diff options
| author | Johannes Berg <johannes.berg@intel.com> | 2011-07-06 21:59:39 +0200 |
|---|---|---|
| committer | John W. Linville <linville@tuxdriver.com> | 2011-07-08 11:11:19 -0400 |
| commit | aba83a0b301c32dbb91c017f33307611e1a1d384 (patch) | |
| tree | 9f8478ddf2160c9b4c50666e037e6239ea52e274 /net/mac80211/wpa.c | |
| parent | 523b02ea23b175dd3e46e3daf1bc9354376640a3 (diff) | |
| download | lwn-aba83a0b301c32dbb91c017f33307611e1a1d384.tar.gz lwn-aba83a0b301c32dbb91c017f33307611e1a1d384.zip | |
mac80211: fix CCMP races
Since we can process multiple packets at the
same time for different ACs, but the PN is
allocated from a single counter, we need to
use an atomic value there. Use atomic64_t to
make this cheaper on 64-bit platforms, other
platforms will support this through software
emulation, see lib/atomic64.c.
We also need to use an on-stack scratch buf
so that multiple packets won't corrupt each
others scratch buffers.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Diffstat (limited to 'net/mac80211/wpa.c')
| -rw-r--r-- | net/mac80211/wpa.c | 32 |
1 files changed, 19 insertions, 13 deletions
diff --git a/net/mac80211/wpa.c b/net/mac80211/wpa.c index 4ded2ae48a5f..7691e4edc74a 100644 --- a/net/mac80211/wpa.c +++ b/net/mac80211/wpa.c @@ -15,6 +15,7 @@ #include <linux/gfp.h> #include <asm/unaligned.h> #include <net/mac80211.h> +#include <crypto/aes.h> #include "ieee80211_i.h" #include "michael.h" @@ -290,6 +291,8 @@ static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *scratch, unsigned int hdrlen; struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data; + memset(scratch, 0, 6 * AES_BLOCK_LEN); + b_0 = scratch + 3 * AES_BLOCK_LEN; aad = scratch + 4 * AES_BLOCK_LEN; @@ -380,8 +383,10 @@ static int ccmp_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb) struct ieee80211_key *key = tx->key; struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); int hdrlen, len, tail; - u8 *pos, *pn; - int i; + u8 *pos; + u8 pn[6]; + u64 pn64; + u8 scratch[6 * AES_BLOCK_LEN]; if (info->control.hw_key && !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV)) { @@ -409,14 +414,14 @@ static int ccmp_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb) hdr = (struct ieee80211_hdr *) pos; pos += hdrlen; - /* PN = PN + 1 */ - pn = key->u.ccmp.tx_pn; + pn64 = atomic64_inc_return(&key->u.ccmp.tx_pn); - for (i = CCMP_PN_LEN - 1; i >= 0; i--) { - pn[i]++; - if (pn[i]) - break; - } + pn[5] = pn64; + pn[4] = pn64 >> 8; + pn[3] = pn64 >> 16; + pn[2] = pn64 >> 24; + pn[1] = pn64 >> 32; + pn[0] = pn64 >> 40; ccmp_pn2hdr(pos, pn, key->conf.keyidx); @@ -425,8 +430,8 @@ static int ccmp_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb) return 0; pos += CCMP_HDR_LEN; - ccmp_special_blocks(skb, pn, key->u.ccmp.tx_crypto_buf, 0); - ieee80211_aes_ccm_encrypt(key->u.ccmp.tfm, key->u.ccmp.tx_crypto_buf, pos, len, + ccmp_special_blocks(skb, pn, scratch, 0); + ieee80211_aes_ccm_encrypt(key->u.ccmp.tfm, scratch, pos, len, pos, skb_put(skb, CCMP_MIC_LEN)); return 0; @@ -482,11 +487,12 @@ ieee80211_crypto_ccmp_decrypt(struct ieee80211_rx_data *rx) } if (!(status->flag & RX_FLAG_DECRYPTED)) { + u8 scratch[6 * AES_BLOCK_LEN]; /* hardware didn't decrypt/verify MIC */ - ccmp_special_blocks(skb, pn, key->u.ccmp.rx_crypto_buf, 1); + ccmp_special_blocks(skb, pn, scratch, 1); if (ieee80211_aes_ccm_decrypt( - key->u.ccmp.tfm, key->u.ccmp.rx_crypto_buf, + key->u.ccmp.tfm, scratch, skb->data + hdrlen + CCMP_HDR_LEN, data_len, skb->data + skb->len - CCMP_MIC_LEN, skb->data + hdrlen + CCMP_HDR_LEN)) |