From 2b1546c03cc3e02e51261fa38fe47a4f1b4e295b Mon Sep 17 00:00:00 2001 From: Justin Tobler Date: Thu, 26 Mar 2026 14:14:13 -0500 Subject: [PATCH] fast-import: add 'sign-if-invalid' mode to '--signed-tags=' With ee66c793f8 (fast-import: add mode to sign commits with invalid signatures, 2026-03-12), git-fast-import(1) learned to verify commit signatures during import and replace signatures that fail verification with a newly generated one. Extend the same behavior to signed tag objects by introducing a 'sign-if-invalid' mode for the '--signed-tags' option. Signed-off-by: Justin Tobler Signed-off-by: Junio C Hamano --- builtin/fast-import.c | 20 ++++++++++++--- t/t9306-fast-import-signed-tags.sh | 41 ++++++++++++++++++++++++++++-- 2 files changed, 55 insertions(+), 6 deletions(-) diff --git a/builtin/fast-import.c b/builtin/fast-import.c index 5e89829aea..783e0e7ab4 100644 --- a/builtin/fast-import.c +++ b/builtin/fast-import.c @@ -191,6 +191,7 @@ static const char *global_prefix; static enum sign_mode signed_tag_mode = SIGN_VERBATIM; static enum sign_mode signed_commit_mode = SIGN_VERBATIM; static const char *signed_commit_keyid; +static const char *signed_tag_keyid; /* Memory pools */ static struct mem_pool fi_mem_pool = { @@ -3110,6 +3111,19 @@ static void handle_tag_signature_if_invalid(struct strbuf *buf, strbuf_setlen(msg, sig_offset); + if (signed_tag_mode == SIGN_SIGN_IF_INVALID) { + strbuf_attach(&payload, sigc.payload, sigc.payload_len, + sigc.payload_len + 1); + sigc.payload = NULL; + strbuf_reset(&signature); + + if (sign_buffer(&payload, &signature, signed_tag_keyid, + SIGN_BUFFER_USE_DEFAULT_KEY)) + die(_("failed to sign tag object")); + + strbuf_addbuf(msg, &signature); + } + out: signature_check_clear(&sigc); strbuf_release(&signature); @@ -3142,6 +3156,7 @@ static void handle_tag_signature(struct strbuf *buf, struct strbuf *msg, const c /* Truncate the buffer to remove the signature */ strbuf_setlen(msg, sig_offset); break; + case SIGN_SIGN_IF_INVALID: case SIGN_STRIP_IF_INVALID: handle_tag_signature_if_invalid(buf, msg, sig_offset); break; @@ -3153,9 +3168,6 @@ static void handle_tag_signature(struct strbuf *buf, struct strbuf *msg, const c case SIGN_ABORT_IF_INVALID: die(_("'abort-if-invalid' is not a valid mode for " "git fast-import with --signed-tags=")); - case SIGN_SIGN_IF_INVALID: - die(_("'sign-if-invalid' is not a valid mode for " - "git fast-import with --signed-tags=")); default: BUG("invalid signed_tag_mode value %d from tag '%s'", signed_tag_mode, name); @@ -3749,7 +3761,7 @@ static int parse_one_option(const char *option) if (parse_sign_mode(option, &signed_commit_mode, &signed_commit_keyid)) usagef(_("unknown --signed-commits mode '%s'"), option); } else if (skip_prefix(option, "signed-tags=", &option)) { - if (parse_sign_mode(option, &signed_tag_mode, NULL)) + if (parse_sign_mode(option, &signed_tag_mode, &signed_tag_keyid)) usagef(_("unknown --signed-tags mode '%s'"), option); } else if (!strcmp(option, "quiet")) { show_stats = 0; diff --git a/t/t9306-fast-import-signed-tags.sh b/t/t9306-fast-import-signed-tags.sh index fd43b0b52a..bb4c8008ef 100755 --- a/t/t9306-fast-import-signed-tags.sh +++ b/t/t9306-fast-import-signed-tags.sh @@ -77,7 +77,7 @@ test_expect_success GPGSSH 'import SSH signed tag with --signed-tags=strip' ' test_grep ! "SSH SIGNATURE" out ' -for mode in strip-if-invalid +for mode in strip-if-invalid sign-if-invalid do test_expect_success GPG "import tag with no signature with --signed-tags=$mode" ' test_when_finished rm -rf import && @@ -117,7 +117,15 @@ do IMPORTED=$(git -C import rev-parse --verify refs/tags/openpgp-signed) && test $OPENPGP_SIGNED != $IMPORTED && git -C import cat-file tag "$IMPORTED" >actual && - test_grep ! -E "^-----BEGIN PGP SIGNATURE-----" actual && + + if test "$mode" = strip-if-invalid + then + test_grep ! -E "^-----BEGIN PGP SIGNATURE-----" actual + else + test_grep -E "^-----BEGIN PGP SIGNATURE-----" actual && + git -C import verify-tag "$IMPORTED" + fi && + test_must_be_empty log ' @@ -150,4 +158,33 @@ do ' done +test_expect_success GPGSSH 'sign invalid tag with explicit keyid' ' + test_when_finished rm -rf import && + git init import && + + git fast-export --signed-tags=verbatim ssh-signed >output && + + # Change the tag message, which invalidates the signature. The tag + # message length should not change though, otherwise the corresponding + # `data ` command would have to be changed too. + sed "s/SSH signed tag/SSH forged tag/" output >modified && + + # Configure the target repository with an invalid default signing key. + test_config -C import user.signingkey "not-a-real-key-id" && + test_config -C import gpg.format ssh && + test_config -C import gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" && + test_must_fail git -C import fast-import --quiet \ + --signed-tags=sign-if-invalid /dev/null 2>&1 && + + # Import using explicitly provided signing key. + git -C import fast-import --quiet \ + --signed-tags=sign-if-invalid="${GPGSSH_KEY_PRIMARY}" actual && + test_grep -E "^-----BEGIN SSH SIGNATURE-----" actual && + git -C import verify-tag "$IMPORTED" +' + test_done