mac80211: Let drivers have access to TKIP key offets for TX and RX MIC

Some drivers may want to to use the TKIP key offsets for TX and RX
MIC so lets move this out. Lets also clear up a bit how this is used
internally in mac80211.

Signed-off-by: Luis R. Rodriguez <[email protected]>
Signed-off-by: John W. Linville <[email protected]>

Author: Luis R. Rodriguez

include/linux/nl80211.h

@@ -241,7 +241,10 @@ enum nl80211_attrs {
 	NL80211_ATTR_MAX = __NL80211_ATTR_AFTER_LAST - 1
 };
 
-#define NL80211_MAX_SUPP_RATES	32
+#define NL80211_MAX_SUPP_RATES			32
+#define NL80211_TKIP_DATA_OFFSET_ENCR_KEY	0
+#define NL80211_TKIP_DATA_OFFSET_TX_MIC_KEY	16
+#define NL80211_TKIP_DATA_OFFSET_RX_MIC_KEY	24
 
 /**
  * enum nl80211_iftype - (virtual) interface types

include/net/mac80211.h

@@ -595,7 +595,12 @@ enum ieee80211_key_flags {
  * @flags: key flags, see &enum ieee80211_key_flags.
  * @keyidx: the key index (0-3)
  * @keylen: key material length
- * @key: key material
+ * @key: key material. For ALG_TKIP the key is encoded as a 256-bit (32 byte)
+ * 	data block:
+ * 	- Temporal Encryption Key (128 bits)
+ * 	- Temporal Authenticator Tx MIC Key (64 bits)
+ * 	- Temporal Authenticator Rx MIC Key (64 bits)
+ *
  */
 struct ieee80211_key_conf {
 	enum ieee80211_key_alg alg;

net/mac80211/key.h

@@ -16,31 +16,18 @@
 #include <linux/rcupdate.h>
 #include <net/mac80211.h>
 
-/* ALG_TKIP
- * struct ieee80211_key::key is encoded as a 256-bit (32 byte) data block:
- * Temporal Encryption Key (128 bits)
- * Temporal Authenticator Tx MIC Key (64 bits)
- * Temporal Authenticator Rx MIC Key (64 bits)
- */
-
-#define WEP_IV_LEN 4
-#define WEP_ICV_LEN 4
-
-#define ALG_TKIP_KEY_LEN 32
-/* Starting offsets for each key */
-#define ALG_TKIP_TEMP_ENCR_KEY 0
-#define ALG_TKIP_TEMP_AUTH_TX_MIC_KEY 16
-#define ALG_TKIP_TEMP_AUTH_RX_MIC_KEY 24
-#define TKIP_IV_LEN 8
-#define TKIP_ICV_LEN 4
-
-#define ALG_CCMP_KEY_LEN 16
-#define CCMP_HDR_LEN 8
-#define CCMP_MIC_LEN 8
-#define CCMP_TK_LEN 16
-#define CCMP_PN_LEN 6
-
-#define NUM_RX_DATA_QUEUES 17
+#define WEP_IV_LEN		4
+#define WEP_ICV_LEN		4
+#define ALG_TKIP_KEY_LEN	32
+#define ALG_CCMP_KEY_LEN	16
+#define CCMP_HDR_LEN		8
+#define CCMP_MIC_LEN		8
+#define CCMP_TK_LEN		16
+#define CCMP_PN_LEN		6
+#define TKIP_IV_LEN		8
+#define TKIP_ICV_LEN		4
+
+#define NUM_RX_DATA_QUEUES	17
 
 struct ieee80211_local;
 struct ieee80211_sub_if_data;

net/mac80211/tkip.c

@@ -164,7 +164,7 @@ void ieee80211_get_tkip_key(struct ieee80211_key_conf *keyconf,
 	iv16 = data[2] | (data[0] << 8);
 	iv32 = get_unaligned_le32(&data[4]);
 
-	tk = &key->conf.key[ALG_TKIP_TEMP_ENCR_KEY];
+	tk = &key->conf.key[NL80211_TKIP_DATA_OFFSET_ENCR_KEY];
 	ctx = &key->u.tkip.tx;
 
 #ifdef CONFIG_MAC80211_TKIP_DEBUG
@@ -205,7 +205,7 @@ void ieee80211_tkip_encrypt_data(struct crypto_blkcipher *tfm,
 {
 	u8 rc4key[16];
 	struct tkip_ctx *ctx = &key->u.tkip.tx;
-	const u8 *tk = &key->conf.key[ALG_TKIP_TEMP_ENCR_KEY];
+	const u8 *tk = &key->conf.key[NL80211_TKIP_DATA_OFFSET_ENCR_KEY];
 
 	/* Calculate per-packet key */
 	if (ctx->iv16 == 0 || !ctx->initialized)
@@ -231,7 +231,7 @@ int ieee80211_tkip_decrypt_data(struct crypto_blkcipher *tfm,
 	u32 iv16;
 	u8 rc4key[16], keyid, *pos = payload;
 	int res;
-	const u8 *tk = &key->conf.key[ALG_TKIP_TEMP_ENCR_KEY];
+	const u8 *tk = &key->conf.key[NL80211_TKIP_DATA_OFFSET_ENCR_KEY];
 
 	if (payload_len < 12)
 		return -1;
@@ -286,13 +286,13 @@ int ieee80211_tkip_decrypt_data(struct crypto_blkcipher *tfm,
 #ifdef CONFIG_MAC80211_TKIP_DEBUG
 		{
 			int i;
+			u8 key_offset = NL80211_TKIP_DATA_OFFSET_ENCR_KEY;
 			DECLARE_MAC_BUF(mac);
 			printk(KERN_DEBUG "TKIP decrypt: Phase1 TA=%s"
 			       " TK=", print_mac(mac, ta));
 			for (i = 0; i < 16; i++)
 				printk("%02x ",
-				       key->conf.key[
-						ALG_TKIP_TEMP_ENCR_KEY + i]);
+				       key->conf.key[key_offset + i]);
 			printk("\n");
 			printk(KERN_DEBUG "TKIP decrypt: P1K=");
 			for (i = 0; i < 5; i++)

net/mac80211/wpa.c

@@ -49,7 +49,7 @@ static int ieee80211_get_hdr_info(const struct sk_buff *skb, u8 **sa, u8 **da,
 ieee80211_tx_result
 ieee80211_tx_h_michael_mic_add(struct ieee80211_tx_data *tx)
 {
-	u8 *data, *sa, *da, *key, *mic, qos_tid;
+	u8 *data, *sa, *da, *key, *mic, qos_tid, key_offset;
 	size_t data_len;
 	u16 fc;
 	struct sk_buff *skb = tx->skb;
@@ -88,8 +88,12 @@ ieee80211_tx_h_michael_mic_add(struct ieee80211_tx_data *tx)
 #else
 	authenticator = 1;
 #endif
-	key = &tx->key->conf.key[authenticator ? ALG_TKIP_TEMP_AUTH_TX_MIC_KEY :
-				 ALG_TKIP_TEMP_AUTH_RX_MIC_KEY];
+	/* At this point we know we're using ALG_TKIP. To get the MIC key
+	 * we now will rely on the offset from the ieee80211_key_conf::key */
+	key_offset = authenticator ?
+		NL80211_TKIP_DATA_OFFSET_TX_MIC_KEY :
+		NL80211_TKIP_DATA_OFFSET_RX_MIC_KEY;
+	key = &tx->key->conf.key[key_offset];
 	mic = skb_put(skb, MICHAEL_MIC_LEN);
 	michael_mic(key, da, sa, qos_tid & 0x0f, data, data_len, mic);
 
@@ -100,7 +104,7 @@ ieee80211_tx_h_michael_mic_add(struct ieee80211_tx_data *tx)
 ieee80211_rx_result
 ieee80211_rx_h_michael_mic_verify(struct ieee80211_rx_data *rx)
 {
-	u8 *data, *sa, *da, *key = NULL, qos_tid;
+	u8 *data, *sa, *da, *key = NULL, qos_tid, key_offset;
 	size_t data_len;
 	u16 fc;
 	u8 mic[MICHAEL_MIC_LEN];
@@ -131,8 +135,12 @@ ieee80211_rx_h_michael_mic_verify(struct ieee80211_rx_data *rx)
 #else
 	authenticator = 1;
 #endif
-	key = &rx->key->conf.key[authenticator ? ALG_TKIP_TEMP_AUTH_RX_MIC_KEY :
-				 ALG_TKIP_TEMP_AUTH_TX_MIC_KEY];
+	/* At this point we know we're using ALG_TKIP. To get the MIC key
+	 * we now will rely on the offset from the ieee80211_key_conf::key */
+	key_offset = authenticator ?
+		NL80211_TKIP_DATA_OFFSET_RX_MIC_KEY :
+		NL80211_TKIP_DATA_OFFSET_TX_MIC_KEY;
+	key = &rx->key->conf.key[key_offset];
 	michael_mic(key, da, sa, qos_tid & 0x0f, data, data_len, mic);
 	if (memcmp(mic, data + data_len, MICHAEL_MIC_LEN) != 0 || wpa_test) {
 		if (!(rx->flags & IEEE80211_RX_RA_MATCH))