1 /* 2 * Copyright 2002-2004, Instant802 Networks, Inc. 3 * Copyright 2008, Jouni Malinen <j@w1.fi> 4 * 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License version 2 as 7 * published by the Free Software Foundation. 8 */ 9 10 #include <linux/netdevice.h> 11 #include <linux/types.h> 12 #include <linux/skbuff.h> 13 #include <linux/compiler.h> 14 #include <linux/ieee80211.h> 15 #include <linux/gfp.h> 16 #include <asm/unaligned.h> 17 #include <net/mac80211.h> 18 #include <crypto/aes.h> 19 20 #include "ieee80211_i.h" 21 #include "michael.h" 22 #include "tkip.h" 23 #include "aes_ccm.h" 24 #include "aes_cmac.h" 25 #include "wpa.h" 26 27 ieee80211_tx_result 28 ieee80211_tx_h_michael_mic_add(struct ieee80211_tx_data *tx) 29 { 30 u8 *data, *key, *mic; 31 size_t data_len; 32 unsigned int hdrlen; 33 struct ieee80211_hdr *hdr; 34 struct sk_buff *skb = tx->skb; 35 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); 36 int tail; 37 38 hdr = (struct ieee80211_hdr *)skb->data; 39 if (!tx->key || tx->key->conf.cipher != WLAN_CIPHER_SUITE_TKIP || 40 skb->len < 24 || !ieee80211_is_data_present(hdr->frame_control)) 41 return TX_CONTINUE; 42 43 hdrlen = ieee80211_hdrlen(hdr->frame_control); 44 if (skb->len < hdrlen) 45 return TX_DROP; 46 47 data = skb->data + hdrlen; 48 data_len = skb->len - hdrlen; 49 50 if (unlikely(info->flags & IEEE80211_TX_INTFL_TKIP_MIC_FAILURE)) { 51 /* Need to use software crypto for the test */ 52 info->control.hw_key = NULL; 53 } 54 55 if (info->control.hw_key && 56 (info->flags & IEEE80211_TX_CTL_DONTFRAG || 57 tx->local->ops->set_frag_threshold) && 58 !(tx->key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_MMIC)) { 59 /* hwaccel - with no need for SW-generated MMIC */ 60 return TX_CONTINUE; 61 } 62 63 tail = MICHAEL_MIC_LEN; 64 if (!info->control.hw_key) 65 tail += IEEE80211_TKIP_ICV_LEN; 66 67 if (WARN_ON(skb_tailroom(skb) < tail || 68 skb_headroom(skb) < IEEE80211_TKIP_IV_LEN)) 69 return TX_DROP; 70 71 key = &tx->key->conf.key[NL80211_TKIP_DATA_OFFSET_TX_MIC_KEY]; 72 mic = skb_put(skb, MICHAEL_MIC_LEN); 73 michael_mic(key, hdr, data, data_len, mic); 74 if (unlikely(info->flags & IEEE80211_TX_INTFL_TKIP_MIC_FAILURE)) 75 mic[0]++; 76 77 return TX_CONTINUE; 78 } 79 80 81 ieee80211_rx_result 82 ieee80211_rx_h_michael_mic_verify(struct ieee80211_rx_data *rx) 83 { 84 u8 *data, *key = NULL; 85 size_t data_len; 86 unsigned int hdrlen; 87 u8 mic[MICHAEL_MIC_LEN]; 88 struct sk_buff *skb = rx->skb; 89 struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb); 90 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data; 91 92 /* 93 * it makes no sense to check for MIC errors on anything other 94 * than data frames. 95 */ 96 if (!ieee80211_is_data_present(hdr->frame_control)) 97 return RX_CONTINUE; 98 99 /* 100 * No way to verify the MIC if the hardware stripped it or 101 * the IV with the key index. In this case we have solely rely 102 * on the driver to set RX_FLAG_MMIC_ERROR in the event of a 103 * MIC failure report. 104 */ 105 if (status->flag & (RX_FLAG_MMIC_STRIPPED | RX_FLAG_IV_STRIPPED)) { 106 if (status->flag & RX_FLAG_MMIC_ERROR) 107 goto mic_fail_no_key; 108 109 if (!(status->flag & RX_FLAG_IV_STRIPPED) && rx->key && 110 rx->key->conf.cipher == WLAN_CIPHER_SUITE_TKIP) 111 goto update_iv; 112 113 return RX_CONTINUE; 114 } 115 116 /* 117 * Some hardware seems to generate Michael MIC failure reports; even 118 * though, the frame was not encrypted with TKIP and therefore has no 119 * MIC. Ignore the flag them to avoid triggering countermeasures. 120 */ 121 if (!rx->key || rx->key->conf.cipher != WLAN_CIPHER_SUITE_TKIP || 122 !(status->flag & RX_FLAG_DECRYPTED)) 123 return RX_CONTINUE; 124 125 if (rx->sdata->vif.type == NL80211_IFTYPE_AP && rx->key->conf.keyidx) { 126 /* 127 * APs with pairwise keys should never receive Michael MIC 128 * errors for non-zero keyidx because these are reserved for 129 * group keys and only the AP is sending real multicast 130 * frames in the BSS. 131 */ 132 return RX_DROP_UNUSABLE; 133 } 134 135 if (status->flag & RX_FLAG_MMIC_ERROR) 136 goto mic_fail; 137 138 hdrlen = ieee80211_hdrlen(hdr->frame_control); 139 if (skb->len < hdrlen + MICHAEL_MIC_LEN) 140 return RX_DROP_UNUSABLE; 141 142 if (skb_linearize(rx->skb)) 143 return RX_DROP_UNUSABLE; 144 hdr = (void *)skb->data; 145 146 data = skb->data + hdrlen; 147 data_len = skb->len - hdrlen - MICHAEL_MIC_LEN; 148 key = &rx->key->conf.key[NL80211_TKIP_DATA_OFFSET_RX_MIC_KEY]; 149 michael_mic(key, hdr, data, data_len, mic); 150 if (memcmp(mic, data + data_len, MICHAEL_MIC_LEN) != 0) 151 goto mic_fail; 152 153 /* remove Michael MIC from payload */ 154 skb_trim(skb, skb->len - MICHAEL_MIC_LEN); 155 156 update_iv: 157 /* update IV in key information to be able to detect replays */ 158 rx->key->u.tkip.rx[rx->security_idx].iv32 = rx->tkip_iv32; 159 rx->key->u.tkip.rx[rx->security_idx].iv16 = rx->tkip_iv16; 160 161 return RX_CONTINUE; 162 163 mic_fail: 164 rx->key->u.tkip.mic_failures++; 165 166 mic_fail_no_key: 167 /* 168 * In some cases the key can be unset - e.g. a multicast packet, in 169 * a driver that supports HW encryption. Send up the key idx only if 170 * the key is set. 171 */ 172 mac80211_ev_michael_mic_failure(rx->sdata, 173 rx->key ? rx->key->conf.keyidx : -1, 174 (void *) skb->data, NULL, GFP_ATOMIC); 175 return RX_DROP_UNUSABLE; 176 } 177 178 179 static int tkip_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb) 180 { 181 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; 182 struct ieee80211_key *key = tx->key; 183 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); 184 unsigned int hdrlen; 185 int len, tail; 186 u8 *pos; 187 188 if (info->control.hw_key && 189 !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV) && 190 !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)) { 191 /* hwaccel - with no need for software-generated IV */ 192 return 0; 193 } 194 195 hdrlen = ieee80211_hdrlen(hdr->frame_control); 196 len = skb->len - hdrlen; 197 198 if (info->control.hw_key) 199 tail = 0; 200 else 201 tail = IEEE80211_TKIP_ICV_LEN; 202 203 if (WARN_ON(skb_tailroom(skb) < tail || 204 skb_headroom(skb) < IEEE80211_TKIP_IV_LEN)) 205 return -1; 206 207 pos = skb_push(skb, IEEE80211_TKIP_IV_LEN); 208 memmove(pos, pos + IEEE80211_TKIP_IV_LEN, hdrlen); 209 skb_set_network_header(skb, skb_network_offset(skb) + 210 IEEE80211_TKIP_IV_LEN); 211 pos += hdrlen; 212 213 /* the HW only needs room for the IV, but not the actual IV */ 214 if (info->control.hw_key && 215 (info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)) 216 return 0; 217 218 /* Increase IV for the frame */ 219 spin_lock(&key->u.tkip.txlock); 220 key->u.tkip.tx.iv16++; 221 if (key->u.tkip.tx.iv16 == 0) 222 key->u.tkip.tx.iv32++; 223 pos = ieee80211_tkip_add_iv(pos, key); 224 spin_unlock(&key->u.tkip.txlock); 225 226 /* hwaccel - with software IV */ 227 if (info->control.hw_key) 228 return 0; 229 230 /* Add room for ICV */ 231 skb_put(skb, IEEE80211_TKIP_ICV_LEN); 232 233 return ieee80211_tkip_encrypt_data(tx->local->wep_tx_tfm, 234 key, skb, pos, len); 235 } 236 237 238 ieee80211_tx_result 239 ieee80211_crypto_tkip_encrypt(struct ieee80211_tx_data *tx) 240 { 241 struct sk_buff *skb; 242 243 ieee80211_tx_set_protected(tx); 244 245 skb_queue_walk(&tx->skbs, skb) { 246 if (tkip_encrypt_skb(tx, skb) < 0) 247 return TX_DROP; 248 } 249 250 return TX_CONTINUE; 251 } 252 253 254 ieee80211_rx_result 255 ieee80211_crypto_tkip_decrypt(struct ieee80211_rx_data *rx) 256 { 257 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) rx->skb->data; 258 int hdrlen, res, hwaccel = 0; 259 struct ieee80211_key *key = rx->key; 260 struct sk_buff *skb = rx->skb; 261 struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb); 262 263 hdrlen = ieee80211_hdrlen(hdr->frame_control); 264 265 if (!ieee80211_is_data(hdr->frame_control)) 266 return RX_CONTINUE; 267 268 if (!rx->sta || skb->len - hdrlen < 12) 269 return RX_DROP_UNUSABLE; 270 271 /* it may be possible to optimize this a bit more */ 272 if (skb_linearize(rx->skb)) 273 return RX_DROP_UNUSABLE; 274 hdr = (void *)skb->data; 275 276 /* 277 * Let TKIP code verify IV, but skip decryption. 278 * In the case where hardware checks the IV as well, 279 * we don't even get here, see ieee80211_rx_h_decrypt() 280 */ 281 if (status->flag & RX_FLAG_DECRYPTED) 282 hwaccel = 1; 283 284 res = ieee80211_tkip_decrypt_data(rx->local->wep_rx_tfm, 285 key, skb->data + hdrlen, 286 skb->len - hdrlen, rx->sta->sta.addr, 287 hdr->addr1, hwaccel, rx->security_idx, 288 &rx->tkip_iv32, 289 &rx->tkip_iv16); 290 if (res != TKIP_DECRYPT_OK) 291 return RX_DROP_UNUSABLE; 292 293 /* Trim ICV */ 294 skb_trim(skb, skb->len - IEEE80211_TKIP_ICV_LEN); 295 296 /* Remove IV */ 297 memmove(skb->data + IEEE80211_TKIP_IV_LEN, skb->data, hdrlen); 298 skb_pull(skb, IEEE80211_TKIP_IV_LEN); 299 300 return RX_CONTINUE; 301 } 302 303 304 static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *b_0, u8 *aad) 305 { 306 __le16 mask_fc; 307 int a4_included, mgmt; 308 u8 qos_tid; 309 u16 len_a; 310 unsigned int hdrlen; 311 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data; 312 313 /* 314 * Mask FC: zero subtype b4 b5 b6 (if not mgmt) 315 * Retry, PwrMgt, MoreData; set Protected 316 */ 317 mgmt = ieee80211_is_mgmt(hdr->frame_control); 318 mask_fc = hdr->frame_control; 319 mask_fc &= ~cpu_to_le16(IEEE80211_FCTL_RETRY | 320 IEEE80211_FCTL_PM | IEEE80211_FCTL_MOREDATA); 321 if (!mgmt) 322 mask_fc &= ~cpu_to_le16(0x0070); 323 mask_fc |= cpu_to_le16(IEEE80211_FCTL_PROTECTED); 324 325 hdrlen = ieee80211_hdrlen(hdr->frame_control); 326 len_a = hdrlen - 2; 327 a4_included = ieee80211_has_a4(hdr->frame_control); 328 329 if (ieee80211_is_data_qos(hdr->frame_control)) 330 qos_tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK; 331 else 332 qos_tid = 0; 333 334 /* In CCM, the initial vectors (IV) used for CTR mode encryption and CBC 335 * mode authentication are not allowed to collide, yet both are derived 336 * from this vector b_0. We only set L := 1 here to indicate that the 337 * data size can be represented in (L+1) bytes. The CCM layer will take 338 * care of storing the data length in the top (L+1) bytes and setting 339 * and clearing the other bits as is required to derive the two IVs. 340 */ 341 b_0[0] = 0x1; 342 343 /* Nonce: Nonce Flags | A2 | PN 344 * Nonce Flags: Priority (b0..b3) | Management (b4) | Reserved (b5..b7) 345 */ 346 b_0[1] = qos_tid | (mgmt << 4); 347 memcpy(&b_0[2], hdr->addr2, ETH_ALEN); 348 memcpy(&b_0[8], pn, IEEE80211_CCMP_PN_LEN); 349 350 /* AAD (extra authenticate-only data) / masked 802.11 header 351 * FC | A1 | A2 | A3 | SC | [A4] | [QC] */ 352 put_unaligned_be16(len_a, &aad[0]); 353 put_unaligned(mask_fc, (__le16 *)&aad[2]); 354 memcpy(&aad[4], &hdr->addr1, 3 * ETH_ALEN); 355 356 /* Mask Seq#, leave Frag# */ 357 aad[22] = *((u8 *) &hdr->seq_ctrl) & 0x0f; 358 aad[23] = 0; 359 360 if (a4_included) { 361 memcpy(&aad[24], hdr->addr4, ETH_ALEN); 362 aad[30] = qos_tid; 363 aad[31] = 0; 364 } else { 365 memset(&aad[24], 0, ETH_ALEN + IEEE80211_QOS_CTL_LEN); 366 aad[24] = qos_tid; 367 } 368 } 369 370 371 static inline void ccmp_pn2hdr(u8 *hdr, u8 *pn, int key_id) 372 { 373 hdr[0] = pn[5]; 374 hdr[1] = pn[4]; 375 hdr[2] = 0; 376 hdr[3] = 0x20 | (key_id << 6); 377 hdr[4] = pn[3]; 378 hdr[5] = pn[2]; 379 hdr[6] = pn[1]; 380 hdr[7] = pn[0]; 381 } 382 383 384 static inline void ccmp_hdr2pn(u8 *pn, u8 *hdr) 385 { 386 pn[0] = hdr[7]; 387 pn[1] = hdr[6]; 388 pn[2] = hdr[5]; 389 pn[3] = hdr[4]; 390 pn[4] = hdr[1]; 391 pn[5] = hdr[0]; 392 } 393 394 395 static int ccmp_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb) 396 { 397 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; 398 struct ieee80211_key *key = tx->key; 399 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); 400 int hdrlen, len, tail; 401 u8 *pos; 402 u8 pn[6]; 403 u64 pn64; 404 u8 aad[2 * AES_BLOCK_SIZE]; 405 u8 b_0[AES_BLOCK_SIZE]; 406 407 if (info->control.hw_key && 408 !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV) && 409 !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE) && 410 !((info->control.hw_key->flags & 411 IEEE80211_KEY_FLAG_GENERATE_IV_MGMT) && 412 ieee80211_is_mgmt(hdr->frame_control))) { 413 /* 414 * hwaccel has no need for preallocated room for CCMP 415 * header or MIC fields 416 */ 417 return 0; 418 } 419 420 hdrlen = ieee80211_hdrlen(hdr->frame_control); 421 len = skb->len - hdrlen; 422 423 if (info->control.hw_key) 424 tail = 0; 425 else 426 tail = IEEE80211_CCMP_MIC_LEN; 427 428 if (WARN_ON(skb_tailroom(skb) < tail || 429 skb_headroom(skb) < IEEE80211_CCMP_HDR_LEN)) 430 return -1; 431 432 pos = skb_push(skb, IEEE80211_CCMP_HDR_LEN); 433 memmove(pos, pos + IEEE80211_CCMP_HDR_LEN, hdrlen); 434 skb_set_network_header(skb, skb_network_offset(skb) + 435 IEEE80211_CCMP_HDR_LEN); 436 437 /* the HW only needs room for the IV, but not the actual IV */ 438 if (info->control.hw_key && 439 (info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)) 440 return 0; 441 442 hdr = (struct ieee80211_hdr *) pos; 443 pos += hdrlen; 444 445 pn64 = atomic64_inc_return(&key->u.ccmp.tx_pn); 446 447 pn[5] = pn64; 448 pn[4] = pn64 >> 8; 449 pn[3] = pn64 >> 16; 450 pn[2] = pn64 >> 24; 451 pn[1] = pn64 >> 32; 452 pn[0] = pn64 >> 40; 453 454 ccmp_pn2hdr(pos, pn, key->conf.keyidx); 455 456 /* hwaccel - with software CCMP header */ 457 if (info->control.hw_key) 458 return 0; 459 460 pos += IEEE80211_CCMP_HDR_LEN; 461 ccmp_special_blocks(skb, pn, b_0, aad); 462 ieee80211_aes_ccm_encrypt(key->u.ccmp.tfm, b_0, aad, pos, len, 463 skb_put(skb, IEEE80211_CCMP_MIC_LEN)); 464 465 return 0; 466 } 467 468 469 ieee80211_tx_result 470 ieee80211_crypto_ccmp_encrypt(struct ieee80211_tx_data *tx) 471 { 472 struct sk_buff *skb; 473 474 ieee80211_tx_set_protected(tx); 475 476 skb_queue_walk(&tx->skbs, skb) { 477 if (ccmp_encrypt_skb(tx, skb) < 0) 478 return TX_DROP; 479 } 480 481 return TX_CONTINUE; 482 } 483 484 485 ieee80211_rx_result 486 ieee80211_crypto_ccmp_decrypt(struct ieee80211_rx_data *rx) 487 { 488 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data; 489 int hdrlen; 490 struct ieee80211_key *key = rx->key; 491 struct sk_buff *skb = rx->skb; 492 struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb); 493 u8 pn[IEEE80211_CCMP_PN_LEN]; 494 int data_len; 495 int queue; 496 497 hdrlen = ieee80211_hdrlen(hdr->frame_control); 498 499 if (!ieee80211_is_data(hdr->frame_control) && 500 !ieee80211_is_robust_mgmt_frame(skb)) 501 return RX_CONTINUE; 502 503 data_len = skb->len - hdrlen - IEEE80211_CCMP_HDR_LEN - 504 IEEE80211_CCMP_MIC_LEN; 505 if (!rx->sta || data_len < 0) 506 return RX_DROP_UNUSABLE; 507 508 if (status->flag & RX_FLAG_DECRYPTED) { 509 if (!pskb_may_pull(rx->skb, hdrlen + IEEE80211_CCMP_HDR_LEN)) 510 return RX_DROP_UNUSABLE; 511 } else { 512 if (skb_linearize(rx->skb)) 513 return RX_DROP_UNUSABLE; 514 } 515 516 ccmp_hdr2pn(pn, skb->data + hdrlen); 517 518 queue = rx->security_idx; 519 520 if (memcmp(pn, key->u.ccmp.rx_pn[queue], IEEE80211_CCMP_PN_LEN) <= 0) { 521 key->u.ccmp.replays++; 522 return RX_DROP_UNUSABLE; 523 } 524 525 if (!(status->flag & RX_FLAG_DECRYPTED)) { 526 u8 aad[2 * AES_BLOCK_SIZE]; 527 u8 b_0[AES_BLOCK_SIZE]; 528 /* hardware didn't decrypt/verify MIC */ 529 ccmp_special_blocks(skb, pn, b_0, aad); 530 531 if (ieee80211_aes_ccm_decrypt( 532 key->u.ccmp.tfm, b_0, aad, 533 skb->data + hdrlen + IEEE80211_CCMP_HDR_LEN, 534 data_len, 535 skb->data + skb->len - IEEE80211_CCMP_MIC_LEN)) 536 return RX_DROP_UNUSABLE; 537 } 538 539 memcpy(key->u.ccmp.rx_pn[queue], pn, IEEE80211_CCMP_PN_LEN); 540 541 /* Remove CCMP header and MIC */ 542 if (pskb_trim(skb, skb->len - IEEE80211_CCMP_MIC_LEN)) 543 return RX_DROP_UNUSABLE; 544 memmove(skb->data + IEEE80211_CCMP_HDR_LEN, skb->data, hdrlen); 545 skb_pull(skb, IEEE80211_CCMP_HDR_LEN); 546 547 return RX_CONTINUE; 548 } 549 550 static ieee80211_tx_result 551 ieee80211_crypto_cs_encrypt(struct ieee80211_tx_data *tx, 552 struct sk_buff *skb) 553 { 554 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data; 555 struct ieee80211_key *key = tx->key; 556 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); 557 const struct ieee80211_cipher_scheme *cs = key->sta->cipher_scheme; 558 int hdrlen; 559 u8 *pos; 560 561 if (info->control.hw_key && 562 !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)) { 563 /* hwaccel has no need for preallocated head room */ 564 return TX_CONTINUE; 565 } 566 567 if (unlikely(skb_headroom(skb) < cs->hdr_len && 568 pskb_expand_head(skb, cs->hdr_len, 0, GFP_ATOMIC))) 569 return TX_DROP; 570 571 hdrlen = ieee80211_hdrlen(hdr->frame_control); 572 573 pos = skb_push(skb, cs->hdr_len); 574 memmove(pos, pos + cs->hdr_len, hdrlen); 575 skb_set_network_header(skb, skb_network_offset(skb) + cs->hdr_len); 576 577 return TX_CONTINUE; 578 } 579 580 static inline int ieee80211_crypto_cs_pn_compare(u8 *pn1, u8 *pn2, int len) 581 { 582 int i; 583 584 /* pn is little endian */ 585 for (i = len - 1; i >= 0; i--) { 586 if (pn1[i] < pn2[i]) 587 return -1; 588 else if (pn1[i] > pn2[i]) 589 return 1; 590 } 591 592 return 0; 593 } 594 595 static ieee80211_rx_result 596 ieee80211_crypto_cs_decrypt(struct ieee80211_rx_data *rx) 597 { 598 struct ieee80211_key *key = rx->key; 599 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data; 600 const struct ieee80211_cipher_scheme *cs = NULL; 601 int hdrlen = ieee80211_hdrlen(hdr->frame_control); 602 struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb); 603 int data_len; 604 u8 *rx_pn; 605 u8 *skb_pn; 606 u8 qos_tid; 607 608 if (!rx->sta || !rx->sta->cipher_scheme || 609 !(status->flag & RX_FLAG_DECRYPTED)) 610 return RX_DROP_UNUSABLE; 611 612 if (!ieee80211_is_data(hdr->frame_control)) 613 return RX_CONTINUE; 614 615 cs = rx->sta->cipher_scheme; 616 617 data_len = rx->skb->len - hdrlen - cs->hdr_len; 618 619 if (data_len < 0) 620 return RX_DROP_UNUSABLE; 621 622 if (ieee80211_is_data_qos(hdr->frame_control)) 623 qos_tid = *ieee80211_get_qos_ctl(hdr) & 624 IEEE80211_QOS_CTL_TID_MASK; 625 else 626 qos_tid = 0; 627 628 if (skb_linearize(rx->skb)) 629 return RX_DROP_UNUSABLE; 630 631 hdr = (struct ieee80211_hdr *)rx->skb->data; 632 633 rx_pn = key->u.gen.rx_pn[qos_tid]; 634 skb_pn = rx->skb->data + hdrlen + cs->pn_off; 635 636 if (ieee80211_crypto_cs_pn_compare(skb_pn, rx_pn, cs->pn_len) <= 0) 637 return RX_DROP_UNUSABLE; 638 639 memcpy(rx_pn, skb_pn, cs->pn_len); 640 641 /* remove security header and MIC */ 642 if (pskb_trim(rx->skb, rx->skb->len - cs->mic_len)) 643 return RX_DROP_UNUSABLE; 644 645 memmove(rx->skb->data + cs->hdr_len, rx->skb->data, hdrlen); 646 skb_pull(rx->skb, cs->hdr_len); 647 648 return RX_CONTINUE; 649 } 650 651 static void bip_aad(struct sk_buff *skb, u8 *aad) 652 { 653 __le16 mask_fc; 654 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; 655 656 /* BIP AAD: FC(masked) || A1 || A2 || A3 */ 657 658 /* FC type/subtype */ 659 /* Mask FC Retry, PwrMgt, MoreData flags to zero */ 660 mask_fc = hdr->frame_control; 661 mask_fc &= ~cpu_to_le16(IEEE80211_FCTL_RETRY | IEEE80211_FCTL_PM | 662 IEEE80211_FCTL_MOREDATA); 663 put_unaligned(mask_fc, (__le16 *) &aad[0]); 664 /* A1 || A2 || A3 */ 665 memcpy(aad + 2, &hdr->addr1, 3 * ETH_ALEN); 666 } 667 668 669 static inline void bip_ipn_set64(u8 *d, u64 pn) 670 { 671 *d++ = pn; 672 *d++ = pn >> 8; 673 *d++ = pn >> 16; 674 *d++ = pn >> 24; 675 *d++ = pn >> 32; 676 *d = pn >> 40; 677 } 678 679 static inline void bip_ipn_swap(u8 *d, const u8 *s) 680 { 681 *d++ = s[5]; 682 *d++ = s[4]; 683 *d++ = s[3]; 684 *d++ = s[2]; 685 *d++ = s[1]; 686 *d = s[0]; 687 } 688 689 690 ieee80211_tx_result 691 ieee80211_crypto_aes_cmac_encrypt(struct ieee80211_tx_data *tx) 692 { 693 struct sk_buff *skb; 694 struct ieee80211_tx_info *info; 695 struct ieee80211_key *key = tx->key; 696 struct ieee80211_mmie *mmie; 697 u8 aad[20]; 698 u64 pn64; 699 700 if (WARN_ON(skb_queue_len(&tx->skbs) != 1)) 701 return TX_DROP; 702 703 skb = skb_peek(&tx->skbs); 704 705 info = IEEE80211_SKB_CB(skb); 706 707 if (info->control.hw_key) 708 return TX_CONTINUE; 709 710 if (WARN_ON(skb_tailroom(skb) < sizeof(*mmie))) 711 return TX_DROP; 712 713 mmie = (struct ieee80211_mmie *) skb_put(skb, sizeof(*mmie)); 714 mmie->element_id = WLAN_EID_MMIE; 715 mmie->length = sizeof(*mmie) - 2; 716 mmie->key_id = cpu_to_le16(key->conf.keyidx); 717 718 /* PN = PN + 1 */ 719 pn64 = atomic64_inc_return(&key->u.aes_cmac.tx_pn); 720 721 bip_ipn_set64(mmie->sequence_number, pn64); 722 723 bip_aad(skb, aad); 724 725 /* 726 * MIC = AES-128-CMAC(IGTK, AAD || Management Frame Body || MMIE, 64) 727 */ 728 ieee80211_aes_cmac(key->u.aes_cmac.tfm, aad, 729 skb->data + 24, skb->len - 24, mmie->mic); 730 731 return TX_CONTINUE; 732 } 733 734 735 ieee80211_rx_result 736 ieee80211_crypto_aes_cmac_decrypt(struct ieee80211_rx_data *rx) 737 { 738 struct sk_buff *skb = rx->skb; 739 struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb); 740 struct ieee80211_key *key = rx->key; 741 struct ieee80211_mmie *mmie; 742 u8 aad[20], mic[8], ipn[6]; 743 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; 744 745 if (!ieee80211_is_mgmt(hdr->frame_control)) 746 return RX_CONTINUE; 747 748 /* management frames are already linear */ 749 750 if (skb->len < 24 + sizeof(*mmie)) 751 return RX_DROP_UNUSABLE; 752 753 mmie = (struct ieee80211_mmie *) 754 (skb->data + skb->len - sizeof(*mmie)); 755 if (mmie->element_id != WLAN_EID_MMIE || 756 mmie->length != sizeof(*mmie) - 2) 757 return RX_DROP_UNUSABLE; /* Invalid MMIE */ 758 759 bip_ipn_swap(ipn, mmie->sequence_number); 760 761 if (memcmp(ipn, key->u.aes_cmac.rx_pn, 6) <= 0) { 762 key->u.aes_cmac.replays++; 763 return RX_DROP_UNUSABLE; 764 } 765 766 if (!(status->flag & RX_FLAG_DECRYPTED)) { 767 /* hardware didn't decrypt/verify MIC */ 768 bip_aad(skb, aad); 769 ieee80211_aes_cmac(key->u.aes_cmac.tfm, aad, 770 skb->data + 24, skb->len - 24, mic); 771 if (memcmp(mic, mmie->mic, sizeof(mmie->mic)) != 0) { 772 key->u.aes_cmac.icverrors++; 773 return RX_DROP_UNUSABLE; 774 } 775 } 776 777 memcpy(key->u.aes_cmac.rx_pn, ipn, 6); 778 779 /* Remove MMIE */ 780 skb_trim(skb, skb->len - sizeof(*mmie)); 781 782 return RX_CONTINUE; 783 } 784 785 ieee80211_tx_result 786 ieee80211_crypto_hw_encrypt(struct ieee80211_tx_data *tx) 787 { 788 struct sk_buff *skb; 789 struct ieee80211_tx_info *info = NULL; 790 ieee80211_tx_result res; 791 792 skb_queue_walk(&tx->skbs, skb) { 793 info = IEEE80211_SKB_CB(skb); 794 795 /* handle hw-only algorithm */ 796 if (!info->control.hw_key) 797 return TX_DROP; 798 799 if (tx->key->sta->cipher_scheme) { 800 res = ieee80211_crypto_cs_encrypt(tx, skb); 801 if (res != TX_CONTINUE) 802 return res; 803 } 804 } 805 806 ieee80211_tx_set_protected(tx); 807 808 return TX_CONTINUE; 809 } 810 811 ieee80211_rx_result 812 ieee80211_crypto_hw_decrypt(struct ieee80211_rx_data *rx) 813 { 814 if (rx->sta->cipher_scheme) 815 return ieee80211_crypto_cs_decrypt(rx); 816 817 return RX_DROP_UNUSABLE; 818 } 819