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(skb_tailroom(skb) < tail || 68 skb_headroom(skb) < IEEE80211_TKIP_IV_LEN, 69 "mmic: not enough head/tail (%d/%d,%d/%d)\n", 70 skb_headroom(skb), IEEE80211_TKIP_IV_LEN, 71 skb_tailroom(skb), tail)) 72 return TX_DROP; 73 74 key = &tx->key->conf.key[NL80211_TKIP_DATA_OFFSET_TX_MIC_KEY]; 75 mic = skb_put(skb, MICHAEL_MIC_LEN); 76 michael_mic(key, hdr, data, data_len, mic); 77 if (unlikely(info->flags & IEEE80211_TX_INTFL_TKIP_MIC_FAILURE)) 78 mic[0]++; 79 80 return TX_CONTINUE; 81 } 82 83 84 ieee80211_rx_result 85 ieee80211_rx_h_michael_mic_verify(struct ieee80211_rx_data *rx) 86 { 87 u8 *data, *key = NULL; 88 size_t data_len; 89 unsigned int hdrlen; 90 u8 mic[MICHAEL_MIC_LEN]; 91 struct sk_buff *skb = rx->skb; 92 struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb); 93 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data; 94 95 /* 96 * it makes no sense to check for MIC errors on anything other 97 * than data frames. 98 */ 99 if (!ieee80211_is_data_present(hdr->frame_control)) 100 return RX_CONTINUE; 101 102 /* 103 * No way to verify the MIC if the hardware stripped it or 104 * the IV with the key index. In this case we have solely rely 105 * on the driver to set RX_FLAG_MMIC_ERROR in the event of a 106 * MIC failure report. 107 */ 108 if (status->flag & (RX_FLAG_MMIC_STRIPPED | RX_FLAG_IV_STRIPPED)) { 109 if (status->flag & RX_FLAG_MMIC_ERROR) 110 goto mic_fail_no_key; 111 112 if (!(status->flag & RX_FLAG_IV_STRIPPED) && rx->key && 113 rx->key->conf.cipher == WLAN_CIPHER_SUITE_TKIP) 114 goto update_iv; 115 116 return RX_CONTINUE; 117 } 118 119 /* 120 * Some hardware seems to generate Michael MIC failure reports; even 121 * though, the frame was not encrypted with TKIP and therefore has no 122 * MIC. Ignore the flag them to avoid triggering countermeasures. 123 */ 124 if (!rx->key || rx->key->conf.cipher != WLAN_CIPHER_SUITE_TKIP || 125 !(status->flag & RX_FLAG_DECRYPTED)) 126 return RX_CONTINUE; 127 128 if (rx->sdata->vif.type == NL80211_IFTYPE_AP && rx->key->conf.keyidx) { 129 /* 130 * APs with pairwise keys should never receive Michael MIC 131 * errors for non-zero keyidx because these are reserved for 132 * group keys and only the AP is sending real multicast 133 * frames in the BSS. 134 */ 135 return RX_DROP_UNUSABLE; 136 } 137 138 if (status->flag & RX_FLAG_MMIC_ERROR) 139 goto mic_fail; 140 141 hdrlen = ieee80211_hdrlen(hdr->frame_control); 142 if (skb->len < hdrlen + MICHAEL_MIC_LEN) 143 return RX_DROP_UNUSABLE; 144 145 if (skb_linearize(rx->skb)) 146 return RX_DROP_UNUSABLE; 147 hdr = (void *)skb->data; 148 149 data = skb->data + hdrlen; 150 data_len = skb->len - hdrlen - MICHAEL_MIC_LEN; 151 key = &rx->key->conf.key[NL80211_TKIP_DATA_OFFSET_RX_MIC_KEY]; 152 michael_mic(key, hdr, data, data_len, mic); 153 if (memcmp(mic, data + data_len, MICHAEL_MIC_LEN) != 0) 154 goto mic_fail; 155 156 /* remove Michael MIC from payload */ 157 skb_trim(skb, skb->len - MICHAEL_MIC_LEN); 158 159 update_iv: 160 /* update IV in key information to be able to detect replays */ 161 rx->key->u.tkip.rx[rx->security_idx].iv32 = rx->tkip_iv32; 162 rx->key->u.tkip.rx[rx->security_idx].iv16 = rx->tkip_iv16; 163 164 return RX_CONTINUE; 165 166 mic_fail: 167 rx->key->u.tkip.mic_failures++; 168 169 mic_fail_no_key: 170 /* 171 * In some cases the key can be unset - e.g. a multicast packet, in 172 * a driver that supports HW encryption. Send up the key idx only if 173 * the key is set. 174 */ 175 mac80211_ev_michael_mic_failure(rx->sdata, 176 rx->key ? rx->key->conf.keyidx : -1, 177 (void *) skb->data, NULL, GFP_ATOMIC); 178 return RX_DROP_UNUSABLE; 179 } 180 181 182 static int tkip_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb) 183 { 184 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; 185 struct ieee80211_key *key = tx->key; 186 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); 187 unsigned int hdrlen; 188 int len, tail; 189 u8 *pos; 190 191 if (info->control.hw_key && 192 !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV) && 193 !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)) { 194 /* hwaccel - with no need for software-generated IV */ 195 return 0; 196 } 197 198 hdrlen = ieee80211_hdrlen(hdr->frame_control); 199 len = skb->len - hdrlen; 200 201 if (info->control.hw_key) 202 tail = 0; 203 else 204 tail = IEEE80211_TKIP_ICV_LEN; 205 206 if (WARN_ON(skb_tailroom(skb) < tail || 207 skb_headroom(skb) < IEEE80211_TKIP_IV_LEN)) 208 return -1; 209 210 pos = skb_push(skb, IEEE80211_TKIP_IV_LEN); 211 memmove(pos, pos + IEEE80211_TKIP_IV_LEN, hdrlen); 212 skb_set_network_header(skb, skb_network_offset(skb) + 213 IEEE80211_TKIP_IV_LEN); 214 pos += hdrlen; 215 216 /* the HW only needs room for the IV, but not the actual IV */ 217 if (info->control.hw_key && 218 (info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)) 219 return 0; 220 221 /* Increase IV for the frame */ 222 spin_lock(&key->u.tkip.txlock); 223 key->u.tkip.tx.iv16++; 224 if (key->u.tkip.tx.iv16 == 0) 225 key->u.tkip.tx.iv32++; 226 pos = ieee80211_tkip_add_iv(pos, key); 227 spin_unlock(&key->u.tkip.txlock); 228 229 /* hwaccel - with software IV */ 230 if (info->control.hw_key) 231 return 0; 232 233 /* Add room for ICV */ 234 skb_put(skb, IEEE80211_TKIP_ICV_LEN); 235 236 return ieee80211_tkip_encrypt_data(tx->local->wep_tx_tfm, 237 key, skb, pos, len); 238 } 239 240 241 ieee80211_tx_result 242 ieee80211_crypto_tkip_encrypt(struct ieee80211_tx_data *tx) 243 { 244 struct sk_buff *skb; 245 246 ieee80211_tx_set_protected(tx); 247 248 skb_queue_walk(&tx->skbs, skb) { 249 if (tkip_encrypt_skb(tx, skb) < 0) 250 return TX_DROP; 251 } 252 253 return TX_CONTINUE; 254 } 255 256 257 ieee80211_rx_result 258 ieee80211_crypto_tkip_decrypt(struct ieee80211_rx_data *rx) 259 { 260 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) rx->skb->data; 261 int hdrlen, res, hwaccel = 0; 262 struct ieee80211_key *key = rx->key; 263 struct sk_buff *skb = rx->skb; 264 struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb); 265 266 hdrlen = ieee80211_hdrlen(hdr->frame_control); 267 268 if (!ieee80211_is_data(hdr->frame_control)) 269 return RX_CONTINUE; 270 271 if (!rx->sta || skb->len - hdrlen < 12) 272 return RX_DROP_UNUSABLE; 273 274 /* it may be possible to optimize this a bit more */ 275 if (skb_linearize(rx->skb)) 276 return RX_DROP_UNUSABLE; 277 hdr = (void *)skb->data; 278 279 /* 280 * Let TKIP code verify IV, but skip decryption. 281 * In the case where hardware checks the IV as well, 282 * we don't even get here, see ieee80211_rx_h_decrypt() 283 */ 284 if (status->flag & RX_FLAG_DECRYPTED) 285 hwaccel = 1; 286 287 res = ieee80211_tkip_decrypt_data(rx->local->wep_rx_tfm, 288 key, skb->data + hdrlen, 289 skb->len - hdrlen, rx->sta->sta.addr, 290 hdr->addr1, hwaccel, rx->security_idx, 291 &rx->tkip_iv32, 292 &rx->tkip_iv16); 293 if (res != TKIP_DECRYPT_OK) 294 return RX_DROP_UNUSABLE; 295 296 /* Trim ICV */ 297 skb_trim(skb, skb->len - IEEE80211_TKIP_ICV_LEN); 298 299 /* Remove IV */ 300 memmove(skb->data + IEEE80211_TKIP_IV_LEN, skb->data, hdrlen); 301 skb_pull(skb, IEEE80211_TKIP_IV_LEN); 302 303 return RX_CONTINUE; 304 } 305 306 307 static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *b_0, u8 *aad) 308 { 309 __le16 mask_fc; 310 int a4_included, mgmt; 311 u8 qos_tid; 312 u16 len_a; 313 unsigned int hdrlen; 314 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data; 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 /* In CCM, the initial vectors (IV) used for CTR mode encryption and CBC 338 * mode authentication are not allowed to collide, yet both are derived 339 * from this vector b_0. We only set L := 1 here to indicate that the 340 * data size can be represented in (L+1) bytes. The CCM layer will take 341 * care of storing the data length in the top (L+1) bytes and setting 342 * and clearing the other bits as is required to derive the two IVs. 343 */ 344 b_0[0] = 0x1; 345 346 /* Nonce: Nonce Flags | A2 | PN 347 * Nonce Flags: Priority (b0..b3) | Management (b4) | Reserved (b5..b7) 348 */ 349 b_0[1] = qos_tid | (mgmt << 4); 350 memcpy(&b_0[2], hdr->addr2, ETH_ALEN); 351 memcpy(&b_0[8], pn, IEEE80211_CCMP_PN_LEN); 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 aad[2 * AES_BLOCK_SIZE]; 408 u8 b_0[AES_BLOCK_SIZE]; 409 410 if (info->control.hw_key && 411 !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV) && 412 !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE) && 413 !((info->control.hw_key->flags & 414 IEEE80211_KEY_FLAG_GENERATE_IV_MGMT) && 415 ieee80211_is_mgmt(hdr->frame_control))) { 416 /* 417 * hwaccel has no need for preallocated room for CCMP 418 * header or MIC fields 419 */ 420 return 0; 421 } 422 423 hdrlen = ieee80211_hdrlen(hdr->frame_control); 424 len = skb->len - hdrlen; 425 426 if (info->control.hw_key) 427 tail = 0; 428 else 429 tail = IEEE80211_CCMP_MIC_LEN; 430 431 if (WARN_ON(skb_tailroom(skb) < tail || 432 skb_headroom(skb) < IEEE80211_CCMP_HDR_LEN)) 433 return -1; 434 435 pos = skb_push(skb, IEEE80211_CCMP_HDR_LEN); 436 memmove(pos, pos + IEEE80211_CCMP_HDR_LEN, hdrlen); 437 skb_set_network_header(skb, skb_network_offset(skb) + 438 IEEE80211_CCMP_HDR_LEN); 439 440 /* the HW only needs room for the IV, but not the actual IV */ 441 if (info->control.hw_key && 442 (info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)) 443 return 0; 444 445 hdr = (struct ieee80211_hdr *) pos; 446 pos += hdrlen; 447 448 pn64 = atomic64_inc_return(&key->u.ccmp.tx_pn); 449 450 pn[5] = pn64; 451 pn[4] = pn64 >> 8; 452 pn[3] = pn64 >> 16; 453 pn[2] = pn64 >> 24; 454 pn[1] = pn64 >> 32; 455 pn[0] = pn64 >> 40; 456 457 ccmp_pn2hdr(pos, pn, key->conf.keyidx); 458 459 /* hwaccel - with software CCMP header */ 460 if (info->control.hw_key) 461 return 0; 462 463 pos += IEEE80211_CCMP_HDR_LEN; 464 ccmp_special_blocks(skb, pn, b_0, aad); 465 ieee80211_aes_ccm_encrypt(key->u.ccmp.tfm, b_0, aad, pos, len, 466 skb_put(skb, IEEE80211_CCMP_MIC_LEN)); 467 468 return 0; 469 } 470 471 472 ieee80211_tx_result 473 ieee80211_crypto_ccmp_encrypt(struct ieee80211_tx_data *tx) 474 { 475 struct sk_buff *skb; 476 477 ieee80211_tx_set_protected(tx); 478 479 skb_queue_walk(&tx->skbs, skb) { 480 if (ccmp_encrypt_skb(tx, skb) < 0) 481 return TX_DROP; 482 } 483 484 return TX_CONTINUE; 485 } 486 487 488 ieee80211_rx_result 489 ieee80211_crypto_ccmp_decrypt(struct ieee80211_rx_data *rx) 490 { 491 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data; 492 int hdrlen; 493 struct ieee80211_key *key = rx->key; 494 struct sk_buff *skb = rx->skb; 495 struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb); 496 u8 pn[IEEE80211_CCMP_PN_LEN]; 497 int data_len; 498 int queue; 499 500 hdrlen = ieee80211_hdrlen(hdr->frame_control); 501 502 if (!ieee80211_is_data(hdr->frame_control) && 503 !ieee80211_is_robust_mgmt_frame(skb)) 504 return RX_CONTINUE; 505 506 data_len = skb->len - hdrlen - IEEE80211_CCMP_HDR_LEN - 507 IEEE80211_CCMP_MIC_LEN; 508 if (!rx->sta || data_len < 0) 509 return RX_DROP_UNUSABLE; 510 511 if (status->flag & RX_FLAG_DECRYPTED) { 512 if (!pskb_may_pull(rx->skb, hdrlen + IEEE80211_CCMP_HDR_LEN)) 513 return RX_DROP_UNUSABLE; 514 } else { 515 if (skb_linearize(rx->skb)) 516 return RX_DROP_UNUSABLE; 517 } 518 519 ccmp_hdr2pn(pn, skb->data + hdrlen); 520 521 queue = rx->security_idx; 522 523 if (memcmp(pn, key->u.ccmp.rx_pn[queue], IEEE80211_CCMP_PN_LEN) <= 0) { 524 key->u.ccmp.replays++; 525 return RX_DROP_UNUSABLE; 526 } 527 528 if (!(status->flag & RX_FLAG_DECRYPTED)) { 529 u8 aad[2 * AES_BLOCK_SIZE]; 530 u8 b_0[AES_BLOCK_SIZE]; 531 /* hardware didn't decrypt/verify MIC */ 532 ccmp_special_blocks(skb, pn, b_0, aad); 533 534 if (ieee80211_aes_ccm_decrypt( 535 key->u.ccmp.tfm, b_0, aad, 536 skb->data + hdrlen + IEEE80211_CCMP_HDR_LEN, 537 data_len, 538 skb->data + skb->len - IEEE80211_CCMP_MIC_LEN)) 539 return RX_DROP_UNUSABLE; 540 } 541 542 memcpy(key->u.ccmp.rx_pn[queue], pn, IEEE80211_CCMP_PN_LEN); 543 544 /* Remove CCMP header and MIC */ 545 if (pskb_trim(skb, skb->len - IEEE80211_CCMP_MIC_LEN)) 546 return RX_DROP_UNUSABLE; 547 memmove(skb->data + IEEE80211_CCMP_HDR_LEN, skb->data, hdrlen); 548 skb_pull(skb, IEEE80211_CCMP_HDR_LEN); 549 550 return RX_CONTINUE; 551 } 552 553 static ieee80211_tx_result 554 ieee80211_crypto_cs_encrypt(struct ieee80211_tx_data *tx, 555 struct sk_buff *skb) 556 { 557 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data; 558 struct ieee80211_key *key = tx->key; 559 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); 560 const struct ieee80211_cipher_scheme *cs = key->sta->cipher_scheme; 561 int hdrlen; 562 u8 *pos; 563 564 if (info->control.hw_key && 565 !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)) { 566 /* hwaccel has no need for preallocated head room */ 567 return TX_CONTINUE; 568 } 569 570 if (unlikely(skb_headroom(skb) < cs->hdr_len && 571 pskb_expand_head(skb, cs->hdr_len, 0, GFP_ATOMIC))) 572 return TX_DROP; 573 574 hdrlen = ieee80211_hdrlen(hdr->frame_control); 575 576 pos = skb_push(skb, cs->hdr_len); 577 memmove(pos, pos + cs->hdr_len, hdrlen); 578 skb_set_network_header(skb, skb_network_offset(skb) + cs->hdr_len); 579 580 return TX_CONTINUE; 581 } 582 583 static inline int ieee80211_crypto_cs_pn_compare(u8 *pn1, u8 *pn2, int len) 584 { 585 int i; 586 587 /* pn is little endian */ 588 for (i = len - 1; i >= 0; i--) { 589 if (pn1[i] < pn2[i]) 590 return -1; 591 else if (pn1[i] > pn2[i]) 592 return 1; 593 } 594 595 return 0; 596 } 597 598 static ieee80211_rx_result 599 ieee80211_crypto_cs_decrypt(struct ieee80211_rx_data *rx) 600 { 601 struct ieee80211_key *key = rx->key; 602 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data; 603 const struct ieee80211_cipher_scheme *cs = NULL; 604 int hdrlen = ieee80211_hdrlen(hdr->frame_control); 605 struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb); 606 int data_len; 607 u8 *rx_pn; 608 u8 *skb_pn; 609 u8 qos_tid; 610 611 if (!rx->sta || !rx->sta->cipher_scheme || 612 !(status->flag & RX_FLAG_DECRYPTED)) 613 return RX_DROP_UNUSABLE; 614 615 if (!ieee80211_is_data(hdr->frame_control)) 616 return RX_CONTINUE; 617 618 cs = rx->sta->cipher_scheme; 619 620 data_len = rx->skb->len - hdrlen - cs->hdr_len; 621 622 if (data_len < 0) 623 return RX_DROP_UNUSABLE; 624 625 if (ieee80211_is_data_qos(hdr->frame_control)) 626 qos_tid = *ieee80211_get_qos_ctl(hdr) & 627 IEEE80211_QOS_CTL_TID_MASK; 628 else 629 qos_tid = 0; 630 631 if (skb_linearize(rx->skb)) 632 return RX_DROP_UNUSABLE; 633 634 hdr = (struct ieee80211_hdr *)rx->skb->data; 635 636 rx_pn = key->u.gen.rx_pn[qos_tid]; 637 skb_pn = rx->skb->data + hdrlen + cs->pn_off; 638 639 if (ieee80211_crypto_cs_pn_compare(skb_pn, rx_pn, cs->pn_len) <= 0) 640 return RX_DROP_UNUSABLE; 641 642 memcpy(rx_pn, skb_pn, cs->pn_len); 643 644 /* remove security header and MIC */ 645 if (pskb_trim(rx->skb, rx->skb->len - cs->mic_len)) 646 return RX_DROP_UNUSABLE; 647 648 memmove(rx->skb->data + cs->hdr_len, rx->skb->data, hdrlen); 649 skb_pull(rx->skb, cs->hdr_len); 650 651 return RX_CONTINUE; 652 } 653 654 static void bip_aad(struct sk_buff *skb, u8 *aad) 655 { 656 __le16 mask_fc; 657 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; 658 659 /* BIP AAD: FC(masked) || A1 || A2 || A3 */ 660 661 /* FC type/subtype */ 662 /* Mask FC Retry, PwrMgt, MoreData flags to zero */ 663 mask_fc = hdr->frame_control; 664 mask_fc &= ~cpu_to_le16(IEEE80211_FCTL_RETRY | IEEE80211_FCTL_PM | 665 IEEE80211_FCTL_MOREDATA); 666 put_unaligned(mask_fc, (__le16 *) &aad[0]); 667 /* A1 || A2 || A3 */ 668 memcpy(aad + 2, &hdr->addr1, 3 * ETH_ALEN); 669 } 670 671 672 static inline void bip_ipn_set64(u8 *d, u64 pn) 673 { 674 *d++ = pn; 675 *d++ = pn >> 8; 676 *d++ = pn >> 16; 677 *d++ = pn >> 24; 678 *d++ = pn >> 32; 679 *d = pn >> 40; 680 } 681 682 static inline void bip_ipn_swap(u8 *d, const u8 *s) 683 { 684 *d++ = s[5]; 685 *d++ = s[4]; 686 *d++ = s[3]; 687 *d++ = s[2]; 688 *d++ = s[1]; 689 *d = s[0]; 690 } 691 692 693 ieee80211_tx_result 694 ieee80211_crypto_aes_cmac_encrypt(struct ieee80211_tx_data *tx) 695 { 696 struct sk_buff *skb; 697 struct ieee80211_tx_info *info; 698 struct ieee80211_key *key = tx->key; 699 struct ieee80211_mmie *mmie; 700 u8 aad[20]; 701 u64 pn64; 702 703 if (WARN_ON(skb_queue_len(&tx->skbs) != 1)) 704 return TX_DROP; 705 706 skb = skb_peek(&tx->skbs); 707 708 info = IEEE80211_SKB_CB(skb); 709 710 if (info->control.hw_key) 711 return TX_CONTINUE; 712 713 if (WARN_ON(skb_tailroom(skb) < sizeof(*mmie))) 714 return TX_DROP; 715 716 mmie = (struct ieee80211_mmie *) skb_put(skb, sizeof(*mmie)); 717 mmie->element_id = WLAN_EID_MMIE; 718 mmie->length = sizeof(*mmie) - 2; 719 mmie->key_id = cpu_to_le16(key->conf.keyidx); 720 721 /* PN = PN + 1 */ 722 pn64 = atomic64_inc_return(&key->u.aes_cmac.tx_pn); 723 724 bip_ipn_set64(mmie->sequence_number, pn64); 725 726 bip_aad(skb, aad); 727 728 /* 729 * MIC = AES-128-CMAC(IGTK, AAD || Management Frame Body || MMIE, 64) 730 */ 731 ieee80211_aes_cmac(key->u.aes_cmac.tfm, aad, 732 skb->data + 24, skb->len - 24, mmie->mic); 733 734 return TX_CONTINUE; 735 } 736 737 738 ieee80211_rx_result 739 ieee80211_crypto_aes_cmac_decrypt(struct ieee80211_rx_data *rx) 740 { 741 struct sk_buff *skb = rx->skb; 742 struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb); 743 struct ieee80211_key *key = rx->key; 744 struct ieee80211_mmie *mmie; 745 u8 aad[20], mic[8], ipn[6]; 746 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; 747 748 if (!ieee80211_is_mgmt(hdr->frame_control)) 749 return RX_CONTINUE; 750 751 /* management frames are already linear */ 752 753 if (skb->len < 24 + sizeof(*mmie)) 754 return RX_DROP_UNUSABLE; 755 756 mmie = (struct ieee80211_mmie *) 757 (skb->data + skb->len - sizeof(*mmie)); 758 if (mmie->element_id != WLAN_EID_MMIE || 759 mmie->length != sizeof(*mmie) - 2) 760 return RX_DROP_UNUSABLE; /* Invalid MMIE */ 761 762 bip_ipn_swap(ipn, mmie->sequence_number); 763 764 if (memcmp(ipn, key->u.aes_cmac.rx_pn, 6) <= 0) { 765 key->u.aes_cmac.replays++; 766 return RX_DROP_UNUSABLE; 767 } 768 769 if (!(status->flag & RX_FLAG_DECRYPTED)) { 770 /* hardware didn't decrypt/verify MIC */ 771 bip_aad(skb, aad); 772 ieee80211_aes_cmac(key->u.aes_cmac.tfm, aad, 773 skb->data + 24, skb->len - 24, mic); 774 if (memcmp(mic, mmie->mic, sizeof(mmie->mic)) != 0) { 775 key->u.aes_cmac.icverrors++; 776 return RX_DROP_UNUSABLE; 777 } 778 } 779 780 memcpy(key->u.aes_cmac.rx_pn, ipn, 6); 781 782 /* Remove MMIE */ 783 skb_trim(skb, skb->len - sizeof(*mmie)); 784 785 return RX_CONTINUE; 786 } 787 788 ieee80211_tx_result 789 ieee80211_crypto_hw_encrypt(struct ieee80211_tx_data *tx) 790 { 791 struct sk_buff *skb; 792 struct ieee80211_tx_info *info = NULL; 793 ieee80211_tx_result res; 794 795 skb_queue_walk(&tx->skbs, skb) { 796 info = IEEE80211_SKB_CB(skb); 797 798 /* handle hw-only algorithm */ 799 if (!info->control.hw_key) 800 return TX_DROP; 801 802 if (tx->key->sta->cipher_scheme) { 803 res = ieee80211_crypto_cs_encrypt(tx, skb); 804 if (res != TX_CONTINUE) 805 return res; 806 } 807 } 808 809 ieee80211_tx_set_protected(tx); 810 811 return TX_CONTINUE; 812 } 813 814 ieee80211_rx_result 815 ieee80211_crypto_hw_decrypt(struct ieee80211_rx_data *rx) 816 { 817 if (rx->sta && rx->sta->cipher_scheme) 818 return ieee80211_crypto_cs_decrypt(rx); 819 820 return RX_DROP_UNUSABLE; 821 } 822