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Commit 98c67d18 authored by Jason A. Donenfeld's avatar Jason A. Donenfeld Committed by Johannes Berg
Browse files

mac80211/wpa: use constant time memory comparison for MACs 



Otherwise, we enable all sorts of forgeries via timing attack.

Signed-off-by: default avatarJason 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: default avatarJohannes Berg <johannes.berg@intel.com>
parent c87905be

net/mac80211/wpa.c

+5 −4
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 
#include <asm/unaligned.h>

#include <net/mac80211.h>

#include <crypto/aes.h>

#include <crypto/algapi.h>



#include "ieee80211_i.h"

#include "michael.h"
@@ -153,7 +154,7 @@ 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 */
@@ -1048,7 +1049,7 @@ 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;

		}
@@ -1098,7 +1099,7 @@ ieee80211_crypto_aes_cmac_256_decrypt(struct ieee80211_rx_data *rx) 
		bip_aad(skb, aad);

		ieee80211_aes_cmac_256(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;

		}
@@ -1202,7 +1203,7 @@ ieee80211_crypto_aes_gmac_decrypt(struct ieee80211_rx_data *rx) 
		if (ieee80211_aes_gmac(key->u.aes_gmac.tfm, aad, nonce,

				       skb->data + 24, skb->len - 24,

				       mic) < 0 ||

		    memcmp(mic, mmie->mic, sizeof(mmie->mic)) != 0) {

		    crypto_memneq(mic, mmie->mic, sizeof(mmie->mic))) {

			key->u.aes_gmac.icverrors++;

			return RX_DROP_UNUSABLE;

		}