net/bluetooth/smp.c

   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 <net/bluetooth/bluetooth.h>
  24 #include <net/bluetooth/hci_core.h>
  25 #include <net/bluetooth/l2cap.h>
  26 #include <net/bluetooth/smp.h>
  27 #include <linux/crypto.h>
  28 #include <linux/scatterlist.h>
  29 #include <crypto/b128ops.h>
  30
  31 #define SMP_TIMEOUT 30000 /* 30 seconds */
  32
  33 static inline void swap128(u8 src[16], u8 dst[16])
  34 {
  35         int i;
  36         for (i = 0; i < 16; i++)
  37                 dst[15 - i] = src[i];
  38 }
  39
  40 static inline void swap56(u8 src[7], u8 dst[7])
  41 {
  42         int i;
  43         for (i = 0; i < 7; i++)
  44                 dst[6 - i] = src[i];
  45 }
  46
  47 static int smp_e(struct crypto_blkcipher *tfm, const u8 *k, u8 *r)
  48 {
  49         struct blkcipher_desc desc;
  50         struct scatterlist sg;
  51         int err, iv_len;
  52         unsigned char iv[128];
  53
  54         if (tfm == NULL) {
  55                 BT_ERR("tfm %p", tfm);
  56                 return -EINVAL;
  57         }
  58
  59         desc.tfm = tfm;
  60         desc.flags = 0;
  61
  62         err = crypto_blkcipher_setkey(tfm, k, 16);
  63         if (err) {
  64                 BT_ERR("cipher setkey failed: %d", err);
  65                 return err;
  66         }
  67
  68         sg_init_one(&sg, r, 16);
  69
  70         iv_len = crypto_blkcipher_ivsize(tfm);
  71         if (iv_len) {
  72                 memset(&iv, 0xff, iv_len);
  73                 crypto_blkcipher_set_iv(tfm, iv, iv_len);
  74         }
  75
  76         err = crypto_blkcipher_encrypt(&desc, &sg, &sg, 16);
  77         if (err)
  78                 BT_ERR("Encrypt data error %d", err);
  79
  80         return err;
  81 }
  82
  83 static int smp_c1(struct crypto_blkcipher *tfm, u8 k[16], u8 r[16],
  84                 u8 preq[7], u8 pres[7], u8 _iat, bdaddr_t *ia,
  85                 u8 _rat, bdaddr_t *ra, u8 res[16])
  86 {
  87         u8 p1[16], p2[16];
  88         int err;
  89
  90         memset(p1, 0, 16);
  91
  92         /* p1 = pres || preq || _rat || _iat */
  93         swap56(pres, p1);
  94         swap56(preq, p1 + 7);
  95         p1[14] = _rat;
  96         p1[15] = _iat;
  97
  98         memset(p2, 0, 16);
  99
 100         /* p2 = padding || ia || ra */
 101         baswap((bdaddr_t *) (p2 + 4), ia);
 102         baswap((bdaddr_t *) (p2 + 10), ra);
 103
 104         /* res = r XOR p1 */
 105         u128_xor((u128 *) res, (u128 *) r, (u128 *) p1);
 106
 107         /* res = e(k, res) */
 108         err = smp_e(tfm, k, res);
 109         if (err) {
 110                 BT_ERR("Encrypt data error");
 111                 return err;
 112         }
 113
 114         /* res = res XOR p2 */
 115         u128_xor((u128 *) res, (u128 *) res, (u128 *) p2);
 116
 117         /* res = e(k, res) */
 118         err = smp_e(tfm, k, res);
 119         if (err)
 120                 BT_ERR("Encrypt data error");
 121
 122         return err;
 123 }
 124
 125 static int smp_s1(struct crypto_blkcipher *tfm, u8 k[16],
 126                         u8 r1[16], u8 r2[16], u8 _r[16])
 127 {
 128         int err;
 129
 130         /* Just least significant octets from r1 and r2 are considered */
 131         memcpy(_r, r1 + 8, 8);
 132         memcpy(_r + 8, r2 + 8, 8);
 133
 134         err = smp_e(tfm, k, _r);
 135         if (err)
 136                 BT_ERR("Encrypt data error");
 137
 138         return err;
 139 }
 140
 141 static int smp_rand(u8 *buf)
 142 {
 143         get_random_bytes(buf, 16);
 144
 145         return 0;
 146 }
 147
 148 static struct sk_buff *smp_build_cmd(struct l2cap_conn *conn, u8 code,
 149                                                 u16 dlen, void *data)
 150 {
 151         struct sk_buff *skb;
 152         struct l2cap_hdr *lh;
 153         int len;
 154
 155         len = L2CAP_HDR_SIZE + sizeof(code) + dlen;
 156
 157         if (len > conn->mtu)
 158                 return NULL;
 159
 160         skb = bt_skb_alloc(len, GFP_ATOMIC);
 161         if (!skb)
 162                 return NULL;
 163
 164         lh = (struct l2cap_hdr *) skb_put(skb, L2CAP_HDR_SIZE);
 165         lh->len = cpu_to_le16(sizeof(code) + dlen);
 166         lh->cid = cpu_to_le16(L2CAP_CID_SMP);
 167
 168         memcpy(skb_put(skb, sizeof(code)), &code, sizeof(code));
 169
 170         memcpy(skb_put(skb, dlen), data, dlen);
 171
 172         return skb;
 173 }
 174
 175 static void smp_send_cmd(struct l2cap_conn *conn, u8 code, u16 len, void *data)
 176 {
 177         struct sk_buff *skb = smp_build_cmd(conn, code, len, data);
 178
 179         BT_DBG("code 0x%2.2x", code);
 180
 181         if (!skb)
 182                 return;
 183
 184         hci_send_acl(conn->hcon, skb, 0);
 185 }
 186
 187 static __u8 seclevel_to_authreq(__u8 level)
 188 {
 189         switch (level) {
 190         case BT_SECURITY_HIGH:
 191                 /* Right now we don't support bonding */
 192                 return SMP_AUTH_MITM;
 193
 194         default:
 195                 return SMP_AUTH_NONE;
 196         }
 197 }
 198
 199 static void build_pairing_cmd(struct l2cap_conn *conn,
 200                                 struct smp_cmd_pairing *req,
 201                                 struct smp_cmd_pairing *rsp,
 202                                 __u8 authreq)
 203 {
 204         u8 dist_keys;
 205
 206         dist_keys = 0;
 207         if (test_bit(HCI_PAIRABLE, &conn->hcon->hdev->flags)) {
 208                 dist_keys = SMP_DIST_ENC_KEY | SMP_DIST_ID_KEY | SMP_DIST_SIGN;
 209                 authreq |= SMP_AUTH_BONDING;
 210         }
 211
 212         if (rsp == NULL) {
 213                 req->io_capability = conn->hcon->io_capability;
 214                 req->oob_flag = SMP_OOB_NOT_PRESENT;
 215                 req->max_key_size = SMP_MAX_ENC_KEY_SIZE;
 216                 req->init_key_dist = dist_keys;
 217                 req->resp_key_dist = dist_keys;
 218                 req->auth_req = authreq;
 219                 return;
 220         }
 221
 222         rsp->io_capability = conn->hcon->io_capability;
 223         rsp->oob_flag = SMP_OOB_NOT_PRESENT;
 224         rsp->max_key_size = SMP_MAX_ENC_KEY_SIZE;
 225         rsp->init_key_dist = req->init_key_dist & dist_keys;
 226         rsp->resp_key_dist = req->resp_key_dist & dist_keys;
 227         rsp->auth_req = authreq;
 228 }
 229
 230 static u8 check_enc_key_size(struct l2cap_conn *conn, __u8 max_key_size)
 231 {
 232         if ((max_key_size > SMP_MAX_ENC_KEY_SIZE) ||
 233                         (max_key_size < SMP_MIN_ENC_KEY_SIZE))
 234                 return SMP_ENC_KEY_SIZE;
 235
 236         conn->smp_key_size = max_key_size;
 237
 238         return 0;
 239 }
 240
 241 static u8 smp_cmd_pairing_req(struct l2cap_conn *conn, struct sk_buff *skb)
 242 {
 243         struct smp_cmd_pairing rsp, *req = (void *) skb->data;
 244         u8 key_size;
 245
 246         BT_DBG("conn %p", conn);
 247
 248         conn->preq[0] = SMP_CMD_PAIRING_REQ;
 249         memcpy(&conn->preq[1], req, sizeof(*req));
 250         skb_pull(skb, sizeof(*req));
 251
 252         if (req->oob_flag)
 253                 return SMP_OOB_NOT_AVAIL;
 254
 255         /* We didn't start the pairing, so no requirements */
 256         build_pairing_cmd(conn, req, &rsp, SMP_AUTH_NONE);
 257
 258         key_size = min(req->max_key_size, rsp.max_key_size);
 259         if (check_enc_key_size(conn, key_size))
 260                 return SMP_ENC_KEY_SIZE;
 261
 262         /* Just works */
 263         memset(conn->tk, 0, sizeof(conn->tk));
 264
 265         conn->prsp[0] = SMP_CMD_PAIRING_RSP;
 266         memcpy(&conn->prsp[1], &rsp, sizeof(rsp));
 267
 268         smp_send_cmd(conn, SMP_CMD_PAIRING_RSP, sizeof(rsp), &rsp);
 269
 270         mod_timer(&conn->security_timer, jiffies +
 271                                         msecs_to_jiffies(SMP_TIMEOUT));
 272
 273         return 0;
 274 }
 275
 276 static u8 smp_cmd_pairing_rsp(struct l2cap_conn *conn, struct sk_buff *skb)
 277 {
 278         struct smp_cmd_pairing *req, *rsp = (void *) skb->data;
 279         struct smp_cmd_pairing_confirm cp;
 280         struct crypto_blkcipher *tfm = conn->hcon->hdev->tfm;
 281         int ret;
 282         u8 res[16], key_size;
 283
 284         BT_DBG("conn %p", conn);
 285
 286         skb_pull(skb, sizeof(*rsp));
 287
 288         req = (void *) &conn->preq[1];
 289
 290         key_size = min(req->max_key_size, rsp->max_key_size);
 291         if (check_enc_key_size(conn, key_size))
 292                 return SMP_ENC_KEY_SIZE;
 293
 294         if (rsp->oob_flag)
 295                 return SMP_OOB_NOT_AVAIL;
 296
 297         /* Just works */
 298         memset(conn->tk, 0, sizeof(conn->tk));
 299
 300         conn->prsp[0] = SMP_CMD_PAIRING_RSP;
 301         memcpy(&conn->prsp[1], rsp, sizeof(*rsp));
 302
 303         ret = smp_rand(conn->prnd);
 304         if (ret)
 305                 return SMP_UNSPECIFIED;
 306
 307         ret = smp_c1(tfm, conn->tk, conn->prnd, conn->preq, conn->prsp, 0,
 308                         conn->src, conn->hcon->dst_type, conn->dst, res);
 309         if (ret)
 310                 return SMP_UNSPECIFIED;
 311
 312         swap128(res, cp.confirm_val);
 313
 314         smp_send_cmd(conn, SMP_CMD_PAIRING_CONFIRM, sizeof(cp), &cp);
 315
 316         return 0;
 317 }
 318
 319 static u8 smp_cmd_pairing_confirm(struct l2cap_conn *conn, struct sk_buff *skb)
 320 {
 321         struct crypto_blkcipher *tfm = conn->hcon->hdev->tfm;
 322
 323         BT_DBG("conn %p %s", conn, conn->hcon->out ? "master" : "slave");
 324
 325         memcpy(conn->pcnf, skb->data, sizeof(conn->pcnf));
 326         skb_pull(skb, sizeof(conn->pcnf));
 327
 328         if (conn->hcon->out) {
 329                 u8 random[16];
 330
 331                 swap128(conn->prnd, random);
 332                 smp_send_cmd(conn, SMP_CMD_PAIRING_RANDOM, sizeof(random),
 333                                                                 random);
 334         } else {
 335                 struct smp_cmd_pairing_confirm cp;
 336                 int ret;
 337                 u8 res[16];
 338
 339                 ret = smp_rand(conn->prnd);
 340                 if (ret)
 341                         return SMP_UNSPECIFIED;
 342
 343                 ret = smp_c1(tfm, conn->tk, conn->prnd, conn->preq, conn->prsp,
 344                                                 conn->hcon->dst_type, conn->dst,
 345                                                 0, conn->src, res);
 346                 if (ret)
 347                         return SMP_CONFIRM_FAILED;
 348
 349                 swap128(res, cp.confirm_val);
 350
 351                 smp_send_cmd(conn, SMP_CMD_PAIRING_CONFIRM, sizeof(cp), &cp);
 352         }
 353
 354         mod_timer(&conn->security_timer, jiffies +
 355                                         msecs_to_jiffies(SMP_TIMEOUT));
 356
 357         return 0;
 358 }
 359
 360 static u8 smp_cmd_pairing_random(struct l2cap_conn *conn, struct sk_buff *skb)
 361 {
 362         struct hci_conn *hcon = conn->hcon;
 363         struct crypto_blkcipher *tfm = hcon->hdev->tfm;
 364         int ret;
 365         u8 key[16], res[16], random[16], confirm[16];
 366
 367         swap128(skb->data, random);
 368         skb_pull(skb, sizeof(random));
 369
 370         memset(hcon->ltk, 0, sizeof(hcon->ltk));
 371
 372         if (conn->hcon->out)
 373                 ret = smp_c1(tfm, conn->tk, random, conn->preq, conn->prsp, 0,
 374                                 conn->src, conn->hcon->dst_type, conn->dst,
 375                                 res);
 376         else
 377                 ret = smp_c1(tfm, conn->tk, random, conn->preq, conn->prsp,
 378                                 conn->hcon->dst_type, conn->dst, 0, conn->src,
 379                                 res);
 380         if (ret)
 381                 return SMP_UNSPECIFIED;
 382
 383         BT_DBG("conn %p %s", conn, conn->hcon->out ? "master" : "slave");
 384
 385         swap128(res, confirm);
 386
 387         if (memcmp(conn->pcnf, confirm, sizeof(conn->pcnf)) != 0) {
 388                 BT_ERR("Pairing failed (confirmation values mismatch)");
 389                 return SMP_CONFIRM_FAILED;
 390         }
 391
 392         if (conn->hcon->out) {
 393                 u8 stk[16], rand[8];
 394                 __le16 ediv;
 395
 396                 memset(rand, 0, sizeof(rand));
 397                 ediv = 0;
 398
 399                 smp_s1(tfm, conn->tk, random, conn->prnd, key);
 400                 swap128(key, stk);
 401
 402                 memset(stk + conn->smp_key_size, 0,
 403                                 SMP_MAX_ENC_KEY_SIZE - conn->smp_key_size);
 404
 405                 hci_le_start_enc(hcon, ediv, rand, stk);
 406         } else {
 407                 u8 stk[16], r[16], rand[8];
 408                 __le16 ediv;
 409
 410                 memset(rand, 0, sizeof(rand));
 411                 ediv = 0;
 412
 413                 swap128(conn->prnd, r);
 414                 smp_send_cmd(conn, SMP_CMD_PAIRING_RANDOM, sizeof(r), r);
 415
 416                 smp_s1(tfm, conn->tk, conn->prnd, random, key);
 417                 swap128(key, stk);
 418
 419                 memset(stk + conn->smp_key_size, 0,
 420                                 SMP_MAX_ENC_KEY_SIZE - conn->smp_key_size);
 421
 422                 hci_add_ltk(conn->hcon->hdev, 0, conn->dst, ediv, rand, stk);
 423         }
 424
 425         return 0;
 426 }
 427
 428 static u8 smp_cmd_security_req(struct l2cap_conn *conn, struct sk_buff *skb)
 429 {
 430         struct smp_cmd_security_req *rp = (void *) skb->data;
 431         struct smp_cmd_pairing cp;
 432         struct hci_conn *hcon = conn->hcon;
 433
 434         BT_DBG("conn %p", conn);
 435
 436         if (test_bit(HCI_CONN_ENCRYPT_PEND, &hcon->pend))
 437                 return 0;
 438
 439         skb_pull(skb, sizeof(*rp));
 440
 441         memset(&cp, 0, sizeof(cp));
 442         build_pairing_cmd(conn, &cp, NULL, rp->auth_req);
 443
 444         conn->preq[0] = SMP_CMD_PAIRING_REQ;
 445         memcpy(&conn->preq[1], &cp, sizeof(cp));
 446
 447         smp_send_cmd(conn, SMP_CMD_PAIRING_REQ, sizeof(cp), &cp);
 448
 449         mod_timer(&conn->security_timer, jiffies +
 450                                         msecs_to_jiffies(SMP_TIMEOUT));
 451
 452         set_bit(HCI_CONN_ENCRYPT_PEND, &hcon->pend);
 453
 454         return 0;
 455 }
 456
 457 int smp_conn_security(struct l2cap_conn *conn, __u8 sec_level)
 458 {
 459         struct hci_conn *hcon = conn->hcon;
 460         __u8 authreq;
 461
 462         BT_DBG("conn %p hcon %p level 0x%2.2x", conn, hcon, sec_level);
 463
 464         if (!lmp_host_le_capable(hcon->hdev))
 465                 return 1;
 466
 467         if (IS_ERR(hcon->hdev->tfm))
 468                 return 1;
 469
 470         if (test_bit(HCI_CONN_ENCRYPT_PEND, &hcon->pend))
 471                 return 0;
 472
 473         if (sec_level == BT_SECURITY_LOW)
 474                 return 1;
 475
 476         if (hcon->sec_level >= sec_level)
 477                 return 1;
 478
 479         authreq = seclevel_to_authreq(sec_level);
 480
 481         if (hcon->link_mode & HCI_LM_MASTER) {
 482                 struct smp_cmd_pairing cp;
 483                 struct link_key *key;
 484
 485                 key = hci_find_link_key_type(hcon->hdev, conn->dst,
 486                                                         HCI_LK_SMP_LTK);
 487                 if (key) {
 488                         struct key_master_id *master = (void *) key->data;
 489
 490                         hci_le_start_enc(hcon, master->ediv, master->rand,
 491                                                                 key->val);
 492                         goto done;
 493                 }
 494
 495                 build_pairing_cmd(conn, &cp, NULL, authreq);
 496                 conn->preq[0] = SMP_CMD_PAIRING_REQ;
 497                 memcpy(&conn->preq[1], &cp, sizeof(cp));
 498
 499                 mod_timer(&conn->security_timer, jiffies +
 500                                         msecs_to_jiffies(SMP_TIMEOUT));
 501
 502                 smp_send_cmd(conn, SMP_CMD_PAIRING_REQ, sizeof(cp), &cp);
 503         } else {
 504                 struct smp_cmd_security_req cp;
 505                 cp.auth_req = authreq;
 506                 smp_send_cmd(conn, SMP_CMD_SECURITY_REQ, sizeof(cp), &cp);
 507         }
 508
 509 done:
 510         hcon->pending_sec_level = sec_level;
 511         set_bit(HCI_CONN_ENCRYPT_PEND, &hcon->pend);
 512
 513         return 0;
 514 }
 515
 516 static int smp_cmd_encrypt_info(struct l2cap_conn *conn, struct sk_buff *skb)
 517 {
 518         struct smp_cmd_encrypt_info *rp = (void *) skb->data;
 519
 520         skb_pull(skb, sizeof(*rp));
 521
 522         memcpy(conn->tk, rp->ltk, sizeof(conn->tk));
 523
 524         return 0;
 525 }
 526
 527 static int smp_cmd_master_ident(struct l2cap_conn *conn, struct sk_buff *skb)
 528 {
 529         struct smp_cmd_master_ident *rp = (void *) skb->data;
 530
 531         skb_pull(skb, sizeof(*rp));
 532
 533         hci_add_ltk(conn->hcon->hdev, 1, conn->src, rp->ediv,
 534                                                 rp->rand, conn->tk);
 535
 536         smp_distribute_keys(conn, 1);
 537
 538         return 0;
 539 }
 540
 541 int smp_sig_channel(struct l2cap_conn *conn, struct sk_buff *skb)
 542 {
 543         __u8 code = skb->data[0];
 544         __u8 reason;
 545         int err = 0;
 546
 547         if (!lmp_host_le_capable(conn->hcon->hdev)) {
 548                 err = -ENOTSUPP;
 549                 reason = SMP_PAIRING_NOTSUPP;
 550                 goto done;
 551         }
 552
 553         if (IS_ERR(conn->hcon->hdev->tfm)) {
 554                 err = PTR_ERR(conn->hcon->hdev->tfm);
 555                 reason = SMP_PAIRING_NOTSUPP;
 556                 goto done;
 557         }
 558
 559         skb_pull(skb, sizeof(code));
 560
 561         switch (code) {
 562         case SMP_CMD_PAIRING_REQ:
 563                 reason = smp_cmd_pairing_req(conn, skb);
 564                 break;
 565
 566         case SMP_CMD_PAIRING_FAIL:
 567                 reason = 0;
 568                 err = -EPERM;
 569                 break;
 570
 571         case SMP_CMD_PAIRING_RSP:
 572                 reason = smp_cmd_pairing_rsp(conn, skb);
 573                 break;
 574
 575         case SMP_CMD_SECURITY_REQ:
 576                 reason = smp_cmd_security_req(conn, skb);
 577                 break;
 578
 579         case SMP_CMD_PAIRING_CONFIRM:
 580                 reason = smp_cmd_pairing_confirm(conn, skb);
 581                 break;
 582
 583         case SMP_CMD_PAIRING_RANDOM:
 584                 reason = smp_cmd_pairing_random(conn, skb);
 585                 break;
 586
 587         case SMP_CMD_ENCRYPT_INFO:
 588                 reason = smp_cmd_encrypt_info(conn, skb);
 589                 break;
 590
 591         case SMP_CMD_MASTER_IDENT:
 592                 reason = smp_cmd_master_ident(conn, skb);
 593                 break;
 594
 595         case SMP_CMD_IDENT_INFO:
 596         case SMP_CMD_IDENT_ADDR_INFO:
 597         case SMP_CMD_SIGN_INFO:
 598                 /* Just ignored */
 599                 reason = 0;
 600                 break;
 601
 602         default:
 603                 BT_DBG("Unknown command code 0x%2.2x", code);
 604
 605                 reason = SMP_CMD_NOTSUPP;
 606                 err = -EOPNOTSUPP;
 607                 goto done;
 608         }
 609
 610 done:
 611         if (reason)
 612                 smp_send_cmd(conn, SMP_CMD_PAIRING_FAIL, sizeof(reason),
 613                                                                 &reason);
 614
 615         kfree_skb(skb);
 616         return err;
 617 }
 618
 619 int smp_distribute_keys(struct l2cap_conn *conn, __u8 force)
 620 {
 621         struct smp_cmd_pairing *req, *rsp;
 622         __u8 *keydist;
 623
 624         BT_DBG("conn %p force %d", conn, force);
 625
 626         if (IS_ERR(conn->hcon->hdev->tfm))
 627                 return PTR_ERR(conn->hcon->hdev->tfm);
 628
 629         rsp = (void *) &conn->prsp[1];
 630
 631         /* The responder sends its keys first */
 632         if (!force && conn->hcon->out && (rsp->resp_key_dist & 0x07))
 633                 return 0;
 634
 635         req = (void *) &conn->preq[1];
 636
 637         if (conn->hcon->out) {
 638                 keydist = &rsp->init_key_dist;
 639                 *keydist &= req->init_key_dist;
 640         } else {
 641                 keydist = &rsp->resp_key_dist;
 642                 *keydist &= req->resp_key_dist;
 643         }
 644
 645
 646         BT_DBG("keydist 0x%x", *keydist);
 647
 648         if (*keydist & SMP_DIST_ENC_KEY) {
 649                 struct smp_cmd_encrypt_info enc;
 650                 struct smp_cmd_master_ident ident;
 651                 __le16 ediv;
 652
 653                 get_random_bytes(enc.ltk, sizeof(enc.ltk));
 654                 get_random_bytes(&ediv, sizeof(ediv));
 655                 get_random_bytes(ident.rand, sizeof(ident.rand));
 656
 657                 smp_send_cmd(conn, SMP_CMD_ENCRYPT_INFO, sizeof(enc), &enc);
 658
 659                 hci_add_ltk(conn->hcon->hdev, 1, conn->dst, ediv,
 660                                                         ident.rand, enc.ltk);
 661
 662                 ident.ediv = cpu_to_le16(ediv);
 663
 664                 smp_send_cmd(conn, SMP_CMD_MASTER_IDENT, sizeof(ident), &ident);
 665
 666                 *keydist &= ~SMP_DIST_ENC_KEY;
 667         }
 668
 669         if (*keydist & SMP_DIST_ID_KEY) {
 670                 struct smp_cmd_ident_addr_info addrinfo;
 671                 struct smp_cmd_ident_info idinfo;
 672
 673                 /* Send a dummy key */
 674                 get_random_bytes(idinfo.irk, sizeof(idinfo.irk));
 675
 676                 smp_send_cmd(conn, SMP_CMD_IDENT_INFO, sizeof(idinfo), &idinfo);
 677
 678                 /* Just public address */
 679                 memset(&addrinfo, 0, sizeof(addrinfo));
 680                 bacpy(&addrinfo.bdaddr, conn->src);
 681
 682                 smp_send_cmd(conn, SMP_CMD_IDENT_ADDR_INFO, sizeof(addrinfo),
 683                                                                 &addrinfo);
 684
 685                 *keydist &= ~SMP_DIST_ID_KEY;
 686         }
 687
 688         if (*keydist & SMP_DIST_SIGN) {
 689                 struct smp_cmd_sign_info sign;
 690
 691                 /* Send a dummy key */
 692                 get_random_bytes(sign.csrk, sizeof(sign.csrk));
 693
 694                 smp_send_cmd(conn, SMP_CMD_SIGN_INFO, sizeof(sign), &sign);
 695
 696                 *keydist &= ~SMP_DIST_SIGN;
 697         }
 698
 699         return 0;
 700 }