git/t/t7030-verify-tag.sh
SZEDER Gábor 2f3cbcd8c5 tests: make forging GPG signed commits and tags more robust
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>
2018-06-11 10:19:03 -07:00

143 lines
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Executable File

#!/bin/sh
test_description='signed tag tests'
. ./test-lib.sh
. "$TEST_DIRECTORY/lib-gpg.sh"
test_expect_success GPG 'create signed tags' '
echo 1 >file && git add file &&
test_tick && git commit -m initial &&
git tag -s -m initial initial &&
git branch side &&
echo 2 >file && test_tick && git commit -a -m second &&
git tag -s -m second second &&
git checkout side &&
echo 3 >elif && git add elif &&
test_tick && git commit -m "third on side" &&
git checkout master &&
test_tick && git merge -S side &&
git tag -s -m merge merge &&
echo 4 >file && test_tick && git commit -a -S -m "fourth unsigned" &&
git tag -a -m fourth-unsigned fourth-unsigned &&
test_tick && git commit --amend -S -m "fourth signed" &&
git tag -s -m fourth fourth-signed &&
echo 5 >file && test_tick && git commit -a -m "fifth" &&
git tag fifth-unsigned &&
git config commit.gpgsign true &&
echo 6 >file && test_tick && git commit -a -m "sixth" &&
git tag -a -m sixth sixth-unsigned &&
test_tick && git rebase -f HEAD^^ && git tag -s -m 6th sixth-signed HEAD^ &&
git tag -m seventh -s seventh-signed &&
echo 8 >file && test_tick && git commit -a -m eighth &&
git tag -uB7227189 -m eighth eighth-signed-alt
'
test_expect_success GPG 'verify and show signatures' '
(
for tag in initial second merge fourth-signed sixth-signed seventh-signed
do
git verify-tag $tag 2>actual &&
grep "Good signature from" actual &&
! grep "BAD signature from" actual &&
echo $tag OK || exit 1
done
) &&
(
for tag in fourth-unsigned fifth-unsigned sixth-unsigned
do
test_must_fail git verify-tag $tag 2>actual &&
! grep "Good signature from" actual &&
! grep "BAD signature from" actual &&
echo $tag OK || exit 1
done
) &&
(
for tag in eighth-signed-alt
do
git verify-tag $tag 2>actual &&
grep "Good signature from" actual &&
! grep "BAD signature from" actual &&
grep "not certified" actual &&
echo $tag OK || exit 1
done
)
'
test_expect_success GPG 'detect fudged signature' '
git cat-file tag seventh-signed >raw &&
sed -e "/^tag / s/seventh/7th forged/" raw >forged1 &&
git hash-object -w -t tag forged1 >forged1.tag &&
test_must_fail git verify-tag $(cat forged1.tag) 2>actual1 &&
grep "BAD signature from" actual1 &&
! grep "Good signature from" actual1
'
test_expect_success GPG 'verify signatures with --raw' '
(
for tag in initial second merge fourth-signed sixth-signed seventh-signed
do
git verify-tag --raw $tag 2>actual &&
grep "GOODSIG" actual &&
! grep "BADSIG" actual &&
echo $tag OK || exit 1
done
) &&
(
for tag in fourth-unsigned fifth-unsigned sixth-unsigned
do
test_must_fail git verify-tag --raw $tag 2>actual &&
! grep "GOODSIG" actual &&
! grep "BADSIG" actual &&
echo $tag OK || exit 1
done
) &&
(
for tag in eighth-signed-alt
do
git verify-tag --raw $tag 2>actual &&
grep "GOODSIG" actual &&
! grep "BADSIG" actual &&
grep "TRUST_UNDEFINED" actual &&
echo $tag OK || exit 1
done
)
'
test_expect_success GPG 'verify multiple tags' '
tags="fourth-signed sixth-signed seventh-signed" &&
for i in $tags
do
git verify-tag -v --raw $i || return 1
done >expect.stdout 2>expect.stderr.1 &&
grep "^.GNUPG:." <expect.stderr.1 >expect.stderr &&
git verify-tag -v --raw $tags >actual.stdout 2>actual.stderr.1 &&
grep "^.GNUPG:." <actual.stderr.1 >actual.stderr &&
test_cmp expect.stdout actual.stdout &&
test_cmp expect.stderr actual.stderr
'
test_expect_success GPG 'verifying tag with --format' '
cat >expect <<-\EOF &&
tagname : fourth-signed
EOF
git verify-tag --format="tagname : %(tag)" "fourth-signed" >actual &&
test_cmp expect actual
'
test_expect_success GPG 'verifying a forged tag with --format should fail silently' '
>expect &&
test_must_fail git verify-tag --format="tagname : %(tag)" $(cat forged1.tag) >actual-forged &&
test_cmp expect actual-forged
'
test_done