net/mac80211/wep.c - pub/scm/linux/kernel/git/hpa/linux-2.6-klibc - Git at Google

 /*
  * Software WEP encryption implementation
  * Copyright 2002, Jouni Malinen <jkmaline@cc.hut.fi>
  * Copyright 2003, Instant802 Networks, Inc.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  */

 #include <linux/netdevice.h>
 #include <linux/types.h>
 #include <linux/random.h>
 #include <linux/compiler.h>
 #include <linux/crc32.h>
 #include <linux/crypto.h>
 #include <linux/err.h>
 #include <linux/mm.h>
 #include <asm/scatterlist.h>

 #include <net/mac80211.h>
 #include "ieee80211_i.h"
 #include "wep.h"


 int ieee80211_wep_init(struct ieee80211_local *local)
 {
 	/* start WEP IV from a random value */
 	get_random_bytes(&local->wep_iv, WEP_IV_LEN);

 	local->wep_tx_tfm = crypto_alloc_blkcipher("ecb(arc4)", 0,
 						CRYPTO_ALG_ASYNC);
 	if (IS_ERR(local->wep_tx_tfm))
 		return -ENOMEM;

 	local->wep_rx_tfm = crypto_alloc_blkcipher("ecb(arc4)", 0,
 						CRYPTO_ALG_ASYNC);
 	if (IS_ERR(local->wep_rx_tfm)) {
 		crypto_free_blkcipher(local->wep_tx_tfm);
 		return -ENOMEM;
 	}

 	return 0;
 }

 void ieee80211_wep_free(struct ieee80211_local *local)
 {
 	crypto_free_blkcipher(local->wep_tx_tfm);
 	crypto_free_blkcipher(local->wep_rx_tfm);
 }

 static inline int ieee80211_wep_weak_iv(u32 iv, int keylen)
 {
 	/* Fluhrer, Mantin, and Shamir have reported weaknesses in the
 	 * key scheduling algorithm of RC4. At least IVs (KeyByte + 3,
 	 * 0xff, N) can be used to speedup attacks, so avoid using them. */
 	if ((iv & 0xff00) == 0xff00) {
 		u8 B = (iv >> 16) & 0xff;
 		if (B >= 3 && B < 3 + keylen)
 			return 1;
 	}
 	return 0;
 }


 void ieee80211_wep_get_iv(struct ieee80211_local *local,
 			  struct ieee80211_key *key, u8 *iv)
 {
 	local->wep_iv++;
 	if (ieee80211_wep_weak_iv(local->wep_iv, key->keylen))
 		local->wep_iv += 0x0100;

 	if (!iv)
 		return;

 	*iv++ = (local->wep_iv >> 16) & 0xff;
 	*iv++ = (local->wep_iv >> 8) & 0xff;
 	*iv++ = local->wep_iv & 0xff;
 	*iv++ = key->keyidx << 6;
 }


 u8 * ieee80211_wep_add_iv(struct ieee80211_local *local,
 			  struct sk_buff *skb,
 			  struct ieee80211_key *key)
 {
 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 	u16 fc;
 	int hdrlen;
 	u8 *newhdr;

 	fc = le16_to_cpu(hdr->frame_control);
 	fc |= IEEE80211_FCTL_PROTECTED;
 	hdr->frame_control = cpu_to_le16(fc);

 	if ((skb_headroom(skb) < WEP_IV_LEN ||
 	     skb_tailroom(skb) < WEP_ICV_LEN)) {
 		I802_DEBUG_INC(local->tx_expand_skb_head);
 		if (unlikely(pskb_expand_head(skb, WEP_IV_LEN, WEP_ICV_LEN,
 					      GFP_ATOMIC)))
 			return NULL;
 	}

 	hdrlen = ieee80211_get_hdrlen(fc);
 	newhdr = skb_push(skb, WEP_IV_LEN);
 	memmove(newhdr, newhdr + WEP_IV_LEN, hdrlen);
 	ieee80211_wep_get_iv(local, key, newhdr + hdrlen);
 	return newhdr + hdrlen;
 }


 void ieee80211_wep_remove_iv(struct ieee80211_local *local,
 			     struct sk_buff *skb,
 			     struct ieee80211_key *key)
 {
 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 	u16 fc;
 	int hdrlen;

 	fc = le16_to_cpu(hdr->frame_control);
 	hdrlen = ieee80211_get_hdrlen(fc);
 	memmove(skb->data + WEP_IV_LEN, skb->data, hdrlen);
 	skb_pull(skb, WEP_IV_LEN);
 }


 /* Perform WEP encryption using given key. data buffer must have tailroom
  * for 4-byte ICV. data_len must not include this ICV. Note: this function
  * does _not_ add IV. data = RC4(data | CRC32(data)) */
 void ieee80211_wep_encrypt_data(struct crypto_blkcipher *tfm, u8 *rc4key,
 				size_t klen, u8 *data, size_t data_len)
 {
 	struct blkcipher_desc desc = { .tfm = tfm };
 	struct scatterlist sg;
 	__le32 *icv;

 	icv = (__le32 *)(data + data_len);
 	*icv = cpu_to_le32(~crc32_le(~0, data, data_len));

 	crypto_blkcipher_setkey(tfm, rc4key, klen);
 	sg.page = virt_to_page(data);
 	sg.offset = offset_in_page(data);
 	sg.length = data_len + WEP_ICV_LEN;
 	crypto_blkcipher_encrypt(&desc, &sg, &sg, sg.length);
 }


 /* Perform WEP encryption on given skb. 4 bytes of extra space (IV) in the
  * beginning of the buffer 4 bytes of extra space (ICV) in the end of the
  * buffer will be added. Both IV and ICV will be transmitted, so the
  * payload length increases with 8 bytes.
  *
  * WEP frame payload: IV + TX key idx, RC4(data), ICV = RC4(CRC32(data))
  */
 int ieee80211_wep_encrypt(struct ieee80211_local *local, struct sk_buff *skb,
 			  struct ieee80211_key *key)
 {
 	u32 klen;
 	u8 *rc4key, *iv;
 	size_t len;

 	if (!key || key->alg != ALG_WEP)
 		return -1;

 	klen = 3 + key->keylen;
 	rc4key = kmalloc(klen, GFP_ATOMIC);
 	if (!rc4key)
 		return -1;

 	iv = ieee80211_wep_add_iv(local, skb, key);
 	if (!iv) {
 		kfree(rc4key);
 		return -1;
 	}

 	len = skb->len - (iv + WEP_IV_LEN - skb->data);

 	/* Prepend 24-bit IV to RC4 key */
 	memcpy(rc4key, iv, 3);

 	/* Copy rest of the WEP key (the secret part) */
 	memcpy(rc4key + 3, key->key, key->keylen);

 	/* Add room for ICV */
 	skb_put(skb, WEP_ICV_LEN);

 	ieee80211_wep_encrypt_data(local->wep_tx_tfm, rc4key, klen,
 				   iv + WEP_IV_LEN, len);

 	kfree(rc4key);

 	return 0;
 }


 /* Perform WEP decryption using given key. data buffer includes encrypted
  * payload, including 4-byte ICV, but _not_ IV. data_len must not include ICV.
  * Return 0 on success and -1 on ICV mismatch. */
 int ieee80211_wep_decrypt_data(struct crypto_blkcipher *tfm, u8 *rc4key,
 			       size_t klen, u8 *data, size_t data_len)
 {
 	struct blkcipher_desc desc = { .tfm = tfm };
 	struct scatterlist sg;
 	__le32 crc;

 	crypto_blkcipher_setkey(tfm, rc4key, klen);
 	sg.page = virt_to_page(data);
 	sg.offset = offset_in_page(data);
 	sg.length = data_len + WEP_ICV_LEN;
 	crypto_blkcipher_decrypt(&desc, &sg, &sg, sg.length);

 	crc = cpu_to_le32(~crc32_le(~0, data, data_len));
 	if (memcmp(&crc, data + data_len, WEP_ICV_LEN) != 0)
 		/* ICV mismatch */
 		return -1;

 	return 0;
 }


 /* Perform WEP decryption on given skb. Buffer includes whole WEP part of
  * the frame: IV (4 bytes), encrypted payload (including SNAP header),
  * ICV (4 bytes). skb->len includes both IV and ICV.
  *
  * Returns 0 if frame was decrypted successfully and ICV was correct and -1 on
  * failure. If frame is OK, IV and ICV will be removed, i.e., decrypted payload
  * is moved to the beginning of the skb and skb length will be reduced.
  */
 int ieee80211_wep_decrypt(struct ieee80211_local *local, struct sk_buff *skb,
 			  struct ieee80211_key *key)
 {
 	u32 klen;
 	u8 *rc4key;
 	u8 keyidx;
 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 	u16 fc;
 	int hdrlen;
 	size_t len;
 	int ret = 0;

 	fc = le16_to_cpu(hdr->frame_control);
 	if (!(fc & IEEE80211_FCTL_PROTECTED))
 		return -1;

 	hdrlen = ieee80211_get_hdrlen(fc);

 	if (skb->len < 8 + hdrlen)
 		return -1;

 	len = skb->len - hdrlen - 8;

 	keyidx = skb->data[hdrlen + 3] >> 6;

 	if (!key || keyidx != key->keyidx || key->alg != ALG_WEP)
 		return -1;

 	klen = 3 + key->keylen;

 	rc4key = kmalloc(klen, GFP_ATOMIC);
 	if (!rc4key)
 		return -1;

 	/* Prepend 24-bit IV to RC4 key */
 	memcpy(rc4key, skb->data + hdrlen, 3);

 	/* Copy rest of the WEP key (the secret part) */
 	memcpy(rc4key + 3, key->key, key->keylen);

 	if (ieee80211_wep_decrypt_data(local->wep_rx_tfm, rc4key, klen,
 				       skb->data + hdrlen + WEP_IV_LEN,
 				       len)) {
 		printk(KERN_DEBUG "WEP decrypt failed (ICV)\n");
 		ret = -1;
 	}

 	kfree(rc4key);

 	/* Trim ICV */
 	skb_trim(skb, skb->len - WEP_ICV_LEN);

 	/* Remove IV */
 	memmove(skb->data + WEP_IV_LEN, skb->data, hdrlen);
 	skb_pull(skb, WEP_IV_LEN);

 	return ret;
 }


 int ieee80211_wep_get_keyidx(struct sk_buff *skb)
 {
 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 	u16 fc;
 	int hdrlen;

 	fc = le16_to_cpu(hdr->frame_control);
 	if (!(fc & IEEE80211_FCTL_PROTECTED))
 		return -1;

 	hdrlen = ieee80211_get_hdrlen(fc);

 	if (skb->len < 8 + hdrlen)
 		return -1;

 	return skb->data[hdrlen + 3] >> 6;
 }


 u8 * ieee80211_wep_is_weak_iv(struct sk_buff *skb, struct ieee80211_key *key)
 {
 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 	u16 fc;
 	int hdrlen;
 	u8 *ivpos;
 	u32 iv;

 	fc = le16_to_cpu(hdr->frame_control);
 	if (!(fc & IEEE80211_FCTL_PROTECTED))
 		return NULL;

 	hdrlen = ieee80211_get_hdrlen(fc);
 	ivpos = skb->data + hdrlen;
 	iv = (ivpos[0] << 16) | (ivpos[1] << 8) | ivpos[2];

 	if (ieee80211_wep_weak_iv(iv, key->keylen))
 		return ivpos;

 	return NULL;
 }
	/*
	* Software WEP encryption implementation
	* Copyright 2002, Jouni Malinen <jkmaline@cc.hut.fi>
	* Copyright 2003, Instant802 Networks, Inc.
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 as
	* published by the Free Software Foundation.
	*/

	#include <linux/netdevice.h>
	#include <linux/types.h>
	#include <linux/random.h>
	#include <linux/compiler.h>
	#include <linux/crc32.h>
	#include <linux/crypto.h>
	#include <linux/err.h>
	#include <linux/mm.h>
	#include <asm/scatterlist.h>

	#include <net/mac80211.h>
	#include "ieee80211_i.h"
	#include "wep.h"


	int ieee80211_wep_init(struct ieee80211_local *local)
	{
	/* start WEP IV from a random value */
	get_random_bytes(&local->wep_iv, WEP_IV_LEN);

	local->wep_tx_tfm = crypto_alloc_blkcipher("ecb(arc4)", 0,
	CRYPTO_ALG_ASYNC);
	if (IS_ERR(local->wep_tx_tfm))
	return -ENOMEM;

	local->wep_rx_tfm = crypto_alloc_blkcipher("ecb(arc4)", 0,
	CRYPTO_ALG_ASYNC);
	if (IS_ERR(local->wep_rx_tfm)) {
	crypto_free_blkcipher(local->wep_tx_tfm);
	return -ENOMEM;
	}

	return 0;
	}

	void ieee80211_wep_free(struct ieee80211_local *local)
	{
	crypto_free_blkcipher(local->wep_tx_tfm);
	crypto_free_blkcipher(local->wep_rx_tfm);
	}

	static inline int ieee80211_wep_weak_iv(u32 iv, int keylen)
	{
	/* Fluhrer, Mantin, and Shamir have reported weaknesses in the
	* key scheduling algorithm of RC4. At least IVs (KeyByte + 3,
	* 0xff, N) can be used to speedup attacks, so avoid using them. */
	if ((iv & 0xff00) == 0xff00) {
	u8 B = (iv >> 16) & 0xff;
	if (B >= 3 && B < 3 + keylen)
	return 1;
	}
	return 0;
	}


	void ieee80211_wep_get_iv(struct ieee80211_local *local,
	struct ieee80211_key key, u8 iv)
	{
	local->wep_iv++;
	if (ieee80211_wep_weak_iv(local->wep_iv, key->keylen))
	local->wep_iv += 0x0100;

	if (!iv)
	return;

	*iv++ = (local->wep_iv >> 16) & 0xff;
	*iv++ = (local->wep_iv >> 8) & 0xff;
	*iv++ = local->wep_iv & 0xff;
	*iv++ = key->keyidx << 6;
	}


	u8 * ieee80211_wep_add_iv(struct ieee80211_local *local,
	struct sk_buff *skb,
	struct ieee80211_key *key)
	{
	struct ieee80211_hdr hdr = (struct ieee80211_hdr ) skb->data;
	u16 fc;
	int hdrlen;
	u8 *newhdr;

	fc = le16_to_cpu(hdr->frame_control);
	fc \|= IEEE80211_FCTL_PROTECTED;
	hdr->frame_control = cpu_to_le16(fc);

	if ((skb_headroom(skb) < WEP_IV_LEN \|\|
	skb_tailroom(skb) < WEP_ICV_LEN)) {
	I802_DEBUG_INC(local->tx_expand_skb_head);
	if (unlikely(pskb_expand_head(skb, WEP_IV_LEN, WEP_ICV_LEN,
	GFP_ATOMIC)))
	return NULL;
	}

	hdrlen = ieee80211_get_hdrlen(fc);
	newhdr = skb_push(skb, WEP_IV_LEN);
	memmove(newhdr, newhdr + WEP_IV_LEN, hdrlen);
	ieee80211_wep_get_iv(local, key, newhdr + hdrlen);
	return newhdr + hdrlen;
	}


	void ieee80211_wep_remove_iv(struct ieee80211_local *local,
	struct sk_buff *skb,
	struct ieee80211_key *key)
	{
	struct ieee80211_hdr hdr = (struct ieee80211_hdr ) skb->data;
	u16 fc;
	int hdrlen;

	fc = le16_to_cpu(hdr->frame_control);
	hdrlen = ieee80211_get_hdrlen(fc);
	memmove(skb->data + WEP_IV_LEN, skb->data, hdrlen);
	skb_pull(skb, WEP_IV_LEN);
	}


	/* Perform WEP encryption using given key. data buffer must have tailroom
	* for 4-byte ICV. data_len must not include this ICV. Note: this function
	* does _not_ add IV. data = RC4(data \| CRC32(data)) */
	void ieee80211_wep_encrypt_data(struct crypto_blkcipher tfm, u8 rc4key,
	size_t klen, u8 *data, size_t data_len)
	{
	struct blkcipher_desc desc = { .tfm = tfm };
	struct scatterlist sg;
	__le32 *icv;

	icv = (__le32 *)(data + data_len);
	*icv = cpu_to_le32(~crc32_le(~0, data, data_len));

	crypto_blkcipher_setkey(tfm, rc4key, klen);
	sg.page = virt_to_page(data);
	sg.offset = offset_in_page(data);
	sg.length = data_len + WEP_ICV_LEN;
	crypto_blkcipher_encrypt(&desc, &sg, &sg, sg.length);
	}


	/* Perform WEP encryption on given skb. 4 bytes of extra space (IV) in the
	* beginning of the buffer 4 bytes of extra space (ICV) in the end of the
	* buffer will be added. Both IV and ICV will be transmitted, so the
	* payload length increases with 8 bytes.
	*
	* WEP frame payload: IV + TX key idx, RC4(data), ICV = RC4(CRC32(data))
	*/
	int ieee80211_wep_encrypt(struct ieee80211_local local, struct sk_buff skb,
	struct ieee80211_key *key)
	{
	u32 klen;
	u8 rc4key, iv;
	size_t len;

	if (!key \|\| key->alg != ALG_WEP)
	return -1;

	klen = 3 + key->keylen;
	rc4key = kmalloc(klen, GFP_ATOMIC);
	if (!rc4key)
	return -1;

	iv = ieee80211_wep_add_iv(local, skb, key);
	if (!iv) {
	kfree(rc4key);
	return -1;
	}

	len = skb->len - (iv + WEP_IV_LEN - skb->data);

	/* Prepend 24-bit IV to RC4 key */
	memcpy(rc4key, iv, 3);

	/* Copy rest of the WEP key (the secret part) */
	memcpy(rc4key + 3, key->key, key->keylen);

	/* Add room for ICV */
	skb_put(skb, WEP_ICV_LEN);

	ieee80211_wep_encrypt_data(local->wep_tx_tfm, rc4key, klen,
	iv + WEP_IV_LEN, len);

	kfree(rc4key);

	return 0;
	}


	/* Perform WEP decryption using given key. data buffer includes encrypted
	* payload, including 4-byte ICV, but _not_ IV. data_len must not include ICV.
	* Return 0 on success and -1 on ICV mismatch. */
	int ieee80211_wep_decrypt_data(struct crypto_blkcipher tfm, u8 rc4key,
	size_t klen, u8 *data, size_t data_len)
	{
	struct blkcipher_desc desc = { .tfm = tfm };
	struct scatterlist sg;
	__le32 crc;

	crypto_blkcipher_setkey(tfm, rc4key, klen);
	sg.page = virt_to_page(data);
	sg.offset = offset_in_page(data);
	sg.length = data_len + WEP_ICV_LEN;
	crypto_blkcipher_decrypt(&desc, &sg, &sg, sg.length);

	crc = cpu_to_le32(~crc32_le(~0, data, data_len));
	if (memcmp(&crc, data + data_len, WEP_ICV_LEN) != 0)
	/* ICV mismatch */
	return -1;

	return 0;
	}


	/* Perform WEP decryption on given skb. Buffer includes whole WEP part of
	* the frame: IV (4 bytes), encrypted payload (including SNAP header),
	* ICV (4 bytes). skb->len includes both IV and ICV.
	*
	* Returns 0 if frame was decrypted successfully and ICV was correct and -1 on
	* failure. If frame is OK, IV and ICV will be removed, i.e., decrypted payload
	* is moved to the beginning of the skb and skb length will be reduced.
	*/
	int ieee80211_wep_decrypt(struct ieee80211_local local, struct sk_buff skb,
	struct ieee80211_key *key)
	{
	u32 klen;
	u8 *rc4key;
	u8 keyidx;
	struct ieee80211_hdr hdr = (struct ieee80211_hdr ) skb->data;
	u16 fc;
	int hdrlen;
	size_t len;
	int ret = 0;

	fc = le16_to_cpu(hdr->frame_control);
	if (!(fc & IEEE80211_FCTL_PROTECTED))
	return -1;

	hdrlen = ieee80211_get_hdrlen(fc);

	if (skb->len < 8 + hdrlen)
	return -1;

	len = skb->len - hdrlen - 8;

	keyidx = skb->data[hdrlen + 3] >> 6;

	if (!key \|\| keyidx != key->keyidx \|\| key->alg != ALG_WEP)
	return -1;

	klen = 3 + key->keylen;

	rc4key = kmalloc(klen, GFP_ATOMIC);
	if (!rc4key)
	return -1;

	/* Prepend 24-bit IV to RC4 key */
	memcpy(rc4key, skb->data + hdrlen, 3);

	/* Copy rest of the WEP key (the secret part) */
	memcpy(rc4key + 3, key->key, key->keylen);

	if (ieee80211_wep_decrypt_data(local->wep_rx_tfm, rc4key, klen,
	skb->data + hdrlen + WEP_IV_LEN,
	len)) {
	printk(KERN_DEBUG "WEP decrypt failed (ICV)\n");
	ret = -1;
	}

	kfree(rc4key);

	/* Trim ICV */
	skb_trim(skb, skb->len - WEP_ICV_LEN);

	/* Remove IV */
	memmove(skb->data + WEP_IV_LEN, skb->data, hdrlen);
	skb_pull(skb, WEP_IV_LEN);

	return ret;
	}


	int ieee80211_wep_get_keyidx(struct sk_buff *skb)
	{
	struct ieee80211_hdr hdr = (struct ieee80211_hdr ) skb->data;
	u16 fc;
	int hdrlen;

	fc = le16_to_cpu(hdr->frame_control);
	if (!(fc & IEEE80211_FCTL_PROTECTED))
	return -1;

	hdrlen = ieee80211_get_hdrlen(fc);

	if (skb->len < 8 + hdrlen)
	return -1;

	return skb->data[hdrlen + 3] >> 6;
	}


	u8 * ieee80211_wep_is_weak_iv(struct sk_buff skb, struct ieee80211_key key)
	{
	struct ieee80211_hdr hdr = (struct ieee80211_hdr ) skb->data;
	u16 fc;
	int hdrlen;
	u8 *ivpos;
	u32 iv;

	fc = le16_to_cpu(hdr->frame_control);
	if (!(fc & IEEE80211_FCTL_PROTECTED))
	return NULL;

	hdrlen = ieee80211_get_hdrlen(fc);
	ivpos = skb->data + hdrlen;
	iv = (ivpos[0] << 16) \| (ivpos[1] << 8) \| ivpos[2];

	if (ieee80211_wep_weak_iv(iv, key->keylen))
	return ivpos;

	return NULL;
	}