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 #include <linux/util_macros.h> 10 11 #include <net/inet_common.h> 12 #include <net/tls.h> 13 14 static int bpf_tcp_ingress(struct sock *sk, struct sk_psock *psock, 15 struct sk_msg *msg, u32 apply_bytes, int flags) 16 { 17 bool apply = apply_bytes; 18 struct scatterlist *sge; 19 u32 size, copied = 0; 20 struct sk_msg *tmp; 21 int i, ret = 0; 22 23 tmp = kzalloc(sizeof(*tmp), __GFP_NOWARN | GFP_KERNEL); 24 if (unlikely(!tmp)) 25 return -ENOMEM; 26 27 lock_sock(sk); 28 tmp->sg.start = msg->sg.start; 29 i = msg->sg.start; 30 do { 31 sge = sk_msg_elem(msg, i); 32 size = (apply && apply_bytes < sge->length) ? 33 apply_bytes : sge->length; 34 if (!sk_wmem_schedule(sk, size)) { 35 if (!copied) 36 ret = -ENOMEM; 37 break; 38 } 39 40 sk_mem_charge(sk, size); 41 sk_msg_xfer(tmp, msg, i, size); 42 copied += size; 43 if (sge->length) 44 get_page(sk_msg_page(tmp, i)); 45 sk_msg_iter_var_next(i); 46 tmp->sg.end = i; 47 if (apply) { 48 apply_bytes -= size; 49 if (!apply_bytes) { 50 if (sge->length) 51 sk_msg_iter_var_prev(i); 52 break; 53 } 54 } 55 } while (i != msg->sg.end); 56 57 if (!ret) { 58 msg->sg.start = i; 59 sk_psock_queue_msg(psock, tmp); 60 sk_psock_data_ready(sk, psock); 61 } else { 62 sk_msg_free(sk, tmp); 63 kfree(tmp); 64 } 65 66 release_sock(sk); 67 return ret; 68 } 69 70 static int tcp_bpf_push(struct sock *sk, struct sk_msg *msg, u32 apply_bytes, 71 int flags, bool uncharge) 72 { 73 bool apply = apply_bytes; 74 struct scatterlist *sge; 75 struct page *page; 76 int size, ret = 0; 77 u32 off; 78 79 while (1) { 80 bool has_tx_ulp; 81 82 sge = sk_msg_elem(msg, msg->sg.start); 83 size = (apply && apply_bytes < sge->length) ? 84 apply_bytes : sge->length; 85 off = sge->offset; 86 page = sg_page(sge); 87 88 tcp_rate_check_app_limited(sk); 89 retry: 90 has_tx_ulp = tls_sw_has_ctx_tx(sk); 91 if (has_tx_ulp) { 92 flags |= MSG_SENDPAGE_NOPOLICY; 93 ret = kernel_sendpage_locked(sk, 94 page, off, size, flags); 95 } else { 96 ret = do_tcp_sendpages(sk, page, off, size, flags); 97 } 98 99 if (ret <= 0) 100 return ret; 101 if (apply) 102 apply_bytes -= ret; 103 msg->sg.size -= ret; 104 sge->offset += ret; 105 sge->length -= ret; 106 if (uncharge) 107 sk_mem_uncharge(sk, ret); 108 if (ret != size) { 109 size -= ret; 110 off += ret; 111 goto retry; 112 } 113 if (!sge->length) { 114 put_page(page); 115 sk_msg_iter_next(msg, start); 116 sg_init_table(sge, 1); 117 if (msg->sg.start == msg->sg.end) 118 break; 119 } 120 if (apply && !apply_bytes) 121 break; 122 } 123 124 return 0; 125 } 126 127 static int tcp_bpf_push_locked(struct sock *sk, struct sk_msg *msg, 128 u32 apply_bytes, int flags, bool uncharge) 129 { 130 int ret; 131 132 lock_sock(sk); 133 ret = tcp_bpf_push(sk, msg, apply_bytes, flags, uncharge); 134 release_sock(sk); 135 return ret; 136 } 137 138 int tcp_bpf_sendmsg_redir(struct sock *sk, bool ingress, 139 struct sk_msg *msg, u32 bytes, int flags) 140 { 141 struct sk_psock *psock = sk_psock_get(sk); 142 int ret; 143 144 if (unlikely(!psock)) 145 return -EPIPE; 146 147 ret = ingress ? bpf_tcp_ingress(sk, psock, msg, bytes, flags) : 148 tcp_bpf_push_locked(sk, msg, bytes, flags, false); 149 sk_psock_put(sk, psock); 150 return ret; 151 } 152 EXPORT_SYMBOL_GPL(tcp_bpf_sendmsg_redir); 153 154 #ifdef CONFIG_BPF_SYSCALL 155 static int tcp_msg_wait_data(struct sock *sk, struct sk_psock *psock, 156 long timeo) 157 { 158 DEFINE_WAIT_FUNC(wait, woken_wake_function); 159 int ret = 0; 160 161 if (sk->sk_shutdown & RCV_SHUTDOWN) 162 return 1; 163 164 if (!timeo) 165 return ret; 166 167 add_wait_queue(sk_sleep(sk), &wait); 168 sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk); 169 ret = sk_wait_event(sk, &timeo, 170 !list_empty(&psock->ingress_msg) || 171 !skb_queue_empty_lockless(&sk->sk_receive_queue), &wait); 172 sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk); 173 remove_wait_queue(sk_sleep(sk), &wait); 174 return ret; 175 } 176 177 static int tcp_bpf_recvmsg_parser(struct sock *sk, 178 struct msghdr *msg, 179 size_t len, 180 int flags, 181 int *addr_len) 182 { 183 struct sk_psock *psock; 184 int copied; 185 186 if (unlikely(flags & MSG_ERRQUEUE)) 187 return inet_recv_error(sk, msg, len, addr_len); 188 189 if (!len) 190 return 0; 191 192 psock = sk_psock_get(sk); 193 if (unlikely(!psock)) 194 return tcp_recvmsg(sk, msg, len, flags, addr_len); 195 196 lock_sock(sk); 197 msg_bytes_ready: 198 copied = sk_msg_recvmsg(sk, psock, msg, len, flags); 199 if (!copied) { 200 long timeo; 201 int data; 202 203 if (sock_flag(sk, SOCK_DONE)) 204 goto out; 205 206 if (sk->sk_err) { 207 copied = sock_error(sk); 208 goto out; 209 } 210 211 if (sk->sk_shutdown & RCV_SHUTDOWN) 212 goto out; 213 214 if (sk->sk_state == TCP_CLOSE) { 215 copied = -ENOTCONN; 216 goto out; 217 } 218 219 timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT); 220 if (!timeo) { 221 copied = -EAGAIN; 222 goto out; 223 } 224 225 if (signal_pending(current)) { 226 copied = sock_intr_errno(timeo); 227 goto out; 228 } 229 230 data = tcp_msg_wait_data(sk, psock, timeo); 231 if (data && !sk_psock_queue_empty(psock)) 232 goto msg_bytes_ready; 233 copied = -EAGAIN; 234 } 235 out: 236 release_sock(sk); 237 sk_psock_put(sk, psock); 238 return copied; 239 } 240 241 static int tcp_bpf_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, 242 int flags, int *addr_len) 243 { 244 struct sk_psock *psock; 245 int copied, ret; 246 247 if (unlikely(flags & MSG_ERRQUEUE)) 248 return inet_recv_error(sk, msg, len, addr_len); 249 250 if (!len) 251 return 0; 252 253 psock = sk_psock_get(sk); 254 if (unlikely(!psock)) 255 return tcp_recvmsg(sk, msg, len, flags, addr_len); 256 if (!skb_queue_empty(&sk->sk_receive_queue) && 257 sk_psock_queue_empty(psock)) { 258 sk_psock_put(sk, psock); 259 return tcp_recvmsg(sk, msg, len, flags, addr_len); 260 } 261 lock_sock(sk); 262 msg_bytes_ready: 263 copied = sk_msg_recvmsg(sk, psock, msg, len, flags); 264 if (!copied) { 265 long timeo; 266 int data; 267 268 timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT); 269 data = tcp_msg_wait_data(sk, psock, timeo); 270 if (data) { 271 if (!sk_psock_queue_empty(psock)) 272 goto msg_bytes_ready; 273 release_sock(sk); 274 sk_psock_put(sk, psock); 275 return tcp_recvmsg(sk, msg, len, flags, addr_len); 276 } 277 copied = -EAGAIN; 278 } 279 ret = copied; 280 release_sock(sk); 281 sk_psock_put(sk, psock); 282 return ret; 283 } 284 285 static int tcp_bpf_send_verdict(struct sock *sk, struct sk_psock *psock, 286 struct sk_msg *msg, int *copied, int flags) 287 { 288 bool cork = false, enospc = sk_msg_full(msg), redir_ingress; 289 struct sock *sk_redir; 290 u32 tosend, origsize, sent, delta = 0; 291 u32 eval; 292 int ret; 293 294 more_data: 295 if (psock->eval == __SK_NONE) { 296 /* Track delta in msg size to add/subtract it on SK_DROP from 297 * returned to user copied size. This ensures user doesn't 298 * get a positive return code with msg_cut_data and SK_DROP 299 * verdict. 300 */ 301 delta = msg->sg.size; 302 psock->eval = sk_psock_msg_verdict(sk, psock, msg); 303 delta -= msg->sg.size; 304 } 305 306 if (msg->cork_bytes && 307 msg->cork_bytes > msg->sg.size && !enospc) { 308 psock->cork_bytes = msg->cork_bytes - msg->sg.size; 309 if (!psock->cork) { 310 psock->cork = kzalloc(sizeof(*psock->cork), 311 GFP_ATOMIC | __GFP_NOWARN); 312 if (!psock->cork) 313 return -ENOMEM; 314 } 315 memcpy(psock->cork, msg, sizeof(*msg)); 316 return 0; 317 } 318 319 tosend = msg->sg.size; 320 if (psock->apply_bytes && psock->apply_bytes < tosend) 321 tosend = psock->apply_bytes; 322 eval = __SK_NONE; 323 324 switch (psock->eval) { 325 case __SK_PASS: 326 ret = tcp_bpf_push(sk, msg, tosend, flags, true); 327 if (unlikely(ret)) { 328 *copied -= sk_msg_free(sk, msg); 329 break; 330 } 331 sk_msg_apply_bytes(psock, tosend); 332 break; 333 case __SK_REDIRECT: 334 redir_ingress = psock->redir_ingress; 335 sk_redir = psock->sk_redir; 336 sk_msg_apply_bytes(psock, tosend); 337 if (!psock->apply_bytes) { 338 /* Clean up before releasing the sock lock. */ 339 eval = psock->eval; 340 psock->eval = __SK_NONE; 341 psock->sk_redir = NULL; 342 } 343 if (psock->cork) { 344 cork = true; 345 psock->cork = NULL; 346 } 347 sk_msg_return(sk, msg, tosend); 348 release_sock(sk); 349 350 origsize = msg->sg.size; 351 ret = tcp_bpf_sendmsg_redir(sk_redir, redir_ingress, 352 msg, tosend, flags); 353 sent = origsize - msg->sg.size; 354 355 if (eval == __SK_REDIRECT) 356 sock_put(sk_redir); 357 358 lock_sock(sk); 359 if (unlikely(ret < 0)) { 360 int free = sk_msg_free_nocharge(sk, msg); 361 362 if (!cork) 363 *copied -= free; 364 } 365 if (cork) { 366 sk_msg_free(sk, msg); 367 kfree(msg); 368 msg = NULL; 369 ret = 0; 370 } 371 break; 372 case __SK_DROP: 373 default: 374 sk_msg_free_partial(sk, msg, tosend); 375 sk_msg_apply_bytes(psock, tosend); 376 *copied -= (tosend + delta); 377 return -EACCES; 378 } 379 380 if (likely(!ret)) { 381 if (!psock->apply_bytes) { 382 psock->eval = __SK_NONE; 383 if (psock->sk_redir) { 384 sock_put(psock->sk_redir); 385 psock->sk_redir = NULL; 386 } 387 } 388 if (msg && 389 msg->sg.data[msg->sg.start].page_link && 390 msg->sg.data[msg->sg.start].length) { 391 if (eval == __SK_REDIRECT) 392 sk_mem_charge(sk, tosend - sent); 393 goto more_data; 394 } 395 } 396 return ret; 397 } 398 399 static int tcp_bpf_sendmsg(struct sock *sk, struct msghdr *msg, size_t size) 400 { 401 struct sk_msg tmp, *msg_tx = NULL; 402 int copied = 0, err = 0; 403 struct sk_psock *psock; 404 long timeo; 405 int flags; 406 407 /* Don't let internal do_tcp_sendpages() flags through */ 408 flags = (msg->msg_flags & ~MSG_SENDPAGE_DECRYPTED); 409 flags |= MSG_NO_SHARED_FRAGS; 410 411 psock = sk_psock_get(sk); 412 if (unlikely(!psock)) 413 return tcp_sendmsg(sk, msg, size); 414 415 lock_sock(sk); 416 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT); 417 while (msg_data_left(msg)) { 418 bool enospc = false; 419 u32 copy, osize; 420 421 if (sk->sk_err) { 422 err = -sk->sk_err; 423 goto out_err; 424 } 425 426 copy = msg_data_left(msg); 427 if (!sk_stream_memory_free(sk)) 428 goto wait_for_sndbuf; 429 if (psock->cork) { 430 msg_tx = psock->cork; 431 } else { 432 msg_tx = &tmp; 433 sk_msg_init(msg_tx); 434 } 435 436 osize = msg_tx->sg.size; 437 err = sk_msg_alloc(sk, msg_tx, msg_tx->sg.size + copy, msg_tx->sg.end - 1); 438 if (err) { 439 if (err != -ENOSPC) 440 goto wait_for_memory; 441 enospc = true; 442 copy = msg_tx->sg.size - osize; 443 } 444 445 err = sk_msg_memcopy_from_iter(sk, &msg->msg_iter, msg_tx, 446 copy); 447 if (err < 0) { 448 sk_msg_trim(sk, msg_tx, osize); 449 goto out_err; 450 } 451 452 copied += copy; 453 if (psock->cork_bytes) { 454 if (size > psock->cork_bytes) 455 psock->cork_bytes = 0; 456 else 457 psock->cork_bytes -= size; 458 if (psock->cork_bytes && !enospc) 459 goto out_err; 460 /* All cork bytes are accounted, rerun the prog. */ 461 psock->eval = __SK_NONE; 462 psock->cork_bytes = 0; 463 } 464 465 err = tcp_bpf_send_verdict(sk, psock, msg_tx, &copied, flags); 466 if (unlikely(err < 0)) 467 goto out_err; 468 continue; 469 wait_for_sndbuf: 470 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 471 wait_for_memory: 472 err = sk_stream_wait_memory(sk, &timeo); 473 if (err) { 474 if (msg_tx && msg_tx != psock->cork) 475 sk_msg_free(sk, msg_tx); 476 goto out_err; 477 } 478 } 479 out_err: 480 if (err < 0) 481 err = sk_stream_error(sk, msg->msg_flags, err); 482 release_sock(sk); 483 sk_psock_put(sk, psock); 484 return copied ? copied : err; 485 } 486 487 static int tcp_bpf_sendpage(struct sock *sk, struct page *page, int offset, 488 size_t size, int flags) 489 { 490 struct sk_msg tmp, *msg = NULL; 491 int err = 0, copied = 0; 492 struct sk_psock *psock; 493 bool enospc = false; 494 495 psock = sk_psock_get(sk); 496 if (unlikely(!psock)) 497 return tcp_sendpage(sk, page, offset, size, flags); 498 499 lock_sock(sk); 500 if (psock->cork) { 501 msg = psock->cork; 502 } else { 503 msg = &tmp; 504 sk_msg_init(msg); 505 } 506 507 /* Catch case where ring is full and sendpage is stalled. */ 508 if (unlikely(sk_msg_full(msg))) 509 goto out_err; 510 511 sk_msg_page_add(msg, page, size, offset); 512 sk_mem_charge(sk, size); 513 copied = size; 514 if (sk_msg_full(msg)) 515 enospc = true; 516 if (psock->cork_bytes) { 517 if (size > psock->cork_bytes) 518 psock->cork_bytes = 0; 519 else 520 psock->cork_bytes -= size; 521 if (psock->cork_bytes && !enospc) 522 goto out_err; 523 /* All cork bytes are accounted, rerun the prog. */ 524 psock->eval = __SK_NONE; 525 psock->cork_bytes = 0; 526 } 527 528 err = tcp_bpf_send_verdict(sk, psock, msg, &copied, flags); 529 out_err: 530 release_sock(sk); 531 sk_psock_put(sk, psock); 532 return copied ? copied : err; 533 } 534 535 enum { 536 TCP_BPF_IPV4, 537 TCP_BPF_IPV6, 538 TCP_BPF_NUM_PROTS, 539 }; 540 541 enum { 542 TCP_BPF_BASE, 543 TCP_BPF_TX, 544 TCP_BPF_RX, 545 TCP_BPF_TXRX, 546 TCP_BPF_NUM_CFGS, 547 }; 548 549 static struct proto *tcpv6_prot_saved __read_mostly; 550 static DEFINE_SPINLOCK(tcpv6_prot_lock); 551 static struct proto tcp_bpf_prots[TCP_BPF_NUM_PROTS][TCP_BPF_NUM_CFGS]; 552 553 static void tcp_bpf_rebuild_protos(struct proto prot[TCP_BPF_NUM_CFGS], 554 struct proto *base) 555 { 556 prot[TCP_BPF_BASE] = *base; 557 prot[TCP_BPF_BASE].destroy = sock_map_destroy; 558 prot[TCP_BPF_BASE].close = sock_map_close; 559 prot[TCP_BPF_BASE].recvmsg = tcp_bpf_recvmsg; 560 prot[TCP_BPF_BASE].sock_is_readable = sk_msg_is_readable; 561 562 prot[TCP_BPF_TX] = prot[TCP_BPF_BASE]; 563 prot[TCP_BPF_TX].sendmsg = tcp_bpf_sendmsg; 564 prot[TCP_BPF_TX].sendpage = tcp_bpf_sendpage; 565 566 prot[TCP_BPF_RX] = prot[TCP_BPF_BASE]; 567 prot[TCP_BPF_RX].recvmsg = tcp_bpf_recvmsg_parser; 568 569 prot[TCP_BPF_TXRX] = prot[TCP_BPF_TX]; 570 prot[TCP_BPF_TXRX].recvmsg = tcp_bpf_recvmsg_parser; 571 } 572 573 static void tcp_bpf_check_v6_needs_rebuild(struct proto *ops) 574 { 575 if (unlikely(ops != smp_load_acquire(&tcpv6_prot_saved))) { 576 spin_lock_bh(&tcpv6_prot_lock); 577 if (likely(ops != tcpv6_prot_saved)) { 578 tcp_bpf_rebuild_protos(tcp_bpf_prots[TCP_BPF_IPV6], ops); 579 smp_store_release(&tcpv6_prot_saved, ops); 580 } 581 spin_unlock_bh(&tcpv6_prot_lock); 582 } 583 } 584 585 static int __init tcp_bpf_v4_build_proto(void) 586 { 587 tcp_bpf_rebuild_protos(tcp_bpf_prots[TCP_BPF_IPV4], &tcp_prot); 588 return 0; 589 } 590 late_initcall(tcp_bpf_v4_build_proto); 591 592 static int tcp_bpf_assert_proto_ops(struct proto *ops) 593 { 594 /* In order to avoid retpoline, we make assumptions when we call 595 * into ops if e.g. a psock is not present. Make sure they are 596 * indeed valid assumptions. 597 */ 598 return ops->recvmsg == tcp_recvmsg && 599 ops->sendmsg == tcp_sendmsg && 600 ops->sendpage == tcp_sendpage ? 0 : -ENOTSUPP; 601 } 602 603 int tcp_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore) 604 { 605 int family = sk->sk_family == AF_INET6 ? TCP_BPF_IPV6 : TCP_BPF_IPV4; 606 int config = psock->progs.msg_parser ? TCP_BPF_TX : TCP_BPF_BASE; 607 608 if (psock->progs.stream_verdict || psock->progs.skb_verdict) { 609 config = (config == TCP_BPF_TX) ? TCP_BPF_TXRX : TCP_BPF_RX; 610 } 611 612 if (restore) { 613 if (inet_csk_has_ulp(sk)) { 614 /* TLS does not have an unhash proto in SW cases, 615 * but we need to ensure we stop using the sock_map 616 * unhash routine because the associated psock is being 617 * removed. So use the original unhash handler. 618 */ 619 WRITE_ONCE(sk->sk_prot->unhash, psock->saved_unhash); 620 tcp_update_ulp(sk, psock->sk_proto, psock->saved_write_space); 621 } else { 622 sk->sk_write_space = psock->saved_write_space; 623 /* Pairs with lockless read in sk_clone_lock() */ 624 sock_replace_proto(sk, psock->sk_proto); 625 } 626 return 0; 627 } 628 629 if (sk->sk_family == AF_INET6) { 630 if (tcp_bpf_assert_proto_ops(psock->sk_proto)) 631 return -EINVAL; 632 633 tcp_bpf_check_v6_needs_rebuild(psock->sk_proto); 634 } 635 636 /* Pairs with lockless read in sk_clone_lock() */ 637 sock_replace_proto(sk, &tcp_bpf_prots[family][config]); 638 return 0; 639 } 640 EXPORT_SYMBOL_GPL(tcp_bpf_update_proto); 641 642 /* If a child got cloned from a listening socket that had tcp_bpf 643 * protocol callbacks installed, we need to restore the callbacks to 644 * the default ones because the child does not inherit the psock state 645 * that tcp_bpf callbacks expect. 646 */ 647 void tcp_bpf_clone(const struct sock *sk, struct sock *newsk) 648 { 649 struct proto *prot = newsk->sk_prot; 650 651 if (is_insidevar(prot, tcp_bpf_prots)) 652 newsk->sk_prot = sk->sk_prot_creator; 653 } 654 #endif /* CONFIG_BPF_SYSCALL */ 655