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 += TKIP_ICV_LEN; 66 67 if (WARN_ON(skb_tailroom(skb) < tail || 68 skb_headroom(skb) < 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; 108 109 if (!(status->flag & RX_FLAG_IV_STRIPPED) && rx->key) 110 goto update_iv; 111 112 return RX_CONTINUE; 113 } 114 115 /* 116 * Some hardware seems to generate Michael MIC failure reports; even 117 * though, the frame was not encrypted with TKIP and therefore has no 118 * MIC. Ignore the flag them to avoid triggering countermeasures. 119 */ 120 if (!rx->key || rx->key->conf.cipher != WLAN_CIPHER_SUITE_TKIP || 121 !(status->flag & RX_FLAG_DECRYPTED)) 122 return RX_CONTINUE; 123 124 if (rx->sdata->vif.type == NL80211_IFTYPE_AP && rx->key->conf.keyidx) { 125 /* 126 * APs with pairwise keys should never receive Michael MIC 127 * errors for non-zero keyidx because these are reserved for 128 * group keys and only the AP is sending real multicast 129 * frames in the BSS. ( 130 */ 131 return RX_DROP_UNUSABLE; 132 } 133 134 if (status->flag & RX_FLAG_MMIC_ERROR) 135 goto mic_fail; 136 137 hdrlen = ieee80211_hdrlen(hdr->frame_control); 138 if (skb->len < hdrlen + MICHAEL_MIC_LEN) 139 return RX_DROP_UNUSABLE; 140 141 if (skb_linearize(rx->skb)) 142 return RX_DROP_UNUSABLE; 143 hdr = (void *)skb->data; 144 145 data = skb->data + hdrlen; 146 data_len = skb->len - hdrlen - MICHAEL_MIC_LEN; 147 key = &rx->key->conf.key[NL80211_TKIP_DATA_OFFSET_RX_MIC_KEY]; 148 michael_mic(key, hdr, data, data_len, mic); 149 if (memcmp(mic, data + data_len, MICHAEL_MIC_LEN) != 0) 150 goto mic_fail; 151 152 /* remove Michael MIC from payload */ 153 skb_trim(skb, skb->len - MICHAEL_MIC_LEN); 154 155 update_iv: 156 /* update IV in key information to be able to detect replays */ 157 rx->key->u.tkip.rx[rx->security_idx].iv32 = rx->tkip_iv32; 158 rx->key->u.tkip.rx[rx->security_idx].iv16 = rx->tkip_iv16; 159 160 return RX_CONTINUE; 161 162 mic_fail: 163 /* 164 * In some cases the key can be unset - e.g. a multicast packet, in 165 * a driver that supports HW encryption. Send up the key idx only if 166 * the key is set. 167 */ 168 mac80211_ev_michael_mic_failure(rx->sdata, 169 rx->key ? rx->key->conf.keyidx : -1, 170 (void *) skb->data, NULL, GFP_ATOMIC); 171 return RX_DROP_UNUSABLE; 172 } 173 174 175 static int tkip_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb) 176 { 177 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; 178 struct ieee80211_key *key = tx->key; 179 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); 180 unsigned long flags; 181 unsigned int hdrlen; 182 int len, tail; 183 u8 *pos; 184 185 if (info->control.hw_key && 186 !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV) && 187 !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)) { 188 /* hwaccel - with no need for software-generated IV */ 189 return 0; 190 } 191 192 hdrlen = ieee80211_hdrlen(hdr->frame_control); 193 len = skb->len - hdrlen; 194 195 if (info->control.hw_key) 196 tail = 0; 197 else 198 tail = TKIP_ICV_LEN; 199 200 if (WARN_ON(skb_tailroom(skb) < tail || 201 skb_headroom(skb) < TKIP_IV_LEN)) 202 return -1; 203 204 pos = skb_push(skb, TKIP_IV_LEN); 205 memmove(pos, pos + TKIP_IV_LEN, hdrlen); 206 skb_set_network_header(skb, skb_network_offset(skb) + TKIP_IV_LEN); 207 pos += hdrlen; 208 209 /* the HW only needs room for the IV, but not the actual IV */ 210 if (info->control.hw_key && 211 (info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)) 212 return 0; 213 214 /* Increase IV for the frame */ 215 spin_lock_irqsave(&key->u.tkip.txlock, flags); 216 key->u.tkip.tx.iv16++; 217 if (key->u.tkip.tx.iv16 == 0) 218 key->u.tkip.tx.iv32++; 219 pos = ieee80211_tkip_add_iv(pos, key); 220 spin_unlock_irqrestore(&key->u.tkip.txlock, flags); 221 222 /* hwaccel - with software IV */ 223 if (info->control.hw_key) 224 return 0; 225 226 /* Add room for ICV */ 227 skb_put(skb, TKIP_ICV_LEN); 228 229 return ieee80211_tkip_encrypt_data(tx->local->wep_tx_tfm, 230 key, skb, pos, len); 231 } 232 233 234 ieee80211_tx_result 235 ieee80211_crypto_tkip_encrypt(struct ieee80211_tx_data *tx) 236 { 237 struct sk_buff *skb; 238 239 ieee80211_tx_set_protected(tx); 240 241 skb_queue_walk(&tx->skbs, skb) { 242 if (tkip_encrypt_skb(tx, skb) < 0) 243 return TX_DROP; 244 } 245 246 return TX_CONTINUE; 247 } 248 249 250 ieee80211_rx_result 251 ieee80211_crypto_tkip_decrypt(struct ieee80211_rx_data *rx) 252 { 253 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) rx->skb->data; 254 int hdrlen, res, hwaccel = 0; 255 struct ieee80211_key *key = rx->key; 256 struct sk_buff *skb = rx->skb; 257 struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb); 258 259 hdrlen = ieee80211_hdrlen(hdr->frame_control); 260 261 if (!ieee80211_is_data(hdr->frame_control)) 262 return RX_CONTINUE; 263 264 if (!rx->sta || skb->len - hdrlen < 12) 265 return RX_DROP_UNUSABLE; 266 267 /* it may be possible to optimize this a bit more */ 268 if (skb_linearize(rx->skb)) 269 return RX_DROP_UNUSABLE; 270 hdr = (void *)skb->data; 271 272 /* 273 * Let TKIP code verify IV, but skip decryption. 274 * In the case where hardware checks the IV as well, 275 * we don't even get here, see ieee80211_rx_h_decrypt() 276 */ 277 if (status->flag & RX_FLAG_DECRYPTED) 278 hwaccel = 1; 279 280 res = ieee80211_tkip_decrypt_data(rx->local->wep_rx_tfm, 281 key, skb->data + hdrlen, 282 skb->len - hdrlen, rx->sta->sta.addr, 283 hdr->addr1, hwaccel, rx->security_idx, 284 &rx->tkip_iv32, 285 &rx->tkip_iv16); 286 if (res != TKIP_DECRYPT_OK) 287 return RX_DROP_UNUSABLE; 288 289 /* Trim ICV */ 290 skb_trim(skb, skb->len - TKIP_ICV_LEN); 291 292 /* Remove IV */ 293 memmove(skb->data + TKIP_IV_LEN, skb->data, hdrlen); 294 skb_pull(skb, TKIP_IV_LEN); 295 296 return RX_CONTINUE; 297 } 298 299 300 static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *scratch, 301 int encrypted) 302 { 303 __le16 mask_fc; 304 int a4_included, mgmt; 305 u8 qos_tid; 306 u8 *b_0, *aad; 307 u16 data_len, len_a; 308 unsigned int hdrlen; 309 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data; 310 311 memset(scratch, 0, 6 * AES_BLOCK_SIZE); 312 313 b_0 = scratch + 3 * AES_BLOCK_SIZE; 314 aad = scratch + 4 * AES_BLOCK_SIZE; 315 316 /* 317 * Mask FC: zero subtype b4 b5 b6 (if not mgmt) 318 * Retry, PwrMgt, MoreData; set Protected 319 */ 320 mgmt = ieee80211_is_mgmt(hdr->frame_control); 321 mask_fc = hdr->frame_control; 322 mask_fc &= ~cpu_to_le16(IEEE80211_FCTL_RETRY | 323 IEEE80211_FCTL_PM | IEEE80211_FCTL_MOREDATA); 324 if (!mgmt) 325 mask_fc &= ~cpu_to_le16(0x0070); 326 mask_fc |= cpu_to_le16(IEEE80211_FCTL_PROTECTED); 327 328 hdrlen = ieee80211_hdrlen(hdr->frame_control); 329 len_a = hdrlen - 2; 330 a4_included = ieee80211_has_a4(hdr->frame_control); 331 332 if (ieee80211_is_data_qos(hdr->frame_control)) 333 qos_tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK; 334 else 335 qos_tid = 0; 336 337 data_len = skb->len - hdrlen - CCMP_HDR_LEN; 338 if (encrypted) 339 data_len -= CCMP_MIC_LEN; 340 341 /* First block, b_0 */ 342 b_0[0] = 0x59; /* flags: Adata: 1, M: 011, L: 001 */ 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, CCMP_PN_LEN); 349 /* l(m) */ 350 put_unaligned_be16(data_len, &b_0[14]); 351 352 /* AAD (extra authenticate-only data) / masked 802.11 header 353 * FC | A1 | A2 | A3 | SC | [A4] | [QC] */ 354 put_unaligned_be16(len_a, &aad[0]); 355 put_unaligned(mask_fc, (__le16 *)&aad[2]); 356 memcpy(&aad[4], &hdr->addr1, 3 * ETH_ALEN); 357 358 /* Mask Seq#, leave Frag# */ 359 aad[22] = *((u8 *) &hdr->seq_ctrl) & 0x0f; 360 aad[23] = 0; 361 362 if (a4_included) { 363 memcpy(&aad[24], hdr->addr4, ETH_ALEN); 364 aad[30] = qos_tid; 365 aad[31] = 0; 366 } else { 367 memset(&aad[24], 0, ETH_ALEN + IEEE80211_QOS_CTL_LEN); 368 aad[24] = qos_tid; 369 } 370 } 371 372 373 static inline void ccmp_pn2hdr(u8 *hdr, u8 *pn, int key_id) 374 { 375 hdr[0] = pn[5]; 376 hdr[1] = pn[4]; 377 hdr[2] = 0; 378 hdr[3] = 0x20 | (key_id << 6); 379 hdr[4] = pn[3]; 380 hdr[5] = pn[2]; 381 hdr[6] = pn[1]; 382 hdr[7] = pn[0]; 383 } 384 385 386 static inline void ccmp_hdr2pn(u8 *pn, u8 *hdr) 387 { 388 pn[0] = hdr[7]; 389 pn[1] = hdr[6]; 390 pn[2] = hdr[5]; 391 pn[3] = hdr[4]; 392 pn[4] = hdr[1]; 393 pn[5] = hdr[0]; 394 } 395 396 397 static int ccmp_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb) 398 { 399 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; 400 struct ieee80211_key *key = tx->key; 401 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); 402 int hdrlen, len, tail; 403 u8 *pos; 404 u8 pn[6]; 405 u64 pn64; 406 u8 scratch[6 * AES_BLOCK_SIZE]; 407 408 if (info->control.hw_key && 409 !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV) && 410 !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)) { 411 /* 412 * hwaccel has no need for preallocated room for CCMP 413 * header or MIC fields 414 */ 415 return 0; 416 } 417 418 hdrlen = ieee80211_hdrlen(hdr->frame_control); 419 len = skb->len - hdrlen; 420 421 if (info->control.hw_key) 422 tail = 0; 423 else 424 tail = CCMP_MIC_LEN; 425 426 if (WARN_ON(skb_tailroom(skb) < tail || 427 skb_headroom(skb) < CCMP_HDR_LEN)) 428 return -1; 429 430 pos = skb_push(skb, CCMP_HDR_LEN); 431 memmove(pos, pos + CCMP_HDR_LEN, hdrlen); 432 skb_set_network_header(skb, skb_network_offset(skb) + CCMP_HDR_LEN); 433 434 /* the HW only needs room for the IV, but not the actual IV */ 435 if (info->control.hw_key && 436 (info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)) 437 return 0; 438 439 hdr = (struct ieee80211_hdr *) pos; 440 pos += hdrlen; 441 442 pn64 = atomic64_inc_return(&key->u.ccmp.tx_pn); 443 444 pn[5] = pn64; 445 pn[4] = pn64 >> 8; 446 pn[3] = pn64 >> 16; 447 pn[2] = pn64 >> 24; 448 pn[1] = pn64 >> 32; 449 pn[0] = pn64 >> 40; 450 451 ccmp_pn2hdr(pos, pn, key->conf.keyidx); 452 453 /* hwaccel - with software CCMP header */ 454 if (info->control.hw_key) 455 return 0; 456 457 pos += CCMP_HDR_LEN; 458 ccmp_special_blocks(skb, pn, scratch, 0); 459 ieee80211_aes_ccm_encrypt(key->u.ccmp.tfm, scratch, pos, len, 460 pos, skb_put(skb, CCMP_MIC_LEN)); 461 462 return 0; 463 } 464 465 466 ieee80211_tx_result 467 ieee80211_crypto_ccmp_encrypt(struct ieee80211_tx_data *tx) 468 { 469 struct sk_buff *skb; 470 471 ieee80211_tx_set_protected(tx); 472 473 skb_queue_walk(&tx->skbs, skb) { 474 if (ccmp_encrypt_skb(tx, skb) < 0) 475 return TX_DROP; 476 } 477 478 return TX_CONTINUE; 479 } 480 481 482 ieee80211_rx_result 483 ieee80211_crypto_ccmp_decrypt(struct ieee80211_rx_data *rx) 484 { 485 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data; 486 int hdrlen; 487 struct ieee80211_key *key = rx->key; 488 struct sk_buff *skb = rx->skb; 489 struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb); 490 u8 pn[CCMP_PN_LEN]; 491 int data_len; 492 int queue; 493 494 hdrlen = ieee80211_hdrlen(hdr->frame_control); 495 496 if (!ieee80211_is_data(hdr->frame_control) && 497 !ieee80211_is_robust_mgmt_frame(hdr)) 498 return RX_CONTINUE; 499 500 data_len = skb->len - hdrlen - CCMP_HDR_LEN - CCMP_MIC_LEN; 501 if (!rx->sta || data_len < 0) 502 return RX_DROP_UNUSABLE; 503 504 if (status->flag & RX_FLAG_DECRYPTED) { 505 if (!pskb_may_pull(rx->skb, hdrlen + CCMP_HDR_LEN)) 506 return RX_DROP_UNUSABLE; 507 } else { 508 if (skb_linearize(rx->skb)) 509 return RX_DROP_UNUSABLE; 510 } 511 512 ccmp_hdr2pn(pn, skb->data + hdrlen); 513 514 queue = rx->security_idx; 515 516 if (memcmp(pn, key->u.ccmp.rx_pn[queue], CCMP_PN_LEN) <= 0) { 517 key->u.ccmp.replays++; 518 return RX_DROP_UNUSABLE; 519 } 520 521 if (!(status->flag & RX_FLAG_DECRYPTED)) { 522 u8 scratch[6 * AES_BLOCK_SIZE]; 523 /* hardware didn't decrypt/verify MIC */ 524 ccmp_special_blocks(skb, pn, scratch, 1); 525 526 if (ieee80211_aes_ccm_decrypt( 527 key->u.ccmp.tfm, scratch, 528 skb->data + hdrlen + CCMP_HDR_LEN, data_len, 529 skb->data + skb->len - CCMP_MIC_LEN, 530 skb->data + hdrlen + CCMP_HDR_LEN)) 531 return RX_DROP_UNUSABLE; 532 } 533 534 memcpy(key->u.ccmp.rx_pn[queue], pn, CCMP_PN_LEN); 535 536 /* Remove CCMP header and MIC */ 537 if (pskb_trim(skb, skb->len - CCMP_MIC_LEN)) 538 return RX_DROP_UNUSABLE; 539 memmove(skb->data + CCMP_HDR_LEN, skb->data, hdrlen); 540 skb_pull(skb, CCMP_HDR_LEN); 541 542 return RX_CONTINUE; 543 } 544 545 546 static void bip_aad(struct sk_buff *skb, u8 *aad) 547 { 548 /* BIP AAD: FC(masked) || A1 || A2 || A3 */ 549 550 /* FC type/subtype */ 551 aad[0] = skb->data[0]; 552 /* Mask FC Retry, PwrMgt, MoreData flags to zero */ 553 aad[1] = skb->data[1] & ~(BIT(4) | BIT(5) | BIT(6)); 554 /* A1 || A2 || A3 */ 555 memcpy(aad + 2, skb->data + 4, 3 * ETH_ALEN); 556 } 557 558 559 static inline void bip_ipn_set64(u8 *d, u64 pn) 560 { 561 *d++ = pn; 562 *d++ = pn >> 8; 563 *d++ = pn >> 16; 564 *d++ = pn >> 24; 565 *d++ = pn >> 32; 566 *d = pn >> 40; 567 } 568 569 static inline void bip_ipn_swap(u8 *d, const u8 *s) 570 { 571 *d++ = s[5]; 572 *d++ = s[4]; 573 *d++ = s[3]; 574 *d++ = s[2]; 575 *d++ = s[1]; 576 *d = s[0]; 577 } 578 579 580 ieee80211_tx_result 581 ieee80211_crypto_aes_cmac_encrypt(struct ieee80211_tx_data *tx) 582 { 583 struct sk_buff *skb; 584 struct ieee80211_tx_info *info; 585 struct ieee80211_key *key = tx->key; 586 struct ieee80211_mmie *mmie; 587 u8 aad[20]; 588 u64 pn64; 589 590 if (WARN_ON(skb_queue_len(&tx->skbs) != 1)) 591 return TX_DROP; 592 593 skb = skb_peek(&tx->skbs); 594 595 info = IEEE80211_SKB_CB(skb); 596 597 if (info->control.hw_key) 598 return TX_CONTINUE; 599 600 if (WARN_ON(skb_tailroom(skb) < sizeof(*mmie))) 601 return TX_DROP; 602 603 mmie = (struct ieee80211_mmie *) skb_put(skb, sizeof(*mmie)); 604 mmie->element_id = WLAN_EID_MMIE; 605 mmie->length = sizeof(*mmie) - 2; 606 mmie->key_id = cpu_to_le16(key->conf.keyidx); 607 608 /* PN = PN + 1 */ 609 pn64 = atomic64_inc_return(&key->u.aes_cmac.tx_pn); 610 611 bip_ipn_set64(mmie->sequence_number, pn64); 612 613 bip_aad(skb, aad); 614 615 /* 616 * MIC = AES-128-CMAC(IGTK, AAD || Management Frame Body || MMIE, 64) 617 */ 618 ieee80211_aes_cmac(key->u.aes_cmac.tfm, aad, 619 skb->data + 24, skb->len - 24, mmie->mic); 620 621 return TX_CONTINUE; 622 } 623 624 625 ieee80211_rx_result 626 ieee80211_crypto_aes_cmac_decrypt(struct ieee80211_rx_data *rx) 627 { 628 struct sk_buff *skb = rx->skb; 629 struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb); 630 struct ieee80211_key *key = rx->key; 631 struct ieee80211_mmie *mmie; 632 u8 aad[20], mic[8], ipn[6]; 633 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; 634 635 if (!ieee80211_is_mgmt(hdr->frame_control)) 636 return RX_CONTINUE; 637 638 /* management frames are already linear */ 639 640 if (skb->len < 24 + sizeof(*mmie)) 641 return RX_DROP_UNUSABLE; 642 643 mmie = (struct ieee80211_mmie *) 644 (skb->data + skb->len - sizeof(*mmie)); 645 if (mmie->element_id != WLAN_EID_MMIE || 646 mmie->length != sizeof(*mmie) - 2) 647 return RX_DROP_UNUSABLE; /* Invalid MMIE */ 648 649 bip_ipn_swap(ipn, mmie->sequence_number); 650 651 if (memcmp(ipn, key->u.aes_cmac.rx_pn, 6) <= 0) { 652 key->u.aes_cmac.replays++; 653 return RX_DROP_UNUSABLE; 654 } 655 656 if (!(status->flag & RX_FLAG_DECRYPTED)) { 657 /* hardware didn't decrypt/verify MIC */ 658 bip_aad(skb, aad); 659 ieee80211_aes_cmac(key->u.aes_cmac.tfm, aad, 660 skb->data + 24, skb->len - 24, mic); 661 if (memcmp(mic, mmie->mic, sizeof(mmie->mic)) != 0) { 662 key->u.aes_cmac.icverrors++; 663 return RX_DROP_UNUSABLE; 664 } 665 } 666 667 memcpy(key->u.aes_cmac.rx_pn, ipn, 6); 668 669 /* Remove MMIE */ 670 skb_trim(skb, skb->len - sizeof(*mmie)); 671 672 return RX_CONTINUE; 673 } 674 675 ieee80211_tx_result 676 ieee80211_crypto_hw_encrypt(struct ieee80211_tx_data *tx) 677 { 678 struct sk_buff *skb; 679 struct ieee80211_tx_info *info = NULL; 680 681 skb_queue_walk(&tx->skbs, skb) { 682 info = IEEE80211_SKB_CB(skb); 683 684 /* handle hw-only algorithm */ 685 if (!info->control.hw_key) 686 return TX_DROP; 687 } 688 689 ieee80211_tx_set_protected(tx); 690 691 return TX_CONTINUE; 692 } 693