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/module.h> 14#include <linux/init.h> 15#include <linux/slab.h> 16#include <linux/random.h> 17#include <linux/skbuff.h> 18#include <linux/netdevice.h> 19#include <linux/if_ether.h> 20#include <linux/if_arp.h> 21#include <asm/string.h> 22#include <linux/wireless.h> 23 24#include "ieee80211.h" 25 26#include <linux/crypto.h> 27 #include <linux/scatterlist.h> 28 29MODULE_AUTHOR("Jouni Malinen"); 30MODULE_DESCRIPTION("Host AP crypt: CCMP"); 31MODULE_LICENSE("GPL"); 32 33#define AES_BLOCK_LEN 16 34#define CCMP_HDR_LEN 8 35#define CCMP_MIC_LEN 8 36#define CCMP_TK_LEN 16 37#define CCMP_PN_LEN 6 38 39struct ieee80211_ccmp_data { 40 u8 key[CCMP_TK_LEN]; 41 int key_set; 42 43 u8 tx_pn[CCMP_PN_LEN]; 44 u8 rx_pn[CCMP_PN_LEN]; 45 46 u32 dot11RSNAStatsCCMPFormatErrors; 47 u32 dot11RSNAStatsCCMPReplays; 48 u32 dot11RSNAStatsCCMPDecryptErrors; 49 50 int key_idx; 51 52 struct crypto_tfm *tfm; 53 54 /* scratch buffers for virt_to_page() (crypto API) */ 55 u8 tx_b0[AES_BLOCK_LEN], tx_b[AES_BLOCK_LEN], 56 tx_e[AES_BLOCK_LEN], tx_s0[AES_BLOCK_LEN]; 57 u8 rx_b0[AES_BLOCK_LEN], rx_b[AES_BLOCK_LEN], rx_a[AES_BLOCK_LEN]; 58}; 59 60static void ieee80211_ccmp_aes_encrypt(struct crypto_tfm *tfm, 61 const u8 pt[16], u8 ct[16]) 62{ 63 crypto_cipher_encrypt_one((void *)tfm, ct, pt); 64} 65 66static void *ieee80211_ccmp_init(int key_idx) 67{ 68 struct ieee80211_ccmp_data *priv; 69 70 priv = kzalloc(sizeof(*priv), GFP_ATOMIC); 71 if (priv == NULL) 72 goto fail; 73 priv->key_idx = key_idx; 74 75 priv->tfm = (void *)crypto_alloc_cipher("aes", 0, CRYPTO_ALG_ASYNC); 76 if (IS_ERR(priv->tfm)) { 77 printk(KERN_DEBUG "ieee80211_crypt_ccmp: could not allocate " 78 "crypto API aes\n"); 79 priv->tfm = NULL; 80 goto fail; 81 } 82 83 return priv; 84 85fail: 86 if (priv) { 87 if (priv->tfm) 88 crypto_free_cipher((void *)priv->tfm); 89 kfree(priv); 90 } 91 92 return NULL; 93} 94 95 96static void ieee80211_ccmp_deinit(void *priv) 97{ 98 struct ieee80211_ccmp_data *_priv = priv; 99 100 if (_priv && _priv->tfm) 101 crypto_free_cipher((void *)_priv->tfm); 102 kfree(priv); 103} 104 105 106static inline void xor_block(u8 *b, u8 *a, size_t len) 107{ 108 int i; 109 for (i = 0; i < len; i++) 110 b[i] ^= a[i]; 111} 112 113 114 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} 192 193 194 195static int ieee80211_ccmp_encrypt(struct sk_buff *skb, int hdr_len, void *priv) 196{ 197 struct ieee80211_ccmp_data *key = priv; 198 int data_len, i; 199 u8 *pos; 200 struct ieee80211_hdr_4addr *hdr; 201 cb_desc *tcb_desc = (cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE); 202 203 if (skb_headroom(skb) < CCMP_HDR_LEN || 204 skb_tailroom(skb) < CCMP_MIC_LEN || 205 skb->len < hdr_len) 206 return -1; 207 208 data_len = skb->len - hdr_len; 209 pos = skb_push(skb, CCMP_HDR_LEN); 210 memmove(pos, pos + CCMP_HDR_LEN, hdr_len); 211 pos += hdr_len; 212// mic = skb_put(skb, CCMP_MIC_LEN); 213 214 i = CCMP_PN_LEN - 1; 215 while (i >= 0) { 216 key->tx_pn[i]++; 217 if (key->tx_pn[i] != 0) 218 break; 219 i--; 220 } 221 222 *pos++ = key->tx_pn[5]; 223 *pos++ = key->tx_pn[4]; 224 *pos++ = 0; 225 *pos++ = (key->key_idx << 6) | (1 << 5) /* Ext IV included */; 226 *pos++ = key->tx_pn[3]; 227 *pos++ = key->tx_pn[2]; 228 *pos++ = key->tx_pn[1]; 229 *pos++ = key->tx_pn[0]; 230 231 232 hdr = (struct ieee80211_hdr_4addr *) skb->data; 233 if (!tcb_desc->bHwSec) 234 { 235 int blocks, last, len; 236 u8 *mic; 237 u8 *b0 = key->tx_b0; 238 u8 *b = key->tx_b; 239 u8 *e = key->tx_e; 240 u8 *s0 = key->tx_s0; 241 242 //mic is moved to here by john 243 mic = skb_put(skb, CCMP_MIC_LEN); 244 245 ccmp_init_blocks(key->tfm, hdr, key->tx_pn, data_len, b0, b, s0); 246 247 blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN; 248 last = data_len % AES_BLOCK_LEN; 249 250 for (i = 1; i <= blocks; i++) { 251 len = (i == blocks && last) ? last : AES_BLOCK_LEN; 252 /* Authentication */ 253 xor_block(b, pos, len); 254 ieee80211_ccmp_aes_encrypt(key->tfm, b, b); 255 /* Encryption, with counter */ 256 b0[14] = (i >> 8) & 0xff; 257 b0[15] = i & 0xff; 258 ieee80211_ccmp_aes_encrypt(key->tfm, b0, e); 259 xor_block(pos, e, len); 260 pos += len; 261 } 262 263 for (i = 0; i < CCMP_MIC_LEN; i++) 264 mic[i] = b[i] ^ s0[i]; 265 } 266 return 0; 267} 268 269 270static int ieee80211_ccmp_decrypt(struct sk_buff *skb, int hdr_len, void *priv) 271{ 272 struct ieee80211_ccmp_data *key = priv; 273 u8 keyidx, *pos; 274 struct ieee80211_hdr_4addr *hdr; 275 cb_desc *tcb_desc = (cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE); 276 u8 pn[6]; 277 278 if (skb->len < hdr_len + CCMP_HDR_LEN + CCMP_MIC_LEN) { 279 key->dot11RSNAStatsCCMPFormatErrors++; 280 return -1; 281 } 282 283 hdr = (struct ieee80211_hdr_4addr *) skb->data; 284 pos = skb->data + hdr_len; 285 keyidx = pos[3]; 286 if (!(keyidx & (1 << 5))) { 287 if (net_ratelimit()) { 288 printk(KERN_DEBUG "CCMP: received packet without ExtIV" 289 " flag from %pM\n", hdr->addr2); 290 } 291 key->dot11RSNAStatsCCMPFormatErrors++; 292 return -2; 293 } 294 keyidx >>= 6; 295 if (key->key_idx != keyidx) { 296 printk(KERN_DEBUG "CCMP: RX tkey->key_idx=%d frame " 297 "keyidx=%d priv=%p\n", key->key_idx, keyidx, priv); 298 return -6; 299 } 300 if (!key->key_set) { 301 if (net_ratelimit()) { 302 printk(KERN_DEBUG "CCMP: received packet from %pM" 303 " with keyid=%d that does not have a configured" 304 " key\n", hdr->addr2, keyidx); 305 } 306 return -3; 307 } 308 309 pn[0] = pos[7]; 310 pn[1] = pos[6]; 311 pn[2] = pos[5]; 312 pn[3] = pos[4]; 313 pn[4] = pos[1]; 314 pn[5] = pos[0]; 315 pos += 8; 316 317 if (memcmp(pn, key->rx_pn, CCMP_PN_LEN) <= 0) { 318 if (net_ratelimit()) { 319 printk(KERN_DEBUG "CCMP: replay detected: STA=%pM" 320 " previous PN %pm received PN %pm\n", 321 hdr->addr2, key->rx_pn, pn); 322 } 323 key->dot11RSNAStatsCCMPReplays++; 324 return -4; 325 } 326 if (!tcb_desc->bHwSec) 327 { 328 size_t data_len = skb->len - hdr_len - CCMP_HDR_LEN - CCMP_MIC_LEN; 329 u8 *mic = skb->data + skb->len - CCMP_MIC_LEN; 330 u8 *b0 = key->rx_b0; 331 u8 *b = key->rx_b; 332 u8 *a = key->rx_a; 333 int i, blocks, last, len; 334 335 336 ccmp_init_blocks(key->tfm, hdr, pn, data_len, b0, a, b); 337 xor_block(mic, b, CCMP_MIC_LEN); 338 339 blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN; 340 last = data_len % AES_BLOCK_LEN; 341 342 for (i = 1; i <= blocks; i++) { 343 len = (i == blocks && last) ? last : AES_BLOCK_LEN; 344 /* Decrypt, with counter */ 345 b0[14] = (i >> 8) & 0xff; 346 b0[15] = i & 0xff; 347 ieee80211_ccmp_aes_encrypt(key->tfm, b0, b); 348 xor_block(pos, b, len); 349 /* Authentication */ 350 xor_block(a, pos, len); 351 ieee80211_ccmp_aes_encrypt(key->tfm, a, a); 352 pos += len; 353 } 354 355 if (memcmp(mic, a, CCMP_MIC_LEN) != 0) { 356 if (net_ratelimit()) { 357 printk(KERN_DEBUG "CCMP: decrypt failed: STA=" 358 "%pM\n", hdr->addr2); 359 } 360 key->dot11RSNAStatsCCMPDecryptErrors++; 361 return -5; 362 } 363 364 memcpy(key->rx_pn, pn, CCMP_PN_LEN); 365 } 366 /* Remove hdr and MIC */ 367 memmove(skb->data + CCMP_HDR_LEN, skb->data, hdr_len); 368 skb_pull(skb, CCMP_HDR_LEN); 369 skb_trim(skb, skb->len - CCMP_MIC_LEN); 370 371 return keyidx; 372} 373 374 375static int ieee80211_ccmp_set_key(void *key, int len, u8 *seq, void *priv) 376{ 377 struct ieee80211_ccmp_data *data = priv; 378 int keyidx; 379 struct crypto_tfm *tfm = data->tfm; 380 381 keyidx = data->key_idx; 382 memset(data, 0, sizeof(*data)); 383 data->key_idx = keyidx; 384 data->tfm = tfm; 385 if (len == CCMP_TK_LEN) { 386 memcpy(data->key, key, CCMP_TK_LEN); 387 data->key_set = 1; 388 if (seq) { 389 data->rx_pn[0] = seq[5]; 390 data->rx_pn[1] = seq[4]; 391 data->rx_pn[2] = seq[3]; 392 data->rx_pn[3] = seq[2]; 393 data->rx_pn[4] = seq[1]; 394 data->rx_pn[5] = seq[0]; 395 } 396 crypto_cipher_setkey((void *)data->tfm, data->key, CCMP_TK_LEN); 397 } else if (len == 0) 398 data->key_set = 0; 399 else 400 return -1; 401 402 return 0; 403} 404 405 406static int ieee80211_ccmp_get_key(void *key, int len, u8 *seq, void *priv) 407{ 408 struct ieee80211_ccmp_data *data = priv; 409 410 if (len < CCMP_TK_LEN) 411 return -1; 412 413 if (!data->key_set) 414 return 0; 415 memcpy(key, data->key, CCMP_TK_LEN); 416 417 if (seq) { 418 seq[0] = data->tx_pn[5]; 419 seq[1] = data->tx_pn[4]; 420 seq[2] = data->tx_pn[3]; 421 seq[3] = data->tx_pn[2]; 422 seq[4] = data->tx_pn[1]; 423 seq[5] = data->tx_pn[0]; 424 } 425 426 return CCMP_TK_LEN; 427} 428 429 430static char *ieee80211_ccmp_print_stats(char *p, void *priv) 431{ 432 struct ieee80211_ccmp_data *ccmp = priv; 433 p += sprintf(p, "key[%d] alg=CCMP key_set=%d " 434 "tx_pn=%pm rx_pn=%pm " 435 "format_errors=%d replays=%d decrypt_errors=%d\n", 436 ccmp->key_idx, ccmp->key_set, 437 ccmp->tx_pn, ccmp->rx_pn, 438 ccmp->dot11RSNAStatsCCMPFormatErrors, 439 ccmp->dot11RSNAStatsCCMPReplays, 440 ccmp->dot11RSNAStatsCCMPDecryptErrors); 441 442 return p; 443} 444 445void ieee80211_ccmp_null(void) 446{ 447// printk("============>%s()\n", __func__); 448 return; 449} 450 451static struct ieee80211_crypto_ops ieee80211_crypt_ccmp = { 452 .name = "CCMP", 453 .init = ieee80211_ccmp_init, 454 .deinit = ieee80211_ccmp_deinit, 455 .encrypt_mpdu = ieee80211_ccmp_encrypt, 456 .decrypt_mpdu = ieee80211_ccmp_decrypt, 457 .encrypt_msdu = NULL, 458 .decrypt_msdu = NULL, 459 .set_key = ieee80211_ccmp_set_key, 460 .get_key = ieee80211_ccmp_get_key, 461 .print_stats = ieee80211_ccmp_print_stats, 462 .extra_prefix_len = CCMP_HDR_LEN, 463 .extra_postfix_len = CCMP_MIC_LEN, 464 .owner = THIS_MODULE, 465}; 466 467int __init ieee80211_crypto_ccmp_init(void) 468{ 469 return ieee80211_register_crypto_ops(&ieee80211_crypt_ccmp); 470} 471 472void __exit ieee80211_crypto_ccmp_exit(void) 473{ 474 ieee80211_unregister_crypto_ops(&ieee80211_crypt_ccmp); 475} 476