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