From 98c67d187db7808b1f3c95f2110dd4392d034182 Mon Sep 17 00:00:00 2001 From: "Jason A. Donenfeld" Date: Sat, 10 Jun 2017 04:59:12 +0200 Subject: [PATCH] mac80211/wpa: use constant time memory comparison for MACs Otherwise, we enable all sorts of forgeries via timing attack. Signed-off-by: Jason A. Donenfeld Cc: Johannes Berg Cc: linux-wireless@vger.kernel.org Cc: stable@vger.kernel.org Signed-off-by: Johannes Berg --- net/mac80211/wpa.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/net/mac80211/wpa.c b/net/mac80211/wpa.c index c1ef22df865f..cc19614ff4e6 100644 --- a/net/mac80211/wpa.c +++ b/net/mac80211/wpa.c @@ -17,6 +17,7 @@ #include #include #include +#include #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; } -- 2.20.1