From 42d4e1d1128fa1cb56032ac58f65ea3dd1296a9a Mon Sep 17 00:00:00 2001 From: "brian m. carlson" Date: Sat, 22 Feb 2020 20:17:42 +0000 Subject: commit: use expected signature header for SHA-256 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 Signed-off-by: Junio C Hamano diff --git a/builtin/commit.c b/builtin/commit.c index 7ba33a3..798d362 100644 --- a/builtin/commit.c +++ b/builtin/commit.c @@ -1659,7 +1659,7 @@ int cmd_commit(int argc, const char **argv, const char *prefix) } if (amend) { - const char *exclude_gpgsig[2] = { "gpgsig", NULL }; + const char *exclude_gpgsig[3] = { "gpgsig", "gpgsig-sha256", NULL }; extra = read_commit_extra_headers(current_head, exclude_gpgsig); } else { struct commit_extra_header **tail = &extra; diff --git a/commit.c b/commit.c index a6cfa41..534e14f 100644 --- a/commit.c +++ b/commit.c @@ -961,14 +961,22 @@ cleanup_return: return ret; } -static const char gpg_sig_header[] = "gpgsig"; -static const int gpg_sig_header_len = sizeof(gpg_sig_header) - 1; +/* + * Indexed by hash algorithm identifier. + */ +static const char *gpg_sig_headers[] = { + NULL, + "gpgsig", + "gpgsig-sha256", +}; static int do_sign_commit(struct strbuf *buf, const char *keyid) { struct strbuf sig = STRBUF_INIT; int inspos, copypos; const char *eoh; + const char *gpg_sig_header = gpg_sig_headers[hash_algo_by_ptr(the_hash_algo)]; + int gpg_sig_header_len = strlen(gpg_sig_header); /* find the end of the header */ eoh = strstr(buf->buf, "\n\n"); @@ -1010,6 +1018,8 @@ int parse_signed_commit(const struct commit *commit, const char *buffer = get_commit_buffer(commit, &size); int in_signature, saw_signature = -1; const char *line, *tail; + const char *gpg_sig_header = gpg_sig_headers[hash_algo_by_ptr(the_hash_algo)]; + int gpg_sig_header_len = strlen(gpg_sig_header); line = buffer; tail = buffer + size; @@ -1056,11 +1066,17 @@ int remove_signature(struct strbuf *buf) if (in_signature && line[0] == ' ') sig_end = next; - else if (starts_with(line, gpg_sig_header) && - line[gpg_sig_header_len] == ' ') { - sig_start = line; - sig_end = next; - in_signature = 1; + else if (starts_with(line, "gpgsig")) { + int i; + for (i = 1; i < GIT_HASH_NALGOS; i++) { + const char *p; + if (skip_prefix(line, gpg_sig_headers[i], &p) && + *p == ' ') { + sig_start = line; + sig_end = next; + in_signature = 1; + } + } } else { if (*line == '\n') /* dump the whole remainder of the buffer */ diff --git a/sequencer.c b/sequencer.c index ba90a51..cbd920a 100644 --- a/sequencer.c +++ b/sequencer.c @@ -1321,7 +1321,7 @@ static int try_to_commit(struct repository *r, return -1; if (flags & AMEND_MSG) { - const char *exclude_gpgsig[] = { "gpgsig", NULL }; + const char *exclude_gpgsig[] = { "gpgsig", "gpgsig-sha256", NULL }; const char *out_enc = get_commit_output_encoding(); const char *message = logmsg_reencode(current_head, NULL, out_enc); diff --git a/t/t1450-fsck.sh b/t/t1450-fsck.sh index 02478bc..70a8307 100755 --- a/t/t1450-fsck.sh +++ b/t/t1450-fsck.sh @@ -133,6 +133,30 @@ test_expect_success 'other worktree HEAD link pointing at a funny place' ' test_i18ngrep "worktrees/other/HEAD points to something strange" out ' +test_expect_success 'commit with multiple signatures is okay' ' + git cat-file commit HEAD >basis && + cat >sigs <<-EOF && + gpgsig -----BEGIN PGP SIGNATURE----- + VGhpcyBpcyBub3QgcmVhbGx5IGEgc2lnbmF0dXJlLg== + -----END PGP SIGNATURE----- + gpgsig-sha256 -----BEGIN PGP SIGNATURE----- + VGhpcyBpcyBub3QgcmVhbGx5IGEgc2lnbmF0dXJlLg== + -----END PGP SIGNATURE----- + EOF + sed -e "/^committer/q" basis >okay && + cat sigs >>okay && + echo >>okay && + sed -e "1,/^$/d" basis >>okay && + cat okay && + new=$(git hash-object -t commit -w --stdin out && + cat out && + ! grep "commit $new" out +' + test_expect_success 'email without @ is okay' ' git cat-file commit HEAD >basis && sed "s/@/AT/" basis >okay && diff --git a/t/t7510-signed-commit.sh b/t/t7510-signed-commit.sh index 0c06d22..6baaa1a 100755 --- a/t/t7510-signed-commit.sh +++ b/t/t7510-signed-commit.sh @@ -6,6 +6,11 @@ GNUPGHOME_NOT_USED=$GNUPGHOME . "$TEST_DIRECTORY/lib-gpg.sh" test_expect_success GPG 'create signed commits' ' + test_oid_cache <<-\EOF && + header sha1:gpgsig + header sha256:gpgsig-sha256 + EOF + test_when_finished "test_unconfig commit.gpgsign" && echo 1 >file && git add file && @@ -155,6 +160,11 @@ test_expect_success GPG 'verify signatures with --raw' ' ) ' +test_expect_success GPG 'proper header is used for hash algorithm' ' + git cat-file commit fourth-signed >output && + grep "^$(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 && @@ -162,7 +172,7 @@ test_expect_success GPG 'show signed commit with signature' ' 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 && + grep -v "^ " cat | grep -v "^$(test_oid header) " >cat.commit && test_cmp show.commit commit && test_cmp show.gpg verify.2 && test_cmp cat.commit verify.1 @@ -299,10 +309,10 @@ test_expect_success GPG 'check config gpg.format values' ' test_expect_success GPG 'detect fudged commit with double signature' ' sed -e "/gpgsig/,/END PGP/d" forged1 >double-base && sed -n -e "/gpgsig/,/END PGP/p" forged1 | \ - sed -e "s/^gpgsig//;s/^ //" | gpg --dearmor >double-sig1.sig && + sed -e "s/^$(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/^/gpgsig /;2,\$s/^/ /" \ + 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 && -- cgit v0.10.2-6-g49f6