fast-import: add '--signed-commits=<mode>' option

A '--signed-commits=<mode>' option is already available when using
`git fast-export` to decide what should be done at export time about
commit signatures. At import time though, there is no option, or
other way, in `git fast-import` to decide about commit signatures.

To remediate that, let's add a '--signed-commits=<mode>' option to
`git fast-import` too.

For now the supported <mode>s are the same as those supported by
`git fast-export`.

The code responsible for consuming a signature is refactored into
the import_one_signature() and discard_one_signature() functions,
which makes it easier to follow the logic and add new modes in the
future.

In the 'strip' and 'warn-strip' modes, we deliberately use
discard_one_signature() to discard the signature without parsing it.
This ensures that even malformed signatures, which would cause the
parser to fail, can be successfully stripped from a commit.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
main
Christian Couder 2025-09-17 20:14:27 +02:00 committed by Junio C Hamano
parent 2f8fd208c3
commit eaaddf5791
4 changed files with 164 additions and 9 deletions

View File

@ -66,6 +66,11 @@ OPTIONS
remote-helpers that use the `import` capability, as they are
already trusted to run their own code.

--signed-commits=(verbatim|warn-verbatim|warn-strip|strip|abort)::
Specify how to handle signed commits. Behaves in the same way
as the same option in linkgit:git-fast-export[1], except that
default is 'verbatim' (instead of 'abort').

Options for Frontends
~~~~~~~~~~~~~~~~~~~~~


View File

@ -188,6 +188,8 @@ static int global_argc;
static const char **global_argv;
static const char *global_prefix;

static enum sign_mode signed_commit_mode = SIGN_VERBATIM;

/* Memory pools */
static struct mem_pool fi_mem_pool = {
.block_alloc = 2*1024*1024 - sizeof(struct mp_block),
@ -2752,6 +2754,15 @@ static void parse_one_signature(struct signature_data *sig, const char *v)
parse_data(&sig->data, 0, NULL);
}

static void discard_one_signature(void)
{
struct strbuf data = STRBUF_INIT;

read_next_command();
parse_data(&data, 0, NULL);
strbuf_release(&data);
}

static void add_gpgsig_to_commit(struct strbuf *commit_data,
const char *header,
struct signature_data *sig)
@ -2785,6 +2796,22 @@ static void store_signature(struct signature_data *stored_sig,
}
}

static void import_one_signature(struct signature_data *sig_sha1,
struct signature_data *sig_sha256,
const char *v)
{
struct signature_data sig = { NULL, NULL, STRBUF_INIT };

parse_one_signature(&sig, v);

if (!strcmp(sig.hash_algo, "sha1"))
store_signature(sig_sha1, &sig, "SHA-1");
else if (!strcmp(sig.hash_algo, "sha256"))
store_signature(sig_sha256, &sig, "SHA-256");
else
die(_("parse_one_signature() returned unknown hash algo"));
}

static void parse_new_commit(const char *arg)
{
static struct strbuf msg = STRBUF_INIT;
@ -2817,19 +2844,32 @@ static void parse_new_commit(const char *arg)
if (!committer)
die("Expected committer but didn't get one");

/* Process signatures (up to 2: one "sha1" and one "sha256") */
while (skip_prefix(command_buf.buf, "gpgsig ", &v)) {
struct signature_data sig = { NULL, NULL, STRBUF_INIT };
switch (signed_commit_mode) {

parse_one_signature(&sig, v);
/* First, modes that don't need the signature to be parsed */
case SIGN_ABORT:
die("encountered signed commit; use "
"--signed-commits=<mode> to handle it");
case SIGN_WARN_STRIP:
warning(_("stripping a commit signature"));
/* fallthru */
case SIGN_STRIP:
discard_one_signature();
break;

if (!strcmp(sig.hash_algo, "sha1"))
store_signature(&sig_sha1, &sig, "SHA-1");
else if (!strcmp(sig.hash_algo, "sha256"))
store_signature(&sig_sha256, &sig, "SHA-256");
else
BUG("parse_one_signature() returned unknown hash algo");
/* Second, modes that parse the signature */
case SIGN_WARN_VERBATIM:
warning(_("importing a commit signature verbatim"));
/* fallthru */
case SIGN_VERBATIM:
import_one_signature(&sig_sha1, &sig_sha256, v);
break;

/* Third, BUG */
default:
BUG("invalid signed_commit_mode value %d", signed_commit_mode);
}
read_next_command();
}

@ -3501,6 +3541,9 @@ static int parse_one_option(const char *option)
option_active_branches(option);
} else if (skip_prefix(option, "export-pack-edges=", &option)) {
option_export_pack_edges(option);
} else if (skip_prefix(option, "signed-commits=", &option)) {
if (parse_sign_mode(option, &signed_commit_mode))
usagef(_("unknown --signed-commits mode '%s'"), option);
} else if (!strcmp(option, "quiet")) {
show_stats = 0;
quiet = 1;

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@ -1032,6 +1032,7 @@ integration_tests = [
't9302-fast-import-unpack-limit.sh',
't9303-fast-import-compression.sh',
't9304-fast-import-marks.sh',
't9305-fast-import-signatures.sh',
't9350-fast-export.sh',
't9351-fast-export-anonymize.sh',
't9400-git-cvsserver-server.sh',

106
t/t9305-fast-import-signatures.sh Executable file
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@ -0,0 +1,106 @@
#!/bin/sh

test_description='git fast-import --signed-commits=<mode>'

GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main

. ./test-lib.sh
. "$TEST_DIRECTORY/lib-gpg.sh"

test_expect_success 'set up unsigned initial commit and import repo' '
test_commit first &&
git init new
'

test_expect_success GPG 'set up OpenPGP signed commit' '
git checkout -b openpgp-signing main &&
echo "Content for OpenPGP signing." >file-sign &&
git add file-sign &&
git commit -S -m "OpenPGP signed commit" &&
OPENPGP_SIGNING=$(git rev-parse --verify openpgp-signing)
'

test_expect_success GPG 'import OpenPGP signature with --signed-commits=verbatim' '
git fast-export --signed-commits=verbatim openpgp-signing >output &&
git -C new fast-import --quiet --signed-commits=verbatim <output >log 2>&1 &&
IMPORTED=$(git -C new rev-parse --verify refs/heads/openpgp-signing) &&
test $OPENPGP_SIGNING = $IMPORTED &&
test_must_be_empty log
'

test_expect_success GPGSM 'set up X.509 signed commit' '
git checkout -b x509-signing main &&
test_config gpg.format x509 &&
test_config user.signingkey $GIT_COMMITTER_EMAIL &&
echo "Content for X.509 signing." >file-sign &&
git add file-sign &&
git commit -S -m "X.509 signed commit" &&
X509_SIGNING=$(git rev-parse HEAD)
'

test_expect_success GPGSM 'import X.509 signature fails with --signed-commits=abort' '
git fast-export --signed-commits=verbatim x509-signing >output &&
test_must_fail git -C new fast-import --quiet --signed-commits=abort <output
'

test_expect_success GPGSM 'import X.509 signature with --signed-commits=warn-verbatim' '
git -C new fast-import --quiet --signed-commits=warn-verbatim <output >log 2>&1 &&
IMPORTED=$(git -C new rev-parse --verify refs/heads/x509-signing) &&
test $X509_SIGNING = $IMPORTED &&
test_grep "importing a commit signature" log
'

test_expect_success GPGSSH 'set up SSH signed commit' '
git checkout -b ssh-signing main &&
test_config gpg.format ssh &&
test_config user.signingkey "${GPGSSH_KEY_PRIMARY}" &&
echo "Content for SSH signing." >file-sign &&
git add file-sign &&
git commit -S -m "SSH signed commit" &&
SSH_SIGNING=$(git rev-parse HEAD)
'

test_expect_success GPGSSH 'strip SSH signature with --signed-commits=strip' '
git fast-export --signed-commits=verbatim ssh-signing >output &&
git -C new fast-import --quiet --signed-commits=strip <output >log 2>&1 &&
IMPORTED=$(git -C new rev-parse --verify refs/heads/ssh-signing) &&
test $SSH_SIGNING != $IMPORTED &&
git -C new cat-file commit "$IMPORTED" >actual &&
test_grep ! -E "^gpgsig" actual &&
test_must_be_empty log
'

test_expect_success GPG 'setup a commit with dual OpenPGP signatures on its SHA-1 and SHA-256 formats' '
# Create a signed SHA-256 commit
git init --object-format=sha256 explicit-sha256 &&
git -C explicit-sha256 config extensions.compatObjectFormat sha1 &&
git -C explicit-sha256 checkout -b dual-signed &&
test_commit -C explicit-sha256 A &&
echo B >explicit-sha256/B &&
git -C explicit-sha256 add B &&
test_tick &&
git -C explicit-sha256 commit -S -m "signed" B &&
SHA256_B=$(git -C explicit-sha256 rev-parse dual-signed) &&

# Create the corresponding SHA-1 commit
SHA1_B=$(git -C explicit-sha256 rev-parse --output-object-format=sha1 dual-signed) &&

# Check that the resulting SHA-1 commit has both signatures
git -C explicit-sha256 cat-file -p $SHA1_B >out &&
test_grep -E "^gpgsig " out &&
test_grep -E "^gpgsig-sha256 " out
'

test_expect_success GPG 'strip both OpenPGP signatures with --signed-commits=warn-strip' '
git -C explicit-sha256 fast-export --signed-commits=verbatim dual-signed >output &&
test_grep -E "^gpgsig sha1 openpgp" output &&
test_grep -E "^gpgsig sha256 openpgp" output &&
git -C new fast-import --quiet --signed-commits=warn-strip <output >log 2>&1 &&
git -C new cat-file commit refs/heads/dual-signed >actual &&
test_grep ! -E "^gpgsig " actual &&
test_grep ! -E "^gpgsig-sha256 " actual &&
test_grep "stripping a commit signature" log >out &&
test_line_count = 2 out
'

test_done