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Commit 5d2cdcd4 authored by Emmanuel Grumbach's avatar Emmanuel Grumbach Committed by John W. Linville
Browse files

mac80211: get a TKIP phase key from skb 



This patch makes mac80211 able to compute a TKIP key from an skb.
The requested key can be a phase 1 or a phase 2 key.
This is useful for drivers who need to provide tkip key to their
HW to enable HW encryption.

Signed-off-by: default avatarEmmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: default avatarTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent 17e476b8

include/net/mac80211.h

+30 −0
Original line number Original line Diff line number Diff line
@@ -643,6 +643,21 @@ enum sta_notify_cmd { 
	STA_NOTIFY_ADD, STA_NOTIFY_REMOVE

	STA_NOTIFY_ADD, STA_NOTIFY_REMOVE

};

};





/**

 * enum ieee80211_tkip_key_type - get tkip key

 *

 * Used by drivers which need to get a tkip key for skb. Some drivers need a

 * phase 1 key, others need a phase 2 key. A single function allows the driver

 * to get the key, this enum indicates what type of key is required.

 *

 * @IEEE80211_TKIP_P1_KEY: the driver needs a phase 1 key

 * @IEEE80211_TKIP_P2_KEY: the driver needs a phase 2 key

 */

enum ieee80211_tkip_key_type {

	IEEE80211_TKIP_P1_KEY,

	IEEE80211_TKIP_P2_KEY,

};



/**

/**

 * enum ieee80211_hw_flags - hardware flags

 * enum ieee80211_hw_flags - hardware flags

 *

 *
@@ -1471,6 +1486,21 @@ int ieee80211_get_hdrlen_from_skb(const struct sk_buff *skb); 
 */

 */

int ieee80211_get_hdrlen(u16 fc);

int ieee80211_get_hdrlen(u16 fc);





/**

 * ieee80211_get_tkip_key - get a TKIP rc4 for skb

 *

 * This function computes a TKIP rc4 key for an skb. It computes

 * a phase 1 key if needed (iv16 wraps around). This function is to

 * be used by drivers which can do HW encryption but need to compute

 * to phase 1/2 key in SW.

 *

 * @keyconf: the parameter passed with the set key

 * @skb: the skb for which the key is needed

 * @rc4key: a buffer to which the key will be written

 */

void ieee80211_get_tkip_key(struct ieee80211_key_conf *keyconf,

				struct sk_buff *skb,

				enum ieee80211_tkip_key_type type, u8 *key);

/**

/**

 * ieee80211_wake_queue - wake specific queue

 * ieee80211_wake_queue - wake specific queue

 * @hw: pointer as obtained from ieee80211_alloc_hw().

 * @hw: pointer as obtained from ieee80211_alloc_hw().

net/mac80211/tkip.c

+53 −0
Original line number Original line Diff line number Diff line
@@ -214,6 +214,59 @@ void ieee80211_tkip_gen_rc4key(struct ieee80211_key *key, u8 *ta, 
			   key->u.tkip.iv16, rc4key);

			   key->u.tkip.iv16, rc4key);

}

}





void ieee80211_get_tkip_key(struct ieee80211_key_conf *keyconf,

			struct sk_buff *skb, enum ieee80211_tkip_key_type type,

			u8 *outkey)

{

	struct ieee80211_key *key = (struct ieee80211_key *)

			container_of(keyconf, struct ieee80211_key, conf);

	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;

	u8 *data = (u8 *) hdr;

	u16 fc = le16_to_cpu(hdr->frame_control);

	int hdr_len = ieee80211_get_hdrlen(fc);

	u8 *ta = hdr->addr2;

	u16 iv16;

	u32 iv32;



	iv16 = data[hdr_len] << 8;

	iv16 += data[hdr_len + 2];

	iv32 = data[hdr_len + 4] +

		(data[hdr_len + 5] >> 8) +

		(data[hdr_len + 6] >> 16) +

		(data[hdr_len + 7] >> 24);



#ifdef CONFIG_TKIP_DEBUG

	printk(KERN_DEBUG "TKIP encrypt: iv16 = 0x%04x, iv32 = 0x%08x\n",

			iv16, iv32);



	if (iv32 != key->u.tkip.iv32) {

		printk(KERN_DEBUG "skb: iv32 = 0x%08x key: iv32 = 0x%08x\n",

			iv32, key->u.tkip.iv32);

		printk(KERN_DEBUG "Wrap around of iv16 in the middle of a "

			"fragmented packet\n");

	}

#endif /* CONFIG_TKIP_DEBUG */



	/* Update the p1k only when the iv16 in the packet wraps around, this

	 * might occur after the wrap around of iv16 in the key in case of

	 * fragmented packets. */

	if (iv16 == 0 || !key->u.tkip.tx_initialized) {

		/* IV16 wrapped around - perform TKIP phase 1 */

		tkip_mixing_phase1(ta, &key->conf.key[ALG_TKIP_TEMP_ENCR_KEY],

			iv32, key->u.tkip.p1k);

		key->u.tkip.tx_initialized = 1;

	}



	if (type == IEEE80211_TKIP_P1_KEY) {

		memcpy(outkey, key->u.tkip.p1k, sizeof(u16) * 5);

		return;

	}



	tkip_mixing_phase2(key->u.tkip.p1k,

		&key->conf.key[ALG_TKIP_TEMP_ENCR_KEY],	iv16, outkey);

}

EXPORT_SYMBOL(ieee80211_get_tkip_key);



/* Encrypt packet payload with TKIP using @key. @pos is a pointer to the

/* Encrypt packet payload with TKIP using @key. @pos is a pointer to the

 * beginning of the buffer containing payload. This payload must include

 * beginning of the buffer containing payload. This payload must include

 * headroom of eight octets for IV and Ext. IV and taildroom of four octets

 * headroom of eight octets for IV and Ext. IV and taildroom of four octets