git cat-file -p branchname:path/to/file/named/i-gaffed
which, when commit affed exists, will not return us information about a
file we are looking for but will instead tell us about commit affed.
Similarly, we should probably not treat
refs/tags/invalid/./../...../// ~^:/?*\\&[}/busted.lock-g049e0ef6
as a request for commit 050e0ef6 either.
Tighten up the parsing to make sure ${REFNAME} and ${INTEGER} are
present and valid.
Reported-by: Gabriel Amaral <gabriel-amaral@xxxxxxxxxx>
Signed-off-by: Elijah Newren <newren@xxxxxxxxx>
---
object-name.c | 55 ++++++++++++++++++++++++++++++++++++++++++++-
t/t6120-describe.sh | 22 ++++++++++++++++++
2 files changed, 76 insertions(+), 1 deletion(-)
diff --git a/object-name.c b/object-name.c
index e54ef1f621e..71207729f6f 100644
--- a/object-name.c
+++ b/object-name.c
@@ -1271,6 +1271,58 @@ static int peel_onion(struct repository *r, const char *name, int len,
return 0;
}
+/*
+ * Documentation/revisions.txt says:
+ * '<describeOutput>', e.g. 'v1.7.4.2-679-g3bee7fb'::
+ * Output from `git describe`; i.e. a closest tag, optionally
+ * followed by a dash and a number of commits, followed by a dash, a
+ * 'g', and an abbreviated object name.
+ *
+ * which means that the stuff before '-g${HASH}' needs to be a valid
+ * refname, a dash, and a non-negative integer. This function verifies
+ * that.
+ *
+ * In particular, we do not want to treat
+ * branchname:path/to/file/named/i-gaffed
+ * as a request for commit affed.
+ *
+ * More generally, we should probably not treat
+ * 'refs/heads/./../.../ ~^:/?*[////\\\&}/busted.lock-g050e0ef6ead'
+ * as a request for object 050e0ef6ead either.
+ *
+ * We are called with name[len] == '-' and name[len+1] == 'g', i.e.
+ * we are verifying ${REFNAME}-{INTEGER} part of the name.
+ */
+static int ref_and_count_parts_valid(const char *name, int len)
+{
+ struct strbuf sb;
+ const char *cp;
+ int flags = REFNAME_ALLOW_ONELEVEL;
+ int ret = 1;
+
+ /* Ensure we have at least one digit */
+ if (!isxdigit(name[len-1]))
+ return 0;
+
+ /* Skip over digits backwards until we get to the dash */
+ for (cp = name + len - 2; name < cp; cp--) {
+ if (*cp == '-')
+ break;
+ if (!isxdigit(*cp))
+ return 0;
+ }
+ /* Ensure we found the leading dash */
+ if (*cp != '-')
+ return 0;
+
+ len = cp - name;
+ strbuf_init(&sb, len);
+ strbuf_add(&sb, name, len);
+ ret = !check_refname_format(name, flags);
+ strbuf_release(&sb);
+ return ret;
+}
+
static int get_describe_name(struct repository *r,
const char *name, int len,
struct object_id *oid)
@@ -1284,7 +1336,8 @@ static int get_describe_name(struct repository *r,
/* We must be looking at g in "SOMETHING-g"
* for it to be describe output.
*/
- if (ch == 'g' && cp[-1] == '-') {
+ if (ch == 'g' && cp[-1] == '-' &&
+ ref_and_count_parts_valid(name, cp - 1 - name)) {
cp++;
len -= cp - name;
return get_short_oid(r,
diff --git a/t/t6120-describe.sh b/t/t6120-describe.sh
index 3f6160d702b..9217bd0fa89 100755
--- a/t/t6120-describe.sh
+++ b/t/t6120-describe.sh
@@ -725,4 +725,26 @@ test_expect_success '--exact-match does not show --always fallback' '
test_must_fail git describe --exact-match --always
'
+test_expect_success 'avoid being fooled by describe-like filename' '
+ test_when_finished rm out &&
+
+ git rev-parse --short HEAD >out &&
+ FILENAME=filename-g$(cat out) &&
+ touch $FILENAME &&
+ git add $FILENAME &&
+ git commit -m "Add $FILENAME" &&
+
+ git cat-file -t HEAD:$FILENAME >actual &&
+
+ echo blob >expect &&
+ test_cmp expect actual
+'
+
+test_expect_success 'do not be fooled by invalid describe format ' '
+ test_when_finished rm out &&
+
+ git rev-parse --short HEAD >out &&
+ test_must_fail git cat-file -t "refs/tags/super-invalid/./../...../ ~^:/?*[////\\\\\\&}/busted.lock-42-g"$(cat out)
+'
+
test_done
--
gitgitgadget
