From 2facd747b6bbcd3716841e6213b7b9e9b94c556a Mon Sep 17 00:00:00 2001
From: Phil Sutter <psutter@redhat.com>
Date: Fri, 6 Dec 2019 17:31:16 +0100
Subject: [PATCH] chain: Correctly check realloc() call

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1778952
Upstream Status: libnftnl commit d95a703746d53

commit d95a703746d5394d56a9f464e343594e4882da0d
Author: Phil Sutter <phil@nwl.cc>
Date:   Mon Dec 2 23:12:34 2019 +0100

    chain: 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: e3ac19b5ec162 ("chain: multi-device support")
    Signed-off-by: Phil Sutter <phil@nwl.cc>
    Acked-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 src/chain.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/src/chain.c b/src/chain.c
index 9cc8735..b9a16fc 100644
--- a/src/chain.c
+++ b/src/chain.c
@@ -605,7 +605,7 @@ static int nftnl_chain_parse_hook_cb(const struct nlattr *attr, void *data)
 
 static int nftnl_chain_parse_devs(struct nlattr *nest, struct nftnl_chain *c)
 {
-	const char **dev_array;
+	const char **dev_array, **tmp;
 	int len = 0, size = 8;
 	struct nlattr *attr;
 
@@ -618,14 +618,13 @@ static int nftnl_chain_parse_devs(struct nlattr *nest, struct nftnl_chain *c)
 			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;
 		}
 	}
 
-- 
1.8.3.1