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#define AES_BLOCK_LEN 16 35#define CCMP_HDR_LEN 8 36#define CCMP_MIC_LEN 8 37#define CCMP_TK_LEN 16 38#define CCMP_PN_LEN 6 39 40struct ieee80211_ccmp_data { 41 u8 key[CCMP_TK_LEN]; 42 int key_set; 43 44 u8 tx_pn[CCMP_PN_LEN]; 45 u8 rx_pn[CCMP_PN_LEN]; 46 47 u32 dot11RSNAStatsCCMPFormatErrors; 48 u32 dot11RSNAStatsCCMPReplays; 49 u32 dot11RSNAStatsCCMPDecryptErrors; 50 51 int key_idx; 52 53 struct crypto_tfm *tfm; 54 55 /* scratch buffers for virt_to_page() (crypto API) */ 56 u8 tx_b0[AES_BLOCK_LEN], tx_b[AES_BLOCK_LEN], 57 tx_e[AES_BLOCK_LEN], tx_s0[AES_BLOCK_LEN]; 58 u8 rx_b0[AES_BLOCK_LEN], rx_b[AES_BLOCK_LEN], rx_a[AES_BLOCK_LEN]; 59}; 60 61void ieee80211_ccmp_aes_encrypt(struct crypto_tfm *tfm, 62 const u8 pt[16], u8 ct[16]) 63{ 64 crypto_cipher_encrypt_one((void*)tfm, ct, pt); 65} 66 67static void * ieee80211_ccmp_init(int key_idx) 68{ 69 struct ieee80211_ccmp_data *priv; 70 71 priv = kzalloc(sizeof(*priv), GFP_ATOMIC); 72 if (priv == NULL) 73 goto fail; 74 priv->key_idx = key_idx; 75 76 priv->tfm = (void*)crypto_alloc_cipher("aes", 0, CRYPTO_ALG_ASYNC); 77 if (IS_ERR(priv->tfm)) { 78 printk(KERN_DEBUG "ieee80211_crypt_ccmp: could not allocate " 79 "crypto API aes\n"); 80 priv->tfm = NULL; 81 goto fail; 82 } 83 84 return priv; 85 86fail: 87 if (priv) { 88 if (priv->tfm) 89 crypto_free_cipher((void*)priv->tfm); 90 kfree(priv); 91 } 92 93 return NULL; 94} 95 96 97static void ieee80211_ccmp_deinit(void *priv) 98{ 99 struct ieee80211_ccmp_data *_priv = priv; 100 101 if (_priv && _priv->tfm) 102 crypto_free_cipher((void*)_priv->tfm); 103 kfree(priv); 104} 105 106 107static inline void xor_block(u8 *b, u8 *a, size_t len) 108{ 109 int i; 110 for (i = 0; i < len; i++) 111 b[i] ^= a[i]; 112} 113 114 115 116static void ccmp_init_blocks(struct crypto_tfm *tfm, 117 struct ieee80211_hdr_4addr *hdr, 118 u8 *pn, size_t dlen, u8 *b0, u8 *auth, 119 u8 *s0) 120{ 121 u8 *pos, qc = 0; 122 size_t aad_len; 123 u16 fc; 124 int a4_included, qc_included; 125 u8 aad[2 * AES_BLOCK_LEN]; 126 127 fc = le16_to_cpu(hdr->frame_ctl); 128 a4_included = ((fc & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) == 129 (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)); 130 /* 131 qc_included = ((WLAN_FC_GET_TYPE(fc) == IEEE80211_FTYPE_DATA) && 132 (WLAN_FC_GET_STYPE(fc) & 0x08)); 133 */ 134 // fixed by David :2006.9.6 135 qc_included = ((WLAN_FC_GET_TYPE(fc) == IEEE80211_FTYPE_DATA) && 136 (WLAN_FC_GET_STYPE(fc) & 0x80)); 137 aad_len = 22; 138 if (a4_included) 139 aad_len += 6; 140 if (qc_included) { 141 pos = (u8 *) &hdr->addr4; 142 if (a4_included) 143 pos += 6; 144 qc = *pos & 0x0f; 145 aad_len += 2; 146 } 147 /* CCM Initial Block: 148 * Flag (Include authentication header, M=3 (8-octet MIC), 149 * L=1 (2-octet Dlen)) 150 * Nonce: 0x00 | A2 | PN 151 * Dlen */ 152 b0[0] = 0x59; 153 b0[1] = qc; 154 memcpy(b0 + 2, hdr->addr2, ETH_ALEN); 155 memcpy(b0 + 8, pn, CCMP_PN_LEN); 156 b0[14] = (dlen >> 8) & 0xff; 157 b0[15] = dlen & 0xff; 158 159 /* AAD: 160 * FC with bits 4..6 and 11..13 masked to zero; 14 is always one 161 * A1 | A2 | A3 162 * SC with bits 4..15 (seq#) masked to zero 163 * A4 (if present) 164 * QC (if present) 165 */ 166 pos = (u8 *) hdr; 167 aad[0] = 0; /* aad_len >> 8 */ 168 aad[1] = aad_len & 0xff; 169 aad[2] = pos[0] & 0x8f; 170 aad[3] = pos[1] & 0xc7; 171 memcpy(aad + 4, hdr->addr1, 3 * ETH_ALEN); 172 pos = (u8 *) &hdr->seq_ctl; 173 aad[22] = pos[0] & 0x0f; 174 aad[23] = 0; /* all bits masked */ 175 memset(aad + 24, 0, 8); 176 if (a4_included) 177 memcpy(aad + 24, hdr->addr4, ETH_ALEN); 178 if (qc_included) { 179 aad[a4_included ? 30 : 24] = qc; 180 /* rest of QC masked */ 181 } 182 183 /* Start with the first block and AAD */ 184 ieee80211_ccmp_aes_encrypt(tfm, b0, auth); 185 xor_block(auth, aad, AES_BLOCK_LEN); 186 ieee80211_ccmp_aes_encrypt(tfm, auth, auth); 187 xor_block(auth, &aad[AES_BLOCK_LEN], AES_BLOCK_LEN); 188 ieee80211_ccmp_aes_encrypt(tfm, auth, auth); 189 b0[0] &= 0x07; 190 b0[14] = b0[15] = 0; 191 ieee80211_ccmp_aes_encrypt(tfm, b0, s0); 192} 193 194 195 196static int ieee80211_ccmp_encrypt(struct sk_buff *skb, int hdr_len, void *priv) 197{ 198 struct ieee80211_ccmp_data *key = priv; 199 int data_len, i; 200 u8 *pos; 201 struct ieee80211_hdr_4addr *hdr; 202 cb_desc *tcb_desc = (cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE); 203 204 if (skb_headroom(skb) < CCMP_HDR_LEN || 205 skb_tailroom(skb) < CCMP_MIC_LEN || 206 skb->len < hdr_len) 207 return -1; 208 209 data_len = skb->len - hdr_len; 210 pos = skb_push(skb, CCMP_HDR_LEN); 211 memmove(pos, pos + CCMP_HDR_LEN, hdr_len); 212 pos += hdr_len; 213// mic = skb_put(skb, CCMP_MIC_LEN); 214 215 i = CCMP_PN_LEN - 1; 216 while (i >= 0) { 217 key->tx_pn[i]++; 218 if (key->tx_pn[i] != 0) 219 break; 220 i--; 221 } 222 223 *pos++ = key->tx_pn[5]; 224 *pos++ = key->tx_pn[4]; 225 *pos++ = 0; 226 *pos++ = (key->key_idx << 6) | (1 << 5) /* Ext IV included */; 227 *pos++ = key->tx_pn[3]; 228 *pos++ = key->tx_pn[2]; 229 *pos++ = key->tx_pn[1]; 230 *pos++ = key->tx_pn[0]; 231 232 233 hdr = (struct ieee80211_hdr_4addr *) skb->data; 234 if (!tcb_desc->bHwSec) 235 { 236 int blocks, last, len; 237 u8 *mic; 238 u8 *b0 = key->tx_b0; 239 u8 *b = key->tx_b; 240 u8 *e = key->tx_e; 241 u8 *s0 = key->tx_s0; 242 243 //mic is moved to here by john 244 mic = skb_put(skb, CCMP_MIC_LEN); 245 246 ccmp_init_blocks(key->tfm, hdr, key->tx_pn, data_len, b0, b, s0); 247 248 blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN; 249 last = data_len % AES_BLOCK_LEN; 250 251 for (i = 1; i <= blocks; i++) { 252 len = (i == blocks && last) ? last : AES_BLOCK_LEN; 253 /* Authentication */ 254 xor_block(b, pos, len); 255 ieee80211_ccmp_aes_encrypt(key->tfm, b, b); 256 /* Encryption, with counter */ 257 b0[14] = (i >> 8) & 0xff; 258 b0[15] = i & 0xff; 259 ieee80211_ccmp_aes_encrypt(key->tfm, b0, e); 260 xor_block(pos, e, len); 261 pos += len; 262 } 263 264 for (i = 0; i < CCMP_MIC_LEN; i++) 265 mic[i] = b[i] ^ s0[i]; 266 } 267 return 0; 268} 269 270 271static int ieee80211_ccmp_decrypt(struct sk_buff *skb, int hdr_len, void *priv) 272{ 273 struct ieee80211_ccmp_data *key = priv; 274 u8 keyidx, *pos; 275 struct ieee80211_hdr_4addr *hdr; 276 cb_desc *tcb_desc = (cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE); 277 u8 pn[6]; 278 279 if (skb->len < hdr_len + CCMP_HDR_LEN + CCMP_MIC_LEN) { 280 key->dot11RSNAStatsCCMPFormatErrors++; 281 return -1; 282 } 283 284 hdr = (struct ieee80211_hdr_4addr *) skb->data; 285 pos = skb->data + hdr_len; 286 keyidx = pos[3]; 287 if (!(keyidx & (1 << 5))) { 288 if (net_ratelimit()) { 289 printk(KERN_DEBUG "CCMP: received packet without ExtIV" 290 " flag from %pM\n", hdr->addr2); 291 } 292 key->dot11RSNAStatsCCMPFormatErrors++; 293 return -2; 294 } 295 keyidx >>= 6; 296 if (key->key_idx != keyidx) { 297 printk(KERN_DEBUG "CCMP: RX tkey->key_idx=%d frame " 298 "keyidx=%d priv=%p\n", key->key_idx, keyidx, priv); 299 return -6; 300 } 301 if (!key->key_set) { 302 if (net_ratelimit()) { 303 printk(KERN_DEBUG "CCMP: received packet from %pM" 304 " with keyid=%d that does not have a configured" 305 " key\n", hdr->addr2, keyidx); 306 } 307 return -3; 308 } 309 310 pn[0] = pos[7]; 311 pn[1] = pos[6]; 312 pn[2] = pos[5]; 313 pn[3] = pos[4]; 314 pn[4] = pos[1]; 315 pn[5] = pos[0]; 316 pos += 8; 317 318 if (memcmp(pn, key->rx_pn, CCMP_PN_LEN) <= 0) { 319 if (net_ratelimit()) { 320 printk(KERN_DEBUG "CCMP: replay detected: STA=%pM" 321 " previous PN %pm received PN %pm\n", 322 hdr->addr2, key->rx_pn, pn); 323 } 324 key->dot11RSNAStatsCCMPReplays++; 325 return -4; 326 } 327 if (!tcb_desc->bHwSec) 328 { 329 size_t data_len = skb->len - hdr_len - CCMP_HDR_LEN - CCMP_MIC_LEN; 330 u8 *mic = skb->data + skb->len - CCMP_MIC_LEN; 331 u8 *b0 = key->rx_b0; 332 u8 *b = key->rx_b; 333 u8 *a = key->rx_a; 334 int i, blocks, last, len; 335 336 337 ccmp_init_blocks(key->tfm, hdr, pn, data_len, b0, a, b); 338 xor_block(mic, b, CCMP_MIC_LEN); 339 340 blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN; 341 last = data_len % AES_BLOCK_LEN; 342 343 for (i = 1; i <= blocks; i++) { 344 len = (i == blocks && last) ? last : AES_BLOCK_LEN; 345 /* Decrypt, with counter */ 346 b0[14] = (i >> 8) & 0xff; 347 b0[15] = i & 0xff; 348 ieee80211_ccmp_aes_encrypt(key->tfm, b0, b); 349 xor_block(pos, b, len); 350 /* Authentication */ 351 xor_block(a, pos, len); 352 ieee80211_ccmp_aes_encrypt(key->tfm, a, a); 353 pos += len; 354 } 355 356 if (memcmp(mic, a, CCMP_MIC_LEN) != 0) { 357 if (net_ratelimit()) { 358 printk(KERN_DEBUG "CCMP: decrypt failed: STA=" 359 "%pM\n", hdr->addr2); 360 } 361 key->dot11RSNAStatsCCMPDecryptErrors++; 362 return -5; 363 } 364 365 memcpy(key->rx_pn, pn, CCMP_PN_LEN); 366 } 367 /* Remove hdr and MIC */ 368 memmove(skb->data + CCMP_HDR_LEN, skb->data, hdr_len); 369 skb_pull(skb, CCMP_HDR_LEN); 370 skb_trim(skb, skb->len - CCMP_MIC_LEN); 371 372 return keyidx; 373} 374 375 376static int ieee80211_ccmp_set_key(void *key, int len, u8 *seq, void *priv) 377{ 378 struct ieee80211_ccmp_data *data = priv; 379 int keyidx; 380 struct crypto_tfm *tfm = data->tfm; 381 382 keyidx = data->key_idx; 383 memset(data, 0, sizeof(*data)); 384 data->key_idx = keyidx; 385 data->tfm = tfm; 386 if (len == CCMP_TK_LEN) { 387 memcpy(data->key, key, CCMP_TK_LEN); 388 data->key_set = 1; 389 if (seq) { 390 data->rx_pn[0] = seq[5]; 391 data->rx_pn[1] = seq[4]; 392 data->rx_pn[2] = seq[3]; 393 data->rx_pn[3] = seq[2]; 394 data->rx_pn[4] = seq[1]; 395 data->rx_pn[5] = seq[0]; 396 } 397 crypto_cipher_setkey((void*)data->tfm, data->key, CCMP_TK_LEN); 398 } else if (len == 0) 399 data->key_set = 0; 400 else 401 return -1; 402 403 return 0; 404} 405 406 407static int ieee80211_ccmp_get_key(void *key, int len, u8 *seq, void *priv) 408{ 409 struct ieee80211_ccmp_data *data = priv; 410 411 if (len < CCMP_TK_LEN) 412 return -1; 413 414 if (!data->key_set) 415 return 0; 416 memcpy(key, data->key, CCMP_TK_LEN); 417 418 if (seq) { 419 seq[0] = data->tx_pn[5]; 420 seq[1] = data->tx_pn[4]; 421 seq[2] = data->tx_pn[3]; 422 seq[3] = data->tx_pn[2]; 423 seq[4] = data->tx_pn[1]; 424 seq[5] = data->tx_pn[0]; 425 } 426 427 return CCMP_TK_LEN; 428} 429 430 431static char * ieee80211_ccmp_print_stats(char *p, void *priv) 432{ 433 struct ieee80211_ccmp_data *ccmp = priv; 434 p += sprintf(p, "key[%d] alg=CCMP key_set=%d " 435 "tx_pn=%pm rx_pn=%pm " 436 "format_errors=%d replays=%d decrypt_errors=%d\n", 437 ccmp->key_idx, ccmp->key_set, 438 ccmp->tx_pn, ccmp->rx_pn, 439 ccmp->dot11RSNAStatsCCMPFormatErrors, 440 ccmp->dot11RSNAStatsCCMPReplays, 441 ccmp->dot11RSNAStatsCCMPDecryptErrors); 442 443 return p; 444} 445 446void ieee80211_ccmp_null(void) 447{ 448// printk("============>%s()\n", __FUNCTION__); 449 return; 450} 451 452static struct ieee80211_crypto_ops ieee80211_crypt_ccmp = { 453 .name = "CCMP", 454 .init = ieee80211_ccmp_init, 455 .deinit = ieee80211_ccmp_deinit, 456 .encrypt_mpdu = ieee80211_ccmp_encrypt, 457 .decrypt_mpdu = ieee80211_ccmp_decrypt, 458 .encrypt_msdu = NULL, 459 .decrypt_msdu = NULL, 460 .set_key = ieee80211_ccmp_set_key, 461 .get_key = ieee80211_ccmp_get_key, 462 .print_stats = ieee80211_ccmp_print_stats, 463 .extra_prefix_len = CCMP_HDR_LEN, 464 .extra_postfix_len = CCMP_MIC_LEN, 465 .owner = THIS_MODULE, 466}; 467 468int __init ieee80211_crypto_ccmp_init(void) 469{ 470 return ieee80211_register_crypto_ops(&ieee80211_crypt_ccmp); 471} 472 473void __exit ieee80211_crypto_ccmp_exit(void) 474{ 475 ieee80211_unregister_crypto_ops(&ieee80211_crypt_ccmp); 476} 477