From e7366db80740d34d2fe4ba8d12ef86a423e66280 Mon Sep 17 00:00:00 2001
From: Phil Sutter <phil@nwl.cc>
Date: Wed, 31 Jan 2024 14:58:17 +0100
Subject: [PATCH] libxtables: Fix memleak of matches' udata

If the extension specifies a non-zero udata_size, field 'udata' points
to an allocated buffer which needs to be freed upon extension deinit.

Interestingly, this bug was identified by ASAN and missed by valgrind.

Fixes: 2dba676b68ef8 ("extensions: support for per-extension instance "global" variable space")
Signed-off-by: Phil Sutter <phil@nwl.cc>
---
 libxtables/xtables.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/libxtables/xtables.c b/libxtables/xtables.c
index b4339e8d..856bfae8 100644
--- a/libxtables/xtables.c
+++ b/libxtables/xtables.c
@@ -1420,6 +1420,10 @@ void xtables_rule_matches_free(struct xtables_rule_match **matches)
 			free(matchp->match->m);
 			matchp->match->m = NULL;
 		}
+		if (matchp->match->udata_size) {
+			free(matchp->match->udata);
+			matchp->match->udata = NULL;
+		}
 		if (matchp->match == matchp->match->next) {
 			free(matchp->match);
 			matchp->match = NULL;
-- 
2.43.4