From: Karthik Nayak <karthik.188@gmail.com>
Date: Mon, 19 May 2025 09:58:08 +0000 (+0200)
Subject: send-pack: fix memory leak around duplicate refs
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=77188b5bbaf1f77963968ea3acedda3108102b18;p=thirdparty%2Fgit.git

send-pack: fix memory leak around duplicate refs

The 'git-send-pack(1)' allows users to push objects to a remote
repository and explicitly list the references to be pushed. The status
of each reference pushed is captured into a list mapped by refname.

If a reference fails to be updated, its error message is captured in the
`ref->remote_status` field. While the command allows duplicate ref
inputs, the list doesn't accommodate this behavior as a particular
refname is linked to a single `struct ref*` element. So if the user
inputs a reference twice like:

  git send-pack remote.git A:foo B:foo

where the user is trying to update the same reference 'foo' twice and
the reference fails to be updated, we first fill `ref->remote_status`
with error message for the input 'A:foo' then we override the same field
with the error message for 'B:foo'. This override happens without first
free'ing the previous value. Fix this leak.

The current tests already incorporate the above example, but in the test
'A:foo' succeeds while 'B:foo' fails, meaning that the memory leak isn't
triggered. Add a new test with multiple duplicates.

Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---

diff --git a/send-pack.c b/send-pack.c
index 86592ce526..e2faa25b98 100644
--- a/send-pack.c
+++ b/send-pack.c
@@ -257,6 +257,13 @@ static int receive_status(struct repository *r,
 				refname);
 			continue;
 		}
+
+		/*
+		 * Clients sending duplicate refs can cause the same value
+		 * to be overridden, causing a memory leak.
+		 */
+		free(hint->remote_status);
+
 		if (!strcmp(head, "ng")) {
 			hint->status = REF_STATUS_REMOTE_REJECT;
 			if (p)
diff --git a/t/t5408-send-pack-stdin.sh b/t/t5408-send-pack-stdin.sh
index 526a675045..45fb20179b 100755
--- a/t/t5408-send-pack-stdin.sh
+++ b/t/t5408-send-pack-stdin.sh
@@ -73,6 +73,12 @@ test_expect_success 'cmdline refs written in order' '
 	verify_push A foo
 '
 
+test_expect_success 'cmdline refs with multiple duplicates' '
+	clear_remote &&
+	test_must_fail git send-pack remote.git A:foo B:foo C:foo &&
+	verify_push A foo
+'
+
 test_expect_success '--stdin refs come after cmdline' '
 	clear_remote &&
 	echo A:foo >input &&