Greg Kroah-Hartman | ecdfa44 | 2009-08-04 15:57:55 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Host AP crypt: host-based WEP encryption implementation for Host AP driver |
| 3 | * |
| 4 | * Copyright (c) 2002-2004, Jouni Malinen <jkmaline@cc.hut.fi> |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License version 2 as |
| 8 | * published by the Free Software Foundation. See README and COPYING for |
| 9 | * more details. |
| 10 | */ |
| 11 | |
Greg Kroah-Hartman | ecdfa44 | 2009-08-04 15:57:55 -0700 | [diff] [blame] | 12 | #include <linux/module.h> |
| 13 | #include <linux/init.h> |
| 14 | #include <linux/slab.h> |
| 15 | #include <linux/random.h> |
| 16 | #include <linux/skbuff.h> |
Larry Finger | a44325f | 2011-08-25 11:48:23 -0500 | [diff] [blame] | 17 | #include <linux/string.h> |
Larry Finger | 94a7994 | 2011-08-23 19:00:42 -0500 | [diff] [blame] | 18 | #include "rtllib.h" |
Greg Kroah-Hartman | ecdfa44 | 2009-08-04 15:57:55 -0700 | [diff] [blame] | 19 | |
Larry Finger | 94a7994 | 2011-08-23 19:00:42 -0500 | [diff] [blame] | 20 | #include <linux/crypto.h> |
Larry Finger | 94a7994 | 2011-08-23 19:00:42 -0500 | [diff] [blame] | 21 | |
Mike McCormack | cb76215 | 2011-07-11 08:56:20 +0900 | [diff] [blame] | 22 | #include <linux/scatterlist.h> |
Larry Finger | 94a7994 | 2011-08-23 19:00:42 -0500 | [diff] [blame] | 23 | #include <linux/crc32.h> |
Larry Finger | 94a7994 | 2011-08-23 19:00:42 -0500 | [diff] [blame] | 24 | |
Greg Kroah-Hartman | ecdfa44 | 2009-08-04 15:57:55 -0700 | [diff] [blame] | 25 | struct prism2_wep_data { |
| 26 | u32 iv; |
| 27 | #define WEP_KEY_LEN 13 |
| 28 | u8 key[WEP_KEY_LEN + 1]; |
| 29 | u8 key_len; |
| 30 | u8 key_idx; |
Larry Finger | a44325f | 2011-08-25 11:48:23 -0500 | [diff] [blame] | 31 | struct crypto_blkcipher *tx_tfm; |
| 32 | struct crypto_blkcipher *rx_tfm; |
Greg Kroah-Hartman | ecdfa44 | 2009-08-04 15:57:55 -0700 | [diff] [blame] | 33 | }; |
| 34 | |
| 35 | |
Larry Finger | a44325f | 2011-08-25 11:48:23 -0500 | [diff] [blame] | 36 | static void *prism2_wep_init(int keyidx) |
Greg Kroah-Hartman | ecdfa44 | 2009-08-04 15:57:55 -0700 | [diff] [blame] | 37 | { |
| 38 | struct prism2_wep_data *priv; |
| 39 | |
Thomas Meyer | 929fa2a | 2011-11-10 19:04:19 +0100 | [diff] [blame] | 40 | priv = kzalloc(sizeof(*priv), GFP_ATOMIC); |
Greg Kroah-Hartman | ecdfa44 | 2009-08-04 15:57:55 -0700 | [diff] [blame] | 41 | if (priv == NULL) |
| 42 | goto fail; |
Greg Kroah-Hartman | ecdfa44 | 2009-08-04 15:57:55 -0700 | [diff] [blame] | 43 | priv->key_idx = keyidx; |
| 44 | |
Greg Kroah-Hartman | ecdfa44 | 2009-08-04 15:57:55 -0700 | [diff] [blame] | 45 | priv->tx_tfm = crypto_alloc_blkcipher("ecb(arc4)", 0, CRYPTO_ALG_ASYNC); |
Larry Finger | a44325f | 2011-08-25 11:48:23 -0500 | [diff] [blame] | 46 | if (IS_ERR(priv->tx_tfm)) { |
| 47 | printk(KERN_DEBUG "rtllib_crypt_wep: could not allocate " |
| 48 | "crypto API arc4\n"); |
| 49 | priv->tx_tfm = NULL; |
| 50 | goto fail; |
| 51 | } |
| 52 | priv->rx_tfm = crypto_alloc_blkcipher("ecb(arc4)", 0, CRYPTO_ALG_ASYNC); |
| 53 | if (IS_ERR(priv->rx_tfm)) { |
| 54 | printk(KERN_DEBUG "rtllib_crypt_wep: could not allocate " |
| 55 | "crypto API arc4\n"); |
| 56 | priv->rx_tfm = NULL; |
| 57 | goto fail; |
| 58 | } |
Greg Kroah-Hartman | ecdfa44 | 2009-08-04 15:57:55 -0700 | [diff] [blame] | 59 | |
| 60 | /* start WEP IV from a random value */ |
| 61 | get_random_bytes(&priv->iv, 4); |
| 62 | |
| 63 | return priv; |
| 64 | |
| 65 | fail: |
Greg Kroah-Hartman | ecdfa44 | 2009-08-04 15:57:55 -0700 | [diff] [blame] | 66 | if (priv) { |
Larry Finger | a44325f | 2011-08-25 11:48:23 -0500 | [diff] [blame] | 67 | if (priv->tx_tfm) |
| 68 | crypto_free_blkcipher(priv->tx_tfm); |
| 69 | if (priv->rx_tfm) |
| 70 | crypto_free_blkcipher(priv->rx_tfm); |
| 71 | kfree(priv); |
| 72 | } |
Greg Kroah-Hartman | ecdfa44 | 2009-08-04 15:57:55 -0700 | [diff] [blame] | 73 | return NULL; |
| 74 | } |
| 75 | |
| 76 | |
| 77 | static void prism2_wep_deinit(void *priv) |
| 78 | { |
| 79 | struct prism2_wep_data *_priv = priv; |
Mike McCormack | cb76215 | 2011-07-11 08:56:20 +0900 | [diff] [blame] | 80 | |
Greg Kroah-Hartman | ecdfa44 | 2009-08-04 15:57:55 -0700 | [diff] [blame] | 81 | if (_priv) { |
Larry Finger | a44325f | 2011-08-25 11:48:23 -0500 | [diff] [blame] | 82 | if (_priv->tx_tfm) |
| 83 | crypto_free_blkcipher(_priv->tx_tfm); |
| 84 | if (_priv->rx_tfm) |
| 85 | crypto_free_blkcipher(_priv->rx_tfm); |
| 86 | } |
Greg Kroah-Hartman | ecdfa44 | 2009-08-04 15:57:55 -0700 | [diff] [blame] | 87 | kfree(priv); |
| 88 | } |
| 89 | |
| 90 | /* Perform WEP encryption on given skb that has at least 4 bytes of headroom |
| 91 | * for IV and 4 bytes of tailroom for ICV. Both IV and ICV will be transmitted, |
| 92 | * so the payload length increases with 8 bytes. |
| 93 | * |
| 94 | * WEP frame payload: IV + TX key idx, RC4(data), ICV = RC4(CRC32(data)) |
| 95 | */ |
| 96 | static int prism2_wep_encrypt(struct sk_buff *skb, int hdr_len, void *priv) |
| 97 | { |
| 98 | struct prism2_wep_data *wep = priv; |
| 99 | u32 klen, len; |
| 100 | u8 key[WEP_KEY_LEN + 3]; |
| 101 | u8 *pos; |
Larry Finger | a44325f | 2011-08-25 11:48:23 -0500 | [diff] [blame] | 102 | struct cb_desc *tcb_desc = (struct cb_desc *)(skb->cb + |
| 103 | MAX_DEV_ADDR_SIZE); |
Greg Kroah-Hartman | ecdfa44 | 2009-08-04 15:57:55 -0700 | [diff] [blame] | 104 | struct blkcipher_desc desc = {.tfm = wep->tx_tfm}; |
Greg Kroah-Hartman | ecdfa44 | 2009-08-04 15:57:55 -0700 | [diff] [blame] | 105 | u32 crc; |
| 106 | u8 *icv; |
| 107 | struct scatterlist sg; |
| 108 | if (skb_headroom(skb) < 4 || skb_tailroom(skb) < 4 || |
Larry Finger | 94a7994 | 2011-08-23 19:00:42 -0500 | [diff] [blame] | 109 | skb->len < hdr_len){ |
Larry Finger | a44325f | 2011-08-25 11:48:23 -0500 | [diff] [blame] | 110 | printk(KERN_ERR "Error!!! headroom=%d tailroom=%d skblen=%d" |
| 111 | " hdr_len=%d\n", skb_headroom(skb), skb_tailroom(skb), |
| 112 | skb->len, hdr_len); |
Greg Kroah-Hartman | ecdfa44 | 2009-08-04 15:57:55 -0700 | [diff] [blame] | 113 | return -1; |
Larry Finger | 94a7994 | 2011-08-23 19:00:42 -0500 | [diff] [blame] | 114 | } |
Greg Kroah-Hartman | ecdfa44 | 2009-08-04 15:57:55 -0700 | [diff] [blame] | 115 | len = skb->len - hdr_len; |
| 116 | pos = skb_push(skb, 4); |
| 117 | memmove(pos, pos + 4, hdr_len); |
| 118 | pos += hdr_len; |
| 119 | |
| 120 | klen = 3 + wep->key_len; |
| 121 | |
| 122 | wep->iv++; |
| 123 | |
| 124 | /* Fluhrer, Mantin, and Shamir have reported weaknesses in the key |
| 125 | * scheduling algorithm of RC4. At least IVs (KeyByte + 3, 0xff, N) |
| 126 | * can be used to speedup attacks, so avoid using them. */ |
| 127 | if ((wep->iv & 0xff00) == 0xff00) { |
| 128 | u8 B = (wep->iv >> 16) & 0xff; |
| 129 | if (B >= 3 && B < klen) |
| 130 | wep->iv += 0x0100; |
| 131 | } |
| 132 | |
| 133 | /* Prepend 24-bit IV to RC4 key and TX frame */ |
| 134 | *pos++ = key[0] = (wep->iv >> 16) & 0xff; |
| 135 | *pos++ = key[1] = (wep->iv >> 8) & 0xff; |
| 136 | *pos++ = key[2] = wep->iv & 0xff; |
| 137 | *pos++ = wep->key_idx << 6; |
| 138 | |
| 139 | /* Copy rest of the WEP key (the secret part) */ |
| 140 | memcpy(key + 3, wep->key, wep->key_len); |
| 141 | |
Mike McCormack | cb76215 | 2011-07-11 08:56:20 +0900 | [diff] [blame] | 142 | if (!tcb_desc->bHwSec) { |
Greg Kroah-Hartman | ecdfa44 | 2009-08-04 15:57:55 -0700 | [diff] [blame] | 143 | |
| 144 | /* Append little-endian CRC32 and encrypt it to produce ICV */ |
Greg Kroah-Hartman | ecdfa44 | 2009-08-04 15:57:55 -0700 | [diff] [blame] | 145 | crc = ~crc32_le(~0, pos, len); |
Greg Kroah-Hartman | ecdfa44 | 2009-08-04 15:57:55 -0700 | [diff] [blame] | 146 | icv = skb_put(skb, 4); |
| 147 | icv[0] = crc; |
| 148 | icv[1] = crc >> 8; |
| 149 | icv[2] = crc >> 16; |
| 150 | icv[3] = crc >> 24; |
| 151 | |
Greg Kroah-Hartman | ecdfa44 | 2009-08-04 15:57:55 -0700 | [diff] [blame] | 152 | sg_init_one(&sg, pos, len+4); |
Larry Finger | 94a7994 | 2011-08-23 19:00:42 -0500 | [diff] [blame] | 153 | crypto_blkcipher_setkey(wep->tx_tfm, key, klen); |
Greg Kroah-Hartman | ecdfa44 | 2009-08-04 15:57:55 -0700 | [diff] [blame] | 154 | return crypto_blkcipher_encrypt(&desc, &sg, &sg, len + 4); |
Greg Kroah-Hartman | ecdfa44 | 2009-08-04 15:57:55 -0700 | [diff] [blame] | 155 | } |
| 156 | |
| 157 | return 0; |
| 158 | } |
| 159 | |
| 160 | |
Larry Finger | a44325f | 2011-08-25 11:48:23 -0500 | [diff] [blame] | 161 | /* Perform WEP decryption on given struct buffer. Buffer includes whole WEP |
| 162 | * part of the frame: IV (4 bytes), encrypted payload (including SNAP header), |
Greg Kroah-Hartman | ecdfa44 | 2009-08-04 15:57:55 -0700 | [diff] [blame] | 163 | * ICV (4 bytes). len includes both IV and ICV. |
| 164 | * |
| 165 | * Returns 0 if frame was decrypted successfully and ICV was correct and -1 on |
| 166 | * failure. If frame is OK, IV and ICV will be removed. |
| 167 | */ |
| 168 | static int prism2_wep_decrypt(struct sk_buff *skb, int hdr_len, void *priv) |
| 169 | { |
| 170 | struct prism2_wep_data *wep = priv; |
| 171 | u32 klen, plen; |
| 172 | u8 key[WEP_KEY_LEN + 3]; |
| 173 | u8 keyidx, *pos; |
Larry Finger | a44325f | 2011-08-25 11:48:23 -0500 | [diff] [blame] | 174 | struct cb_desc *tcb_desc = (struct cb_desc *)(skb->cb + |
| 175 | MAX_DEV_ADDR_SIZE); |
Greg Kroah-Hartman | ecdfa44 | 2009-08-04 15:57:55 -0700 | [diff] [blame] | 176 | struct blkcipher_desc desc = {.tfm = wep->rx_tfm}; |
Greg Kroah-Hartman | ecdfa44 | 2009-08-04 15:57:55 -0700 | [diff] [blame] | 177 | u32 crc; |
| 178 | u8 icv[4]; |
| 179 | struct scatterlist sg; |
| 180 | if (skb->len < hdr_len + 8) |
| 181 | return -1; |
| 182 | |
| 183 | pos = skb->data + hdr_len; |
| 184 | key[0] = *pos++; |
| 185 | key[1] = *pos++; |
| 186 | key[2] = *pos++; |
| 187 | keyidx = *pos++ >> 6; |
| 188 | if (keyidx != wep->key_idx) |
| 189 | return -1; |
| 190 | |
| 191 | klen = 3 + wep->key_len; |
| 192 | |
| 193 | /* Copy rest of the WEP key (the secret part) */ |
| 194 | memcpy(key + 3, wep->key, wep->key_len); |
| 195 | |
| 196 | /* Apply RC4 to data and compute CRC32 over decrypted data */ |
| 197 | plen = skb->len - hdr_len - 8; |
| 198 | |
Mike McCormack | cb76215 | 2011-07-11 08:56:20 +0900 | [diff] [blame] | 199 | if (!tcb_desc->bHwSec) { |
Greg Kroah-Hartman | ecdfa44 | 2009-08-04 15:57:55 -0700 | [diff] [blame] | 200 | sg_init_one(&sg, pos, plen+4); |
Larry Finger | 94a7994 | 2011-08-23 19:00:42 -0500 | [diff] [blame] | 201 | crypto_blkcipher_setkey(wep->rx_tfm, key, klen); |
Greg Kroah-Hartman | ecdfa44 | 2009-08-04 15:57:55 -0700 | [diff] [blame] | 202 | if (crypto_blkcipher_decrypt(&desc, &sg, &sg, plen + 4)) |
| 203 | return -7; |
Greg Kroah-Hartman | ecdfa44 | 2009-08-04 15:57:55 -0700 | [diff] [blame] | 204 | crc = ~crc32_le(~0, pos, plen); |
Greg Kroah-Hartman | ecdfa44 | 2009-08-04 15:57:55 -0700 | [diff] [blame] | 205 | icv[0] = crc; |
| 206 | icv[1] = crc >> 8; |
| 207 | icv[2] = crc >> 16; |
| 208 | icv[3] = crc >> 24; |
| 209 | if (memcmp(icv, pos + plen, 4) != 0) { |
| 210 | /* ICV mismatch - drop frame */ |
| 211 | return -2; |
| 212 | } |
| 213 | } |
| 214 | /* Remove IV and ICV */ |
| 215 | memmove(skb->data + 4, skb->data, hdr_len); |
| 216 | skb_pull(skb, 4); |
| 217 | skb_trim(skb, skb->len - 4); |
| 218 | |
| 219 | return 0; |
| 220 | } |
| 221 | |
| 222 | |
| 223 | static int prism2_wep_set_key(void *key, int len, u8 *seq, void *priv) |
| 224 | { |
| 225 | struct prism2_wep_data *wep = priv; |
| 226 | |
| 227 | if (len < 0 || len > WEP_KEY_LEN) |
| 228 | return -1; |
| 229 | |
| 230 | memcpy(wep->key, key, len); |
| 231 | wep->key_len = len; |
| 232 | |
| 233 | return 0; |
| 234 | } |
| 235 | |
| 236 | |
| 237 | static int prism2_wep_get_key(void *key, int len, u8 *seq, void *priv) |
| 238 | { |
| 239 | struct prism2_wep_data *wep = priv; |
| 240 | |
| 241 | if (len < wep->key_len) |
| 242 | return -1; |
| 243 | |
| 244 | memcpy(key, wep->key, wep->key_len); |
| 245 | |
| 246 | return wep->key_len; |
| 247 | } |
| 248 | |
| 249 | |
David Howells | 6bbefe8 | 2013-04-10 21:13:23 +0100 | [diff] [blame] | 250 | static void prism2_wep_print_stats(struct seq_file *m, void *priv) |
Greg Kroah-Hartman | ecdfa44 | 2009-08-04 15:57:55 -0700 | [diff] [blame] | 251 | { |
| 252 | struct prism2_wep_data *wep = priv; |
David Howells | 6bbefe8 | 2013-04-10 21:13:23 +0100 | [diff] [blame] | 253 | seq_printf(m, "key[%d] alg=WEP len=%d\n", wep->key_idx, wep->key_len); |
Greg Kroah-Hartman | ecdfa44 | 2009-08-04 15:57:55 -0700 | [diff] [blame] | 254 | } |
| 255 | |
Sean MacLennan | 32c44cb | 2011-12-19 23:20:41 -0500 | [diff] [blame] | 256 | static struct lib80211_crypto_ops rtllib_crypt_wep = { |
Sean MacLennan | 3b148be | 2011-12-19 23:23:08 -0500 | [diff] [blame] | 257 | .name = "R-WEP", |
Greg Kroah-Hartman | ecdfa44 | 2009-08-04 15:57:55 -0700 | [diff] [blame] | 258 | .init = prism2_wep_init, |
| 259 | .deinit = prism2_wep_deinit, |
| 260 | .encrypt_mpdu = prism2_wep_encrypt, |
| 261 | .decrypt_mpdu = prism2_wep_decrypt, |
| 262 | .encrypt_msdu = NULL, |
| 263 | .decrypt_msdu = NULL, |
| 264 | .set_key = prism2_wep_set_key, |
| 265 | .get_key = prism2_wep_get_key, |
| 266 | .print_stats = prism2_wep_print_stats, |
Sean MacLennan | 32c44cb | 2011-12-19 23:20:41 -0500 | [diff] [blame] | 267 | .extra_mpdu_prefix_len = 4, /* IV */ |
| 268 | .extra_mpdu_postfix_len = 4, /* ICV */ |
Greg Kroah-Hartman | ecdfa44 | 2009-08-04 15:57:55 -0700 | [diff] [blame] | 269 | .owner = THIS_MODULE, |
| 270 | }; |
| 271 | |
| 272 | |
Larry Finger | 94a7994 | 2011-08-23 19:00:42 -0500 | [diff] [blame] | 273 | int __init rtllib_crypto_wep_init(void) |
Greg Kroah-Hartman | ecdfa44 | 2009-08-04 15:57:55 -0700 | [diff] [blame] | 274 | { |
Sean MacLennan | 3b148be | 2011-12-19 23:23:08 -0500 | [diff] [blame] | 275 | return lib80211_register_crypto_ops(&rtllib_crypt_wep); |
Greg Kroah-Hartman | ecdfa44 | 2009-08-04 15:57:55 -0700 | [diff] [blame] | 276 | } |
| 277 | |
| 278 | |
Larry Finger | 94a7994 | 2011-08-23 19:00:42 -0500 | [diff] [blame] | 279 | void __exit rtllib_crypto_wep_exit(void) |
Greg Kroah-Hartman | ecdfa44 | 2009-08-04 15:57:55 -0700 | [diff] [blame] | 280 | { |
Sean MacLennan | 3b148be | 2011-12-19 23:23:08 -0500 | [diff] [blame] | 281 | lib80211_unregister_crypto_ops(&rtllib_crypt_wep); |
Greg Kroah-Hartman | ecdfa44 | 2009-08-04 15:57:55 -0700 | [diff] [blame] | 282 | } |
| 283 | |
Sean MacLennan | d37e020 | 2011-11-28 20:21:27 -0500 | [diff] [blame] | 284 | module_init(rtllib_crypto_wep_init); |
| 285 | module_exit(rtllib_crypto_wep_exit); |
| 286 | |
| 287 | MODULE_LICENSE("GPL"); |