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 struct sk_msg *msg_rx; 19 int i, copied = 0; 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 copy = copy_page_to_iter(page, sge->offset, copy, iter); 41 if (!copy) 42 return copied ? copied : -EFAULT; 43 44 copied += copy; 45 if (likely(!peek)) { 46 sge->offset += copy; 47 sge->length -= copy; 48 if (!msg_rx->skb) 49 sk_mem_uncharge(sk, copy); 50 msg_rx->sg.size -= copy; 51 52 if (!sge->length) { 53 sk_msg_iter_var_next(i); 54 if (!msg_rx->skb) 55 put_page(page); 56 } 57 } else { 58 /* Lets not optimize peek case if copy_page_to_iter 59 * didn't copy the entire length lets just break. 60 */ 61 if (copy != sge->length) 62 return copied; 63 sk_msg_iter_var_next(i); 64 } 65 66 if (copied == len) 67 break; 68 } while (i != msg_rx->sg.end); 69 70 if (unlikely(peek)) { 71 if (msg_rx == list_last_entry(&psock->ingress_msg, 72 struct sk_msg, list)) 73 break; 74 msg_rx = list_next_entry(msg_rx, list); 75 continue; 76 } 77 78 msg_rx->sg.start = i; 79 if (!sge->length && msg_rx->sg.start == msg_rx->sg.end) { 80 list_del(&msg_rx->list); 81 if (msg_rx->skb) 82 consume_skb(msg_rx->skb); 83 kfree(msg_rx); 84 } 85 msg_rx = list_first_entry_or_null(&psock->ingress_msg, 86 struct sk_msg, list); 87 } 88 89 return copied; 90 } 91 EXPORT_SYMBOL_GPL(__tcp_bpf_recvmsg); 92 93 static int bpf_tcp_ingress(struct sock *sk, struct sk_psock *psock, 94 struct sk_msg *msg, u32 apply_bytes, int flags) 95 { 96 bool apply = apply_bytes; 97 struct scatterlist *sge; 98 u32 size, copied = 0; 99 struct sk_msg *tmp; 100 int i, ret = 0; 101 102 tmp = kzalloc(sizeof(*tmp), __GFP_NOWARN | GFP_KERNEL); 103 if (unlikely(!tmp)) 104 return -ENOMEM; 105 106 lock_sock(sk); 107 tmp->sg.start = msg->sg.start; 108 i = msg->sg.start; 109 do { 110 sge = sk_msg_elem(msg, i); 111 size = (apply && apply_bytes < sge->length) ? 112 apply_bytes : sge->length; 113 if (!sk_wmem_schedule(sk, size)) { 114 if (!copied) 115 ret = -ENOMEM; 116 break; 117 } 118 119 sk_mem_charge(sk, size); 120 sk_msg_xfer(tmp, msg, i, size); 121 copied += size; 122 if (sge->length) 123 get_page(sk_msg_page(tmp, i)); 124 sk_msg_iter_var_next(i); 125 tmp->sg.end = i; 126 if (apply) { 127 apply_bytes -= size; 128 if (!apply_bytes) 129 break; 130 } 131 } while (i != msg->sg.end); 132 133 if (!ret) { 134 msg->sg.start = i; 135 sk_psock_queue_msg(psock, tmp); 136 sk_psock_data_ready(sk, psock); 137 } else { 138 sk_msg_free(sk, tmp); 139 kfree(tmp); 140 } 141 142 release_sock(sk); 143 return ret; 144 } 145 146 static int tcp_bpf_push(struct sock *sk, struct sk_msg *msg, u32 apply_bytes, 147 int flags, bool uncharge) 148 { 149 bool apply = apply_bytes; 150 struct scatterlist *sge; 151 struct page *page; 152 int size, ret = 0; 153 u32 off; 154 155 while (1) { 156 bool has_tx_ulp; 157 158 sge = sk_msg_elem(msg, msg->sg.start); 159 size = (apply && apply_bytes < sge->length) ? 160 apply_bytes : sge->length; 161 off = sge->offset; 162 page = sg_page(sge); 163 164 tcp_rate_check_app_limited(sk); 165 retry: 166 has_tx_ulp = tls_sw_has_ctx_tx(sk); 167 if (has_tx_ulp) { 168 flags |= MSG_SENDPAGE_NOPOLICY; 169 ret = kernel_sendpage_locked(sk, 170 page, off, size, flags); 171 } else { 172 ret = do_tcp_sendpages(sk, page, off, size, flags); 173 } 174 175 if (ret <= 0) 176 return ret; 177 if (apply) 178 apply_bytes -= ret; 179 msg->sg.size -= ret; 180 sge->offset += ret; 181 sge->length -= ret; 182 if (uncharge) 183 sk_mem_uncharge(sk, ret); 184 if (ret != size) { 185 size -= ret; 186 off += ret; 187 goto retry; 188 } 189 if (!sge->length) { 190 put_page(page); 191 sk_msg_iter_next(msg, start); 192 sg_init_table(sge, 1); 193 if (msg->sg.start == msg->sg.end) 194 break; 195 } 196 if (apply && !apply_bytes) 197 break; 198 } 199 200 return 0; 201 } 202 203 static int tcp_bpf_push_locked(struct sock *sk, struct sk_msg *msg, 204 u32 apply_bytes, int flags, bool uncharge) 205 { 206 int ret; 207 208 lock_sock(sk); 209 ret = tcp_bpf_push(sk, msg, apply_bytes, flags, uncharge); 210 release_sock(sk); 211 return ret; 212 } 213 214 int tcp_bpf_sendmsg_redir(struct sock *sk, struct sk_msg *msg, 215 u32 bytes, int flags) 216 { 217 bool ingress = sk_msg_to_ingress(msg); 218 struct sk_psock *psock = sk_psock_get(sk); 219 int ret; 220 221 if (unlikely(!psock)) { 222 sk_msg_free(sk, msg); 223 return 0; 224 } 225 ret = ingress ? bpf_tcp_ingress(sk, psock, msg, bytes, flags) : 226 tcp_bpf_push_locked(sk, msg, bytes, flags, false); 227 sk_psock_put(sk, psock); 228 return ret; 229 } 230 EXPORT_SYMBOL_GPL(tcp_bpf_sendmsg_redir); 231 232 #ifdef CONFIG_BPF_STREAM_PARSER 233 static bool tcp_bpf_stream_read(const struct sock *sk) 234 { 235 struct sk_psock *psock; 236 bool empty = true; 237 238 rcu_read_lock(); 239 psock = sk_psock(sk); 240 if (likely(psock)) 241 empty = list_empty(&psock->ingress_msg); 242 rcu_read_unlock(); 243 return !empty; 244 } 245 246 static int tcp_bpf_wait_data(struct sock *sk, struct sk_psock *psock, 247 int flags, long timeo, int *err) 248 { 249 DEFINE_WAIT_FUNC(wait, woken_wake_function); 250 int ret = 0; 251 252 if (sk->sk_shutdown & RCV_SHUTDOWN) 253 return 1; 254 255 if (!timeo) 256 return ret; 257 258 add_wait_queue(sk_sleep(sk), &wait); 259 sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk); 260 ret = sk_wait_event(sk, &timeo, 261 !list_empty(&psock->ingress_msg) || 262 !skb_queue_empty(&sk->sk_receive_queue), &wait); 263 sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk); 264 remove_wait_queue(sk_sleep(sk), &wait); 265 return ret; 266 } 267 268 static int tcp_bpf_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, 269 int nonblock, int flags, int *addr_len) 270 { 271 struct sk_psock *psock; 272 int copied, ret; 273 274 if (unlikely(flags & MSG_ERRQUEUE)) 275 return inet_recv_error(sk, msg, len, addr_len); 276 277 psock = sk_psock_get(sk); 278 if (unlikely(!psock)) 279 return tcp_recvmsg(sk, msg, len, nonblock, flags, addr_len); 280 if (!skb_queue_empty(&sk->sk_receive_queue) && 281 sk_psock_queue_empty(psock)) { 282 sk_psock_put(sk, psock); 283 return tcp_recvmsg(sk, msg, len, nonblock, flags, addr_len); 284 } 285 lock_sock(sk); 286 msg_bytes_ready: 287 copied = __tcp_bpf_recvmsg(sk, psock, msg, len, flags); 288 if (!copied) { 289 int data, err = 0; 290 long timeo; 291 292 timeo = sock_rcvtimeo(sk, nonblock); 293 data = tcp_bpf_wait_data(sk, psock, flags, timeo, &err); 294 if (data) { 295 if (!sk_psock_queue_empty(psock)) 296 goto msg_bytes_ready; 297 release_sock(sk); 298 sk_psock_put(sk, psock); 299 return tcp_recvmsg(sk, msg, len, nonblock, flags, addr_len); 300 } 301 if (err) { 302 ret = err; 303 goto out; 304 } 305 copied = -EAGAIN; 306 } 307 ret = copied; 308 out: 309 release_sock(sk); 310 sk_psock_put(sk, psock); 311 return ret; 312 } 313 314 static int tcp_bpf_send_verdict(struct sock *sk, struct sk_psock *psock, 315 struct sk_msg *msg, int *copied, int flags) 316 { 317 bool cork = false, enospc = sk_msg_full(msg); 318 struct sock *sk_redir; 319 u32 tosend, delta = 0; 320 int ret; 321 322 more_data: 323 if (psock->eval == __SK_NONE) { 324 /* Track delta in msg size to add/subtract it on SK_DROP from 325 * returned to user copied size. This ensures user doesn't 326 * get a positive return code with msg_cut_data and SK_DROP 327 * verdict. 328 */ 329 delta = msg->sg.size; 330 psock->eval = sk_psock_msg_verdict(sk, psock, msg); 331 delta -= msg->sg.size; 332 } 333 334 if (msg->cork_bytes && 335 msg->cork_bytes > msg->sg.size && !enospc) { 336 psock->cork_bytes = msg->cork_bytes - msg->sg.size; 337 if (!psock->cork) { 338 psock->cork = kzalloc(sizeof(*psock->cork), 339 GFP_ATOMIC | __GFP_NOWARN); 340 if (!psock->cork) 341 return -ENOMEM; 342 } 343 memcpy(psock->cork, msg, sizeof(*msg)); 344 return 0; 345 } 346 347 tosend = msg->sg.size; 348 if (psock->apply_bytes && psock->apply_bytes < tosend) 349 tosend = psock->apply_bytes; 350 351 switch (psock->eval) { 352 case __SK_PASS: 353 ret = tcp_bpf_push(sk, msg, tosend, flags, true); 354 if (unlikely(ret)) { 355 *copied -= sk_msg_free(sk, msg); 356 break; 357 } 358 sk_msg_apply_bytes(psock, tosend); 359 break; 360 case __SK_REDIRECT: 361 sk_redir = psock->sk_redir; 362 sk_msg_apply_bytes(psock, tosend); 363 if (psock->cork) { 364 cork = true; 365 psock->cork = NULL; 366 } 367 sk_msg_return(sk, msg, tosend); 368 release_sock(sk); 369 ret = tcp_bpf_sendmsg_redir(sk_redir, msg, tosend, flags); 370 lock_sock(sk); 371 if (unlikely(ret < 0)) { 372 int free = sk_msg_free_nocharge(sk, msg); 373 374 if (!cork) 375 *copied -= free; 376 } 377 if (cork) { 378 sk_msg_free(sk, msg); 379 kfree(msg); 380 msg = NULL; 381 ret = 0; 382 } 383 break; 384 case __SK_DROP: 385 default: 386 sk_msg_free_partial(sk, msg, tosend); 387 sk_msg_apply_bytes(psock, tosend); 388 *copied -= (tosend + delta); 389 return -EACCES; 390 } 391 392 if (likely(!ret)) { 393 if (!psock->apply_bytes) { 394 psock->eval = __SK_NONE; 395 if (psock->sk_redir) { 396 sock_put(psock->sk_redir); 397 psock->sk_redir = NULL; 398 } 399 } 400 if (msg && 401 msg->sg.data[msg->sg.start].page_link && 402 msg->sg.data[msg->sg.start].length) 403 goto more_data; 404 } 405 return ret; 406 } 407 408 static int tcp_bpf_sendmsg(struct sock *sk, struct msghdr *msg, size_t size) 409 { 410 struct sk_msg tmp, *msg_tx = NULL; 411 int copied = 0, err = 0; 412 struct sk_psock *psock; 413 long timeo; 414 int flags; 415 416 /* Don't let internal do_tcp_sendpages() flags through */ 417 flags = (msg->msg_flags & ~MSG_SENDPAGE_DECRYPTED); 418 flags |= MSG_NO_SHARED_FRAGS; 419 420 psock = sk_psock_get(sk); 421 if (unlikely(!psock)) 422 return tcp_sendmsg(sk, msg, size); 423 424 lock_sock(sk); 425 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT); 426 while (msg_data_left(msg)) { 427 bool enospc = false; 428 u32 copy, osize; 429 430 if (sk->sk_err) { 431 err = -sk->sk_err; 432 goto out_err; 433 } 434 435 copy = msg_data_left(msg); 436 if (!sk_stream_memory_free(sk)) 437 goto wait_for_sndbuf; 438 if (psock->cork) { 439 msg_tx = psock->cork; 440 } else { 441 msg_tx = &tmp; 442 sk_msg_init(msg_tx); 443 } 444 445 osize = msg_tx->sg.size; 446 err = sk_msg_alloc(sk, msg_tx, msg_tx->sg.size + copy, msg_tx->sg.end - 1); 447 if (err) { 448 if (err != -ENOSPC) 449 goto wait_for_memory; 450 enospc = true; 451 copy = msg_tx->sg.size - osize; 452 } 453 454 err = sk_msg_memcopy_from_iter(sk, &msg->msg_iter, msg_tx, 455 copy); 456 if (err < 0) { 457 sk_msg_trim(sk, msg_tx, osize); 458 goto out_err; 459 } 460 461 copied += copy; 462 if (psock->cork_bytes) { 463 if (size > psock->cork_bytes) 464 psock->cork_bytes = 0; 465 else 466 psock->cork_bytes -= size; 467 if (psock->cork_bytes && !enospc) 468 goto out_err; 469 /* All cork bytes are accounted, rerun the prog. */ 470 psock->eval = __SK_NONE; 471 psock->cork_bytes = 0; 472 } 473 474 err = tcp_bpf_send_verdict(sk, psock, msg_tx, &copied, flags); 475 if (unlikely(err < 0)) 476 goto out_err; 477 continue; 478 wait_for_sndbuf: 479 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 480 wait_for_memory: 481 err = sk_stream_wait_memory(sk, &timeo); 482 if (err) { 483 if (msg_tx && msg_tx != psock->cork) 484 sk_msg_free(sk, msg_tx); 485 goto out_err; 486 } 487 } 488 out_err: 489 if (err < 0) 490 err = sk_stream_error(sk, msg->msg_flags, err); 491 release_sock(sk); 492 sk_psock_put(sk, psock); 493 return copied ? copied : err; 494 } 495 496 static int tcp_bpf_sendpage(struct sock *sk, struct page *page, int offset, 497 size_t size, int flags) 498 { 499 struct sk_msg tmp, *msg = NULL; 500 int err = 0, copied = 0; 501 struct sk_psock *psock; 502 bool enospc = false; 503 504 psock = sk_psock_get(sk); 505 if (unlikely(!psock)) 506 return tcp_sendpage(sk, page, offset, size, flags); 507 508 lock_sock(sk); 509 if (psock->cork) { 510 msg = psock->cork; 511 } else { 512 msg = &tmp; 513 sk_msg_init(msg); 514 } 515 516 /* Catch case where ring is full and sendpage is stalled. */ 517 if (unlikely(sk_msg_full(msg))) 518 goto out_err; 519 520 sk_msg_page_add(msg, page, size, offset); 521 sk_mem_charge(sk, size); 522 copied = size; 523 if (sk_msg_full(msg)) 524 enospc = true; 525 if (psock->cork_bytes) { 526 if (size > psock->cork_bytes) 527 psock->cork_bytes = 0; 528 else 529 psock->cork_bytes -= size; 530 if (psock->cork_bytes && !enospc) 531 goto out_err; 532 /* All cork bytes are accounted, rerun the prog. */ 533 psock->eval = __SK_NONE; 534 psock->cork_bytes = 0; 535 } 536 537 err = tcp_bpf_send_verdict(sk, psock, msg, &copied, flags); 538 out_err: 539 release_sock(sk); 540 sk_psock_put(sk, psock); 541 return copied ? copied : err; 542 } 543 544 enum { 545 TCP_BPF_IPV4, 546 TCP_BPF_IPV6, 547 TCP_BPF_NUM_PROTS, 548 }; 549 550 enum { 551 TCP_BPF_BASE, 552 TCP_BPF_TX, 553 TCP_BPF_NUM_CFGS, 554 }; 555 556 static struct proto *tcpv6_prot_saved __read_mostly; 557 static DEFINE_SPINLOCK(tcpv6_prot_lock); 558 static struct proto tcp_bpf_prots[TCP_BPF_NUM_PROTS][TCP_BPF_NUM_CFGS]; 559 560 static void tcp_bpf_rebuild_protos(struct proto prot[TCP_BPF_NUM_CFGS], 561 struct proto *base) 562 { 563 prot[TCP_BPF_BASE] = *base; 564 prot[TCP_BPF_BASE].unhash = sock_map_unhash; 565 prot[TCP_BPF_BASE].close = sock_map_close; 566 prot[TCP_BPF_BASE].recvmsg = tcp_bpf_recvmsg; 567 prot[TCP_BPF_BASE].stream_memory_read = tcp_bpf_stream_read; 568 569 prot[TCP_BPF_TX] = prot[TCP_BPF_BASE]; 570 prot[TCP_BPF_TX].sendmsg = tcp_bpf_sendmsg; 571 prot[TCP_BPF_TX].sendpage = tcp_bpf_sendpage; 572 } 573 574 static void tcp_bpf_check_v6_needs_rebuild(struct proto *ops) 575 { 576 if (unlikely(ops != smp_load_acquire(&tcpv6_prot_saved))) { 577 spin_lock_bh(&tcpv6_prot_lock); 578 if (likely(ops != tcpv6_prot_saved)) { 579 tcp_bpf_rebuild_protos(tcp_bpf_prots[TCP_BPF_IPV6], ops); 580 smp_store_release(&tcpv6_prot_saved, ops); 581 } 582 spin_unlock_bh(&tcpv6_prot_lock); 583 } 584 } 585 586 static int __init tcp_bpf_v4_build_proto(void) 587 { 588 tcp_bpf_rebuild_protos(tcp_bpf_prots[TCP_BPF_IPV4], &tcp_prot); 589 return 0; 590 } 591 core_initcall(tcp_bpf_v4_build_proto); 592 593 static int tcp_bpf_assert_proto_ops(struct proto *ops) 594 { 595 /* In order to avoid retpoline, we make assumptions when we call 596 * into ops if e.g. a psock is not present. Make sure they are 597 * indeed valid assumptions. 598 */ 599 return ops->recvmsg == tcp_recvmsg && 600 ops->sendmsg == tcp_sendmsg && 601 ops->sendpage == tcp_sendpage ? 0 : -ENOTSUPP; 602 } 603 604 struct proto *tcp_bpf_get_proto(struct sock *sk, struct sk_psock *psock) 605 { 606 int family = sk->sk_family == AF_INET6 ? TCP_BPF_IPV6 : TCP_BPF_IPV4; 607 int config = psock->progs.msg_parser ? TCP_BPF_TX : TCP_BPF_BASE; 608 609 if (sk->sk_family == AF_INET6) { 610 if (tcp_bpf_assert_proto_ops(psock->sk_proto)) 611 return ERR_PTR(-EINVAL); 612 613 tcp_bpf_check_v6_needs_rebuild(psock->sk_proto); 614 } 615 616 return &tcp_bpf_prots[family][config]; 617 } 618 619 /* If a child got cloned from a listening socket that had tcp_bpf 620 * protocol callbacks installed, we need to restore the callbacks to 621 * the default ones because the child does not inherit the psock state 622 * that tcp_bpf callbacks expect. 623 */ 624 void tcp_bpf_clone(const struct sock *sk, struct sock *newsk) 625 { 626 int family = sk->sk_family == AF_INET6 ? TCP_BPF_IPV6 : TCP_BPF_IPV4; 627 struct proto *prot = newsk->sk_prot; 628 629 if (prot == &tcp_bpf_prots[family][TCP_BPF_BASE]) 630 newsk->sk_prot = sk->sk_prot_creator; 631 } 632 #endif /* CONFIG_BPF_STREAM_PARSER */ 633