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 static int bpf_tcp_ingress(struct sock *sk, struct sk_psock *psock, 14 struct sk_msg *msg, u32 apply_bytes, int flags) 15 { 16 bool apply = apply_bytes; 17 struct scatterlist *sge; 18 u32 size, copied = 0; 19 struct sk_msg *tmp; 20 int i, ret = 0; 21 22 tmp = kzalloc(sizeof(*tmp), __GFP_NOWARN | GFP_KERNEL); 23 if (unlikely(!tmp)) 24 return -ENOMEM; 25 26 lock_sock(sk); 27 tmp->sg.start = msg->sg.start; 28 i = msg->sg.start; 29 do { 30 sge = sk_msg_elem(msg, i); 31 size = (apply && apply_bytes < sge->length) ? 32 apply_bytes : sge->length; 33 if (!sk_wmem_schedule(sk, size)) { 34 if (!copied) 35 ret = -ENOMEM; 36 break; 37 } 38 39 sk_mem_charge(sk, size); 40 sk_msg_xfer(tmp, msg, i, size); 41 copied += size; 42 if (sge->length) 43 get_page(sk_msg_page(tmp, i)); 44 sk_msg_iter_var_next(i); 45 tmp->sg.end = i; 46 if (apply) { 47 apply_bytes -= size; 48 if (!apply_bytes) 49 break; 50 } 51 } while (i != msg->sg.end); 52 53 if (!ret) { 54 msg->sg.start = i; 55 sk_psock_queue_msg(psock, tmp); 56 sk_psock_data_ready(sk, psock); 57 } else { 58 sk_msg_free(sk, tmp); 59 kfree(tmp); 60 } 61 62 release_sock(sk); 63 return ret; 64 } 65 66 static int tcp_bpf_push(struct sock *sk, struct sk_msg *msg, u32 apply_bytes, 67 int flags, bool uncharge) 68 { 69 bool apply = apply_bytes; 70 struct scatterlist *sge; 71 struct page *page; 72 int size, ret = 0; 73 u32 off; 74 75 while (1) { 76 bool has_tx_ulp; 77 78 sge = sk_msg_elem(msg, msg->sg.start); 79 size = (apply && apply_bytes < sge->length) ? 80 apply_bytes : sge->length; 81 off = sge->offset; 82 page = sg_page(sge); 83 84 tcp_rate_check_app_limited(sk); 85 retry: 86 has_tx_ulp = tls_sw_has_ctx_tx(sk); 87 if (has_tx_ulp) { 88 flags |= MSG_SENDPAGE_NOPOLICY; 89 ret = kernel_sendpage_locked(sk, 90 page, off, size, flags); 91 } else { 92 ret = do_tcp_sendpages(sk, page, off, size, flags); 93 } 94 95 if (ret <= 0) 96 return ret; 97 if (apply) 98 apply_bytes -= ret; 99 msg->sg.size -= ret; 100 sge->offset += ret; 101 sge->length -= ret; 102 if (uncharge) 103 sk_mem_uncharge(sk, ret); 104 if (ret != size) { 105 size -= ret; 106 off += ret; 107 goto retry; 108 } 109 if (!sge->length) { 110 put_page(page); 111 sk_msg_iter_next(msg, start); 112 sg_init_table(sge, 1); 113 if (msg->sg.start == msg->sg.end) 114 break; 115 } 116 if (apply && !apply_bytes) 117 break; 118 } 119 120 return 0; 121 } 122 123 static int tcp_bpf_push_locked(struct sock *sk, struct sk_msg *msg, 124 u32 apply_bytes, int flags, bool uncharge) 125 { 126 int ret; 127 128 lock_sock(sk); 129 ret = tcp_bpf_push(sk, msg, apply_bytes, flags, uncharge); 130 release_sock(sk); 131 return ret; 132 } 133 134 int tcp_bpf_sendmsg_redir(struct sock *sk, struct sk_msg *msg, 135 u32 bytes, int flags) 136 { 137 bool ingress = sk_msg_to_ingress(msg); 138 struct sk_psock *psock = sk_psock_get(sk); 139 int ret; 140 141 if (unlikely(!psock)) 142 return -EPIPE; 143 144 ret = ingress ? bpf_tcp_ingress(sk, psock, msg, bytes, flags) : 145 tcp_bpf_push_locked(sk, msg, bytes, flags, false); 146 sk_psock_put(sk, psock); 147 return ret; 148 } 149 EXPORT_SYMBOL_GPL(tcp_bpf_sendmsg_redir); 150 151 #ifdef CONFIG_BPF_SYSCALL 152 static int tcp_msg_wait_data(struct sock *sk, struct sk_psock *psock, 153 long timeo) 154 { 155 DEFINE_WAIT_FUNC(wait, woken_wake_function); 156 int ret = 0; 157 158 if (sk->sk_shutdown & RCV_SHUTDOWN) 159 return 1; 160 161 if (!timeo) 162 return ret; 163 164 add_wait_queue(sk_sleep(sk), &wait); 165 sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk); 166 ret = sk_wait_event(sk, &timeo, 167 !list_empty(&psock->ingress_msg) || 168 !skb_queue_empty(&sk->sk_receive_queue), &wait); 169 sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk); 170 remove_wait_queue(sk_sleep(sk), &wait); 171 return ret; 172 } 173 174 static int tcp_bpf_recvmsg_parser(struct sock *sk, 175 struct msghdr *msg, 176 size_t len, 177 int flags, 178 int *addr_len) 179 { 180 struct sk_psock *psock; 181 int copied; 182 183 if (unlikely(flags & MSG_ERRQUEUE)) 184 return inet_recv_error(sk, msg, len, addr_len); 185 186 psock = sk_psock_get(sk); 187 if (unlikely(!psock)) 188 return tcp_recvmsg(sk, msg, len, flags, addr_len); 189 190 lock_sock(sk); 191 msg_bytes_ready: 192 copied = sk_msg_recvmsg(sk, psock, msg, len, flags); 193 if (!copied) { 194 long timeo; 195 int data; 196 197 if (sock_flag(sk, SOCK_DONE)) 198 goto out; 199 200 if (sk->sk_err) { 201 copied = sock_error(sk); 202 goto out; 203 } 204 205 if (sk->sk_shutdown & RCV_SHUTDOWN) 206 goto out; 207 208 if (sk->sk_state == TCP_CLOSE) { 209 copied = -ENOTCONN; 210 goto out; 211 } 212 213 timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT); 214 if (!timeo) { 215 copied = -EAGAIN; 216 goto out; 217 } 218 219 if (signal_pending(current)) { 220 copied = sock_intr_errno(timeo); 221 goto out; 222 } 223 224 data = tcp_msg_wait_data(sk, psock, timeo); 225 if (data && !sk_psock_queue_empty(psock)) 226 goto msg_bytes_ready; 227 copied = -EAGAIN; 228 } 229 out: 230 release_sock(sk); 231 sk_psock_put(sk, psock); 232 return copied; 233 } 234 235 static int tcp_bpf_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, 236 int flags, int *addr_len) 237 { 238 struct sk_psock *psock; 239 int copied, ret; 240 241 if (unlikely(flags & MSG_ERRQUEUE)) 242 return inet_recv_error(sk, msg, len, addr_len); 243 244 psock = sk_psock_get(sk); 245 if (unlikely(!psock)) 246 return tcp_recvmsg(sk, msg, len, flags, addr_len); 247 if (!skb_queue_empty(&sk->sk_receive_queue) && 248 sk_psock_queue_empty(psock)) { 249 sk_psock_put(sk, psock); 250 return tcp_recvmsg(sk, msg, len, flags, addr_len); 251 } 252 lock_sock(sk); 253 msg_bytes_ready: 254 copied = sk_msg_recvmsg(sk, psock, msg, len, flags); 255 if (!copied) { 256 long timeo; 257 int data; 258 259 timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT); 260 data = tcp_msg_wait_data(sk, psock, timeo); 261 if (data) { 262 if (!sk_psock_queue_empty(psock)) 263 goto msg_bytes_ready; 264 release_sock(sk); 265 sk_psock_put(sk, psock); 266 return tcp_recvmsg(sk, msg, len, flags, addr_len); 267 } 268 copied = -EAGAIN; 269 } 270 ret = copied; 271 release_sock(sk); 272 sk_psock_put(sk, psock); 273 return ret; 274 } 275 276 static int tcp_bpf_send_verdict(struct sock *sk, struct sk_psock *psock, 277 struct sk_msg *msg, int *copied, int flags) 278 { 279 bool cork = false, enospc = sk_msg_full(msg); 280 struct sock *sk_redir; 281 u32 tosend, origsize, sent, delta = 0; 282 u32 eval; 283 int ret; 284 285 more_data: 286 if (psock->eval == __SK_NONE) { 287 /* Track delta in msg size to add/subtract it on SK_DROP from 288 * returned to user copied size. This ensures user doesn't 289 * get a positive return code with msg_cut_data and SK_DROP 290 * verdict. 291 */ 292 delta = msg->sg.size; 293 psock->eval = sk_psock_msg_verdict(sk, psock, msg); 294 delta -= msg->sg.size; 295 } 296 297 if (msg->cork_bytes && 298 msg->cork_bytes > msg->sg.size && !enospc) { 299 psock->cork_bytes = msg->cork_bytes - msg->sg.size; 300 if (!psock->cork) { 301 psock->cork = kzalloc(sizeof(*psock->cork), 302 GFP_ATOMIC | __GFP_NOWARN); 303 if (!psock->cork) 304 return -ENOMEM; 305 } 306 memcpy(psock->cork, msg, sizeof(*msg)); 307 return 0; 308 } 309 310 tosend = msg->sg.size; 311 if (psock->apply_bytes && psock->apply_bytes < tosend) 312 tosend = psock->apply_bytes; 313 eval = __SK_NONE; 314 315 switch (psock->eval) { 316 case __SK_PASS: 317 ret = tcp_bpf_push(sk, msg, tosend, flags, true); 318 if (unlikely(ret)) { 319 *copied -= sk_msg_free(sk, msg); 320 break; 321 } 322 sk_msg_apply_bytes(psock, tosend); 323 break; 324 case __SK_REDIRECT: 325 sk_redir = psock->sk_redir; 326 sk_msg_apply_bytes(psock, tosend); 327 if (!psock->apply_bytes) { 328 /* Clean up before releasing the sock lock. */ 329 eval = psock->eval; 330 psock->eval = __SK_NONE; 331 psock->sk_redir = NULL; 332 } 333 if (psock->cork) { 334 cork = true; 335 psock->cork = NULL; 336 } 337 sk_msg_return(sk, msg, tosend); 338 release_sock(sk); 339 340 origsize = msg->sg.size; 341 ret = tcp_bpf_sendmsg_redir(sk_redir, msg, tosend, flags); 342 sent = origsize - msg->sg.size; 343 344 if (eval == __SK_REDIRECT) 345 sock_put(sk_redir); 346 347 lock_sock(sk); 348 if (unlikely(ret < 0)) { 349 int free = sk_msg_free_nocharge(sk, msg); 350 351 if (!cork) 352 *copied -= free; 353 } 354 if (cork) { 355 sk_msg_free(sk, msg); 356 kfree(msg); 357 msg = NULL; 358 ret = 0; 359 } 360 break; 361 case __SK_DROP: 362 default: 363 sk_msg_free_partial(sk, msg, tosend); 364 sk_msg_apply_bytes(psock, tosend); 365 *copied -= (tosend + delta); 366 return -EACCES; 367 } 368 369 if (likely(!ret)) { 370 if (!psock->apply_bytes) { 371 psock->eval = __SK_NONE; 372 if (psock->sk_redir) { 373 sock_put(psock->sk_redir); 374 psock->sk_redir = NULL; 375 } 376 } 377 if (msg && 378 msg->sg.data[msg->sg.start].page_link && 379 msg->sg.data[msg->sg.start].length) { 380 if (eval == __SK_REDIRECT) 381 sk_mem_charge(sk, tosend - sent); 382 goto more_data; 383 } 384 } 385 return ret; 386 } 387 388 static int tcp_bpf_sendmsg(struct sock *sk, struct msghdr *msg, size_t size) 389 { 390 struct sk_msg tmp, *msg_tx = NULL; 391 int copied = 0, err = 0; 392 struct sk_psock *psock; 393 long timeo; 394 int flags; 395 396 /* Don't let internal do_tcp_sendpages() flags through */ 397 flags = (msg->msg_flags & ~MSG_SENDPAGE_DECRYPTED); 398 flags |= MSG_NO_SHARED_FRAGS; 399 400 psock = sk_psock_get(sk); 401 if (unlikely(!psock)) 402 return tcp_sendmsg(sk, msg, size); 403 404 lock_sock(sk); 405 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT); 406 while (msg_data_left(msg)) { 407 bool enospc = false; 408 u32 copy, osize; 409 410 if (sk->sk_err) { 411 err = -sk->sk_err; 412 goto out_err; 413 } 414 415 copy = msg_data_left(msg); 416 if (!sk_stream_memory_free(sk)) 417 goto wait_for_sndbuf; 418 if (psock->cork) { 419 msg_tx = psock->cork; 420 } else { 421 msg_tx = &tmp; 422 sk_msg_init(msg_tx); 423 } 424 425 osize = msg_tx->sg.size; 426 err = sk_msg_alloc(sk, msg_tx, msg_tx->sg.size + copy, msg_tx->sg.end - 1); 427 if (err) { 428 if (err != -ENOSPC) 429 goto wait_for_memory; 430 enospc = true; 431 copy = msg_tx->sg.size - osize; 432 } 433 434 err = sk_msg_memcopy_from_iter(sk, &msg->msg_iter, msg_tx, 435 copy); 436 if (err < 0) { 437 sk_msg_trim(sk, msg_tx, osize); 438 goto out_err; 439 } 440 441 copied += copy; 442 if (psock->cork_bytes) { 443 if (size > psock->cork_bytes) 444 psock->cork_bytes = 0; 445 else 446 psock->cork_bytes -= size; 447 if (psock->cork_bytes && !enospc) 448 goto out_err; 449 /* All cork bytes are accounted, rerun the prog. */ 450 psock->eval = __SK_NONE; 451 psock->cork_bytes = 0; 452 } 453 454 err = tcp_bpf_send_verdict(sk, psock, msg_tx, &copied, flags); 455 if (unlikely(err < 0)) 456 goto out_err; 457 continue; 458 wait_for_sndbuf: 459 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 460 wait_for_memory: 461 err = sk_stream_wait_memory(sk, &timeo); 462 if (err) { 463 if (msg_tx && msg_tx != psock->cork) 464 sk_msg_free(sk, msg_tx); 465 goto out_err; 466 } 467 } 468 out_err: 469 if (err < 0) 470 err = sk_stream_error(sk, msg->msg_flags, err); 471 release_sock(sk); 472 sk_psock_put(sk, psock); 473 return copied ? copied : err; 474 } 475 476 static int tcp_bpf_sendpage(struct sock *sk, struct page *page, int offset, 477 size_t size, int flags) 478 { 479 struct sk_msg tmp, *msg = NULL; 480 int err = 0, copied = 0; 481 struct sk_psock *psock; 482 bool enospc = false; 483 484 psock = sk_psock_get(sk); 485 if (unlikely(!psock)) 486 return tcp_sendpage(sk, page, offset, size, flags); 487 488 lock_sock(sk); 489 if (psock->cork) { 490 msg = psock->cork; 491 } else { 492 msg = &tmp; 493 sk_msg_init(msg); 494 } 495 496 /* Catch case where ring is full and sendpage is stalled. */ 497 if (unlikely(sk_msg_full(msg))) 498 goto out_err; 499 500 sk_msg_page_add(msg, page, size, offset); 501 sk_mem_charge(sk, size); 502 copied = size; 503 if (sk_msg_full(msg)) 504 enospc = true; 505 if (psock->cork_bytes) { 506 if (size > psock->cork_bytes) 507 psock->cork_bytes = 0; 508 else 509 psock->cork_bytes -= size; 510 if (psock->cork_bytes && !enospc) 511 goto out_err; 512 /* All cork bytes are accounted, rerun the prog. */ 513 psock->eval = __SK_NONE; 514 psock->cork_bytes = 0; 515 } 516 517 err = tcp_bpf_send_verdict(sk, psock, msg, &copied, flags); 518 out_err: 519 release_sock(sk); 520 sk_psock_put(sk, psock); 521 return copied ? copied : err; 522 } 523 524 enum { 525 TCP_BPF_IPV4, 526 TCP_BPF_IPV6, 527 TCP_BPF_NUM_PROTS, 528 }; 529 530 enum { 531 TCP_BPF_BASE, 532 TCP_BPF_TX, 533 TCP_BPF_RX, 534 TCP_BPF_TXRX, 535 TCP_BPF_NUM_CFGS, 536 }; 537 538 static struct proto *tcpv6_prot_saved __read_mostly; 539 static DEFINE_SPINLOCK(tcpv6_prot_lock); 540 static struct proto tcp_bpf_prots[TCP_BPF_NUM_PROTS][TCP_BPF_NUM_CFGS]; 541 542 static void tcp_bpf_rebuild_protos(struct proto prot[TCP_BPF_NUM_CFGS], 543 struct proto *base) 544 { 545 prot[TCP_BPF_BASE] = *base; 546 prot[TCP_BPF_BASE].destroy = sock_map_destroy; 547 prot[TCP_BPF_BASE].close = sock_map_close; 548 prot[TCP_BPF_BASE].recvmsg = tcp_bpf_recvmsg; 549 prot[TCP_BPF_BASE].sock_is_readable = sk_msg_is_readable; 550 551 prot[TCP_BPF_TX] = prot[TCP_BPF_BASE]; 552 prot[TCP_BPF_TX].sendmsg = tcp_bpf_sendmsg; 553 prot[TCP_BPF_TX].sendpage = tcp_bpf_sendpage; 554 555 prot[TCP_BPF_RX] = prot[TCP_BPF_BASE]; 556 prot[TCP_BPF_RX].recvmsg = tcp_bpf_recvmsg_parser; 557 558 prot[TCP_BPF_TXRX] = prot[TCP_BPF_TX]; 559 prot[TCP_BPF_TXRX].recvmsg = tcp_bpf_recvmsg_parser; 560 } 561 562 static void tcp_bpf_check_v6_needs_rebuild(struct proto *ops) 563 { 564 if (unlikely(ops != smp_load_acquire(&tcpv6_prot_saved))) { 565 spin_lock_bh(&tcpv6_prot_lock); 566 if (likely(ops != tcpv6_prot_saved)) { 567 tcp_bpf_rebuild_protos(tcp_bpf_prots[TCP_BPF_IPV6], ops); 568 smp_store_release(&tcpv6_prot_saved, ops); 569 } 570 spin_unlock_bh(&tcpv6_prot_lock); 571 } 572 } 573 574 static int __init tcp_bpf_v4_build_proto(void) 575 { 576 tcp_bpf_rebuild_protos(tcp_bpf_prots[TCP_BPF_IPV4], &tcp_prot); 577 return 0; 578 } 579 late_initcall(tcp_bpf_v4_build_proto); 580 581 static int tcp_bpf_assert_proto_ops(struct proto *ops) 582 { 583 /* In order to avoid retpoline, we make assumptions when we call 584 * into ops if e.g. a psock is not present. Make sure they are 585 * indeed valid assumptions. 586 */ 587 return ops->recvmsg == tcp_recvmsg && 588 ops->sendmsg == tcp_sendmsg && 589 ops->sendpage == tcp_sendpage ? 0 : -ENOTSUPP; 590 } 591 592 int tcp_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore) 593 { 594 int family = sk->sk_family == AF_INET6 ? TCP_BPF_IPV6 : TCP_BPF_IPV4; 595 int config = psock->progs.msg_parser ? TCP_BPF_TX : TCP_BPF_BASE; 596 597 if (psock->progs.stream_verdict || psock->progs.skb_verdict) { 598 config = (config == TCP_BPF_TX) ? TCP_BPF_TXRX : TCP_BPF_RX; 599 } 600 601 if (restore) { 602 if (inet_csk_has_ulp(sk)) { 603 /* TLS does not have an unhash proto in SW cases, 604 * but we need to ensure we stop using the sock_map 605 * unhash routine because the associated psock is being 606 * removed. So use the original unhash handler. 607 */ 608 WRITE_ONCE(sk->sk_prot->unhash, psock->saved_unhash); 609 tcp_update_ulp(sk, psock->sk_proto, psock->saved_write_space); 610 } else { 611 sk->sk_write_space = psock->saved_write_space; 612 /* Pairs with lockless read in sk_clone_lock() */ 613 sock_replace_proto(sk, psock->sk_proto); 614 } 615 return 0; 616 } 617 618 if (sk->sk_family == AF_INET6) { 619 if (tcp_bpf_assert_proto_ops(psock->sk_proto)) 620 return -EINVAL; 621 622 tcp_bpf_check_v6_needs_rebuild(psock->sk_proto); 623 } 624 625 /* Pairs with lockless read in sk_clone_lock() */ 626 sock_replace_proto(sk, &tcp_bpf_prots[family][config]); 627 return 0; 628 } 629 EXPORT_SYMBOL_GPL(tcp_bpf_update_proto); 630 631 /* If a child got cloned from a listening socket that had tcp_bpf 632 * protocol callbacks installed, we need to restore the callbacks to 633 * the default ones because the child does not inherit the psock state 634 * that tcp_bpf callbacks expect. 635 */ 636 void tcp_bpf_clone(const struct sock *sk, struct sock *newsk) 637 { 638 int family = sk->sk_family == AF_INET6 ? TCP_BPF_IPV6 : TCP_BPF_IPV4; 639 struct proto *prot = newsk->sk_prot; 640 641 if (prot == &tcp_bpf_prots[family][TCP_BPF_BASE]) 642 newsk->sk_prot = sk->sk_prot_creator; 643 } 644 #endif /* CONFIG_BPF_SYSCALL */ 645