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git/t/t7510-signed-commit.sh
Jeff King 7891e46585 gpg-interface: set trust level of missing key to "undefined"
In check_signature(), we initialize the trust_level field to "-1", with
the idea that if gpg does not return a trust level at all (if there is
no signature, or if the signature is made by an unknown key), we'll
use that value. But this has two problems:

  1. Since the field is an enum, it's up to the compiler to decide what
     underlying storage to use, and it only has to fit the values we've
     declared. So we may not be able to store "-1" at all. And indeed,
     on my system (linux with gcc), the resulting enum is an unsigned
     32-bit value, and -1 becomes 4294967295.

     The difference may seem academic (and you even get "-1" if you pass
     it to printf("%d")), but it means that code like this:

       status |= sigc->trust_level < configured_min_trust_level;

     does not necessarily behave as expected. This turns out not to be a
     bug in practice, though, because we keep the "-1" only when gpg did
     not report a signature from a known key, in which case the line
     above:

       status |= sigc->result != 'G';

     would always set status to non-zero anyway. So only a 'G' signature
     with no parsed trust level would cause a problem, which doesn't
     seem likely to trigger (outside of unexpected gpg behavior).

  2. When using the "%GT" format placeholder, we pass the value to
     gpg_trust_level_to_str(), which complains that the value is out of
     range with a BUG(). This behavior was introduced by 803978da49
     (gpg-interface: add function for converting trust level to string,
     2022-07-11). Before that, we just did a switch() on the enum, and
     anything that wasn't matched would end up as the empty string.

     Curiously, solving this by naively doing:

       if (level < 0)
               return "";

     in that function isn't sufficient. Because of (1) above, the
     compiler can (and does in my case) actually remove that conditional
     as dead code!

We can solve both by representing this state as an enum value. We could
do this by adding a new "unknown" value. But this really seems to match
the existing "undefined" level well. GPG describes this as "Not enough
information for calculation".

We have tests in t7510 that trigger this case (verifying a signature
from a key that we don't have, and then checking various %G
placeholders), but they didn't notice the BUG() because we didn't look
at %GT for that case! Let's make sure we check all %G placeholders for
each case in the formatting tests.

The interesting ones here are "show unknown signature with custom
format" and "show lack of signature with custom format", both of which
would BUG() before, and now turn %GT into "undefined". Prior to
803978da49 they would have turned it into the empty string, but I think
saying "undefined" consistently is a reasonable outcome, and probably
makes life easier for anyone parsing the output (and any such parser had
to be ready to see "undefined" already).

The other modified tests produce the same output before and after this
patch, but now we're consistently checking both %G? and %GT in all of
them.

Signed-off-by: Jeff King <peff@peff.net>
Reported-by: Rolf Eike Beer <eb@emlix.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-04-19 08:30:54 -07:00

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#!/bin/sh
test_description='signed commit tests'
GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
. ./test-lib.sh
GNUPGHOME_NOT_USED=$GNUPGHOME
. "$TEST_DIRECTORY/lib-gpg.sh"
test_expect_success GPG 'create signed commits' '
test_oid_cache <<-\EOF &&
header sha1:gpgsig
header sha256:gpgsig-sha256
EOF
test_when_finished "test_unconfig commit.gpgsign" &&
echo 1 >file && git add file &&
test_tick && git commit -S -m initial &&
git tag initial &&
git branch side &&
echo 2 >file && test_tick && git commit -a -S -m second &&
git tag second &&
git checkout side &&
echo 3 >elif && git add elif &&
test_tick && git commit -m "third on side" &&
git checkout main &&
test_tick && git merge -S side &&
git tag merge &&
echo 4 >file && test_tick && git commit -a -m "fourth unsigned" &&
git tag fourth-unsigned &&
test_tick && git commit --amend -S -m "fourth signed" &&
git tag fourth-signed &&
git config commit.gpgsign true &&
echo 5 >file && test_tick && git commit -a -m "fifth signed" &&
git tag fifth-signed &&
git config commit.gpgsign false &&
echo 6 >file && test_tick && git commit -a -m "sixth" &&
git tag sixth-unsigned &&
git config commit.gpgsign true &&
echo 7 >file && test_tick && git commit -a -m "seventh" --no-gpg-sign &&
git tag seventh-unsigned &&
test_tick && git rebase -f HEAD^^ && git tag sixth-signed HEAD^ &&
git tag seventh-signed &&
echo 8 >file && test_tick && git commit -a -m eighth -SB7227189 &&
git tag eighth-signed-alt &&
# commit.gpgsign is still on but this must not be signed
echo 9 | git commit-tree HEAD^{tree} >oid &&
test_line_count = 1 oid &&
git tag ninth-unsigned $(cat oid) &&
# explicit -S of course must sign.
echo 10 | git commit-tree -S HEAD^{tree} >oid &&
test_line_count = 1 oid &&
git tag tenth-signed $(cat oid) &&
# --gpg-sign[=<key-id>] must sign.
echo 11 | git commit-tree --gpg-sign HEAD^{tree} >oid &&
test_line_count = 1 oid &&
git tag eleventh-signed $(cat oid) &&
echo 12 | git commit-tree --gpg-sign=B7227189 HEAD^{tree} >oid &&
test_line_count = 1 oid &&
git tag twelfth-signed-alt $(cat oid)
'
test_expect_success GPG 'verify and show signatures' '
(
for commit in initial second merge fourth-signed \
fifth-signed sixth-signed seventh-signed tenth-signed \
eleventh-signed
do
git verify-commit $commit &&
git show --pretty=short --show-signature $commit >actual &&
grep "Good signature from" actual &&
! grep "BAD signature from" actual &&
echo $commit OK || exit 1
done
) &&
(
for commit in merge^2 fourth-unsigned sixth-unsigned \
seventh-unsigned ninth-unsigned
do
test_must_fail git verify-commit $commit &&
git show --pretty=short --show-signature $commit >actual &&
! grep "Good signature from" actual &&
! grep "BAD signature from" actual &&
echo $commit OK || exit 1
done
) &&
(
for commit in eighth-signed-alt twelfth-signed-alt
do
git show --pretty=short --show-signature $commit >actual &&
grep "Good signature from" actual &&
! grep "BAD signature from" actual &&
grep "not certified" actual &&
echo $commit OK || exit 1
done
)
'
test_expect_success GPG 'verify-commit exits failure on unknown signature' '
test_must_fail env GNUPGHOME="$GNUPGHOME_NOT_USED" git verify-commit initial 2>actual &&
! grep "Good signature from" actual &&
! grep "BAD signature from" actual &&
grep -q -F -e "No public key" -e "public key not found" actual
'
test_expect_success GPG 'verify-commit exits success on untrusted signature' '
git verify-commit eighth-signed-alt 2>actual &&
grep "Good signature from" actual &&
! grep "BAD signature from" actual &&
grep "not certified" actual
'
test_expect_success GPG 'verify-commit exits success with matching minTrustLevel' '
test_config gpg.minTrustLevel ultimate &&
git verify-commit sixth-signed
'
test_expect_success GPG 'verify-commit exits success with low minTrustLevel' '
test_config gpg.minTrustLevel fully &&
git verify-commit sixth-signed
'
test_expect_success GPG 'verify-commit exits failure with high minTrustLevel' '
test_config gpg.minTrustLevel ultimate &&
test_must_fail git verify-commit eighth-signed-alt
'
test_expect_success GPG 'verify signatures with --raw' '
(
for commit in initial second merge fourth-signed fifth-signed sixth-signed seventh-signed
do
git verify-commit --raw $commit 2>actual &&
grep "GOODSIG" actual &&
! grep "BADSIG" actual &&
echo $commit OK || exit 1
done
) &&
(
for commit in merge^2 fourth-unsigned sixth-unsigned seventh-unsigned
do
test_must_fail git verify-commit --raw $commit 2>actual &&
! grep "GOODSIG" actual &&
! grep "BADSIG" actual &&
echo $commit OK || exit 1
done
) &&
(
for commit in eighth-signed-alt
do
git verify-commit --raw $commit 2>actual &&
grep "GOODSIG" actual &&
! grep "BADSIG" actual &&
grep "TRUST_UNDEFINED" actual &&
echo $commit OK || exit 1
done
)
'
test_expect_success GPG 'proper header is used for hash algorithm' '
git cat-file commit fourth-signed >output &&
grep "^$(test_oid header) -----BEGIN PGP SIGNATURE-----" output
'
test_expect_success GPG 'show signed commit with signature' '
git show -s initial >commit &&
git show -s --show-signature initial >show &&
git verify-commit -v initial >verify.1 2>verify.2 &&
git cat-file commit initial >cat &&
grep -v -e "gpg: " -e "Warning: " show >show.commit &&
grep -e "gpg: " -e "Warning: " show >show.gpg &&
grep -v "^ " cat | grep -v "^gpgsig.* " >cat.commit &&
test_cmp show.commit commit &&
test_cmp show.gpg verify.2 &&
test_cmp cat.commit verify.1
'
test_expect_success GPG 'detect fudged signature' '
git cat-file commit seventh-signed >raw &&
sed -e "s/^seventh/7th forged/" raw >forged1 &&
git hash-object -w -t commit forged1 >forged1.commit &&
test_must_fail git verify-commit $(cat forged1.commit) &&
git show --pretty=short --show-signature $(cat forged1.commit) >actual1 &&
grep "BAD signature from" actual1 &&
! grep "Good signature from" actual1
'
test_expect_success GPG 'detect fudged signature with NUL' '
git cat-file commit seventh-signed >raw &&
cat raw >forged2 &&
echo Qwik | tr "Q" "\000" >>forged2 &&
git hash-object --literally -w -t commit forged2 >forged2.commit &&
test_must_fail git verify-commit $(cat forged2.commit) &&
git show --pretty=short --show-signature $(cat forged2.commit) >actual2 &&
grep "BAD signature from" actual2 &&
! grep "Good signature from" actual2
'
test_expect_success GPG 'amending already signed commit' '
git checkout -f fourth-signed^0 &&
git commit --amend -S --no-edit &&
git verify-commit HEAD &&
git show -s --show-signature HEAD >actual &&
grep "Good signature from" actual &&
! grep "BAD signature from" actual
'
test_expect_success GPG 'show good signature with custom format' '
cat >expect <<-\EOF &&
G
ultimate
13B6F51ECDDE430D
C O Mitter <committer@example.com>
73D758744BE721698EC54E8713B6F51ECDDE430D
73D758744BE721698EC54E8713B6F51ECDDE430D
EOF
git log -1 --format="%G?%n%GT%n%GK%n%GS%n%GF%n%GP" sixth-signed >actual &&
test_cmp expect actual
'
test_expect_success GPG 'show bad signature with custom format' '
cat >expect <<-\EOF &&
B
undefined
13B6F51ECDDE430D
C O Mitter <committer@example.com>
EOF
git log -1 --format="%G?%n%GT%n%GK%n%GS%n%GF%n%GP" $(cat forged1.commit) >actual &&
test_cmp expect actual
'
test_expect_success GPG 'show untrusted signature with custom format' '
cat >expect <<-\EOF &&
U
undefined
65A0EEA02E30CAD7
Eris Discordia <discord@example.net>
F8364A59E07FFE9F4D63005A65A0EEA02E30CAD7
D4BE22311AD3131E5EDA29A461092E85B7227189
EOF
git log -1 --format="%G?%n%GT%n%GK%n%GS%n%GF%n%GP" eighth-signed-alt >actual &&
test_cmp expect actual
'
test_expect_success GPG 'show untrusted signature with undefined trust level' '
cat >expect <<-\EOF &&
U
undefined
65A0EEA02E30CAD7
Eris Discordia <discord@example.net>
F8364A59E07FFE9F4D63005A65A0EEA02E30CAD7
D4BE22311AD3131E5EDA29A461092E85B7227189
EOF
git log -1 --format="%G?%n%GT%n%GK%n%GS%n%GF%n%GP" eighth-signed-alt >actual &&
test_cmp expect actual
'
test_expect_success GPG 'show untrusted signature with ultimate trust level' '
cat >expect <<-\EOF &&
G
ultimate
13B6F51ECDDE430D
C O Mitter <committer@example.com>
73D758744BE721698EC54E8713B6F51ECDDE430D
73D758744BE721698EC54E8713B6F51ECDDE430D
EOF
git log -1 --format="%G?%n%GT%n%GK%n%GS%n%GF%n%GP" sixth-signed >actual &&
test_cmp expect actual
'
test_expect_success GPG 'show unknown signature with custom format' '
cat >expect <<-\EOF &&
E
undefined
65A0EEA02E30CAD7
EOF
GNUPGHOME="$GNUPGHOME_NOT_USED" git log -1 --format="%G?%n%GT%n%GK%n%GS%n%GF%n%GP" eighth-signed-alt >actual &&
test_cmp expect actual
'
test_expect_success GPG 'show lack of signature with custom format' '
cat >expect <<-\EOF &&
N
undefined
EOF
git log -1 --format="%G?%n%GT%n%GK%n%GS%n%GF%n%GP" seventh-unsigned >actual &&
test_cmp expect actual
'
test_expect_success GPG 'log.showsignature behaves like --show-signature' '
test_config log.showsignature true &&
git show initial >actual &&
grep "gpg: Signature made" actual &&
grep "gpg: Good signature" actual
'
test_expect_success GPG 'check config gpg.format values' '
test_config gpg.format openpgp &&
git commit -S --amend -m "success" &&
test_config gpg.format OpEnPgP &&
test_must_fail git commit -S --amend -m "fail"
'
test_expect_success GPG 'detect fudged commit with double signature' '
sed -e "/gpgsig/,/END PGP/d" forged1 >double-base &&
sed -n -e "/gpgsig/,/END PGP/p" forged1 | \
sed -e "s/^$(test_oid header)//;s/^ //" | gpg --dearmor >double-sig1.sig &&
gpg -o double-sig2.sig -u 29472784 --detach-sign double-base &&
cat double-sig1.sig double-sig2.sig | gpg --enarmor >double-combined.asc &&
sed -e "s/^\(-.*\)ARMORED FILE/\1SIGNATURE/;1s/^/$(test_oid header) /;2,\$s/^/ /" \
double-combined.asc > double-gpgsig &&
sed -e "/committer/r double-gpgsig" double-base >double-commit &&
git hash-object -w -t commit double-commit >double-commit.commit &&
test_must_fail git verify-commit $(cat double-commit.commit) &&
git show --pretty=short --show-signature $(cat double-commit.commit) >double-actual &&
grep "BAD signature from" double-actual &&
grep "Good signature from" double-actual
'
test_expect_success GPG 'show double signature with custom format' '
cat >expect <<-\EOF &&
E
EOF
git log -1 --format="%G?%n%GK%n%GS%n%GF%n%GP" $(cat double-commit.commit) >actual &&
test_cmp expect actual
'
# NEEDSWORK: This test relies on the test_tick commit/author dates from the first
# 'create signed commits' test even though it creates its own
test_expect_success GPG 'verify-commit verifies multiply signed commits' '
git init multiply-signed &&
cd multiply-signed &&
test_commit first &&
echo 1 >second &&
git add second &&
tree=$(git write-tree) &&
parent=$(git rev-parse HEAD^{commit}) &&
git commit --gpg-sign -m second &&
git cat-file commit HEAD &&
# Avoid trailing whitespace.
sed -e "s/^Q//" -e "s/^Z/ /" >commit <<-EOF &&
Qtree $tree
Qparent $parent
Qauthor A U Thor <author@example.com> 1112912653 -0700
Qcommitter C O Mitter <committer@example.com> 1112912653 -0700
Qgpgsig -----BEGIN PGP SIGNATURE-----
QZ
Q iHQEABECADQWIQRz11h0S+chaY7FTocTtvUezd5DDQUCX/uBDRYcY29tbWl0dGVy
Q QGV4YW1wbGUuY29tAAoJEBO29R7N3kMNd+8AoK1I8mhLHviPH+q2I5fIVgPsEtYC
Q AKCTqBh+VabJceXcGIZuF0Ry+udbBQ==
Q =tQ0N
Q -----END PGP SIGNATURE-----
Qgpgsig-sha256 -----BEGIN PGP SIGNATURE-----
QZ
Q iHQEABECADQWIQRz11h0S+chaY7FTocTtvUezd5DDQUCX/uBIBYcY29tbWl0dGVy
Q QGV4YW1wbGUuY29tAAoJEBO29R7N3kMN/NEAn0XO9RYSBj2dFyozi0JKSbssYMtO
Q AJwKCQ1BQOtuwz//IjU8TiS+6S4iUw==
Q =pIwP
Q -----END PGP SIGNATURE-----
Q
Qsecond
EOF
head=$(git hash-object -t commit -w commit) &&
git reset --hard $head &&
git verify-commit $head 2>actual &&
grep "Good signature from" actual &&
! grep "BAD signature from" actual
'
test_expect_success 'custom `gpg.program`' '
write_script fake-gpg <<-\EOF &&
args="$*"
# skip uninteresting options
while case "$1" in
--status-fd=*|--keyid-format=*) ;; # skip
*) break;;
esac; do shift; done
case "$1" in
-bsau)
test -z "$LET_GPG_PROGRAM_FAIL" || {
echo "zOMG signing failed!" >&2
exit 1
}
cat >sign.file
echo "[GNUPG:] SIG_CREATED $args" >&2
echo "-----BEGIN PGP MESSAGE-----"
echo "$args"
echo "-----END PGP MESSAGE-----"
;;
--verify)
cat "$2" >verify.file
exit 0
;;
*)
echo "Unhandled args: $*" >&2
exit 1
;;
esac
EOF
test_config gpg.program "$(pwd)/fake-gpg" &&
git commit -S --allow-empty -m signed-commit &&
test_path_exists sign.file &&
git show --show-signature &&
test_path_exists verify.file &&
test_must_fail env LET_GPG_PROGRAM_FAIL=1 \
git commit -S --allow-empty -m must-fail 2>err &&
grep zOMG err
'
test_done