1 /* 2 BlueZ - Bluetooth protocol stack for Linux 3 Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies). 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 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS 10 OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 11 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF THIRD PARTY RIGHTS. 12 IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) AND AUTHOR(S) BE LIABLE FOR ANY 13 CLAIM, OR ANY SPECIAL INDIRECT OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES 14 WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 15 ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 16 OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 17 18 ALL LIABILITY, INCLUDING LIABILITY FOR INFRINGEMENT OF ANY PATENTS, 19 COPYRIGHTS, TRADEMARKS OR OTHER RIGHTS, RELATING TO USE OF THIS 20 SOFTWARE IS DISCLAIMED. 21 */ 22 23 #include <linux/crypto.h> 24 #include <linux/scatterlist.h> 25 #include <crypto/b128ops.h> 26 27 #include <net/bluetooth/bluetooth.h> 28 #include <net/bluetooth/hci_core.h> 29 #include <net/bluetooth/l2cap.h> 30 #include <net/bluetooth/mgmt.h> 31 32 #include "ecc.h" 33 #include "smp.h" 34 35 /* Low-level debug macros to be used for stuff that we don't want 36 * accidentially in dmesg, i.e. the values of the various crypto keys 37 * and the inputs & outputs of crypto functions. 38 */ 39 #ifdef DEBUG 40 #define SMP_DBG(fmt, ...) printk(KERN_DEBUG "%s: " fmt, __func__, \ 41 ##__VA_ARGS__) 42 #else 43 #define SMP_DBG(fmt, ...) no_printk(KERN_DEBUG "%s: " fmt, __func__, \ 44 ##__VA_ARGS__) 45 #endif 46 47 #define SMP_ALLOW_CMD(smp, code) set_bit(code, &smp->allow_cmd) 48 49 /* Keys which are not distributed with Secure Connections */ 50 #define SMP_SC_NO_DIST (SMP_DIST_ENC_KEY | SMP_DIST_LINK_KEY); 51 52 #define SMP_TIMEOUT msecs_to_jiffies(30000) 53 54 #define AUTH_REQ_MASK(dev) (test_bit(HCI_SC_ENABLED, &(dev)->dev_flags) ? \ 55 0x1f : 0x07) 56 #define KEY_DIST_MASK 0x07 57 58 /* Maximum message length that can be passed to aes_cmac */ 59 #define CMAC_MSG_MAX 80 60 61 enum { 62 SMP_FLAG_TK_VALID, 63 SMP_FLAG_CFM_PENDING, 64 SMP_FLAG_MITM_AUTH, 65 SMP_FLAG_COMPLETE, 66 SMP_FLAG_INITIATOR, 67 SMP_FLAG_SC, 68 SMP_FLAG_REMOTE_PK, 69 SMP_FLAG_DEBUG_KEY, 70 SMP_FLAG_WAIT_USER, 71 SMP_FLAG_DHKEY_PENDING, 72 SMP_FLAG_OOB, 73 }; 74 75 struct smp_chan { 76 struct l2cap_conn *conn; 77 struct delayed_work security_timer; 78 unsigned long allow_cmd; /* Bitmask of allowed commands */ 79 80 u8 preq[7]; /* SMP Pairing Request */ 81 u8 prsp[7]; /* SMP Pairing Response */ 82 u8 prnd[16]; /* SMP Pairing Random (local) */ 83 u8 rrnd[16]; /* SMP Pairing Random (remote) */ 84 u8 pcnf[16]; /* SMP Pairing Confirm */ 85 u8 tk[16]; /* SMP Temporary Key */ 86 u8 rr[16]; 87 u8 enc_key_size; 88 u8 remote_key_dist; 89 bdaddr_t id_addr; 90 u8 id_addr_type; 91 u8 irk[16]; 92 struct smp_csrk *csrk; 93 struct smp_csrk *slave_csrk; 94 struct smp_ltk *ltk; 95 struct smp_ltk *slave_ltk; 96 struct smp_irk *remote_irk; 97 u8 *link_key; 98 unsigned long flags; 99 u8 method; 100 u8 passkey_round; 101 102 /* Secure Connections variables */ 103 u8 local_pk[64]; 104 u8 local_sk[32]; 105 u8 remote_pk[64]; 106 u8 dhkey[32]; 107 u8 mackey[16]; 108 109 struct crypto_blkcipher *tfm_aes; 110 struct crypto_hash *tfm_cmac; 111 }; 112 113 /* These debug key values are defined in the SMP section of the core 114 * specification. debug_pk is the public debug key and debug_sk the 115 * private debug key. 116 */ 117 static const u8 debug_pk[64] = { 118 0xe6, 0x9d, 0x35, 0x0e, 0x48, 0x01, 0x03, 0xcc, 119 0xdb, 0xfd, 0xf4, 0xac, 0x11, 0x91, 0xf4, 0xef, 120 0xb9, 0xa5, 0xf9, 0xe9, 0xa7, 0x83, 0x2c, 0x5e, 121 0x2c, 0xbe, 0x97, 0xf2, 0xd2, 0x03, 0xb0, 0x20, 122 123 0x8b, 0xd2, 0x89, 0x15, 0xd0, 0x8e, 0x1c, 0x74, 124 0x24, 0x30, 0xed, 0x8f, 0xc2, 0x45, 0x63, 0x76, 125 0x5c, 0x15, 0x52, 0x5a, 0xbf, 0x9a, 0x32, 0x63, 126 0x6d, 0xeb, 0x2a, 0x65, 0x49, 0x9c, 0x80, 0xdc, 127 }; 128 129 static const u8 debug_sk[32] = { 130 0xbd, 0x1a, 0x3c, 0xcd, 0xa6, 0xb8, 0x99, 0x58, 131 0x99, 0xb7, 0x40, 0xeb, 0x7b, 0x60, 0xff, 0x4a, 132 0x50, 0x3f, 0x10, 0xd2, 0xe3, 0xb3, 0xc9, 0x74, 133 0x38, 0x5f, 0xc5, 0xa3, 0xd4, 0xf6, 0x49, 0x3f, 134 }; 135 136 static inline void swap_buf(const u8 *src, u8 *dst, size_t len) 137 { 138 size_t i; 139 140 for (i = 0; i < len; i++) 141 dst[len - 1 - i] = src[i]; 142 } 143 144 /* The following functions map to the LE SC SMP crypto functions 145 * AES-CMAC, f4, f5, f6, g2 and h6. 146 */ 147 148 static int aes_cmac(struct crypto_hash *tfm, const u8 k[16], const u8 *m, 149 size_t len, u8 mac[16]) 150 { 151 uint8_t tmp[16], mac_msb[16], msg_msb[CMAC_MSG_MAX]; 152 struct hash_desc desc; 153 struct scatterlist sg; 154 int err; 155 156 if (len > CMAC_MSG_MAX) 157 return -EFBIG; 158 159 if (!tfm) { 160 BT_ERR("tfm %p", tfm); 161 return -EINVAL; 162 } 163 164 desc.tfm = tfm; 165 desc.flags = 0; 166 167 crypto_hash_init(&desc); 168 169 /* Swap key and message from LSB to MSB */ 170 swap_buf(k, tmp, 16); 171 swap_buf(m, msg_msb, len); 172 173 SMP_DBG("msg (len %zu) %*phN", len, (int) len, m); 174 SMP_DBG("key %16phN", k); 175 176 err = crypto_hash_setkey(tfm, tmp, 16); 177 if (err) { 178 BT_ERR("cipher setkey failed: %d", err); 179 return err; 180 } 181 182 sg_init_one(&sg, msg_msb, len); 183 184 err = crypto_hash_update(&desc, &sg, len); 185 if (err) { 186 BT_ERR("Hash update error %d", err); 187 return err; 188 } 189 190 err = crypto_hash_final(&desc, mac_msb); 191 if (err) { 192 BT_ERR("Hash final error %d", err); 193 return err; 194 } 195 196 swap_buf(mac_msb, mac, 16); 197 198 SMP_DBG("mac %16phN", mac); 199 200 return 0; 201 } 202 203 static int smp_f4(struct crypto_hash *tfm_cmac, const u8 u[32], const u8 v[32], 204 const u8 x[16], u8 z, u8 res[16]) 205 { 206 u8 m[65]; 207 int err; 208 209 SMP_DBG("u %32phN", u); 210 SMP_DBG("v %32phN", v); 211 SMP_DBG("x %16phN z %02x", x, z); 212 213 m[0] = z; 214 memcpy(m + 1, v, 32); 215 memcpy(m + 33, u, 32); 216 217 err = aes_cmac(tfm_cmac, x, m, sizeof(m), res); 218 if (err) 219 return err; 220 221 SMP_DBG("res %16phN", res); 222 223 return err; 224 } 225 226 static int smp_f5(struct crypto_hash *tfm_cmac, u8 w[32], u8 n1[16], u8 n2[16], 227 u8 a1[7], u8 a2[7], u8 mackey[16], u8 ltk[16]) 228 { 229 /* The btle, salt and length "magic" values are as defined in 230 * the SMP section of the Bluetooth core specification. In ASCII 231 * the btle value ends up being 'btle'. The salt is just a 232 * random number whereas length is the value 256 in little 233 * endian format. 234 */ 235 const u8 btle[4] = { 0x65, 0x6c, 0x74, 0x62 }; 236 const u8 salt[16] = { 0xbe, 0x83, 0x60, 0x5a, 0xdb, 0x0b, 0x37, 0x60, 237 0x38, 0xa5, 0xf5, 0xaa, 0x91, 0x83, 0x88, 0x6c }; 238 const u8 length[2] = { 0x00, 0x01 }; 239 u8 m[53], t[16]; 240 int err; 241 242 SMP_DBG("w %32phN", w); 243 SMP_DBG("n1 %16phN n2 %16phN", n1, n2); 244 SMP_DBG("a1 %7phN a2 %7phN", a1, a2); 245 246 err = aes_cmac(tfm_cmac, salt, w, 32, t); 247 if (err) 248 return err; 249 250 SMP_DBG("t %16phN", t); 251 252 memcpy(m, length, 2); 253 memcpy(m + 2, a2, 7); 254 memcpy(m + 9, a1, 7); 255 memcpy(m + 16, n2, 16); 256 memcpy(m + 32, n1, 16); 257 memcpy(m + 48, btle, 4); 258 259 m[52] = 0; /* Counter */ 260 261 err = aes_cmac(tfm_cmac, t, m, sizeof(m), mackey); 262 if (err) 263 return err; 264 265 SMP_DBG("mackey %16phN", mackey); 266 267 m[52] = 1; /* Counter */ 268 269 err = aes_cmac(tfm_cmac, t, m, sizeof(m), ltk); 270 if (err) 271 return err; 272 273 SMP_DBG("ltk %16phN", ltk); 274 275 return 0; 276 } 277 278 static int smp_f6(struct crypto_hash *tfm_cmac, const u8 w[16], 279 const u8 n1[16], u8 n2[16], const u8 r[16], 280 const u8 io_cap[3], const u8 a1[7], const u8 a2[7], 281 u8 res[16]) 282 { 283 u8 m[65]; 284 int err; 285 286 SMP_DBG("w %16phN", w); 287 SMP_DBG("n1 %16phN n2 %16phN", n1, n2); 288 SMP_DBG("r %16phN io_cap %3phN a1 %7phN a2 %7phN", r, io_cap, a1, a2); 289 290 memcpy(m, a2, 7); 291 memcpy(m + 7, a1, 7); 292 memcpy(m + 14, io_cap, 3); 293 memcpy(m + 17, r, 16); 294 memcpy(m + 33, n2, 16); 295 memcpy(m + 49, n1, 16); 296 297 err = aes_cmac(tfm_cmac, w, m, sizeof(m), res); 298 if (err) 299 return err; 300 301 BT_DBG("res %16phN", res); 302 303 return err; 304 } 305 306 static int smp_g2(struct crypto_hash *tfm_cmac, const u8 u[32], const u8 v[32], 307 const u8 x[16], const u8 y[16], u32 *val) 308 { 309 u8 m[80], tmp[16]; 310 int err; 311 312 SMP_DBG("u %32phN", u); 313 SMP_DBG("v %32phN", v); 314 SMP_DBG("x %16phN y %16phN", x, y); 315 316 memcpy(m, y, 16); 317 memcpy(m + 16, v, 32); 318 memcpy(m + 48, u, 32); 319 320 err = aes_cmac(tfm_cmac, x, m, sizeof(m), tmp); 321 if (err) 322 return err; 323 324 *val = get_unaligned_le32(tmp); 325 *val %= 1000000; 326 327 SMP_DBG("val %06u", *val); 328 329 return 0; 330 } 331 332 static int smp_h6(struct crypto_hash *tfm_cmac, const u8 w[16], 333 const u8 key_id[4], u8 res[16]) 334 { 335 int err; 336 337 SMP_DBG("w %16phN key_id %4phN", w, key_id); 338 339 err = aes_cmac(tfm_cmac, w, key_id, 4, res); 340 if (err) 341 return err; 342 343 SMP_DBG("res %16phN", res); 344 345 return err; 346 } 347 348 /* The following functions map to the legacy SMP crypto functions e, c1, 349 * s1 and ah. 350 */ 351 352 static int smp_e(struct crypto_blkcipher *tfm, const u8 *k, u8 *r) 353 { 354 struct blkcipher_desc desc; 355 struct scatterlist sg; 356 uint8_t tmp[16], data[16]; 357 int err; 358 359 if (!tfm) { 360 BT_ERR("tfm %p", tfm); 361 return -EINVAL; 362 } 363 364 desc.tfm = tfm; 365 desc.flags = 0; 366 367 /* The most significant octet of key corresponds to k[0] */ 368 swap_buf(k, tmp, 16); 369 370 err = crypto_blkcipher_setkey(tfm, tmp, 16); 371 if (err) { 372 BT_ERR("cipher setkey failed: %d", err); 373 return err; 374 } 375 376 /* Most significant octet of plaintextData corresponds to data[0] */ 377 swap_buf(r, data, 16); 378 379 sg_init_one(&sg, data, 16); 380 381 err = crypto_blkcipher_encrypt(&desc, &sg, &sg, 16); 382 if (err) 383 BT_ERR("Encrypt data error %d", err); 384 385 /* Most significant octet of encryptedData corresponds to data[0] */ 386 swap_buf(data, r, 16); 387 388 return err; 389 } 390 391 static int smp_c1(struct crypto_blkcipher *tfm_aes, const u8 k[16], 392 const u8 r[16], const u8 preq[7], const u8 pres[7], u8 _iat, 393 const bdaddr_t *ia, u8 _rat, const bdaddr_t *ra, u8 res[16]) 394 { 395 u8 p1[16], p2[16]; 396 int err; 397 398 memset(p1, 0, 16); 399 400 /* p1 = pres || preq || _rat || _iat */ 401 p1[0] = _iat; 402 p1[1] = _rat; 403 memcpy(p1 + 2, preq, 7); 404 memcpy(p1 + 9, pres, 7); 405 406 /* p2 = padding || ia || ra */ 407 memcpy(p2, ra, 6); 408 memcpy(p2 + 6, ia, 6); 409 memset(p2 + 12, 0, 4); 410 411 /* res = r XOR p1 */ 412 u128_xor((u128 *) res, (u128 *) r, (u128 *) p1); 413 414 /* res = e(k, res) */ 415 err = smp_e(tfm_aes, k, res); 416 if (err) { 417 BT_ERR("Encrypt data error"); 418 return err; 419 } 420 421 /* res = res XOR p2 */ 422 u128_xor((u128 *) res, (u128 *) res, (u128 *) p2); 423 424 /* res = e(k, res) */ 425 err = smp_e(tfm_aes, k, res); 426 if (err) 427 BT_ERR("Encrypt data error"); 428 429 return err; 430 } 431 432 static int smp_s1(struct crypto_blkcipher *tfm_aes, const u8 k[16], 433 const u8 r1[16], const u8 r2[16], u8 _r[16]) 434 { 435 int err; 436 437 /* Just least significant octets from r1 and r2 are considered */ 438 memcpy(_r, r2, 8); 439 memcpy(_r + 8, r1, 8); 440 441 err = smp_e(tfm_aes, k, _r); 442 if (err) 443 BT_ERR("Encrypt data error"); 444 445 return err; 446 } 447 448 static int smp_ah(struct crypto_blkcipher *tfm, const u8 irk[16], 449 const u8 r[3], u8 res[3]) 450 { 451 u8 _res[16]; 452 int err; 453 454 /* r' = padding || r */ 455 memcpy(_res, r, 3); 456 memset(_res + 3, 0, 13); 457 458 err = smp_e(tfm, irk, _res); 459 if (err) { 460 BT_ERR("Encrypt error"); 461 return err; 462 } 463 464 /* The output of the random address function ah is: 465 * ah(h, r) = e(k, r') mod 2^24 466 * The output of the security function e is then truncated to 24 bits 467 * by taking the least significant 24 bits of the output of e as the 468 * result of ah. 469 */ 470 memcpy(res, _res, 3); 471 472 return 0; 473 } 474 475 bool smp_irk_matches(struct hci_dev *hdev, const u8 irk[16], 476 const bdaddr_t *bdaddr) 477 { 478 struct l2cap_chan *chan = hdev->smp_data; 479 struct crypto_blkcipher *tfm; 480 u8 hash[3]; 481 int err; 482 483 if (!chan || !chan->data) 484 return false; 485 486 tfm = chan->data; 487 488 BT_DBG("RPA %pMR IRK %*phN", bdaddr, 16, irk); 489 490 err = smp_ah(tfm, irk, &bdaddr->b[3], hash); 491 if (err) 492 return false; 493 494 return !memcmp(bdaddr->b, hash, 3); 495 } 496 497 int smp_generate_rpa(struct hci_dev *hdev, const u8 irk[16], bdaddr_t *rpa) 498 { 499 struct l2cap_chan *chan = hdev->smp_data; 500 struct crypto_blkcipher *tfm; 501 int err; 502 503 if (!chan || !chan->data) 504 return -EOPNOTSUPP; 505 506 tfm = chan->data; 507 508 get_random_bytes(&rpa->b[3], 3); 509 510 rpa->b[5] &= 0x3f; /* Clear two most significant bits */ 511 rpa->b[5] |= 0x40; /* Set second most significant bit */ 512 513 err = smp_ah(tfm, irk, &rpa->b[3], rpa->b); 514 if (err < 0) 515 return err; 516 517 BT_DBG("RPA %pMR", rpa); 518 519 return 0; 520 } 521 522 static void smp_send_cmd(struct l2cap_conn *conn, u8 code, u16 len, void *data) 523 { 524 struct l2cap_chan *chan = conn->smp; 525 struct smp_chan *smp; 526 struct kvec iv[2]; 527 struct msghdr msg; 528 529 if (!chan) 530 return; 531 532 BT_DBG("code 0x%2.2x", code); 533 534 iv[0].iov_base = &code; 535 iv[0].iov_len = 1; 536 537 iv[1].iov_base = data; 538 iv[1].iov_len = len; 539 540 memset(&msg, 0, sizeof(msg)); 541 542 iov_iter_kvec(&msg.msg_iter, WRITE | ITER_KVEC, iv, 2, 1 + len); 543 544 l2cap_chan_send(chan, &msg, 1 + len); 545 546 if (!chan->data) 547 return; 548 549 smp = chan->data; 550 551 cancel_delayed_work_sync(&smp->security_timer); 552 schedule_delayed_work(&smp->security_timer, SMP_TIMEOUT); 553 } 554 555 static u8 authreq_to_seclevel(u8 authreq) 556 { 557 if (authreq & SMP_AUTH_MITM) { 558 if (authreq & SMP_AUTH_SC) 559 return BT_SECURITY_FIPS; 560 else 561 return BT_SECURITY_HIGH; 562 } else { 563 return BT_SECURITY_MEDIUM; 564 } 565 } 566 567 static __u8 seclevel_to_authreq(__u8 sec_level) 568 { 569 switch (sec_level) { 570 case BT_SECURITY_FIPS: 571 case BT_SECURITY_HIGH: 572 return SMP_AUTH_MITM | SMP_AUTH_BONDING; 573 case BT_SECURITY_MEDIUM: 574 return SMP_AUTH_BONDING; 575 default: 576 return SMP_AUTH_NONE; 577 } 578 } 579 580 static void build_pairing_cmd(struct l2cap_conn *conn, 581 struct smp_cmd_pairing *req, 582 struct smp_cmd_pairing *rsp, __u8 authreq) 583 { 584 struct l2cap_chan *chan = conn->smp; 585 struct smp_chan *smp = chan->data; 586 struct hci_conn *hcon = conn->hcon; 587 struct hci_dev *hdev = hcon->hdev; 588 u8 local_dist = 0, remote_dist = 0, oob_flag = SMP_OOB_NOT_PRESENT; 589 590 if (test_bit(HCI_BONDABLE, &conn->hcon->hdev->dev_flags)) { 591 local_dist = SMP_DIST_ENC_KEY | SMP_DIST_SIGN; 592 remote_dist = SMP_DIST_ENC_KEY | SMP_DIST_SIGN; 593 authreq |= SMP_AUTH_BONDING; 594 } else { 595 authreq &= ~SMP_AUTH_BONDING; 596 } 597 598 if (test_bit(HCI_RPA_RESOLVING, &hdev->dev_flags)) 599 remote_dist |= SMP_DIST_ID_KEY; 600 601 if (test_bit(HCI_PRIVACY, &hdev->dev_flags)) 602 local_dist |= SMP_DIST_ID_KEY; 603 604 if (test_bit(HCI_SC_ENABLED, &hdev->dev_flags) && 605 (authreq & SMP_AUTH_SC)) { 606 struct oob_data *oob_data; 607 u8 bdaddr_type; 608 609 if (test_bit(HCI_SSP_ENABLED, &hdev->dev_flags)) { 610 local_dist |= SMP_DIST_LINK_KEY; 611 remote_dist |= SMP_DIST_LINK_KEY; 612 } 613 614 if (hcon->dst_type == ADDR_LE_DEV_PUBLIC) 615 bdaddr_type = BDADDR_LE_PUBLIC; 616 else 617 bdaddr_type = BDADDR_LE_RANDOM; 618 619 oob_data = hci_find_remote_oob_data(hdev, &hcon->dst, 620 bdaddr_type); 621 if (oob_data) { 622 set_bit(SMP_FLAG_OOB, &smp->flags); 623 oob_flag = SMP_OOB_PRESENT; 624 memcpy(smp->rr, oob_data->rand256, 16); 625 memcpy(smp->pcnf, oob_data->hash256, 16); 626 } 627 628 } else { 629 authreq &= ~SMP_AUTH_SC; 630 } 631 632 if (rsp == NULL) { 633 req->io_capability = conn->hcon->io_capability; 634 req->oob_flag = oob_flag; 635 req->max_key_size = SMP_MAX_ENC_KEY_SIZE; 636 req->init_key_dist = local_dist; 637 req->resp_key_dist = remote_dist; 638 req->auth_req = (authreq & AUTH_REQ_MASK(hdev)); 639 640 smp->remote_key_dist = remote_dist; 641 return; 642 } 643 644 rsp->io_capability = conn->hcon->io_capability; 645 rsp->oob_flag = oob_flag; 646 rsp->max_key_size = SMP_MAX_ENC_KEY_SIZE; 647 rsp->init_key_dist = req->init_key_dist & remote_dist; 648 rsp->resp_key_dist = req->resp_key_dist & local_dist; 649 rsp->auth_req = (authreq & AUTH_REQ_MASK(hdev)); 650 651 smp->remote_key_dist = rsp->init_key_dist; 652 } 653 654 static u8 check_enc_key_size(struct l2cap_conn *conn, __u8 max_key_size) 655 { 656 struct l2cap_chan *chan = conn->smp; 657 struct smp_chan *smp = chan->data; 658 659 if ((max_key_size > SMP_MAX_ENC_KEY_SIZE) || 660 (max_key_size < SMP_MIN_ENC_KEY_SIZE)) 661 return SMP_ENC_KEY_SIZE; 662 663 smp->enc_key_size = max_key_size; 664 665 return 0; 666 } 667 668 static void smp_chan_destroy(struct l2cap_conn *conn) 669 { 670 struct l2cap_chan *chan = conn->smp; 671 struct smp_chan *smp = chan->data; 672 struct hci_conn *hcon = conn->hcon; 673 bool complete; 674 675 BUG_ON(!smp); 676 677 cancel_delayed_work_sync(&smp->security_timer); 678 679 complete = test_bit(SMP_FLAG_COMPLETE, &smp->flags); 680 mgmt_smp_complete(hcon, complete); 681 682 kfree(smp->csrk); 683 kfree(smp->slave_csrk); 684 kfree(smp->link_key); 685 686 crypto_free_blkcipher(smp->tfm_aes); 687 crypto_free_hash(smp->tfm_cmac); 688 689 /* Ensure that we don't leave any debug key around if debug key 690 * support hasn't been explicitly enabled. 691 */ 692 if (smp->ltk && smp->ltk->type == SMP_LTK_P256_DEBUG && 693 !test_bit(HCI_KEEP_DEBUG_KEYS, &hcon->hdev->dev_flags)) { 694 list_del_rcu(&smp->ltk->list); 695 kfree_rcu(smp->ltk, rcu); 696 smp->ltk = NULL; 697 } 698 699 /* If pairing failed clean up any keys we might have */ 700 if (!complete) { 701 if (smp->ltk) { 702 list_del_rcu(&smp->ltk->list); 703 kfree_rcu(smp->ltk, rcu); 704 } 705 706 if (smp->slave_ltk) { 707 list_del_rcu(&smp->slave_ltk->list); 708 kfree_rcu(smp->slave_ltk, rcu); 709 } 710 711 if (smp->remote_irk) { 712 list_del_rcu(&smp->remote_irk->list); 713 kfree_rcu(smp->remote_irk, rcu); 714 } 715 } 716 717 chan->data = NULL; 718 kfree(smp); 719 hci_conn_drop(hcon); 720 } 721 722 static void smp_failure(struct l2cap_conn *conn, u8 reason) 723 { 724 struct hci_conn *hcon = conn->hcon; 725 struct l2cap_chan *chan = conn->smp; 726 727 if (reason) 728 smp_send_cmd(conn, SMP_CMD_PAIRING_FAIL, sizeof(reason), 729 &reason); 730 731 clear_bit(HCI_CONN_ENCRYPT_PEND, &hcon->flags); 732 mgmt_auth_failed(hcon, HCI_ERROR_AUTH_FAILURE); 733 734 if (chan->data) 735 smp_chan_destroy(conn); 736 } 737 738 #define JUST_WORKS 0x00 739 #define JUST_CFM 0x01 740 #define REQ_PASSKEY 0x02 741 #define CFM_PASSKEY 0x03 742 #define REQ_OOB 0x04 743 #define DSP_PASSKEY 0x05 744 #define OVERLAP 0xFF 745 746 static const u8 gen_method[5][5] = { 747 { JUST_WORKS, JUST_CFM, REQ_PASSKEY, JUST_WORKS, REQ_PASSKEY }, 748 { JUST_WORKS, JUST_CFM, REQ_PASSKEY, JUST_WORKS, REQ_PASSKEY }, 749 { CFM_PASSKEY, CFM_PASSKEY, REQ_PASSKEY, JUST_WORKS, CFM_PASSKEY }, 750 { JUST_WORKS, JUST_CFM, JUST_WORKS, JUST_WORKS, JUST_CFM }, 751 { CFM_PASSKEY, CFM_PASSKEY, REQ_PASSKEY, JUST_WORKS, OVERLAP }, 752 }; 753 754 static const u8 sc_method[5][5] = { 755 { JUST_WORKS, JUST_CFM, REQ_PASSKEY, JUST_WORKS, REQ_PASSKEY }, 756 { JUST_WORKS, CFM_PASSKEY, REQ_PASSKEY, JUST_WORKS, CFM_PASSKEY }, 757 { DSP_PASSKEY, DSP_PASSKEY, REQ_PASSKEY, JUST_WORKS, DSP_PASSKEY }, 758 { JUST_WORKS, JUST_CFM, JUST_WORKS, JUST_WORKS, JUST_CFM }, 759 { DSP_PASSKEY, CFM_PASSKEY, REQ_PASSKEY, JUST_WORKS, CFM_PASSKEY }, 760 }; 761 762 static u8 get_auth_method(struct smp_chan *smp, u8 local_io, u8 remote_io) 763 { 764 /* If either side has unknown io_caps, use JUST_CFM (which gets 765 * converted later to JUST_WORKS if we're initiators. 766 */ 767 if (local_io > SMP_IO_KEYBOARD_DISPLAY || 768 remote_io > SMP_IO_KEYBOARD_DISPLAY) 769 return JUST_CFM; 770 771 if (test_bit(SMP_FLAG_SC, &smp->flags)) 772 return sc_method[remote_io][local_io]; 773 774 return gen_method[remote_io][local_io]; 775 } 776 777 static int tk_request(struct l2cap_conn *conn, u8 remote_oob, u8 auth, 778 u8 local_io, u8 remote_io) 779 { 780 struct hci_conn *hcon = conn->hcon; 781 struct l2cap_chan *chan = conn->smp; 782 struct smp_chan *smp = chan->data; 783 u32 passkey = 0; 784 int ret = 0; 785 786 /* Initialize key for JUST WORKS */ 787 memset(smp->tk, 0, sizeof(smp->tk)); 788 clear_bit(SMP_FLAG_TK_VALID, &smp->flags); 789 790 BT_DBG("tk_request: auth:%d lcl:%d rem:%d", auth, local_io, remote_io); 791 792 /* If neither side wants MITM, either "just" confirm an incoming 793 * request or use just-works for outgoing ones. The JUST_CFM 794 * will be converted to JUST_WORKS if necessary later in this 795 * function. If either side has MITM look up the method from the 796 * table. 797 */ 798 if (!(auth & SMP_AUTH_MITM)) 799 smp->method = JUST_CFM; 800 else 801 smp->method = get_auth_method(smp, local_io, remote_io); 802 803 /* Don't confirm locally initiated pairing attempts */ 804 if (smp->method == JUST_CFM && test_bit(SMP_FLAG_INITIATOR, 805 &smp->flags)) 806 smp->method = JUST_WORKS; 807 808 /* Don't bother user space with no IO capabilities */ 809 if (smp->method == JUST_CFM && 810 hcon->io_capability == HCI_IO_NO_INPUT_OUTPUT) 811 smp->method = JUST_WORKS; 812 813 /* If Just Works, Continue with Zero TK */ 814 if (smp->method == JUST_WORKS) { 815 set_bit(SMP_FLAG_TK_VALID, &smp->flags); 816 return 0; 817 } 818 819 /* Not Just Works/Confirm results in MITM Authentication */ 820 if (smp->method != JUST_CFM) { 821 set_bit(SMP_FLAG_MITM_AUTH, &smp->flags); 822 if (hcon->pending_sec_level < BT_SECURITY_HIGH) 823 hcon->pending_sec_level = BT_SECURITY_HIGH; 824 } 825 826 /* If both devices have Keyoard-Display I/O, the master 827 * Confirms and the slave Enters the passkey. 828 */ 829 if (smp->method == OVERLAP) { 830 if (hcon->role == HCI_ROLE_MASTER) 831 smp->method = CFM_PASSKEY; 832 else 833 smp->method = REQ_PASSKEY; 834 } 835 836 /* Generate random passkey. */ 837 if (smp->method == CFM_PASSKEY) { 838 memset(smp->tk, 0, sizeof(smp->tk)); 839 get_random_bytes(&passkey, sizeof(passkey)); 840 passkey %= 1000000; 841 put_unaligned_le32(passkey, smp->tk); 842 BT_DBG("PassKey: %d", passkey); 843 set_bit(SMP_FLAG_TK_VALID, &smp->flags); 844 } 845 846 if (smp->method == REQ_PASSKEY) 847 ret = mgmt_user_passkey_request(hcon->hdev, &hcon->dst, 848 hcon->type, hcon->dst_type); 849 else if (smp->method == JUST_CFM) 850 ret = mgmt_user_confirm_request(hcon->hdev, &hcon->dst, 851 hcon->type, hcon->dst_type, 852 passkey, 1); 853 else 854 ret = mgmt_user_passkey_notify(hcon->hdev, &hcon->dst, 855 hcon->type, hcon->dst_type, 856 passkey, 0); 857 858 return ret; 859 } 860 861 static u8 smp_confirm(struct smp_chan *smp) 862 { 863 struct l2cap_conn *conn = smp->conn; 864 struct smp_cmd_pairing_confirm cp; 865 int ret; 866 867 BT_DBG("conn %p", conn); 868 869 ret = smp_c1(smp->tfm_aes, smp->tk, smp->prnd, smp->preq, smp->prsp, 870 conn->hcon->init_addr_type, &conn->hcon->init_addr, 871 conn->hcon->resp_addr_type, &conn->hcon->resp_addr, 872 cp.confirm_val); 873 if (ret) 874 return SMP_UNSPECIFIED; 875 876 clear_bit(SMP_FLAG_CFM_PENDING, &smp->flags); 877 878 smp_send_cmd(smp->conn, SMP_CMD_PAIRING_CONFIRM, sizeof(cp), &cp); 879 880 if (conn->hcon->out) 881 SMP_ALLOW_CMD(smp, SMP_CMD_PAIRING_CONFIRM); 882 else 883 SMP_ALLOW_CMD(smp, SMP_CMD_PAIRING_RANDOM); 884 885 return 0; 886 } 887 888 static u8 smp_random(struct smp_chan *smp) 889 { 890 struct l2cap_conn *conn = smp->conn; 891 struct hci_conn *hcon = conn->hcon; 892 u8 confirm[16]; 893 int ret; 894 895 if (IS_ERR_OR_NULL(smp->tfm_aes)) 896 return SMP_UNSPECIFIED; 897 898 BT_DBG("conn %p %s", conn, conn->hcon->out ? "master" : "slave"); 899 900 ret = smp_c1(smp->tfm_aes, smp->tk, smp->rrnd, smp->preq, smp->prsp, 901 hcon->init_addr_type, &hcon->init_addr, 902 hcon->resp_addr_type, &hcon->resp_addr, confirm); 903 if (ret) 904 return SMP_UNSPECIFIED; 905 906 if (memcmp(smp->pcnf, confirm, sizeof(smp->pcnf)) != 0) { 907 BT_ERR("Pairing failed (confirmation values mismatch)"); 908 return SMP_CONFIRM_FAILED; 909 } 910 911 if (hcon->out) { 912 u8 stk[16]; 913 __le64 rand = 0; 914 __le16 ediv = 0; 915 916 smp_s1(smp->tfm_aes, smp->tk, smp->rrnd, smp->prnd, stk); 917 918 memset(stk + smp->enc_key_size, 0, 919 SMP_MAX_ENC_KEY_SIZE - smp->enc_key_size); 920 921 if (test_and_set_bit(HCI_CONN_ENCRYPT_PEND, &hcon->flags)) 922 return SMP_UNSPECIFIED; 923 924 hci_le_start_enc(hcon, ediv, rand, stk); 925 hcon->enc_key_size = smp->enc_key_size; 926 set_bit(HCI_CONN_STK_ENCRYPT, &hcon->flags); 927 } else { 928 u8 stk[16], auth; 929 __le64 rand = 0; 930 __le16 ediv = 0; 931 932 smp_send_cmd(conn, SMP_CMD_PAIRING_RANDOM, sizeof(smp->prnd), 933 smp->prnd); 934 935 smp_s1(smp->tfm_aes, smp->tk, smp->prnd, smp->rrnd, stk); 936 937 memset(stk + smp->enc_key_size, 0, 938 SMP_MAX_ENC_KEY_SIZE - smp->enc_key_size); 939 940 if (hcon->pending_sec_level == BT_SECURITY_HIGH) 941 auth = 1; 942 else 943 auth = 0; 944 945 /* Even though there's no _SLAVE suffix this is the 946 * slave STK we're adding for later lookup (the master 947 * STK never needs to be stored). 948 */ 949 hci_add_ltk(hcon->hdev, &hcon->dst, hcon->dst_type, 950 SMP_STK, auth, stk, smp->enc_key_size, ediv, rand); 951 } 952 953 return 0; 954 } 955 956 static void smp_notify_keys(struct l2cap_conn *conn) 957 { 958 struct l2cap_chan *chan = conn->smp; 959 struct smp_chan *smp = chan->data; 960 struct hci_conn *hcon = conn->hcon; 961 struct hci_dev *hdev = hcon->hdev; 962 struct smp_cmd_pairing *req = (void *) &smp->preq[1]; 963 struct smp_cmd_pairing *rsp = (void *) &smp->prsp[1]; 964 bool persistent; 965 966 if (smp->remote_irk) { 967 mgmt_new_irk(hdev, smp->remote_irk); 968 /* Now that user space can be considered to know the 969 * identity address track the connection based on it 970 * from now on (assuming this is an LE link). 971 */ 972 if (hcon->type == LE_LINK) { 973 bacpy(&hcon->dst, &smp->remote_irk->bdaddr); 974 hcon->dst_type = smp->remote_irk->addr_type; 975 queue_work(hdev->workqueue, &conn->id_addr_update_work); 976 } 977 978 /* When receiving an indentity resolving key for 979 * a remote device that does not use a resolvable 980 * private address, just remove the key so that 981 * it is possible to use the controller white 982 * list for scanning. 983 * 984 * Userspace will have been told to not store 985 * this key at this point. So it is safe to 986 * just remove it. 987 */ 988 if (!bacmp(&smp->remote_irk->rpa, BDADDR_ANY)) { 989 list_del_rcu(&smp->remote_irk->list); 990 kfree_rcu(smp->remote_irk, rcu); 991 smp->remote_irk = NULL; 992 } 993 } 994 995 if (hcon->type == ACL_LINK) { 996 if (hcon->key_type == HCI_LK_DEBUG_COMBINATION) 997 persistent = false; 998 else 999 persistent = !test_bit(HCI_CONN_FLUSH_KEY, 1000 &hcon->flags); 1001 } else { 1002 /* The LTKs and CSRKs should be persistent only if both sides 1003 * had the bonding bit set in their authentication requests. 1004 */ 1005 persistent = !!((req->auth_req & rsp->auth_req) & 1006 SMP_AUTH_BONDING); 1007 } 1008 1009 1010 if (smp->csrk) { 1011 smp->csrk->bdaddr_type = hcon->dst_type; 1012 bacpy(&smp->csrk->bdaddr, &hcon->dst); 1013 mgmt_new_csrk(hdev, smp->csrk, persistent); 1014 } 1015 1016 if (smp->slave_csrk) { 1017 smp->slave_csrk->bdaddr_type = hcon->dst_type; 1018 bacpy(&smp->slave_csrk->bdaddr, &hcon->dst); 1019 mgmt_new_csrk(hdev, smp->slave_csrk, persistent); 1020 } 1021 1022 if (smp->ltk) { 1023 smp->ltk->bdaddr_type = hcon->dst_type; 1024 bacpy(&smp->ltk->bdaddr, &hcon->dst); 1025 mgmt_new_ltk(hdev, smp->ltk, persistent); 1026 } 1027 1028 if (smp->slave_ltk) { 1029 smp->slave_ltk->bdaddr_type = hcon->dst_type; 1030 bacpy(&smp->slave_ltk->bdaddr, &hcon->dst); 1031 mgmt_new_ltk(hdev, smp->slave_ltk, persistent); 1032 } 1033 1034 if (smp->link_key) { 1035 struct link_key *key; 1036 u8 type; 1037 1038 if (test_bit(SMP_FLAG_DEBUG_KEY, &smp->flags)) 1039 type = HCI_LK_DEBUG_COMBINATION; 1040 else if (hcon->sec_level == BT_SECURITY_FIPS) 1041 type = HCI_LK_AUTH_COMBINATION_P256; 1042 else 1043 type = HCI_LK_UNAUTH_COMBINATION_P256; 1044 1045 key = hci_add_link_key(hdev, smp->conn->hcon, &hcon->dst, 1046 smp->link_key, type, 0, &persistent); 1047 if (key) { 1048 mgmt_new_link_key(hdev, key, persistent); 1049 1050 /* Don't keep debug keys around if the relevant 1051 * flag is not set. 1052 */ 1053 if (!test_bit(HCI_KEEP_DEBUG_KEYS, &hdev->dev_flags) && 1054 key->type == HCI_LK_DEBUG_COMBINATION) { 1055 list_del_rcu(&key->list); 1056 kfree_rcu(key, rcu); 1057 } 1058 } 1059 } 1060 } 1061 1062 static void sc_add_ltk(struct smp_chan *smp) 1063 { 1064 struct hci_conn *hcon = smp->conn->hcon; 1065 u8 key_type, auth; 1066 1067 if (test_bit(SMP_FLAG_DEBUG_KEY, &smp->flags)) 1068 key_type = SMP_LTK_P256_DEBUG; 1069 else 1070 key_type = SMP_LTK_P256; 1071 1072 if (hcon->pending_sec_level == BT_SECURITY_FIPS) 1073 auth = 1; 1074 else 1075 auth = 0; 1076 1077 memset(smp->tk + smp->enc_key_size, 0, 1078 SMP_MAX_ENC_KEY_SIZE - smp->enc_key_size); 1079 1080 smp->ltk = hci_add_ltk(hcon->hdev, &hcon->dst, hcon->dst_type, 1081 key_type, auth, smp->tk, smp->enc_key_size, 1082 0, 0); 1083 } 1084 1085 static void sc_generate_link_key(struct smp_chan *smp) 1086 { 1087 /* These constants are as specified in the core specification. 1088 * In ASCII they spell out to 'tmp1' and 'lebr'. 1089 */ 1090 const u8 tmp1[4] = { 0x31, 0x70, 0x6d, 0x74 }; 1091 const u8 lebr[4] = { 0x72, 0x62, 0x65, 0x6c }; 1092 1093 smp->link_key = kzalloc(16, GFP_KERNEL); 1094 if (!smp->link_key) 1095 return; 1096 1097 if (smp_h6(smp->tfm_cmac, smp->tk, tmp1, smp->link_key)) { 1098 kfree(smp->link_key); 1099 smp->link_key = NULL; 1100 return; 1101 } 1102 1103 if (smp_h6(smp->tfm_cmac, smp->link_key, lebr, smp->link_key)) { 1104 kfree(smp->link_key); 1105 smp->link_key = NULL; 1106 return; 1107 } 1108 } 1109 1110 static void smp_allow_key_dist(struct smp_chan *smp) 1111 { 1112 /* Allow the first expected phase 3 PDU. The rest of the PDUs 1113 * will be allowed in each PDU handler to ensure we receive 1114 * them in the correct order. 1115 */ 1116 if (smp->remote_key_dist & SMP_DIST_ENC_KEY) 1117 SMP_ALLOW_CMD(smp, SMP_CMD_ENCRYPT_INFO); 1118 else if (smp->remote_key_dist & SMP_DIST_ID_KEY) 1119 SMP_ALLOW_CMD(smp, SMP_CMD_IDENT_INFO); 1120 else if (smp->remote_key_dist & SMP_DIST_SIGN) 1121 SMP_ALLOW_CMD(smp, SMP_CMD_SIGN_INFO); 1122 } 1123 1124 static void sc_generate_ltk(struct smp_chan *smp) 1125 { 1126 /* These constants are as specified in the core specification. 1127 * In ASCII they spell out to 'tmp2' and 'brle'. 1128 */ 1129 const u8 tmp2[4] = { 0x32, 0x70, 0x6d, 0x74 }; 1130 const u8 brle[4] = { 0x65, 0x6c, 0x72, 0x62 }; 1131 struct hci_conn *hcon = smp->conn->hcon; 1132 struct hci_dev *hdev = hcon->hdev; 1133 struct link_key *key; 1134 1135 key = hci_find_link_key(hdev, &hcon->dst); 1136 if (!key) { 1137 BT_ERR("%s No Link Key found to generate LTK", hdev->name); 1138 return; 1139 } 1140 1141 if (key->type == HCI_LK_DEBUG_COMBINATION) 1142 set_bit(SMP_FLAG_DEBUG_KEY, &smp->flags); 1143 1144 if (smp_h6(smp->tfm_cmac, key->val, tmp2, smp->tk)) 1145 return; 1146 1147 if (smp_h6(smp->tfm_cmac, smp->tk, brle, smp->tk)) 1148 return; 1149 1150 sc_add_ltk(smp); 1151 } 1152 1153 static void smp_distribute_keys(struct smp_chan *smp) 1154 { 1155 struct smp_cmd_pairing *req, *rsp; 1156 struct l2cap_conn *conn = smp->conn; 1157 struct hci_conn *hcon = conn->hcon; 1158 struct hci_dev *hdev = hcon->hdev; 1159 __u8 *keydist; 1160 1161 BT_DBG("conn %p", conn); 1162 1163 rsp = (void *) &smp->prsp[1]; 1164 1165 /* The responder sends its keys first */ 1166 if (hcon->out && (smp->remote_key_dist & KEY_DIST_MASK)) { 1167 smp_allow_key_dist(smp); 1168 return; 1169 } 1170 1171 req = (void *) &smp->preq[1]; 1172 1173 if (hcon->out) { 1174 keydist = &rsp->init_key_dist; 1175 *keydist &= req->init_key_dist; 1176 } else { 1177 keydist = &rsp->resp_key_dist; 1178 *keydist &= req->resp_key_dist; 1179 } 1180 1181 if (test_bit(SMP_FLAG_SC, &smp->flags)) { 1182 if (hcon->type == LE_LINK && (*keydist & SMP_DIST_LINK_KEY)) 1183 sc_generate_link_key(smp); 1184 if (hcon->type == ACL_LINK && (*keydist & SMP_DIST_ENC_KEY)) 1185 sc_generate_ltk(smp); 1186 1187 /* Clear the keys which are generated but not distributed */ 1188 *keydist &= ~SMP_SC_NO_DIST; 1189 } 1190 1191 BT_DBG("keydist 0x%x", *keydist); 1192 1193 if (*keydist & SMP_DIST_ENC_KEY) { 1194 struct smp_cmd_encrypt_info enc; 1195 struct smp_cmd_master_ident ident; 1196 struct smp_ltk *ltk; 1197 u8 authenticated; 1198 __le16 ediv; 1199 __le64 rand; 1200 1201 get_random_bytes(enc.ltk, sizeof(enc.ltk)); 1202 get_random_bytes(&ediv, sizeof(ediv)); 1203 get_random_bytes(&rand, sizeof(rand)); 1204 1205 smp_send_cmd(conn, SMP_CMD_ENCRYPT_INFO, sizeof(enc), &enc); 1206 1207 authenticated = hcon->sec_level == BT_SECURITY_HIGH; 1208 ltk = hci_add_ltk(hdev, &hcon->dst, hcon->dst_type, 1209 SMP_LTK_SLAVE, authenticated, enc.ltk, 1210 smp->enc_key_size, ediv, rand); 1211 smp->slave_ltk = ltk; 1212 1213 ident.ediv = ediv; 1214 ident.rand = rand; 1215 1216 smp_send_cmd(conn, SMP_CMD_MASTER_IDENT, sizeof(ident), &ident); 1217 1218 *keydist &= ~SMP_DIST_ENC_KEY; 1219 } 1220 1221 if (*keydist & SMP_DIST_ID_KEY) { 1222 struct smp_cmd_ident_addr_info addrinfo; 1223 struct smp_cmd_ident_info idinfo; 1224 1225 memcpy(idinfo.irk, hdev->irk, sizeof(idinfo.irk)); 1226 1227 smp_send_cmd(conn, SMP_CMD_IDENT_INFO, sizeof(idinfo), &idinfo); 1228 1229 /* The hci_conn contains the local identity address 1230 * after the connection has been established. 1231 * 1232 * This is true even when the connection has been 1233 * established using a resolvable random address. 1234 */ 1235 bacpy(&addrinfo.bdaddr, &hcon->src); 1236 addrinfo.addr_type = hcon->src_type; 1237 1238 smp_send_cmd(conn, SMP_CMD_IDENT_ADDR_INFO, sizeof(addrinfo), 1239 &addrinfo); 1240 1241 *keydist &= ~SMP_DIST_ID_KEY; 1242 } 1243 1244 if (*keydist & SMP_DIST_SIGN) { 1245 struct smp_cmd_sign_info sign; 1246 struct smp_csrk *csrk; 1247 1248 /* Generate a new random key */ 1249 get_random_bytes(sign.csrk, sizeof(sign.csrk)); 1250 1251 csrk = kzalloc(sizeof(*csrk), GFP_KERNEL); 1252 if (csrk) { 1253 csrk->master = 0x00; 1254 memcpy(csrk->val, sign.csrk, sizeof(csrk->val)); 1255 } 1256 smp->slave_csrk = csrk; 1257 1258 smp_send_cmd(conn, SMP_CMD_SIGN_INFO, sizeof(sign), &sign); 1259 1260 *keydist &= ~SMP_DIST_SIGN; 1261 } 1262 1263 /* If there are still keys to be received wait for them */ 1264 if (smp->remote_key_dist & KEY_DIST_MASK) { 1265 smp_allow_key_dist(smp); 1266 return; 1267 } 1268 1269 set_bit(SMP_FLAG_COMPLETE, &smp->flags); 1270 smp_notify_keys(conn); 1271 1272 smp_chan_destroy(conn); 1273 } 1274 1275 static void smp_timeout(struct work_struct *work) 1276 { 1277 struct smp_chan *smp = container_of(work, struct smp_chan, 1278 security_timer.work); 1279 struct l2cap_conn *conn = smp->conn; 1280 1281 BT_DBG("conn %p", conn); 1282 1283 hci_disconnect(conn->hcon, HCI_ERROR_REMOTE_USER_TERM); 1284 } 1285 1286 static struct smp_chan *smp_chan_create(struct l2cap_conn *conn) 1287 { 1288 struct l2cap_chan *chan = conn->smp; 1289 struct smp_chan *smp; 1290 1291 smp = kzalloc(sizeof(*smp), GFP_ATOMIC); 1292 if (!smp) 1293 return NULL; 1294 1295 smp->tfm_aes = crypto_alloc_blkcipher("ecb(aes)", 0, CRYPTO_ALG_ASYNC); 1296 if (IS_ERR(smp->tfm_aes)) { 1297 BT_ERR("Unable to create ECB crypto context"); 1298 kfree(smp); 1299 return NULL; 1300 } 1301 1302 smp->tfm_cmac = crypto_alloc_hash("cmac(aes)", 0, CRYPTO_ALG_ASYNC); 1303 if (IS_ERR(smp->tfm_cmac)) { 1304 BT_ERR("Unable to create CMAC crypto context"); 1305 crypto_free_blkcipher(smp->tfm_aes); 1306 kfree(smp); 1307 return NULL; 1308 } 1309 1310 smp->conn = conn; 1311 chan->data = smp; 1312 1313 SMP_ALLOW_CMD(smp, SMP_CMD_PAIRING_FAIL); 1314 1315 INIT_DELAYED_WORK(&smp->security_timer, smp_timeout); 1316 1317 hci_conn_hold(conn->hcon); 1318 1319 return smp; 1320 } 1321 1322 static int sc_mackey_and_ltk(struct smp_chan *smp, u8 mackey[16], u8 ltk[16]) 1323 { 1324 struct hci_conn *hcon = smp->conn->hcon; 1325 u8 *na, *nb, a[7], b[7]; 1326 1327 if (hcon->out) { 1328 na = smp->prnd; 1329 nb = smp->rrnd; 1330 } else { 1331 na = smp->rrnd; 1332 nb = smp->prnd; 1333 } 1334 1335 memcpy(a, &hcon->init_addr, 6); 1336 memcpy(b, &hcon->resp_addr, 6); 1337 a[6] = hcon->init_addr_type; 1338 b[6] = hcon->resp_addr_type; 1339 1340 return smp_f5(smp->tfm_cmac, smp->dhkey, na, nb, a, b, mackey, ltk); 1341 } 1342 1343 static void sc_dhkey_check(struct smp_chan *smp) 1344 { 1345 struct hci_conn *hcon = smp->conn->hcon; 1346 struct smp_cmd_dhkey_check check; 1347 u8 a[7], b[7], *local_addr, *remote_addr; 1348 u8 io_cap[3], r[16]; 1349 1350 memcpy(a, &hcon->init_addr, 6); 1351 memcpy(b, &hcon->resp_addr, 6); 1352 a[6] = hcon->init_addr_type; 1353 b[6] = hcon->resp_addr_type; 1354 1355 if (hcon->out) { 1356 local_addr = a; 1357 remote_addr = b; 1358 memcpy(io_cap, &smp->preq[1], 3); 1359 } else { 1360 local_addr = b; 1361 remote_addr = a; 1362 memcpy(io_cap, &smp->prsp[1], 3); 1363 } 1364 1365 memset(r, 0, sizeof(r)); 1366 1367 if (smp->method == REQ_PASSKEY || smp->method == DSP_PASSKEY) 1368 put_unaligned_le32(hcon->passkey_notify, r); 1369 1370 if (smp->method == REQ_OOB) 1371 memcpy(r, smp->rr, 16); 1372 1373 smp_f6(smp->tfm_cmac, smp->mackey, smp->prnd, smp->rrnd, r, io_cap, 1374 local_addr, remote_addr, check.e); 1375 1376 smp_send_cmd(smp->conn, SMP_CMD_DHKEY_CHECK, sizeof(check), &check); 1377 } 1378 1379 static u8 sc_passkey_send_confirm(struct smp_chan *smp) 1380 { 1381 struct l2cap_conn *conn = smp->conn; 1382 struct hci_conn *hcon = conn->hcon; 1383 struct smp_cmd_pairing_confirm cfm; 1384 u8 r; 1385 1386 r = ((hcon->passkey_notify >> smp->passkey_round) & 0x01); 1387 r |= 0x80; 1388 1389 get_random_bytes(smp->prnd, sizeof(smp->prnd)); 1390 1391 if (smp_f4(smp->tfm_cmac, smp->local_pk, smp->remote_pk, smp->prnd, r, 1392 cfm.confirm_val)) 1393 return SMP_UNSPECIFIED; 1394 1395 smp_send_cmd(conn, SMP_CMD_PAIRING_CONFIRM, sizeof(cfm), &cfm); 1396 1397 return 0; 1398 } 1399 1400 static u8 sc_passkey_round(struct smp_chan *smp, u8 smp_op) 1401 { 1402 struct l2cap_conn *conn = smp->conn; 1403 struct hci_conn *hcon = conn->hcon; 1404 struct hci_dev *hdev = hcon->hdev; 1405 u8 cfm[16], r; 1406 1407 /* Ignore the PDU if we've already done 20 rounds (0 - 19) */ 1408 if (smp->passkey_round >= 20) 1409 return 0; 1410 1411 switch (smp_op) { 1412 case SMP_CMD_PAIRING_RANDOM: 1413 r = ((hcon->passkey_notify >> smp->passkey_round) & 0x01); 1414 r |= 0x80; 1415 1416 if (smp_f4(smp->tfm_cmac, smp->remote_pk, smp->local_pk, 1417 smp->rrnd, r, cfm)) 1418 return SMP_UNSPECIFIED; 1419 1420 if (memcmp(smp->pcnf, cfm, 16)) 1421 return SMP_CONFIRM_FAILED; 1422 1423 smp->passkey_round++; 1424 1425 if (smp->passkey_round == 20) { 1426 /* Generate MacKey and LTK */ 1427 if (sc_mackey_and_ltk(smp, smp->mackey, smp->tk)) 1428 return SMP_UNSPECIFIED; 1429 } 1430 1431 /* The round is only complete when the initiator 1432 * receives pairing random. 1433 */ 1434 if (!hcon->out) { 1435 smp_send_cmd(conn, SMP_CMD_PAIRING_RANDOM, 1436 sizeof(smp->prnd), smp->prnd); 1437 if (smp->passkey_round == 20) 1438 SMP_ALLOW_CMD(smp, SMP_CMD_DHKEY_CHECK); 1439 else 1440 SMP_ALLOW_CMD(smp, SMP_CMD_PAIRING_CONFIRM); 1441 return 0; 1442 } 1443 1444 /* Start the next round */ 1445 if (smp->passkey_round != 20) 1446 return sc_passkey_round(smp, 0); 1447 1448 /* Passkey rounds are complete - start DHKey Check */ 1449 sc_dhkey_check(smp); 1450 SMP_ALLOW_CMD(smp, SMP_CMD_DHKEY_CHECK); 1451 1452 break; 1453 1454 case SMP_CMD_PAIRING_CONFIRM: 1455 if (test_bit(SMP_FLAG_WAIT_USER, &smp->flags)) { 1456 set_bit(SMP_FLAG_CFM_PENDING, &smp->flags); 1457 return 0; 1458 } 1459 1460 SMP_ALLOW_CMD(smp, SMP_CMD_PAIRING_RANDOM); 1461 1462 if (hcon->out) { 1463 smp_send_cmd(conn, SMP_CMD_PAIRING_RANDOM, 1464 sizeof(smp->prnd), smp->prnd); 1465 return 0; 1466 } 1467 1468 return sc_passkey_send_confirm(smp); 1469 1470 case SMP_CMD_PUBLIC_KEY: 1471 default: 1472 /* Initiating device starts the round */ 1473 if (!hcon->out) 1474 return 0; 1475 1476 BT_DBG("%s Starting passkey round %u", hdev->name, 1477 smp->passkey_round + 1); 1478 1479 SMP_ALLOW_CMD(smp, SMP_CMD_PAIRING_CONFIRM); 1480 1481 return sc_passkey_send_confirm(smp); 1482 } 1483 1484 return 0; 1485 } 1486 1487 static int sc_user_reply(struct smp_chan *smp, u16 mgmt_op, __le32 passkey) 1488 { 1489 struct l2cap_conn *conn = smp->conn; 1490 struct hci_conn *hcon = conn->hcon; 1491 u8 smp_op; 1492 1493 clear_bit(SMP_FLAG_WAIT_USER, &smp->flags); 1494 1495 switch (mgmt_op) { 1496 case MGMT_OP_USER_PASSKEY_NEG_REPLY: 1497 smp_failure(smp->conn, SMP_PASSKEY_ENTRY_FAILED); 1498 return 0; 1499 case MGMT_OP_USER_CONFIRM_NEG_REPLY: 1500 smp_failure(smp->conn, SMP_NUMERIC_COMP_FAILED); 1501 return 0; 1502 case MGMT_OP_USER_PASSKEY_REPLY: 1503 hcon->passkey_notify = le32_to_cpu(passkey); 1504 smp->passkey_round = 0; 1505 1506 if (test_and_clear_bit(SMP_FLAG_CFM_PENDING, &smp->flags)) 1507 smp_op = SMP_CMD_PAIRING_CONFIRM; 1508 else 1509 smp_op = 0; 1510 1511 if (sc_passkey_round(smp, smp_op)) 1512 return -EIO; 1513 1514 return 0; 1515 } 1516 1517 /* Initiator sends DHKey check first */ 1518 if (hcon->out) { 1519 sc_dhkey_check(smp); 1520 SMP_ALLOW_CMD(smp, SMP_CMD_DHKEY_CHECK); 1521 } else if (test_and_clear_bit(SMP_FLAG_DHKEY_PENDING, &smp->flags)) { 1522 sc_dhkey_check(smp); 1523 sc_add_ltk(smp); 1524 } 1525 1526 return 0; 1527 } 1528 1529 int smp_user_confirm_reply(struct hci_conn *hcon, u16 mgmt_op, __le32 passkey) 1530 { 1531 struct l2cap_conn *conn = hcon->l2cap_data; 1532 struct l2cap_chan *chan; 1533 struct smp_chan *smp; 1534 u32 value; 1535 int err; 1536 1537 BT_DBG(""); 1538 1539 if (!conn) 1540 return -ENOTCONN; 1541 1542 chan = conn->smp; 1543 if (!chan) 1544 return -ENOTCONN; 1545 1546 l2cap_chan_lock(chan); 1547 if (!chan->data) { 1548 err = -ENOTCONN; 1549 goto unlock; 1550 } 1551 1552 smp = chan->data; 1553 1554 if (test_bit(SMP_FLAG_SC, &smp->flags)) { 1555 err = sc_user_reply(smp, mgmt_op, passkey); 1556 goto unlock; 1557 } 1558 1559 switch (mgmt_op) { 1560 case MGMT_OP_USER_PASSKEY_REPLY: 1561 value = le32_to_cpu(passkey); 1562 memset(smp->tk, 0, sizeof(smp->tk)); 1563 BT_DBG("PassKey: %d", value); 1564 put_unaligned_le32(value, smp->tk); 1565 /* Fall Through */ 1566 case MGMT_OP_USER_CONFIRM_REPLY: 1567 set_bit(SMP_FLAG_TK_VALID, &smp->flags); 1568 break; 1569 case MGMT_OP_USER_PASSKEY_NEG_REPLY: 1570 case MGMT_OP_USER_CONFIRM_NEG_REPLY: 1571 smp_failure(conn, SMP_PASSKEY_ENTRY_FAILED); 1572 err = 0; 1573 goto unlock; 1574 default: 1575 smp_failure(conn, SMP_PASSKEY_ENTRY_FAILED); 1576 err = -EOPNOTSUPP; 1577 goto unlock; 1578 } 1579 1580 err = 0; 1581 1582 /* If it is our turn to send Pairing Confirm, do so now */ 1583 if (test_bit(SMP_FLAG_CFM_PENDING, &smp->flags)) { 1584 u8 rsp = smp_confirm(smp); 1585 if (rsp) 1586 smp_failure(conn, rsp); 1587 } 1588 1589 unlock: 1590 l2cap_chan_unlock(chan); 1591 return err; 1592 } 1593 1594 static void build_bredr_pairing_cmd(struct smp_chan *smp, 1595 struct smp_cmd_pairing *req, 1596 struct smp_cmd_pairing *rsp) 1597 { 1598 struct l2cap_conn *conn = smp->conn; 1599 struct hci_dev *hdev = conn->hcon->hdev; 1600 u8 local_dist = 0, remote_dist = 0; 1601 1602 if (test_bit(HCI_BONDABLE, &hdev->dev_flags)) { 1603 local_dist = SMP_DIST_ENC_KEY | SMP_DIST_SIGN; 1604 remote_dist = SMP_DIST_ENC_KEY | SMP_DIST_SIGN; 1605 } 1606 1607 if (test_bit(HCI_RPA_RESOLVING, &hdev->dev_flags)) 1608 remote_dist |= SMP_DIST_ID_KEY; 1609 1610 if (test_bit(HCI_PRIVACY, &hdev->dev_flags)) 1611 local_dist |= SMP_DIST_ID_KEY; 1612 1613 if (!rsp) { 1614 memset(req, 0, sizeof(*req)); 1615 1616 req->init_key_dist = local_dist; 1617 req->resp_key_dist = remote_dist; 1618 req->max_key_size = SMP_MAX_ENC_KEY_SIZE; 1619 1620 smp->remote_key_dist = remote_dist; 1621 1622 return; 1623 } 1624 1625 memset(rsp, 0, sizeof(*rsp)); 1626 1627 rsp->max_key_size = SMP_MAX_ENC_KEY_SIZE; 1628 rsp->init_key_dist = req->init_key_dist & remote_dist; 1629 rsp->resp_key_dist = req->resp_key_dist & local_dist; 1630 1631 smp->remote_key_dist = rsp->init_key_dist; 1632 } 1633 1634 static u8 smp_cmd_pairing_req(struct l2cap_conn *conn, struct sk_buff *skb) 1635 { 1636 struct smp_cmd_pairing rsp, *req = (void *) skb->data; 1637 struct l2cap_chan *chan = conn->smp; 1638 struct hci_dev *hdev = conn->hcon->hdev; 1639 struct smp_chan *smp; 1640 u8 key_size, auth, sec_level; 1641 int ret; 1642 1643 BT_DBG("conn %p", conn); 1644 1645 if (skb->len < sizeof(*req)) 1646 return SMP_INVALID_PARAMS; 1647 1648 if (conn->hcon->role != HCI_ROLE_SLAVE) 1649 return SMP_CMD_NOTSUPP; 1650 1651 if (!chan->data) 1652 smp = smp_chan_create(conn); 1653 else 1654 smp = chan->data; 1655 1656 if (!smp) 1657 return SMP_UNSPECIFIED; 1658 1659 /* We didn't start the pairing, so match remote */ 1660 auth = req->auth_req & AUTH_REQ_MASK(hdev); 1661 1662 if (!test_bit(HCI_BONDABLE, &hdev->dev_flags) && 1663 (auth & SMP_AUTH_BONDING)) 1664 return SMP_PAIRING_NOTSUPP; 1665 1666 if (test_bit(HCI_SC_ONLY, &hdev->dev_flags) && !(auth & SMP_AUTH_SC)) 1667 return SMP_AUTH_REQUIREMENTS; 1668 1669 smp->preq[0] = SMP_CMD_PAIRING_REQ; 1670 memcpy(&smp->preq[1], req, sizeof(*req)); 1671 skb_pull(skb, sizeof(*req)); 1672 1673 /* SMP over BR/EDR requires special treatment */ 1674 if (conn->hcon->type == ACL_LINK) { 1675 /* We must have a BR/EDR SC link */ 1676 if (!test_bit(HCI_CONN_AES_CCM, &conn->hcon->flags) && 1677 !test_bit(HCI_FORCE_LESC, &hdev->dbg_flags)) 1678 return SMP_CROSS_TRANSP_NOT_ALLOWED; 1679 1680 set_bit(SMP_FLAG_SC, &smp->flags); 1681 1682 build_bredr_pairing_cmd(smp, req, &rsp); 1683 1684 key_size = min(req->max_key_size, rsp.max_key_size); 1685 if (check_enc_key_size(conn, key_size)) 1686 return SMP_ENC_KEY_SIZE; 1687 1688 /* Clear bits which are generated but not distributed */ 1689 smp->remote_key_dist &= ~SMP_SC_NO_DIST; 1690 1691 smp->prsp[0] = SMP_CMD_PAIRING_RSP; 1692 memcpy(&smp->prsp[1], &rsp, sizeof(rsp)); 1693 smp_send_cmd(conn, SMP_CMD_PAIRING_RSP, sizeof(rsp), &rsp); 1694 1695 smp_distribute_keys(smp); 1696 return 0; 1697 } 1698 1699 build_pairing_cmd(conn, req, &rsp, auth); 1700 1701 if (rsp.auth_req & SMP_AUTH_SC) 1702 set_bit(SMP_FLAG_SC, &smp->flags); 1703 1704 if (conn->hcon->io_capability == HCI_IO_NO_INPUT_OUTPUT) 1705 sec_level = BT_SECURITY_MEDIUM; 1706 else 1707 sec_level = authreq_to_seclevel(auth); 1708 1709 if (sec_level > conn->hcon->pending_sec_level) 1710 conn->hcon->pending_sec_level = sec_level; 1711 1712 /* If we need MITM check that it can be achieved */ 1713 if (conn->hcon->pending_sec_level >= BT_SECURITY_HIGH) { 1714 u8 method; 1715 1716 method = get_auth_method(smp, conn->hcon->io_capability, 1717 req->io_capability); 1718 if (method == JUST_WORKS || method == JUST_CFM) 1719 return SMP_AUTH_REQUIREMENTS; 1720 } 1721 1722 key_size = min(req->max_key_size, rsp.max_key_size); 1723 if (check_enc_key_size(conn, key_size)) 1724 return SMP_ENC_KEY_SIZE; 1725 1726 get_random_bytes(smp->prnd, sizeof(smp->prnd)); 1727 1728 smp->prsp[0] = SMP_CMD_PAIRING_RSP; 1729 memcpy(&smp->prsp[1], &rsp, sizeof(rsp)); 1730 1731 smp_send_cmd(conn, SMP_CMD_PAIRING_RSP, sizeof(rsp), &rsp); 1732 1733 clear_bit(SMP_FLAG_INITIATOR, &smp->flags); 1734 1735 if (test_bit(SMP_FLAG_SC, &smp->flags)) { 1736 SMP_ALLOW_CMD(smp, SMP_CMD_PUBLIC_KEY); 1737 /* Clear bits which are generated but not distributed */ 1738 smp->remote_key_dist &= ~SMP_SC_NO_DIST; 1739 /* Wait for Public Key from Initiating Device */ 1740 return 0; 1741 } else { 1742 SMP_ALLOW_CMD(smp, SMP_CMD_PAIRING_CONFIRM); 1743 } 1744 1745 /* Request setup of TK */ 1746 ret = tk_request(conn, 0, auth, rsp.io_capability, req->io_capability); 1747 if (ret) 1748 return SMP_UNSPECIFIED; 1749 1750 return 0; 1751 } 1752 1753 static u8 sc_send_public_key(struct smp_chan *smp) 1754 { 1755 struct hci_dev *hdev = smp->conn->hcon->hdev; 1756 1757 BT_DBG(""); 1758 1759 if (test_bit(HCI_USE_DEBUG_KEYS, &hdev->dev_flags)) { 1760 BT_DBG("Using debug keys"); 1761 memcpy(smp->local_pk, debug_pk, 64); 1762 memcpy(smp->local_sk, debug_sk, 32); 1763 set_bit(SMP_FLAG_DEBUG_KEY, &smp->flags); 1764 } else { 1765 while (true) { 1766 /* Generate local key pair for Secure Connections */ 1767 if (!ecc_make_key(smp->local_pk, smp->local_sk)) 1768 return SMP_UNSPECIFIED; 1769 1770 /* This is unlikely, but we need to check that 1771 * we didn't accidentially generate a debug key. 1772 */ 1773 if (memcmp(smp->local_sk, debug_sk, 32)) 1774 break; 1775 } 1776 } 1777 1778 SMP_DBG("Local Public Key X: %32phN", smp->local_pk); 1779 SMP_DBG("Local Public Key Y: %32phN", &smp->local_pk[32]); 1780 SMP_DBG("Local Private Key: %32phN", smp->local_sk); 1781 1782 smp_send_cmd(smp->conn, SMP_CMD_PUBLIC_KEY, 64, smp->local_pk); 1783 1784 return 0; 1785 } 1786 1787 static u8 smp_cmd_pairing_rsp(struct l2cap_conn *conn, struct sk_buff *skb) 1788 { 1789 struct smp_cmd_pairing *req, *rsp = (void *) skb->data; 1790 struct l2cap_chan *chan = conn->smp; 1791 struct smp_chan *smp = chan->data; 1792 struct hci_dev *hdev = conn->hcon->hdev; 1793 u8 key_size, auth; 1794 int ret; 1795 1796 BT_DBG("conn %p", conn); 1797 1798 if (skb->len < sizeof(*rsp)) 1799 return SMP_INVALID_PARAMS; 1800 1801 if (conn->hcon->role != HCI_ROLE_MASTER) 1802 return SMP_CMD_NOTSUPP; 1803 1804 skb_pull(skb, sizeof(*rsp)); 1805 1806 req = (void *) &smp->preq[1]; 1807 1808 key_size = min(req->max_key_size, rsp->max_key_size); 1809 if (check_enc_key_size(conn, key_size)) 1810 return SMP_ENC_KEY_SIZE; 1811 1812 auth = rsp->auth_req & AUTH_REQ_MASK(hdev); 1813 1814 if (test_bit(HCI_SC_ONLY, &hdev->dev_flags) && !(auth & SMP_AUTH_SC)) 1815 return SMP_AUTH_REQUIREMENTS; 1816 1817 smp->prsp[0] = SMP_CMD_PAIRING_RSP; 1818 memcpy(&smp->prsp[1], rsp, sizeof(*rsp)); 1819 1820 /* Update remote key distribution in case the remote cleared 1821 * some bits that we had enabled in our request. 1822 */ 1823 smp->remote_key_dist &= rsp->resp_key_dist; 1824 1825 /* For BR/EDR this means we're done and can start phase 3 */ 1826 if (conn->hcon->type == ACL_LINK) { 1827 /* Clear bits which are generated but not distributed */ 1828 smp->remote_key_dist &= ~SMP_SC_NO_DIST; 1829 smp_distribute_keys(smp); 1830 return 0; 1831 } 1832 1833 if ((req->auth_req & SMP_AUTH_SC) && (auth & SMP_AUTH_SC)) 1834 set_bit(SMP_FLAG_SC, &smp->flags); 1835 else if (conn->hcon->pending_sec_level > BT_SECURITY_HIGH) 1836 conn->hcon->pending_sec_level = BT_SECURITY_HIGH; 1837 1838 /* If we need MITM check that it can be achieved */ 1839 if (conn->hcon->pending_sec_level >= BT_SECURITY_HIGH) { 1840 u8 method; 1841 1842 method = get_auth_method(smp, req->io_capability, 1843 rsp->io_capability); 1844 if (method == JUST_WORKS || method == JUST_CFM) 1845 return SMP_AUTH_REQUIREMENTS; 1846 } 1847 1848 get_random_bytes(smp->prnd, sizeof(smp->prnd)); 1849 1850 /* Update remote key distribution in case the remote cleared 1851 * some bits that we had enabled in our request. 1852 */ 1853 smp->remote_key_dist &= rsp->resp_key_dist; 1854 1855 if (test_bit(SMP_FLAG_SC, &smp->flags)) { 1856 /* Clear bits which are generated but not distributed */ 1857 smp->remote_key_dist &= ~SMP_SC_NO_DIST; 1858 SMP_ALLOW_CMD(smp, SMP_CMD_PUBLIC_KEY); 1859 return sc_send_public_key(smp); 1860 } 1861 1862 auth |= req->auth_req; 1863 1864 ret = tk_request(conn, 0, auth, req->io_capability, rsp->io_capability); 1865 if (ret) 1866 return SMP_UNSPECIFIED; 1867 1868 set_bit(SMP_FLAG_CFM_PENDING, &smp->flags); 1869 1870 /* Can't compose response until we have been confirmed */ 1871 if (test_bit(SMP_FLAG_TK_VALID, &smp->flags)) 1872 return smp_confirm(smp); 1873 1874 return 0; 1875 } 1876 1877 static u8 sc_check_confirm(struct smp_chan *smp) 1878 { 1879 struct l2cap_conn *conn = smp->conn; 1880 1881 BT_DBG(""); 1882 1883 /* Public Key exchange must happen before any other steps */ 1884 if (!test_bit(SMP_FLAG_REMOTE_PK, &smp->flags)) 1885 return SMP_UNSPECIFIED; 1886 1887 if (smp->method == REQ_PASSKEY || smp->method == DSP_PASSKEY) 1888 return sc_passkey_round(smp, SMP_CMD_PAIRING_CONFIRM); 1889 1890 if (conn->hcon->out) { 1891 smp_send_cmd(conn, SMP_CMD_PAIRING_RANDOM, sizeof(smp->prnd), 1892 smp->prnd); 1893 SMP_ALLOW_CMD(smp, SMP_CMD_PAIRING_RANDOM); 1894 } 1895 1896 return 0; 1897 } 1898 1899 static u8 smp_cmd_pairing_confirm(struct l2cap_conn *conn, struct sk_buff *skb) 1900 { 1901 struct l2cap_chan *chan = conn->smp; 1902 struct smp_chan *smp = chan->data; 1903 1904 BT_DBG("conn %p %s", conn, conn->hcon->out ? "master" : "slave"); 1905 1906 if (skb->len < sizeof(smp->pcnf)) 1907 return SMP_INVALID_PARAMS; 1908 1909 memcpy(smp->pcnf, skb->data, sizeof(smp->pcnf)); 1910 skb_pull(skb, sizeof(smp->pcnf)); 1911 1912 if (test_bit(SMP_FLAG_SC, &smp->flags)) 1913 return sc_check_confirm(smp); 1914 1915 if (conn->hcon->out) { 1916 smp_send_cmd(conn, SMP_CMD_PAIRING_RANDOM, sizeof(smp->prnd), 1917 smp->prnd); 1918 SMP_ALLOW_CMD(smp, SMP_CMD_PAIRING_RANDOM); 1919 return 0; 1920 } 1921 1922 if (test_bit(SMP_FLAG_TK_VALID, &smp->flags)) 1923 return smp_confirm(smp); 1924 else 1925 set_bit(SMP_FLAG_CFM_PENDING, &smp->flags); 1926 1927 return 0; 1928 } 1929 1930 static u8 smp_cmd_pairing_random(struct l2cap_conn *conn, struct sk_buff *skb) 1931 { 1932 struct l2cap_chan *chan = conn->smp; 1933 struct smp_chan *smp = chan->data; 1934 struct hci_conn *hcon = conn->hcon; 1935 u8 *pkax, *pkbx, *na, *nb; 1936 u32 passkey; 1937 int err; 1938 1939 BT_DBG("conn %p", conn); 1940 1941 if (skb->len < sizeof(smp->rrnd)) 1942 return SMP_INVALID_PARAMS; 1943 1944 memcpy(smp->rrnd, skb->data, sizeof(smp->rrnd)); 1945 skb_pull(skb, sizeof(smp->rrnd)); 1946 1947 if (!test_bit(SMP_FLAG_SC, &smp->flags)) 1948 return smp_random(smp); 1949 1950 if (hcon->out) { 1951 pkax = smp->local_pk; 1952 pkbx = smp->remote_pk; 1953 na = smp->prnd; 1954 nb = smp->rrnd; 1955 } else { 1956 pkax = smp->remote_pk; 1957 pkbx = smp->local_pk; 1958 na = smp->rrnd; 1959 nb = smp->prnd; 1960 } 1961 1962 if (smp->method == REQ_OOB) { 1963 if (!hcon->out) 1964 smp_send_cmd(conn, SMP_CMD_PAIRING_RANDOM, 1965 sizeof(smp->prnd), smp->prnd); 1966 SMP_ALLOW_CMD(smp, SMP_CMD_DHKEY_CHECK); 1967 goto mackey_and_ltk; 1968 } 1969 1970 /* Passkey entry has special treatment */ 1971 if (smp->method == REQ_PASSKEY || smp->method == DSP_PASSKEY) 1972 return sc_passkey_round(smp, SMP_CMD_PAIRING_RANDOM); 1973 1974 if (hcon->out) { 1975 u8 cfm[16]; 1976 1977 err = smp_f4(smp->tfm_cmac, smp->remote_pk, smp->local_pk, 1978 smp->rrnd, 0, cfm); 1979 if (err) 1980 return SMP_UNSPECIFIED; 1981 1982 if (memcmp(smp->pcnf, cfm, 16)) 1983 return SMP_CONFIRM_FAILED; 1984 } else { 1985 smp_send_cmd(conn, SMP_CMD_PAIRING_RANDOM, sizeof(smp->prnd), 1986 smp->prnd); 1987 SMP_ALLOW_CMD(smp, SMP_CMD_DHKEY_CHECK); 1988 } 1989 1990 mackey_and_ltk: 1991 /* Generate MacKey and LTK */ 1992 err = sc_mackey_and_ltk(smp, smp->mackey, smp->tk); 1993 if (err) 1994 return SMP_UNSPECIFIED; 1995 1996 if (smp->method == JUST_WORKS || smp->method == REQ_OOB) { 1997 if (hcon->out) { 1998 sc_dhkey_check(smp); 1999 SMP_ALLOW_CMD(smp, SMP_CMD_DHKEY_CHECK); 2000 } 2001 return 0; 2002 } 2003 2004 err = smp_g2(smp->tfm_cmac, pkax, pkbx, na, nb, &passkey); 2005 if (err) 2006 return SMP_UNSPECIFIED; 2007 2008 err = mgmt_user_confirm_request(hcon->hdev, &hcon->dst, hcon->type, 2009 hcon->dst_type, passkey, 0); 2010 if (err) 2011 return SMP_UNSPECIFIED; 2012 2013 set_bit(SMP_FLAG_WAIT_USER, &smp->flags); 2014 2015 return 0; 2016 } 2017 2018 static bool smp_ltk_encrypt(struct l2cap_conn *conn, u8 sec_level) 2019 { 2020 struct smp_ltk *key; 2021 struct hci_conn *hcon = conn->hcon; 2022 2023 key = hci_find_ltk(hcon->hdev, &hcon->dst, hcon->dst_type, hcon->role); 2024 if (!key) 2025 return false; 2026 2027 if (smp_ltk_sec_level(key) < sec_level) 2028 return false; 2029 2030 if (test_and_set_bit(HCI_CONN_ENCRYPT_PEND, &hcon->flags)) 2031 return true; 2032 2033 hci_le_start_enc(hcon, key->ediv, key->rand, key->val); 2034 hcon->enc_key_size = key->enc_size; 2035 2036 /* We never store STKs for master role, so clear this flag */ 2037 clear_bit(HCI_CONN_STK_ENCRYPT, &hcon->flags); 2038 2039 return true; 2040 } 2041 2042 bool smp_sufficient_security(struct hci_conn *hcon, u8 sec_level, 2043 enum smp_key_pref key_pref) 2044 { 2045 if (sec_level == BT_SECURITY_LOW) 2046 return true; 2047 2048 /* If we're encrypted with an STK but the caller prefers using 2049 * LTK claim insufficient security. This way we allow the 2050 * connection to be re-encrypted with an LTK, even if the LTK 2051 * provides the same level of security. Only exception is if we 2052 * don't have an LTK (e.g. because of key distribution bits). 2053 */ 2054 if (key_pref == SMP_USE_LTK && 2055 test_bit(HCI_CONN_STK_ENCRYPT, &hcon->flags) && 2056 hci_find_ltk(hcon->hdev, &hcon->dst, hcon->dst_type, hcon->role)) 2057 return false; 2058 2059 if (hcon->sec_level >= sec_level) 2060 return true; 2061 2062 return false; 2063 } 2064 2065 static u8 smp_cmd_security_req(struct l2cap_conn *conn, struct sk_buff *skb) 2066 { 2067 struct smp_cmd_security_req *rp = (void *) skb->data; 2068 struct smp_cmd_pairing cp; 2069 struct hci_conn *hcon = conn->hcon; 2070 struct hci_dev *hdev = hcon->hdev; 2071 struct smp_chan *smp; 2072 u8 sec_level, auth; 2073 2074 BT_DBG("conn %p", conn); 2075 2076 if (skb->len < sizeof(*rp)) 2077 return SMP_INVALID_PARAMS; 2078 2079 if (hcon->role != HCI_ROLE_MASTER) 2080 return SMP_CMD_NOTSUPP; 2081 2082 auth = rp->auth_req & AUTH_REQ_MASK(hdev); 2083 2084 if (test_bit(HCI_SC_ONLY, &hdev->dev_flags) && !(auth & SMP_AUTH_SC)) 2085 return SMP_AUTH_REQUIREMENTS; 2086 2087 if (hcon->io_capability == HCI_IO_NO_INPUT_OUTPUT) 2088 sec_level = BT_SECURITY_MEDIUM; 2089 else 2090 sec_level = authreq_to_seclevel(auth); 2091 2092 if (smp_sufficient_security(hcon, sec_level, SMP_USE_LTK)) 2093 return 0; 2094 2095 if (sec_level > hcon->pending_sec_level) 2096 hcon->pending_sec_level = sec_level; 2097 2098 if (smp_ltk_encrypt(conn, hcon->pending_sec_level)) 2099 return 0; 2100 2101 smp = smp_chan_create(conn); 2102 if (!smp) 2103 return SMP_UNSPECIFIED; 2104 2105 if (!test_bit(HCI_BONDABLE, &hcon->hdev->dev_flags) && 2106 (auth & SMP_AUTH_BONDING)) 2107 return SMP_PAIRING_NOTSUPP; 2108 2109 skb_pull(skb, sizeof(*rp)); 2110 2111 memset(&cp, 0, sizeof(cp)); 2112 build_pairing_cmd(conn, &cp, NULL, auth); 2113 2114 smp->preq[0] = SMP_CMD_PAIRING_REQ; 2115 memcpy(&smp->preq[1], &cp, sizeof(cp)); 2116 2117 smp_send_cmd(conn, SMP_CMD_PAIRING_REQ, sizeof(cp), &cp); 2118 SMP_ALLOW_CMD(smp, SMP_CMD_PAIRING_RSP); 2119 2120 return 0; 2121 } 2122 2123 int smp_conn_security(struct hci_conn *hcon, __u8 sec_level) 2124 { 2125 struct l2cap_conn *conn = hcon->l2cap_data; 2126 struct l2cap_chan *chan; 2127 struct smp_chan *smp; 2128 __u8 authreq; 2129 int ret; 2130 2131 BT_DBG("conn %p hcon %p level 0x%2.2x", conn, hcon, sec_level); 2132 2133 /* This may be NULL if there's an unexpected disconnection */ 2134 if (!conn) 2135 return 1; 2136 2137 chan = conn->smp; 2138 2139 if (!test_bit(HCI_LE_ENABLED, &hcon->hdev->dev_flags)) 2140 return 1; 2141 2142 if (smp_sufficient_security(hcon, sec_level, SMP_USE_LTK)) 2143 return 1; 2144 2145 if (sec_level > hcon->pending_sec_level) 2146 hcon->pending_sec_level = sec_level; 2147 2148 if (hcon->role == HCI_ROLE_MASTER) 2149 if (smp_ltk_encrypt(conn, hcon->pending_sec_level)) 2150 return 0; 2151 2152 l2cap_chan_lock(chan); 2153 2154 /* If SMP is already in progress ignore this request */ 2155 if (chan->data) { 2156 ret = 0; 2157 goto unlock; 2158 } 2159 2160 smp = smp_chan_create(conn); 2161 if (!smp) { 2162 ret = 1; 2163 goto unlock; 2164 } 2165 2166 authreq = seclevel_to_authreq(sec_level); 2167 2168 if (test_bit(HCI_SC_ENABLED, &hcon->hdev->dev_flags)) 2169 authreq |= SMP_AUTH_SC; 2170 2171 /* Require MITM if IO Capability allows or the security level 2172 * requires it. 2173 */ 2174 if (hcon->io_capability != HCI_IO_NO_INPUT_OUTPUT || 2175 hcon->pending_sec_level > BT_SECURITY_MEDIUM) 2176 authreq |= SMP_AUTH_MITM; 2177 2178 if (hcon->role == HCI_ROLE_MASTER) { 2179 struct smp_cmd_pairing cp; 2180 2181 build_pairing_cmd(conn, &cp, NULL, authreq); 2182 smp->preq[0] = SMP_CMD_PAIRING_REQ; 2183 memcpy(&smp->preq[1], &cp, sizeof(cp)); 2184 2185 smp_send_cmd(conn, SMP_CMD_PAIRING_REQ, sizeof(cp), &cp); 2186 SMP_ALLOW_CMD(smp, SMP_CMD_PAIRING_RSP); 2187 } else { 2188 struct smp_cmd_security_req cp; 2189 cp.auth_req = authreq; 2190 smp_send_cmd(conn, SMP_CMD_SECURITY_REQ, sizeof(cp), &cp); 2191 SMP_ALLOW_CMD(smp, SMP_CMD_PAIRING_REQ); 2192 } 2193 2194 set_bit(SMP_FLAG_INITIATOR, &smp->flags); 2195 ret = 0; 2196 2197 unlock: 2198 l2cap_chan_unlock(chan); 2199 return ret; 2200 } 2201 2202 static int smp_cmd_encrypt_info(struct l2cap_conn *conn, struct sk_buff *skb) 2203 { 2204 struct smp_cmd_encrypt_info *rp = (void *) skb->data; 2205 struct l2cap_chan *chan = conn->smp; 2206 struct smp_chan *smp = chan->data; 2207 2208 BT_DBG("conn %p", conn); 2209 2210 if (skb->len < sizeof(*rp)) 2211 return SMP_INVALID_PARAMS; 2212 2213 SMP_ALLOW_CMD(smp, SMP_CMD_MASTER_IDENT); 2214 2215 skb_pull(skb, sizeof(*rp)); 2216 2217 memcpy(smp->tk, rp->ltk, sizeof(smp->tk)); 2218 2219 return 0; 2220 } 2221 2222 static int smp_cmd_master_ident(struct l2cap_conn *conn, struct sk_buff *skb) 2223 { 2224 struct smp_cmd_master_ident *rp = (void *) skb->data; 2225 struct l2cap_chan *chan = conn->smp; 2226 struct smp_chan *smp = chan->data; 2227 struct hci_dev *hdev = conn->hcon->hdev; 2228 struct hci_conn *hcon = conn->hcon; 2229 struct smp_ltk *ltk; 2230 u8 authenticated; 2231 2232 BT_DBG("conn %p", conn); 2233 2234 if (skb->len < sizeof(*rp)) 2235 return SMP_INVALID_PARAMS; 2236 2237 /* Mark the information as received */ 2238 smp->remote_key_dist &= ~SMP_DIST_ENC_KEY; 2239 2240 if (smp->remote_key_dist & SMP_DIST_ID_KEY) 2241 SMP_ALLOW_CMD(smp, SMP_CMD_IDENT_INFO); 2242 else if (smp->remote_key_dist & SMP_DIST_SIGN) 2243 SMP_ALLOW_CMD(smp, SMP_CMD_SIGN_INFO); 2244 2245 skb_pull(skb, sizeof(*rp)); 2246 2247 authenticated = (hcon->sec_level == BT_SECURITY_HIGH); 2248 ltk = hci_add_ltk(hdev, &hcon->dst, hcon->dst_type, SMP_LTK, 2249 authenticated, smp->tk, smp->enc_key_size, 2250 rp->ediv, rp->rand); 2251 smp->ltk = ltk; 2252 if (!(smp->remote_key_dist & KEY_DIST_MASK)) 2253 smp_distribute_keys(smp); 2254 2255 return 0; 2256 } 2257 2258 static int smp_cmd_ident_info(struct l2cap_conn *conn, struct sk_buff *skb) 2259 { 2260 struct smp_cmd_ident_info *info = (void *) skb->data; 2261 struct l2cap_chan *chan = conn->smp; 2262 struct smp_chan *smp = chan->data; 2263 2264 BT_DBG(""); 2265 2266 if (skb->len < sizeof(*info)) 2267 return SMP_INVALID_PARAMS; 2268 2269 SMP_ALLOW_CMD(smp, SMP_CMD_IDENT_ADDR_INFO); 2270 2271 skb_pull(skb, sizeof(*info)); 2272 2273 memcpy(smp->irk, info->irk, 16); 2274 2275 return 0; 2276 } 2277 2278 static int smp_cmd_ident_addr_info(struct l2cap_conn *conn, 2279 struct sk_buff *skb) 2280 { 2281 struct smp_cmd_ident_addr_info *info = (void *) skb->data; 2282 struct l2cap_chan *chan = conn->smp; 2283 struct smp_chan *smp = chan->data; 2284 struct hci_conn *hcon = conn->hcon; 2285 bdaddr_t rpa; 2286 2287 BT_DBG(""); 2288 2289 if (skb->len < sizeof(*info)) 2290 return SMP_INVALID_PARAMS; 2291 2292 /* Mark the information as received */ 2293 smp->remote_key_dist &= ~SMP_DIST_ID_KEY; 2294 2295 if (smp->remote_key_dist & SMP_DIST_SIGN) 2296 SMP_ALLOW_CMD(smp, SMP_CMD_SIGN_INFO); 2297 2298 skb_pull(skb, sizeof(*info)); 2299 2300 /* Strictly speaking the Core Specification (4.1) allows sending 2301 * an empty address which would force us to rely on just the IRK 2302 * as "identity information". However, since such 2303 * implementations are not known of and in order to not over 2304 * complicate our implementation, simply pretend that we never 2305 * received an IRK for such a device. 2306 */ 2307 if (!bacmp(&info->bdaddr, BDADDR_ANY)) { 2308 BT_ERR("Ignoring IRK with no identity address"); 2309 goto distribute; 2310 } 2311 2312 bacpy(&smp->id_addr, &info->bdaddr); 2313 smp->id_addr_type = info->addr_type; 2314 2315 if (hci_bdaddr_is_rpa(&hcon->dst, hcon->dst_type)) 2316 bacpy(&rpa, &hcon->dst); 2317 else 2318 bacpy(&rpa, BDADDR_ANY); 2319 2320 smp->remote_irk = hci_add_irk(conn->hcon->hdev, &smp->id_addr, 2321 smp->id_addr_type, smp->irk, &rpa); 2322 2323 distribute: 2324 if (!(smp->remote_key_dist & KEY_DIST_MASK)) 2325 smp_distribute_keys(smp); 2326 2327 return 0; 2328 } 2329 2330 static int smp_cmd_sign_info(struct l2cap_conn *conn, struct sk_buff *skb) 2331 { 2332 struct smp_cmd_sign_info *rp = (void *) skb->data; 2333 struct l2cap_chan *chan = conn->smp; 2334 struct smp_chan *smp = chan->data; 2335 struct smp_csrk *csrk; 2336 2337 BT_DBG("conn %p", conn); 2338 2339 if (skb->len < sizeof(*rp)) 2340 return SMP_INVALID_PARAMS; 2341 2342 /* Mark the information as received */ 2343 smp->remote_key_dist &= ~SMP_DIST_SIGN; 2344 2345 skb_pull(skb, sizeof(*rp)); 2346 2347 csrk = kzalloc(sizeof(*csrk), GFP_KERNEL); 2348 if (csrk) { 2349 csrk->master = 0x01; 2350 memcpy(csrk->val, rp->csrk, sizeof(csrk->val)); 2351 } 2352 smp->csrk = csrk; 2353 smp_distribute_keys(smp); 2354 2355 return 0; 2356 } 2357 2358 static u8 sc_select_method(struct smp_chan *smp) 2359 { 2360 struct l2cap_conn *conn = smp->conn; 2361 struct hci_conn *hcon = conn->hcon; 2362 struct smp_cmd_pairing *local, *remote; 2363 u8 local_mitm, remote_mitm, local_io, remote_io, method; 2364 2365 if (test_bit(SMP_FLAG_OOB, &smp->flags)) 2366 return REQ_OOB; 2367 2368 /* The preq/prsp contain the raw Pairing Request/Response PDUs 2369 * which are needed as inputs to some crypto functions. To get 2370 * the "struct smp_cmd_pairing" from them we need to skip the 2371 * first byte which contains the opcode. 2372 */ 2373 if (hcon->out) { 2374 local = (void *) &smp->preq[1]; 2375 remote = (void *) &smp->prsp[1]; 2376 } else { 2377 local = (void *) &smp->prsp[1]; 2378 remote = (void *) &smp->preq[1]; 2379 } 2380 2381 local_io = local->io_capability; 2382 remote_io = remote->io_capability; 2383 2384 local_mitm = (local->auth_req & SMP_AUTH_MITM); 2385 remote_mitm = (remote->auth_req & SMP_AUTH_MITM); 2386 2387 /* If either side wants MITM, look up the method from the table, 2388 * otherwise use JUST WORKS. 2389 */ 2390 if (local_mitm || remote_mitm) 2391 method = get_auth_method(smp, local_io, remote_io); 2392 else 2393 method = JUST_WORKS; 2394 2395 /* Don't confirm locally initiated pairing attempts */ 2396 if (method == JUST_CFM && test_bit(SMP_FLAG_INITIATOR, &smp->flags)) 2397 method = JUST_WORKS; 2398 2399 return method; 2400 } 2401 2402 static int smp_cmd_public_key(struct l2cap_conn *conn, struct sk_buff *skb) 2403 { 2404 struct smp_cmd_public_key *key = (void *) skb->data; 2405 struct hci_conn *hcon = conn->hcon; 2406 struct l2cap_chan *chan = conn->smp; 2407 struct smp_chan *smp = chan->data; 2408 struct hci_dev *hdev = hcon->hdev; 2409 struct smp_cmd_pairing_confirm cfm; 2410 int err; 2411 2412 BT_DBG("conn %p", conn); 2413 2414 if (skb->len < sizeof(*key)) 2415 return SMP_INVALID_PARAMS; 2416 2417 memcpy(smp->remote_pk, key, 64); 2418 2419 /* Non-initiating device sends its public key after receiving 2420 * the key from the initiating device. 2421 */ 2422 if (!hcon->out) { 2423 err = sc_send_public_key(smp); 2424 if (err) 2425 return err; 2426 } 2427 2428 SMP_DBG("Remote Public Key X: %32phN", smp->remote_pk); 2429 SMP_DBG("Remote Public Key Y: %32phN", &smp->remote_pk[32]); 2430 2431 if (!ecdh_shared_secret(smp->remote_pk, smp->local_sk, smp->dhkey)) 2432 return SMP_UNSPECIFIED; 2433 2434 SMP_DBG("DHKey %32phN", smp->dhkey); 2435 2436 set_bit(SMP_FLAG_REMOTE_PK, &smp->flags); 2437 2438 smp->method = sc_select_method(smp); 2439 2440 BT_DBG("%s selected method 0x%02x", hdev->name, smp->method); 2441 2442 /* JUST_WORKS and JUST_CFM result in an unauthenticated key */ 2443 if (smp->method == JUST_WORKS || smp->method == JUST_CFM) 2444 hcon->pending_sec_level = BT_SECURITY_MEDIUM; 2445 else 2446 hcon->pending_sec_level = BT_SECURITY_FIPS; 2447 2448 if (!memcmp(debug_pk, smp->remote_pk, 64)) 2449 set_bit(SMP_FLAG_DEBUG_KEY, &smp->flags); 2450 2451 if (smp->method == DSP_PASSKEY) { 2452 get_random_bytes(&hcon->passkey_notify, 2453 sizeof(hcon->passkey_notify)); 2454 hcon->passkey_notify %= 1000000; 2455 hcon->passkey_entered = 0; 2456 smp->passkey_round = 0; 2457 if (mgmt_user_passkey_notify(hdev, &hcon->dst, hcon->type, 2458 hcon->dst_type, 2459 hcon->passkey_notify, 2460 hcon->passkey_entered)) 2461 return SMP_UNSPECIFIED; 2462 SMP_ALLOW_CMD(smp, SMP_CMD_PAIRING_CONFIRM); 2463 return sc_passkey_round(smp, SMP_CMD_PUBLIC_KEY); 2464 } 2465 2466 if (smp->method == REQ_OOB) { 2467 err = smp_f4(smp->tfm_cmac, smp->remote_pk, smp->remote_pk, 2468 smp->rr, 0, cfm.confirm_val); 2469 if (err) 2470 return SMP_UNSPECIFIED; 2471 2472 if (memcmp(cfm.confirm_val, smp->pcnf, 16)) 2473 return SMP_CONFIRM_FAILED; 2474 2475 if (hcon->out) 2476 smp_send_cmd(conn, SMP_CMD_PAIRING_RANDOM, 2477 sizeof(smp->prnd), smp->prnd); 2478 2479 SMP_ALLOW_CMD(smp, SMP_CMD_PAIRING_RANDOM); 2480 2481 return 0; 2482 } 2483 2484 if (hcon->out) 2485 SMP_ALLOW_CMD(smp, SMP_CMD_PAIRING_CONFIRM); 2486 2487 if (smp->method == REQ_PASSKEY) { 2488 if (mgmt_user_passkey_request(hdev, &hcon->dst, hcon->type, 2489 hcon->dst_type)) 2490 return SMP_UNSPECIFIED; 2491 SMP_ALLOW_CMD(smp, SMP_CMD_PAIRING_CONFIRM); 2492 set_bit(SMP_FLAG_WAIT_USER, &smp->flags); 2493 return 0; 2494 } 2495 2496 /* The Initiating device waits for the non-initiating device to 2497 * send the confirm value. 2498 */ 2499 if (conn->hcon->out) 2500 return 0; 2501 2502 err = smp_f4(smp->tfm_cmac, smp->local_pk, smp->remote_pk, smp->prnd, 2503 0, cfm.confirm_val); 2504 if (err) 2505 return SMP_UNSPECIFIED; 2506 2507 smp_send_cmd(conn, SMP_CMD_PAIRING_CONFIRM, sizeof(cfm), &cfm); 2508 SMP_ALLOW_CMD(smp, SMP_CMD_PAIRING_RANDOM); 2509 2510 return 0; 2511 } 2512 2513 static int smp_cmd_dhkey_check(struct l2cap_conn *conn, struct sk_buff *skb) 2514 { 2515 struct smp_cmd_dhkey_check *check = (void *) skb->data; 2516 struct l2cap_chan *chan = conn->smp; 2517 struct hci_conn *hcon = conn->hcon; 2518 struct smp_chan *smp = chan->data; 2519 u8 a[7], b[7], *local_addr, *remote_addr; 2520 u8 io_cap[3], r[16], e[16]; 2521 int err; 2522 2523 BT_DBG("conn %p", conn); 2524 2525 if (skb->len < sizeof(*check)) 2526 return SMP_INVALID_PARAMS; 2527 2528 memcpy(a, &hcon->init_addr, 6); 2529 memcpy(b, &hcon->resp_addr, 6); 2530 a[6] = hcon->init_addr_type; 2531 b[6] = hcon->resp_addr_type; 2532 2533 if (hcon->out) { 2534 local_addr = a; 2535 remote_addr = b; 2536 memcpy(io_cap, &smp->prsp[1], 3); 2537 } else { 2538 local_addr = b; 2539 remote_addr = a; 2540 memcpy(io_cap, &smp->preq[1], 3); 2541 } 2542 2543 memset(r, 0, sizeof(r)); 2544 2545 if (smp->method == REQ_PASSKEY || smp->method == DSP_PASSKEY) 2546 put_unaligned_le32(hcon->passkey_notify, r); 2547 2548 err = smp_f6(smp->tfm_cmac, smp->mackey, smp->rrnd, smp->prnd, r, 2549 io_cap, remote_addr, local_addr, e); 2550 if (err) 2551 return SMP_UNSPECIFIED; 2552 2553 if (memcmp(check->e, e, 16)) 2554 return SMP_DHKEY_CHECK_FAILED; 2555 2556 if (!hcon->out) { 2557 if (test_bit(SMP_FLAG_WAIT_USER, &smp->flags)) { 2558 set_bit(SMP_FLAG_DHKEY_PENDING, &smp->flags); 2559 return 0; 2560 } 2561 2562 /* Slave sends DHKey check as response to master */ 2563 sc_dhkey_check(smp); 2564 } 2565 2566 sc_add_ltk(smp); 2567 2568 if (hcon->out) { 2569 hci_le_start_enc(hcon, 0, 0, smp->tk); 2570 hcon->enc_key_size = smp->enc_key_size; 2571 } 2572 2573 return 0; 2574 } 2575 2576 static int smp_cmd_keypress_notify(struct l2cap_conn *conn, 2577 struct sk_buff *skb) 2578 { 2579 struct smp_cmd_keypress_notify *kp = (void *) skb->data; 2580 2581 BT_DBG("value 0x%02x", kp->value); 2582 2583 return 0; 2584 } 2585 2586 static int smp_sig_channel(struct l2cap_chan *chan, struct sk_buff *skb) 2587 { 2588 struct l2cap_conn *conn = chan->conn; 2589 struct hci_conn *hcon = conn->hcon; 2590 struct smp_chan *smp; 2591 __u8 code, reason; 2592 int err = 0; 2593 2594 if (skb->len < 1) 2595 return -EILSEQ; 2596 2597 if (!test_bit(HCI_LE_ENABLED, &hcon->hdev->dev_flags)) { 2598 reason = SMP_PAIRING_NOTSUPP; 2599 goto done; 2600 } 2601 2602 code = skb->data[0]; 2603 skb_pull(skb, sizeof(code)); 2604 2605 smp = chan->data; 2606 2607 if (code > SMP_CMD_MAX) 2608 goto drop; 2609 2610 if (smp && !test_and_clear_bit(code, &smp->allow_cmd)) 2611 goto drop; 2612 2613 /* If we don't have a context the only allowed commands are 2614 * pairing request and security request. 2615 */ 2616 if (!smp && code != SMP_CMD_PAIRING_REQ && code != SMP_CMD_SECURITY_REQ) 2617 goto drop; 2618 2619 switch (code) { 2620 case SMP_CMD_PAIRING_REQ: 2621 reason = smp_cmd_pairing_req(conn, skb); 2622 break; 2623 2624 case SMP_CMD_PAIRING_FAIL: 2625 smp_failure(conn, 0); 2626 err = -EPERM; 2627 break; 2628 2629 case SMP_CMD_PAIRING_RSP: 2630 reason = smp_cmd_pairing_rsp(conn, skb); 2631 break; 2632 2633 case SMP_CMD_SECURITY_REQ: 2634 reason = smp_cmd_security_req(conn, skb); 2635 break; 2636 2637 case SMP_CMD_PAIRING_CONFIRM: 2638 reason = smp_cmd_pairing_confirm(conn, skb); 2639 break; 2640 2641 case SMP_CMD_PAIRING_RANDOM: 2642 reason = smp_cmd_pairing_random(conn, skb); 2643 break; 2644 2645 case SMP_CMD_ENCRYPT_INFO: 2646 reason = smp_cmd_encrypt_info(conn, skb); 2647 break; 2648 2649 case SMP_CMD_MASTER_IDENT: 2650 reason = smp_cmd_master_ident(conn, skb); 2651 break; 2652 2653 case SMP_CMD_IDENT_INFO: 2654 reason = smp_cmd_ident_info(conn, skb); 2655 break; 2656 2657 case SMP_CMD_IDENT_ADDR_INFO: 2658 reason = smp_cmd_ident_addr_info(conn, skb); 2659 break; 2660 2661 case SMP_CMD_SIGN_INFO: 2662 reason = smp_cmd_sign_info(conn, skb); 2663 break; 2664 2665 case SMP_CMD_PUBLIC_KEY: 2666 reason = smp_cmd_public_key(conn, skb); 2667 break; 2668 2669 case SMP_CMD_DHKEY_CHECK: 2670 reason = smp_cmd_dhkey_check(conn, skb); 2671 break; 2672 2673 case SMP_CMD_KEYPRESS_NOTIFY: 2674 reason = smp_cmd_keypress_notify(conn, skb); 2675 break; 2676 2677 default: 2678 BT_DBG("Unknown command code 0x%2.2x", code); 2679 reason = SMP_CMD_NOTSUPP; 2680 goto done; 2681 } 2682 2683 done: 2684 if (!err) { 2685 if (reason) 2686 smp_failure(conn, reason); 2687 kfree_skb(skb); 2688 } 2689 2690 return err; 2691 2692 drop: 2693 BT_ERR("%s unexpected SMP command 0x%02x from %pMR", hcon->hdev->name, 2694 code, &hcon->dst); 2695 kfree_skb(skb); 2696 return 0; 2697 } 2698 2699 static void smp_teardown_cb(struct l2cap_chan *chan, int err) 2700 { 2701 struct l2cap_conn *conn = chan->conn; 2702 2703 BT_DBG("chan %p", chan); 2704 2705 if (chan->data) 2706 smp_chan_destroy(conn); 2707 2708 conn->smp = NULL; 2709 l2cap_chan_put(chan); 2710 } 2711 2712 static void bredr_pairing(struct l2cap_chan *chan) 2713 { 2714 struct l2cap_conn *conn = chan->conn; 2715 struct hci_conn *hcon = conn->hcon; 2716 struct hci_dev *hdev = hcon->hdev; 2717 struct smp_cmd_pairing req; 2718 struct smp_chan *smp; 2719 2720 BT_DBG("chan %p", chan); 2721 2722 /* Only new pairings are interesting */ 2723 if (!test_bit(HCI_CONN_NEW_LINK_KEY, &hcon->flags)) 2724 return; 2725 2726 /* Don't bother if we're not encrypted */ 2727 if (!test_bit(HCI_CONN_ENCRYPT, &hcon->flags)) 2728 return; 2729 2730 /* Only master may initiate SMP over BR/EDR */ 2731 if (hcon->role != HCI_ROLE_MASTER) 2732 return; 2733 2734 /* Secure Connections support must be enabled */ 2735 if (!test_bit(HCI_SC_ENABLED, &hdev->dev_flags)) 2736 return; 2737 2738 /* BR/EDR must use Secure Connections for SMP */ 2739 if (!test_bit(HCI_CONN_AES_CCM, &hcon->flags) && 2740 !test_bit(HCI_FORCE_LESC, &hdev->dbg_flags)) 2741 return; 2742 2743 /* If our LE support is not enabled don't do anything */ 2744 if (!test_bit(HCI_LE_ENABLED, &hdev->dev_flags)) 2745 return; 2746 2747 /* Don't bother if remote LE support is not enabled */ 2748 if (!lmp_host_le_capable(hcon)) 2749 return; 2750 2751 /* Remote must support SMP fixed chan for BR/EDR */ 2752 if (!(conn->remote_fixed_chan & L2CAP_FC_SMP_BREDR)) 2753 return; 2754 2755 /* Don't bother if SMP is already ongoing */ 2756 if (chan->data) 2757 return; 2758 2759 smp = smp_chan_create(conn); 2760 if (!smp) { 2761 BT_ERR("%s unable to create SMP context for BR/EDR", 2762 hdev->name); 2763 return; 2764 } 2765 2766 set_bit(SMP_FLAG_SC, &smp->flags); 2767 2768 BT_DBG("%s starting SMP over BR/EDR", hdev->name); 2769 2770 /* Prepare and send the BR/EDR SMP Pairing Request */ 2771 build_bredr_pairing_cmd(smp, &req, NULL); 2772 2773 smp->preq[0] = SMP_CMD_PAIRING_REQ; 2774 memcpy(&smp->preq[1], &req, sizeof(req)); 2775 2776 smp_send_cmd(conn, SMP_CMD_PAIRING_REQ, sizeof(req), &req); 2777 SMP_ALLOW_CMD(smp, SMP_CMD_PAIRING_RSP); 2778 } 2779 2780 static void smp_resume_cb(struct l2cap_chan *chan) 2781 { 2782 struct smp_chan *smp = chan->data; 2783 struct l2cap_conn *conn = chan->conn; 2784 struct hci_conn *hcon = conn->hcon; 2785 2786 BT_DBG("chan %p", chan); 2787 2788 if (hcon->type == ACL_LINK) { 2789 bredr_pairing(chan); 2790 return; 2791 } 2792 2793 if (!smp) 2794 return; 2795 2796 if (!test_bit(HCI_CONN_ENCRYPT, &hcon->flags)) 2797 return; 2798 2799 cancel_delayed_work(&smp->security_timer); 2800 2801 smp_distribute_keys(smp); 2802 } 2803 2804 static void smp_ready_cb(struct l2cap_chan *chan) 2805 { 2806 struct l2cap_conn *conn = chan->conn; 2807 struct hci_conn *hcon = conn->hcon; 2808 2809 BT_DBG("chan %p", chan); 2810 2811 conn->smp = chan; 2812 l2cap_chan_hold(chan); 2813 2814 if (hcon->type == ACL_LINK && test_bit(HCI_CONN_ENCRYPT, &hcon->flags)) 2815 bredr_pairing(chan); 2816 } 2817 2818 static int smp_recv_cb(struct l2cap_chan *chan, struct sk_buff *skb) 2819 { 2820 int err; 2821 2822 BT_DBG("chan %p", chan); 2823 2824 err = smp_sig_channel(chan, skb); 2825 if (err) { 2826 struct smp_chan *smp = chan->data; 2827 2828 if (smp) 2829 cancel_delayed_work_sync(&smp->security_timer); 2830 2831 hci_disconnect(chan->conn->hcon, HCI_ERROR_AUTH_FAILURE); 2832 } 2833 2834 return err; 2835 } 2836 2837 static struct sk_buff *smp_alloc_skb_cb(struct l2cap_chan *chan, 2838 unsigned long hdr_len, 2839 unsigned long len, int nb) 2840 { 2841 struct sk_buff *skb; 2842 2843 skb = bt_skb_alloc(hdr_len + len, GFP_KERNEL); 2844 if (!skb) 2845 return ERR_PTR(-ENOMEM); 2846 2847 skb->priority = HCI_PRIO_MAX; 2848 bt_cb(skb)->chan = chan; 2849 2850 return skb; 2851 } 2852 2853 static const struct l2cap_ops smp_chan_ops = { 2854 .name = "Security Manager", 2855 .ready = smp_ready_cb, 2856 .recv = smp_recv_cb, 2857 .alloc_skb = smp_alloc_skb_cb, 2858 .teardown = smp_teardown_cb, 2859 .resume = smp_resume_cb, 2860 2861 .new_connection = l2cap_chan_no_new_connection, 2862 .state_change = l2cap_chan_no_state_change, 2863 .close = l2cap_chan_no_close, 2864 .defer = l2cap_chan_no_defer, 2865 .suspend = l2cap_chan_no_suspend, 2866 .set_shutdown = l2cap_chan_no_set_shutdown, 2867 .get_sndtimeo = l2cap_chan_no_get_sndtimeo, 2868 }; 2869 2870 static inline struct l2cap_chan *smp_new_conn_cb(struct l2cap_chan *pchan) 2871 { 2872 struct l2cap_chan *chan; 2873 2874 BT_DBG("pchan %p", pchan); 2875 2876 chan = l2cap_chan_create(); 2877 if (!chan) 2878 return NULL; 2879 2880 chan->chan_type = pchan->chan_type; 2881 chan->ops = &smp_chan_ops; 2882 chan->scid = pchan->scid; 2883 chan->dcid = chan->scid; 2884 chan->imtu = pchan->imtu; 2885 chan->omtu = pchan->omtu; 2886 chan->mode = pchan->mode; 2887 2888 /* Other L2CAP channels may request SMP routines in order to 2889 * change the security level. This means that the SMP channel 2890 * lock must be considered in its own category to avoid lockdep 2891 * warnings. 2892 */ 2893 atomic_set(&chan->nesting, L2CAP_NESTING_SMP); 2894 2895 BT_DBG("created chan %p", chan); 2896 2897 return chan; 2898 } 2899 2900 static const struct l2cap_ops smp_root_chan_ops = { 2901 .name = "Security Manager Root", 2902 .new_connection = smp_new_conn_cb, 2903 2904 /* None of these are implemented for the root channel */ 2905 .close = l2cap_chan_no_close, 2906 .alloc_skb = l2cap_chan_no_alloc_skb, 2907 .recv = l2cap_chan_no_recv, 2908 .state_change = l2cap_chan_no_state_change, 2909 .teardown = l2cap_chan_no_teardown, 2910 .ready = l2cap_chan_no_ready, 2911 .defer = l2cap_chan_no_defer, 2912 .suspend = l2cap_chan_no_suspend, 2913 .resume = l2cap_chan_no_resume, 2914 .set_shutdown = l2cap_chan_no_set_shutdown, 2915 .get_sndtimeo = l2cap_chan_no_get_sndtimeo, 2916 }; 2917 2918 static struct l2cap_chan *smp_add_cid(struct hci_dev *hdev, u16 cid) 2919 { 2920 struct l2cap_chan *chan; 2921 struct crypto_blkcipher *tfm_aes; 2922 2923 if (cid == L2CAP_CID_SMP_BREDR) { 2924 tfm_aes = NULL; 2925 goto create_chan; 2926 } 2927 2928 tfm_aes = crypto_alloc_blkcipher("ecb(aes)", 0, 0); 2929 if (IS_ERR(tfm_aes)) { 2930 BT_ERR("Unable to create crypto context"); 2931 return ERR_CAST(tfm_aes); 2932 } 2933 2934 create_chan: 2935 chan = l2cap_chan_create(); 2936 if (!chan) { 2937 crypto_free_blkcipher(tfm_aes); 2938 return ERR_PTR(-ENOMEM); 2939 } 2940 2941 chan->data = tfm_aes; 2942 2943 l2cap_add_scid(chan, cid); 2944 2945 l2cap_chan_set_defaults(chan); 2946 2947 bacpy(&chan->src, &hdev->bdaddr); 2948 if (cid == L2CAP_CID_SMP) 2949 chan->src_type = BDADDR_LE_PUBLIC; 2950 else 2951 chan->src_type = BDADDR_BREDR; 2952 chan->state = BT_LISTEN; 2953 chan->mode = L2CAP_MODE_BASIC; 2954 chan->imtu = L2CAP_DEFAULT_MTU; 2955 chan->ops = &smp_root_chan_ops; 2956 2957 /* Set correct nesting level for a parent/listening channel */ 2958 atomic_set(&chan->nesting, L2CAP_NESTING_PARENT); 2959 2960 return chan; 2961 } 2962 2963 static void smp_del_chan(struct l2cap_chan *chan) 2964 { 2965 struct crypto_blkcipher *tfm_aes; 2966 2967 BT_DBG("chan %p", chan); 2968 2969 tfm_aes = chan->data; 2970 if (tfm_aes) { 2971 chan->data = NULL; 2972 crypto_free_blkcipher(tfm_aes); 2973 } 2974 2975 l2cap_chan_put(chan); 2976 } 2977 2978 int smp_register(struct hci_dev *hdev) 2979 { 2980 struct l2cap_chan *chan; 2981 2982 BT_DBG("%s", hdev->name); 2983 2984 chan = smp_add_cid(hdev, L2CAP_CID_SMP); 2985 if (IS_ERR(chan)) 2986 return PTR_ERR(chan); 2987 2988 hdev->smp_data = chan; 2989 2990 if (!lmp_sc_capable(hdev) && 2991 !test_bit(HCI_FORCE_LESC, &hdev->dbg_flags)) 2992 return 0; 2993 2994 chan = smp_add_cid(hdev, L2CAP_CID_SMP_BREDR); 2995 if (IS_ERR(chan)) { 2996 int err = PTR_ERR(chan); 2997 chan = hdev->smp_data; 2998 hdev->smp_data = NULL; 2999 smp_del_chan(chan); 3000 return err; 3001 } 3002 3003 hdev->smp_bredr_data = chan; 3004 3005 return 0; 3006 } 3007 3008 void smp_unregister(struct hci_dev *hdev) 3009 { 3010 struct l2cap_chan *chan; 3011 3012 if (hdev->smp_bredr_data) { 3013 chan = hdev->smp_bredr_data; 3014 hdev->smp_bredr_data = NULL; 3015 smp_del_chan(chan); 3016 } 3017 3018 if (hdev->smp_data) { 3019 chan = hdev->smp_data; 3020 hdev->smp_data = NULL; 3021 smp_del_chan(chan); 3022 } 3023 } 3024