diff mbox series

hash-object: prefix_filename() returns allocated memory these days

Message ID xmqqsfyg82b5.fsf@gitster.g (mailing list archive)
State Accepted
Commit a5221ea92e36051fcecdf479ec34279cfb0812cc
Headers show
Series hash-object: prefix_filename() returns allocated memory these days | expand

Commit Message

Junio C Hamano Sept. 7, 2021, 10:10 p.m. UTC
Back when a1be47e4 (hash-object: fix buffer reuse with --path in a
subdirectory, 2017-03-20) was written, the prefix_filename() helper
used a static piece of memory to the caller, making the caller
responsible for copying it, if it wants to keep it across another
call to the same function.  Two callers of the prefix_filename() in
hash-object were made to xstrdup() the value obtained from it.

But in the same series, when e4da43b1 (prefix_filename: return newly
allocated string, 2017-03-20) changed the rule to gave the caller
possession of the memory, we forgot to revert one of the xstrdup()
changes, allowing the returned value to leak.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---

 * "git show -W e4da43b1 builtin/hash-object.c" made me curious.

 builtin/hash-object.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Jeff King Sept. 8, 2021, 9:42 a.m. UTC | #1
On Tue, Sep 07, 2021 at 03:10:22PM -0700, Junio C Hamano wrote:

> Back when a1be47e4 (hash-object: fix buffer reuse with --path in a
> subdirectory, 2017-03-20) was written, the prefix_filename() helper
> used a static piece of memory to the caller, making the caller
> responsible for copying it, if it wants to keep it across another
> call to the same function.  Two callers of the prefix_filename() in
> hash-object were made to xstrdup() the value obtained from it.
> 
> But in the same series, when e4da43b1 (prefix_filename: return newly
> allocated string, 2017-03-20) changed the rule to gave the caller
> possession of the memory, we forgot to revert one of the xstrdup()
> changes, allowing the returned value to leak.

Good catch. The patch looks obviously correct to me.

-Peff
diff mbox series

Patch

diff --git c/builtin/hash-object.c w/builtin/hash-object.c
index 640ef4ded5..084cba204b 100644
--- c/builtin/hash-object.c
+++ w/builtin/hash-object.c
@@ -117,7 +117,7 @@  int cmd_hash_object(int argc, const char **argv, const char *prefix)
 		prefix = setup_git_directory_gently(&nongit);
 
 	if (vpath && prefix)
-		vpath = xstrdup(prefix_filename(prefix, vpath));
+		vpath = prefix_filename(prefix, vpath);
 
 	git_config(git_default_config, NULL);