From 75396ae6d433b49482e377e6f8dbf1f42ad53f3a Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Wed, 6 Jul 2011 22:00:35 +0200 Subject: mac80211: fix CMAC races Just like TKIP and CCMP, CMAC has the PN race. It might not actually be possible to hit it now since there aren't multiple ACs for management frames, but fix it anyway. Also move scratch buffers onto the stack. Signed-off-by: Johannes Berg Signed-off-by: John W. Linville --- net/mac80211/wpa.c | 30 +++++++++++++++++------------- 1 file changed, 17 insertions(+), 13 deletions(-) (limited to 'net/mac80211/wpa.c') diff --git a/net/mac80211/wpa.c b/net/mac80211/wpa.c index 7691e4edc74..3452d5e0a3c 100644 --- a/net/mac80211/wpa.c +++ b/net/mac80211/wpa.c @@ -523,6 +523,16 @@ static void bip_aad(struct sk_buff *skb, u8 *aad) } +static inline void bip_ipn_set64(u8 *d, u64 pn) +{ + *d++ = pn; + *d++ = pn >> 8; + *d++ = pn >> 16; + *d++ = pn >> 24; + *d++ = pn >> 32; + *d = pn >> 40; +} + static inline void bip_ipn_swap(u8 *d, const u8 *s) { *d++ = s[5]; @@ -541,8 +551,8 @@ ieee80211_crypto_aes_cmac_encrypt(struct ieee80211_tx_data *tx) struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); struct ieee80211_key *key = tx->key; struct ieee80211_mmie *mmie; - u8 *pn, aad[20]; - int i; + u8 aad[20]; + u64 pn64; if (info->control.hw_key) return 0; @@ -556,22 +566,17 @@ ieee80211_crypto_aes_cmac_encrypt(struct ieee80211_tx_data *tx) mmie->key_id = cpu_to_le16(key->conf.keyidx); /* PN = PN + 1 */ - pn = key->u.aes_cmac.tx_pn; + pn64 = atomic64_inc_return(&key->u.aes_cmac.tx_pn); - for (i = sizeof(key->u.aes_cmac.tx_pn) - 1; i >= 0; i--) { - pn[i]++; - if (pn[i]) - break; - } - bip_ipn_swap(mmie->sequence_number, pn); + bip_ipn_set64(mmie->sequence_number, pn64); bip_aad(skb, aad); /* * MIC = AES-128-CMAC(IGTK, AAD || Management Frame Body || MMIE, 64) */ - ieee80211_aes_cmac(key->u.aes_cmac.tfm, key->u.aes_cmac.tx_crypto_buf, - aad, skb->data + 24, skb->len - 24, mmie->mic); + ieee80211_aes_cmac(key->u.aes_cmac.tfm, aad, + skb->data + 24, skb->len - 24, mmie->mic); return TX_CONTINUE; } @@ -609,8 +614,7 @@ ieee80211_crypto_aes_cmac_decrypt(struct ieee80211_rx_data *rx) if (!(status->flag & RX_FLAG_DECRYPTED)) { /* hardware didn't decrypt/verify MIC */ bip_aad(skb, aad); - ieee80211_aes_cmac(key->u.aes_cmac.tfm, - key->u.aes_cmac.rx_crypto_buf, 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) { key->u.aes_cmac.icverrors++; -- cgit v1.2.3