1 // SPDX-License-Identifier: GPL-2.0 2 /* Copyright (c) 2017 - 2018 Covalent IO, Inc. http://covalent.io */ 3 4 #include <linux/skmsg.h> 5 #include <linux/filter.h> 6 #include <linux/bpf.h> 7 #include <linux/init.h> 8 #include <linux/wait.h> 9 10 #include <net/inet_common.h> 11 #include <net/tls.h> 12 13 int __tcp_bpf_recvmsg(struct sock *sk, struct sk_psock *psock, 14 struct msghdr *msg, int len, int flags) 15 { 16 struct iov_iter *iter = &msg->msg_iter; 17 int peek = flags & MSG_PEEK; 18 int i, ret, copied = 0; 19 struct sk_msg *msg_rx; 20 21 msg_rx = list_first_entry_or_null(&psock->ingress_msg, 22 struct sk_msg, list); 23 24 while (copied != len) { 25 struct scatterlist *sge; 26 27 if (unlikely(!msg_rx)) 28 break; 29 30 i = msg_rx->sg.start; 31 do { 32 struct page *page; 33 int copy; 34 35 sge = sk_msg_elem(msg_rx, i); 36 copy = sge->length; 37 page = sg_page(sge); 38 if (copied + copy > len) 39 copy = len - copied; 40 ret = copy_page_to_iter(page, sge->offset, copy, iter); 41 if (ret != copy) { 42 msg_rx->sg.start = i; 43 return -EFAULT; 44 } 45 46 copied += copy; 47 if (likely(!peek)) { 48 sge->offset += copy; 49 sge->length -= copy; 50 sk_mem_uncharge(sk, copy); 51 msg_rx->sg.size -= copy; 52 53 if (!sge->length) { 54 sk_msg_iter_var_next(i); 55 if (!msg_rx->skb) 56 put_page(page); 57 } 58 } else { 59 sk_msg_iter_var_next(i); 60 } 61 62 if (copied == len) 63 break; 64 } while (i != msg_rx->sg.end); 65 66 if (unlikely(peek)) { 67 if (msg_rx == list_last_entry(&psock->ingress_msg, 68 struct sk_msg, list)) 69 break; 70 msg_rx = list_next_entry(msg_rx, list); 71 continue; 72 } 73 74 msg_rx->sg.start = i; 75 if (!sge->length && msg_rx->sg.start == msg_rx->sg.end) { 76 list_del(&msg_rx->list); 77 if (msg_rx->skb) 78 consume_skb(msg_rx->skb); 79 kfree(msg_rx); 80 } 81 msg_rx = list_first_entry_or_null(&psock->ingress_msg, 82 struct sk_msg, list); 83 } 84 85 return copied; 86 } 87 EXPORT_SYMBOL_GPL(__tcp_bpf_recvmsg); 88 89 static int bpf_tcp_ingress(struct sock *sk, struct sk_psock *psock, 90 struct sk_msg *msg, u32 apply_bytes, int flags) 91 { 92 bool apply = apply_bytes; 93 struct scatterlist *sge; 94 u32 size, copied = 0; 95 struct sk_msg *tmp; 96 int i, ret = 0; 97 98 tmp = kzalloc(sizeof(*tmp), __GFP_NOWARN | GFP_KERNEL); 99 if (unlikely(!tmp)) 100 return -ENOMEM; 101 102 lock_sock(sk); 103 tmp->sg.start = msg->sg.start; 104 i = msg->sg.start; 105 do { 106 sge = sk_msg_elem(msg, i); 107 size = (apply && apply_bytes < sge->length) ? 108 apply_bytes : sge->length; 109 if (!sk_wmem_schedule(sk, size)) { 110 if (!copied) 111 ret = -ENOMEM; 112 break; 113 } 114 115 sk_mem_charge(sk, size); 116 sk_msg_xfer(tmp, msg, i, size); 117 copied += size; 118 if (sge->length) 119 get_page(sk_msg_page(tmp, i)); 120 sk_msg_iter_var_next(i); 121 tmp->sg.end = i; 122 if (apply) { 123 apply_bytes -= size; 124 if (!apply_bytes) 125 break; 126 } 127 } while (i != msg->sg.end); 128 129 if (!ret) { 130 msg->sg.start = i; 131 sk_psock_queue_msg(psock, tmp); 132 sk_psock_data_ready(sk, psock); 133 } else { 134 sk_msg_free(sk, tmp); 135 kfree(tmp); 136 } 137 138 release_sock(sk); 139 return ret; 140 } 141 142 static int tcp_bpf_push(struct sock *sk, struct sk_msg *msg, u32 apply_bytes, 143 int flags, bool uncharge) 144 { 145 bool apply = apply_bytes; 146 struct scatterlist *sge; 147 struct page *page; 148 int size, ret = 0; 149 u32 off; 150 151 while (1) { 152 bool has_tx_ulp; 153 154 sge = sk_msg_elem(msg, msg->sg.start); 155 size = (apply && apply_bytes < sge->length) ? 156 apply_bytes : sge->length; 157 off = sge->offset; 158 page = sg_page(sge); 159 160 tcp_rate_check_app_limited(sk); 161 retry: 162 has_tx_ulp = tls_sw_has_ctx_tx(sk); 163 if (has_tx_ulp) { 164 flags |= MSG_SENDPAGE_NOPOLICY; 165 ret = kernel_sendpage_locked(sk, 166 page, off, size, flags); 167 } else { 168 ret = do_tcp_sendpages(sk, page, off, size, flags); 169 } 170 171 if (ret <= 0) 172 return ret; 173 if (apply) 174 apply_bytes -= ret; 175 msg->sg.size -= ret; 176 sge->offset += ret; 177 sge->length -= ret; 178 if (uncharge) 179 sk_mem_uncharge(sk, ret); 180 if (ret != size) { 181 size -= ret; 182 off += ret; 183 goto retry; 184 } 185 if (!sge->length) { 186 put_page(page); 187 sk_msg_iter_next(msg, start); 188 sg_init_table(sge, 1); 189 if (msg->sg.start == msg->sg.end) 190 break; 191 } 192 if (apply && !apply_bytes) 193 break; 194 } 195 196 return 0; 197 } 198 199 static int tcp_bpf_push_locked(struct sock *sk, struct sk_msg *msg, 200 u32 apply_bytes, int flags, bool uncharge) 201 { 202 int ret; 203 204 lock_sock(sk); 205 ret = tcp_bpf_push(sk, msg, apply_bytes, flags, uncharge); 206 release_sock(sk); 207 return ret; 208 } 209 210 int tcp_bpf_sendmsg_redir(struct sock *sk, struct sk_msg *msg, 211 u32 bytes, int flags) 212 { 213 bool ingress = sk_msg_to_ingress(msg); 214 struct sk_psock *psock = sk_psock_get(sk); 215 int ret; 216 217 if (unlikely(!psock)) { 218 sk_msg_free(sk, msg); 219 return 0; 220 } 221 ret = ingress ? bpf_tcp_ingress(sk, psock, msg, bytes, flags) : 222 tcp_bpf_push_locked(sk, msg, bytes, flags, false); 223 sk_psock_put(sk, psock); 224 return ret; 225 } 226 EXPORT_SYMBOL_GPL(tcp_bpf_sendmsg_redir); 227 228 #ifdef CONFIG_BPF_STREAM_PARSER 229 static bool tcp_bpf_stream_read(const struct sock *sk) 230 { 231 struct sk_psock *psock; 232 bool empty = true; 233 234 rcu_read_lock(); 235 psock = sk_psock(sk); 236 if (likely(psock)) 237 empty = list_empty(&psock->ingress_msg); 238 rcu_read_unlock(); 239 return !empty; 240 } 241 242 static int tcp_bpf_wait_data(struct sock *sk, struct sk_psock *psock, 243 int flags, long timeo, int *err) 244 { 245 DEFINE_WAIT_FUNC(wait, woken_wake_function); 246 int ret = 0; 247 248 if (sk->sk_shutdown & RCV_SHUTDOWN) 249 return 1; 250 251 if (!timeo) 252 return ret; 253 254 add_wait_queue(sk_sleep(sk), &wait); 255 sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk); 256 ret = sk_wait_event(sk, &timeo, 257 !list_empty(&psock->ingress_msg) || 258 !skb_queue_empty(&sk->sk_receive_queue), &wait); 259 sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk); 260 remove_wait_queue(sk_sleep(sk), &wait); 261 return ret; 262 } 263 264 static int tcp_bpf_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, 265 int nonblock, int flags, int *addr_len) 266 { 267 struct sk_psock *psock; 268 int copied, ret; 269 270 if (unlikely(flags & MSG_ERRQUEUE)) 271 return inet_recv_error(sk, msg, len, addr_len); 272 273 psock = sk_psock_get(sk); 274 if (unlikely(!psock)) 275 return tcp_recvmsg(sk, msg, len, nonblock, flags, addr_len); 276 if (!skb_queue_empty(&sk->sk_receive_queue) && 277 sk_psock_queue_empty(psock)) { 278 sk_psock_put(sk, psock); 279 return tcp_recvmsg(sk, msg, len, nonblock, flags, addr_len); 280 } 281 lock_sock(sk); 282 msg_bytes_ready: 283 copied = __tcp_bpf_recvmsg(sk, psock, msg, len, flags); 284 if (!copied) { 285 int data, err = 0; 286 long timeo; 287 288 timeo = sock_rcvtimeo(sk, nonblock); 289 data = tcp_bpf_wait_data(sk, psock, flags, timeo, &err); 290 if (data) { 291 if (!sk_psock_queue_empty(psock)) 292 goto msg_bytes_ready; 293 release_sock(sk); 294 sk_psock_put(sk, psock); 295 return tcp_recvmsg(sk, msg, len, nonblock, flags, addr_len); 296 } 297 if (err) { 298 ret = err; 299 goto out; 300 } 301 copied = -EAGAIN; 302 } 303 ret = copied; 304 out: 305 release_sock(sk); 306 sk_psock_put(sk, psock); 307 return ret; 308 } 309 310 static int tcp_bpf_send_verdict(struct sock *sk, struct sk_psock *psock, 311 struct sk_msg *msg, int *copied, int flags) 312 { 313 bool cork = false, enospc = sk_msg_full(msg); 314 struct sock *sk_redir; 315 u32 tosend, delta = 0; 316 int ret; 317 318 more_data: 319 if (psock->eval == __SK_NONE) { 320 /* Track delta in msg size to add/subtract it on SK_DROP from 321 * returned to user copied size. This ensures user doesn't 322 * get a positive return code with msg_cut_data and SK_DROP 323 * verdict. 324 */ 325 delta = msg->sg.size; 326 psock->eval = sk_psock_msg_verdict(sk, psock, msg); 327 delta -= msg->sg.size; 328 } 329 330 if (msg->cork_bytes && 331 msg->cork_bytes > msg->sg.size && !enospc) { 332 psock->cork_bytes = msg->cork_bytes - msg->sg.size; 333 if (!psock->cork) { 334 psock->cork = kzalloc(sizeof(*psock->cork), 335 GFP_ATOMIC | __GFP_NOWARN); 336 if (!psock->cork) 337 return -ENOMEM; 338 } 339 memcpy(psock->cork, msg, sizeof(*msg)); 340 return 0; 341 } 342 343 tosend = msg->sg.size; 344 if (psock->apply_bytes && psock->apply_bytes < tosend) 345 tosend = psock->apply_bytes; 346 347 switch (psock->eval) { 348 case __SK_PASS: 349 ret = tcp_bpf_push(sk, msg, tosend, flags, true); 350 if (unlikely(ret)) { 351 *copied -= sk_msg_free(sk, msg); 352 break; 353 } 354 sk_msg_apply_bytes(psock, tosend); 355 break; 356 case __SK_REDIRECT: 357 sk_redir = psock->sk_redir; 358 sk_msg_apply_bytes(psock, tosend); 359 if (psock->cork) { 360 cork = true; 361 psock->cork = NULL; 362 } 363 sk_msg_return(sk, msg, tosend); 364 release_sock(sk); 365 ret = tcp_bpf_sendmsg_redir(sk_redir, msg, tosend, flags); 366 lock_sock(sk); 367 if (unlikely(ret < 0)) { 368 int free = sk_msg_free_nocharge(sk, msg); 369 370 if (!cork) 371 *copied -= free; 372 } 373 if (cork) { 374 sk_msg_free(sk, msg); 375 kfree(msg); 376 msg = NULL; 377 ret = 0; 378 } 379 break; 380 case __SK_DROP: 381 default: 382 sk_msg_free_partial(sk, msg, tosend); 383 sk_msg_apply_bytes(psock, tosend); 384 *copied -= (tosend + delta); 385 return -EACCES; 386 } 387 388 if (likely(!ret)) { 389 if (!psock->apply_bytes) { 390 psock->eval = __SK_NONE; 391 if (psock->sk_redir) { 392 sock_put(psock->sk_redir); 393 psock->sk_redir = NULL; 394 } 395 } 396 if (msg && 397 msg->sg.data[msg->sg.start].page_link && 398 msg->sg.data[msg->sg.start].length) 399 goto more_data; 400 } 401 return ret; 402 } 403 404 static int tcp_bpf_sendmsg(struct sock *sk, struct msghdr *msg, size_t size) 405 { 406 struct sk_msg tmp, *msg_tx = NULL; 407 int copied = 0, err = 0; 408 struct sk_psock *psock; 409 long timeo; 410 int flags; 411 412 /* Don't let internal do_tcp_sendpages() flags through */ 413 flags = (msg->msg_flags & ~MSG_SENDPAGE_DECRYPTED); 414 flags |= MSG_NO_SHARED_FRAGS; 415 416 psock = sk_psock_get(sk); 417 if (unlikely(!psock)) 418 return tcp_sendmsg(sk, msg, size); 419 420 lock_sock(sk); 421 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT); 422 while (msg_data_left(msg)) { 423 bool enospc = false; 424 u32 copy, osize; 425 426 if (sk->sk_err) { 427 err = -sk->sk_err; 428 goto out_err; 429 } 430 431 copy = msg_data_left(msg); 432 if (!sk_stream_memory_free(sk)) 433 goto wait_for_sndbuf; 434 if (psock->cork) { 435 msg_tx = psock->cork; 436 } else { 437 msg_tx = &tmp; 438 sk_msg_init(msg_tx); 439 } 440 441 osize = msg_tx->sg.size; 442 err = sk_msg_alloc(sk, msg_tx, msg_tx->sg.size + copy, msg_tx->sg.end - 1); 443 if (err) { 444 if (err != -ENOSPC) 445 goto wait_for_memory; 446 enospc = true; 447 copy = msg_tx->sg.size - osize; 448 } 449 450 err = sk_msg_memcopy_from_iter(sk, &msg->msg_iter, msg_tx, 451 copy); 452 if (err < 0) { 453 sk_msg_trim(sk, msg_tx, osize); 454 goto out_err; 455 } 456 457 copied += copy; 458 if (psock->cork_bytes) { 459 if (size > psock->cork_bytes) 460 psock->cork_bytes = 0; 461 else 462 psock->cork_bytes -= size; 463 if (psock->cork_bytes && !enospc) 464 goto out_err; 465 /* All cork bytes are accounted, rerun the prog. */ 466 psock->eval = __SK_NONE; 467 psock->cork_bytes = 0; 468 } 469 470 err = tcp_bpf_send_verdict(sk, psock, msg_tx, &copied, flags); 471 if (unlikely(err < 0)) 472 goto out_err; 473 continue; 474 wait_for_sndbuf: 475 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 476 wait_for_memory: 477 err = sk_stream_wait_memory(sk, &timeo); 478 if (err) { 479 if (msg_tx && msg_tx != psock->cork) 480 sk_msg_free(sk, msg_tx); 481 goto out_err; 482 } 483 } 484 out_err: 485 if (err < 0) 486 err = sk_stream_error(sk, msg->msg_flags, err); 487 release_sock(sk); 488 sk_psock_put(sk, psock); 489 return copied ? copied : err; 490 } 491 492 static int tcp_bpf_sendpage(struct sock *sk, struct page *page, int offset, 493 size_t size, int flags) 494 { 495 struct sk_msg tmp, *msg = NULL; 496 int err = 0, copied = 0; 497 struct sk_psock *psock; 498 bool enospc = false; 499 500 psock = sk_psock_get(sk); 501 if (unlikely(!psock)) 502 return tcp_sendpage(sk, page, offset, size, flags); 503 504 lock_sock(sk); 505 if (psock->cork) { 506 msg = psock->cork; 507 } else { 508 msg = &tmp; 509 sk_msg_init(msg); 510 } 511 512 /* Catch case where ring is full and sendpage is stalled. */ 513 if (unlikely(sk_msg_full(msg))) 514 goto out_err; 515 516 sk_msg_page_add(msg, page, size, offset); 517 sk_mem_charge(sk, size); 518 copied = size; 519 if (sk_msg_full(msg)) 520 enospc = true; 521 if (psock->cork_bytes) { 522 if (size > psock->cork_bytes) 523 psock->cork_bytes = 0; 524 else 525 psock->cork_bytes -= size; 526 if (psock->cork_bytes && !enospc) 527 goto out_err; 528 /* All cork bytes are accounted, rerun the prog. */ 529 psock->eval = __SK_NONE; 530 psock->cork_bytes = 0; 531 } 532 533 err = tcp_bpf_send_verdict(sk, psock, msg, &copied, flags); 534 out_err: 535 release_sock(sk); 536 sk_psock_put(sk, psock); 537 return copied ? copied : err; 538 } 539 540 enum { 541 TCP_BPF_IPV4, 542 TCP_BPF_IPV6, 543 TCP_BPF_NUM_PROTS, 544 }; 545 546 enum { 547 TCP_BPF_BASE, 548 TCP_BPF_TX, 549 TCP_BPF_NUM_CFGS, 550 }; 551 552 static struct proto *tcpv6_prot_saved __read_mostly; 553 static DEFINE_SPINLOCK(tcpv6_prot_lock); 554 static struct proto tcp_bpf_prots[TCP_BPF_NUM_PROTS][TCP_BPF_NUM_CFGS]; 555 556 static void tcp_bpf_rebuild_protos(struct proto prot[TCP_BPF_NUM_CFGS], 557 struct proto *base) 558 { 559 prot[TCP_BPF_BASE] = *base; 560 prot[TCP_BPF_BASE].unhash = sock_map_unhash; 561 prot[TCP_BPF_BASE].close = sock_map_close; 562 prot[TCP_BPF_BASE].recvmsg = tcp_bpf_recvmsg; 563 prot[TCP_BPF_BASE].stream_memory_read = tcp_bpf_stream_read; 564 565 prot[TCP_BPF_TX] = prot[TCP_BPF_BASE]; 566 prot[TCP_BPF_TX].sendmsg = tcp_bpf_sendmsg; 567 prot[TCP_BPF_TX].sendpage = tcp_bpf_sendpage; 568 } 569 570 static void tcp_bpf_check_v6_needs_rebuild(struct sock *sk, struct proto *ops) 571 { 572 if (sk->sk_family == AF_INET6 && 573 unlikely(ops != smp_load_acquire(&tcpv6_prot_saved))) { 574 spin_lock_bh(&tcpv6_prot_lock); 575 if (likely(ops != tcpv6_prot_saved)) { 576 tcp_bpf_rebuild_protos(tcp_bpf_prots[TCP_BPF_IPV6], ops); 577 smp_store_release(&tcpv6_prot_saved, ops); 578 } 579 spin_unlock_bh(&tcpv6_prot_lock); 580 } 581 } 582 583 static int __init tcp_bpf_v4_build_proto(void) 584 { 585 tcp_bpf_rebuild_protos(tcp_bpf_prots[TCP_BPF_IPV4], &tcp_prot); 586 return 0; 587 } 588 core_initcall(tcp_bpf_v4_build_proto); 589 590 static int tcp_bpf_assert_proto_ops(struct proto *ops) 591 { 592 /* In order to avoid retpoline, we make assumptions when we call 593 * into ops if e.g. a psock is not present. Make sure they are 594 * indeed valid assumptions. 595 */ 596 return ops->recvmsg == tcp_recvmsg && 597 ops->sendmsg == tcp_sendmsg && 598 ops->sendpage == tcp_sendpage ? 0 : -ENOTSUPP; 599 } 600 601 struct proto *tcp_bpf_get_proto(struct sock *sk, struct sk_psock *psock) 602 { 603 int family = sk->sk_family == AF_INET6 ? TCP_BPF_IPV6 : TCP_BPF_IPV4; 604 int config = psock->progs.msg_parser ? TCP_BPF_TX : TCP_BPF_BASE; 605 606 if (!psock->sk_proto) { 607 struct proto *ops = READ_ONCE(sk->sk_prot); 608 609 if (tcp_bpf_assert_proto_ops(ops)) 610 return ERR_PTR(-EINVAL); 611 612 tcp_bpf_check_v6_needs_rebuild(sk, ops); 613 } 614 615 return &tcp_bpf_prots[family][config]; 616 } 617 618 /* If a child got cloned from a listening socket that had tcp_bpf 619 * protocol callbacks installed, we need to restore the callbacks to 620 * the default ones because the child does not inherit the psock state 621 * that tcp_bpf callbacks expect. 622 */ 623 void tcp_bpf_clone(const struct sock *sk, struct sock *newsk) 624 { 625 int family = sk->sk_family == AF_INET6 ? TCP_BPF_IPV6 : TCP_BPF_IPV4; 626 struct proto *prot = newsk->sk_prot; 627 628 if (prot == &tcp_bpf_prots[family][TCP_BPF_BASE]) 629 newsk->sk_prot = sk->sk_prot_creator; 630 } 631 #endif /* CONFIG_BPF_STREAM_PARSER */ 632