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 nonblock, 178 int flags, 179 int *addr_len) 180 { 181 struct sk_psock *psock; 182 int copied; 183 184 if (unlikely(flags & MSG_ERRQUEUE)) 185 return inet_recv_error(sk, msg, len, addr_len); 186 187 psock = sk_psock_get(sk); 188 if (unlikely(!psock)) 189 return tcp_recvmsg(sk, msg, len, nonblock, flags, addr_len); 190 191 lock_sock(sk); 192 msg_bytes_ready: 193 copied = sk_msg_recvmsg(sk, psock, msg, len, flags); 194 if (!copied) { 195 long timeo; 196 int data; 197 198 if (sock_flag(sk, SOCK_DONE)) 199 goto out; 200 201 if (sk->sk_err) { 202 copied = sock_error(sk); 203 goto out; 204 } 205 206 if (sk->sk_shutdown & RCV_SHUTDOWN) 207 goto out; 208 209 if (sk->sk_state == TCP_CLOSE) { 210 copied = -ENOTCONN; 211 goto out; 212 } 213 214 timeo = sock_rcvtimeo(sk, nonblock); 215 if (!timeo) { 216 copied = -EAGAIN; 217 goto out; 218 } 219 220 if (signal_pending(current)) { 221 copied = sock_intr_errno(timeo); 222 goto out; 223 } 224 225 data = tcp_msg_wait_data(sk, psock, timeo); 226 if (data && !sk_psock_queue_empty(psock)) 227 goto msg_bytes_ready; 228 copied = -EAGAIN; 229 } 230 out: 231 release_sock(sk); 232 sk_psock_put(sk, psock); 233 return copied; 234 } 235 236 static int tcp_bpf_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, 237 int nonblock, int flags, int *addr_len) 238 { 239 struct sk_psock *psock; 240 int copied, ret; 241 242 if (unlikely(flags & MSG_ERRQUEUE)) 243 return inet_recv_error(sk, msg, len, addr_len); 244 245 psock = sk_psock_get(sk); 246 if (unlikely(!psock)) 247 return tcp_recvmsg(sk, msg, len, nonblock, flags, addr_len); 248 if (!skb_queue_empty(&sk->sk_receive_queue) && 249 sk_psock_queue_empty(psock)) { 250 sk_psock_put(sk, psock); 251 return tcp_recvmsg(sk, msg, len, nonblock, flags, addr_len); 252 } 253 lock_sock(sk); 254 msg_bytes_ready: 255 copied = sk_msg_recvmsg(sk, psock, msg, len, flags); 256 if (!copied) { 257 long timeo; 258 int data; 259 260 timeo = sock_rcvtimeo(sk, nonblock); 261 data = tcp_msg_wait_data(sk, psock, timeo); 262 if (data) { 263 if (!sk_psock_queue_empty(psock)) 264 goto msg_bytes_ready; 265 release_sock(sk); 266 sk_psock_put(sk, psock); 267 return tcp_recvmsg(sk, msg, len, nonblock, flags, addr_len); 268 } 269 copied = -EAGAIN; 270 } 271 ret = copied; 272 release_sock(sk); 273 sk_psock_put(sk, psock); 274 return ret; 275 } 276 277 static int tcp_bpf_send_verdict(struct sock *sk, struct sk_psock *psock, 278 struct sk_msg *msg, int *copied, int flags) 279 { 280 bool cork = false, enospc = sk_msg_full(msg); 281 struct sock *sk_redir; 282 u32 tosend, delta = 0; 283 u32 eval = __SK_NONE; 284 int ret; 285 286 more_data: 287 if (psock->eval == __SK_NONE) { 288 /* Track delta in msg size to add/subtract it on SK_DROP from 289 * returned to user copied size. This ensures user doesn't 290 * get a positive return code with msg_cut_data and SK_DROP 291 * verdict. 292 */ 293 delta = msg->sg.size; 294 psock->eval = sk_psock_msg_verdict(sk, psock, msg); 295 delta -= msg->sg.size; 296 } 297 298 if (msg->cork_bytes && 299 msg->cork_bytes > msg->sg.size && !enospc) { 300 psock->cork_bytes = msg->cork_bytes - msg->sg.size; 301 if (!psock->cork) { 302 psock->cork = kzalloc(sizeof(*psock->cork), 303 GFP_ATOMIC | __GFP_NOWARN); 304 if (!psock->cork) 305 return -ENOMEM; 306 } 307 memcpy(psock->cork, msg, sizeof(*msg)); 308 return 0; 309 } 310 311 tosend = msg->sg.size; 312 if (psock->apply_bytes && psock->apply_bytes < tosend) 313 tosend = psock->apply_bytes; 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, msg->sg.size); 338 release_sock(sk); 339 340 ret = tcp_bpf_sendmsg_redir(sk_redir, msg, tosend, flags); 341 342 if (eval == __SK_REDIRECT) 343 sock_put(sk_redir); 344 345 lock_sock(sk); 346 if (unlikely(ret < 0)) { 347 int free = sk_msg_free_nocharge(sk, msg); 348 349 if (!cork) 350 *copied -= free; 351 } 352 if (cork) { 353 sk_msg_free(sk, msg); 354 kfree(msg); 355 msg = NULL; 356 ret = 0; 357 } 358 break; 359 case __SK_DROP: 360 default: 361 sk_msg_free_partial(sk, msg, tosend); 362 sk_msg_apply_bytes(psock, tosend); 363 *copied -= (tosend + delta); 364 return -EACCES; 365 } 366 367 if (likely(!ret)) { 368 if (!psock->apply_bytes) { 369 psock->eval = __SK_NONE; 370 if (psock->sk_redir) { 371 sock_put(psock->sk_redir); 372 psock->sk_redir = NULL; 373 } 374 } 375 if (msg && 376 msg->sg.data[msg->sg.start].page_link && 377 msg->sg.data[msg->sg.start].length) { 378 if (eval == __SK_REDIRECT) 379 sk_mem_charge(sk, msg->sg.size); 380 goto more_data; 381 } 382 } 383 return ret; 384 } 385 386 static int tcp_bpf_sendmsg(struct sock *sk, struct msghdr *msg, size_t size) 387 { 388 struct sk_msg tmp, *msg_tx = NULL; 389 int copied = 0, err = 0; 390 struct sk_psock *psock; 391 long timeo; 392 int flags; 393 394 /* Don't let internal do_tcp_sendpages() flags through */ 395 flags = (msg->msg_flags & ~MSG_SENDPAGE_DECRYPTED); 396 flags |= MSG_NO_SHARED_FRAGS; 397 398 psock = sk_psock_get(sk); 399 if (unlikely(!psock)) 400 return tcp_sendmsg(sk, msg, size); 401 402 lock_sock(sk); 403 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT); 404 while (msg_data_left(msg)) { 405 bool enospc = false; 406 u32 copy, osize; 407 408 if (sk->sk_err) { 409 err = -sk->sk_err; 410 goto out_err; 411 } 412 413 copy = msg_data_left(msg); 414 if (!sk_stream_memory_free(sk)) 415 goto wait_for_sndbuf; 416 if (psock->cork) { 417 msg_tx = psock->cork; 418 } else { 419 msg_tx = &tmp; 420 sk_msg_init(msg_tx); 421 } 422 423 osize = msg_tx->sg.size; 424 err = sk_msg_alloc(sk, msg_tx, msg_tx->sg.size + copy, msg_tx->sg.end - 1); 425 if (err) { 426 if (err != -ENOSPC) 427 goto wait_for_memory; 428 enospc = true; 429 copy = msg_tx->sg.size - osize; 430 } 431 432 err = sk_msg_memcopy_from_iter(sk, &msg->msg_iter, msg_tx, 433 copy); 434 if (err < 0) { 435 sk_msg_trim(sk, msg_tx, osize); 436 goto out_err; 437 } 438 439 copied += copy; 440 if (psock->cork_bytes) { 441 if (size > psock->cork_bytes) 442 psock->cork_bytes = 0; 443 else 444 psock->cork_bytes -= size; 445 if (psock->cork_bytes && !enospc) 446 goto out_err; 447 /* All cork bytes are accounted, rerun the prog. */ 448 psock->eval = __SK_NONE; 449 psock->cork_bytes = 0; 450 } 451 452 err = tcp_bpf_send_verdict(sk, psock, msg_tx, &copied, flags); 453 if (unlikely(err < 0)) 454 goto out_err; 455 continue; 456 wait_for_sndbuf: 457 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 458 wait_for_memory: 459 err = sk_stream_wait_memory(sk, &timeo); 460 if (err) { 461 if (msg_tx && msg_tx != psock->cork) 462 sk_msg_free(sk, msg_tx); 463 goto out_err; 464 } 465 } 466 out_err: 467 if (err < 0) 468 err = sk_stream_error(sk, msg->msg_flags, err); 469 release_sock(sk); 470 sk_psock_put(sk, psock); 471 return copied ? copied : err; 472 } 473 474 static int tcp_bpf_sendpage(struct sock *sk, struct page *page, int offset, 475 size_t size, int flags) 476 { 477 struct sk_msg tmp, *msg = NULL; 478 int err = 0, copied = 0; 479 struct sk_psock *psock; 480 bool enospc = false; 481 482 psock = sk_psock_get(sk); 483 if (unlikely(!psock)) 484 return tcp_sendpage(sk, page, offset, size, flags); 485 486 lock_sock(sk); 487 if (psock->cork) { 488 msg = psock->cork; 489 } else { 490 msg = &tmp; 491 sk_msg_init(msg); 492 } 493 494 /* Catch case where ring is full and sendpage is stalled. */ 495 if (unlikely(sk_msg_full(msg))) 496 goto out_err; 497 498 sk_msg_page_add(msg, page, size, offset); 499 sk_mem_charge(sk, size); 500 copied = size; 501 if (sk_msg_full(msg)) 502 enospc = true; 503 if (psock->cork_bytes) { 504 if (size > psock->cork_bytes) 505 psock->cork_bytes = 0; 506 else 507 psock->cork_bytes -= size; 508 if (psock->cork_bytes && !enospc) 509 goto out_err; 510 /* All cork bytes are accounted, rerun the prog. */ 511 psock->eval = __SK_NONE; 512 psock->cork_bytes = 0; 513 } 514 515 err = tcp_bpf_send_verdict(sk, psock, msg, &copied, flags); 516 out_err: 517 release_sock(sk); 518 sk_psock_put(sk, psock); 519 return copied ? copied : err; 520 } 521 522 enum { 523 TCP_BPF_IPV4, 524 TCP_BPF_IPV6, 525 TCP_BPF_NUM_PROTS, 526 }; 527 528 enum { 529 TCP_BPF_BASE, 530 TCP_BPF_TX, 531 TCP_BPF_RX, 532 TCP_BPF_TXRX, 533 TCP_BPF_NUM_CFGS, 534 }; 535 536 static struct proto *tcpv6_prot_saved __read_mostly; 537 static DEFINE_SPINLOCK(tcpv6_prot_lock); 538 static struct proto tcp_bpf_prots[TCP_BPF_NUM_PROTS][TCP_BPF_NUM_CFGS]; 539 540 static void tcp_bpf_rebuild_protos(struct proto prot[TCP_BPF_NUM_CFGS], 541 struct proto *base) 542 { 543 prot[TCP_BPF_BASE] = *base; 544 prot[TCP_BPF_BASE].close = sock_map_close; 545 prot[TCP_BPF_BASE].recvmsg = tcp_bpf_recvmsg; 546 prot[TCP_BPF_BASE].sock_is_readable = sk_msg_is_readable; 547 548 prot[TCP_BPF_TX] = prot[TCP_BPF_BASE]; 549 prot[TCP_BPF_TX].sendmsg = tcp_bpf_sendmsg; 550 prot[TCP_BPF_TX].sendpage = tcp_bpf_sendpage; 551 552 prot[TCP_BPF_RX] = prot[TCP_BPF_BASE]; 553 prot[TCP_BPF_RX].recvmsg = tcp_bpf_recvmsg_parser; 554 555 prot[TCP_BPF_TXRX] = prot[TCP_BPF_TX]; 556 prot[TCP_BPF_TXRX].recvmsg = tcp_bpf_recvmsg_parser; 557 } 558 559 static void tcp_bpf_check_v6_needs_rebuild(struct proto *ops) 560 { 561 if (unlikely(ops != smp_load_acquire(&tcpv6_prot_saved))) { 562 spin_lock_bh(&tcpv6_prot_lock); 563 if (likely(ops != tcpv6_prot_saved)) { 564 tcp_bpf_rebuild_protos(tcp_bpf_prots[TCP_BPF_IPV6], ops); 565 smp_store_release(&tcpv6_prot_saved, ops); 566 } 567 spin_unlock_bh(&tcpv6_prot_lock); 568 } 569 } 570 571 static int __init tcp_bpf_v4_build_proto(void) 572 { 573 tcp_bpf_rebuild_protos(tcp_bpf_prots[TCP_BPF_IPV4], &tcp_prot); 574 return 0; 575 } 576 late_initcall(tcp_bpf_v4_build_proto); 577 578 static int tcp_bpf_assert_proto_ops(struct proto *ops) 579 { 580 /* In order to avoid retpoline, we make assumptions when we call 581 * into ops if e.g. a psock is not present. Make sure they are 582 * indeed valid assumptions. 583 */ 584 return ops->recvmsg == tcp_recvmsg && 585 ops->sendmsg == tcp_sendmsg && 586 ops->sendpage == tcp_sendpage ? 0 : -ENOTSUPP; 587 } 588 589 int tcp_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore) 590 { 591 int family = sk->sk_family == AF_INET6 ? TCP_BPF_IPV6 : TCP_BPF_IPV4; 592 int config = psock->progs.msg_parser ? TCP_BPF_TX : TCP_BPF_BASE; 593 594 if (psock->progs.stream_verdict || psock->progs.skb_verdict) { 595 config = (config == TCP_BPF_TX) ? TCP_BPF_TXRX : TCP_BPF_RX; 596 } 597 598 if (restore) { 599 if (inet_csk_has_ulp(sk)) { 600 /* TLS does not have an unhash proto in SW cases, 601 * but we need to ensure we stop using the sock_map 602 * unhash routine because the associated psock is being 603 * removed. So use the original unhash handler. 604 */ 605 WRITE_ONCE(sk->sk_prot->unhash, psock->saved_unhash); 606 tcp_update_ulp(sk, psock->sk_proto, psock->saved_write_space); 607 } else { 608 sk->sk_write_space = psock->saved_write_space; 609 /* Pairs with lockless read in sk_clone_lock() */ 610 WRITE_ONCE(sk->sk_prot, psock->sk_proto); 611 } 612 return 0; 613 } 614 615 if (inet_csk_has_ulp(sk)) 616 return -EINVAL; 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 WRITE_ONCE(sk->sk_prot, &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