[RFC,5/6] ssh signing: verify-tag/check_signature with tag date

Commit Message

Fabian Stelzer Oct. 15, 2021, 1:15 p.m. UTC

Passes tag date and tagger ident to to check_signature.
Implements the same tests as for verify-commit.

Signed-off-by: Fabian Stelzer <[e-mail]>
---
 t/t7031-verify-tag-signed-ssh.sh | 42 ++++++++++++++++++++++++++++++++
 tag.c                            | 12 +++++++--
 2 files changed, 52 insertions(+), 2 deletions(-)

Patch

diff --git a/t/t7031-verify-tag-signed-ssh.sh b/t/t7031-verify-tag-signed-ssh.sh
index 06c9dd6c93..1cb36b9ab8 100755
--- a/t/t7031-verify-tag-signed-ssh.sh
+++ b/t/t7031-verify-tag-signed-ssh.sh
@@ -48,6 +48,23 @@  test_expect_success GPGSSH 'create signed tags ssh' '
 	git tag -u"${GPGSSH_KEY_UNTRUSTED}" -m eighth eighth-signed-alt
 '
 
+test_expect_success GPGSSH,GPGSSH_VERIFYTIME 'create signed tags with keys having defined lifetimes' '
+	test_when_finished "test_unconfig commit.gpgsign" &&
+	test_config gpg.format ssh &&
+
+	echo expired >file && test_tick && git commit -a -m expired -S"${GPGSSH_KEY_EXPIRED}" &&
+	git tag -s -u "${GPGSSH_KEY_EXPIRED}" -m expired-signed expired-signed &&
+
+	echo notyetvalid >file && test_tick && git commit -a -m notyetvalid -S"${GPGSSH_KEY_NOTYETVALID}" &&
+	git tag -s -u "${GPGSSH_KEY_NOTYETVALID}" -m notyetvalid-signed notyetvalid-signed &&
+
+	echo timeboxedvalid >file && test_tick && git commit -a -m timeboxedvalid -S"${GPGSSH_KEY_TIMEBOXEDVALID}" &&
+	git tag -s -u "${GPGSSH_KEY_TIMEBOXEDVALID}" -m timeboxedvalid-signed timeboxedvalid-signed &&
+
+	echo timeboxedinvalid >file && test_tick && git commit -a -m timeboxedinvalid -S"${GPGSSH_KEY_TIMEBOXEDINVALID}" &&
+	git tag -s -u "${GPGSSH_KEY_TIMEBOXEDINVALID}" -m timeboxedinvalid-signed timeboxedinvalid-signed
+'
+
 test_expect_success GPGSSH 'verify and show ssh signatures' '
 	test_config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
 	(
@@ -80,6 +97,31 @@  test_expect_success GPGSSH 'verify and show ssh signatures' '
 	)
 '
 
+test_expect_success GPGSSH,GPGSSH_VERIFYTIME 'verify-tag exits failure on expired signature key' '
+	test_config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
+	test_must_fail git verify-tag expired-signed 2>actual &&
+	! grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual
+'
+
+test_expect_success GPGSSH,GPGSSH_VERIFYTIME 'verify-tag exits failure on not yet valid signature key' '
+	test_config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
+	test_must_fail git verify-tag notyetvalid-signed 2>actual &&
+	! grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual
+'
+
+test_expect_success GPGSSH,GPGSSH_VERIFYTIME 'verify-tag succeeds with tag date and key validity matching' '
+	test_config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
+	git verify-tag timeboxedvalid-signed 2>actual &&
+	grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual &&
+	! grep "${GPGSSH_BAD_SIGNATURE}" actual
+'
+
+test_expect_success GPGSSH,GPGSSH_VERIFYTIME 'verify-tag failes with tag date outside of key validity' '
+	test_config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
+	test_must_fail git verify-tag timeboxedinvalid-signed 2>actual &&
+	! grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual
+'
+
 test_expect_success GPGSSH 'detect fudged ssh signature' '
 	test_config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
 	git cat-file tag seventh-signed >raw &&
diff --git a/tag.c b/tag.c
index 3459a0867c..1868e6b51d 100644
--- a/tag.c
+++ b/tag.c
@@ -16,6 +16,8 @@  static int run_gpg_verify(const char *buf, unsigned long size, unsigned flags)
 	struct strbuf payload = STRBUF_INIT;
 	struct strbuf signature = STRBUF_INIT;
 	int ret;
+	struct strbuf payload_signer = STRBUF_INIT;
+	timestamp_t payload_timestamp = 0;
 
 	memset(&sigc, 0, sizeof(sigc));
 
@@ -25,8 +27,13 @@  static int run_gpg_verify(const char *buf, unsigned long size, unsigned flags)
 		return error("no signature found");
 	}
 
-	ret = check_signature(payload.buf, payload.len, 0, NULL, signature.buf,
-				signature.len, &sigc);
+	if (parse_signed_buffer_metadata(payload.buf, "tagger", &payload_timestamp,
+					 &payload_signer))
+		return error(_("failed to parse timestamp and signer info from payload"));
+
+	ret = check_signature(payload.buf, payload.len, payload_timestamp,
+			      &payload_signer, signature.buf, signature.len,
+			      &sigc);
 
 	if (!(flags & GPG_VERIFY_OMIT_STATUS))
 		print_signature_buffer(&sigc, flags);
@@ -34,6 +41,7 @@  static int run_gpg_verify(const char *buf, unsigned long size, unsigned flags)
 	signature_check_clear(&sigc);
 	strbuf_release(&payload);
 	strbuf_release(&signature);
+	strbuf_release(&payload_signer);
 	return ret;
 }