From: Jason A. Donenfeld <Jason@zx2c4.com>
Date: Tue, 17 Oct 2017 18:32:07 +0000 (+0200)
Subject: mac80211: use constant time comparison with keys
X-Git-Tag: v3.18.82~18
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=32025b5c58605cdc0552d7976d010f10fa13f28a;p=thirdparty%2Fkernel%2Fstable.git

mac80211: use constant time comparison with keys

commit 2bdd713b92a9cade239d3c7d15205a09f556624d upstream.

Otherwise we risk leaking information via timing side channel.

Fixes: fdf7cb4185b6 ("mac80211: accept key reinstall without changing anything")
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Cc: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/net/mac80211/key.c b/net/mac80211/key.c
index 8f794436b0289..54dfbaac8be65 100644
--- a/net/mac80211/key.c
+++ b/net/mac80211/key.c
@@ -19,6 +19,7 @@
 #include <linux/slab.h>
 #include <linux/export.h>
 #include <net/mac80211.h>
+#include <crypto/algapi.h>
 #include <asm/unaligned.h>
 #include "ieee80211_i.h"
 #include "driver-ops.h"
@@ -501,7 +502,7 @@ int ieee80211_key_link(struct ieee80211_key *key,
 	 * new version of the key to avoid nonce reuse or replay issues.
 	 */
 	if (old_key && key->conf.keylen == old_key->conf.keylen &&
-	    !memcmp(key->conf.key, old_key->conf.key, key->conf.keylen)) {
+	    !crypto_memneq(key->conf.key, old_key->conf.key, key->conf.keylen)) {
 		ieee80211_key_free_unused(key);
 		ret = 0;
 		goto out;