[PATCH] ieee80211: Add TKIP crypt->build_iv

This patch adds ieee80211 TKIP build_iv() method to support hardwares
that can do TKIP encryption but relies on ieee80211 layer to build
the IV. It also changes the build_iv() interface to return the key
if possible after the IV is built (this is required by TKIP).

Signed-off-by: Zhu Yi <yi.zhu@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 27 insertions, 26 deletions

diff --git a/net/ieee80211/ieee80211_crypt_tkip.c b/net/ieee80211/ieee80211_crypt_tkip.c
index de56a47edb00..93def94c1b32 100644
--- a/net/ieee80211/ieee80211_crypt_tkip.c
+++ b/net/ieee80211/ieee80211_crypt_tkip.c
@@ -270,34 +270,33 @@ static void tkip_mixing_phase2(u8 * WEPSeed, const u8 * TK, const u16 * TTAK,
 #endif
 }
 
-static u8 *ieee80211_tkip_hdr(struct sk_buff *skb, int hdr_len, void *priv)
+static int ieee80211_tkip_hdr(struct sk_buff *skb, int hdr_len,
+                              u8 * rc4key, int keylen, void *priv)
 {
         struct ieee80211_tkip_data *tkey = priv;
         int len;
-        u8 *rc4key, *pos, *icv;
+        u8 *pos;
         struct ieee80211_hdr_4addr *hdr;
-        u32 crc;
 
         hdr = (struct ieee80211_hdr_4addr *)skb->data;
 
         if (skb_headroom(skb) < 8 || skb->len < hdr_len)
-                return NULL;
+                return -1;
+
+        if (rc4key == NULL || keylen < 16)
+                return -1;
 
         if (!tkey->tx_phase1_done) {
                 tkip_mixing_phase1(tkey->tx_ttak, tkey->key, hdr->addr2,
                                    tkey->tx_iv32);
                 tkey->tx_phase1_done = 1;
         }
-        rc4key = kmalloc(16, GFP_ATOMIC);
-        if (!rc4key)
-                return NULL;
         tkip_mixing_phase2(rc4key, tkey->key, tkey->tx_ttak, tkey->tx_iv16);
 
         len = skb->len - hdr_len;
         pos = skb_push(skb, 8);
         memmove(pos, pos + 8, hdr_len);
         pos += hdr_len;
-        icv = skb_put(skb, 4);
 
         *pos++ = *rc4key;
         *pos++ = *(rc4key + 1);
@@ -308,28 +307,28 @@ static u8 *ieee80211_tkip_hdr(struct sk_buff *skb, int hdr_len, void *priv)
         *pos++ = (tkey->tx_iv32 >> 16) & 0xff;
         *pos++ = (tkey->tx_iv32 >> 24) & 0xff;
 
-        crc = ~crc32_le(~0, pos, len);
-        icv[0] = crc;
-        icv[1] = crc >> 8;
-        icv[2] = crc >> 16;
-        icv[3] = crc >> 24;
+        tkey->tx_iv16++;
+        if (tkey->tx_iv16 == 0) {
+                tkey->tx_phase1_done = 0;
+                tkey->tx_iv32++;
+        }
 
-        return rc4key;
+        return 8;
 }
 
 static int ieee80211_tkip_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
 {
         struct ieee80211_tkip_data *tkey = priv;
         int len;
-        const u8 *rc4key;
-        u8 *pos;
+        u8 rc4key[16], *pos, *icv;
+        u32 crc;
         struct scatterlist sg;
 
         if (tkey->flags & IEEE80211_CRYPTO_TKIP_COUNTERMEASURES) {
                 if (net_ratelimit()) {
                         struct ieee80211_hdr_4addr *hdr =
                             (struct ieee80211_hdr_4addr *)skb->data;
-                        printk(KERN_DEBUG "TKIP countermeasures: dropped "
+                        printk(KERN_DEBUG ": TKIP countermeasures: dropped "
                                "TX packet to " MAC_FMT "\n",
                                MAC_ARG(hdr->addr1));
                 }
@@ -342,22 +341,23 @@ static int ieee80211_tkip_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
         len = skb->len - hdr_len;
         pos = skb->data + hdr_len;
 
-        rc4key = ieee80211_tkip_hdr(skb, hdr_len, priv);
-        if (!rc4key)
+        if ((ieee80211_tkip_hdr(skb, hdr_len, rc4key, 16, priv)) < 0)
                 return -1;
 
+        icv = skb_put(skb, 4);
+
+        crc = ~crc32_le(~0, pos, len);
+        icv[0] = crc;
+        icv[1] = crc >> 8;
+        icv[2] = crc >> 16;
+        icv[3] = crc >> 24;
+
         crypto_cipher_setkey(tkey->tfm_arc4, rc4key, 16);
         sg.page = virt_to_page(pos);
         sg.offset = offset_in_page(pos);
         sg.length = len + 4;
         crypto_cipher_encrypt(tkey->tfm_arc4, &sg, &sg, len + 4);
 
-        tkey->tx_iv16++;
-        if (tkey->tx_iv16 == 0) {
-                tkey->tx_phase1_done = 0;
-                tkey->tx_iv32++;
-        }
-
         return 0;
 }
 
@@ -378,7 +378,7 @@ static int ieee80211_tkip_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
 
         if (tkey->flags & IEEE80211_CRYPTO_TKIP_COUNTERMEASURES) {
                 if (net_ratelimit()) {
-                        printk(KERN_DEBUG "TKIP countermeasures: dropped "
+                        printk(KERN_DEBUG ": TKIP countermeasures: dropped "
                                "received packet from " MAC_FMT "\n",
                                MAC_ARG(hdr->addr2));
                 }
@@ -694,6 +694,7 @@ static struct ieee80211_crypto_ops ieee80211_crypt_tkip = {
         .name = "TKIP",
         .init = ieee80211_tkip_init,
         .deinit = ieee80211_tkip_deinit,
+        .build_iv = ieee80211_tkip_hdr,
         .encrypt_mpdu = ieee80211_tkip_encrypt,
         .decrypt_mpdu = ieee80211_tkip_decrypt,
         .encrypt_msdu = ieee80211_michael_mic_add,