Now bugs that are still likely to come up with relatively recent
server software (because they're only a few years fixed, or because
they're the sort of mistake that new server implementors will likely
make again) are in the Bugs panel, and very old things long since
fixed are relegated to More Bugs.
In particular, More Bugs contains everything SSH-1 related.
The UI now only has "1" and "2" options for SSH protocol version, which
behave like the old "1 only" and "2 only" options; old
SSH-N-with-fallback settings are interpreted as SSH-N-only.
This prevents any attempt at a protocol downgrade attack.
Most users should see no difference; those poor souls who still have to
work with SSH-1 equipment now have to explicitly opt in.
Now we actually have enough of them to worry about, and especially
since some of the types we support are approved by organisations that
people might make their own decisions about whether to trust, it seems
worth having a config list for host keys the same way we have one for
kex types and ciphers.
To make room for this, I've created an SSH > Host Keys config panel,
and moved the existing host-key related configuration (manually
specified fingerprints) into there from the Kex panel.
It's too esoteric to be the first thing on the Auth panel; I've never
heard of any SSH server that supports it in the decade since I
implemented it. The only Google hits are lost souls mistakenly believing
they need it for passwordless public-key login and the like.
It has three settings: on, off, and 'only until session starts'. The
idea of the last one is that if you use something like 'ssh -v' as
your proxy command, you probably wanted to see the initial SSH
connection-setup messages while you were waiting to see if the
connection would be set up successfully at all, but probably _didn't_
want a slew of diagnostics from rekeys disrupting your terminal in
mid-emacs once the session had got properly under way.
Default is off, to avoid startling people used to the old behaviour. I
wonder if I should have set it more aggressively, though.
Users have requested this from time to time, for distinguishing log
file names when there's more than one SSH server running on different
ports of the same host. Since we do take account of that possibility
in other areas (e.g. we cache host keys indexed by (host,port) rather
than just host), it doesn't seem unreasonable to do so here too.
Having found a lot of unfixed constness issues in recent development,
I thought perhaps it was time to get proactive, so I compiled the
whole codebase with -Wwrite-strings. That turned up a huge load of
const problems, which I've fixed in this commit: the Unix build now
goes cleanly through with -Wwrite-strings, and the Windows build is as
close as I could get it (there are some lingering issues due to
occasional Windows API functions like AcquireCredentialsHandle not
having the right constness).
Notable fallout beyond the purely mechanical changing of types:
- the stuff saved by cmdline_save_param() is now explicitly
dupstr()ed, and freed in cmdline_run_saved.
- I couldn't make both string arguments to cmdline_process_param()
const, because it intentionally writes to one of them in the case
where it's the argument to -pw (in the vain hope of being at least
slightly friendly to 'ps'), so elsewhere I had to temporarily
dupstr() something for the sake of passing it to that function
- I had to invent a silly parallel version of const_cmp() so I could
pass const string literals in to lookup functions.
- stripslashes() in pscp.c and psftp.c has the annoying strchr nature
The memory dangling off ssd->sesslist should be freed when ssd itself
goes away, and the font settings ctrlset we delete in gtkcfg.c should
be freed as well once it's been removed from its containing array.
Thanks to Ranjini Aravind for pointing these out.
PuTTY now uses the updated version of Diffie-Hellman group exchange,
except for a few old OpenSSH versions which Darren Tucker reports only
support the old version.
FIXME: this needs further work because the Bugs config panel has now
overflowed.
Changing it can't have any useful effect, since we have strictly
enforced that the host key used for rekeys is the same as the first key
exchange since b8e668c.
This provides support for ECDSA public keys, for both hosts and users,
and also ECDH key exchange. Supported curves are currently just the
three NIST curves required by RFC 5656.
This option is available from the command line as '-hostkey', and is
also configurable through the GUI. When enabled, it completely
replaces all of the automated host key management: the server's host
key will be checked against the manually configured list, and the
connection will be allowed or disconnected on that basis, and the host
key store in the registry will not be either consulted or updated.
The main aim is to provide a means of automatically running Plink,
PSCP or PSFTP deep inside Windows services where HKEY_CURRENT_USER
isn't available to have stored the right host key in. But it also
permits you to specify a list of multiple host keys, which means a
second use case for the same mechanism will probably be round-robin
DNS names that select one of several servers with different host keys.
Host keys can be specified as the standard MD5 fingerprint or as an
SSH-2 base64 blob, and are canonicalised on input. (The base64 blob is
more unwieldy, especially with Windows command-line length limits, but
provides a means of specifying the _whole_ public key in case you
don't trust MD5. I haven't bothered to provide an analogous mechanism
for SSH-1, on the basis that anyone worrying about MD5 should have
stopped using SSH-1 already!)
[originally from svn r10220]
We now expect that after the server has sent us CHANNEL_CLOSE, we
should not expect to see any replies to our outstanding channel
requests, and conversely after we have sent CHANNEL_CLOSE we avoid
sending any reply to channel requests from the server. This was the
consensus among implementors discussing the problem on ietf-ssh in
April 2014.
To cope with current OpenSSH's (and perhaps other servers we don't
know about yet) willingness to send request replies after
CHANNEL_CLOSE, I introduce a bug-compatibility flag which is detected
for every OpenSSH version up to and including the current 6.6 - but
not beyond, since https://bugzilla.mindrot.org/show_bug.cgi?id=1818
promises that 6.7 will also implement the new consensus behaviour.
[originally from svn r10200]
A user pointed out that 'family' was uninitialised in config.c, and
when I tried test-building with -DNO_IPV6 (and the usual -Werror, of
course) some unused variables showed up in uxnet.c too.
[originally from svn r10135]
I've gone through everywhere we handle host names / addresses (on
command lines, in PuTTY config, in port forwarding, in X display
names, in host key storage...) and tried to make them handle IPv6
literals sensibly, by using the host_str* functions I introduced in my
previous commit. Generally it's now OK to use a bracketed IPv6 literal
anywhere a hostname might have been valid; in a few cases where no
ambiguity exists (e.g. no :port suffix is permitted anyway)
unbracketed IPv6 literals are also acceptable.
[originally from svn r10120]
The basic strategy is described at the top of the new source file
sshshare.c. In very brief: an 'upstream' PuTTY opens a Unix-domain
socket or Windows named pipe, and listens for connections from other
PuTTYs wanting to run sessions on the same server. The protocol spoken
down that socket/pipe is essentially the bare ssh-connection protocol,
using a trivial binary packet protocol with no encryption, and the
upstream has to do some fiddly transformations that I've been
referring to as 'channel-number NAT' to avoid resource clashes between
the sessions it's managing.
This is quite different from OpenSSH's approach of using the Unix-
domain socket as a means of passing file descriptors around; the main
reason for that is that fd-passing is Unix-specific but this system
has to work on Windows too. However, there are additional advantages,
such as making it easy for each downstream PuTTY to run its own
independent set of port and X11 forwardings (though the method for
making the latter work is quite painful).
Sharing is off by default, but configuration is intended to be very
easy in the normal case - just tick one box in the SSH config panel
and everything else happens automatically.
[originally from svn r10083]
During the Conf revamp, I changed the internal representation of
dynamic forwardings so that they were stored as the conceptually
sensible L12345=D rather than the old D12345, and added compensation
code to translate to the latter form for backwards-compatible data
storage and for OpenSSH-harmonised GUI display. Unfortunately I forgot
that keys in the forwarding data can also prefix the L/R with a
character indicating IPv4/IPv6, and my translations didn't take
account of that possibility. Fix them.
[originally from svn r10031]
the session saving code, in which the contents of the edit box giving
the current saved session name was stored in a horrid place with a
fixed length. Now it's dangling off sessionsaver_data as it always
ought to have been, and it's dynamically reallocated to the
appropriate length, and there's a free function that cleans it up at
the end of the dialog's lifetime.
[originally from svn r9923]
winadj@putty.projects.tartarus.org request. Not currently enabled
automatically, but should be usable as a manual workaround.
[originally from svn r9592]
wonky because I'd used the subkey for the red component in four places
where I should have used the green/blue subkeys instead. Thanks to
Martin Kletzander for spotting it.
[originally from svn r9449]
[r9214 == a1f3b7a358]
allocated type.
The main reason for this is to stop it from taking up a fixed large
amount of space in every 'struct value' subunion in conf.c, although
that makes little difference so far because Filename is still doing
the same thing (and is therefore next on my list). However, the
removal of its arbitrary length limit is not to be sneezed at.
[originally from svn r9314]
'Config' in putty.h, which stores all PuTTY's settings and includes an
arbitrary length limit on every single one of those settings which is
stored in string form. In place of it is 'Conf', an opaque data type
everywhere outside the new file conf.c, which stores a list of (key,
value) pairs in which every key contains an integer identifying a
configuration setting, and for some of those integers the key also
contains extra parts (so that, for instance, CONF_environmt is a
string-to-string mapping). Everywhere that a Config was previously
used, a Conf is now; everywhere there was a Config structure copy,
conf_copy() is called; every lookup, adjustment, load and save
operation on a Config has been rewritten; and there's a mechanism for
serialising a Conf into a binary blob and back for use with Duplicate
Session.
User-visible effects of this change _should_ be minimal, though I
don't doubt I've introduced one or two bugs here and there which will
eventually be found. The _intended_ visible effects of this change are
that all arbitrary limits on configuration strings and lists (e.g.
limit on number of port forwardings) should now disappear; that list
boxes in the configuration will now be displayed in a sorted order
rather than the arbitrary order in which they were added to the list
(since the underlying data structure is now a sorted tree234 rather
than an ad-hoc comma-separated string); and one more specific change,
which is that local and dynamic port forwardings on the same port
number are now mutually exclusive in the configuration (putting 'D' in
the key rather than the value was a mistake in the first place).
One other reorganisation as a result of this is that I've moved all
the dialog.c standard handlers (dlg_stdeditbox_handler and friends)
out into config.c, because I can't really justify calling them generic
any more. When they took a pointer to an arbitrary structure type and
the offset of a field within that structure, they were independent of
whether that structure was a Config or something completely different,
but now they really do expect to talk to a Conf, which can _only_ be
used for PuTTY configuration, so I've renamed them all things like
conf_editbox_handler and moved them out of the nominally independent
dialog-box management module into the PuTTY-specific config.c.
[originally from svn r9214]
and avoiding trashing a non-default port, don't treat a port of 0 as special;
this was causing defaults to "freeze in" for sequences of clicks like SSH,
Raw, Telnet.
Arrange that a port of 0 (which in a backend indicates no default) is displayed
as a blank in the port box, to make this less jarring.
[originally from svn r9077]
[r7635 == db7cc1cba6]
are now loaded from standard locations (system32 for SSPI, the
registry-stored MIT KfW install location for KfW) rather than using
the risky default DLL search path; I've therefore also added an
option to manually specify a GSS DLL we haven't heard of (which
should in principle Just Work provided it supports proper GSS-API as
specified in the RFC). The same option exists on Unix too, because
it seemed like too useful an idea to reserve to Windows. In
addition, GSSAPI is now documented, and also (unfortunately) its GUI
configuration has been moved out into a sub-subpanel on the grounds
that it was too big to fit in Auth.
[originally from svn r9003]
reorganises the GSSAPI support so that it handles alternative
implementations of the GSS-API. In particular, this means PuTTY can
now talk to MIT Kerberos for Windows instead of being limited to
SSPI. I don't know for sure whether further tweaking will be needed
(to the UI, most likely, or to automatic selection of credentials),
but testing reports suggest it's now at least worth committing to
trunk to get it more widely tested.
[originally from svn r8952]
today reported an SSH2_MSG_UNIMPLEMENTED from a Cisco router which
looks as if it was triggered by SSH2_MSG_IGNORE, so I'm
experimentally putting this flag in. Currently must be manually
enabled, though if it turns out to solve the user's problem then
I'll probably add at least one version string...
[Edited commit message: actually, I also committed in error a piece
of experimental code as part of this checkin. Serve me right for not
running 'svn diff' first.]
[originally from svn r8926]
NameUserPrincipal, use that; this avoids an issue with SSPI/GSSAPI where
the user logged in to the local machine with a different case of username
to the (case-sensitive) Kerberos username. Falls back to GetUserName as
before if that doesn't work (for machines not on a domain, and Win9x).
Based on a patch by SebastianUnger.
[originally from svn r8909]
re-entrant call to its handler in config.c, which destroys the
previous value in cfg->line_codepage. Therefore, preserve the right
value in an automatic variable until all the re-entrant calls have
finished.
[originally from svn r8592]
While I'm here, a cosmetic PuTTYtel change: remove a reference to SSH from the
"logical host name" label in PuTTYtel only.
[originally from svn r8331]
[r8305 == ca6fc3a4da]
if we have no better ideas, with UI shamelessly stolen from Quest PuTTY.
Off by default, which effectively reverts the change to using the local
username by default that came in with GSSAPI support in r8138. Anyone wanting
seamless single sign-on will need to set the new option. (The previous
default behaviour was getting in the way in ad-hoc scenarios.)
Note that the PSCP and Unix-Plink behaviour of using the local username by
default have remained unchanged throughout; they are not affected by the new
option. Not sure if that's the Right Thing.
[originally from svn r8324]
[r8138 == de5dd9d65c]
on received data. Experiment and suggestion suggest that the character set
configuration applies equally to keystrokes sent to the server, or at least
that that's close enough to being true that we should document it as a first
approximation.
[originally from svn r8209]
Simon Tatham
Jacob Nevins
Chris Staite