--- /dev/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 <linux/scatterlist.h>
+#include <linux/slab.h>
+#include <asm/unaligned.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, IEEE80211_WEP_IV_LEN);
+
+ local->wep_tx_tfm = crypto_alloc_cipher("arc4", 0, CRYPTO_ALG_ASYNC);
+ if (IS_ERR(local->wep_tx_tfm)) {
+ local->wep_rx_tfm = ERR_PTR(-EINVAL);
+ return PTR_ERR(local->wep_tx_tfm);
+ }
+
+ local->wep_rx_tfm = crypto_alloc_cipher("arc4", 0, CRYPTO_ALG_ASYNC);
+ if (IS_ERR(local->wep_rx_tfm)) {
+ crypto_free_cipher(local->wep_tx_tfm);
+ local->wep_tx_tfm = ERR_PTR(-EINVAL);
+ return PTR_ERR(local->wep_rx_tfm);
+ }
+
+ return 0;
+}
+
+void ieee80211_wep_free(struct ieee80211_local *local)
+{
+ if (!IS_ERR(local->wep_tx_tfm))
+ crypto_free_cipher(local->wep_tx_tfm);
+ if (!IS_ERR(local->wep_rx_tfm))
+ crypto_free_cipher(local->wep_rx_tfm);
+}
+
+static inline bool 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 true;
+ }
+ return false;
+}
+
+
+static void ieee80211_wep_get_iv(struct ieee80211_local *local,
+ int keylen, int keyidx, u8 *iv)
+{
+ local->wep_iv++;
+ if (ieee80211_wep_weak_iv(local->wep_iv, 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++ = keyidx << 6;
+}
+
+
+static u8 *ieee80211_wep_add_iv(struct ieee80211_local *local,
+ struct sk_buff *skb,
+ int keylen, int keyidx)
+{
+ struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
+ struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
+ unsigned int hdrlen;
+ u8 *newhdr;
+
+ hdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
+
+ if (WARN_ON(skb_headroom(skb) < IEEE80211_WEP_IV_LEN))
+ return NULL;
+
+ hdrlen = ieee80211_hdrlen(hdr->frame_control);
+ newhdr = skb_push(skb, IEEE80211_WEP_IV_LEN);
+ memmove(newhdr, newhdr + IEEE80211_WEP_IV_LEN, hdrlen);
+
+ /* the HW only needs room for the IV, but not the actual IV */
+ if (info->control.hw_key &&
+ (info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE))
+ return newhdr + hdrlen;
+
+ ieee80211_wep_get_iv(local, keylen, keyidx, newhdr + hdrlen);
+ return newhdr + hdrlen;
+}
+
+
+static 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;
+ unsigned int hdrlen;
+
+ hdrlen = ieee80211_hdrlen(hdr->frame_control);
+ memmove(skb->data + IEEE80211_WEP_IV_LEN, skb->data, hdrlen);
+ skb_pull(skb, IEEE80211_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)) */
+int ieee80211_wep_encrypt_data(struct crypto_cipher *tfm, u8 *rc4key,
+ size_t klen, u8 *data, size_t data_len)
+{
+ __le32 icv;
+ int i;
+
+ if (IS_ERR(tfm))
+ return -1;
+
+ icv = cpu_to_le32(~crc32_le(~0, data, data_len));
+ put_unaligned(icv, (__le32 *)(data + data_len));
+
+ crypto_cipher_setkey(tfm, rc4key, klen);
+ for (i = 0; i < data_len + IEEE80211_WEP_ICV_LEN; i++)
+ crypto_cipher_encrypt_one(tfm, data + i, data + i);
+
+ return 0;
+}
+
+
+/* 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,
+ const u8 *key, int keylen, int keyidx)
+{
+ u8 *iv;
+ size_t len;
+ u8 rc4key[3 + WLAN_KEY_LEN_WEP104];
+
+ if (WARN_ON(skb_tailroom(skb) < IEEE80211_WEP_ICV_LEN))
+ return -1;
+
+ iv = ieee80211_wep_add_iv(local, skb, keylen, keyidx);
+ if (!iv)
+ return -1;
+
+ len = skb->len - (iv + IEEE80211_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, keylen);
+
+ /* Add room for ICV */
+ skb_put(skb, IEEE80211_WEP_ICV_LEN);
+
+ return ieee80211_wep_encrypt_data(local->wep_tx_tfm, rc4key, keylen + 3,
+ iv + IEEE80211_WEP_IV_LEN, len);
+}
+
+
+/* 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_cipher *tfm, u8 *rc4key,
+ size_t klen, u8 *data, size_t data_len)
+{
+ __le32 crc;
+ int i;
+
+ if (IS_ERR(tfm))
+ return -1;
+
+ crypto_cipher_setkey(tfm, rc4key, klen);
+ for (i = 0; i < data_len + IEEE80211_WEP_ICV_LEN; i++)
+ crypto_cipher_decrypt_one(tfm, data + i, data + i);
+
+ crc = cpu_to_le32(~crc32_le(~0, data, data_len));
+ if (memcmp(&crc, data + data_len, IEEE80211_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.
+ */
+static int ieee80211_wep_decrypt(struct ieee80211_local *local,
+ struct sk_buff *skb,
+ struct ieee80211_key *key)
+{
+ u32 klen;
+ u8 rc4key[3 + WLAN_KEY_LEN_WEP104];
+ u8 keyidx;
+ struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
+ unsigned int hdrlen;
+ size_t len;
+ int ret = 0;
+
+ if (!ieee80211_has_protected(hdr->frame_control))
+ return -1;
+
+ hdrlen = ieee80211_hdrlen(hdr->frame_control);
+ if (skb->len < hdrlen + IEEE80211_WEP_IV_LEN + IEEE80211_WEP_ICV_LEN)
+ return -1;
+
+ len = skb->len - hdrlen - IEEE80211_WEP_IV_LEN - IEEE80211_WEP_ICV_LEN;
+
+ keyidx = skb->data[hdrlen + 3] >> 6;
+
+ if (!key || keyidx != key->conf.keyidx)
+ return -1;
+
+ klen = 3 + key->conf.keylen;
+
+ /* 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->conf.key, key->conf.keylen);
+
+ if (ieee80211_wep_decrypt_data(local->wep_rx_tfm, rc4key, klen,
+ skb->data + hdrlen +
+ IEEE80211_WEP_IV_LEN, len))
+ ret = -1;
+
+ /* Trim ICV */
+ skb_trim(skb, skb->len - IEEE80211_WEP_ICV_LEN);
+
+ /* Remove IV */
+ memmove(skb->data + IEEE80211_WEP_IV_LEN, skb->data, hdrlen);
+ skb_pull(skb, IEEE80211_WEP_IV_LEN);
+
+ return ret;
+}
+
+ieee80211_rx_result
+ieee80211_crypto_wep_decrypt(struct ieee80211_rx_data *rx)
+{
+ struct sk_buff *skb = rx->skb;
+ struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
+ struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
+ __le16 fc = hdr->frame_control;
+
+ if (!ieee80211_is_data(fc) && !ieee80211_is_auth(fc))
+ return RX_CONTINUE;
+
+ if (!(status->flag & RX_FLAG_DECRYPTED)) {
+ if (skb_linearize(rx->skb))
+ return RX_DROP_UNUSABLE;
+ if (ieee80211_wep_decrypt(rx->local, rx->skb, rx->key))
+ return RX_DROP_UNUSABLE;
+ } else if (!(status->flag & RX_FLAG_IV_STRIPPED)) {
+ if (!pskb_may_pull(rx->skb, ieee80211_hdrlen(fc) +
+ IEEE80211_WEP_IV_LEN))
+ return RX_DROP_UNUSABLE;
+ ieee80211_wep_remove_iv(rx->local, rx->skb, rx->key);
+ /* remove ICV */
+ if (pskb_trim(rx->skb, rx->skb->len - IEEE80211_WEP_ICV_LEN))
+ return RX_DROP_UNUSABLE;
+ }
+
+ return RX_CONTINUE;
+}
+
+static int wep_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
+{
+ struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
+ struct ieee80211_key_conf *hw_key = info->control.hw_key;
+
+ if (!hw_key) {
+ if (ieee80211_wep_encrypt(tx->local, skb, tx->key->conf.key,
+ tx->key->conf.keylen,
+ tx->key->conf.keyidx))
+ return -1;
+ } else if ((hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV) ||
+ (hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)) {
+ if (!ieee80211_wep_add_iv(tx->local, skb,
+ tx->key->conf.keylen,
+ tx->key->conf.keyidx))
+ return -1;
+ }
+
+ return 0;
+}
+
+ieee80211_tx_result
+ieee80211_crypto_wep_encrypt(struct ieee80211_tx_data *tx)
+{
+ struct sk_buff *skb;
+
+ ieee80211_tx_set_protected(tx);
+
+ skb_queue_walk(&tx->skbs, skb) {
+ if (wep_encrypt_skb(tx, skb) < 0) {
+ I802_DEBUG_INC(tx->local->tx_handlers_drop_wep);
+ return TX_DROP;
+ }
+ }
+
+ return TX_CONTINUE;
+}
Code Review / kvmfornfv.git / blobdiff