From 835d645f4052551c5c1829c37a07c882f2260f65 Mon Sep 17 00:00:00 2001
From: Phil Sutter <phil@nwl.cc>
Date: Mon, 2 Dec 2019 23:08:07 +0100
Subject: [libnftnl PATCH] flowtable: Correctly check realloc() call

If realloc() fails, it returns NULL but the original pointer is
untouchted and therefore still has to be freed. Unconditionally
overwriting the old pointer is therefore a bad idea, use a temporary
variable instead.

Fixes: 7f99639dd9217 ("flowtable: device array dynamic allocation")
Signed-off-by: Phil Sutter <phil@nwl.cc>
Acked-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 src/flowtable.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/src/flowtable.c b/src/flowtable.c
index db319434b51c0..9ba3b6d9a3404 100644
--- a/src/flowtable.c
+++ b/src/flowtable.c
@@ -388,7 +388,7 @@ static int nftnl_flowtable_parse_hook_cb(const struct nlattr *attr, void *data)
 static int nftnl_flowtable_parse_devs(struct nlattr *nest,
 				      struct nftnl_flowtable *c)
 {
-	const char **dev_array;
+	const char **dev_array, **tmp;
 	int len = 0, size = 8;
 	struct nlattr *attr;
 
@@ -401,14 +401,13 @@ static int nftnl_flowtable_parse_devs(struct nlattr *nest,
 			goto err;
 		dev_array[len++] = strdup(mnl_attr_get_str(attr));
 		if (len >= size) {
-			dev_array = realloc(dev_array,
-					    size * 2 * sizeof(char *));
-			if (!dev_array)
+			tmp = realloc(dev_array, size * 2 * sizeof(char *));
+			if (!tmp)
 				goto err;
 
 			size *= 2;
-			memset(&dev_array[len], 0,
-			       (size - len) * sizeof(char *));
+			memset(&tmp[len], 0, (size - len) * sizeof(char *));
+			dev_array = tmp;
 		}
 	}
 
-- 
2.24.0