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 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 /* 165 * In some cases the key can be unset - e.g. a multicast packet, in 166 * a driver that supports HW encryption. Send up the key idx only if 167 * the key is set. 168 */ 169 mac80211_ev_michael_mic_failure(rx->sdata, 170 rx->key ? rx->key->conf.keyidx : -1, 171 (void *) skb->data, NULL, GFP_ATOMIC); 172 return RX_DROP_UNUSABLE; 173 } 174 175 176 static int tkip_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb) 177 { 178 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; 179 struct ieee80211_key *key = tx->key; 180 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); 181 unsigned long flags; 182 unsigned int hdrlen; 183 int len, tail; 184 u8 *pos; 185 186 if (info->control.hw_key && 187 !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV) && 188 !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)) { 189 /* hwaccel - with no need for software-generated IV */ 190 return 0; 191 } 192 193 hdrlen = ieee80211_hdrlen(hdr->frame_control); 194 len = skb->len - hdrlen; 195 196 if (info->control.hw_key) 197 tail = 0; 198 else 199 tail = TKIP_ICV_LEN; 200 201 if (WARN_ON(skb_tailroom(skb) < tail || 202 skb_headroom(skb) < TKIP_IV_LEN)) 203 return -1; 204 205 pos = skb_push(skb, TKIP_IV_LEN); 206 memmove(pos, pos + TKIP_IV_LEN, hdrlen); 207 skb_set_network_header(skb, skb_network_offset(skb) + TKIP_IV_LEN); 208 pos += hdrlen; 209 210 /* the HW only needs room for the IV, but not the actual IV */ 211 if (info->control.hw_key && 212 (info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)) 213 return 0; 214 215 /* Increase IV for the frame */ 216 spin_lock_irqsave(&key->u.tkip.txlock, flags); 217 key->u.tkip.tx.iv16++; 218 if (key->u.tkip.tx.iv16 == 0) 219 key->u.tkip.tx.iv32++; 220 pos = ieee80211_tkip_add_iv(pos, key); 221 spin_unlock_irqrestore(&key->u.tkip.txlock, flags); 222 223 /* hwaccel - with software IV */ 224 if (info->control.hw_key) 225 return 0; 226 227 /* Add room for ICV */ 228 skb_put(skb, TKIP_ICV_LEN); 229 230 return ieee80211_tkip_encrypt_data(tx->local->wep_tx_tfm, 231 key, skb, pos, len); 232 } 233 234 235 ieee80211_tx_result 236 ieee80211_crypto_tkip_encrypt(struct ieee80211_tx_data *tx) 237 { 238 struct sk_buff *skb; 239 240 ieee80211_tx_set_protected(tx); 241 242 skb_queue_walk(&tx->skbs, skb) { 243 if (tkip_encrypt_skb(tx, skb) < 0) 244 return TX_DROP; 245 } 246 247 return TX_CONTINUE; 248 } 249 250 251 ieee80211_rx_result 252 ieee80211_crypto_tkip_decrypt(struct ieee80211_rx_data *rx) 253 { 254 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) rx->skb->data; 255 int hdrlen, res, hwaccel = 0; 256 struct ieee80211_key *key = rx->key; 257 struct sk_buff *skb = rx->skb; 258 struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb); 259 260 hdrlen = ieee80211_hdrlen(hdr->frame_control); 261 262 if (!ieee80211_is_data(hdr->frame_control)) 263 return RX_CONTINUE; 264 265 if (!rx->sta || skb->len - hdrlen < 12) 266 return RX_DROP_UNUSABLE; 267 268 /* it may be possible to optimize this a bit more */ 269 if (skb_linearize(rx->skb)) 270 return RX_DROP_UNUSABLE; 271 hdr = (void *)skb->data; 272 273 /* 274 * Let TKIP code verify IV, but skip decryption. 275 * In the case where hardware checks the IV as well, 276 * we don't even get here, see ieee80211_rx_h_decrypt() 277 */ 278 if (status->flag & RX_FLAG_DECRYPTED) 279 hwaccel = 1; 280 281 res = ieee80211_tkip_decrypt_data(rx->local->wep_rx_tfm, 282 key, skb->data + hdrlen, 283 skb->len - hdrlen, rx->sta->sta.addr, 284 hdr->addr1, hwaccel, rx->security_idx, 285 &rx->tkip_iv32, 286 &rx->tkip_iv16); 287 if (res != TKIP_DECRYPT_OK) 288 return RX_DROP_UNUSABLE; 289 290 /* Trim ICV */ 291 skb_trim(skb, skb->len - TKIP_ICV_LEN); 292 293 /* Remove IV */ 294 memmove(skb->data + TKIP_IV_LEN, skb->data, hdrlen); 295 skb_pull(skb, TKIP_IV_LEN); 296 297 return RX_CONTINUE; 298 } 299 300 301 static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *scratch, 302 int encrypted) 303 { 304 __le16 mask_fc; 305 int a4_included, mgmt; 306 u8 qos_tid; 307 u8 *b_0, *aad; 308 u16 data_len, len_a; 309 unsigned int hdrlen; 310 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data; 311 312 memset(scratch, 0, 6 * AES_BLOCK_SIZE); 313 314 b_0 = scratch + 3 * AES_BLOCK_SIZE; 315 aad = scratch + 4 * AES_BLOCK_SIZE; 316 317 /* 318 * Mask FC: zero subtype b4 b5 b6 (if not mgmt) 319 * Retry, PwrMgt, MoreData; set Protected 320 */ 321 mgmt = ieee80211_is_mgmt(hdr->frame_control); 322 mask_fc = hdr->frame_control; 323 mask_fc &= ~cpu_to_le16(IEEE80211_FCTL_RETRY | 324 IEEE80211_FCTL_PM | IEEE80211_FCTL_MOREDATA); 325 if (!mgmt) 326 mask_fc &= ~cpu_to_le16(0x0070); 327 mask_fc |= cpu_to_le16(IEEE80211_FCTL_PROTECTED); 328 329 hdrlen = ieee80211_hdrlen(hdr->frame_control); 330 len_a = hdrlen - 2; 331 a4_included = ieee80211_has_a4(hdr->frame_control); 332 333 if (ieee80211_is_data_qos(hdr->frame_control)) 334 qos_tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK; 335 else 336 qos_tid = 0; 337 338 data_len = skb->len - hdrlen - CCMP_HDR_LEN; 339 if (encrypted) 340 data_len -= CCMP_MIC_LEN; 341 342 /* First block, b_0 */ 343 b_0[0] = 0x59; /* flags: Adata: 1, M: 011, L: 001 */ 344 /* Nonce: Nonce Flags | A2 | PN 345 * Nonce Flags: Priority (b0..b3) | Management (b4) | Reserved (b5..b7) 346 */ 347 b_0[1] = qos_tid | (mgmt << 4); 348 memcpy(&b_0[2], hdr->addr2, ETH_ALEN); 349 memcpy(&b_0[8], pn, CCMP_PN_LEN); 350 /* l(m) */ 351 put_unaligned_be16(data_len, &b_0[14]); 352 353 /* AAD (extra authenticate-only data) / masked 802.11 header 354 * FC | A1 | A2 | A3 | SC | [A4] | [QC] */ 355 put_unaligned_be16(len_a, &aad[0]); 356 put_unaligned(mask_fc, (__le16 *)&aad[2]); 357 memcpy(&aad[4], &hdr->addr1, 3 * ETH_ALEN); 358 359 /* Mask Seq#, leave Frag# */ 360 aad[22] = *((u8 *) &hdr->seq_ctrl) & 0x0f; 361 aad[23] = 0; 362 363 if (a4_included) { 364 memcpy(&aad[24], hdr->addr4, ETH_ALEN); 365 aad[30] = qos_tid; 366 aad[31] = 0; 367 } else { 368 memset(&aad[24], 0, ETH_ALEN + IEEE80211_QOS_CTL_LEN); 369 aad[24] = qos_tid; 370 } 371 } 372 373 374 static inline void ccmp_pn2hdr(u8 *hdr, u8 *pn, int key_id) 375 { 376 hdr[0] = pn[5]; 377 hdr[1] = pn[4]; 378 hdr[2] = 0; 379 hdr[3] = 0x20 | (key_id << 6); 380 hdr[4] = pn[3]; 381 hdr[5] = pn[2]; 382 hdr[6] = pn[1]; 383 hdr[7] = pn[0]; 384 } 385 386 387 static inline void ccmp_hdr2pn(u8 *pn, u8 *hdr) 388 { 389 pn[0] = hdr[7]; 390 pn[1] = hdr[6]; 391 pn[2] = hdr[5]; 392 pn[3] = hdr[4]; 393 pn[4] = hdr[1]; 394 pn[5] = hdr[0]; 395 } 396 397 398 static int ccmp_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb) 399 { 400 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; 401 struct ieee80211_key *key = tx->key; 402 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); 403 int hdrlen, len, tail; 404 u8 *pos; 405 u8 pn[6]; 406 u64 pn64; 407 u8 scratch[6 * AES_BLOCK_SIZE]; 408 409 if (info->control.hw_key && 410 !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV) && 411 !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)) { 412 /* 413 * hwaccel has no need for preallocated room for CCMP 414 * header or MIC fields 415 */ 416 return 0; 417 } 418 419 hdrlen = ieee80211_hdrlen(hdr->frame_control); 420 len = skb->len - hdrlen; 421 422 if (info->control.hw_key) 423 tail = 0; 424 else 425 tail = CCMP_MIC_LEN; 426 427 if (WARN_ON(skb_tailroom(skb) < tail || 428 skb_headroom(skb) < CCMP_HDR_LEN)) 429 return -1; 430 431 pos = skb_push(skb, CCMP_HDR_LEN); 432 memmove(pos, pos + CCMP_HDR_LEN, hdrlen); 433 skb_set_network_header(skb, skb_network_offset(skb) + CCMP_HDR_LEN); 434 435 /* the HW only needs room for the IV, but not the actual IV */ 436 if (info->control.hw_key && 437 (info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)) 438 return 0; 439 440 hdr = (struct ieee80211_hdr *) pos; 441 pos += hdrlen; 442 443 pn64 = atomic64_inc_return(&key->u.ccmp.tx_pn); 444 445 pn[5] = pn64; 446 pn[4] = pn64 >> 8; 447 pn[3] = pn64 >> 16; 448 pn[2] = pn64 >> 24; 449 pn[1] = pn64 >> 32; 450 pn[0] = pn64 >> 40; 451 452 ccmp_pn2hdr(pos, pn, key->conf.keyidx); 453 454 /* hwaccel - with software CCMP header */ 455 if (info->control.hw_key) 456 return 0; 457 458 pos += CCMP_HDR_LEN; 459 ccmp_special_blocks(skb, pn, scratch, 0); 460 ieee80211_aes_ccm_encrypt(key->u.ccmp.tfm, scratch, pos, len, 461 pos, skb_put(skb, CCMP_MIC_LEN)); 462 463 return 0; 464 } 465 466 467 ieee80211_tx_result 468 ieee80211_crypto_ccmp_encrypt(struct ieee80211_tx_data *tx) 469 { 470 struct sk_buff *skb; 471 472 ieee80211_tx_set_protected(tx); 473 474 skb_queue_walk(&tx->skbs, skb) { 475 if (ccmp_encrypt_skb(tx, skb) < 0) 476 return TX_DROP; 477 } 478 479 return TX_CONTINUE; 480 } 481 482 483 ieee80211_rx_result 484 ieee80211_crypto_ccmp_decrypt(struct ieee80211_rx_data *rx) 485 { 486 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data; 487 int hdrlen; 488 struct ieee80211_key *key = rx->key; 489 struct sk_buff *skb = rx->skb; 490 struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb); 491 u8 pn[CCMP_PN_LEN]; 492 int data_len; 493 int queue; 494 495 hdrlen = ieee80211_hdrlen(hdr->frame_control); 496 497 if (!ieee80211_is_data(hdr->frame_control) && 498 !ieee80211_is_robust_mgmt_frame(hdr)) 499 return RX_CONTINUE; 500 501 data_len = skb->len - hdrlen - CCMP_HDR_LEN - CCMP_MIC_LEN; 502 if (!rx->sta || data_len < 0) 503 return RX_DROP_UNUSABLE; 504 505 if (status->flag & RX_FLAG_DECRYPTED) { 506 if (!pskb_may_pull(rx->skb, hdrlen + CCMP_HDR_LEN)) 507 return RX_DROP_UNUSABLE; 508 } else { 509 if (skb_linearize(rx->skb)) 510 return RX_DROP_UNUSABLE; 511 } 512 513 ccmp_hdr2pn(pn, skb->data + hdrlen); 514 515 queue = rx->security_idx; 516 517 if (memcmp(pn, key->u.ccmp.rx_pn[queue], CCMP_PN_LEN) <= 0) { 518 key->u.ccmp.replays++; 519 return RX_DROP_UNUSABLE; 520 } 521 522 if (!(status->flag & RX_FLAG_DECRYPTED)) { 523 u8 scratch[6 * AES_BLOCK_SIZE]; 524 /* hardware didn't decrypt/verify MIC */ 525 ccmp_special_blocks(skb, pn, scratch, 1); 526 527 if (ieee80211_aes_ccm_decrypt( 528 key->u.ccmp.tfm, scratch, 529 skb->data + hdrlen + CCMP_HDR_LEN, data_len, 530 skb->data + skb->len - CCMP_MIC_LEN, 531 skb->data + hdrlen + CCMP_HDR_LEN)) 532 return RX_DROP_UNUSABLE; 533 } 534 535 memcpy(key->u.ccmp.rx_pn[queue], pn, CCMP_PN_LEN); 536 537 /* Remove CCMP header and MIC */ 538 if (pskb_trim(skb, skb->len - CCMP_MIC_LEN)) 539 return RX_DROP_UNUSABLE; 540 memmove(skb->data + CCMP_HDR_LEN, skb->data, hdrlen); 541 skb_pull(skb, CCMP_HDR_LEN); 542 543 return RX_CONTINUE; 544 } 545 546 547 static void bip_aad(struct sk_buff *skb, u8 *aad) 548 { 549 __le16 mask_fc; 550 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; 551 552 /* BIP AAD: FC(masked) || A1 || A2 || A3 */ 553 554 /* FC type/subtype */ 555 /* Mask FC Retry, PwrMgt, MoreData flags to zero */ 556 mask_fc = hdr->frame_control; 557 mask_fc &= ~cpu_to_le16(IEEE80211_FCTL_RETRY | IEEE80211_FCTL_PM | 558 IEEE80211_FCTL_MOREDATA); 559 put_unaligned(mask_fc, (__le16 *) &aad[0]); 560 /* A1 || A2 || A3 */ 561 memcpy(aad + 2, &hdr->addr1, 3 * ETH_ALEN); 562 } 563 564 565 static inline void bip_ipn_set64(u8 *d, u64 pn) 566 { 567 *d++ = pn; 568 *d++ = pn >> 8; 569 *d++ = pn >> 16; 570 *d++ = pn >> 24; 571 *d++ = pn >> 32; 572 *d = pn >> 40; 573 } 574 575 static inline void bip_ipn_swap(u8 *d, const u8 *s) 576 { 577 *d++ = s[5]; 578 *d++ = s[4]; 579 *d++ = s[3]; 580 *d++ = s[2]; 581 *d++ = s[1]; 582 *d = s[0]; 583 } 584 585 586 ieee80211_tx_result 587 ieee80211_crypto_aes_cmac_encrypt(struct ieee80211_tx_data *tx) 588 { 589 struct sk_buff *skb; 590 struct ieee80211_tx_info *info; 591 struct ieee80211_key *key = tx->key; 592 struct ieee80211_mmie *mmie; 593 u8 aad[20]; 594 u64 pn64; 595 596 if (WARN_ON(skb_queue_len(&tx->skbs) != 1)) 597 return TX_DROP; 598 599 skb = skb_peek(&tx->skbs); 600 601 info = IEEE80211_SKB_CB(skb); 602 603 if (info->control.hw_key) 604 return TX_CONTINUE; 605 606 if (WARN_ON(skb_tailroom(skb) < sizeof(*mmie))) 607 return TX_DROP; 608 609 mmie = (struct ieee80211_mmie *) skb_put(skb, sizeof(*mmie)); 610 mmie->element_id = WLAN_EID_MMIE; 611 mmie->length = sizeof(*mmie) - 2; 612 mmie->key_id = cpu_to_le16(key->conf.keyidx); 613 614 /* PN = PN + 1 */ 615 pn64 = atomic64_inc_return(&key->u.aes_cmac.tx_pn); 616 617 bip_ipn_set64(mmie->sequence_number, pn64); 618 619 bip_aad(skb, aad); 620 621 /* 622 * MIC = AES-128-CMAC(IGTK, AAD || Management Frame Body || MMIE, 64) 623 */ 624 ieee80211_aes_cmac(key->u.aes_cmac.tfm, aad, 625 skb->data + 24, skb->len - 24, mmie->mic); 626 627 return TX_CONTINUE; 628 } 629 630 631 ieee80211_rx_result 632 ieee80211_crypto_aes_cmac_decrypt(struct ieee80211_rx_data *rx) 633 { 634 struct sk_buff *skb = rx->skb; 635 struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb); 636 struct ieee80211_key *key = rx->key; 637 struct ieee80211_mmie *mmie; 638 u8 aad[20], mic[8], ipn[6]; 639 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; 640 641 if (!ieee80211_is_mgmt(hdr->frame_control)) 642 return RX_CONTINUE; 643 644 /* management frames are already linear */ 645 646 if (skb->len < 24 + sizeof(*mmie)) 647 return RX_DROP_UNUSABLE; 648 649 mmie = (struct ieee80211_mmie *) 650 (skb->data + skb->len - sizeof(*mmie)); 651 if (mmie->element_id != WLAN_EID_MMIE || 652 mmie->length != sizeof(*mmie) - 2) 653 return RX_DROP_UNUSABLE; /* Invalid MMIE */ 654 655 bip_ipn_swap(ipn, mmie->sequence_number); 656 657 if (memcmp(ipn, key->u.aes_cmac.rx_pn, 6) <= 0) { 658 key->u.aes_cmac.replays++; 659 return RX_DROP_UNUSABLE; 660 } 661 662 if (!(status->flag & RX_FLAG_DECRYPTED)) { 663 /* hardware didn't decrypt/verify MIC */ 664 bip_aad(skb, aad); 665 ieee80211_aes_cmac(key->u.aes_cmac.tfm, aad, 666 skb->data + 24, skb->len - 24, mic); 667 if (memcmp(mic, mmie->mic, sizeof(mmie->mic)) != 0) { 668 key->u.aes_cmac.icverrors++; 669 return RX_DROP_UNUSABLE; 670 } 671 } 672 673 memcpy(key->u.aes_cmac.rx_pn, ipn, 6); 674 675 /* Remove MMIE */ 676 skb_trim(skb, skb->len - sizeof(*mmie)); 677 678 return RX_CONTINUE; 679 } 680 681 ieee80211_tx_result 682 ieee80211_crypto_hw_encrypt(struct ieee80211_tx_data *tx) 683 { 684 struct sk_buff *skb; 685 struct ieee80211_tx_info *info = NULL; 686 687 skb_queue_walk(&tx->skbs, skb) { 688 info = IEEE80211_SKB_CB(skb); 689 690 /* handle hw-only algorithm */ 691 if (!info->control.hw_key) 692 return TX_DROP; 693 } 694 695 ieee80211_tx_set_protected(tx); 696 697 return TX_CONTINUE; 698 } 699