This reverts commit 72b006f4bf, which
breaks the end-user experience when merging a signed tag without
having the public key. We should report "can't check because we
have no public key", but the code with this change claimed that
there was no signature.
This commit refactors the use of verify_signed_buffer() outside of
gpg-interface.c to use check_signature() instead. It also turns
verify_signed_buffer() into a file-local function since it's now only
invoked internally by check_signature().
There were previously two globally scoped functions used in different
parts of Git to perform GPG signature verification:
verify_signed_buffer() and check_signature(). Now only
check_signature() is used.
The verify_signed_buffer() function doesn't guard against duplicate
signatures as described by Michał Górny [1]. Instead it only ensures a
non-erroneous exit code from GPG and the presence of at least one
GOODSIG status field. This stands in contrast with check_signature()
that returns an error if more than one signature is encountered.
The lower degree of verification makes the use of verify_signed_buffer()
problematic if callers don't parse and validate the various parts of the
GPG status message themselves. And processing these messages seems like
a task that should be reserved to gpg-interface.c with the function
check_signature().
Furthermore, the use of verify_signed_buffer() makes it difficult to
introduce new functionality that relies on the content of the GPG status
lines.
Now all operations that does signature verification share a single entry
point to gpg-interface.c. This makes it easier to propagate changed or
additional functionality in GPG signature verification to all parts of
Git, without having odd edge-cases that don't perform the same degree of
verification.
[1] https://dev.gentoo.org/~mgorny/articles/attack-on-git-signature-verification.html
Signed-off-by: Hans Jerry Illikainen <hji@dyntopia.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The VALIDSIG status line from GnuPG with --status-fd is documented to
have 9 required and 1 optional fields [1]. The final, and optional,
field is used to specify the fingerprint of the primary key that made
the signature in case it was made by a subkey. However, this field is
only available for OpenPGP signatures; not for CMS/X.509.
If the VALIDSIG status line does not have the optional 10th field, the
current code will continue reading onto the next status line. And this
is the case for non-OpenPGP signatures [1].
The consequence is that a subsequent status line may be considered as
the "primary key" for signatures that does not have an actual primary
key.
Limit the search of these 9 or 10 fields to the single line to avoid
this problem. If the 10th field is missing, report that there is no
primary key fingerprint.
[Reference]
[1] GnuPG Details, General status codes
https://git.gnupg.org/cgi-bin/gitweb.cgi?p=gnupg.git;a=blob;f=doc/DETAILS;h=6ce340e8c04794add995e84308bb3091450bd28f;hb=HEAD#l483
The documentation says:
VALIDSIG <args>
The args are:
- <fingerprint_in_hex>
- <sig_creation_date>
- <sig-timestamp>
- <expire-timestamp>
- <sig-version>
- <reserved>
- <pubkey-algo>
- <hash-algo>
- <sig-class>
- [ <primary-key-fpr> ]
This status indicates that the signature is cryptographically
valid. [...] PRIMARY-KEY-FPR is the fingerprint of the primary key
or identical to the first argument.
The primary-key-fpr parameter is used for OpenPGP and not available
for CMS signatures. [...]
Signed-off-by: Hans Jerry Illikainen <hji@dyntopia.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Introduce a static replace_cstring() function to simplify repeated
pattern of free-and-xmemdupz() for GPG status line parsing.
This also helps us avoid potential memleaks if parsing of new status
lines are introduced in the future.
Signed-off-by: Hans Jerry Illikainen <hji@dyntopia.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
If the GPG output ends with trailing blank lines, after skipping
them over inside the loop to find the terminating NUL at the end,
the loop ends up looking for the next line, starting past the end.
Signed-off-by: Steven Roberts <sroberts@fenderq.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
New "--pretty=format:" placeholders %GF and %GP that show the GPG
key fingerprints have been invented.
* mg/gpg-fingerprint:
gpg-interface.c: obtain primary key fingerprint as well
gpg-interface.c: support getting key fingerprint via %GF format
gpg-interface.c: use flags to determine key/signer info presence
Detect and reject a signature block that has more than one GPG
signature.
* mg/gpg-parse-tighten:
gpg-interface.c: detect and reject multiple signatures on commits
Obtain the primary key fingerprint off VALIDSIG status message,
and expose it via %GP format.
Signed-off-by: Michał Górny <mgorny@gentoo.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Support processing VALIDSIG status that provides additional information
for valid signatures. Use this information to propagate signing key
fingerprint and expose it via %GF pretty format. This format can be
used to build safer key verification systems that verify the key via
complete fingerprint rather than short/long identifier provided by %GK.
Signed-off-by: Michał Górny <mgorny@gentoo.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Replace the logic used to determine whether key and signer information
is present to use explicit flags in sigcheck_gpg_status[] array. This
is more future-proof, since it makes it possible to add additional
statuses without having to explicitly update the conditions.
Signed-off-by: Michał Górny <mgorny@gentoo.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
GnuPG supports creating signatures consisting of multiple signature
packets. If such a signature is verified, it outputs all the status
messages for each signature separately. However, git currently does not
account for such scenario and gets terribly confused over getting
multiple *SIG statuses.
For example, if a malicious party alters a signed commit and appends
a new untrusted signature, git is going to ignore the original bad
signature and report untrusted commit instead. However, %GK and %GS
format strings may still expand to the data corresponding
to the original signature, potentially tricking the scripts into
trusting the malicious commit.
Given that the use of multiple signatures is quite rare, git does not
support creating them without jumping through a few hoops, and finally
supporting them properly would require extensive API improvement, it
seems reasonable to just reject them at the moment.
Signed-off-by: Michał Górny <mgorny@gentoo.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git verify-tag" and "git verify-commit" have been taught to use
the exit status of underlying "gpg --verify" to signal bad or
untrusted signature they found.
* jc/gpg-status:
gpg-interface: propagate exit status from gpg back to the callers
When gpg-interface API unified support for signature verification
codepaths for signed tags and signed commits in mid 2015 at around
v2.6.0-rc0~114, we accidentally loosened the GPG signature
verification.
Before that change, signed commits were verified by looking for
"G"ood signature from GPG, while ignoring the exit status of "gpg
--verify" process, while signed tags were verified by simply passing
the exit status of "gpg --verify" through. The unified code we
currently have ignores the exit status of "gpg --verify" and returns
successful verification when the signature matches an unexpired key
regardless of the trust placed on the key (i.e. in addition to "G"ood
ones, we accept "U"ntrusted ones).
Make these commands signal failure with their exit status when
underlying "gpg --verify" (or the custom command specified by
"gpg.program" configuration variable) does so. This essentially
changes their behaviour in a backward incompatible way to reject
signatures that have been made with untrusted keys even if they
correctly verify, as that is how "gpg --verify" behaves.
Note that the code still overrides a zero exit status obtained from
"gpg" (or gpg.program) if the output does not say the signature is
good or computes correctly but made with untrusted keys, to catch
a poorly written wrapper around "gpg" the user may give us.
We could exclude "U"ntrusted support from this fallback code, but
that would be making two backward incompatible changes in a single
commit, so let's avoid that for now. A follow-up change could do so
if desired.
Helped-by: Vojtech Myslivec <vojtech.myslivec@nic.cz>
Helped-by: brian m. carlson <sandals@crustytoothpaste.net>
Helped-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit allows git to create and check x509 type signatures using
gpgsm.
Signed-off-by: Henning Schild <henning.schild@siemens.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Supporting multiple signing formats we will have the need to configure a
custom program each. Add a new config value to cater for that.
Signed-off-by: Henning Schild <henning.schild@siemens.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
gnupg does print the keyid followed by a space and the signer comes
next. The same pattern is also used in gpgsm, but there the key length
would be 40 instead of 16. Instead of hardcoding the expected length,
find the first space and calculate it.
Input that does not match the expected format will be ignored now,
before we jumped to found+17 which might have been behind the end of an
unexpected string.
Signed-off-by: Henning Schild <henning.schild@siemens.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Create a struct that holds the format details for the supported formats.
At the moment that is still just "openpgp". This commit prepares for the
introduction of more formats, that might use other programs and match
other signatures.
Signed-off-by: Henning Schild <henning.schild@siemens.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add "gpg.format" where the user can specify which type of signature to
use for commits. At the moment only "openpgp" is supported and the value is
not even used. This commit prepares for a new types of signatures.
Signed-off-by: Henning Schild <henning.schild@siemens.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Turn parse_gpg_output into a static function, the only outside user was
migrated in an earlier commit.
Signed-off-by: Henning Schild <henning.schild@siemens.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A signed tag has a detached signature like this:
object ...
[...more header...]
This is the tag body.
-----BEGIN PGP SIGNATURE-----
[opaque gpg data]
-----END PGP SIGNATURE-----
Our parser finds the _first_ line that appears to start a
PGP signature block, meaning we may be confused by a
signature (or a signature-like line) in the actual body.
Let's keep parsing and always find the final block, which
should be the detached signature over all of the preceding
content.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Ben Toews <mastahyeti@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Let's separate the actual line-by-line parsing of signatures
from the notion of "is this a gpg signature line". That will
make it easier to do more refactoring of this loop in future
patches.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Ben Toews <mastahyeti@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We accidentally shed the "const" of our buffer by passing it
through memchr. Let's fix that, and while we're at it, move
our variable declaration inside the loop, which is the only
place that uses it.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Ben Toews <mastahyeti@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Even though our object sizes (from which these buffers would
come) are typically "unsigned long", this is something we'd
like to eventually fix (since it's only 32-bits even on
64-bit Windows). It makes more sense to use size_t when
taking an in-memory buffer.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Ben Toews <mastahyeti@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Let's drop "extern" from our declarations, which brings us
in line with our modern style guidelines. While we're
here, let's wrap some of the overly long lines, and move
docstrings for public functions to their declarations, since
they document the interface.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Ben Toews <mastahyeti@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The config handler for user.signingkey does not check for a
boolean value, and thus:
git -c user.signingkey tag
will segfault. We could fix this and even shorten the code
by using git_config_string(). But our set_signing_key()
helper is used by other code outside of gpg-interface.c, so
we must keep it (and we may as well use it, because unlike
git_config_string() it does not leak when we overwrite an
old value).
Ironically, the handler for gpg.program just below _could_
use git_config_string() but doesn't. But since we're going
to touch that in a future patch, we'll leave it alone for
now. We will add some whitespace and returns in preparation
for adding more config keys, though.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Ben Toews <mastahyeti@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The previous commit taught the tempfile code to give up
ownership over tempfiles that have been renamed or deleted.
That makes it possible to use a stack variable like this:
struct tempfile t;
create_tempfile(&t, ...);
...
if (!err)
rename_tempfile(&t, ...);
else
delete_tempfile(&t);
But doing it this way has a high potential for creating
memory errors. The tempfile we pass to create_tempfile()
ends up on a global linked list, and it's not safe for it to
go out of scope until we've called one of those two
deactivation functions.
Imagine that we add an early return from the function that
forgets to call delete_tempfile(). With a static or heap
tempfile variable, the worst case is that the tempfile hangs
around until the program exits (and some functions like
setup_shallow_temporary rely on this intentionally, creating
a tempfile and then leaving it for later cleanup).
But with a stack variable as above, this is a serious memory
error: the variable goes out of scope and may be filled with
garbage by the time the tempfile code looks at it. Let's
see if we can make it harder to get this wrong.
Since many callers need to allocate arbitrary numbers of
tempfiles, we can't rely on static storage as a general
solution. So we need to turn to the heap. We could just ask
all callers to pass us a heap variable, but that puts the
burden on them to call free() at the right time.
Instead, let's have the tempfile code handle the heap
allocation _and_ the deallocation (when the tempfile is
deactivated and removed from the list).
This changes the return value of all of the creation
functions. For the cleanup functions (delete and rename),
we'll add one extra bit of safety: instead of taking a
tempfile pointer, we'll take a pointer-to-pointer and set it
to NULL after freeing the object. This makes it safe to
double-call functions like delete_tempfile(), as the second
call treats the NULL input as a noop. Several callsites
follow this pattern.
The resulting patch does have a fair bit of noise, as each
caller needs to be converted to handle:
1. Storing a pointer instead of the struct itself.
2. Passing the pointer instead of taking the struct
address.
3. Handling a "struct tempfile *" return instead of a file
descriptor.
We could play games to make this less noisy. For example, by
defining the tempfile like this:
struct tempfile {
struct heap_allocated_part_of_tempfile {
int fd;
...etc
} *actual_data;
}
Callers would continue to have a "struct tempfile", and it
would be "active" only when the inner pointer was non-NULL.
But that just makes things more awkward in the long run.
There aren't that many callers, so we can simply bite
the bullet and adjust all of them. And the compiler makes it
easy for us to find them all.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When close_tempfile() fails, we delete the tempfile and
reset the fields of the tempfile struct. This makes it
easier for callers to return without cleaning up, but it
also makes this common pattern:
if (close_tempfile(tempfile))
return error_errno("error closing %s", tempfile->filename.buf);
wrong, because the "filename" field has been reset after the
failed close. And it's not easy to fix, as in many cases we
don't have another copy of the filename (e.g., if it was
created via one of the mks_tempfile functions, and we just
have the original template string).
Let's drop the feature that a failed close automatically
deletes the file. This puts the burden on the caller to do
the deletion themselves, but this isn't that big a deal.
Callers which do:
if (write(...) || close_tempfile(...)) {
delete_tempfile(...);
return -1;
}
already had to call delete when the write() failed, and so
aren't affected. Likewise, any caller which just calls die()
in the error path is OK; we'll delete the tempfile during
the atexit handler.
Because this patch changes the semantics of close_tempfile()
without changing its signature, all callers need to be
manually checked and converted to the new scheme. This patch
covers all in-tree callers, but there may be others for
not-yet-merged topics. To catch these, we rename the
function to close_tempfile_gently(), which will attract
compile-time attention to new callers. (Technically the
original could be considered "gentle" already in that it
didn't die() on errors, but this one is even more so).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
If close_tempfile() encounters an error, then it deletes the
tempfile and resets the "struct tempfile". But many code
paths ignore the return value and continue to use the
tempfile. Instead, we should generally treat this the same
as a write() error.
Note that in the postimage of some of these cases our error
message will be bogus after a failed close because we look
at tempfile->filename (either directly or via get_tempfile_path).
But after the failed close resets the tempfile object, this
is guaranteed to be the empty string. That will be addressed
in a future patch (because there are many more cases of the
same problem than just these instances).
Note also in the hunk in gpg-interface.c that it's fine to
call delete_tempfile() in the error path, even if
close_tempfile() failed and already deleted the file. The
tempfile code is smart enough to know the second deletion is
a noop.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We do a manual close() on the descriptor provided to us by
mks_tempfile. But this runs contrary to the advice in
tempfile.h, which notes that you should always use
close_tempfile(). Otherwise the descriptor may be reused
without the tempfile object knowing it, and the later call
to delete_tempfile() could close a random descriptor.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A common pattern to free a piece of memory and assign NULL to the
pointer that used to point at it has been replaced with a new
FREE_AND_NULL() macro.
* ab/free-and-null:
*.[ch] refactoring: make use of the FREE_AND_NULL() macro
coccinelle: make use of the "expression" FREE_AND_NULL() rule
coccinelle: add a rule to make "expression" code use FREE_AND_NULL()
coccinelle: make use of the "type" FREE_AND_NULL() rule
coccinelle: add a rule to make "type" code use FREE_AND_NULL()
git-compat-util: add a FREE_AND_NULL() wrapper around free(ptr); ptr = NULL
Replace occurrences of `free(ptr); ptr = NULL` which weren't caught by
the coccinelle rule. These fall into two categories:
- free/NULL assignments one after the other which coccinelle all put
on one line, which is functionally equivalent code, but very ugly.
- manually spotted occurrences where the NULL assignment isn't right
after the free() call.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Stop including config.h by default in cache.h. Instead only include
config.h in those files which require use of the config system.
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
According to gpg2's doc/DETAILS:
For each signature only one of the codes GOODSIG, BADSIG,
EXPSIG, EXPKEYSIG, REVKEYSIG or ERRSIG will be emitted.
gpg1 ("classic") behaves the same (although doc/DETAILS differs).
Currently, we parse gpg's status output for GOODSIG, BADSIG and
trust information and translate that into status codes G, B, U, N
for the %G? format specifier.
git-verify-* returns success in the GOODSIG case only. This is
somewhat in disagreement with gpg, which considers the first 5 of
the 6 above as VALIDSIG, but we err on the very safe side.
Introduce additional status codes E, X, Y, R for ERRSIG, EXPSIG,
EXPKEYSIG, and REVKEYSIG so that a user of %G? gets more information
about the absence of a 'G' on first glance.
Requested-by: Alex <agrambot@gmail.com>
Signed-off-by: Michael J Gruber <git@drmicha.warpmail.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Linus's original was rebased to apply to the maintenance track just
in case binary distributors that are stuck in the past want to take
it to their older codebase. Let's merge it up to more modern
codebase that has Peff's gpg-interface clean-up topic that appeared
after Git 2.9 was tagged.
* lt/gpg-show-long-key-in-signature-verification-maint:
gpg-interface: prefer "long" key format output when verifying pgp signatures
Yes, gpg2 already uses the long format by default, but most
distributions seem to still have "gpg" be the older 1.x version due to
compatibility reasons. And older versions of gpg only show the 32-bit
short ID, which is quite insecure.
This doesn't actually matter for the _verification_ itself: if the
verification passes, the pgp signature is good. But if you don't
actually have the key yet, and want to fetch it, or you want to check
exactly which key was used for verification and want to check it, we
should specify the key with more precision.
In fact, we should preferentially specify the whole key fingerprint, but
gpg doesn't actually support that. Which is really quite sad.
Showing the "long" format improves things to at least show 64 bits of
the fingerprint. That's a lot better, even if it's not perfect.
This change the log format for "git log --show-signature" from
commit 2376d31787
merged tag 'v2.9.3'
gpg: Signature made Fri 12 Aug 2016 09:17:59 AM PDT using RSA key ID 96AFE6CB
gpg: Good signature from "Junio C Hamano <gitster@pobox.com>"
gpg: aka "Junio C Hamano <jch@google.com>"
gpg: aka "Junio C Hamano <junio@pobox.com>"
Merge: 2807cd7b25e0c1ceafc5
Author: Junio C Hamano <gitster@pobox.com>
Date: Fri Aug 12 10:02:18 2016 -0700
to
commit 2376d31787
merged tag 'v2.9.3'
gpg: Signature made Fri 12 Aug 2016 09:17:59 AM PDT
gpg: using RSA key B0B5E88696AFE6CB
gpg: Good signature from "Junio C Hamano <gitster@pobox.com>"
gpg: aka "Junio C Hamano <jch@google.com>"
gpg: aka "Junio C Hamano <junio@pobox.com>"
Merge: 2807cd7b25e0c1ceafc5
Author: Junio C Hamano <gitster@pobox.com>
Date: Fri Aug 12 10:02:18 2016 -0700
(note the longer key ID, but also the reflowing of the text) and also
changes the format in the merge messages when merging a signed
tag.
If you already use gpg2 (either because it's installed by default, or
because you have set your gpg_program configuration to point to gpg2),
that already used the long format, you'll also see a change: it will now
have the same formatting as gpg 1.x, and the verification string looks
something like
gpg: Signature made Sun 24 Jul 2016 12:24:02 PM PDT
gpg: using RSA key 79BE3E4300411886
gpg: Good signature from "Linus Torvalds <torvalds@linux-foundation.org>" [ultimate]
where it used to be on one line:
gpg: Signature made Sun 24 Jul 2016 12:24:02 PM PDT using RSA key ID 79BE3E4300411886
gpg: Good signature from "Linus Torvalds <torvalds@linux-foundation.org>" [ultimate]
so there is certainly a chance this could break some automated scripting.
But the 32-bit key ID's really are broken. Also note that because of the
differences between gpg-1.x and gpg-2.x, hopefully any scripted key ID
parsing code (if such code exists) is already flexible enough to not care.
This was triggered by the fact that the "evil32" project keys ended up
leaking to the public key servers, so now there are 32-bit aliases for
just about every open source developer that you can easily get by
mistake if you use the 32-bit short ID format.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When we create a signature, it may happen that gpg returns with
"success" but not with an actual detached signature on stdout.
Check for the correct signature creation status to catch these cases
better. Really, --status-fd parsing is the only way to check gpg status
reliably. We do the same for verify already.
Signed-off-by: Michael J Gruber <git@drmicha.warpmail.net>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Similar to the prior commit for verify_signed_buffer, the
motivation here is both to make the code simpler, and to
avoid any possible deadlocks with gpg.
In this case we have the same "write to stdin, then read
from stdout" that the verify case had. This is unlikely to
be a problem in practice, since stdout has the detached
signature, which it cannot compute until it has read all of
stdin (if it were a non-detached signature, that would be a
problem, though).
We don't read from stderr at all currently. However, we will
want to in a future patch, so this also prepares us there
(and in that case gpg _does_ write before reading all of the
input, though again, it is unlikely that a key uid will fill
up a pipe buffer).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This is shorter and should make the function easier to
follow. But more importantly, it removes the possibility of
any deadlocks based on reading or writing to gpg.
It's not clear if such a deadlock is possible in practice.
We do write the whole payload before reading anything, so we
could deadlock there. However, in practice gpg will need to
read our whole input to verify the signature, so it will
drain our payload first. It could write an error to stderr
before reading, but it's unlikely that such an error
wouldn't be followed by it immediately exiting, or that the
error would actually be larger than a pipe buffer.
On the writing side, we drain stderr (with the
human-readable output) in its entirety before reading stdout
(with the status-fd data). Running strace on "gpg --verify"
does show interleaved output on the two descriptors:
write(2, "gpg: ", 5) = 5
write(2, "Signature made Thu 16 Jun 2016 0"..., 73) = 73
write(1, "[GNUPG:] SIG_ID tQw8KGcs9rBfLvAj"..., 66) = 66
write(1, "[GNUPG:] GOODSIG 69808639F9430ED"..., 60) = 60
write(2, "gpg: ", 5) = 5
write(2, "Good signature from \"Jeff King <"..., 47) = 47
write(2, "\n", 1) = 1
write(2, "gpg: ", 5) = 5
write(2, " aka \"Jeff King <"..., 49) = 49
write(2, "\n", 1) = 1
write(1, "[GNUPG:] VALIDSIG C49CE24156AF08"..., 135) = 135
write(1, "[GNUPG:] TRUST_ULTIMATE\n", 24) = 24
The second line written to stdout there contains the
signer's UID, which can be arbitrarily long. If it fills the
pipe buffer, then gpg would block writing to its stdout,
while we are blocked trying to read its stderr.
In practice, GPG seems to limit UIDs to 2048 bytes, so
unless your pipe buffer size is quite small, or unless gpg
does not enforce the limit under some conditions, this seems
unlikely in practice.
Still, it is not hard for us to be cautious and just use
pipe_command.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We use git_mkstemp to create a temporary file, and try to
clean it up in all exit paths from the function. But that
misses any cases where we die by signal, or by calling die()
in a sub-function. In addition, we missed one of the exit
paths.
Let's convert to using a tempfile object, which handles the
hard cases for us, and add the missing cleanup call. Note
that we would not simply want to rely on program exit to
catch our missed cleanup, as this function may be called
many times in a single program (for the same reason, we use
a static tempfile instead of heap-allocating a new one; that
gives an upper bound on our memory usage).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
If our caller gave us a non-NULL gpg_status parameter, we
write the gpg status into their strbuf. If they didn't, then
we write it to a temporary local strbuf (since we still need
to look at it). The variable "pbuf" adds an extra layer of
indirection so that the rest of the function can just access
whichever is appropriate.
However, the name "pbuf" isn't very descriptive, and it's
easy to get confused about what is supposed to be in it
(especially because we are reading both "status" and
"output" from gpg).
Rather than give it a more descriptive name, we can just use
gpg_status as our indirection pointer. Either it points to
the caller's input, or we can point it directly to our
temporary buffer.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Our argv allocations are relatively straightforward, but
this avoids us having to manually keep the count up to date
(or create new to-be-replaced slots in the declaration) when
we add new arguments.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The code for warning_errno/die_errno has been refactored and a new
error_errno() reporting helper is introduced.
* nd/error-errno: (41 commits)
wrapper.c: use warning_errno()
vcs-svn: use error_errno()
upload-pack.c: use error_errno()
unpack-trees.c: use error_errno()
transport-helper.c: use error_errno()
sha1_file.c: use {error,die,warning}_errno()
server-info.c: use error_errno()
sequencer.c: use error_errno()
run-command.c: use error_errno()
rerere.c: use error_errno() and warning_errno()
reachable.c: use error_errno()
mailmap.c: use error_errno()
ident.c: use warning_errno()
http.c: use error_errno() and warning_errno()
grep.c: use error_errno()
gpg-interface.c: use error_errno()
fast-import.c: use error_errno()
entry.c: use error_errno()
editor.c: use error_errno()
diff-no-index.c: use error_errno()
...
The verify_signed_buffer() function may trigger a SIGPIPE when the
GPG child process terminates early (due to a bad keyid, for example)
and Git tries to write to it afterwards. Previously, ignoring
SIGPIPE was done in builtin/verify-tag.c to avoid this issue.
However, any other caller who wants to call verify_signed_buffer()
would have to do the same.
Use sigchain_push(SIGPIPE, SIG_IGN) in verify_signed_buffer(),
pretty much like in sign_buffer(), so that any caller is not
required to perform this task.
This will avoid possible mistakes by further developers using
verify_signed_buffer().
Signed-off-by: Santiago Torres <santiago@nyu.edu>
Reviewed-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
verify-commit by default displays human-readable output on standard
error. However, it can also be useful to get access to the raw gpg
status information, which is machine-readable, allowing automated
implementation of signing policy. Add a --raw option to make
verify-commit produce the gpg status information on standard error
instead of the human-readable format.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The code to handle printing of signature data from a struct
signature_check is very similar between verify-commit and verify-tag.
Place this in a single function. verify-tag retains its special case
behavior of printing the tag even when no valid signature is found.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
verify-commit and verify-tag both share a central codepath for verifying
commits: check_signature. However, verify-tag exited successfully for
untrusted signature, while verify-commit exited unsuccessfully.
Centralize this signature check and make verify-commit adopt the older
verify-tag behavior. This behavior is more logical anyway, as the
signature is in fact valid, whether or not there's a path of trust to
the author.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
verify-tag was executing an entirely different codepath than
verify-commit, except for the underlying verify_signed_buffer. Move
much of the code from check_commit_signature to a generic
check_signature function and adjust both codepaths to call it.
Update verify-tag to explicitly output the signature text, as we now
call verify_signed_buffer with strbufs to catch the output, which
prevents it from being printed automatically.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Allow "git push" request to be signed, so that it can be verified and
audited, using the GPG signature of the person who pushed, that the
tips of branches at a public repository really point the commits
the pusher wanted to, without having to "trust" the server.
* jc/push-cert: (24 commits)
receive-pack::hmac_sha1(): copy the entire SHA-1 hash out
signed push: allow stale nonce in stateless mode
signed push: teach smart-HTTP to pass "git push --signed" around
signed push: fortify against replay attacks
signed push: add "pushee" header to push certificate
signed push: remove duplicated protocol info
send-pack: send feature request on push-cert packet
receive-pack: GPG-validate push certificates
push: the beginning of "git push --signed"
pack-protocol doc: typofix for PKT-LINE
gpg-interface: move parse_signature() to where it should be
gpg-interface: move parse_gpg_output() to where it should be
send-pack: clarify that cmds_sent is a boolean
send-pack: refactor inspecting and resetting status and sending commands
send-pack: rename "new_refs" to "need_pack_data"
receive-pack: factor out capability string generation
send-pack: factor out capability string generation
send-pack: always send capabilities
send-pack: refactor decision to send update per ref
send-pack: move REF_STATUS_REJECT_NODELETE logic a bit higher
...
Our signed-tag objects set the standard format used by Git to store
GPG-signed payload (i.e. the payload followed by its detached
signature) [*1*], and it made sense to have a helper to find the
boundary between the payload and its signature in tag.c back then.
Newer code added later to parse other kinds of objects that learned
to use the same format to store GPG-signed payload (e.g. signed
commits), however, kept using the helper from the same location.
Move it to gpg-interface; the helper is no longer about signed tag,
but it is how our code and data interact with GPG.
[Reference]
*1* http://thread.gmane.org/gmane.linux.kernel/297998/focus=1383
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Junio C Hamano
Hans Jerry Illikainen
Steven Roberts
Michał Górny
Henning Schild
Jeff King
Ævar Arnfjörð Bjarmason
Brandon Williams
Michael J Gruber
Linus Torvalds
Nguyễn Thái Ngọc Duy
Santiago Torres
brian m. carlson