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, delta = 0; 282 u32 eval = __SK_NONE; 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; 313 314 switch (psock->eval) { 315 case __SK_PASS: 316 ret = tcp_bpf_push(sk, msg, tosend, flags, true); 317 if (unlikely(ret)) { 318 *copied -= sk_msg_free(sk, msg); 319 break; 320 } 321 sk_msg_apply_bytes(psock, tosend); 322 break; 323 case __SK_REDIRECT: 324 sk_redir = psock->sk_redir; 325 sk_msg_apply_bytes(psock, tosend); 326 if (!psock->apply_bytes) { 327 /* Clean up before releasing the sock lock. */ 328 eval = psock->eval; 329 psock->eval = __SK_NONE; 330 psock->sk_redir = NULL; 331 } 332 if (psock->cork) { 333 cork = true; 334 psock->cork = NULL; 335 } 336 sk_msg_return(sk, msg, msg->sg.size); 337 release_sock(sk); 338 339 ret = tcp_bpf_sendmsg_redir(sk_redir, msg, tosend, flags); 340 341 if (eval == __SK_REDIRECT) 342 sock_put(sk_redir); 343 344 lock_sock(sk); 345 if (unlikely(ret < 0)) { 346 int free = sk_msg_free_nocharge(sk, msg); 347 348 if (!cork) 349 *copied -= free; 350 } 351 if (cork) { 352 sk_msg_free(sk, msg); 353 kfree(msg); 354 msg = NULL; 355 ret = 0; 356 } 357 break; 358 case __SK_DROP: 359 default: 360 sk_msg_free_partial(sk, msg, tosend); 361 sk_msg_apply_bytes(psock, tosend); 362 *copied -= (tosend + delta); 363 return -EACCES; 364 } 365 366 if (likely(!ret)) { 367 if (!psock->apply_bytes) { 368 psock->eval = __SK_NONE; 369 if (psock->sk_redir) { 370 sock_put(psock->sk_redir); 371 psock->sk_redir = NULL; 372 } 373 } 374 if (msg && 375 msg->sg.data[msg->sg.start].page_link && 376 msg->sg.data[msg->sg.start].length) { 377 if (eval == __SK_REDIRECT) 378 sk_mem_charge(sk, msg->sg.size); 379 goto more_data; 380 } 381 } 382 return ret; 383 } 384 385 static int tcp_bpf_sendmsg(struct sock *sk, struct msghdr *msg, size_t size) 386 { 387 struct sk_msg tmp, *msg_tx = NULL; 388 int copied = 0, err = 0; 389 struct sk_psock *psock; 390 long timeo; 391 int flags; 392 393 /* Don't let internal do_tcp_sendpages() flags through */ 394 flags = (msg->msg_flags & ~MSG_SENDPAGE_DECRYPTED); 395 flags |= MSG_NO_SHARED_FRAGS; 396 397 psock = sk_psock_get(sk); 398 if (unlikely(!psock)) 399 return tcp_sendmsg(sk, msg, size); 400 401 lock_sock(sk); 402 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT); 403 while (msg_data_left(msg)) { 404 bool enospc = false; 405 u32 copy, osize; 406 407 if (sk->sk_err) { 408 err = -sk->sk_err; 409 goto out_err; 410 } 411 412 copy = msg_data_left(msg); 413 if (!sk_stream_memory_free(sk)) 414 goto wait_for_sndbuf; 415 if (psock->cork) { 416 msg_tx = psock->cork; 417 } else { 418 msg_tx = &tmp; 419 sk_msg_init(msg_tx); 420 } 421 422 osize = msg_tx->sg.size; 423 err = sk_msg_alloc(sk, msg_tx, msg_tx->sg.size + copy, msg_tx->sg.end - 1); 424 if (err) { 425 if (err != -ENOSPC) 426 goto wait_for_memory; 427 enospc = true; 428 copy = msg_tx->sg.size - osize; 429 } 430 431 err = sk_msg_memcopy_from_iter(sk, &msg->msg_iter, msg_tx, 432 copy); 433 if (err < 0) { 434 sk_msg_trim(sk, msg_tx, osize); 435 goto out_err; 436 } 437 438 copied += copy; 439 if (psock->cork_bytes) { 440 if (size > psock->cork_bytes) 441 psock->cork_bytes = 0; 442 else 443 psock->cork_bytes -= size; 444 if (psock->cork_bytes && !enospc) 445 goto out_err; 446 /* All cork bytes are accounted, rerun the prog. */ 447 psock->eval = __SK_NONE; 448 psock->cork_bytes = 0; 449 } 450 451 err = tcp_bpf_send_verdict(sk, psock, msg_tx, &copied, flags); 452 if (unlikely(err < 0)) 453 goto out_err; 454 continue; 455 wait_for_sndbuf: 456 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 457 wait_for_memory: 458 err = sk_stream_wait_memory(sk, &timeo); 459 if (err) { 460 if (msg_tx && msg_tx != psock->cork) 461 sk_msg_free(sk, msg_tx); 462 goto out_err; 463 } 464 } 465 out_err: 466 if (err < 0) 467 err = sk_stream_error(sk, msg->msg_flags, err); 468 release_sock(sk); 469 sk_psock_put(sk, psock); 470 return copied ? copied : err; 471 } 472 473 static int tcp_bpf_sendpage(struct sock *sk, struct page *page, int offset, 474 size_t size, int flags) 475 { 476 struct sk_msg tmp, *msg = NULL; 477 int err = 0, copied = 0; 478 struct sk_psock *psock; 479 bool enospc = false; 480 481 psock = sk_psock_get(sk); 482 if (unlikely(!psock)) 483 return tcp_sendpage(sk, page, offset, size, flags); 484 485 lock_sock(sk); 486 if (psock->cork) { 487 msg = psock->cork; 488 } else { 489 msg = &tmp; 490 sk_msg_init(msg); 491 } 492 493 /* Catch case where ring is full and sendpage is stalled. */ 494 if (unlikely(sk_msg_full(msg))) 495 goto out_err; 496 497 sk_msg_page_add(msg, page, size, offset); 498 sk_mem_charge(sk, size); 499 copied = size; 500 if (sk_msg_full(msg)) 501 enospc = true; 502 if (psock->cork_bytes) { 503 if (size > psock->cork_bytes) 504 psock->cork_bytes = 0; 505 else 506 psock->cork_bytes -= size; 507 if (psock->cork_bytes && !enospc) 508 goto out_err; 509 /* All cork bytes are accounted, rerun the prog. */ 510 psock->eval = __SK_NONE; 511 psock->cork_bytes = 0; 512 } 513 514 err = tcp_bpf_send_verdict(sk, psock, msg, &copied, flags); 515 out_err: 516 release_sock(sk); 517 sk_psock_put(sk, psock); 518 return copied ? copied : err; 519 } 520 521 enum { 522 TCP_BPF_IPV4, 523 TCP_BPF_IPV6, 524 TCP_BPF_NUM_PROTS, 525 }; 526 527 enum { 528 TCP_BPF_BASE, 529 TCP_BPF_TX, 530 TCP_BPF_RX, 531 TCP_BPF_TXRX, 532 TCP_BPF_NUM_CFGS, 533 }; 534 535 static struct proto *tcpv6_prot_saved __read_mostly; 536 static DEFINE_SPINLOCK(tcpv6_prot_lock); 537 static struct proto tcp_bpf_prots[TCP_BPF_NUM_PROTS][TCP_BPF_NUM_CFGS]; 538 539 static void tcp_bpf_rebuild_protos(struct proto prot[TCP_BPF_NUM_CFGS], 540 struct proto *base) 541 { 542 prot[TCP_BPF_BASE] = *base; 543 prot[TCP_BPF_BASE].close = sock_map_close; 544 prot[TCP_BPF_BASE].recvmsg = tcp_bpf_recvmsg; 545 prot[TCP_BPF_BASE].sock_is_readable = sk_msg_is_readable; 546 547 prot[TCP_BPF_TX] = prot[TCP_BPF_BASE]; 548 prot[TCP_BPF_TX].sendmsg = tcp_bpf_sendmsg; 549 prot[TCP_BPF_TX].sendpage = tcp_bpf_sendpage; 550 551 prot[TCP_BPF_RX] = prot[TCP_BPF_BASE]; 552 prot[TCP_BPF_RX].recvmsg = tcp_bpf_recvmsg_parser; 553 554 prot[TCP_BPF_TXRX] = prot[TCP_BPF_TX]; 555 prot[TCP_BPF_TXRX].recvmsg = tcp_bpf_recvmsg_parser; 556 } 557 558 static void tcp_bpf_check_v6_needs_rebuild(struct proto *ops) 559 { 560 if (unlikely(ops != smp_load_acquire(&tcpv6_prot_saved))) { 561 spin_lock_bh(&tcpv6_prot_lock); 562 if (likely(ops != tcpv6_prot_saved)) { 563 tcp_bpf_rebuild_protos(tcp_bpf_prots[TCP_BPF_IPV6], ops); 564 smp_store_release(&tcpv6_prot_saved, ops); 565 } 566 spin_unlock_bh(&tcpv6_prot_lock); 567 } 568 } 569 570 static int __init tcp_bpf_v4_build_proto(void) 571 { 572 tcp_bpf_rebuild_protos(tcp_bpf_prots[TCP_BPF_IPV4], &tcp_prot); 573 return 0; 574 } 575 late_initcall(tcp_bpf_v4_build_proto); 576 577 static int tcp_bpf_assert_proto_ops(struct proto *ops) 578 { 579 /* In order to avoid retpoline, we make assumptions when we call 580 * into ops if e.g. a psock is not present. Make sure they are 581 * indeed valid assumptions. 582 */ 583 return ops->recvmsg == tcp_recvmsg && 584 ops->sendmsg == tcp_sendmsg && 585 ops->sendpage == tcp_sendpage ? 0 : -ENOTSUPP; 586 } 587 588 int tcp_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore) 589 { 590 int family = sk->sk_family == AF_INET6 ? TCP_BPF_IPV6 : TCP_BPF_IPV4; 591 int config = psock->progs.msg_parser ? TCP_BPF_TX : TCP_BPF_BASE; 592 593 if (psock->progs.stream_verdict || psock->progs.skb_verdict) { 594 config = (config == TCP_BPF_TX) ? TCP_BPF_TXRX : TCP_BPF_RX; 595 } 596 597 if (restore) { 598 if (inet_csk_has_ulp(sk)) { 599 /* TLS does not have an unhash proto in SW cases, 600 * but we need to ensure we stop using the sock_map 601 * unhash routine because the associated psock is being 602 * removed. So use the original unhash handler. 603 */ 604 WRITE_ONCE(sk->sk_prot->unhash, psock->saved_unhash); 605 tcp_update_ulp(sk, psock->sk_proto, psock->saved_write_space); 606 } else { 607 sk->sk_write_space = psock->saved_write_space; 608 /* Pairs with lockless read in sk_clone_lock() */ 609 WRITE_ONCE(sk->sk_prot, psock->sk_proto); 610 } 611 return 0; 612 } 613 614 if (sk->sk_family == AF_INET6) { 615 if (tcp_bpf_assert_proto_ops(psock->sk_proto)) 616 return -EINVAL; 617 618 tcp_bpf_check_v6_needs_rebuild(psock->sk_proto); 619 } 620 621 /* Pairs with lockless read in sk_clone_lock() */ 622 WRITE_ONCE(sk->sk_prot, &tcp_bpf_prots[family][config]); 623 return 0; 624 } 625 EXPORT_SYMBOL_GPL(tcp_bpf_update_proto); 626 627 /* If a child got cloned from a listening socket that had tcp_bpf 628 * protocol callbacks installed, we need to restore the callbacks to 629 * the default ones because the child does not inherit the psock state 630 * that tcp_bpf callbacks expect. 631 */ 632 void tcp_bpf_clone(const struct sock *sk, struct sock *newsk) 633 { 634 int family = sk->sk_family == AF_INET6 ? TCP_BPF_IPV6 : TCP_BPF_IPV4; 635 struct proto *prot = newsk->sk_prot; 636 637 if (prot == &tcp_bpf_prots[family][TCP_BPF_BASE]) 638 newsk->sk_prot = sk->sk_prot_creator; 639 } 640 #endif /* CONFIG_BPF_SYSCALL */ 641