The transition plan anticipates that we will allow signatures using
multiple algorithms in a single commit. In order to do so, we need to
use a different header per algorithm so that it will be obvious over
which data to compute the signature.
The transition plan specifies that we should use "gpgsig-sha256", so
wire up the commit code such that it can write and parse the current
algorithm, and it can remove the headers for any algorithm when creating
a new commit. Add tests to ensure that we write using the right header
and that git fsck doesn't reject these commits.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Previously, signature verification for merge and pull operations checked
if the key had a trust-level of either TRUST_NEVER or TRUST_UNDEFINED in
verify_merge_signature(). If that was the case, the process die()d.
The other code paths that did signature verification relied entirely on
the return code from check_commit_signature(). And signatures made with
a good key, irregardless of its trust level, was considered valid by
check_commit_signature().
This difference in behavior might induce users to erroneously assume
that the trust level of a key in their keyring is always considered by
Git, even for operations where it is not (e.g. during a verify-commit or
verify-tag).
The way it worked was by gpg-interface.c storing the result from the
key/signature status *and* the lowest-two trust levels in the `result`
member of the signature_check structure (the last of these status lines
that were encountered got written to `result`). These are documented in
GPG under the subsection `General status codes` and `Key related`,
respectively [1].
The GPG documentation says the following on the TRUST_ status codes [1]:
"""
These are several similar status codes:
- TRUST_UNDEFINED <error_token>
- TRUST_NEVER <error_token>
- TRUST_MARGINAL [0 [<validation_model>]]
- TRUST_FULLY [0 [<validation_model>]]
- TRUST_ULTIMATE [0 [<validation_model>]]
For good signatures one of these status lines are emitted to
indicate the validity of the key used to create the signature.
The error token values are currently only emitted by gpgsm.
"""
My interpretation is that the trust level is conceptionally different
from the validity of the key and/or signature. That seems to also have
been the assumption of the old code in check_signature() where a result
of 'G' (as in GOODSIG) and 'U' (as in TRUST_NEVER or TRUST_UNDEFINED)
were both considered a success.
The two cases where a result of 'U' had special meaning were in
verify_merge_signature() (where this caused git to die()) and in
format_commit_one() (where it affected the output of the %G? format
specifier).
I think it makes sense to refactor the processing of TRUST_ status lines
such that users can configure a minimum trust level that is enforced
globally, rather than have individual parts of git (e.g. merge) do it
themselves (except for a grace period with backward compatibility).
I also think it makes sense to not store the trust level in the same
struct member as the key/signature status. While the presence of a
TRUST_ status code does imply that the signature is good (see the first
paragraph in the included snippet above), as far as I can tell, the
order of the status lines from GPG isn't well-defined; thus it would
seem plausible that the trust level could be overwritten with the
key/signature status if they were stored in the same member of the
signature_check structure.
This patch introduces a new configuration option: gpg.minTrustLevel. It
consolidates trust-level verification to gpg-interface.c and adds a new
`trust_level` member to the signature_check structure.
Backward-compatibility is maintained by introducing a special case in
verify_merge_signature() such that if no user-configurable
gpg.minTrustLevel is set, then the old behavior of rejecting
TRUST_UNDEFINED and TRUST_NEVER is enforced. If, on the other hand,
gpg.minTrustLevel is set, then that value overrides the old behavior.
Similarly, the %G? format specifier will continue show 'U' for
signatures made with a key that has a trust level of TRUST_UNDEFINED or
TRUST_NEVER, even though the 'U' character no longer exist in the
`result` member of the signature_check structure. A new format
specifier, %GT, is also introduced for users that want to show all
possible trust levels for a signature.
Another approach would have been to simply drop the trust-level
requirement in verify_merge_signature(). This would also have made the
behavior consistent with other parts of git that perform signature
verification. However, requiring a minimum trust level for signing keys
does seem to have a real-world use-case. For example, the build system
used by the Qubes OS project currently parses the raw output from
verify-tag in order to assert a minimum trust level for keys used to
sign git tags [2].
[1] https://git.gnupg.org/cgi-bin/gitweb.cgi?p=gnupg.git;a=blob;f=doc/doc/DETAILS;h=bd00006e933ac56719b1edd2478ecd79273eae72;hb=refs/heads/master
[2] 9674c1991d/scripts/verify-git-tag (L43)
Signed-off-by: Hans Jerry Illikainen <hji@dyntopia.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add --gpg-sign option in commit-tree, which was documented, but not
implemented, in 55ca3f99ae. Add tests for the --gpg-sign option.
Signed-off-by: Brandon Richardson <brandon1024.br@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
If `git commit-tree HEAD^{tree}` fails on us and produces no output on
stdout, we will substitute that empty string and execute `git tag
ninth-unsigned`, i.e., we will tag HEAD rather than a newly created
object. But we are lucky: we have a signature on HEAD, so we should
eventually fail the next test, where we verify that "ninth-unsigned" is
indeed unsigned.
We have a similar problem a few lines later. If `git commit-tree -S`
fails with no output, we will happily tag HEAD as "tenth-signed". Here,
we are not so lucky. The tag ends up on the same commit as
"eighth-signed-alt", and that's a signed commit, so t7510-signed-commit
will pass, despite `git commit-tree -S` failing.
Make these `git commit-tree` invocations a direct part of the &&-chain,
so that we can rely less on luck and set a better example for future
tests modeled after this one. Fix a 9/10 copy/paste error while at it.
Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Signed-off-by: Brandon Richardson <brandon1024.br@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add a dedicated signing subkey to the key identified as 'Eris
Discordia', and update tests appropriately. GnuPG will now sign commits
using the dedicated signing subkey, changing the value of %GK and %GF,
and effectively creating a test case for %GF!=%GP.
Signed-off-by: Michał Górny <mgorny@gentoo.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Test %GP in addition to %GF in custom format checks. With current
keyring, both have the same value.
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>
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>
Test setting gpg.format to both invalid and valid values.
Signed-off-by: Henning Schild <henning.schild@siemens.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A couple of test scripts create forged GPG signed commits or tags to
check that such forgery can't fool various git commands' signature
verification. All but one of those test scripts are prone to
occasional failures because the forgery creates a bogus GPG signature,
and git commands error out with an unexpected error message, e.g.
"Commit deadbeef does not have a GPG signature" instead of "... has a
bad GPG signature".
't5573-pull-verify-signatures.sh', 't7510-signed-commit.sh' and
't7612-merge-verify-signatures.sh' create forged signed commits like
this:
git commit -S -m "bad on side" &&
git cat-file commit side-bad >raw &&
sed -e "s/bad/forged bad/" raw >forged &&
git hash-object -w -t commit forged >forged.commit
On rare occasions the given pattern occurs not only in the commit
message but in the GPG signature as well, and after it's replaced in
the signature the resulting signature becomes invalid, GPG will report
CRC error and that it couldn't find any signature, which will then
ultimately cause the test failure.
Since in all three cases the pattern to be replaced during the forgery
is the first word of the commit message's subject line, and since the
GPG signature in the commit object is indented by a space, let's just
anchor those patterns to the beginning of the line to prevent this
issue.
The test script 't7030-verify-tag.sh' creates a forged signed tag
object in a similar way by replacing the pattern "seventh", but the
GPG signature in tag objects is not indented by a space, so the above
solution is not applicable in this case. However, in the tag object
in question the pattern "seventh" occurs not only in the tag message
but in the 'tag' header as well. To create a forged tag object it's
sufficient to replace only one of the two occurences, so modify the
sed script to limit the pattern to the 'tag' header (i.e. a line
beginning with "tag ", which, because of the space character, can
never occur in the base64-encoded GPG signature).
Note that the forgery in 't7004-tag.sh' is not affected by this issue:
while 't7004' does create a forged signed tag kind of the same way,
it replaces "signed-tag" in the tag object, which, because of the '-'
character, can never occur in the base64-encoded GPG signarute.
Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The two tests 'detect fudged signature' and 'detect fudged signature
with NUL' in 't7510-signed-commit.sh' check that 'git verify-commit'
errors out when encountering a forged commit, but they do so by
running
! git verify-commit ...
Use 'test_must_fail' instead, because that would catch potential
unexpected errors like a segfault as well.
Signed-off-by: SZEDER Gábor <szeder.dev@gmail.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>
Users may want to always use "--show-signature" while using git-log and
related commands.
When log.showSignature is set to true, git-log and related commands will
behave as if "--show-signature" was given to them.
Note that this config variable is meant to affect git-log, git-show,
git-whatchanged and git-reflog. Other commands like git-format-patch,
git-rev-list are not to be affected by this config variable.
Signed-off-by: Mehul Jain <mehul.jain2029@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git commit-tree" plumbing command required the user to always sign
its result when the user sets the commit.gpgsign configuration
variable, which was an ancient mistake. Rework "git rebase" that
relied on this mistake so that it reads commit.gpgsign and pass (or
not pass) the -S option to "git commit-tree" to keep the end-user
expectation the same, while teaching "git commit-tree" to ignore
the configuration variable. This will stop requiring the users to
sign commit objects used internally as an implementation detail of
"git stash".
* jc/commit-tree-ignore-commit-gpgsign:
commit-tree: do not pay attention to commit.gpgsign
ba3c69a9 (commit: teach --gpg-sign option, 2011-10-05) introduced a
"signed commit" by teaching the --[no]-gpg-sign option and the
commit.gpgsign configuration variable to various commands that
create commits.
Teaching these to "git commit" and "git merge", both of which are
end-user facing Porcelain commands, was perfectly fine. Allowing
the plumbing "git commit-tree" to suddenly change the behaviour to
surprise the scripts by paying attention to commit.gpgsign was not.
Among the in-tree scripts, filter-branch, quiltimport, rebase and
stash are the commands that run "commit-tree". If any of these
wants to allow users to always sign every single commit, they should
offer their own configuration (e.g. "filterBranch.gpgsign") with an
option to disable signing (e.g. "git filter-branch --no-gpgsign").
Ignoring commit.gpgsign option _obviously_ breaks the backward
compatibility, but it is easy to follow the standard pattern in
scripts to honor whatever configuration variable they choose to
follow. E.g.
case $(git config --bool commit.gpgsign) in
true) sign=-S ;;
*) sign= ;;
esac &&
git commit-tree $sign ...whatever other args...
Do so to make sure that "git rebase" keeps paying attention to the
configuration variable, which unfortunately is a documented mistake.
Helped-by: Jeff King <peff@peff.net>
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>
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 exits successfully if the signature is good but the key is
untrusted. verify-commit exits unsuccessfully. This divergence in
behavior is unexpected and unwanted. Since verify-tag existed earlier,
add a failing test to have verify-commit share verify-tag's behavior.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
People often forget to chain the commands in their test together
with &&, leaving a failure from an earlier command in the test go
unnoticed. The new GIT_TEST_CHAIN_LINT mechanism allows you to
catch such a mistake more easily.
* jk/test-chain-lint: (36 commits)
t9001: drop save_confirm helper
t0020: use test_* helpers instead of hand-rolled messages
t: simplify loop exit-code status variables
t: fix some trivial cases of ignored exit codes in loops
t7701: fix ignored exit code inside loop
t3305: fix ignored exit code inside loop
t0020: fix ignored exit code inside loops
perf-lib: fix ignored exit code inside loop
t6039: fix broken && chain
t9158, t9161: fix broken &&-chain in git-svn tests
t9104: fix test for following larger parents
t4104: drop hand-rolled error reporting
t0005: fix broken &&-chains
t7004: fix embedded single-quotes
t0050: appease --chain-lint
t9001: use test_when_finished
t4117: use modern test_* helpers
t6034: use modern test_* helpers
t1301: use modern test_* helpers
t0020: use modern test_* helpers
...
Workarounds for certain build of GPG that triggered false breakage
in a test.
* mg/verify-commit:
t7510: do not fail when gpg warns about insecure memory
These are tests which are missing a link in their &&-chain,
but during a setup phase. We may fail to notice failure in
commands that build the test environment, but these are
typically not expected to fail at all (but it's still good
to double-check that our test environment is what we
expect).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Depending on how gpg was built, it may issue the following
message to stderr when run:
Warning: using insecure memory!
When the test is collecting gpg output it is therefore not
enough to just match on a "gpg: " prefix it must also match
on a "Warning: " prefix wherever it needs to match lines
that have been produced by gpg.
Signed-off-by: Kyle J. McKay <mackyle@gmail.com>
Acked-by: Michael J Gruber <git@drmicha.warpmail.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add 'verify-commit' to be used in a way similar to 'verify-tag' is
used. Further work on verifying the mergetags might be needed.
* mg/verify-commit:
t7510: test verify-commit
t7510: exit for loop with test result
verify-commit: scriptable commit signature verification
gpg-interface: provide access to the payload
gpg-interface: provide clear helper for struct signature_check
The final test in t7510 checks that "--format" placeholders
that look similar to GPG placeholders (but that we don't
actually understand) are passed through. That test was
placed in t7510, since the other GPG placeholder tests are
there. However, it does not have a GPG prerequisite, because
it is not actually checking any signed commits.
This causes the test to erroneously fail when gpg is not
installed on a system, however. Not because we need signed
commits, but because we need _any_ commit to run "git log".
If we don't have gpg installed, t7510 doesn't create any
commits at all.
We can fix this by moving the test into t6006. This is
arguably a better place anyway, because it is where we test
most of the other placeholders (we do not test GPG
placeholders there because of the infrastructure needed to
make signed commits).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This mixes the "git verify-commit" tests in with the "git show
--show-signature" tests, to keep the tests more readable.
The tests already mix in the "call show" tests with the "verify" tests.
So in case of a test beakage, a '-v' run would be needed to reveal the
exact point of breakage anyway.
Additionally, test the actual output of "git verify-commit" and "git
show --show-signature" and compare to "git cat-file".
Signed-off-by: Michael J Gruber <git@drmicha.warpmail.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
t7510 uses for loops in a subshell, which need to make sure that the test
returns with the appropriate error code from within the loop.
Restructure the loops as the usual && chains with a single point of
"exit 1" at the end of the loop to make this clearer.
Signed-off-by: Michael J Gruber <git@drmicha.warpmail.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
If the user asks for --format=%G with nothing else, we
correctly realize that "%G" is not a valid placeholder (it
should be "%G?", "%GK", etc). But we still tell the
strbuf_expand code that we consumed 2 characters, causing it
to jump over the trailing NUL and output garbage.
This also fixes the case where "%GX" would be consumed (and
produce no output). In other cases, we pass unrecognized
placeholders through to the final string.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We do not check these along with the other pretty-format
placeholders in t6006, because we need signed commits to
make them interesting. t7510 has such commits, and can
easily exercise them in addition to the regular
--show-signature code path.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We tested both good and bad signatures, but not ones made
correctly but with a key for which we have no trust.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We check multiple commits in a loop. Because we want to
break out of the loop if any single iteration fails, we use
a subshell/exit like:
(
for i in $stuff
do
do-something $i || exit 1
done
)
However, we are inconsistent in our loop body. Some commands
get their own "|| exit 1", and others try to chain to the
next command with "&&", like:
X &&
Y || exit 1
Z || exit 1
This is a little hard to read and follow, because X and Y
are treated differently for no good reason. But much worse,
the second loop follows a similar pattern and gets it wrong.
"Y" is expected to fail, so we use "&& exit 1", giving us:
X &&
Y && exit 1
Z || exit 1
That gets the test for X wrong (we do not exit unless both X
fails and Y unexpectedly succeeds, but we would want to exit
if _either_ is wrong). We can write this clearly and
correctly by consistently using "&&", followed by a single
"|| exit 1", and negating Y with "!" (as we would in a
normal &&-chain). Like:
X &&
! Y &&
Z || exit 1
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Our setup creates a sequence of commits, each with its own
tag. However, we sometimes refer to "seventh-signed" as
"master". This works, since it is at the tip of the created
branch, but is brittle if new tests need to add more
commits. Let's use its tag name to be unambiguous.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The tests are checking that :
- when commit.gpgsign is true, "git commit" creates signed commits
- when commit.gpgsign is false, "git commit" creates unsigned commits
- when commit.gpgsign is true, "git commit --no-gpg-sign" creates
unsigned commits
- when commit.gpgsign is true, "git rebase -f" creates signed commits
Signed-off-by: Nicolas Vigier <boklm@mars-attacks.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Any existing commit signature was made against the contents of the old
commit, including its committer date that is about to change, and will
become invalid by amending it.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
