Commit 21a6ae9a authored by Jason A. Donenfeld's avatar Jason A. Donenfeld Committed by Ben Hutchings

mac80211/wpa: use constant time memory comparison for MACs

commit 98c67d18 upstream.

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
Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
[bwh: Backported to 3.16: drop changes in
 ieee80211_crypto_aes_{cmac_256,mac}_decrypt()]
Signed-off-by: default avatarBen Hutchings <ben@decadent.org.uk>
parent 8b0fab67
...@@ -16,6 +16,7 @@ ...@@ -16,6 +16,7 @@
#include <asm/unaligned.h> #include <asm/unaligned.h>
#include <net/mac80211.h> #include <net/mac80211.h>
#include <crypto/aes.h> #include <crypto/aes.h>
#include <crypto/algapi.h>
#include "ieee80211_i.h" #include "ieee80211_i.h"
#include "michael.h" #include "michael.h"
...@@ -147,7 +148,7 @@ ieee80211_rx_h_michael_mic_verify(struct ieee80211_rx_data *rx) ...@@ -147,7 +148,7 @@ ieee80211_rx_h_michael_mic_verify(struct ieee80211_rx_data *rx)
data_len = skb->len - hdrlen - MICHAEL_MIC_LEN; data_len = skb->len - hdrlen - MICHAEL_MIC_LEN;
key = &rx->key->conf.key[NL80211_TKIP_DATA_OFFSET_RX_MIC_KEY]; key = &rx->key->conf.key[NL80211_TKIP_DATA_OFFSET_RX_MIC_KEY];
michael_mic(key, hdr, data, data_len, mic); 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; goto mic_fail;
/* remove Michael MIC from payload */ /* remove Michael MIC from payload */
...@@ -768,7 +769,7 @@ ieee80211_crypto_aes_cmac_decrypt(struct ieee80211_rx_data *rx) ...@@ -768,7 +769,7 @@ ieee80211_crypto_aes_cmac_decrypt(struct ieee80211_rx_data *rx)
bip_aad(skb, aad); bip_aad(skb, aad);
ieee80211_aes_cmac(key->u.aes_cmac.tfm, aad, ieee80211_aes_cmac(key->u.aes_cmac.tfm, aad,
skb->data + 24, skb->len - 24, mic); 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++; key->u.aes_cmac.icverrors++;
return RX_DROP_UNUSABLE; return RX_DROP_UNUSABLE;
} }
......
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