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