1/* 2 * Host AP crypt: host-based CCMP encryption implementation for Host AP driver 3 * 4 * Copyright (c) 2003-2004, 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 12//#include <linux/config.h> 13#include <linux/version.h> 14#include <linux/module.h> 15#include <linux/init.h> 16#include <linux/slab.h> 17#include <linux/random.h> 18#include <linux/skbuff.h> 19#include <linux/netdevice.h> 20#include <linux/if_ether.h> 21#include <linux/if_arp.h> 22#include <asm/string.h> 23#include <linux/wireless.h> 24 25#include "ieee80211.h" 26 27#include <linux/crypto.h> 28#include <linux/scatterlist.h> 29 30MODULE_AUTHOR("Jouni Malinen"); 31MODULE_DESCRIPTION("Host AP crypt: CCMP"); 32MODULE_LICENSE("GPL"); 33 34 35#define AES_BLOCK_LEN 16 36#define CCMP_HDR_LEN 8 37#define CCMP_MIC_LEN 8 38#define CCMP_TK_LEN 16 39#define CCMP_PN_LEN 6 40 41struct ieee80211_ccmp_data { 42 u8 key[CCMP_TK_LEN]; 43 int key_set; 44 45 u8 tx_pn[CCMP_PN_LEN]; 46 u8 rx_pn[CCMP_PN_LEN]; 47 48 u32 dot11RSNAStatsCCMPFormatErrors; 49 u32 dot11RSNAStatsCCMPReplays; 50 u32 dot11RSNAStatsCCMPDecryptErrors; 51 52 int key_idx; 53 54 struct crypto_tfm *tfm; 55 56 /* scratch buffers for virt_to_page() (crypto API) */ 57 u8 tx_b0[AES_BLOCK_LEN], tx_b[AES_BLOCK_LEN], 58 tx_e[AES_BLOCK_LEN], tx_s0[AES_BLOCK_LEN]; 59 u8 rx_b0[AES_BLOCK_LEN], rx_b[AES_BLOCK_LEN], rx_a[AES_BLOCK_LEN]; 60}; 61 62void ieee80211_ccmp_aes_encrypt(struct crypto_tfm *tfm, 63 const u8 pt[16], u8 ct[16]) 64{ 65 crypto_cipher_encrypt_one((void *)tfm, ct, pt); 66} 67 68static void * ieee80211_ccmp_init(int key_idx) 69{ 70 struct ieee80211_ccmp_data *priv; 71 72 priv = kzalloc(sizeof(*priv), GFP_ATOMIC); 73 if (priv == NULL) 74 goto fail; 75 priv->key_idx = key_idx; 76 77 priv->tfm = (void *)crypto_alloc_cipher("aes", 0, CRYPTO_ALG_ASYNC); 78 if (IS_ERR(priv->tfm)) { 79 printk(KERN_DEBUG "ieee80211_crypt_ccmp: could not allocate " 80 "crypto API aes\n"); 81 priv->tfm = NULL; 82 goto fail; 83 } 84 85 return priv; 86 87fail: 88 if (priv) { 89 if (priv->tfm) 90 crypto_free_cipher((void *)priv->tfm); 91 kfree(priv); 92 } 93 94 return NULL; 95} 96 97 98static void ieee80211_ccmp_deinit(void *priv) 99{ 100 struct ieee80211_ccmp_data *_priv = priv; 101 102 if (_priv && _priv->tfm) 103 crypto_free_cipher((void *)_priv->tfm); 104 kfree(priv); 105} 106 107 108static inline void xor_block(u8 *b, u8 *a, size_t len) 109{ 110 int i; 111 for (i = 0; i < len; i++) 112 b[i] ^= a[i]; 113} 114 115static void ccmp_init_blocks(struct crypto_tfm *tfm, 116 struct ieee80211_hdr_4addr *hdr, 117 u8 *pn, size_t dlen, u8 *b0, u8 *auth, 118 u8 *s0) 119{ 120 u8 *pos, qc = 0; 121 size_t aad_len; 122 u16 fc; 123 int a4_included, qc_included; 124 u8 aad[2 * AES_BLOCK_LEN]; 125 126 fc = le16_to_cpu(hdr->frame_ctl); 127 a4_included = ((fc & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) == 128 (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)); 129 /* 130 qc_included = ((WLAN_FC_GET_TYPE(fc) == IEEE80211_FTYPE_DATA) && 131 (WLAN_FC_GET_STYPE(fc) & 0x08)); 132 */ 133 // fixed by David :2006.9.6 134 qc_included = ((WLAN_FC_GET_TYPE(fc) == IEEE80211_FTYPE_DATA) && 135 (WLAN_FC_GET_STYPE(fc) & 0x80)); 136 aad_len = 22; 137 if (a4_included) 138 aad_len += 6; 139 if (qc_included) { 140 pos = (u8 *) &hdr->addr4; 141 if (a4_included) 142 pos += 6; 143 qc = *pos & 0x0f; 144 aad_len += 2; 145 } 146 /* CCM Initial Block: 147 * Flag (Include authentication header, M=3 (8-octet MIC), 148 * L=1 (2-octet Dlen)) 149 * Nonce: 0x00 | A2 | PN 150 * Dlen */ 151 b0[0] = 0x59; 152 b0[1] = qc; 153 memcpy(b0 + 2, hdr->addr2, ETH_ALEN); 154 memcpy(b0 + 8, pn, CCMP_PN_LEN); 155 b0[14] = (dlen >> 8) & 0xff; 156 b0[15] = dlen & 0xff; 157 158 /* AAD: 159 * FC with bits 4..6 and 11..13 masked to zero; 14 is always one 160 * A1 | A2 | A3 161 * SC with bits 4..15 (seq#) masked to zero 162 * A4 (if present) 163 * QC (if present) 164 */ 165 pos = (u8 *) hdr; 166 aad[0] = 0; /* aad_len >> 8 */ 167 aad[1] = aad_len & 0xff; 168 aad[2] = pos[0] & 0x8f; 169 aad[3] = pos[1] & 0xc7; 170 memcpy(aad + 4, hdr->addr1, 3 * ETH_ALEN); 171 pos = (u8 *) &hdr->seq_ctl; 172 aad[22] = pos[0] & 0x0f; 173 aad[23] = 0; /* all bits masked */ 174 memset(aad + 24, 0, 8); 175 if (a4_included) 176 memcpy(aad + 24, hdr->addr4, ETH_ALEN); 177 if (qc_included) { 178 aad[a4_included ? 30 : 24] = qc; 179 /* rest of QC masked */ 180 } 181 182 /* Start with the first block and AAD */ 183 ieee80211_ccmp_aes_encrypt(tfm, b0, auth); 184 xor_block(auth, aad, AES_BLOCK_LEN); 185 ieee80211_ccmp_aes_encrypt(tfm, auth, auth); 186 xor_block(auth, &aad[AES_BLOCK_LEN], AES_BLOCK_LEN); 187 ieee80211_ccmp_aes_encrypt(tfm, auth, auth); 188 b0[0] &= 0x07; 189 b0[14] = b0[15] = 0; 190 ieee80211_ccmp_aes_encrypt(tfm, b0, s0); 191} 192 193static int ieee80211_ccmp_encrypt(struct sk_buff *skb, int hdr_len, void *priv) 194{ 195 struct ieee80211_ccmp_data *key = priv; 196 int data_len, i; 197 u8 *pos; 198 struct ieee80211_hdr_4addr *hdr; 199 int blocks, last, len; 200 u8 *mic; 201 u8 *b0 = key->tx_b0; 202 u8 *b = key->tx_b; 203 u8 *e = key->tx_e; 204 u8 *s0 = key->tx_s0; 205 206 if (skb_headroom(skb) < CCMP_HDR_LEN || 207 skb_tailroom(skb) < CCMP_MIC_LEN || 208 skb->len < hdr_len) 209 return -1; 210 211 data_len = skb->len - hdr_len; 212 pos = skb_push(skb, CCMP_HDR_LEN); 213 memmove(pos, pos + CCMP_HDR_LEN, hdr_len); 214 pos += hdr_len; 215// mic = skb_put(skb, CCMP_MIC_LEN); 216 217 i = CCMP_PN_LEN - 1; 218 while (i >= 0) { 219 key->tx_pn[i]++; 220 if (key->tx_pn[i] != 0) 221 break; 222 i--; 223 } 224 225 *pos++ = key->tx_pn[5]; 226 *pos++ = key->tx_pn[4]; 227 *pos++ = 0; 228 *pos++ = (key->key_idx << 6) | (1 << 5) /* Ext IV included */; 229 *pos++ = key->tx_pn[3]; 230 *pos++ = key->tx_pn[2]; 231 *pos++ = key->tx_pn[1]; 232 *pos++ = key->tx_pn[0]; 233 234 hdr = (struct ieee80211_hdr_4addr *)skb->data; 235 //mic is moved to here by john 236 mic = skb_put(skb, CCMP_MIC_LEN); 237 238 ccmp_init_blocks(key->tfm, hdr, key->tx_pn, data_len, b0, b, s0); 239 240 blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN; 241 last = data_len % AES_BLOCK_LEN; 242 243 for (i = 1; i <= blocks; i++) { 244 len = (i == blocks && last) ? last : AES_BLOCK_LEN; 245 /* Authentication */ 246 xor_block(b, pos, len); 247 ieee80211_ccmp_aes_encrypt(key->tfm, b, b); 248 /* Encryption, with counter */ 249 b0[14] = (i >> 8) & 0xff; 250 b0[15] = i & 0xff; 251 ieee80211_ccmp_aes_encrypt(key->tfm, b0, e); 252 xor_block(pos, e, len); 253 pos += len; 254 } 255 256 for (i = 0; i < CCMP_MIC_LEN; i++) 257 mic[i] = b[i] ^ s0[i]; 258 259 return 0; 260} 261 262 263static int ieee80211_ccmp_decrypt(struct sk_buff *skb, int hdr_len, void *priv) 264{ 265 struct ieee80211_ccmp_data *key = priv; 266 u8 keyidx, *pos; 267 struct ieee80211_hdr_4addr *hdr; 268 u8 pn[6]; 269 size_t data_len = skb->len - hdr_len - CCMP_HDR_LEN - CCMP_MIC_LEN; 270 u8 *mic = skb->data + skb->len - CCMP_MIC_LEN; 271 u8 *b0 = key->rx_b0; 272 u8 *b = key->rx_b; 273 u8 *a = key->rx_a; 274 int i, blocks, last, len; 275 276 if (skb->len < hdr_len + CCMP_HDR_LEN + CCMP_MIC_LEN) { 277 key->dot11RSNAStatsCCMPFormatErrors++; 278 return -1; 279 } 280 281 hdr = (struct ieee80211_hdr_4addr *)skb->data; 282 pos = skb->data + hdr_len; 283 keyidx = pos[3]; 284 if (!(keyidx & (1 << 5))) { 285 if (net_ratelimit()) { 286 printk(KERN_DEBUG "CCMP: received packet without ExtIV" 287 " flag from %pM\n", hdr->addr2); 288 } 289 key->dot11RSNAStatsCCMPFormatErrors++; 290 return -2; 291 } 292 keyidx >>= 6; 293 if (key->key_idx != keyidx) { 294 printk(KERN_DEBUG "CCMP: RX tkey->key_idx=%d frame " 295 "keyidx=%d priv=%p\n", key->key_idx, keyidx, priv); 296 return -6; 297 } 298 if (!key->key_set) { 299 if (net_ratelimit()) { 300 printk(KERN_DEBUG "CCMP: received packet from %pM" 301 " with keyid=%d that does not have a configured" 302 " key\n", hdr->addr2, keyidx); 303 } 304 return -3; 305 } 306 307 pn[0] = pos[7]; 308 pn[1] = pos[6]; 309 pn[2] = pos[5]; 310 pn[3] = pos[4]; 311 pn[4] = pos[1]; 312 pn[5] = pos[0]; 313 pos += 8; 314 315 if (memcmp(pn, key->rx_pn, CCMP_PN_LEN) <= 0) { 316 if (net_ratelimit()) { 317 printk(KERN_DEBUG "CCMP: replay detected: STA=%pM" 318 " previous PN %pm received PN %pm\n", 319 hdr->addr2, key->rx_pn, pn); 320 } 321 key->dot11RSNAStatsCCMPReplays++; 322 return -4; 323 } 324 325 ccmp_init_blocks(key->tfm, hdr, pn, data_len, b0, a, b); 326 xor_block(mic, b, CCMP_MIC_LEN); 327 328 blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN; 329 last = data_len % AES_BLOCK_LEN; 330 331 for (i = 1; i <= blocks; i++) { 332 len = (i == blocks && last) ? last : AES_BLOCK_LEN; 333 /* Decrypt, with counter */ 334 b0[14] = (i >> 8) & 0xff; 335 b0[15] = i & 0xff; 336 ieee80211_ccmp_aes_encrypt(key->tfm, b0, b); 337 xor_block(pos, b, len); 338 /* Authentication */ 339 xor_block(a, pos, len); 340 ieee80211_ccmp_aes_encrypt(key->tfm, a, a); 341 pos += len; 342 } 343 344 if (memcmp(mic, a, CCMP_MIC_LEN) != 0) { 345 if (net_ratelimit()) { 346 printk(KERN_DEBUG "CCMP: decrypt failed: STA=" 347 "%pM\n", hdr->addr2); 348 } 349 key->dot11RSNAStatsCCMPDecryptErrors++; 350 return -5; 351 } 352 353 memcpy(key->rx_pn, pn, CCMP_PN_LEN); 354 355 /* Remove hdr and MIC */ 356 memmove(skb->data + CCMP_HDR_LEN, skb->data, hdr_len); 357 skb_pull(skb, CCMP_HDR_LEN); 358 skb_trim(skb, skb->len - CCMP_MIC_LEN); 359 360 return keyidx; 361} 362 363 364static int ieee80211_ccmp_set_key(void *key, int len, u8 *seq, void *priv) 365{ 366 struct ieee80211_ccmp_data *data = priv; 367 int keyidx; 368 struct crypto_tfm *tfm = data->tfm; 369 370 keyidx = data->key_idx; 371 memset(data, 0, sizeof(*data)); 372 data->key_idx = keyidx; 373 data->tfm = tfm; 374 if (len == CCMP_TK_LEN) { 375 memcpy(data->key, key, CCMP_TK_LEN); 376 data->key_set = 1; 377 if (seq) { 378 data->rx_pn[0] = seq[5]; 379 data->rx_pn[1] = seq[4]; 380 data->rx_pn[2] = seq[3]; 381 data->rx_pn[3] = seq[2]; 382 data->rx_pn[4] = seq[1]; 383 data->rx_pn[5] = seq[0]; 384 } 385 crypto_cipher_setkey((void *)data->tfm, data->key, CCMP_TK_LEN); 386 } else if (len == 0) 387 data->key_set = 0; 388 else 389 return -1; 390 391 return 0; 392} 393 394 395static int ieee80211_ccmp_get_key(void *key, int len, u8 *seq, void *priv) 396{ 397 struct ieee80211_ccmp_data *data = priv; 398 399 if (len < CCMP_TK_LEN) 400 return -1; 401 402 if (!data->key_set) 403 return 0; 404 memcpy(key, data->key, CCMP_TK_LEN); 405 406 if (seq) { 407 seq[0] = data->tx_pn[5]; 408 seq[1] = data->tx_pn[4]; 409 seq[2] = data->tx_pn[3]; 410 seq[3] = data->tx_pn[2]; 411 seq[4] = data->tx_pn[1]; 412 seq[5] = data->tx_pn[0]; 413 } 414 415 return CCMP_TK_LEN; 416} 417 418 419static char * ieee80211_ccmp_print_stats(char *p, void *priv) 420{ 421 struct ieee80211_ccmp_data *ccmp = priv; 422 p += sprintf(p, "key[%d] alg=CCMP key_set=%d " 423 "tx_pn=%pm rx_pn=%pm " 424 "format_errors=%d replays=%d decrypt_errors=%d\n", 425 ccmp->key_idx, ccmp->key_set, 426 ccmp->tx_pn, ccmp->rx_pn, 427 ccmp->dot11RSNAStatsCCMPFormatErrors, 428 ccmp->dot11RSNAStatsCCMPReplays, 429 ccmp->dot11RSNAStatsCCMPDecryptErrors); 430 431 return p; 432} 433 434void ieee80211_ccmp_null(void) 435{ 436// printk("============>%s()\n", __func__); 437 return; 438} 439static struct ieee80211_crypto_ops ieee80211_crypt_ccmp = { 440 .name = "CCMP", 441 .init = ieee80211_ccmp_init, 442 .deinit = ieee80211_ccmp_deinit, 443 .encrypt_mpdu = ieee80211_ccmp_encrypt, 444 .decrypt_mpdu = ieee80211_ccmp_decrypt, 445 .encrypt_msdu = NULL, 446 .decrypt_msdu = NULL, 447 .set_key = ieee80211_ccmp_set_key, 448 .get_key = ieee80211_ccmp_get_key, 449 .print_stats = ieee80211_ccmp_print_stats, 450 .extra_prefix_len = CCMP_HDR_LEN, 451 .extra_postfix_len = CCMP_MIC_LEN, 452 .owner = THIS_MODULE, 453}; 454 455 456int ieee80211_crypto_ccmp_init(void) 457{ 458 return ieee80211_register_crypto_ops(&ieee80211_crypt_ccmp); 459} 460 461 462void ieee80211_crypto_ccmp_exit(void) 463{ 464 ieee80211_unregister_crypto_ops(&ieee80211_crypt_ccmp); 465} 466