1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Management Component Transport Protocol (MCTP) 4 * 5 * Copyright (c) 2021 Code Construct 6 * Copyright (c) 2021 Google 7 */ 8 9 #include <linux/compat.h> 10 #include <linux/if_arp.h> 11 #include <linux/net.h> 12 #include <linux/mctp.h> 13 #include <linux/module.h> 14 #include <linux/socket.h> 15 16 #include <net/mctp.h> 17 #include <net/mctpdevice.h> 18 #include <net/sock.h> 19 20 #define CREATE_TRACE_POINTS 21 #include <trace/events/mctp.h> 22 23 /* socket implementation */ 24 25 static void mctp_sk_expire_keys(struct timer_list *timer); 26 27 static int mctp_release(struct socket *sock) 28 { 29 struct sock *sk = sock->sk; 30 31 if (sk) { 32 sock->sk = NULL; 33 sk->sk_prot->close(sk, 0); 34 } 35 36 return 0; 37 } 38 39 /* Generic sockaddr checks, padding checks only so far */ 40 static bool mctp_sockaddr_is_ok(const struct sockaddr_mctp *addr) 41 { 42 return !addr->__smctp_pad0 && !addr->__smctp_pad1; 43 } 44 45 static bool mctp_sockaddr_ext_is_ok(const struct sockaddr_mctp_ext *addr) 46 { 47 return !addr->__smctp_pad0[0] && 48 !addr->__smctp_pad0[1] && 49 !addr->__smctp_pad0[2]; 50 } 51 52 static int mctp_bind(struct socket *sock, struct sockaddr *addr, int addrlen) 53 { 54 struct sock *sk = sock->sk; 55 struct mctp_sock *msk = container_of(sk, struct mctp_sock, sk); 56 struct sockaddr_mctp *smctp; 57 int rc; 58 59 if (addrlen < sizeof(*smctp)) 60 return -EINVAL; 61 62 if (addr->sa_family != AF_MCTP) 63 return -EAFNOSUPPORT; 64 65 if (!capable(CAP_NET_BIND_SERVICE)) 66 return -EACCES; 67 68 /* it's a valid sockaddr for MCTP, cast and do protocol checks */ 69 smctp = (struct sockaddr_mctp *)addr; 70 71 if (!mctp_sockaddr_is_ok(smctp)) 72 return -EINVAL; 73 74 lock_sock(sk); 75 76 /* TODO: allow rebind */ 77 if (sk_hashed(sk)) { 78 rc = -EADDRINUSE; 79 goto out_release; 80 } 81 msk->bind_net = smctp->smctp_network; 82 msk->bind_addr = smctp->smctp_addr.s_addr; 83 msk->bind_type = smctp->smctp_type & 0x7f; /* ignore the IC bit */ 84 85 rc = sk->sk_prot->hash(sk); 86 87 out_release: 88 release_sock(sk); 89 90 return rc; 91 } 92 93 static int mctp_sendmsg(struct socket *sock, struct msghdr *msg, size_t len) 94 { 95 DECLARE_SOCKADDR(struct sockaddr_mctp *, addr, msg->msg_name); 96 int rc, addrlen = msg->msg_namelen; 97 struct sock *sk = sock->sk; 98 struct mctp_sock *msk = container_of(sk, struct mctp_sock, sk); 99 struct mctp_skb_cb *cb; 100 struct mctp_route *rt; 101 struct sk_buff *skb = NULL; 102 int hlen; 103 104 if (addr) { 105 const u8 tagbits = MCTP_TAG_MASK | MCTP_TAG_OWNER | 106 MCTP_TAG_PREALLOC; 107 108 if (addrlen < sizeof(struct sockaddr_mctp)) 109 return -EINVAL; 110 if (addr->smctp_family != AF_MCTP) 111 return -EINVAL; 112 if (!mctp_sockaddr_is_ok(addr)) 113 return -EINVAL; 114 if (addr->smctp_tag & ~tagbits) 115 return -EINVAL; 116 /* can't preallocate a non-owned tag */ 117 if (addr->smctp_tag & MCTP_TAG_PREALLOC && 118 !(addr->smctp_tag & MCTP_TAG_OWNER)) 119 return -EINVAL; 120 121 } else { 122 /* TODO: connect()ed sockets */ 123 return -EDESTADDRREQ; 124 } 125 126 if (!capable(CAP_NET_RAW)) 127 return -EACCES; 128 129 if (addr->smctp_network == MCTP_NET_ANY) 130 addr->smctp_network = mctp_default_net(sock_net(sk)); 131 132 /* direct addressing */ 133 if (msk->addr_ext && addrlen >= sizeof(struct sockaddr_mctp_ext)) { 134 DECLARE_SOCKADDR(struct sockaddr_mctp_ext *, 135 extaddr, msg->msg_name); 136 struct net_device *dev; 137 138 rc = -EINVAL; 139 rcu_read_lock(); 140 dev = dev_get_by_index_rcu(sock_net(sk), extaddr->smctp_ifindex); 141 /* check for correct halen */ 142 if (dev && extaddr->smctp_halen == dev->addr_len) { 143 hlen = LL_RESERVED_SPACE(dev) + sizeof(struct mctp_hdr); 144 rc = 0; 145 } 146 rcu_read_unlock(); 147 if (rc) 148 goto err_free; 149 rt = NULL; 150 } else { 151 rt = mctp_route_lookup(sock_net(sk), addr->smctp_network, 152 addr->smctp_addr.s_addr); 153 if (!rt) { 154 rc = -EHOSTUNREACH; 155 goto err_free; 156 } 157 hlen = LL_RESERVED_SPACE(rt->dev->dev) + sizeof(struct mctp_hdr); 158 } 159 160 skb = sock_alloc_send_skb(sk, hlen + 1 + len, 161 msg->msg_flags & MSG_DONTWAIT, &rc); 162 if (!skb) 163 return rc; 164 165 skb_reserve(skb, hlen); 166 167 /* set type as fist byte in payload */ 168 *(u8 *)skb_put(skb, 1) = addr->smctp_type; 169 170 rc = memcpy_from_msg((void *)skb_put(skb, len), msg, len); 171 if (rc < 0) 172 goto err_free; 173 174 /* set up cb */ 175 cb = __mctp_cb(skb); 176 cb->net = addr->smctp_network; 177 178 if (!rt) { 179 /* fill extended address in cb */ 180 DECLARE_SOCKADDR(struct sockaddr_mctp_ext *, 181 extaddr, msg->msg_name); 182 183 if (!mctp_sockaddr_ext_is_ok(extaddr) || 184 extaddr->smctp_halen > sizeof(cb->haddr)) { 185 rc = -EINVAL; 186 goto err_free; 187 } 188 189 cb->ifindex = extaddr->smctp_ifindex; 190 /* smctp_halen is checked above */ 191 cb->halen = extaddr->smctp_halen; 192 memcpy(cb->haddr, extaddr->smctp_haddr, cb->halen); 193 } 194 195 rc = mctp_local_output(sk, rt, skb, addr->smctp_addr.s_addr, 196 addr->smctp_tag); 197 198 return rc ? : len; 199 200 err_free: 201 kfree_skb(skb); 202 return rc; 203 } 204 205 static int mctp_recvmsg(struct socket *sock, struct msghdr *msg, size_t len, 206 int flags) 207 { 208 DECLARE_SOCKADDR(struct sockaddr_mctp *, addr, msg->msg_name); 209 struct sock *sk = sock->sk; 210 struct mctp_sock *msk = container_of(sk, struct mctp_sock, sk); 211 struct sk_buff *skb; 212 size_t msglen; 213 u8 type; 214 int rc; 215 216 if (flags & ~(MSG_DONTWAIT | MSG_TRUNC | MSG_PEEK)) 217 return -EOPNOTSUPP; 218 219 skb = skb_recv_datagram(sk, flags, &rc); 220 if (!skb) 221 return rc; 222 223 if (!skb->len) { 224 rc = 0; 225 goto out_free; 226 } 227 228 /* extract message type, remove from data */ 229 type = *((u8 *)skb->data); 230 msglen = skb->len - 1; 231 232 if (len < msglen) 233 msg->msg_flags |= MSG_TRUNC; 234 else 235 len = msglen; 236 237 rc = skb_copy_datagram_msg(skb, 1, msg, len); 238 if (rc < 0) 239 goto out_free; 240 241 sock_recv_cmsgs(msg, sk, skb); 242 243 if (addr) { 244 struct mctp_skb_cb *cb = mctp_cb(skb); 245 /* TODO: expand mctp_skb_cb for header fields? */ 246 struct mctp_hdr *hdr = mctp_hdr(skb); 247 248 addr = msg->msg_name; 249 addr->smctp_family = AF_MCTP; 250 addr->__smctp_pad0 = 0; 251 addr->smctp_network = cb->net; 252 addr->smctp_addr.s_addr = hdr->src; 253 addr->smctp_type = type; 254 addr->smctp_tag = hdr->flags_seq_tag & 255 (MCTP_HDR_TAG_MASK | MCTP_HDR_FLAG_TO); 256 addr->__smctp_pad1 = 0; 257 msg->msg_namelen = sizeof(*addr); 258 259 if (msk->addr_ext) { 260 DECLARE_SOCKADDR(struct sockaddr_mctp_ext *, ae, 261 msg->msg_name); 262 msg->msg_namelen = sizeof(*ae); 263 ae->smctp_ifindex = cb->ifindex; 264 ae->smctp_halen = cb->halen; 265 memset(ae->__smctp_pad0, 0x0, sizeof(ae->__smctp_pad0)); 266 memset(ae->smctp_haddr, 0x0, sizeof(ae->smctp_haddr)); 267 memcpy(ae->smctp_haddr, cb->haddr, cb->halen); 268 } 269 } 270 271 rc = len; 272 273 if (flags & MSG_TRUNC) 274 rc = msglen; 275 276 out_free: 277 skb_free_datagram(sk, skb); 278 return rc; 279 } 280 281 /* We're done with the key; invalidate, stop reassembly, and remove from lists. 282 */ 283 static void __mctp_key_remove(struct mctp_sk_key *key, struct net *net, 284 unsigned long flags, unsigned long reason) 285 __releases(&key->lock) 286 __must_hold(&net->mctp.keys_lock) 287 { 288 struct sk_buff *skb; 289 290 trace_mctp_key_release(key, reason); 291 skb = key->reasm_head; 292 key->reasm_head = NULL; 293 key->reasm_dead = true; 294 key->valid = false; 295 mctp_dev_release_key(key->dev, key); 296 spin_unlock_irqrestore(&key->lock, flags); 297 298 if (!hlist_unhashed(&key->hlist)) { 299 hlist_del_init(&key->hlist); 300 hlist_del_init(&key->sklist); 301 /* unref for the lists */ 302 mctp_key_unref(key); 303 } 304 305 kfree_skb(skb); 306 } 307 308 static int mctp_setsockopt(struct socket *sock, int level, int optname, 309 sockptr_t optval, unsigned int optlen) 310 { 311 struct mctp_sock *msk = container_of(sock->sk, struct mctp_sock, sk); 312 int val; 313 314 if (level != SOL_MCTP) 315 return -EINVAL; 316 317 if (optname == MCTP_OPT_ADDR_EXT) { 318 if (optlen != sizeof(int)) 319 return -EINVAL; 320 if (copy_from_sockptr(&val, optval, sizeof(int))) 321 return -EFAULT; 322 msk->addr_ext = val; 323 return 0; 324 } 325 326 return -ENOPROTOOPT; 327 } 328 329 static int mctp_getsockopt(struct socket *sock, int level, int optname, 330 char __user *optval, int __user *optlen) 331 { 332 struct mctp_sock *msk = container_of(sock->sk, struct mctp_sock, sk); 333 int len, val; 334 335 if (level != SOL_MCTP) 336 return -EINVAL; 337 338 if (get_user(len, optlen)) 339 return -EFAULT; 340 341 if (optname == MCTP_OPT_ADDR_EXT) { 342 if (len != sizeof(int)) 343 return -EINVAL; 344 val = !!msk->addr_ext; 345 if (copy_to_user(optval, &val, len)) 346 return -EFAULT; 347 return 0; 348 } 349 350 return -EINVAL; 351 } 352 353 static int mctp_ioctl_alloctag(struct mctp_sock *msk, unsigned long arg) 354 { 355 struct net *net = sock_net(&msk->sk); 356 struct mctp_sk_key *key = NULL; 357 struct mctp_ioc_tag_ctl ctl; 358 unsigned long flags; 359 u8 tag; 360 361 if (copy_from_user(&ctl, (void __user *)arg, sizeof(ctl))) 362 return -EFAULT; 363 364 if (ctl.tag) 365 return -EINVAL; 366 367 if (ctl.flags) 368 return -EINVAL; 369 370 key = mctp_alloc_local_tag(msk, ctl.peer_addr, MCTP_ADDR_ANY, 371 true, &tag); 372 if (IS_ERR(key)) 373 return PTR_ERR(key); 374 375 ctl.tag = tag | MCTP_TAG_OWNER | MCTP_TAG_PREALLOC; 376 if (copy_to_user((void __user *)arg, &ctl, sizeof(ctl))) { 377 unsigned long fl2; 378 /* Unwind our key allocation: the keys list lock needs to be 379 * taken before the individual key locks, and we need a valid 380 * flags value (fl2) to pass to __mctp_key_remove, hence the 381 * second spin_lock_irqsave() rather than a plain spin_lock(). 382 */ 383 spin_lock_irqsave(&net->mctp.keys_lock, flags); 384 spin_lock_irqsave(&key->lock, fl2); 385 __mctp_key_remove(key, net, fl2, MCTP_TRACE_KEY_DROPPED); 386 mctp_key_unref(key); 387 spin_unlock_irqrestore(&net->mctp.keys_lock, flags); 388 return -EFAULT; 389 } 390 391 mctp_key_unref(key); 392 return 0; 393 } 394 395 static int mctp_ioctl_droptag(struct mctp_sock *msk, unsigned long arg) 396 { 397 struct net *net = sock_net(&msk->sk); 398 struct mctp_ioc_tag_ctl ctl; 399 unsigned long flags, fl2; 400 struct mctp_sk_key *key; 401 struct hlist_node *tmp; 402 int rc; 403 u8 tag; 404 405 if (copy_from_user(&ctl, (void __user *)arg, sizeof(ctl))) 406 return -EFAULT; 407 408 if (ctl.flags) 409 return -EINVAL; 410 411 /* Must be a local tag, TO set, preallocated */ 412 if ((ctl.tag & ~MCTP_TAG_MASK) != (MCTP_TAG_OWNER | MCTP_TAG_PREALLOC)) 413 return -EINVAL; 414 415 tag = ctl.tag & MCTP_TAG_MASK; 416 rc = -EINVAL; 417 418 spin_lock_irqsave(&net->mctp.keys_lock, flags); 419 hlist_for_each_entry_safe(key, tmp, &msk->keys, sklist) { 420 /* we do an irqsave here, even though we know the irq state, 421 * so we have the flags to pass to __mctp_key_remove 422 */ 423 spin_lock_irqsave(&key->lock, fl2); 424 if (key->manual_alloc && 425 ctl.peer_addr == key->peer_addr && 426 tag == key->tag) { 427 __mctp_key_remove(key, net, fl2, 428 MCTP_TRACE_KEY_DROPPED); 429 rc = 0; 430 } else { 431 spin_unlock_irqrestore(&key->lock, fl2); 432 } 433 } 434 spin_unlock_irqrestore(&net->mctp.keys_lock, flags); 435 436 return rc; 437 } 438 439 static int mctp_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg) 440 { 441 struct mctp_sock *msk = container_of(sock->sk, struct mctp_sock, sk); 442 443 switch (cmd) { 444 case SIOCMCTPALLOCTAG: 445 return mctp_ioctl_alloctag(msk, arg); 446 case SIOCMCTPDROPTAG: 447 return mctp_ioctl_droptag(msk, arg); 448 } 449 450 return -EINVAL; 451 } 452 453 #ifdef CONFIG_COMPAT 454 static int mctp_compat_ioctl(struct socket *sock, unsigned int cmd, 455 unsigned long arg) 456 { 457 void __user *argp = compat_ptr(arg); 458 459 switch (cmd) { 460 /* These have compatible ptr layouts */ 461 case SIOCMCTPALLOCTAG: 462 case SIOCMCTPDROPTAG: 463 return mctp_ioctl(sock, cmd, (unsigned long)argp); 464 } 465 466 return -ENOIOCTLCMD; 467 } 468 #endif 469 470 static const struct proto_ops mctp_dgram_ops = { 471 .family = PF_MCTP, 472 .release = mctp_release, 473 .bind = mctp_bind, 474 .connect = sock_no_connect, 475 .socketpair = sock_no_socketpair, 476 .accept = sock_no_accept, 477 .getname = sock_no_getname, 478 .poll = datagram_poll, 479 .ioctl = mctp_ioctl, 480 .gettstamp = sock_gettstamp, 481 .listen = sock_no_listen, 482 .shutdown = sock_no_shutdown, 483 .setsockopt = mctp_setsockopt, 484 .getsockopt = mctp_getsockopt, 485 .sendmsg = mctp_sendmsg, 486 .recvmsg = mctp_recvmsg, 487 .mmap = sock_no_mmap, 488 .sendpage = sock_no_sendpage, 489 #ifdef CONFIG_COMPAT 490 .compat_ioctl = mctp_compat_ioctl, 491 #endif 492 }; 493 494 static void mctp_sk_expire_keys(struct timer_list *timer) 495 { 496 struct mctp_sock *msk = container_of(timer, struct mctp_sock, 497 key_expiry); 498 struct net *net = sock_net(&msk->sk); 499 unsigned long next_expiry, flags, fl2; 500 struct mctp_sk_key *key; 501 struct hlist_node *tmp; 502 bool next_expiry_valid = false; 503 504 spin_lock_irqsave(&net->mctp.keys_lock, flags); 505 506 hlist_for_each_entry_safe(key, tmp, &msk->keys, sklist) { 507 /* don't expire. manual_alloc is immutable, no locking 508 * required. 509 */ 510 if (key->manual_alloc) 511 continue; 512 513 spin_lock_irqsave(&key->lock, fl2); 514 if (!time_after_eq(key->expiry, jiffies)) { 515 __mctp_key_remove(key, net, fl2, 516 MCTP_TRACE_KEY_TIMEOUT); 517 continue; 518 } 519 520 if (next_expiry_valid) { 521 if (time_before(key->expiry, next_expiry)) 522 next_expiry = key->expiry; 523 } else { 524 next_expiry = key->expiry; 525 next_expiry_valid = true; 526 } 527 spin_unlock_irqrestore(&key->lock, fl2); 528 } 529 530 spin_unlock_irqrestore(&net->mctp.keys_lock, flags); 531 532 if (next_expiry_valid) 533 mod_timer(timer, next_expiry); 534 } 535 536 static int mctp_sk_init(struct sock *sk) 537 { 538 struct mctp_sock *msk = container_of(sk, struct mctp_sock, sk); 539 540 INIT_HLIST_HEAD(&msk->keys); 541 timer_setup(&msk->key_expiry, mctp_sk_expire_keys, 0); 542 return 0; 543 } 544 545 static void mctp_sk_close(struct sock *sk, long timeout) 546 { 547 sk_common_release(sk); 548 } 549 550 static int mctp_sk_hash(struct sock *sk) 551 { 552 struct net *net = sock_net(sk); 553 554 mutex_lock(&net->mctp.bind_lock); 555 sk_add_node_rcu(sk, &net->mctp.binds); 556 mutex_unlock(&net->mctp.bind_lock); 557 558 return 0; 559 } 560 561 static void mctp_sk_unhash(struct sock *sk) 562 { 563 struct mctp_sock *msk = container_of(sk, struct mctp_sock, sk); 564 struct net *net = sock_net(sk); 565 unsigned long flags, fl2; 566 struct mctp_sk_key *key; 567 struct hlist_node *tmp; 568 569 /* remove from any type-based binds */ 570 mutex_lock(&net->mctp.bind_lock); 571 sk_del_node_init_rcu(sk); 572 mutex_unlock(&net->mctp.bind_lock); 573 574 /* remove tag allocations */ 575 spin_lock_irqsave(&net->mctp.keys_lock, flags); 576 hlist_for_each_entry_safe(key, tmp, &msk->keys, sklist) { 577 spin_lock_irqsave(&key->lock, fl2); 578 __mctp_key_remove(key, net, fl2, MCTP_TRACE_KEY_CLOSED); 579 } 580 sock_set_flag(sk, SOCK_DEAD); 581 spin_unlock_irqrestore(&net->mctp.keys_lock, flags); 582 583 /* Since there are no more tag allocations (we have removed all of the 584 * keys), stop any pending expiry events. the timer cannot be re-queued 585 * as the sk is no longer observable 586 */ 587 del_timer_sync(&msk->key_expiry); 588 } 589 590 static void mctp_sk_destruct(struct sock *sk) 591 { 592 skb_queue_purge(&sk->sk_receive_queue); 593 } 594 595 static struct proto mctp_proto = { 596 .name = "MCTP", 597 .owner = THIS_MODULE, 598 .obj_size = sizeof(struct mctp_sock), 599 .init = mctp_sk_init, 600 .close = mctp_sk_close, 601 .hash = mctp_sk_hash, 602 .unhash = mctp_sk_unhash, 603 }; 604 605 static int mctp_pf_create(struct net *net, struct socket *sock, 606 int protocol, int kern) 607 { 608 const struct proto_ops *ops; 609 struct proto *proto; 610 struct sock *sk; 611 int rc; 612 613 if (protocol) 614 return -EPROTONOSUPPORT; 615 616 /* only datagram sockets are supported */ 617 if (sock->type != SOCK_DGRAM) 618 return -ESOCKTNOSUPPORT; 619 620 proto = &mctp_proto; 621 ops = &mctp_dgram_ops; 622 623 sock->state = SS_UNCONNECTED; 624 sock->ops = ops; 625 626 sk = sk_alloc(net, PF_MCTP, GFP_KERNEL, proto, kern); 627 if (!sk) 628 return -ENOMEM; 629 630 sock_init_data(sock, sk); 631 sk->sk_destruct = mctp_sk_destruct; 632 633 rc = 0; 634 if (sk->sk_prot->init) 635 rc = sk->sk_prot->init(sk); 636 637 if (rc) 638 goto err_sk_put; 639 640 return 0; 641 642 err_sk_put: 643 sock_orphan(sk); 644 sock_put(sk); 645 return rc; 646 } 647 648 static struct net_proto_family mctp_pf = { 649 .family = PF_MCTP, 650 .create = mctp_pf_create, 651 .owner = THIS_MODULE, 652 }; 653 654 static __init int mctp_init(void) 655 { 656 int rc; 657 658 /* ensure our uapi tag definitions match the header format */ 659 BUILD_BUG_ON(MCTP_TAG_OWNER != MCTP_HDR_FLAG_TO); 660 BUILD_BUG_ON(MCTP_TAG_MASK != MCTP_HDR_TAG_MASK); 661 662 pr_info("mctp: management component transport protocol core\n"); 663 664 rc = sock_register(&mctp_pf); 665 if (rc) 666 return rc; 667 668 rc = proto_register(&mctp_proto, 0); 669 if (rc) 670 goto err_unreg_sock; 671 672 rc = mctp_routes_init(); 673 if (rc) 674 goto err_unreg_proto; 675 676 rc = mctp_neigh_init(); 677 if (rc) 678 goto err_unreg_routes; 679 680 mctp_device_init(); 681 682 return 0; 683 684 err_unreg_routes: 685 mctp_routes_exit(); 686 err_unreg_proto: 687 proto_unregister(&mctp_proto); 688 err_unreg_sock: 689 sock_unregister(PF_MCTP); 690 691 return rc; 692 } 693 694 static __exit void mctp_exit(void) 695 { 696 mctp_device_exit(); 697 mctp_neigh_exit(); 698 mctp_routes_exit(); 699 proto_unregister(&mctp_proto); 700 sock_unregister(PF_MCTP); 701 } 702 703 subsys_initcall(mctp_init); 704 module_exit(mctp_exit); 705 706 MODULE_DESCRIPTION("MCTP core"); 707 MODULE_LICENSE("GPL v2"); 708 MODULE_AUTHOR("Jeremy Kerr <jk@codeconstruct.com.au>"); 709 710 MODULE_ALIAS_NETPROTO(PF_MCTP); 711