diff mbox

[v2,3.18-stable] mac80211/wpa: use constant time memory comparison for MACs

Message ID 20170619164406.23738-1-Jason@zx2c4.com (mailing list archive)
State Not Applicable
Delegated to: Johannes Berg
Headers show

Commit Message

Jason A. Donenfeld June 19, 2017, 4:44 p.m. UTC 
Otherwise, we enable all sorts of forgeries via timing attack.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: linux-wireless@vger.kernel.org
Cc: stable@vger.kernel.org
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
This is for 3.18. Tested this, and it works as intended.

 net/mac80211/wpa.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

Comments

Greg KH June 27, 2017, 11:32 a.m. UTC | #1 
On Mon, Jun 19, 2017 at 06:44:06PM +0200, Jason A. Donenfeld wrote:
> Otherwise, we enable all sorts of forgeries via timing attack.
> 
> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
> Cc: Johannes Berg <johannes@sipsolutions.net>
> Cc: linux-wireless@vger.kernel.org
> Cc: stable@vger.kernel.org
> Signed-off-by: Johannes Berg <johannes.berg@intel.com>
> ---
> This is for 3.18. Tested this, and it works as intended.

Thanks, now applied.

greg k-h
diff mbox

Patch

diff --git a/net/mac80211/wpa.c b/net/mac80211/wpa.c
index 983527a4c1ab..bf87de469c03 100644
--- a/net/mac80211/wpa.c
+++ b/net/mac80211/wpa.c
@@ -16,6 +16,7 @@ 
 #include <asm/unaligned.h>
 #include <net/mac80211.h>
 #include <crypto/aes.h>
+#include <crypto/algapi.h>
 
 #include "ieee80211_i.h"
 #include "michael.h"
@@ -150,7 +151,7 @@  ieee80211_rx_h_michael_mic_verify(struct ieee80211_rx_data *rx)
 	data_len = skb->len - hdrlen - MICHAEL_MIC_LEN;
 	key = &rx->key->conf.key[NL80211_TKIP_DATA_OFFSET_RX_MIC_KEY];
 	michael_mic(key, hdr, data, data_len, mic);
-	if (memcmp(mic, data + data_len, MICHAEL_MIC_LEN) != 0)
+	if (crypto_memneq(mic, data + data_len, MICHAEL_MIC_LEN))
 		goto mic_fail;
 
 	/* remove Michael MIC from payload */
@@ -771,7 +772,7 @@  ieee80211_crypto_aes_cmac_decrypt(struct ieee80211_rx_data *rx)
 		bip_aad(skb, aad);
 		ieee80211_aes_cmac(key->u.aes_cmac.tfm, aad,
 				   skb->data + 24, skb->len - 24, mic);
-		if (memcmp(mic, mmie->mic, sizeof(mmie->mic)) != 0) {
+		if (crypto_memneq(mic, mmie->mic, sizeof(mmie->mic))) {
 			key->u.aes_cmac.icverrors++;
 			return RX_DROP_UNUSABLE;
 		}