downstream in question).
Also, the tree234 of remote port forwardings in ssh2connection is now
initialised on first use by the client-specific code, so that's where
its compare function lives. The shared ssh2connection_free() still
takes responsibility for freeing it, but now has to check if it's
non-null first.
The outer shell of the ssh2_lportfwd_open method, for making a
local-to-remote port forwarding, is still centralised in
ssh2connection.c, but the part of it that actually constructs the
outgoing channel-open message has moved into the client code, because
that will have to change depending on whether the channel-open has to
have type direct-tcpip or forwarded-tcpip.
In the SSH-1 connection layer, half the filter_queue method has moved
out into the new client-specific code, but not all of it -
bidirectional channel maintenance messages are still handled
centrally. One exception is SSH_MSG_PORT_OPEN, which can be sent in
both directions, but with subtly different semantics - from server to
client, it's referring to a previously established remote forwarding
(and must be rejected if there isn't one that matches it), but from
client to server it's just a "direct-tcpip" request with no prior
context. So that one is in the client-specific module, and when I add
the server code it will have its own different handler.
2018-10-20 19:57:37 +03:00
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/*
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* Header connecting the pieces of the SSH-2 transport layer.
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*/
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#ifndef PUTTY_SSH2TRANSPORT_H
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#define PUTTY_SSH2TRANSPORT_H
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#ifndef NO_GSSAPI
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#include "sshgssc.h"
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#include "sshgss.h"
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#define MIN_CTXT_LIFETIME 5 /* Avoid rekey with short lifetime (seconds) */
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#define GSS_KEX_CAPABLE (1<<0) /* Can do GSS KEX */
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#define GSS_CRED_UPDATED (1<<1) /* Cred updated since previous delegation */
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#define GSS_CTXT_EXPIRES (1<<2) /* Context expires before next timer */
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#define GSS_CTXT_MAYFAIL (1<<3) /* Context may expire during handshake */
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#endif
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#define DH_MIN_SIZE 1024
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#define DH_MAX_SIZE 8192
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enum kexlist {
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KEXLIST_KEX, KEXLIST_HOSTKEY, KEXLIST_CSCIPHER, KEXLIST_SCCIPHER,
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KEXLIST_CSMAC, KEXLIST_SCMAC, KEXLIST_CSCOMP, KEXLIST_SCCOMP,
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NKEXLIST
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};
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#define MAXKEXLIST 16
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struct kexinit_algorithm {
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const char *name;
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union {
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struct {
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const struct ssh_kex *kex;
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Convert a lot of 'int' variables to 'bool'.
My normal habit these days, in new code, is to treat int and bool as
_almost_ completely separate types. I'm still willing to use C's
implicit test for zero on an integer (e.g. 'if (!blob.len)' is fine,
no need to spell it out as blob.len != 0), but generally, if a
variable is going to be conceptually a boolean, I like to declare it
bool and assign to it using 'true' or 'false' rather than 0 or 1.
PuTTY is an exception, because it predates the C99 bool, and I've
stuck to its existing coding style even when adding new code to it.
But it's been annoying me more and more, so now that I've decided C99
bool is an acceptable thing to require from our toolchain in the first
place, here's a quite thorough trawl through the source doing
'boolification'. Many variables and function parameters are now typed
as bool rather than int; many assignments of 0 or 1 to those variables
are now spelled 'true' or 'false'.
I managed this thorough conversion with the help of a custom clang
plugin that I wrote to trawl the AST and apply heuristics to point out
where things might want changing. So I've even managed to do a decent
job on parts of the code I haven't looked at in years!
To make the plugin's work easier, I pushed platform front ends
generally in the direction of using standard 'bool' in preference to
platform-specific boolean types like Windows BOOL or GTK's gboolean;
I've left the platform booleans in places they _have_ to be for the
platform APIs to work right, but variables only used by my own code
have been converted wherever I found them.
In a few places there are int values that look very like booleans in
_most_ of the places they're used, but have a rarely-used third value,
or a distinction between different nonzero values that most users
don't care about. In these cases, I've _removed_ uses of 'true' and
'false' for the return values, to emphasise that there's something
more subtle going on than a simple boolean answer:
- the 'multisel' field in dialog.h's list box structure, for which
the GTK front end in particular recognises a difference between 1
and 2 but nearly everything else treats as boolean
- the 'urgent' parameter to plug_receive, where 1 vs 2 tells you
something about the specific location of the urgent pointer, but
most clients only care about 0 vs 'something nonzero'
- the return value of wc_match, where -1 indicates a syntax error in
the wildcard.
- the return values from SSH-1 RSA-key loading functions, which use
-1 for 'wrong passphrase' and 0 for all other failures (so any
caller which already knows it's not loading an _encrypted private_
key can treat them as boolean)
- term->esc_query, and the 'query' parameter in toggle_mode in
terminal.c, which _usually_ hold 0 for ESC[123h or 1 for ESC[?123h,
but can also hold -1 for some other intervening character that we
don't support.
In a few places there's an integer that I haven't turned into a bool
even though it really _can_ only take values 0 or 1 (and, as above,
tried to make the call sites consistent in not calling those values
true and false), on the grounds that I thought it would make it more
confusing to imply that the 0 value was in some sense 'negative' or
bad and the 1 positive or good:
- the return value of plug_accepting uses the POSIXish convention of
0=success and nonzero=error; I think if I made it bool then I'd
also want to reverse its sense, and that's a job for a separate
piece of work.
- the 'screen' parameter to lineptr() in terminal.c, where 0 and 1
represent the default and alternate screens. There's no obvious
reason why one of those should be considered 'true' or 'positive'
or 'success' - they're just indices - so I've left it as int.
ssh_scp_recv had particularly confusing semantics for its previous int
return value: its call sites used '<= 0' to check for error, but it
never actually returned a negative number, just 0 or 1. Now the
function and its call sites agree that it's a bool.
In a couple of places I've renamed variables called 'ret', because I
don't like that name any more - it's unclear whether it means the
return value (in preparation) for the _containing_ function or the
return value received from a subroutine call, and occasionally I've
accidentally used the same variable for both and introduced a bug. So
where one of those got in my way, I've renamed it to 'toret' or 'retd'
(the latter short for 'returned') in line with my usual modern
practice, but I haven't done a thorough job of finding all of them.
Finally, one amusing side effect of doing this is that I've had to
separate quite a few chained assignments. It used to be perfectly fine
to write 'a = b = c = TRUE' when a,b,c were int and TRUE was just a
the 'true' defined by stdbool.h, that idiom provokes a warning from
gcc: 'suggest parentheses around assignment used as truth value'!
2018-11-02 22:23:19 +03:00
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|
|
bool warn;
|
Move client-specific SSH code into new files.
This is a major code reorganisation in preparation for making this
code base into one that can build an SSH server as well as a client.
(Mostly for purposes of using the server as a regression test suite
for the client, though I have some other possible uses in mind too.
However, it's currently no part of my plan to harden the server to the
point where it can sensibly be deployed in a hostile environment.)
In this preparatory commit, I've broken up the SSH-2 transport and
connection layers, and the SSH-1 connection layer, into multiple
source files, with each layer having its own header file containing
the shared type definitions. In each case, the new source file
contains code that's specific to the client side of the protocol, so
that a new file can be swapped in in its place when building the
server.
Mostly this is just a straightforward moving of code without changing
it very much, but there are a couple of actual changes in the process:
The parsing of SSH-2 global-request and channel open-messages is now
done by a new pair of functions in the client module. For channel
opens, I've invented a new union data type to be the return value from
that function, representing either failure (plus error message),
success (plus Channel instance to manage the new channel), or an
instruction to hand the channel over to a sharing downstream (plus a
pointer to the downstream in question).
Also, the tree234 of remote port forwardings in ssh2connection is now
initialised on first use by the client-specific code, so that's where
its compare function lives. The shared ssh2connection_free() still
takes responsibility for freeing it, but now has to check if it's
non-null first.
The outer shell of the ssh2_lportfwd_open method, for making a
local-to-remote port forwarding, is still centralised in
ssh2connection.c, but the part of it that actually constructs the
outgoing channel-open message has moved into the client code, because
that will have to change depending on whether the channel-open has to
have type direct-tcpip or forwarded-tcpip.
In the SSH-1 connection layer, half the filter_queue method has moved
out into the new client-specific code, but not all of it -
bidirectional channel maintenance messages are still handled
centrally. One exception is SSH_MSG_PORT_OPEN, which can be sent in
both directions, but with subtly different semantics - from server to
client, it's referring to a previously established remote forwarding
(and must be rejected if there isn't one that matches it), but from
client to server it's just a "direct-tcpip" request with no prior
context. So that one is in the client-specific module, and when I add
the server code it will have its own different handler.
2018-10-20 19:57:37 +03:00
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} kex;
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struct {
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const ssh_keyalg *hostkey;
|
Convert a lot of 'int' variables to 'bool'.
My normal habit these days, in new code, is to treat int and bool as
_almost_ completely separate types. I'm still willing to use C's
implicit test for zero on an integer (e.g. 'if (!blob.len)' is fine,
no need to spell it out as blob.len != 0), but generally, if a
variable is going to be conceptually a boolean, I like to declare it
bool and assign to it using 'true' or 'false' rather than 0 or 1.
PuTTY is an exception, because it predates the C99 bool, and I've
stuck to its existing coding style even when adding new code to it.
But it's been annoying me more and more, so now that I've decided C99
bool is an acceptable thing to require from our toolchain in the first
place, here's a quite thorough trawl through the source doing
'boolification'. Many variables and function parameters are now typed
as bool rather than int; many assignments of 0 or 1 to those variables
are now spelled 'true' or 'false'.
I managed this thorough conversion with the help of a custom clang
plugin that I wrote to trawl the AST and apply heuristics to point out
where things might want changing. So I've even managed to do a decent
job on parts of the code I haven't looked at in years!
To make the plugin's work easier, I pushed platform front ends
generally in the direction of using standard 'bool' in preference to
platform-specific boolean types like Windows BOOL or GTK's gboolean;
I've left the platform booleans in places they _have_ to be for the
platform APIs to work right, but variables only used by my own code
have been converted wherever I found them.
In a few places there are int values that look very like booleans in
_most_ of the places they're used, but have a rarely-used third value,
or a distinction between different nonzero values that most users
don't care about. In these cases, I've _removed_ uses of 'true' and
'false' for the return values, to emphasise that there's something
more subtle going on than a simple boolean answer:
- the 'multisel' field in dialog.h's list box structure, for which
the GTK front end in particular recognises a difference between 1
and 2 but nearly everything else treats as boolean
- the 'urgent' parameter to plug_receive, where 1 vs 2 tells you
something about the specific location of the urgent pointer, but
most clients only care about 0 vs 'something nonzero'
- the return value of wc_match, where -1 indicates a syntax error in
the wildcard.
- the return values from SSH-1 RSA-key loading functions, which use
-1 for 'wrong passphrase' and 0 for all other failures (so any
caller which already knows it's not loading an _encrypted private_
key can treat them as boolean)
- term->esc_query, and the 'query' parameter in toggle_mode in
terminal.c, which _usually_ hold 0 for ESC[123h or 1 for ESC[?123h,
but can also hold -1 for some other intervening character that we
don't support.
In a few places there's an integer that I haven't turned into a bool
even though it really _can_ only take values 0 or 1 (and, as above,
tried to make the call sites consistent in not calling those values
true and false), on the grounds that I thought it would make it more
confusing to imply that the 0 value was in some sense 'negative' or
bad and the 1 positive or good:
- the return value of plug_accepting uses the POSIXish convention of
0=success and nonzero=error; I think if I made it bool then I'd
also want to reverse its sense, and that's a job for a separate
piece of work.
- the 'screen' parameter to lineptr() in terminal.c, where 0 and 1
represent the default and alternate screens. There's no obvious
reason why one of those should be considered 'true' or 'positive'
or 'success' - they're just indices - so I've left it as int.
ssh_scp_recv had particularly confusing semantics for its previous int
return value: its call sites used '<= 0' to check for error, but it
never actually returned a negative number, just 0 or 1. Now the
function and its call sites agree that it's a bool.
In a couple of places I've renamed variables called 'ret', because I
don't like that name any more - it's unclear whether it means the
return value (in preparation) for the _containing_ function or the
return value received from a subroutine call, and occasionally I've
accidentally used the same variable for both and introduced a bug. So
where one of those got in my way, I've renamed it to 'toret' or 'retd'
(the latter short for 'returned') in line with my usual modern
practice, but I haven't done a thorough job of finding all of them.
Finally, one amusing side effect of doing this is that I've had to
separate quite a few chained assignments. It used to be perfectly fine
to write 'a = b = c = TRUE' when a,b,c were int and TRUE was just a
the 'true' defined by stdbool.h, that idiom provokes a warning from
gcc: 'suggest parentheses around assignment used as truth value'!
2018-11-02 22:23:19 +03:00
|
|
|
bool warn;
|
Move client-specific SSH code into new files.
This is a major code reorganisation in preparation for making this
code base into one that can build an SSH server as well as a client.
(Mostly for purposes of using the server as a regression test suite
for the client, though I have some other possible uses in mind too.
However, it's currently no part of my plan to harden the server to the
point where it can sensibly be deployed in a hostile environment.)
In this preparatory commit, I've broken up the SSH-2 transport and
connection layers, and the SSH-1 connection layer, into multiple
source files, with each layer having its own header file containing
the shared type definitions. In each case, the new source file
contains code that's specific to the client side of the protocol, so
that a new file can be swapped in in its place when building the
server.
Mostly this is just a straightforward moving of code without changing
it very much, but there are a couple of actual changes in the process:
The parsing of SSH-2 global-request and channel open-messages is now
done by a new pair of functions in the client module. For channel
opens, I've invented a new union data type to be the return value from
that function, representing either failure (plus error message),
success (plus Channel instance to manage the new channel), or an
instruction to hand the channel over to a sharing downstream (plus a
pointer to the downstream in question).
Also, the tree234 of remote port forwardings in ssh2connection is now
initialised on first use by the client-specific code, so that's where
its compare function lives. The shared ssh2connection_free() still
takes responsibility for freeing it, but now has to check if it's
non-null first.
The outer shell of the ssh2_lportfwd_open method, for making a
local-to-remote port forwarding, is still centralised in
ssh2connection.c, but the part of it that actually constructs the
outgoing channel-open message has moved into the client code, because
that will have to change depending on whether the channel-open has to
have type direct-tcpip or forwarded-tcpip.
In the SSH-1 connection layer, half the filter_queue method has moved
out into the new client-specific code, but not all of it -
bidirectional channel maintenance messages are still handled
centrally. One exception is SSH_MSG_PORT_OPEN, which can be sent in
both directions, but with subtly different semantics - from server to
client, it's referring to a previously established remote forwarding
(and must be rejected if there isn't one that matches it), but from
client to server it's just a "direct-tcpip" request with no prior
context. So that one is in the client-specific module, and when I add
the server code it will have its own different handler.
2018-10-20 19:57:37 +03:00
|
|
|
} hk;
|
|
|
|
struct {
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|
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const struct ssh2_cipheralg *cipher;
|
Convert a lot of 'int' variables to 'bool'.
My normal habit these days, in new code, is to treat int and bool as
_almost_ completely separate types. I'm still willing to use C's
implicit test for zero on an integer (e.g. 'if (!blob.len)' is fine,
no need to spell it out as blob.len != 0), but generally, if a
variable is going to be conceptually a boolean, I like to declare it
bool and assign to it using 'true' or 'false' rather than 0 or 1.
PuTTY is an exception, because it predates the C99 bool, and I've
stuck to its existing coding style even when adding new code to it.
But it's been annoying me more and more, so now that I've decided C99
bool is an acceptable thing to require from our toolchain in the first
place, here's a quite thorough trawl through the source doing
'boolification'. Many variables and function parameters are now typed
as bool rather than int; many assignments of 0 or 1 to those variables
are now spelled 'true' or 'false'.
I managed this thorough conversion with the help of a custom clang
plugin that I wrote to trawl the AST and apply heuristics to point out
where things might want changing. So I've even managed to do a decent
job on parts of the code I haven't looked at in years!
To make the plugin's work easier, I pushed platform front ends
generally in the direction of using standard 'bool' in preference to
platform-specific boolean types like Windows BOOL or GTK's gboolean;
I've left the platform booleans in places they _have_ to be for the
platform APIs to work right, but variables only used by my own code
have been converted wherever I found them.
In a few places there are int values that look very like booleans in
_most_ of the places they're used, but have a rarely-used third value,
or a distinction between different nonzero values that most users
don't care about. In these cases, I've _removed_ uses of 'true' and
'false' for the return values, to emphasise that there's something
more subtle going on than a simple boolean answer:
- the 'multisel' field in dialog.h's list box structure, for which
the GTK front end in particular recognises a difference between 1
and 2 but nearly everything else treats as boolean
- the 'urgent' parameter to plug_receive, where 1 vs 2 tells you
something about the specific location of the urgent pointer, but
most clients only care about 0 vs 'something nonzero'
- the return value of wc_match, where -1 indicates a syntax error in
the wildcard.
- the return values from SSH-1 RSA-key loading functions, which use
-1 for 'wrong passphrase' and 0 for all other failures (so any
caller which already knows it's not loading an _encrypted private_
key can treat them as boolean)
- term->esc_query, and the 'query' parameter in toggle_mode in
terminal.c, which _usually_ hold 0 for ESC[123h or 1 for ESC[?123h,
but can also hold -1 for some other intervening character that we
don't support.
In a few places there's an integer that I haven't turned into a bool
even though it really _can_ only take values 0 or 1 (and, as above,
tried to make the call sites consistent in not calling those values
true and false), on the grounds that I thought it would make it more
confusing to imply that the 0 value was in some sense 'negative' or
bad and the 1 positive or good:
- the return value of plug_accepting uses the POSIXish convention of
0=success and nonzero=error; I think if I made it bool then I'd
also want to reverse its sense, and that's a job for a separate
piece of work.
- the 'screen' parameter to lineptr() in terminal.c, where 0 and 1
represent the default and alternate screens. There's no obvious
reason why one of those should be considered 'true' or 'positive'
or 'success' - they're just indices - so I've left it as int.
ssh_scp_recv had particularly confusing semantics for its previous int
return value: its call sites used '<= 0' to check for error, but it
never actually returned a negative number, just 0 or 1. Now the
function and its call sites agree that it's a bool.
In a couple of places I've renamed variables called 'ret', because I
don't like that name any more - it's unclear whether it means the
return value (in preparation) for the _containing_ function or the
return value received from a subroutine call, and occasionally I've
accidentally used the same variable for both and introduced a bug. So
where one of those got in my way, I've renamed it to 'toret' or 'retd'
(the latter short for 'returned') in line with my usual modern
practice, but I haven't done a thorough job of finding all of them.
Finally, one amusing side effect of doing this is that I've had to
separate quite a few chained assignments. It used to be perfectly fine
to write 'a = b = c = TRUE' when a,b,c were int and TRUE was just a
the 'true' defined by stdbool.h, that idiom provokes a warning from
gcc: 'suggest parentheses around assignment used as truth value'!
2018-11-02 22:23:19 +03:00
|
|
|
bool warn;
|
Move client-specific SSH code into new files.
This is a major code reorganisation in preparation for making this
code base into one that can build an SSH server as well as a client.
(Mostly for purposes of using the server as a regression test suite
for the client, though I have some other possible uses in mind too.
However, it's currently no part of my plan to harden the server to the
point where it can sensibly be deployed in a hostile environment.)
In this preparatory commit, I've broken up the SSH-2 transport and
connection layers, and the SSH-1 connection layer, into multiple
source files, with each layer having its own header file containing
the shared type definitions. In each case, the new source file
contains code that's specific to the client side of the protocol, so
that a new file can be swapped in in its place when building the
server.
Mostly this is just a straightforward moving of code without changing
it very much, but there are a couple of actual changes in the process:
The parsing of SSH-2 global-request and channel open-messages is now
done by a new pair of functions in the client module. For channel
opens, I've invented a new union data type to be the return value from
that function, representing either failure (plus error message),
success (plus Channel instance to manage the new channel), or an
instruction to hand the channel over to a sharing downstream (plus a
pointer to the downstream in question).
Also, the tree234 of remote port forwardings in ssh2connection is now
initialised on first use by the client-specific code, so that's where
its compare function lives. The shared ssh2connection_free() still
takes responsibility for freeing it, but now has to check if it's
non-null first.
The outer shell of the ssh2_lportfwd_open method, for making a
local-to-remote port forwarding, is still centralised in
ssh2connection.c, but the part of it that actually constructs the
outgoing channel-open message has moved into the client code, because
that will have to change depending on whether the channel-open has to
have type direct-tcpip or forwarded-tcpip.
In the SSH-1 connection layer, half the filter_queue method has moved
out into the new client-specific code, but not all of it -
bidirectional channel maintenance messages are still handled
centrally. One exception is SSH_MSG_PORT_OPEN, which can be sent in
both directions, but with subtly different semantics - from server to
client, it's referring to a previously established remote forwarding
(and must be rejected if there isn't one that matches it), but from
client to server it's just a "direct-tcpip" request with no prior
context. So that one is in the client-specific module, and when I add
the server code it will have its own different handler.
2018-10-20 19:57:37 +03:00
|
|
|
} cipher;
|
|
|
|
struct {
|
|
|
|
const struct ssh2_macalg *mac;
|
Convert a lot of 'int' variables to 'bool'.
My normal habit these days, in new code, is to treat int and bool as
_almost_ completely separate types. I'm still willing to use C's
implicit test for zero on an integer (e.g. 'if (!blob.len)' is fine,
no need to spell it out as blob.len != 0), but generally, if a
variable is going to be conceptually a boolean, I like to declare it
bool and assign to it using 'true' or 'false' rather than 0 or 1.
PuTTY is an exception, because it predates the C99 bool, and I've
stuck to its existing coding style even when adding new code to it.
But it's been annoying me more and more, so now that I've decided C99
bool is an acceptable thing to require from our toolchain in the first
place, here's a quite thorough trawl through the source doing
'boolification'. Many variables and function parameters are now typed
as bool rather than int; many assignments of 0 or 1 to those variables
are now spelled 'true' or 'false'.
I managed this thorough conversion with the help of a custom clang
plugin that I wrote to trawl the AST and apply heuristics to point out
where things might want changing. So I've even managed to do a decent
job on parts of the code I haven't looked at in years!
To make the plugin's work easier, I pushed platform front ends
generally in the direction of using standard 'bool' in preference to
platform-specific boolean types like Windows BOOL or GTK's gboolean;
I've left the platform booleans in places they _have_ to be for the
platform APIs to work right, but variables only used by my own code
have been converted wherever I found them.
In a few places there are int values that look very like booleans in
_most_ of the places they're used, but have a rarely-used third value,
or a distinction between different nonzero values that most users
don't care about. In these cases, I've _removed_ uses of 'true' and
'false' for the return values, to emphasise that there's something
more subtle going on than a simple boolean answer:
- the 'multisel' field in dialog.h's list box structure, for which
the GTK front end in particular recognises a difference between 1
and 2 but nearly everything else treats as boolean
- the 'urgent' parameter to plug_receive, where 1 vs 2 tells you
something about the specific location of the urgent pointer, but
most clients only care about 0 vs 'something nonzero'
- the return value of wc_match, where -1 indicates a syntax error in
the wildcard.
- the return values from SSH-1 RSA-key loading functions, which use
-1 for 'wrong passphrase' and 0 for all other failures (so any
caller which already knows it's not loading an _encrypted private_
key can treat them as boolean)
- term->esc_query, and the 'query' parameter in toggle_mode in
terminal.c, which _usually_ hold 0 for ESC[123h or 1 for ESC[?123h,
but can also hold -1 for some other intervening character that we
don't support.
In a few places there's an integer that I haven't turned into a bool
even though it really _can_ only take values 0 or 1 (and, as above,
tried to make the call sites consistent in not calling those values
true and false), on the grounds that I thought it would make it more
confusing to imply that the 0 value was in some sense 'negative' or
bad and the 1 positive or good:
- the return value of plug_accepting uses the POSIXish convention of
0=success and nonzero=error; I think if I made it bool then I'd
also want to reverse its sense, and that's a job for a separate
piece of work.
- the 'screen' parameter to lineptr() in terminal.c, where 0 and 1
represent the default and alternate screens. There's no obvious
reason why one of those should be considered 'true' or 'positive'
or 'success' - they're just indices - so I've left it as int.
ssh_scp_recv had particularly confusing semantics for its previous int
return value: its call sites used '<= 0' to check for error, but it
never actually returned a negative number, just 0 or 1. Now the
function and its call sites agree that it's a bool.
In a couple of places I've renamed variables called 'ret', because I
don't like that name any more - it's unclear whether it means the
return value (in preparation) for the _containing_ function or the
return value received from a subroutine call, and occasionally I've
accidentally used the same variable for both and introduced a bug. So
where one of those got in my way, I've renamed it to 'toret' or 'retd'
(the latter short for 'returned') in line with my usual modern
practice, but I haven't done a thorough job of finding all of them.
Finally, one amusing side effect of doing this is that I've had to
separate quite a few chained assignments. It used to be perfectly fine
to write 'a = b = c = TRUE' when a,b,c were int and TRUE was just a
the 'true' defined by stdbool.h, that idiom provokes a warning from
gcc: 'suggest parentheses around assignment used as truth value'!
2018-11-02 22:23:19 +03:00
|
|
|
bool etm;
|
Move client-specific SSH code into new files.
This is a major code reorganisation in preparation for making this
code base into one that can build an SSH server as well as a client.
(Mostly for purposes of using the server as a regression test suite
for the client, though I have some other possible uses in mind too.
However, it's currently no part of my plan to harden the server to the
point where it can sensibly be deployed in a hostile environment.)
In this preparatory commit, I've broken up the SSH-2 transport and
connection layers, and the SSH-1 connection layer, into multiple
source files, with each layer having its own header file containing
the shared type definitions. In each case, the new source file
contains code that's specific to the client side of the protocol, so
that a new file can be swapped in in its place when building the
server.
Mostly this is just a straightforward moving of code without changing
it very much, but there are a couple of actual changes in the process:
The parsing of SSH-2 global-request and channel open-messages is now
done by a new pair of functions in the client module. For channel
opens, I've invented a new union data type to be the return value from
that function, representing either failure (plus error message),
success (plus Channel instance to manage the new channel), or an
instruction to hand the channel over to a sharing downstream (plus a
pointer to the downstream in question).
Also, the tree234 of remote port forwardings in ssh2connection is now
initialised on first use by the client-specific code, so that's where
its compare function lives. The shared ssh2connection_free() still
takes responsibility for freeing it, but now has to check if it's
non-null first.
The outer shell of the ssh2_lportfwd_open method, for making a
local-to-remote port forwarding, is still centralised in
ssh2connection.c, but the part of it that actually constructs the
outgoing channel-open message has moved into the client code, because
that will have to change depending on whether the channel-open has to
have type direct-tcpip or forwarded-tcpip.
In the SSH-1 connection layer, half the filter_queue method has moved
out into the new client-specific code, but not all of it -
bidirectional channel maintenance messages are still handled
centrally. One exception is SSH_MSG_PORT_OPEN, which can be sent in
both directions, but with subtly different semantics - from server to
client, it's referring to a previously established remote forwarding
(and must be rejected if there isn't one that matches it), but from
client to server it's just a "direct-tcpip" request with no prior
context. So that one is in the client-specific module, and when I add
the server code it will have its own different handler.
2018-10-20 19:57:37 +03:00
|
|
|
} mac;
|
|
|
|
struct {
|
|
|
|
const struct ssh_compression_alg *comp;
|
Convert a lot of 'int' variables to 'bool'.
My normal habit these days, in new code, is to treat int and bool as
_almost_ completely separate types. I'm still willing to use C's
implicit test for zero on an integer (e.g. 'if (!blob.len)' is fine,
no need to spell it out as blob.len != 0), but generally, if a
variable is going to be conceptually a boolean, I like to declare it
bool and assign to it using 'true' or 'false' rather than 0 or 1.
PuTTY is an exception, because it predates the C99 bool, and I've
stuck to its existing coding style even when adding new code to it.
But it's been annoying me more and more, so now that I've decided C99
bool is an acceptable thing to require from our toolchain in the first
place, here's a quite thorough trawl through the source doing
'boolification'. Many variables and function parameters are now typed
as bool rather than int; many assignments of 0 or 1 to those variables
are now spelled 'true' or 'false'.
I managed this thorough conversion with the help of a custom clang
plugin that I wrote to trawl the AST and apply heuristics to point out
where things might want changing. So I've even managed to do a decent
job on parts of the code I haven't looked at in years!
To make the plugin's work easier, I pushed platform front ends
generally in the direction of using standard 'bool' in preference to
platform-specific boolean types like Windows BOOL or GTK's gboolean;
I've left the platform booleans in places they _have_ to be for the
platform APIs to work right, but variables only used by my own code
have been converted wherever I found them.
In a few places there are int values that look very like booleans in
_most_ of the places they're used, but have a rarely-used third value,
or a distinction between different nonzero values that most users
don't care about. In these cases, I've _removed_ uses of 'true' and
'false' for the return values, to emphasise that there's something
more subtle going on than a simple boolean answer:
- the 'multisel' field in dialog.h's list box structure, for which
the GTK front end in particular recognises a difference between 1
and 2 but nearly everything else treats as boolean
- the 'urgent' parameter to plug_receive, where 1 vs 2 tells you
something about the specific location of the urgent pointer, but
most clients only care about 0 vs 'something nonzero'
- the return value of wc_match, where -1 indicates a syntax error in
the wildcard.
- the return values from SSH-1 RSA-key loading functions, which use
-1 for 'wrong passphrase' and 0 for all other failures (so any
caller which already knows it's not loading an _encrypted private_
key can treat them as boolean)
- term->esc_query, and the 'query' parameter in toggle_mode in
terminal.c, which _usually_ hold 0 for ESC[123h or 1 for ESC[?123h,
but can also hold -1 for some other intervening character that we
don't support.
In a few places there's an integer that I haven't turned into a bool
even though it really _can_ only take values 0 or 1 (and, as above,
tried to make the call sites consistent in not calling those values
true and false), on the grounds that I thought it would make it more
confusing to imply that the 0 value was in some sense 'negative' or
bad and the 1 positive or good:
- the return value of plug_accepting uses the POSIXish convention of
0=success and nonzero=error; I think if I made it bool then I'd
also want to reverse its sense, and that's a job for a separate
piece of work.
- the 'screen' parameter to lineptr() in terminal.c, where 0 and 1
represent the default and alternate screens. There's no obvious
reason why one of those should be considered 'true' or 'positive'
or 'success' - they're just indices - so I've left it as int.
ssh_scp_recv had particularly confusing semantics for its previous int
return value: its call sites used '<= 0' to check for error, but it
never actually returned a negative number, just 0 or 1. Now the
function and its call sites agree that it's a bool.
In a couple of places I've renamed variables called 'ret', because I
don't like that name any more - it's unclear whether it means the
return value (in preparation) for the _containing_ function or the
return value received from a subroutine call, and occasionally I've
accidentally used the same variable for both and introduced a bug. So
where one of those got in my way, I've renamed it to 'toret' or 'retd'
(the latter short for 'returned') in line with my usual modern
practice, but I haven't done a thorough job of finding all of them.
Finally, one amusing side effect of doing this is that I've had to
separate quite a few chained assignments. It used to be perfectly fine
to write 'a = b = c = TRUE' when a,b,c were int and TRUE was just a
the 'true' defined by stdbool.h, that idiom provokes a warning from
gcc: 'suggest parentheses around assignment used as truth value'!
2018-11-02 22:23:19 +03:00
|
|
|
bool delayed;
|
Move client-specific SSH code into new files.
This is a major code reorganisation in preparation for making this
code base into one that can build an SSH server as well as a client.
(Mostly for purposes of using the server as a regression test suite
for the client, though I have some other possible uses in mind too.
However, it's currently no part of my plan to harden the server to the
point where it can sensibly be deployed in a hostile environment.)
In this preparatory commit, I've broken up the SSH-2 transport and
connection layers, and the SSH-1 connection layer, into multiple
source files, with each layer having its own header file containing
the shared type definitions. In each case, the new source file
contains code that's specific to the client side of the protocol, so
that a new file can be swapped in in its place when building the
server.
Mostly this is just a straightforward moving of code without changing
it very much, but there are a couple of actual changes in the process:
The parsing of SSH-2 global-request and channel open-messages is now
done by a new pair of functions in the client module. For channel
opens, I've invented a new union data type to be the return value from
that function, representing either failure (plus error message),
success (plus Channel instance to manage the new channel), or an
instruction to hand the channel over to a sharing downstream (plus a
pointer to the downstream in question).
Also, the tree234 of remote port forwardings in ssh2connection is now
initialised on first use by the client-specific code, so that's where
its compare function lives. The shared ssh2connection_free() still
takes responsibility for freeing it, but now has to check if it's
non-null first.
The outer shell of the ssh2_lportfwd_open method, for making a
local-to-remote port forwarding, is still centralised in
ssh2connection.c, but the part of it that actually constructs the
outgoing channel-open message has moved into the client code, because
that will have to change depending on whether the channel-open has to
have type direct-tcpip or forwarded-tcpip.
In the SSH-1 connection layer, half the filter_queue method has moved
out into the new client-specific code, but not all of it -
bidirectional channel maintenance messages are still handled
centrally. One exception is SSH_MSG_PORT_OPEN, which can be sent in
both directions, but with subtly different semantics - from server to
client, it's referring to a previously established remote forwarding
(and must be rejected if there isn't one that matches it), but from
client to server it's just a "direct-tcpip" request with no prior
context. So that one is in the client-specific module, and when I add
the server code it will have its own different handler.
2018-10-20 19:57:37 +03:00
|
|
|
} comp;
|
|
|
|
} u;
|
|
|
|
};
|
|
|
|
|
|
|
|
#define HOSTKEY_ALGORITHMS(X) \
|
|
|
|
X(HK_ED25519, ssh_ecdsa_ed25519) \
|
|
|
|
X(HK_ECDSA, ssh_ecdsa_nistp256) \
|
|
|
|
X(HK_ECDSA, ssh_ecdsa_nistp384) \
|
|
|
|
X(HK_ECDSA, ssh_ecdsa_nistp521) \
|
|
|
|
X(HK_DSA, ssh_dss) \
|
|
|
|
X(HK_RSA, ssh_rsa) \
|
|
|
|
/* end of list */
|
|
|
|
#define COUNT_HOSTKEY_ALGORITHM(type, alg) +1
|
|
|
|
#define N_HOSTKEY_ALGORITHMS (0 HOSTKEY_ALGORITHMS(COUNT_HOSTKEY_ALGORITHM))
|
|
|
|
|
|
|
|
struct ssh_signkey_with_user_pref_id {
|
|
|
|
const ssh_keyalg *alg;
|
|
|
|
int id;
|
|
|
|
};
|
|
|
|
extern const struct ssh_signkey_with_user_pref_id
|
|
|
|
ssh2_hostkey_algs[N_HOSTKEY_ALGORITHMS];
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Enumeration of high-level classes of reason why we might need to do
|
|
|
|
* a repeat key exchange. A full detailed reason in human-readable
|
|
|
|
* string form for the Event Log is also provided, but this enum type
|
|
|
|
* is used to discriminate between classes of reason that the code
|
|
|
|
* needs to treat differently.
|
|
|
|
*
|
|
|
|
* RK_NONE == 0 is the value indicating that no rekey is currently
|
|
|
|
* needed at all. RK_INITIAL indicates that we haven't even done the
|
|
|
|
* _first_ key exchange yet. RK_SERVER indicates that we're rekeying
|
|
|
|
* because the server asked for it, not because we decided it
|
|
|
|
* ourselves. RK_NORMAL is the usual case. RK_GSS_UPDATE indicates
|
|
|
|
* that we're rekeying because we've just got new GSSAPI credentials
|
|
|
|
* (hence there's no point in doing a preliminary check for new GSS
|
|
|
|
* creds, because we already know the answer); RK_POST_USERAUTH
|
|
|
|
* indicates that _if_ we're going to need a post-userauth immediate
|
|
|
|
* rekey for any reason, this is the moment to do it.
|
|
|
|
*
|
|
|
|
* So RK_POST_USERAUTH only tells the transport layer to _consider_
|
|
|
|
* rekeying, not to definitely do it. Also, that one enum value is
|
|
|
|
* special in that the user-readable reason text is passed in to the
|
|
|
|
* transport layer as NULL, whereas fills in the reason text after it
|
|
|
|
* decides whether it needs a rekey at all. In the other cases,
|
|
|
|
* rekey_reason is passed in to the at the same time as rekey_class.
|
|
|
|
*/
|
|
|
|
typedef enum RekeyClass {
|
|
|
|
RK_NONE = 0,
|
|
|
|
RK_INITIAL,
|
|
|
|
RK_SERVER,
|
|
|
|
RK_NORMAL,
|
|
|
|
RK_POST_USERAUTH,
|
|
|
|
RK_GSS_UPDATE
|
|
|
|
} RekeyClass;
|
|
|
|
|
|
|
|
typedef struct transport_direction {
|
|
|
|
const struct ssh2_cipheralg *cipher;
|
|
|
|
const struct ssh2_macalg *mac;
|
Convert a lot of 'int' variables to 'bool'.
My normal habit these days, in new code, is to treat int and bool as
_almost_ completely separate types. I'm still willing to use C's
implicit test for zero on an integer (e.g. 'if (!blob.len)' is fine,
no need to spell it out as blob.len != 0), but generally, if a
variable is going to be conceptually a boolean, I like to declare it
bool and assign to it using 'true' or 'false' rather than 0 or 1.
PuTTY is an exception, because it predates the C99 bool, and I've
stuck to its existing coding style even when adding new code to it.
But it's been annoying me more and more, so now that I've decided C99
bool is an acceptable thing to require from our toolchain in the first
place, here's a quite thorough trawl through the source doing
'boolification'. Many variables and function parameters are now typed
as bool rather than int; many assignments of 0 or 1 to those variables
are now spelled 'true' or 'false'.
I managed this thorough conversion with the help of a custom clang
plugin that I wrote to trawl the AST and apply heuristics to point out
where things might want changing. So I've even managed to do a decent
job on parts of the code I haven't looked at in years!
To make the plugin's work easier, I pushed platform front ends
generally in the direction of using standard 'bool' in preference to
platform-specific boolean types like Windows BOOL or GTK's gboolean;
I've left the platform booleans in places they _have_ to be for the
platform APIs to work right, but variables only used by my own code
have been converted wherever I found them.
In a few places there are int values that look very like booleans in
_most_ of the places they're used, but have a rarely-used third value,
or a distinction between different nonzero values that most users
don't care about. In these cases, I've _removed_ uses of 'true' and
'false' for the return values, to emphasise that there's something
more subtle going on than a simple boolean answer:
- the 'multisel' field in dialog.h's list box structure, for which
the GTK front end in particular recognises a difference between 1
and 2 but nearly everything else treats as boolean
- the 'urgent' parameter to plug_receive, where 1 vs 2 tells you
something about the specific location of the urgent pointer, but
most clients only care about 0 vs 'something nonzero'
- the return value of wc_match, where -1 indicates a syntax error in
the wildcard.
- the return values from SSH-1 RSA-key loading functions, which use
-1 for 'wrong passphrase' and 0 for all other failures (so any
caller which already knows it's not loading an _encrypted private_
key can treat them as boolean)
- term->esc_query, and the 'query' parameter in toggle_mode in
terminal.c, which _usually_ hold 0 for ESC[123h or 1 for ESC[?123h,
but can also hold -1 for some other intervening character that we
don't support.
In a few places there's an integer that I haven't turned into a bool
even though it really _can_ only take values 0 or 1 (and, as above,
tried to make the call sites consistent in not calling those values
true and false), on the grounds that I thought it would make it more
confusing to imply that the 0 value was in some sense 'negative' or
bad and the 1 positive or good:
- the return value of plug_accepting uses the POSIXish convention of
0=success and nonzero=error; I think if I made it bool then I'd
also want to reverse its sense, and that's a job for a separate
piece of work.
- the 'screen' parameter to lineptr() in terminal.c, where 0 and 1
represent the default and alternate screens. There's no obvious
reason why one of those should be considered 'true' or 'positive'
or 'success' - they're just indices - so I've left it as int.
ssh_scp_recv had particularly confusing semantics for its previous int
return value: its call sites used '<= 0' to check for error, but it
never actually returned a negative number, just 0 or 1. Now the
function and its call sites agree that it's a bool.
In a couple of places I've renamed variables called 'ret', because I
don't like that name any more - it's unclear whether it means the
return value (in preparation) for the _containing_ function or the
return value received from a subroutine call, and occasionally I've
accidentally used the same variable for both and introduced a bug. So
where one of those got in my way, I've renamed it to 'toret' or 'retd'
(the latter short for 'returned') in line with my usual modern
practice, but I haven't done a thorough job of finding all of them.
Finally, one amusing side effect of doing this is that I've had to
separate quite a few chained assignments. It used to be perfectly fine
to write 'a = b = c = TRUE' when a,b,c were int and TRUE was just a
the 'true' defined by stdbool.h, that idiom provokes a warning from
gcc: 'suggest parentheses around assignment used as truth value'!
2018-11-02 22:23:19 +03:00
|
|
|
bool etm_mode;
|
Move client-specific SSH code into new files.
This is a major code reorganisation in preparation for making this
code base into one that can build an SSH server as well as a client.
(Mostly for purposes of using the server as a regression test suite
for the client, though I have some other possible uses in mind too.
However, it's currently no part of my plan to harden the server to the
point where it can sensibly be deployed in a hostile environment.)
In this preparatory commit, I've broken up the SSH-2 transport and
connection layers, and the SSH-1 connection layer, into multiple
source files, with each layer having its own header file containing
the shared type definitions. In each case, the new source file
contains code that's specific to the client side of the protocol, so
that a new file can be swapped in in its place when building the
server.
Mostly this is just a straightforward moving of code without changing
it very much, but there are a couple of actual changes in the process:
The parsing of SSH-2 global-request and channel open-messages is now
done by a new pair of functions in the client module. For channel
opens, I've invented a new union data type to be the return value from
that function, representing either failure (plus error message),
success (plus Channel instance to manage the new channel), or an
instruction to hand the channel over to a sharing downstream (plus a
pointer to the downstream in question).
Also, the tree234 of remote port forwardings in ssh2connection is now
initialised on first use by the client-specific code, so that's where
its compare function lives. The shared ssh2connection_free() still
takes responsibility for freeing it, but now has to check if it's
non-null first.
The outer shell of the ssh2_lportfwd_open method, for making a
local-to-remote port forwarding, is still centralised in
ssh2connection.c, but the part of it that actually constructs the
outgoing channel-open message has moved into the client code, because
that will have to change depending on whether the channel-open has to
have type direct-tcpip or forwarded-tcpip.
In the SSH-1 connection layer, half the filter_queue method has moved
out into the new client-specific code, but not all of it -
bidirectional channel maintenance messages are still handled
centrally. One exception is SSH_MSG_PORT_OPEN, which can be sent in
both directions, but with subtly different semantics - from server to
client, it's referring to a previously established remote forwarding
(and must be rejected if there isn't one that matches it), but from
client to server it's just a "direct-tcpip" request with no prior
context. So that one is in the client-specific module, and when I add
the server code it will have its own different handler.
2018-10-20 19:57:37 +03:00
|
|
|
const struct ssh_compression_alg *comp;
|
Convert a lot of 'int' variables to 'bool'.
My normal habit these days, in new code, is to treat int and bool as
_almost_ completely separate types. I'm still willing to use C's
implicit test for zero on an integer (e.g. 'if (!blob.len)' is fine,
no need to spell it out as blob.len != 0), but generally, if a
variable is going to be conceptually a boolean, I like to declare it
bool and assign to it using 'true' or 'false' rather than 0 or 1.
PuTTY is an exception, because it predates the C99 bool, and I've
stuck to its existing coding style even when adding new code to it.
But it's been annoying me more and more, so now that I've decided C99
bool is an acceptable thing to require from our toolchain in the first
place, here's a quite thorough trawl through the source doing
'boolification'. Many variables and function parameters are now typed
as bool rather than int; many assignments of 0 or 1 to those variables
are now spelled 'true' or 'false'.
I managed this thorough conversion with the help of a custom clang
plugin that I wrote to trawl the AST and apply heuristics to point out
where things might want changing. So I've even managed to do a decent
job on parts of the code I haven't looked at in years!
To make the plugin's work easier, I pushed platform front ends
generally in the direction of using standard 'bool' in preference to
platform-specific boolean types like Windows BOOL or GTK's gboolean;
I've left the platform booleans in places they _have_ to be for the
platform APIs to work right, but variables only used by my own code
have been converted wherever I found them.
In a few places there are int values that look very like booleans in
_most_ of the places they're used, but have a rarely-used third value,
or a distinction between different nonzero values that most users
don't care about. In these cases, I've _removed_ uses of 'true' and
'false' for the return values, to emphasise that there's something
more subtle going on than a simple boolean answer:
- the 'multisel' field in dialog.h's list box structure, for which
the GTK front end in particular recognises a difference between 1
and 2 but nearly everything else treats as boolean
- the 'urgent' parameter to plug_receive, where 1 vs 2 tells you
something about the specific location of the urgent pointer, but
most clients only care about 0 vs 'something nonzero'
- the return value of wc_match, where -1 indicates a syntax error in
the wildcard.
- the return values from SSH-1 RSA-key loading functions, which use
-1 for 'wrong passphrase' and 0 for all other failures (so any
caller which already knows it's not loading an _encrypted private_
key can treat them as boolean)
- term->esc_query, and the 'query' parameter in toggle_mode in
terminal.c, which _usually_ hold 0 for ESC[123h or 1 for ESC[?123h,
but can also hold -1 for some other intervening character that we
don't support.
In a few places there's an integer that I haven't turned into a bool
even though it really _can_ only take values 0 or 1 (and, as above,
tried to make the call sites consistent in not calling those values
true and false), on the grounds that I thought it would make it more
confusing to imply that the 0 value was in some sense 'negative' or
bad and the 1 positive or good:
- the return value of plug_accepting uses the POSIXish convention of
0=success and nonzero=error; I think if I made it bool then I'd
also want to reverse its sense, and that's a job for a separate
piece of work.
- the 'screen' parameter to lineptr() in terminal.c, where 0 and 1
represent the default and alternate screens. There's no obvious
reason why one of those should be considered 'true' or 'positive'
or 'success' - they're just indices - so I've left it as int.
ssh_scp_recv had particularly confusing semantics for its previous int
return value: its call sites used '<= 0' to check for error, but it
never actually returned a negative number, just 0 or 1. Now the
function and its call sites agree that it's a bool.
In a couple of places I've renamed variables called 'ret', because I
don't like that name any more - it's unclear whether it means the
return value (in preparation) for the _containing_ function or the
return value received from a subroutine call, and occasionally I've
accidentally used the same variable for both and introduced a bug. So
where one of those got in my way, I've renamed it to 'toret' or 'retd'
(the latter short for 'returned') in line with my usual modern
practice, but I haven't done a thorough job of finding all of them.
Finally, one amusing side effect of doing this is that I've had to
separate quite a few chained assignments. It used to be perfectly fine
to write 'a = b = c = TRUE' when a,b,c were int and TRUE was just a
the 'true' defined by stdbool.h, that idiom provokes a warning from
gcc: 'suggest parentheses around assignment used as truth value'!
2018-11-02 22:23:19 +03:00
|
|
|
bool comp_delayed;
|
Add an actual SSH server program.
This server is NOT SECURE! If anyone is reading this commit message,
DO NOT DEPLOY IT IN A HOSTILE-FACING ENVIRONMENT! Its purpose is to
speak the server end of everything PuTTY speaks on the client side, so
that I can test that I haven't broken PuTTY when I reorganise its
code, even things like RSA key exchange or chained auth methods which
it's hard to find a server that speaks at all.
(For this reason, it's declared with [UT] in the Recipe file, so that
it falls into the same category as programs like testbn, which won't
be installed by 'make install'.)
Working title is 'Uppity', partly for 'Universal PuTTY Protocol
Interaction Test Yoke', but mostly because it looks quite like the
word 'PuTTY' with part of it reversed. (Apparently 'test yoke' is a
very rarely used term meaning something not altogether unlike 'test
harness', which is a bit of a stretch, but it'll do.)
It doesn't actually _support_ everything I want yet. At the moment,
it's a proof of concept only. But it has most of the machinery
present, and the parts it's missing - such as chained auth methods -
should be easy enough to add because I've built in the required
flexibility, in the form of an AuthPolicy object which can request
them if it wants to. However, the current AuthPolicy object is
entirely trivial, and will let in any user with the password "weasel".
(Another way in which this is not a production-ready server is that it
also has no interaction with the OS's authentication system. In
particular, it will not only let in any user with the same password,
but it won't even change uid - it will open shells and forwardings
under whatever user id you started it up as.)
Currently, the program can only speak the SSH protocol on its standard
I/O channels (using the new FdSocket facility), so if you want it to
listen on a network port, you'll have to run it from some kind of
separate listening program similar to inetd. For my own tests, I'm not
even doing that: I'm just having PuTTY spawn it as a local proxy
process, which also conveniently eliminates the risk of anyone hostile
connecting to it.
The bulk of the actual code reorganisation is already done by previous
commits, so this change is _mostly_ just dropping in a new set of
server-specific source files alongside the client-specific ones I
created recently. The remaining changes in the shared SSH code are
numerous, but all minor:
- a few extra parameters to BPP and PPL constructors (e.g. 'are you
in server mode?'), and pass both sets of SSH-1 protocol flags from
the login to the connection layer
- in server mode, unconditionally send our version string _before_
waiting for the remote one
- a new hook in the SSH-1 BPP to handle enabling compression in
server mode, where the message exchange works the other way round
- new code in the SSH-2 BPP to do _deferred_ compression the other
way round (the non-deferred version is still nicely symmetric)
- in the SSH-2 transport layer, some adjustments to do key derivation
either way round (swapping round the identifying letters in the
various hash preimages, and making sure to list the KEXINITs in the
right order)
- also in the SSH-2 transport layer, an if statement that controls
whether we send SERVICE_REQUEST and wait for SERVICE_ACCEPT, or
vice versa
- new ConnectionLayer methods for opening outgoing channels for X and
agent forwardings
- new functions in portfwd.c to establish listening sockets suitable
for remote-to-local port forwarding (i.e. not under the direction
of a Conf the way it's done on the client side).
2018-10-21 00:09:54 +03:00
|
|
|
int mkkey_adjust;
|
Move client-specific SSH code into new files.
This is a major code reorganisation in preparation for making this
code base into one that can build an SSH server as well as a client.
(Mostly for purposes of using the server as a regression test suite
for the client, though I have some other possible uses in mind too.
However, it's currently no part of my plan to harden the server to the
point where it can sensibly be deployed in a hostile environment.)
In this preparatory commit, I've broken up the SSH-2 transport and
connection layers, and the SSH-1 connection layer, into multiple
source files, with each layer having its own header file containing
the shared type definitions. In each case, the new source file
contains code that's specific to the client side of the protocol, so
that a new file can be swapped in in its place when building the
server.
Mostly this is just a straightforward moving of code without changing
it very much, but there are a couple of actual changes in the process:
The parsing of SSH-2 global-request and channel open-messages is now
done by a new pair of functions in the client module. For channel
opens, I've invented a new union data type to be the return value from
that function, representing either failure (plus error message),
success (plus Channel instance to manage the new channel), or an
instruction to hand the channel over to a sharing downstream (plus a
pointer to the downstream in question).
Also, the tree234 of remote port forwardings in ssh2connection is now
initialised on first use by the client-specific code, so that's where
its compare function lives. The shared ssh2connection_free() still
takes responsibility for freeing it, but now has to check if it's
non-null first.
The outer shell of the ssh2_lportfwd_open method, for making a
local-to-remote port forwarding, is still centralised in
ssh2connection.c, but the part of it that actually constructs the
outgoing channel-open message has moved into the client code, because
that will have to change depending on whether the channel-open has to
have type direct-tcpip or forwarded-tcpip.
In the SSH-1 connection layer, half the filter_queue method has moved
out into the new client-specific code, but not all of it -
bidirectional channel maintenance messages are still handled
centrally. One exception is SSH_MSG_PORT_OPEN, which can be sent in
both directions, but with subtly different semantics - from server to
client, it's referring to a previously established remote forwarding
(and must be rejected if there isn't one that matches it), but from
client to server it's just a "direct-tcpip" request with no prior
context. So that one is in the client-specific module, and when I add
the server code it will have its own different handler.
2018-10-20 19:57:37 +03:00
|
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|
} transport_direction;
|
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struct ssh2_transport_state {
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|
int crState, crStateKex;
|
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|
PacketProtocolLayer *higher_layer;
|
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|
PktInQueue pq_in_higher;
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|
PktOutQueue pq_out_higher;
|
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|
IdempotentCallback ic_pq_out_higher;
|
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|
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|
|
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|
Conf *conf;
|
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char *savedhost;
|
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int savedport;
|
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const char *rekey_reason;
|
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enum RekeyClass rekey_class;
|
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|
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unsigned long max_data_size;
|
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const struct ssh_kex *kex_alg;
|
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const ssh_keyalg *hostkey_alg;
|
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char *hostkey_str; /* string representation, for easy checking in rekeys */
|
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unsigned char session_id[SSH2_KEX_MAX_HASH_LEN];
|
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int session_id_len;
|
Convert a lot of 'int' variables to 'bool'.
My normal habit these days, in new code, is to treat int and bool as
_almost_ completely separate types. I'm still willing to use C's
implicit test for zero on an integer (e.g. 'if (!blob.len)' is fine,
no need to spell it out as blob.len != 0), but generally, if a
variable is going to be conceptually a boolean, I like to declare it
bool and assign to it using 'true' or 'false' rather than 0 or 1.
PuTTY is an exception, because it predates the C99 bool, and I've
stuck to its existing coding style even when adding new code to it.
But it's been annoying me more and more, so now that I've decided C99
bool is an acceptable thing to require from our toolchain in the first
place, here's a quite thorough trawl through the source doing
'boolification'. Many variables and function parameters are now typed
as bool rather than int; many assignments of 0 or 1 to those variables
are now spelled 'true' or 'false'.
I managed this thorough conversion with the help of a custom clang
plugin that I wrote to trawl the AST and apply heuristics to point out
where things might want changing. So I've even managed to do a decent
job on parts of the code I haven't looked at in years!
To make the plugin's work easier, I pushed platform front ends
generally in the direction of using standard 'bool' in preference to
platform-specific boolean types like Windows BOOL or GTK's gboolean;
I've left the platform booleans in places they _have_ to be for the
platform APIs to work right, but variables only used by my own code
have been converted wherever I found them.
In a few places there are int values that look very like booleans in
_most_ of the places they're used, but have a rarely-used third value,
or a distinction between different nonzero values that most users
don't care about. In these cases, I've _removed_ uses of 'true' and
'false' for the return values, to emphasise that there's something
more subtle going on than a simple boolean answer:
- the 'multisel' field in dialog.h's list box structure, for which
the GTK front end in particular recognises a difference between 1
and 2 but nearly everything else treats as boolean
- the 'urgent' parameter to plug_receive, where 1 vs 2 tells you
something about the specific location of the urgent pointer, but
most clients only care about 0 vs 'something nonzero'
- the return value of wc_match, where -1 indicates a syntax error in
the wildcard.
- the return values from SSH-1 RSA-key loading functions, which use
-1 for 'wrong passphrase' and 0 for all other failures (so any
caller which already knows it's not loading an _encrypted private_
key can treat them as boolean)
- term->esc_query, and the 'query' parameter in toggle_mode in
terminal.c, which _usually_ hold 0 for ESC[123h or 1 for ESC[?123h,
but can also hold -1 for some other intervening character that we
don't support.
In a few places there's an integer that I haven't turned into a bool
even though it really _can_ only take values 0 or 1 (and, as above,
tried to make the call sites consistent in not calling those values
true and false), on the grounds that I thought it would make it more
confusing to imply that the 0 value was in some sense 'negative' or
bad and the 1 positive or good:
- the return value of plug_accepting uses the POSIXish convention of
0=success and nonzero=error; I think if I made it bool then I'd
also want to reverse its sense, and that's a job for a separate
piece of work.
- the 'screen' parameter to lineptr() in terminal.c, where 0 and 1
represent the default and alternate screens. There's no obvious
reason why one of those should be considered 'true' or 'positive'
or 'success' - they're just indices - so I've left it as int.
ssh_scp_recv had particularly confusing semantics for its previous int
return value: its call sites used '<= 0' to check for error, but it
never actually returned a negative number, just 0 or 1. Now the
function and its call sites agree that it's a bool.
In a couple of places I've renamed variables called 'ret', because I
don't like that name any more - it's unclear whether it means the
return value (in preparation) for the _containing_ function or the
return value received from a subroutine call, and occasionally I've
accidentally used the same variable for both and introduced a bug. So
where one of those got in my way, I've renamed it to 'toret' or 'retd'
(the latter short for 'returned') in line with my usual modern
practice, but I haven't done a thorough job of finding all of them.
Finally, one amusing side effect of doing this is that I've had to
separate quite a few chained assignments. It used to be perfectly fine
to write 'a = b = c = TRUE' when a,b,c were int and TRUE was just a
the 'true' defined by stdbool.h, that idiom provokes a warning from
gcc: 'suggest parentheses around assignment used as truth value'!
2018-11-02 22:23:19 +03:00
|
|
|
int dh_min_size, dh_max_size;
|
|
|
|
bool dh_got_size_bounds;
|
Move client-specific SSH code into new files.
This is a major code reorganisation in preparation for making this
code base into one that can build an SSH server as well as a client.
(Mostly for purposes of using the server as a regression test suite
for the client, though I have some other possible uses in mind too.
However, it's currently no part of my plan to harden the server to the
point where it can sensibly be deployed in a hostile environment.)
In this preparatory commit, I've broken up the SSH-2 transport and
connection layers, and the SSH-1 connection layer, into multiple
source files, with each layer having its own header file containing
the shared type definitions. In each case, the new source file
contains code that's specific to the client side of the protocol, so
that a new file can be swapped in in its place when building the
server.
Mostly this is just a straightforward moving of code without changing
it very much, but there are a couple of actual changes in the process:
The parsing of SSH-2 global-request and channel open-messages is now
done by a new pair of functions in the client module. For channel
opens, I've invented a new union data type to be the return value from
that function, representing either failure (plus error message),
success (plus Channel instance to manage the new channel), or an
instruction to hand the channel over to a sharing downstream (plus a
pointer to the downstream in question).
Also, the tree234 of remote port forwardings in ssh2connection is now
initialised on first use by the client-specific code, so that's where
its compare function lives. The shared ssh2connection_free() still
takes responsibility for freeing it, but now has to check if it's
non-null first.
The outer shell of the ssh2_lportfwd_open method, for making a
local-to-remote port forwarding, is still centralised in
ssh2connection.c, but the part of it that actually constructs the
outgoing channel-open message has moved into the client code, because
that will have to change depending on whether the channel-open has to
have type direct-tcpip or forwarded-tcpip.
In the SSH-1 connection layer, half the filter_queue method has moved
out into the new client-specific code, but not all of it -
bidirectional channel maintenance messages are still handled
centrally. One exception is SSH_MSG_PORT_OPEN, which can be sent in
both directions, but with subtly different semantics - from server to
client, it's referring to a previously established remote forwarding
(and must be rejected if there isn't one that matches it), but from
client to server it's just a "direct-tcpip" request with no prior
context. So that one is in the client-specific module, and when I add
the server code it will have its own different handler.
2018-10-20 19:57:37 +03:00
|
|
|
struct dh_ctx *dh_ctx;
|
|
|
|
ssh_hash *exhash;
|
|
|
|
|
|
|
|
struct DataTransferStats *stats;
|
|
|
|
|
|
|
|
char *client_greeting, *server_greeting;
|
|
|
|
|
Convert a lot of 'int' variables to 'bool'.
My normal habit these days, in new code, is to treat int and bool as
_almost_ completely separate types. I'm still willing to use C's
implicit test for zero on an integer (e.g. 'if (!blob.len)' is fine,
no need to spell it out as blob.len != 0), but generally, if a
variable is going to be conceptually a boolean, I like to declare it
bool and assign to it using 'true' or 'false' rather than 0 or 1.
PuTTY is an exception, because it predates the C99 bool, and I've
stuck to its existing coding style even when adding new code to it.
But it's been annoying me more and more, so now that I've decided C99
bool is an acceptable thing to require from our toolchain in the first
place, here's a quite thorough trawl through the source doing
'boolification'. Many variables and function parameters are now typed
as bool rather than int; many assignments of 0 or 1 to those variables
are now spelled 'true' or 'false'.
I managed this thorough conversion with the help of a custom clang
plugin that I wrote to trawl the AST and apply heuristics to point out
where things might want changing. So I've even managed to do a decent
job on parts of the code I haven't looked at in years!
To make the plugin's work easier, I pushed platform front ends
generally in the direction of using standard 'bool' in preference to
platform-specific boolean types like Windows BOOL or GTK's gboolean;
I've left the platform booleans in places they _have_ to be for the
platform APIs to work right, but variables only used by my own code
have been converted wherever I found them.
In a few places there are int values that look very like booleans in
_most_ of the places they're used, but have a rarely-used third value,
or a distinction between different nonzero values that most users
don't care about. In these cases, I've _removed_ uses of 'true' and
'false' for the return values, to emphasise that there's something
more subtle going on than a simple boolean answer:
- the 'multisel' field in dialog.h's list box structure, for which
the GTK front end in particular recognises a difference between 1
and 2 but nearly everything else treats as boolean
- the 'urgent' parameter to plug_receive, where 1 vs 2 tells you
something about the specific location of the urgent pointer, but
most clients only care about 0 vs 'something nonzero'
- the return value of wc_match, where -1 indicates a syntax error in
the wildcard.
- the return values from SSH-1 RSA-key loading functions, which use
-1 for 'wrong passphrase' and 0 for all other failures (so any
caller which already knows it's not loading an _encrypted private_
key can treat them as boolean)
- term->esc_query, and the 'query' parameter in toggle_mode in
terminal.c, which _usually_ hold 0 for ESC[123h or 1 for ESC[?123h,
but can also hold -1 for some other intervening character that we
don't support.
In a few places there's an integer that I haven't turned into a bool
even though it really _can_ only take values 0 or 1 (and, as above,
tried to make the call sites consistent in not calling those values
true and false), on the grounds that I thought it would make it more
confusing to imply that the 0 value was in some sense 'negative' or
bad and the 1 positive or good:
- the return value of plug_accepting uses the POSIXish convention of
0=success and nonzero=error; I think if I made it bool then I'd
also want to reverse its sense, and that's a job for a separate
piece of work.
- the 'screen' parameter to lineptr() in terminal.c, where 0 and 1
represent the default and alternate screens. There's no obvious
reason why one of those should be considered 'true' or 'positive'
or 'success' - they're just indices - so I've left it as int.
ssh_scp_recv had particularly confusing semantics for its previous int
return value: its call sites used '<= 0' to check for error, but it
never actually returned a negative number, just 0 or 1. Now the
function and its call sites agree that it's a bool.
In a couple of places I've renamed variables called 'ret', because I
don't like that name any more - it's unclear whether it means the
return value (in preparation) for the _containing_ function or the
return value received from a subroutine call, and occasionally I've
accidentally used the same variable for both and introduced a bug. So
where one of those got in my way, I've renamed it to 'toret' or 'retd'
(the latter short for 'returned') in line with my usual modern
practice, but I haven't done a thorough job of finding all of them.
Finally, one amusing side effect of doing this is that I've had to
separate quite a few chained assignments. It used to be perfectly fine
to write 'a = b = c = TRUE' when a,b,c were int and TRUE was just a
the 'true' defined by stdbool.h, that idiom provokes a warning from
gcc: 'suggest parentheses around assignment used as truth value'!
2018-11-02 22:23:19 +03:00
|
|
|
bool kex_in_progress;
|
Move client-specific SSH code into new files.
This is a major code reorganisation in preparation for making this
code base into one that can build an SSH server as well as a client.
(Mostly for purposes of using the server as a regression test suite
for the client, though I have some other possible uses in mind too.
However, it's currently no part of my plan to harden the server to the
point where it can sensibly be deployed in a hostile environment.)
In this preparatory commit, I've broken up the SSH-2 transport and
connection layers, and the SSH-1 connection layer, into multiple
source files, with each layer having its own header file containing
the shared type definitions. In each case, the new source file
contains code that's specific to the client side of the protocol, so
that a new file can be swapped in in its place when building the
server.
Mostly this is just a straightforward moving of code without changing
it very much, but there are a couple of actual changes in the process:
The parsing of SSH-2 global-request and channel open-messages is now
done by a new pair of functions in the client module. For channel
opens, I've invented a new union data type to be the return value from
that function, representing either failure (plus error message),
success (plus Channel instance to manage the new channel), or an
instruction to hand the channel over to a sharing downstream (plus a
pointer to the downstream in question).
Also, the tree234 of remote port forwardings in ssh2connection is now
initialised on first use by the client-specific code, so that's where
its compare function lives. The shared ssh2connection_free() still
takes responsibility for freeing it, but now has to check if it's
non-null first.
The outer shell of the ssh2_lportfwd_open method, for making a
local-to-remote port forwarding, is still centralised in
ssh2connection.c, but the part of it that actually constructs the
outgoing channel-open message has moved into the client code, because
that will have to change depending on whether the channel-open has to
have type direct-tcpip or forwarded-tcpip.
In the SSH-1 connection layer, half the filter_queue method has moved
out into the new client-specific code, but not all of it -
bidirectional channel maintenance messages are still handled
centrally. One exception is SSH_MSG_PORT_OPEN, which can be sent in
both directions, but with subtly different semantics - from server to
client, it's referring to a previously established remote forwarding
(and must be rejected if there isn't one that matches it), but from
client to server it's just a "direct-tcpip" request with no prior
context. So that one is in the client-specific module, and when I add
the server code it will have its own different handler.
2018-10-20 19:57:37 +03:00
|
|
|
unsigned long next_rekey, last_rekey;
|
|
|
|
const char *deferred_rekey_reason;
|
Convert a lot of 'int' variables to 'bool'.
My normal habit these days, in new code, is to treat int and bool as
_almost_ completely separate types. I'm still willing to use C's
implicit test for zero on an integer (e.g. 'if (!blob.len)' is fine,
no need to spell it out as blob.len != 0), but generally, if a
variable is going to be conceptually a boolean, I like to declare it
bool and assign to it using 'true' or 'false' rather than 0 or 1.
PuTTY is an exception, because it predates the C99 bool, and I've
stuck to its existing coding style even when adding new code to it.
But it's been annoying me more and more, so now that I've decided C99
bool is an acceptable thing to require from our toolchain in the first
place, here's a quite thorough trawl through the source doing
'boolification'. Many variables and function parameters are now typed
as bool rather than int; many assignments of 0 or 1 to those variables
are now spelled 'true' or 'false'.
I managed this thorough conversion with the help of a custom clang
plugin that I wrote to trawl the AST and apply heuristics to point out
where things might want changing. So I've even managed to do a decent
job on parts of the code I haven't looked at in years!
To make the plugin's work easier, I pushed platform front ends
generally in the direction of using standard 'bool' in preference to
platform-specific boolean types like Windows BOOL or GTK's gboolean;
I've left the platform booleans in places they _have_ to be for the
platform APIs to work right, but variables only used by my own code
have been converted wherever I found them.
In a few places there are int values that look very like booleans in
_most_ of the places they're used, but have a rarely-used third value,
or a distinction between different nonzero values that most users
don't care about. In these cases, I've _removed_ uses of 'true' and
'false' for the return values, to emphasise that there's something
more subtle going on than a simple boolean answer:
- the 'multisel' field in dialog.h's list box structure, for which
the GTK front end in particular recognises a difference between 1
and 2 but nearly everything else treats as boolean
- the 'urgent' parameter to plug_receive, where 1 vs 2 tells you
something about the specific location of the urgent pointer, but
most clients only care about 0 vs 'something nonzero'
- the return value of wc_match, where -1 indicates a syntax error in
the wildcard.
- the return values from SSH-1 RSA-key loading functions, which use
-1 for 'wrong passphrase' and 0 for all other failures (so any
caller which already knows it's not loading an _encrypted private_
key can treat them as boolean)
- term->esc_query, and the 'query' parameter in toggle_mode in
terminal.c, which _usually_ hold 0 for ESC[123h or 1 for ESC[?123h,
but can also hold -1 for some other intervening character that we
don't support.
In a few places there's an integer that I haven't turned into a bool
even though it really _can_ only take values 0 or 1 (and, as above,
tried to make the call sites consistent in not calling those values
true and false), on the grounds that I thought it would make it more
confusing to imply that the 0 value was in some sense 'negative' or
bad and the 1 positive or good:
- the return value of plug_accepting uses the POSIXish convention of
0=success and nonzero=error; I think if I made it bool then I'd
also want to reverse its sense, and that's a job for a separate
piece of work.
- the 'screen' parameter to lineptr() in terminal.c, where 0 and 1
represent the default and alternate screens. There's no obvious
reason why one of those should be considered 'true' or 'positive'
or 'success' - they're just indices - so I've left it as int.
ssh_scp_recv had particularly confusing semantics for its previous int
return value: its call sites used '<= 0' to check for error, but it
never actually returned a negative number, just 0 or 1. Now the
function and its call sites agree that it's a bool.
In a couple of places I've renamed variables called 'ret', because I
don't like that name any more - it's unclear whether it means the
return value (in preparation) for the _containing_ function or the
return value received from a subroutine call, and occasionally I've
accidentally used the same variable for both and introduced a bug. So
where one of those got in my way, I've renamed it to 'toret' or 'retd'
(the latter short for 'returned') in line with my usual modern
practice, but I haven't done a thorough job of finding all of them.
Finally, one amusing side effect of doing this is that I've had to
separate quite a few chained assignments. It used to be perfectly fine
to write 'a = b = c = TRUE' when a,b,c were int and TRUE was just a
the 'true' defined by stdbool.h, that idiom provokes a warning from
gcc: 'suggest parentheses around assignment used as truth value'!
2018-11-02 22:23:19 +03:00
|
|
|
bool higher_layer_ok;
|
Move client-specific SSH code into new files.
This is a major code reorganisation in preparation for making this
code base into one that can build an SSH server as well as a client.
(Mostly for purposes of using the server as a regression test suite
for the client, though I have some other possible uses in mind too.
However, it's currently no part of my plan to harden the server to the
point where it can sensibly be deployed in a hostile environment.)
In this preparatory commit, I've broken up the SSH-2 transport and
connection layers, and the SSH-1 connection layer, into multiple
source files, with each layer having its own header file containing
the shared type definitions. In each case, the new source file
contains code that's specific to the client side of the protocol, so
that a new file can be swapped in in its place when building the
server.
Mostly this is just a straightforward moving of code without changing
it very much, but there are a couple of actual changes in the process:
The parsing of SSH-2 global-request and channel open-messages is now
done by a new pair of functions in the client module. For channel
opens, I've invented a new union data type to be the return value from
that function, representing either failure (plus error message),
success (plus Channel instance to manage the new channel), or an
instruction to hand the channel over to a sharing downstream (plus a
pointer to the downstream in question).
Also, the tree234 of remote port forwardings in ssh2connection is now
initialised on first use by the client-specific code, so that's where
its compare function lives. The shared ssh2connection_free() still
takes responsibility for freeing it, but now has to check if it's
non-null first.
The outer shell of the ssh2_lportfwd_open method, for making a
local-to-remote port forwarding, is still centralised in
ssh2connection.c, but the part of it that actually constructs the
outgoing channel-open message has moved into the client code, because
that will have to change depending on whether the channel-open has to
have type direct-tcpip or forwarded-tcpip.
In the SSH-1 connection layer, half the filter_queue method has moved
out into the new client-specific code, but not all of it -
bidirectional channel maintenance messages are still handled
centrally. One exception is SSH_MSG_PORT_OPEN, which can be sent in
both directions, but with subtly different semantics - from server to
client, it's referring to a previously established remote forwarding
(and must be rejected if there isn't one that matches it), but from
client to server it's just a "direct-tcpip" request with no prior
context. So that one is in the client-specific module, and when I add
the server code it will have its own different handler.
2018-10-20 19:57:37 +03:00
|
|
|
|
|
|
|
/*
|
|
|
|
* Fully qualified host name, which we need if doing GSSAPI.
|
|
|
|
*/
|
|
|
|
char *fullhostname;
|
|
|
|
|
|
|
|
/* shgss is outside the ifdef on purpose to keep APIs simple. If
|
|
|
|
* NO_GSSAPI is not defined, then it's just an opaque structure
|
|
|
|
* tag and the pointer will be NULL. */
|
|
|
|
struct ssh_connection_shared_gss_state *shgss;
|
|
|
|
#ifndef NO_GSSAPI
|
|
|
|
int gss_status;
|
|
|
|
time_t gss_cred_expiry; /* Re-delegate if newer */
|
|
|
|
unsigned long gss_ctxt_lifetime; /* Re-delegate when short */
|
|
|
|
#endif
|
|
|
|
ssh_transient_hostkey_cache *thc;
|
|
|
|
|
Convert a lot of 'int' variables to 'bool'.
My normal habit these days, in new code, is to treat int and bool as
_almost_ completely separate types. I'm still willing to use C's
implicit test for zero on an integer (e.g. 'if (!blob.len)' is fine,
no need to spell it out as blob.len != 0), but generally, if a
variable is going to be conceptually a boolean, I like to declare it
bool and assign to it using 'true' or 'false' rather than 0 or 1.
PuTTY is an exception, because it predates the C99 bool, and I've
stuck to its existing coding style even when adding new code to it.
But it's been annoying me more and more, so now that I've decided C99
bool is an acceptable thing to require from our toolchain in the first
place, here's a quite thorough trawl through the source doing
'boolification'. Many variables and function parameters are now typed
as bool rather than int; many assignments of 0 or 1 to those variables
are now spelled 'true' or 'false'.
I managed this thorough conversion with the help of a custom clang
plugin that I wrote to trawl the AST and apply heuristics to point out
where things might want changing. So I've even managed to do a decent
job on parts of the code I haven't looked at in years!
To make the plugin's work easier, I pushed platform front ends
generally in the direction of using standard 'bool' in preference to
platform-specific boolean types like Windows BOOL or GTK's gboolean;
I've left the platform booleans in places they _have_ to be for the
platform APIs to work right, but variables only used by my own code
have been converted wherever I found them.
In a few places there are int values that look very like booleans in
_most_ of the places they're used, but have a rarely-used third value,
or a distinction between different nonzero values that most users
don't care about. In these cases, I've _removed_ uses of 'true' and
'false' for the return values, to emphasise that there's something
more subtle going on than a simple boolean answer:
- the 'multisel' field in dialog.h's list box structure, for which
the GTK front end in particular recognises a difference between 1
and 2 but nearly everything else treats as boolean
- the 'urgent' parameter to plug_receive, where 1 vs 2 tells you
something about the specific location of the urgent pointer, but
most clients only care about 0 vs 'something nonzero'
- the return value of wc_match, where -1 indicates a syntax error in
the wildcard.
- the return values from SSH-1 RSA-key loading functions, which use
-1 for 'wrong passphrase' and 0 for all other failures (so any
caller which already knows it's not loading an _encrypted private_
key can treat them as boolean)
- term->esc_query, and the 'query' parameter in toggle_mode in
terminal.c, which _usually_ hold 0 for ESC[123h or 1 for ESC[?123h,
but can also hold -1 for some other intervening character that we
don't support.
In a few places there's an integer that I haven't turned into a bool
even though it really _can_ only take values 0 or 1 (and, as above,
tried to make the call sites consistent in not calling those values
true and false), on the grounds that I thought it would make it more
confusing to imply that the 0 value was in some sense 'negative' or
bad and the 1 positive or good:
- the return value of plug_accepting uses the POSIXish convention of
0=success and nonzero=error; I think if I made it bool then I'd
also want to reverse its sense, and that's a job for a separate
piece of work.
- the 'screen' parameter to lineptr() in terminal.c, where 0 and 1
represent the default and alternate screens. There's no obvious
reason why one of those should be considered 'true' or 'positive'
or 'success' - they're just indices - so I've left it as int.
ssh_scp_recv had particularly confusing semantics for its previous int
return value: its call sites used '<= 0' to check for error, but it
never actually returned a negative number, just 0 or 1. Now the
function and its call sites agree that it's a bool.
In a couple of places I've renamed variables called 'ret', because I
don't like that name any more - it's unclear whether it means the
return value (in preparation) for the _containing_ function or the
return value received from a subroutine call, and occasionally I've
accidentally used the same variable for both and introduced a bug. So
where one of those got in my way, I've renamed it to 'toret' or 'retd'
(the latter short for 'returned') in line with my usual modern
practice, but I haven't done a thorough job of finding all of them.
Finally, one amusing side effect of doing this is that I've had to
separate quite a few chained assignments. It used to be perfectly fine
to write 'a = b = c = TRUE' when a,b,c were int and TRUE was just a
the 'true' defined by stdbool.h, that idiom provokes a warning from
gcc: 'suggest parentheses around assignment used as truth value'!
2018-11-02 22:23:19 +03:00
|
|
|
bool gss_kex_used;
|
Move client-specific SSH code into new files.
This is a major code reorganisation in preparation for making this
code base into one that can build an SSH server as well as a client.
(Mostly for purposes of using the server as a regression test suite
for the client, though I have some other possible uses in mind too.
However, it's currently no part of my plan to harden the server to the
point where it can sensibly be deployed in a hostile environment.)
In this preparatory commit, I've broken up the SSH-2 transport and
connection layers, and the SSH-1 connection layer, into multiple
source files, with each layer having its own header file containing
the shared type definitions. In each case, the new source file
contains code that's specific to the client side of the protocol, so
that a new file can be swapped in in its place when building the
server.
Mostly this is just a straightforward moving of code without changing
it very much, but there are a couple of actual changes in the process:
The parsing of SSH-2 global-request and channel open-messages is now
done by a new pair of functions in the client module. For channel
opens, I've invented a new union data type to be the return value from
that function, representing either failure (plus error message),
success (plus Channel instance to manage the new channel), or an
instruction to hand the channel over to a sharing downstream (plus a
pointer to the downstream in question).
Also, the tree234 of remote port forwardings in ssh2connection is now
initialised on first use by the client-specific code, so that's where
its compare function lives. The shared ssh2connection_free() still
takes responsibility for freeing it, but now has to check if it's
non-null first.
The outer shell of the ssh2_lportfwd_open method, for making a
local-to-remote port forwarding, is still centralised in
ssh2connection.c, but the part of it that actually constructs the
outgoing channel-open message has moved into the client code, because
that will have to change depending on whether the channel-open has to
have type direct-tcpip or forwarded-tcpip.
In the SSH-1 connection layer, half the filter_queue method has moved
out into the new client-specific code, but not all of it -
bidirectional channel maintenance messages are still handled
centrally. One exception is SSH_MSG_PORT_OPEN, which can be sent in
both directions, but with subtly different semantics - from server to
client, it's referring to a previously established remote forwarding
(and must be rejected if there isn't one that matches it), but from
client to server it's just a "direct-tcpip" request with no prior
context. So that one is in the client-specific module, and when I add
the server code it will have its own different handler.
2018-10-20 19:57:37 +03:00
|
|
|
|
Convert a lot of 'int' variables to 'bool'.
My normal habit these days, in new code, is to treat int and bool as
_almost_ completely separate types. I'm still willing to use C's
implicit test for zero on an integer (e.g. 'if (!blob.len)' is fine,
no need to spell it out as blob.len != 0), but generally, if a
variable is going to be conceptually a boolean, I like to declare it
bool and assign to it using 'true' or 'false' rather than 0 or 1.
PuTTY is an exception, because it predates the C99 bool, and I've
stuck to its existing coding style even when adding new code to it.
But it's been annoying me more and more, so now that I've decided C99
bool is an acceptable thing to require from our toolchain in the first
place, here's a quite thorough trawl through the source doing
'boolification'. Many variables and function parameters are now typed
as bool rather than int; many assignments of 0 or 1 to those variables
are now spelled 'true' or 'false'.
I managed this thorough conversion with the help of a custom clang
plugin that I wrote to trawl the AST and apply heuristics to point out
where things might want changing. So I've even managed to do a decent
job on parts of the code I haven't looked at in years!
To make the plugin's work easier, I pushed platform front ends
generally in the direction of using standard 'bool' in preference to
platform-specific boolean types like Windows BOOL or GTK's gboolean;
I've left the platform booleans in places they _have_ to be for the
platform APIs to work right, but variables only used by my own code
have been converted wherever I found them.
In a few places there are int values that look very like booleans in
_most_ of the places they're used, but have a rarely-used third value,
or a distinction between different nonzero values that most users
don't care about. In these cases, I've _removed_ uses of 'true' and
'false' for the return values, to emphasise that there's something
more subtle going on than a simple boolean answer:
- the 'multisel' field in dialog.h's list box structure, for which
the GTK front end in particular recognises a difference between 1
and 2 but nearly everything else treats as boolean
- the 'urgent' parameter to plug_receive, where 1 vs 2 tells you
something about the specific location of the urgent pointer, but
most clients only care about 0 vs 'something nonzero'
- the return value of wc_match, where -1 indicates a syntax error in
the wildcard.
- the return values from SSH-1 RSA-key loading functions, which use
-1 for 'wrong passphrase' and 0 for all other failures (so any
caller which already knows it's not loading an _encrypted private_
key can treat them as boolean)
- term->esc_query, and the 'query' parameter in toggle_mode in
terminal.c, which _usually_ hold 0 for ESC[123h or 1 for ESC[?123h,
but can also hold -1 for some other intervening character that we
don't support.
In a few places there's an integer that I haven't turned into a bool
even though it really _can_ only take values 0 or 1 (and, as above,
tried to make the call sites consistent in not calling those values
true and false), on the grounds that I thought it would make it more
confusing to imply that the 0 value was in some sense 'negative' or
bad and the 1 positive or good:
- the return value of plug_accepting uses the POSIXish convention of
0=success and nonzero=error; I think if I made it bool then I'd
also want to reverse its sense, and that's a job for a separate
piece of work.
- the 'screen' parameter to lineptr() in terminal.c, where 0 and 1
represent the default and alternate screens. There's no obvious
reason why one of those should be considered 'true' or 'positive'
or 'success' - they're just indices - so I've left it as int.
ssh_scp_recv had particularly confusing semantics for its previous int
return value: its call sites used '<= 0' to check for error, but it
never actually returned a negative number, just 0 or 1. Now the
function and its call sites agree that it's a bool.
In a couple of places I've renamed variables called 'ret', because I
don't like that name any more - it's unclear whether it means the
return value (in preparation) for the _containing_ function or the
return value received from a subroutine call, and occasionally I've
accidentally used the same variable for both and introduced a bug. So
where one of those got in my way, I've renamed it to 'toret' or 'retd'
(the latter short for 'returned') in line with my usual modern
practice, but I haven't done a thorough job of finding all of them.
Finally, one amusing side effect of doing this is that I've had to
separate quite a few chained assignments. It used to be perfectly fine
to write 'a = b = c = TRUE' when a,b,c were int and TRUE was just a
the 'true' defined by stdbool.h, that idiom provokes a warning from
gcc: 'suggest parentheses around assignment used as truth value'!
2018-11-02 22:23:19 +03:00
|
|
|
int nbits, pbits;
|
|
|
|
bool warn_kex, warn_hk, warn_cscipher, warn_sccipher;
|
Move client-specific SSH code into new files.
This is a major code reorganisation in preparation for making this
code base into one that can build an SSH server as well as a client.
(Mostly for purposes of using the server as a regression test suite
for the client, though I have some other possible uses in mind too.
However, it's currently no part of my plan to harden the server to the
point where it can sensibly be deployed in a hostile environment.)
In this preparatory commit, I've broken up the SSH-2 transport and
connection layers, and the SSH-1 connection layer, into multiple
source files, with each layer having its own header file containing
the shared type definitions. In each case, the new source file
contains code that's specific to the client side of the protocol, so
that a new file can be swapped in in its place when building the
server.
Mostly this is just a straightforward moving of code without changing
it very much, but there are a couple of actual changes in the process:
The parsing of SSH-2 global-request and channel open-messages is now
done by a new pair of functions in the client module. For channel
opens, I've invented a new union data type to be the return value from
that function, representing either failure (plus error message),
success (plus Channel instance to manage the new channel), or an
instruction to hand the channel over to a sharing downstream (plus a
pointer to the downstream in question).
Also, the tree234 of remote port forwardings in ssh2connection is now
initialised on first use by the client-specific code, so that's where
its compare function lives. The shared ssh2connection_free() still
takes responsibility for freeing it, but now has to check if it's
non-null first.
The outer shell of the ssh2_lportfwd_open method, for making a
local-to-remote port forwarding, is still centralised in
ssh2connection.c, but the part of it that actually constructs the
outgoing channel-open message has moved into the client code, because
that will have to change depending on whether the channel-open has to
have type direct-tcpip or forwarded-tcpip.
In the SSH-1 connection layer, half the filter_queue method has moved
out into the new client-specific code, but not all of it -
bidirectional channel maintenance messages are still handled
centrally. One exception is SSH_MSG_PORT_OPEN, which can be sent in
both directions, but with subtly different semantics - from server to
client, it's referring to a previously established remote forwarding
(and must be rejected if there isn't one that matches it), but from
client to server it's just a "direct-tcpip" request with no prior
context. So that one is in the client-specific module, and when I add
the server code it will have its own different handler.
2018-10-20 19:57:37 +03:00
|
|
|
Bignum p, g, e, f, K;
|
Add an actual SSH server program.
This server is NOT SECURE! If anyone is reading this commit message,
DO NOT DEPLOY IT IN A HOSTILE-FACING ENVIRONMENT! Its purpose is to
speak the server end of everything PuTTY speaks on the client side, so
that I can test that I haven't broken PuTTY when I reorganise its
code, even things like RSA key exchange or chained auth methods which
it's hard to find a server that speaks at all.
(For this reason, it's declared with [UT] in the Recipe file, so that
it falls into the same category as programs like testbn, which won't
be installed by 'make install'.)
Working title is 'Uppity', partly for 'Universal PuTTY Protocol
Interaction Test Yoke', but mostly because it looks quite like the
word 'PuTTY' with part of it reversed. (Apparently 'test yoke' is a
very rarely used term meaning something not altogether unlike 'test
harness', which is a bit of a stretch, but it'll do.)
It doesn't actually _support_ everything I want yet. At the moment,
it's a proof of concept only. But it has most of the machinery
present, and the parts it's missing - such as chained auth methods -
should be easy enough to add because I've built in the required
flexibility, in the form of an AuthPolicy object which can request
them if it wants to. However, the current AuthPolicy object is
entirely trivial, and will let in any user with the password "weasel".
(Another way in which this is not a production-ready server is that it
also has no interaction with the OS's authentication system. In
particular, it will not only let in any user with the same password,
but it won't even change uid - it will open shells and forwardings
under whatever user id you started it up as.)
Currently, the program can only speak the SSH protocol on its standard
I/O channels (using the new FdSocket facility), so if you want it to
listen on a network port, you'll have to run it from some kind of
separate listening program similar to inetd. For my own tests, I'm not
even doing that: I'm just having PuTTY spawn it as a local proxy
process, which also conveniently eliminates the risk of anyone hostile
connecting to it.
The bulk of the actual code reorganisation is already done by previous
commits, so this change is _mostly_ just dropping in a new set of
server-specific source files alongside the client-specific ones I
created recently. The remaining changes in the shared SSH code are
numerous, but all minor:
- a few extra parameters to BPP and PPL constructors (e.g. 'are you
in server mode?'), and pass both sets of SSH-1 protocol flags from
the login to the connection layer
- in server mode, unconditionally send our version string _before_
waiting for the remote one
- a new hook in the SSH-1 BPP to handle enabling compression in
server mode, where the message exchange works the other way round
- new code in the SSH-2 BPP to do _deferred_ compression the other
way round (the non-deferred version is still nicely symmetric)
- in the SSH-2 transport layer, some adjustments to do key derivation
either way round (swapping round the identifying letters in the
various hash preimages, and making sure to list the KEXINITs in the
right order)
- also in the SSH-2 transport layer, an if statement that controls
whether we send SERVICE_REQUEST and wait for SERVICE_ACCEPT, or
vice versa
- new ConnectionLayer methods for opening outgoing channels for X and
agent forwardings
- new functions in portfwd.c to establish listening sockets suitable
for remote-to-local port forwarding (i.e. not under the direction
of a Conf the way it's done on the client side).
2018-10-21 00:09:54 +03:00
|
|
|
strbuf *outgoing_kexinit, *incoming_kexinit;
|
|
|
|
strbuf *client_kexinit, *server_kexinit; /* aliases to the above */
|
Move client-specific SSH code into new files.
This is a major code reorganisation in preparation for making this
code base into one that can build an SSH server as well as a client.
(Mostly for purposes of using the server as a regression test suite
for the client, though I have some other possible uses in mind too.
However, it's currently no part of my plan to harden the server to the
point where it can sensibly be deployed in a hostile environment.)
In this preparatory commit, I've broken up the SSH-2 transport and
connection layers, and the SSH-1 connection layer, into multiple
source files, with each layer having its own header file containing
the shared type definitions. In each case, the new source file
contains code that's specific to the client side of the protocol, so
that a new file can be swapped in in its place when building the
server.
Mostly this is just a straightforward moving of code without changing
it very much, but there are a couple of actual changes in the process:
The parsing of SSH-2 global-request and channel open-messages is now
done by a new pair of functions in the client module. For channel
opens, I've invented a new union data type to be the return value from
that function, representing either failure (plus error message),
success (plus Channel instance to manage the new channel), or an
instruction to hand the channel over to a sharing downstream (plus a
pointer to the downstream in question).
Also, the tree234 of remote port forwardings in ssh2connection is now
initialised on first use by the client-specific code, so that's where
its compare function lives. The shared ssh2connection_free() still
takes responsibility for freeing it, but now has to check if it's
non-null first.
The outer shell of the ssh2_lportfwd_open method, for making a
local-to-remote port forwarding, is still centralised in
ssh2connection.c, but the part of it that actually constructs the
outgoing channel-open message has moved into the client code, because
that will have to change depending on whether the channel-open has to
have type direct-tcpip or forwarded-tcpip.
In the SSH-1 connection layer, half the filter_queue method has moved
out into the new client-specific code, but not all of it -
bidirectional channel maintenance messages are still handled
centrally. One exception is SSH_MSG_PORT_OPEN, which can be sent in
both directions, but with subtly different semantics - from server to
client, it's referring to a previously established remote forwarding
(and must be rejected if there isn't one that matches it), but from
client to server it's just a "direct-tcpip" request with no prior
context. So that one is in the client-specific module, and when I add
the server code it will have its own different handler.
2018-10-20 19:57:37 +03:00
|
|
|
int kex_init_value, kex_reply_value;
|
|
|
|
transport_direction in, out;
|
|
|
|
ptrlen hostkeydata, sigdata;
|
Add an actual SSH server program.
This server is NOT SECURE! If anyone is reading this commit message,
DO NOT DEPLOY IT IN A HOSTILE-FACING ENVIRONMENT! Its purpose is to
speak the server end of everything PuTTY speaks on the client side, so
that I can test that I haven't broken PuTTY when I reorganise its
code, even things like RSA key exchange or chained auth methods which
it's hard to find a server that speaks at all.
(For this reason, it's declared with [UT] in the Recipe file, so that
it falls into the same category as programs like testbn, which won't
be installed by 'make install'.)
Working title is 'Uppity', partly for 'Universal PuTTY Protocol
Interaction Test Yoke', but mostly because it looks quite like the
word 'PuTTY' with part of it reversed. (Apparently 'test yoke' is a
very rarely used term meaning something not altogether unlike 'test
harness', which is a bit of a stretch, but it'll do.)
It doesn't actually _support_ everything I want yet. At the moment,
it's a proof of concept only. But it has most of the machinery
present, and the parts it's missing - such as chained auth methods -
should be easy enough to add because I've built in the required
flexibility, in the form of an AuthPolicy object which can request
them if it wants to. However, the current AuthPolicy object is
entirely trivial, and will let in any user with the password "weasel".
(Another way in which this is not a production-ready server is that it
also has no interaction with the OS's authentication system. In
particular, it will not only let in any user with the same password,
but it won't even change uid - it will open shells and forwardings
under whatever user id you started it up as.)
Currently, the program can only speak the SSH protocol on its standard
I/O channels (using the new FdSocket facility), so if you want it to
listen on a network port, you'll have to run it from some kind of
separate listening program similar to inetd. For my own tests, I'm not
even doing that: I'm just having PuTTY spawn it as a local proxy
process, which also conveniently eliminates the risk of anyone hostile
connecting to it.
The bulk of the actual code reorganisation is already done by previous
commits, so this change is _mostly_ just dropping in a new set of
server-specific source files alongside the client-specific ones I
created recently. The remaining changes in the shared SSH code are
numerous, but all minor:
- a few extra parameters to BPP and PPL constructors (e.g. 'are you
in server mode?'), and pass both sets of SSH-1 protocol flags from
the login to the connection layer
- in server mode, unconditionally send our version string _before_
waiting for the remote one
- a new hook in the SSH-1 BPP to handle enabling compression in
server mode, where the message exchange works the other way round
- new code in the SSH-2 BPP to do _deferred_ compression the other
way round (the non-deferred version is still nicely symmetric)
- in the SSH-2 transport layer, some adjustments to do key derivation
either way round (swapping round the identifying letters in the
various hash preimages, and making sure to list the KEXINITs in the
right order)
- also in the SSH-2 transport layer, an if statement that controls
whether we send SERVICE_REQUEST and wait for SERVICE_ACCEPT, or
vice versa
- new ConnectionLayer methods for opening outgoing channels for X and
agent forwardings
- new functions in portfwd.c to establish listening sockets suitable
for remote-to-local port forwarding (i.e. not under the direction
of a Conf the way it's done on the client side).
2018-10-21 00:09:54 +03:00
|
|
|
strbuf *hostkeyblob;
|
Move client-specific SSH code into new files.
This is a major code reorganisation in preparation for making this
code base into one that can build an SSH server as well as a client.
(Mostly for purposes of using the server as a regression test suite
for the client, though I have some other possible uses in mind too.
However, it's currently no part of my plan to harden the server to the
point where it can sensibly be deployed in a hostile environment.)
In this preparatory commit, I've broken up the SSH-2 transport and
connection layers, and the SSH-1 connection layer, into multiple
source files, with each layer having its own header file containing
the shared type definitions. In each case, the new source file
contains code that's specific to the client side of the protocol, so
that a new file can be swapped in in its place when building the
server.
Mostly this is just a straightforward moving of code without changing
it very much, but there are a couple of actual changes in the process:
The parsing of SSH-2 global-request and channel open-messages is now
done by a new pair of functions in the client module. For channel
opens, I've invented a new union data type to be the return value from
that function, representing either failure (plus error message),
success (plus Channel instance to manage the new channel), or an
instruction to hand the channel over to a sharing downstream (plus a
pointer to the downstream in question).
Also, the tree234 of remote port forwardings in ssh2connection is now
initialised on first use by the client-specific code, so that's where
its compare function lives. The shared ssh2connection_free() still
takes responsibility for freeing it, but now has to check if it's
non-null first.
The outer shell of the ssh2_lportfwd_open method, for making a
local-to-remote port forwarding, is still centralised in
ssh2connection.c, but the part of it that actually constructs the
outgoing channel-open message has moved into the client code, because
that will have to change depending on whether the channel-open has to
have type direct-tcpip or forwarded-tcpip.
In the SSH-1 connection layer, half the filter_queue method has moved
out into the new client-specific code, but not all of it -
bidirectional channel maintenance messages are still handled
centrally. One exception is SSH_MSG_PORT_OPEN, which can be sent in
both directions, but with subtly different semantics - from server to
client, it's referring to a previously established remote forwarding
(and must be rejected if there isn't one that matches it), but from
client to server it's just a "direct-tcpip" request with no prior
context. So that one is in the client-specific module, and when I add
the server code it will have its own different handler.
2018-10-20 19:57:37 +03:00
|
|
|
char *keystr, *fingerprint;
|
|
|
|
ssh_key *hkey; /* actual host key */
|
|
|
|
struct RSAKey *rsa_kex_key; /* for RSA kex */
|
|
|
|
struct ec_key *ecdh_key; /* for ECDH kex */
|
|
|
|
unsigned char exchange_hash[SSH2_KEX_MAX_HASH_LEN];
|
Convert a lot of 'int' variables to 'bool'.
My normal habit these days, in new code, is to treat int and bool as
_almost_ completely separate types. I'm still willing to use C's
implicit test for zero on an integer (e.g. 'if (!blob.len)' is fine,
no need to spell it out as blob.len != 0), but generally, if a
variable is going to be conceptually a boolean, I like to declare it
bool and assign to it using 'true' or 'false' rather than 0 or 1.
PuTTY is an exception, because it predates the C99 bool, and I've
stuck to its existing coding style even when adding new code to it.
But it's been annoying me more and more, so now that I've decided C99
bool is an acceptable thing to require from our toolchain in the first
place, here's a quite thorough trawl through the source doing
'boolification'. Many variables and function parameters are now typed
as bool rather than int; many assignments of 0 or 1 to those variables
are now spelled 'true' or 'false'.
I managed this thorough conversion with the help of a custom clang
plugin that I wrote to trawl the AST and apply heuristics to point out
where things might want changing. So I've even managed to do a decent
job on parts of the code I haven't looked at in years!
To make the plugin's work easier, I pushed platform front ends
generally in the direction of using standard 'bool' in preference to
platform-specific boolean types like Windows BOOL or GTK's gboolean;
I've left the platform booleans in places they _have_ to be for the
platform APIs to work right, but variables only used by my own code
have been converted wherever I found them.
In a few places there are int values that look very like booleans in
_most_ of the places they're used, but have a rarely-used third value,
or a distinction between different nonzero values that most users
don't care about. In these cases, I've _removed_ uses of 'true' and
'false' for the return values, to emphasise that there's something
more subtle going on than a simple boolean answer:
- the 'multisel' field in dialog.h's list box structure, for which
the GTK front end in particular recognises a difference between 1
and 2 but nearly everything else treats as boolean
- the 'urgent' parameter to plug_receive, where 1 vs 2 tells you
something about the specific location of the urgent pointer, but
most clients only care about 0 vs 'something nonzero'
- the return value of wc_match, where -1 indicates a syntax error in
the wildcard.
- the return values from SSH-1 RSA-key loading functions, which use
-1 for 'wrong passphrase' and 0 for all other failures (so any
caller which already knows it's not loading an _encrypted private_
key can treat them as boolean)
- term->esc_query, and the 'query' parameter in toggle_mode in
terminal.c, which _usually_ hold 0 for ESC[123h or 1 for ESC[?123h,
but can also hold -1 for some other intervening character that we
don't support.
In a few places there's an integer that I haven't turned into a bool
even though it really _can_ only take values 0 or 1 (and, as above,
tried to make the call sites consistent in not calling those values
true and false), on the grounds that I thought it would make it more
confusing to imply that the 0 value was in some sense 'negative' or
bad and the 1 positive or good:
- the return value of plug_accepting uses the POSIXish convention of
0=success and nonzero=error; I think if I made it bool then I'd
also want to reverse its sense, and that's a job for a separate
piece of work.
- the 'screen' parameter to lineptr() in terminal.c, where 0 and 1
represent the default and alternate screens. There's no obvious
reason why one of those should be considered 'true' or 'positive'
or 'success' - they're just indices - so I've left it as int.
ssh_scp_recv had particularly confusing semantics for its previous int
return value: its call sites used '<= 0' to check for error, but it
never actually returned a negative number, just 0 or 1. Now the
function and its call sites agree that it's a bool.
In a couple of places I've renamed variables called 'ret', because I
don't like that name any more - it's unclear whether it means the
return value (in preparation) for the _containing_ function or the
return value received from a subroutine call, and occasionally I've
accidentally used the same variable for both and introduced a bug. So
where one of those got in my way, I've renamed it to 'toret' or 'retd'
(the latter short for 'returned') in line with my usual modern
practice, but I haven't done a thorough job of finding all of them.
Finally, one amusing side effect of doing this is that I've had to
separate quite a few chained assignments. It used to be perfectly fine
to write 'a = b = c = TRUE' when a,b,c were int and TRUE was just a
the 'true' defined by stdbool.h, that idiom provokes a warning from
gcc: 'suggest parentheses around assignment used as truth value'!
2018-11-02 22:23:19 +03:00
|
|
|
bool can_gssapi_keyex;
|
|
|
|
bool need_gss_transient_hostkey;
|
|
|
|
bool warned_about_no_gss_transient_hostkey;
|
|
|
|
bool got_session_id;
|
Move client-specific SSH code into new files.
This is a major code reorganisation in preparation for making this
code base into one that can build an SSH server as well as a client.
(Mostly for purposes of using the server as a regression test suite
for the client, though I have some other possible uses in mind too.
However, it's currently no part of my plan to harden the server to the
point where it can sensibly be deployed in a hostile environment.)
In this preparatory commit, I've broken up the SSH-2 transport and
connection layers, and the SSH-1 connection layer, into multiple
source files, with each layer having its own header file containing
the shared type definitions. In each case, the new source file
contains code that's specific to the client side of the protocol, so
that a new file can be swapped in in its place when building the
server.
Mostly this is just a straightforward moving of code without changing
it very much, but there are a couple of actual changes in the process:
The parsing of SSH-2 global-request and channel open-messages is now
done by a new pair of functions in the client module. For channel
opens, I've invented a new union data type to be the return value from
that function, representing either failure (plus error message),
success (plus Channel instance to manage the new channel), or an
instruction to hand the channel over to a sharing downstream (plus a
pointer to the downstream in question).
Also, the tree234 of remote port forwardings in ssh2connection is now
initialised on first use by the client-specific code, so that's where
its compare function lives. The shared ssh2connection_free() still
takes responsibility for freeing it, but now has to check if it's
non-null first.
The outer shell of the ssh2_lportfwd_open method, for making a
local-to-remote port forwarding, is still centralised in
ssh2connection.c, but the part of it that actually constructs the
outgoing channel-open message has moved into the client code, because
that will have to change depending on whether the channel-open has to
have type direct-tcpip or forwarded-tcpip.
In the SSH-1 connection layer, half the filter_queue method has moved
out into the new client-specific code, but not all of it -
bidirectional channel maintenance messages are still handled
centrally. One exception is SSH_MSG_PORT_OPEN, which can be sent in
both directions, but with subtly different semantics - from server to
client, it's referring to a previously established remote forwarding
(and must be rejected if there isn't one that matches it), but from
client to server it's just a "direct-tcpip" request with no prior
context. So that one is in the client-specific module, and when I add
the server code it will have its own different handler.
2018-10-20 19:57:37 +03:00
|
|
|
int dlgret;
|
Convert a lot of 'int' variables to 'bool'.
My normal habit these days, in new code, is to treat int and bool as
_almost_ completely separate types. I'm still willing to use C's
implicit test for zero on an integer (e.g. 'if (!blob.len)' is fine,
no need to spell it out as blob.len != 0), but generally, if a
variable is going to be conceptually a boolean, I like to declare it
bool and assign to it using 'true' or 'false' rather than 0 or 1.
PuTTY is an exception, because it predates the C99 bool, and I've
stuck to its existing coding style even when adding new code to it.
But it's been annoying me more and more, so now that I've decided C99
bool is an acceptable thing to require from our toolchain in the first
place, here's a quite thorough trawl through the source doing
'boolification'. Many variables and function parameters are now typed
as bool rather than int; many assignments of 0 or 1 to those variables
are now spelled 'true' or 'false'.
I managed this thorough conversion with the help of a custom clang
plugin that I wrote to trawl the AST and apply heuristics to point out
where things might want changing. So I've even managed to do a decent
job on parts of the code I haven't looked at in years!
To make the plugin's work easier, I pushed platform front ends
generally in the direction of using standard 'bool' in preference to
platform-specific boolean types like Windows BOOL or GTK's gboolean;
I've left the platform booleans in places they _have_ to be for the
platform APIs to work right, but variables only used by my own code
have been converted wherever I found them.
In a few places there are int values that look very like booleans in
_most_ of the places they're used, but have a rarely-used third value,
or a distinction between different nonzero values that most users
don't care about. In these cases, I've _removed_ uses of 'true' and
'false' for the return values, to emphasise that there's something
more subtle going on than a simple boolean answer:
- the 'multisel' field in dialog.h's list box structure, for which
the GTK front end in particular recognises a difference between 1
and 2 but nearly everything else treats as boolean
- the 'urgent' parameter to plug_receive, where 1 vs 2 tells you
something about the specific location of the urgent pointer, but
most clients only care about 0 vs 'something nonzero'
- the return value of wc_match, where -1 indicates a syntax error in
the wildcard.
- the return values from SSH-1 RSA-key loading functions, which use
-1 for 'wrong passphrase' and 0 for all other failures (so any
caller which already knows it's not loading an _encrypted private_
key can treat them as boolean)
- term->esc_query, and the 'query' parameter in toggle_mode in
terminal.c, which _usually_ hold 0 for ESC[123h or 1 for ESC[?123h,
but can also hold -1 for some other intervening character that we
don't support.
In a few places there's an integer that I haven't turned into a bool
even though it really _can_ only take values 0 or 1 (and, as above,
tried to make the call sites consistent in not calling those values
true and false), on the grounds that I thought it would make it more
confusing to imply that the 0 value was in some sense 'negative' or
bad and the 1 positive or good:
- the return value of plug_accepting uses the POSIXish convention of
0=success and nonzero=error; I think if I made it bool then I'd
also want to reverse its sense, and that's a job for a separate
piece of work.
- the 'screen' parameter to lineptr() in terminal.c, where 0 and 1
represent the default and alternate screens. There's no obvious
reason why one of those should be considered 'true' or 'positive'
or 'success' - they're just indices - so I've left it as int.
ssh_scp_recv had particularly confusing semantics for its previous int
return value: its call sites used '<= 0' to check for error, but it
never actually returned a negative number, just 0 or 1. Now the
function and its call sites agree that it's a bool.
In a couple of places I've renamed variables called 'ret', because I
don't like that name any more - it's unclear whether it means the
return value (in preparation) for the _containing_ function or the
return value received from a subroutine call, and occasionally I've
accidentally used the same variable for both and introduced a bug. So
where one of those got in my way, I've renamed it to 'toret' or 'retd'
(the latter short for 'returned') in line with my usual modern
practice, but I haven't done a thorough job of finding all of them.
Finally, one amusing side effect of doing this is that I've had to
separate quite a few chained assignments. It used to be perfectly fine
to write 'a = b = c = TRUE' when a,b,c were int and TRUE was just a
the 'true' defined by stdbool.h, that idiom provokes a warning from
gcc: 'suggest parentheses around assignment used as truth value'!
2018-11-02 22:23:19 +03:00
|
|
|
bool guessok;
|
|
|
|
bool ignorepkt;
|
Move client-specific SSH code into new files.
This is a major code reorganisation in preparation for making this
code base into one that can build an SSH server as well as a client.
(Mostly for purposes of using the server as a regression test suite
for the client, though I have some other possible uses in mind too.
However, it's currently no part of my plan to harden the server to the
point where it can sensibly be deployed in a hostile environment.)
In this preparatory commit, I've broken up the SSH-2 transport and
connection layers, and the SSH-1 connection layer, into multiple
source files, with each layer having its own header file containing
the shared type definitions. In each case, the new source file
contains code that's specific to the client side of the protocol, so
that a new file can be swapped in in its place when building the
server.
Mostly this is just a straightforward moving of code without changing
it very much, but there are a couple of actual changes in the process:
The parsing of SSH-2 global-request and channel open-messages is now
done by a new pair of functions in the client module. For channel
opens, I've invented a new union data type to be the return value from
that function, representing either failure (plus error message),
success (plus Channel instance to manage the new channel), or an
instruction to hand the channel over to a sharing downstream (plus a
pointer to the downstream in question).
Also, the tree234 of remote port forwardings in ssh2connection is now
initialised on first use by the client-specific code, so that's where
its compare function lives. The shared ssh2connection_free() still
takes responsibility for freeing it, but now has to check if it's
non-null first.
The outer shell of the ssh2_lportfwd_open method, for making a
local-to-remote port forwarding, is still centralised in
ssh2connection.c, but the part of it that actually constructs the
outgoing channel-open message has moved into the client code, because
that will have to change depending on whether the channel-open has to
have type direct-tcpip or forwarded-tcpip.
In the SSH-1 connection layer, half the filter_queue method has moved
out into the new client-specific code, but not all of it -
bidirectional channel maintenance messages are still handled
centrally. One exception is SSH_MSG_PORT_OPEN, which can be sent in
both directions, but with subtly different semantics - from server to
client, it's referring to a previously established remote forwarding
(and must be rejected if there isn't one that matches it), but from
client to server it's just a "direct-tcpip" request with no prior
context. So that one is in the client-specific module, and when I add
the server code it will have its own different handler.
2018-10-20 19:57:37 +03:00
|
|
|
struct kexinit_algorithm kexlists[NKEXLIST][MAXKEXLIST];
|
|
|
|
#ifndef NO_GSSAPI
|
|
|
|
Ssh_gss_buf gss_buf;
|
|
|
|
Ssh_gss_buf gss_rcvtok, gss_sndtok;
|
|
|
|
Ssh_gss_stat gss_stat;
|
|
|
|
Ssh_gss_buf mic;
|
Convert a lot of 'int' variables to 'bool'.
My normal habit these days, in new code, is to treat int and bool as
_almost_ completely separate types. I'm still willing to use C's
implicit test for zero on an integer (e.g. 'if (!blob.len)' is fine,
no need to spell it out as blob.len != 0), but generally, if a
variable is going to be conceptually a boolean, I like to declare it
bool and assign to it using 'true' or 'false' rather than 0 or 1.
PuTTY is an exception, because it predates the C99 bool, and I've
stuck to its existing coding style even when adding new code to it.
But it's been annoying me more and more, so now that I've decided C99
bool is an acceptable thing to require from our toolchain in the first
place, here's a quite thorough trawl through the source doing
'boolification'. Many variables and function parameters are now typed
as bool rather than int; many assignments of 0 or 1 to those variables
are now spelled 'true' or 'false'.
I managed this thorough conversion with the help of a custom clang
plugin that I wrote to trawl the AST and apply heuristics to point out
where things might want changing. So I've even managed to do a decent
job on parts of the code I haven't looked at in years!
To make the plugin's work easier, I pushed platform front ends
generally in the direction of using standard 'bool' in preference to
platform-specific boolean types like Windows BOOL or GTK's gboolean;
I've left the platform booleans in places they _have_ to be for the
platform APIs to work right, but variables only used by my own code
have been converted wherever I found them.
In a few places there are int values that look very like booleans in
_most_ of the places they're used, but have a rarely-used third value,
or a distinction between different nonzero values that most users
don't care about. In these cases, I've _removed_ uses of 'true' and
'false' for the return values, to emphasise that there's something
more subtle going on than a simple boolean answer:
- the 'multisel' field in dialog.h's list box structure, for which
the GTK front end in particular recognises a difference between 1
and 2 but nearly everything else treats as boolean
- the 'urgent' parameter to plug_receive, where 1 vs 2 tells you
something about the specific location of the urgent pointer, but
most clients only care about 0 vs 'something nonzero'
- the return value of wc_match, where -1 indicates a syntax error in
the wildcard.
- the return values from SSH-1 RSA-key loading functions, which use
-1 for 'wrong passphrase' and 0 for all other failures (so any
caller which already knows it's not loading an _encrypted private_
key can treat them as boolean)
- term->esc_query, and the 'query' parameter in toggle_mode in
terminal.c, which _usually_ hold 0 for ESC[123h or 1 for ESC[?123h,
but can also hold -1 for some other intervening character that we
don't support.
In a few places there's an integer that I haven't turned into a bool
even though it really _can_ only take values 0 or 1 (and, as above,
tried to make the call sites consistent in not calling those values
true and false), on the grounds that I thought it would make it more
confusing to imply that the 0 value was in some sense 'negative' or
bad and the 1 positive or good:
- the return value of plug_accepting uses the POSIXish convention of
0=success and nonzero=error; I think if I made it bool then I'd
also want to reverse its sense, and that's a job for a separate
piece of work.
- the 'screen' parameter to lineptr() in terminal.c, where 0 and 1
represent the default and alternate screens. There's no obvious
reason why one of those should be considered 'true' or 'positive'
or 'success' - they're just indices - so I've left it as int.
ssh_scp_recv had particularly confusing semantics for its previous int
return value: its call sites used '<= 0' to check for error, but it
never actually returned a negative number, just 0 or 1. Now the
function and its call sites agree that it's a bool.
In a couple of places I've renamed variables called 'ret', because I
don't like that name any more - it's unclear whether it means the
return value (in preparation) for the _containing_ function or the
return value received from a subroutine call, and occasionally I've
accidentally used the same variable for both and introduced a bug. So
where one of those got in my way, I've renamed it to 'toret' or 'retd'
(the latter short for 'returned') in line with my usual modern
practice, but I haven't done a thorough job of finding all of them.
Finally, one amusing side effect of doing this is that I've had to
separate quite a few chained assignments. It used to be perfectly fine
to write 'a = b = c = TRUE' when a,b,c were int and TRUE was just a
the 'true' defined by stdbool.h, that idiom provokes a warning from
gcc: 'suggest parentheses around assignment used as truth value'!
2018-11-02 22:23:19 +03:00
|
|
|
bool init_token_sent;
|
|
|
|
bool complete_rcvd;
|
|
|
|
bool gss_delegate;
|
Move client-specific SSH code into new files.
This is a major code reorganisation in preparation for making this
code base into one that can build an SSH server as well as a client.
(Mostly for purposes of using the server as a regression test suite
for the client, though I have some other possible uses in mind too.
However, it's currently no part of my plan to harden the server to the
point where it can sensibly be deployed in a hostile environment.)
In this preparatory commit, I've broken up the SSH-2 transport and
connection layers, and the SSH-1 connection layer, into multiple
source files, with each layer having its own header file containing
the shared type definitions. In each case, the new source file
contains code that's specific to the client side of the protocol, so
that a new file can be swapped in in its place when building the
server.
Mostly this is just a straightforward moving of code without changing
it very much, but there are a couple of actual changes in the process:
The parsing of SSH-2 global-request and channel open-messages is now
done by a new pair of functions in the client module. For channel
opens, I've invented a new union data type to be the return value from
that function, representing either failure (plus error message),
success (plus Channel instance to manage the new channel), or an
instruction to hand the channel over to a sharing downstream (plus a
pointer to the downstream in question).
Also, the tree234 of remote port forwardings in ssh2connection is now
initialised on first use by the client-specific code, so that's where
its compare function lives. The shared ssh2connection_free() still
takes responsibility for freeing it, but now has to check if it's
non-null first.
The outer shell of the ssh2_lportfwd_open method, for making a
local-to-remote port forwarding, is still centralised in
ssh2connection.c, but the part of it that actually constructs the
outgoing channel-open message has moved into the client code, because
that will have to change depending on whether the channel-open has to
have type direct-tcpip or forwarded-tcpip.
In the SSH-1 connection layer, half the filter_queue method has moved
out into the new client-specific code, but not all of it -
bidirectional channel maintenance messages are still handled
centrally. One exception is SSH_MSG_PORT_OPEN, which can be sent in
both directions, but with subtly different semantics - from server to
client, it's referring to a previously established remote forwarding
(and must be rejected if there isn't one that matches it), but from
client to server it's just a "direct-tcpip" request with no prior
context. So that one is in the client-specific module, and when I add
the server code it will have its own different handler.
2018-10-20 19:57:37 +03:00
|
|
|
#endif
|
|
|
|
|
|
|
|
/*
|
|
|
|
* List of host key algorithms for which we _don't_ have a stored
|
|
|
|
* host key. These are indices into the main hostkey_algs[] array
|
|
|
|
*/
|
|
|
|
int uncert_hostkeys[N_HOSTKEY_ALGORITHMS];
|
|
|
|
int n_uncert_hostkeys;
|
|
|
|
|
|
|
|
/*
|
2018-12-01 17:39:23 +03:00
|
|
|
* Indicate that the current rekey is intended to finish with a
|
|
|
|
* newly cross-certified host key. To double-check that we
|
|
|
|
* certified the right one, we set this to point to the host key
|
|
|
|
* algorithm we expect it to be.
|
Move client-specific SSH code into new files.
This is a major code reorganisation in preparation for making this
code base into one that can build an SSH server as well as a client.
(Mostly for purposes of using the server as a regression test suite
for the client, though I have some other possible uses in mind too.
However, it's currently no part of my plan to harden the server to the
point where it can sensibly be deployed in a hostile environment.)
In this preparatory commit, I've broken up the SSH-2 transport and
connection layers, and the SSH-1 connection layer, into multiple
source files, with each layer having its own header file containing
the shared type definitions. In each case, the new source file
contains code that's specific to the client side of the protocol, so
that a new file can be swapped in in its place when building the
server.
Mostly this is just a straightforward moving of code without changing
it very much, but there are a couple of actual changes in the process:
The parsing of SSH-2 global-request and channel open-messages is now
done by a new pair of functions in the client module. For channel
opens, I've invented a new union data type to be the return value from
that function, representing either failure (plus error message),
success (plus Channel instance to manage the new channel), or an
instruction to hand the channel over to a sharing downstream (plus a
pointer to the downstream in question).
Also, the tree234 of remote port forwardings in ssh2connection is now
initialised on first use by the client-specific code, so that's where
its compare function lives. The shared ssh2connection_free() still
takes responsibility for freeing it, but now has to check if it's
non-null first.
The outer shell of the ssh2_lportfwd_open method, for making a
local-to-remote port forwarding, is still centralised in
ssh2connection.c, but the part of it that actually constructs the
outgoing channel-open message has moved into the client code, because
that will have to change depending on whether the channel-open has to
have type direct-tcpip or forwarded-tcpip.
In the SSH-1 connection layer, half the filter_queue method has moved
out into the new client-specific code, but not all of it -
bidirectional channel maintenance messages are still handled
centrally. One exception is SSH_MSG_PORT_OPEN, which can be sent in
both directions, but with subtly different semantics - from server to
client, it's referring to a previously established remote forwarding
(and must be rejected if there isn't one that matches it), but from
client to server it's just a "direct-tcpip" request with no prior
context. So that one is in the client-specific module, and when I add
the server code it will have its own different handler.
2018-10-20 19:57:37 +03:00
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*/
|
2018-12-01 17:39:23 +03:00
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const ssh_keyalg *cross_certifying;
|
Move client-specific SSH code into new files.
This is a major code reorganisation in preparation for making this
code base into one that can build an SSH server as well as a client.
(Mostly for purposes of using the server as a regression test suite
for the client, though I have some other possible uses in mind too.
However, it's currently no part of my plan to harden the server to the
point where it can sensibly be deployed in a hostile environment.)
In this preparatory commit, I've broken up the SSH-2 transport and
connection layers, and the SSH-1 connection layer, into multiple
source files, with each layer having its own header file containing
the shared type definitions. In each case, the new source file
contains code that's specific to the client side of the protocol, so
that a new file can be swapped in in its place when building the
server.
Mostly this is just a straightforward moving of code without changing
it very much, but there are a couple of actual changes in the process:
The parsing of SSH-2 global-request and channel open-messages is now
done by a new pair of functions in the client module. For channel
opens, I've invented a new union data type to be the return value from
that function, representing either failure (plus error message),
success (plus Channel instance to manage the new channel), or an
instruction to hand the channel over to a sharing downstream (plus a
pointer to the downstream in question).
Also, the tree234 of remote port forwardings in ssh2connection is now
initialised on first use by the client-specific code, so that's where
its compare function lives. The shared ssh2connection_free() still
takes responsibility for freeing it, but now has to check if it's
non-null first.
The outer shell of the ssh2_lportfwd_open method, for making a
local-to-remote port forwarding, is still centralised in
ssh2connection.c, but the part of it that actually constructs the
outgoing channel-open message has moved into the client code, because
that will have to change depending on whether the channel-open has to
have type direct-tcpip or forwarded-tcpip.
In the SSH-1 connection layer, half the filter_queue method has moved
out into the new client-specific code, but not all of it -
bidirectional channel maintenance messages are still handled
centrally. One exception is SSH_MSG_PORT_OPEN, which can be sent in
both directions, but with subtly different semantics - from server to
client, it's referring to a previously established remote forwarding
(and must be rejected if there isn't one that matches it), but from
client to server it's just a "direct-tcpip" request with no prior
context. So that one is in the client-specific module, and when I add
the server code it will have its own different handler.
2018-10-20 19:57:37 +03:00
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|
Add an actual SSH server program.
This server is NOT SECURE! If anyone is reading this commit message,
DO NOT DEPLOY IT IN A HOSTILE-FACING ENVIRONMENT! Its purpose is to
speak the server end of everything PuTTY speaks on the client side, so
that I can test that I haven't broken PuTTY when I reorganise its
code, even things like RSA key exchange or chained auth methods which
it's hard to find a server that speaks at all.
(For this reason, it's declared with [UT] in the Recipe file, so that
it falls into the same category as programs like testbn, which won't
be installed by 'make install'.)
Working title is 'Uppity', partly for 'Universal PuTTY Protocol
Interaction Test Yoke', but mostly because it looks quite like the
word 'PuTTY' with part of it reversed. (Apparently 'test yoke' is a
very rarely used term meaning something not altogether unlike 'test
harness', which is a bit of a stretch, but it'll do.)
It doesn't actually _support_ everything I want yet. At the moment,
it's a proof of concept only. But it has most of the machinery
present, and the parts it's missing - such as chained auth methods -
should be easy enough to add because I've built in the required
flexibility, in the form of an AuthPolicy object which can request
them if it wants to. However, the current AuthPolicy object is
entirely trivial, and will let in any user with the password "weasel".
(Another way in which this is not a production-ready server is that it
also has no interaction with the OS's authentication system. In
particular, it will not only let in any user with the same password,
but it won't even change uid - it will open shells and forwardings
under whatever user id you started it up as.)
Currently, the program can only speak the SSH protocol on its standard
I/O channels (using the new FdSocket facility), so if you want it to
listen on a network port, you'll have to run it from some kind of
separate listening program similar to inetd. For my own tests, I'm not
even doing that: I'm just having PuTTY spawn it as a local proxy
process, which also conveniently eliminates the risk of anyone hostile
connecting to it.
The bulk of the actual code reorganisation is already done by previous
commits, so this change is _mostly_ just dropping in a new set of
server-specific source files alongside the client-specific ones I
created recently. The remaining changes in the shared SSH code are
numerous, but all minor:
- a few extra parameters to BPP and PPL constructors (e.g. 'are you
in server mode?'), and pass both sets of SSH-1 protocol flags from
the login to the connection layer
- in server mode, unconditionally send our version string _before_
waiting for the remote one
- a new hook in the SSH-1 BPP to handle enabling compression in
server mode, where the message exchange works the other way round
- new code in the SSH-2 BPP to do _deferred_ compression the other
way round (the non-deferred version is still nicely symmetric)
- in the SSH-2 transport layer, some adjustments to do key derivation
either way round (swapping round the identifying letters in the
various hash preimages, and making sure to list the KEXINITs in the
right order)
- also in the SSH-2 transport layer, an if statement that controls
whether we send SERVICE_REQUEST and wait for SERVICE_ACCEPT, or
vice versa
- new ConnectionLayer methods for opening outgoing channels for X and
agent forwardings
- new functions in portfwd.c to establish listening sockets suitable
for remote-to-local port forwarding (i.e. not under the direction
of a Conf the way it's done on the client side).
2018-10-21 00:09:54 +03:00
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ssh_key *const *hostkeys;
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int nhostkeys;
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|
Move client-specific SSH code into new files.
This is a major code reorganisation in preparation for making this
code base into one that can build an SSH server as well as a client.
(Mostly for purposes of using the server as a regression test suite
for the client, though I have some other possible uses in mind too.
However, it's currently no part of my plan to harden the server to the
point where it can sensibly be deployed in a hostile environment.)
In this preparatory commit, I've broken up the SSH-2 transport and
connection layers, and the SSH-1 connection layer, into multiple
source files, with each layer having its own header file containing
the shared type definitions. In each case, the new source file
contains code that's specific to the client side of the protocol, so
that a new file can be swapped in in its place when building the
server.
Mostly this is just a straightforward moving of code without changing
it very much, but there are a couple of actual changes in the process:
The parsing of SSH-2 global-request and channel open-messages is now
done by a new pair of functions in the client module. For channel
opens, I've invented a new union data type to be the return value from
that function, representing either failure (plus error message),
success (plus Channel instance to manage the new channel), or an
instruction to hand the channel over to a sharing downstream (plus a
pointer to the downstream in question).
Also, the tree234 of remote port forwardings in ssh2connection is now
initialised on first use by the client-specific code, so that's where
its compare function lives. The shared ssh2connection_free() still
takes responsibility for freeing it, but now has to check if it's
non-null first.
The outer shell of the ssh2_lportfwd_open method, for making a
local-to-remote port forwarding, is still centralised in
ssh2connection.c, but the part of it that actually constructs the
outgoing channel-open message has moved into the client code, because
that will have to change depending on whether the channel-open has to
have type direct-tcpip or forwarded-tcpip.
In the SSH-1 connection layer, half the filter_queue method has moved
out into the new client-specific code, but not all of it -
bidirectional channel maintenance messages are still handled
centrally. One exception is SSH_MSG_PORT_OPEN, which can be sent in
both directions, but with subtly different semantics - from server to
client, it's referring to a previously established remote forwarding
(and must be rejected if there isn't one that matches it), but from
client to server it's just a "direct-tcpip" request with no prior
context. So that one is in the client-specific module, and when I add
the server code it will have its own different handler.
2018-10-20 19:57:37 +03:00
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PacketProtocolLayer ppl;
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};
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/* Helpers shared between transport and kex */
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PktIn *ssh2_transport_pop(struct ssh2_transport_state *s);
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void ssh2_transport_dialog_callback(void *, int);
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/* Provided by transport for use in kex */
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void ssh2transport_finalise_exhash(struct ssh2_transport_state *s);
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2018-12-29 15:00:03 +03:00
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/* Provided by kex for use in transport. Must set the 'aborted' flag
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* if it throws a connection-terminating error, so that the caller
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* won't have to check that by looking inside its state parameter
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* which might already have been freed. */
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void ssh2kex_coroutine(struct ssh2_transport_state *s, bool *aborted);
|
Move client-specific SSH code into new files.
This is a major code reorganisation in preparation for making this
code base into one that can build an SSH server as well as a client.
(Mostly for purposes of using the server as a regression test suite
for the client, though I have some other possible uses in mind too.
However, it's currently no part of my plan to harden the server to the
point where it can sensibly be deployed in a hostile environment.)
In this preparatory commit, I've broken up the SSH-2 transport and
connection layers, and the SSH-1 connection layer, into multiple
source files, with each layer having its own header file containing
the shared type definitions. In each case, the new source file
contains code that's specific to the client side of the protocol, so
that a new file can be swapped in in its place when building the
server.
Mostly this is just a straightforward moving of code without changing
it very much, but there are a couple of actual changes in the process:
The parsing of SSH-2 global-request and channel open-messages is now
done by a new pair of functions in the client module. For channel
opens, I've invented a new union data type to be the return value from
that function, representing either failure (plus error message),
success (plus Channel instance to manage the new channel), or an
instruction to hand the channel over to a sharing downstream (plus a
pointer to the downstream in question).
Also, the tree234 of remote port forwardings in ssh2connection is now
initialised on first use by the client-specific code, so that's where
its compare function lives. The shared ssh2connection_free() still
takes responsibility for freeing it, but now has to check if it's
non-null first.
The outer shell of the ssh2_lportfwd_open method, for making a
local-to-remote port forwarding, is still centralised in
ssh2connection.c, but the part of it that actually constructs the
outgoing channel-open message has moved into the client code, because
that will have to change depending on whether the channel-open has to
have type direct-tcpip or forwarded-tcpip.
In the SSH-1 connection layer, half the filter_queue method has moved
out into the new client-specific code, but not all of it -
bidirectional channel maintenance messages are still handled
centrally. One exception is SSH_MSG_PORT_OPEN, which can be sent in
both directions, but with subtly different semantics - from server to
client, it's referring to a previously established remote forwarding
(and must be rejected if there isn't one that matches it), but from
client to server it's just a "direct-tcpip" request with no prior
context. So that one is in the client-specific module, and when I add
the server code it will have its own different handler.
2018-10-20 19:57:37 +03:00
|
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#endif /* PUTTY_SSH2TRANSPORT_H */
|