Change the hardcoded minimum tag length size to vary based on whether
we're operating in the SHA-1 or SHA-256 mode, and update the "mktag"
documentation, tests and code comments to reflect that this command
can take either SHA-1 or SHA-256 input.
Let's make the code more self-documenting by verbosely inlining what a
minimum tag looks like. The fixed-string strlen() will be optimized
away by any modern compiler. This also future-proofs us for any future
hash function transition.
Then change the tests amended in acb49d1cc8b (t3800: make hash-size
independent, 2019-08-18) even more for SHA-256. Some of the tests were
failing for the wrong reasons. E.g. yes <some sha-1 length garbage> is
an invalid SHA-1, but we should test <some sha256 length garbage> when
under SHA-256. For testing an invalid non-hexadecimal object ID let's
use ROT13.
For the "object line label check" test the "139e9b339..." SHA-1 didn't
exist, but what's actually being tested there is getting "xxxxxx"
instead of "object", so let's provide a valid SHA there
instead. There's no need to make or hardcode a nonexisting object ID.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@xxxxxxxxx>
---
Documentation/git-mktag.txt | 2 +-
builtin/mktag.c | 26 +++++++++++++-------
t/t3800-mktag.sh | 47 ++++++++++++++++++++++++++-----------
3 files changed, 52 insertions(+), 23 deletions(-)
diff --git a/Documentation/git-mktag.txt b/Documentation/git-mktag.txt
index fa6a7561236..bbcc0a086bf 100644
--- a/Documentation/git-mktag.txt
+++ b/Documentation/git-mktag.txt
@@ -23,7 +23,7 @@ Tag Format
A tag signature file, to be fed to this command's standard input,
has a very simple fixed format: four lines of
- object <sha1>
+ object <sha>
type <typename>
tag <tagname>
tagger <tagger>
diff --git a/builtin/mktag.c b/builtin/mktag.c
index 4982d3a93ef..3fa17243e34 100644
--- a/builtin/mktag.c
+++ b/builtin/mktag.c
@@ -5,13 +5,15 @@
/*
* A signature file has a very simple fixed format: four lines
- * of "object <sha1>" + "type <typename>" + "tag <tagname>" +
+ * of "object <sha>" + "type <typename>" + "tag <tagname>" +
* "tagger <committer>", followed by a blank line, a free-form tag
* message and a signature block that git itself doesn't care about,
* but that can be verified with gpg or similar.
*
- * The first four lines are guaranteed to be at least 83 bytes:
- * "object <sha1>\n" is 48 bytes, "type tag\n" at 9 bytes is the
+ * The first four lines are guaranteed to be either 83 or 107 bytes;
+ * depending on whether we're referencing a SHA-1 or SHA-256 tag.
+ *
+ * "object <sha1>\n" is 48 or a 72 bytes, "type tag\n" at 9 bytes is the
* shortest possible type-line, "tag .\n" at 6 bytes is the shortest
* single-character-tag line, and "tagger . <> 0 +0000\n" at 20 bytes is
* the shortest possible tagger-line.
@@ -46,9 +48,17 @@ static int verify_tag(char *buffer, unsigned long size)
struct object_id oid;
const char *object, *type_line, *tag_line, *tagger_line, *lb, *rb, *p;
size_t len;
-
- if (size < 84)
- return error("wanna fool me ? you obviously got the size wrong !");
+ int minimum_size =
+ /* Minimum possible input, see t/t3800-mktag.sh */
+ strlen("object ") + the_hash_algo->hexsz + strlen("\n") +
+ strlen("type tag\n") +
+ strlen("tag x\n") +
+ strlen("tagger . <> 0 +0000\n") +
+ strlen("\n");
+
+ if (size < minimum_size)
+ return error("got %"PRIuMAX" bytes of input, need at least %d bytes",
+ size, minimum_size);
buffer[size] = 0;
@@ -58,7 +68,7 @@ static int verify_tag(char *buffer, unsigned long size)
return error("char%d: does not start with \"object \"", 0);
if (parse_oid_hex(object + 7, &oid, &p))
- return error("char%d: could not get SHA1 hash", 7);
+ return error("char%d: expected object ID, got garbage", 7);
/* Verify type line */
type_line = p + 1;
@@ -166,7 +176,7 @@ int cmd_mktag(int argc, const char **argv, const char *prefix)
}
/* Verify it for some basic sanity: it needs to start with
- "object <sha1>\ntype\ntagger " */
+ "object <sha>\ntype\ntagger " */
if (verify_tag(buf.buf, buf.len) < 0)
die("invalid tag signature file");
diff --git a/t/t3800-mktag.sh b/t/t3800-mktag.sh
index d696aa4e52e..93a19bb8df9 100755
--- a/t/t3800-mktag.sh
+++ b/t/t3800-mktag.sh
@@ -26,24 +26,42 @@ test_expect_success 'setup' '
echo Hello >A &&
git update-index --add A &&
git commit -m "Initial commit" &&
- head=$(git rev-parse --verify HEAD)
+ head=$(git rev-parse --verify HEAD) &&
+
+ git tag -m"some tag" annotated &&
+ annotated=$(git rev-parse --verify annotated)
'
############################################################
# 1. length check
-
-cat >tag.sig <<EOF
-too short for a tag
-EOF
-
-check_verify_failure 'Tag object length check' \
- '^error: .*size wrong.*$'
+for objType in t ta tag
+do
+ cat >tag.sig <<-EOF
+ object $annotated
+ type $objType
+ tag x
+ tagger . <> 0 +0000
+
+ EOF
+ len=$(wc -c tag.sig)
+
+ if test $objType = "tag"
+ then
+ test_expect_success "Tag object length check $len passed" '
+ git mktag <tag.sig >.git/refs/tags/x 2>message &&
+ git rev-parse refs/tags/x
+ '
+ else
+ check_verify_failure "Tag object length check on length $len" \
+ '^error: got .* bytes of input, need at least'
+ fi
+done
############################################################
# 2. object line label check
cat >tag.sig <<EOF
-xxxxxx 139e9b33986b1c2670fff52c5067603117b3e895
+xxxxxx $head
type tag
tag mytag
tagger . <> 0 +0000
@@ -53,17 +71,18 @@ EOF
check_verify_failure '"object" line label check' '^error: char0: .*"object "$'
############################################################
-# 3. object line SHA1 check
+# 3. object line SHA check
+invalid_sha=$(echo $head | tr A-Za-z N-ZA-Mn-za-m)
cat >tag.sig <<EOF
-object zz9e9b33986b1c2670fff52c5067603117b3e895
+object $invalid_sha
type tag
tag mytag
tagger . <> 0 +0000
EOF
-check_verify_failure '"object" line SHA1 check' '^error: char7: .*SHA1 hash$'
+check_verify_failure '"object" line object check' '^error: char7: .*expected object ID, got garbage'
############################################################
# 4. type line label check
@@ -125,7 +144,7 @@ check_verify_failure '"type" line type-name length check' \
'^error: char.*: type too long$'
############################################################
-# 9. verify object (SHA1/type) check
+# 9. verify object (SHA/type) check
cat >tag.sig <<EOF
object $(test_oid deadbeef)
@@ -135,7 +154,7 @@ tagger . <> 0 +0000
EOF
-check_verify_failure 'verify object (SHA1/type) check' \
+check_verify_failure 'verify object (SHA/type) check' \
'^error: char7: could not verify object.*$'
############################################################
--
2.29.2.222.g5d2a92d10f8
