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 /* 411 * hwaccel has no need for preallocated room for CCMP 412 * header or MIC fields 413 */ 414 return 0; 415 } 416 417 hdrlen = ieee80211_hdrlen(hdr->frame_control); 418 len = skb->len - hdrlen; 419 420 if (info->control.hw_key) 421 tail = 0; 422 else 423 tail = IEEE80211_CCMP_MIC_LEN; 424 425 if (WARN_ON(skb_tailroom(skb) < tail || 426 skb_headroom(skb) < IEEE80211_CCMP_HDR_LEN)) 427 return -1; 428 429 pos = skb_push(skb, IEEE80211_CCMP_HDR_LEN); 430 memmove(pos, pos + IEEE80211_CCMP_HDR_LEN, hdrlen); 431 skb_set_network_header(skb, skb_network_offset(skb) + 432 IEEE80211_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 += IEEE80211_CCMP_HDR_LEN; 458 ccmp_special_blocks(skb, pn, b_0, aad); 459 ieee80211_aes_ccm_encrypt(key->u.ccmp.tfm, b_0, aad, pos, len, 460 skb_put(skb, IEEE80211_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[IEEE80211_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(skb)) 498 return RX_CONTINUE; 499 500 data_len = skb->len - hdrlen - IEEE80211_CCMP_HDR_LEN - 501 IEEE80211_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 + IEEE80211_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], IEEE80211_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 aad[2 * AES_BLOCK_SIZE]; 524 u8 b_0[AES_BLOCK_SIZE]; 525 /* hardware didn't decrypt/verify MIC */ 526 ccmp_special_blocks(skb, pn, b_0, aad); 527 528 if (ieee80211_aes_ccm_decrypt( 529 key->u.ccmp.tfm, b_0, aad, 530 skb->data + hdrlen + IEEE80211_CCMP_HDR_LEN, 531 data_len, 532 skb->data + skb->len - IEEE80211_CCMP_MIC_LEN)) 533 return RX_DROP_UNUSABLE; 534 } 535 536 memcpy(key->u.ccmp.rx_pn[queue], pn, IEEE80211_CCMP_PN_LEN); 537 538 /* Remove CCMP header and MIC */ 539 if (pskb_trim(skb, skb->len - IEEE80211_CCMP_MIC_LEN)) 540 return RX_DROP_UNUSABLE; 541 memmove(skb->data + IEEE80211_CCMP_HDR_LEN, skb->data, hdrlen); 542 skb_pull(skb, IEEE80211_CCMP_HDR_LEN); 543 544 return RX_CONTINUE; 545 } 546 547 static ieee80211_tx_result 548 ieee80211_crypto_cs_encrypt(struct ieee80211_tx_data *tx, 549 struct sk_buff *skb) 550 { 551 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data; 552 struct ieee80211_key *key = tx->key; 553 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); 554 const struct ieee80211_cipher_scheme *cs = key->sta->cipher_scheme; 555 int hdrlen; 556 u8 *pos; 557 558 if (info->control.hw_key && 559 !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)) { 560 /* hwaccel has no need for preallocated head room */ 561 return TX_CONTINUE; 562 } 563 564 if (unlikely(skb_headroom(skb) < cs->hdr_len && 565 pskb_expand_head(skb, cs->hdr_len, 0, GFP_ATOMIC))) 566 return TX_DROP; 567 568 hdrlen = ieee80211_hdrlen(hdr->frame_control); 569 570 pos = skb_push(skb, cs->hdr_len); 571 memmove(pos, pos + cs->hdr_len, hdrlen); 572 skb_set_network_header(skb, skb_network_offset(skb) + cs->hdr_len); 573 574 return TX_CONTINUE; 575 } 576 577 static inline int ieee80211_crypto_cs_pn_compare(u8 *pn1, u8 *pn2, int len) 578 { 579 int i; 580 581 /* pn is little endian */ 582 for (i = len - 1; i >= 0; i--) { 583 if (pn1[i] < pn2[i]) 584 return -1; 585 else if (pn1[i] > pn2[i]) 586 return 1; 587 } 588 589 return 0; 590 } 591 592 static ieee80211_rx_result 593 ieee80211_crypto_cs_decrypt(struct ieee80211_rx_data *rx) 594 { 595 struct ieee80211_key *key = rx->key; 596 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data; 597 const struct ieee80211_cipher_scheme *cs = NULL; 598 int hdrlen = ieee80211_hdrlen(hdr->frame_control); 599 struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb); 600 int data_len; 601 u8 *rx_pn; 602 u8 *skb_pn; 603 u8 qos_tid; 604 605 if (!rx->sta || !rx->sta->cipher_scheme || 606 !(status->flag & RX_FLAG_DECRYPTED)) 607 return RX_DROP_UNUSABLE; 608 609 if (!ieee80211_is_data(hdr->frame_control)) 610 return RX_CONTINUE; 611 612 cs = rx->sta->cipher_scheme; 613 614 data_len = rx->skb->len - hdrlen - cs->hdr_len; 615 616 if (data_len < 0) 617 return RX_DROP_UNUSABLE; 618 619 if (ieee80211_is_data_qos(hdr->frame_control)) 620 qos_tid = *ieee80211_get_qos_ctl(hdr) & 621 IEEE80211_QOS_CTL_TID_MASK; 622 else 623 qos_tid = 0; 624 625 if (skb_linearize(rx->skb)) 626 return RX_DROP_UNUSABLE; 627 628 hdr = (struct ieee80211_hdr *)rx->skb->data; 629 630 rx_pn = key->u.gen.rx_pn[qos_tid]; 631 skb_pn = rx->skb->data + hdrlen + cs->pn_off; 632 633 if (ieee80211_crypto_cs_pn_compare(skb_pn, rx_pn, cs->pn_len) <= 0) 634 return RX_DROP_UNUSABLE; 635 636 memcpy(rx_pn, skb_pn, cs->pn_len); 637 638 /* remove security header and MIC */ 639 if (pskb_trim(rx->skb, rx->skb->len - cs->mic_len)) 640 return RX_DROP_UNUSABLE; 641 642 memmove(rx->skb->data + cs->hdr_len, rx->skb->data, hdrlen); 643 skb_pull(rx->skb, cs->hdr_len); 644 645 return RX_CONTINUE; 646 } 647 648 static void bip_aad(struct sk_buff *skb, u8 *aad) 649 { 650 __le16 mask_fc; 651 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; 652 653 /* BIP AAD: FC(masked) || A1 || A2 || A3 */ 654 655 /* FC type/subtype */ 656 /* Mask FC Retry, PwrMgt, MoreData flags to zero */ 657 mask_fc = hdr->frame_control; 658 mask_fc &= ~cpu_to_le16(IEEE80211_FCTL_RETRY | IEEE80211_FCTL_PM | 659 IEEE80211_FCTL_MOREDATA); 660 put_unaligned(mask_fc, (__le16 *) &aad[0]); 661 /* A1 || A2 || A3 */ 662 memcpy(aad + 2, &hdr->addr1, 3 * ETH_ALEN); 663 } 664 665 666 static inline void bip_ipn_set64(u8 *d, u64 pn) 667 { 668 *d++ = pn; 669 *d++ = pn >> 8; 670 *d++ = pn >> 16; 671 *d++ = pn >> 24; 672 *d++ = pn >> 32; 673 *d = pn >> 40; 674 } 675 676 static inline void bip_ipn_swap(u8 *d, const u8 *s) 677 { 678 *d++ = s[5]; 679 *d++ = s[4]; 680 *d++ = s[3]; 681 *d++ = s[2]; 682 *d++ = s[1]; 683 *d = s[0]; 684 } 685 686 687 ieee80211_tx_result 688 ieee80211_crypto_aes_cmac_encrypt(struct ieee80211_tx_data *tx) 689 { 690 struct sk_buff *skb; 691 struct ieee80211_tx_info *info; 692 struct ieee80211_key *key = tx->key; 693 struct ieee80211_mmie *mmie; 694 u8 aad[20]; 695 u64 pn64; 696 697 if (WARN_ON(skb_queue_len(&tx->skbs) != 1)) 698 return TX_DROP; 699 700 skb = skb_peek(&tx->skbs); 701 702 info = IEEE80211_SKB_CB(skb); 703 704 if (info->control.hw_key) 705 return TX_CONTINUE; 706 707 if (WARN_ON(skb_tailroom(skb) < sizeof(*mmie))) 708 return TX_DROP; 709 710 mmie = (struct ieee80211_mmie *) skb_put(skb, sizeof(*mmie)); 711 mmie->element_id = WLAN_EID_MMIE; 712 mmie->length = sizeof(*mmie) - 2; 713 mmie->key_id = cpu_to_le16(key->conf.keyidx); 714 715 /* PN = PN + 1 */ 716 pn64 = atomic64_inc_return(&key->u.aes_cmac.tx_pn); 717 718 bip_ipn_set64(mmie->sequence_number, pn64); 719 720 bip_aad(skb, aad); 721 722 /* 723 * MIC = AES-128-CMAC(IGTK, AAD || Management Frame Body || MMIE, 64) 724 */ 725 ieee80211_aes_cmac(key->u.aes_cmac.tfm, aad, 726 skb->data + 24, skb->len - 24, mmie->mic); 727 728 return TX_CONTINUE; 729 } 730 731 732 ieee80211_rx_result 733 ieee80211_crypto_aes_cmac_decrypt(struct ieee80211_rx_data *rx) 734 { 735 struct sk_buff *skb = rx->skb; 736 struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb); 737 struct ieee80211_key *key = rx->key; 738 struct ieee80211_mmie *mmie; 739 u8 aad[20], mic[8], ipn[6]; 740 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; 741 742 if (!ieee80211_is_mgmt(hdr->frame_control)) 743 return RX_CONTINUE; 744 745 /* management frames are already linear */ 746 747 if (skb->len < 24 + sizeof(*mmie)) 748 return RX_DROP_UNUSABLE; 749 750 mmie = (struct ieee80211_mmie *) 751 (skb->data + skb->len - sizeof(*mmie)); 752 if (mmie->element_id != WLAN_EID_MMIE || 753 mmie->length != sizeof(*mmie) - 2) 754 return RX_DROP_UNUSABLE; /* Invalid MMIE */ 755 756 bip_ipn_swap(ipn, mmie->sequence_number); 757 758 if (memcmp(ipn, key->u.aes_cmac.rx_pn, 6) <= 0) { 759 key->u.aes_cmac.replays++; 760 return RX_DROP_UNUSABLE; 761 } 762 763 if (!(status->flag & RX_FLAG_DECRYPTED)) { 764 /* hardware didn't decrypt/verify MIC */ 765 bip_aad(skb, aad); 766 ieee80211_aes_cmac(key->u.aes_cmac.tfm, aad, 767 skb->data + 24, skb->len - 24, mic); 768 if (memcmp(mic, mmie->mic, sizeof(mmie->mic)) != 0) { 769 key->u.aes_cmac.icverrors++; 770 return RX_DROP_UNUSABLE; 771 } 772 } 773 774 memcpy(key->u.aes_cmac.rx_pn, ipn, 6); 775 776 /* Remove MMIE */ 777 skb_trim(skb, skb->len - sizeof(*mmie)); 778 779 return RX_CONTINUE; 780 } 781 782 ieee80211_tx_result 783 ieee80211_crypto_hw_encrypt(struct ieee80211_tx_data *tx) 784 { 785 struct sk_buff *skb; 786 struct ieee80211_tx_info *info = NULL; 787 ieee80211_tx_result res; 788 789 skb_queue_walk(&tx->skbs, skb) { 790 info = IEEE80211_SKB_CB(skb); 791 792 /* handle hw-only algorithm */ 793 if (!info->control.hw_key) 794 return TX_DROP; 795 796 if (tx->key->sta->cipher_scheme) { 797 res = ieee80211_crypto_cs_encrypt(tx, skb); 798 if (res != TX_CONTINUE) 799 return res; 800 } 801 } 802 803 ieee80211_tx_set_protected(tx); 804 805 return TX_CONTINUE; 806 } 807 808 ieee80211_rx_result 809 ieee80211_crypto_hw_decrypt(struct ieee80211_rx_data *rx) 810 { 811 if (rx->sta->cipher_scheme) 812 return ieee80211_crypto_cs_decrypt(rx); 813 814 return RX_DROP_UNUSABLE; 815 } 816