1 // SPDX-License-Identifier: GPL-2.0 2 #include <net/tcp.h> 3 #include <net/strparser.h> 4 #include <net/xfrm.h> 5 #include <net/esp.h> 6 #include <net/espintcp.h> 7 #include <linux/skmsg.h> 8 #include <net/inet_common.h> 9 #include <trace/events/sock.h> 10 #if IS_ENABLED(CONFIG_IPV6) 11 #include <net/ipv6_stubs.h> 12 #endif 13 14 static void handle_nonesp(struct espintcp_ctx *ctx, struct sk_buff *skb, 15 struct sock *sk) 16 { 17 if (atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf || 18 !sk_rmem_schedule(sk, skb, skb->truesize)) { 19 XFRM_INC_STATS(sock_net(sk), LINUX_MIB_XFRMINERROR); 20 kfree_skb(skb); 21 return; 22 } 23 24 skb_set_owner_r(skb, sk); 25 26 memset(skb->cb, 0, sizeof(skb->cb)); 27 skb_queue_tail(&ctx->ike_queue, skb); 28 ctx->saved_data_ready(sk); 29 } 30 31 static void handle_esp(struct sk_buff *skb, struct sock *sk) 32 { 33 struct tcp_skb_cb *tcp_cb = (struct tcp_skb_cb *)skb->cb; 34 35 skb_reset_transport_header(skb); 36 37 /* restore IP CB, we need at least IP6CB->nhoff */ 38 memmove(skb->cb, &tcp_cb->header, sizeof(tcp_cb->header)); 39 40 rcu_read_lock(); 41 skb->dev = dev_get_by_index_rcu(sock_net(sk), skb->skb_iif); 42 local_bh_disable(); 43 #if IS_ENABLED(CONFIG_IPV6) 44 if (sk->sk_family == AF_INET6) 45 ipv6_stub->xfrm6_rcv_encap(skb, IPPROTO_ESP, 0, TCP_ENCAP_ESPINTCP); 46 else 47 #endif 48 xfrm4_rcv_encap(skb, IPPROTO_ESP, 0, TCP_ENCAP_ESPINTCP); 49 local_bh_enable(); 50 rcu_read_unlock(); 51 } 52 53 static void espintcp_rcv(struct strparser *strp, struct sk_buff *skb) 54 { 55 struct espintcp_ctx *ctx = container_of(strp, struct espintcp_ctx, 56 strp); 57 struct strp_msg *rxm = strp_msg(skb); 58 int len = rxm->full_len - 2; 59 u32 nonesp_marker; 60 int err; 61 62 /* keepalive packet? */ 63 if (unlikely(len == 1)) { 64 u8 data; 65 66 err = skb_copy_bits(skb, rxm->offset + 2, &data, 1); 67 if (err < 0) { 68 XFRM_INC_STATS(sock_net(strp->sk), LINUX_MIB_XFRMINHDRERROR); 69 kfree_skb(skb); 70 return; 71 } 72 73 if (data == 0xff) { 74 kfree_skb(skb); 75 return; 76 } 77 } 78 79 /* drop other short messages */ 80 if (unlikely(len <= sizeof(nonesp_marker))) { 81 XFRM_INC_STATS(sock_net(strp->sk), LINUX_MIB_XFRMINHDRERROR); 82 kfree_skb(skb); 83 return; 84 } 85 86 err = skb_copy_bits(skb, rxm->offset + 2, &nonesp_marker, 87 sizeof(nonesp_marker)); 88 if (err < 0) { 89 XFRM_INC_STATS(sock_net(strp->sk), LINUX_MIB_XFRMINHDRERROR); 90 kfree_skb(skb); 91 return; 92 } 93 94 /* remove header, leave non-ESP marker/SPI */ 95 if (!pskb_pull(skb, rxm->offset + 2)) { 96 XFRM_INC_STATS(sock_net(strp->sk), LINUX_MIB_XFRMINERROR); 97 kfree_skb(skb); 98 return; 99 } 100 101 if (pskb_trim(skb, rxm->full_len - 2) != 0) { 102 XFRM_INC_STATS(sock_net(strp->sk), LINUX_MIB_XFRMINERROR); 103 kfree_skb(skb); 104 return; 105 } 106 107 if (nonesp_marker == 0) 108 handle_nonesp(ctx, skb, strp->sk); 109 else 110 handle_esp(skb, strp->sk); 111 } 112 113 static int espintcp_parse(struct strparser *strp, struct sk_buff *skb) 114 { 115 struct strp_msg *rxm = strp_msg(skb); 116 __be16 blen; 117 u16 len; 118 int err; 119 120 if (skb->len < rxm->offset + 2) 121 return 0; 122 123 err = skb_copy_bits(skb, rxm->offset, &blen, sizeof(blen)); 124 if (err < 0) 125 return err; 126 127 len = be16_to_cpu(blen); 128 if (len < 2) 129 return -EINVAL; 130 131 return len; 132 } 133 134 static int espintcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, 135 int flags, int *addr_len) 136 { 137 struct espintcp_ctx *ctx = espintcp_getctx(sk); 138 struct sk_buff *skb; 139 int err = 0; 140 int copied; 141 int off = 0; 142 143 skb = __skb_recv_datagram(sk, &ctx->ike_queue, flags, &off, &err); 144 if (!skb) { 145 if (err == -EAGAIN && sk->sk_shutdown & RCV_SHUTDOWN) 146 return 0; 147 return err; 148 } 149 150 copied = len; 151 if (copied > skb->len) 152 copied = skb->len; 153 else if (copied < skb->len) 154 msg->msg_flags |= MSG_TRUNC; 155 156 err = skb_copy_datagram_msg(skb, 0, msg, copied); 157 if (unlikely(err)) { 158 kfree_skb(skb); 159 return err; 160 } 161 162 if (flags & MSG_TRUNC) 163 copied = skb->len; 164 kfree_skb(skb); 165 return copied; 166 } 167 168 int espintcp_queue_out(struct sock *sk, struct sk_buff *skb) 169 { 170 struct espintcp_ctx *ctx = espintcp_getctx(sk); 171 172 if (skb_queue_len(&ctx->out_queue) >= READ_ONCE(netdev_max_backlog)) 173 return -ENOBUFS; 174 175 __skb_queue_tail(&ctx->out_queue, skb); 176 177 return 0; 178 } 179 EXPORT_SYMBOL_GPL(espintcp_queue_out); 180 181 /* espintcp length field is 2B and length includes the length field's size */ 182 #define MAX_ESPINTCP_MSG (((1 << 16) - 1) - 2) 183 184 static int espintcp_sendskb_locked(struct sock *sk, struct espintcp_msg *emsg, 185 int flags) 186 { 187 do { 188 int ret; 189 190 ret = skb_send_sock_locked(sk, emsg->skb, 191 emsg->offset, emsg->len); 192 if (ret < 0) 193 return ret; 194 195 emsg->len -= ret; 196 emsg->offset += ret; 197 } while (emsg->len > 0); 198 199 kfree_skb(emsg->skb); 200 memset(emsg, 0, sizeof(*emsg)); 201 202 return 0; 203 } 204 205 static int espintcp_sendskmsg_locked(struct sock *sk, 206 struct espintcp_msg *emsg, int flags) 207 { 208 struct msghdr msghdr = { 209 .msg_flags = flags | MSG_SPLICE_PAGES | MSG_MORE, 210 }; 211 struct sk_msg *skmsg = &emsg->skmsg; 212 bool more = flags & MSG_MORE; 213 struct scatterlist *sg; 214 int done = 0; 215 int ret; 216 217 sg = &skmsg->sg.data[skmsg->sg.start]; 218 do { 219 struct bio_vec bvec; 220 size_t size = sg->length - emsg->offset; 221 int offset = sg->offset + emsg->offset; 222 struct page *p; 223 224 emsg->offset = 0; 225 226 if (sg_is_last(sg) && !more) 227 msghdr.msg_flags &= ~MSG_MORE; 228 229 p = sg_page(sg); 230 retry: 231 bvec_set_page(&bvec, p, size, offset); 232 iov_iter_bvec(&msghdr.msg_iter, ITER_SOURCE, &bvec, 1, size); 233 ret = tcp_sendmsg_locked(sk, &msghdr, size); 234 if (ret < 0) { 235 emsg->offset = offset - sg->offset; 236 skmsg->sg.start += done; 237 return ret; 238 } 239 240 if (ret != size) { 241 offset += ret; 242 size -= ret; 243 goto retry; 244 } 245 246 done++; 247 put_page(p); 248 sk_mem_uncharge(sk, sg->length); 249 sg = sg_next(sg); 250 } while (sg); 251 252 memset(emsg, 0, sizeof(*emsg)); 253 254 return 0; 255 } 256 257 static int espintcp_push_msgs(struct sock *sk, int flags) 258 { 259 struct espintcp_ctx *ctx = espintcp_getctx(sk); 260 struct espintcp_msg *emsg = &ctx->partial; 261 int err; 262 263 if (!emsg->len) 264 return 0; 265 266 if (ctx->tx_running) 267 return -EAGAIN; 268 ctx->tx_running = 1; 269 270 if (emsg->skb) 271 err = espintcp_sendskb_locked(sk, emsg, flags); 272 else 273 err = espintcp_sendskmsg_locked(sk, emsg, flags); 274 if (err == -EAGAIN) { 275 ctx->tx_running = 0; 276 return flags & MSG_DONTWAIT ? -EAGAIN : 0; 277 } 278 if (!err) 279 memset(emsg, 0, sizeof(*emsg)); 280 281 ctx->tx_running = 0; 282 283 return err; 284 } 285 286 int espintcp_push_skb(struct sock *sk, struct sk_buff *skb) 287 { 288 struct espintcp_ctx *ctx = espintcp_getctx(sk); 289 struct espintcp_msg *emsg = &ctx->partial; 290 unsigned int len; 291 int offset; 292 293 if (sk->sk_state != TCP_ESTABLISHED) { 294 kfree_skb(skb); 295 return -ECONNRESET; 296 } 297 298 offset = skb_transport_offset(skb); 299 len = skb->len - offset; 300 301 espintcp_push_msgs(sk, 0); 302 303 if (emsg->len) { 304 kfree_skb(skb); 305 return -ENOBUFS; 306 } 307 308 skb_set_owner_w(skb, sk); 309 310 emsg->offset = offset; 311 emsg->len = len; 312 emsg->skb = skb; 313 314 espintcp_push_msgs(sk, 0); 315 316 return 0; 317 } 318 EXPORT_SYMBOL_GPL(espintcp_push_skb); 319 320 static int espintcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size) 321 { 322 long timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT); 323 struct espintcp_ctx *ctx = espintcp_getctx(sk); 324 struct espintcp_msg *emsg = &ctx->partial; 325 struct iov_iter pfx_iter; 326 struct kvec pfx_iov = {}; 327 size_t msglen = size + 2; 328 char buf[2] = {0}; 329 int err, end; 330 331 if (msg->msg_flags & ~MSG_DONTWAIT) 332 return -EOPNOTSUPP; 333 334 if (size > MAX_ESPINTCP_MSG) 335 return -EMSGSIZE; 336 337 if (msg->msg_controllen) 338 return -EOPNOTSUPP; 339 340 lock_sock(sk); 341 342 err = espintcp_push_msgs(sk, msg->msg_flags & MSG_DONTWAIT); 343 if (err < 0) { 344 if (err != -EAGAIN || !(msg->msg_flags & MSG_DONTWAIT)) 345 err = -ENOBUFS; 346 goto unlock; 347 } 348 349 sk_msg_init(&emsg->skmsg); 350 while (1) { 351 /* only -ENOMEM is possible since we don't coalesce */ 352 err = sk_msg_alloc(sk, &emsg->skmsg, msglen, 0); 353 if (!err) 354 break; 355 356 err = sk_stream_wait_memory(sk, &timeo); 357 if (err) 358 goto fail; 359 } 360 361 *((__be16 *)buf) = cpu_to_be16(msglen); 362 pfx_iov.iov_base = buf; 363 pfx_iov.iov_len = sizeof(buf); 364 iov_iter_kvec(&pfx_iter, ITER_SOURCE, &pfx_iov, 1, pfx_iov.iov_len); 365 366 err = sk_msg_memcopy_from_iter(sk, &pfx_iter, &emsg->skmsg, 367 pfx_iov.iov_len); 368 if (err < 0) 369 goto fail; 370 371 err = sk_msg_memcopy_from_iter(sk, &msg->msg_iter, &emsg->skmsg, size); 372 if (err < 0) 373 goto fail; 374 375 end = emsg->skmsg.sg.end; 376 emsg->len = size; 377 sk_msg_iter_var_prev(end); 378 sg_mark_end(sk_msg_elem(&emsg->skmsg, end)); 379 380 tcp_rate_check_app_limited(sk); 381 382 err = espintcp_push_msgs(sk, msg->msg_flags & MSG_DONTWAIT); 383 /* this message could be partially sent, keep it */ 384 385 release_sock(sk); 386 387 return size; 388 389 fail: 390 sk_msg_free(sk, &emsg->skmsg); 391 memset(emsg, 0, sizeof(*emsg)); 392 unlock: 393 release_sock(sk); 394 return err; 395 } 396 397 static struct proto espintcp_prot __ro_after_init; 398 static struct proto_ops espintcp_ops __ro_after_init; 399 static struct proto espintcp6_prot; 400 static struct proto_ops espintcp6_ops; 401 static DEFINE_MUTEX(tcpv6_prot_mutex); 402 403 static void espintcp_data_ready(struct sock *sk) 404 { 405 struct espintcp_ctx *ctx = espintcp_getctx(sk); 406 407 trace_sk_data_ready(sk); 408 409 strp_data_ready(&ctx->strp); 410 } 411 412 static void espintcp_tx_work(struct work_struct *work) 413 { 414 struct espintcp_ctx *ctx = container_of(work, 415 struct espintcp_ctx, work); 416 struct sock *sk = ctx->strp.sk; 417 418 lock_sock(sk); 419 if (!ctx->tx_running) 420 espintcp_push_msgs(sk, 0); 421 release_sock(sk); 422 } 423 424 static void espintcp_write_space(struct sock *sk) 425 { 426 struct espintcp_ctx *ctx = espintcp_getctx(sk); 427 428 schedule_work(&ctx->work); 429 ctx->saved_write_space(sk); 430 } 431 432 static void espintcp_destruct(struct sock *sk) 433 { 434 struct espintcp_ctx *ctx = espintcp_getctx(sk); 435 436 ctx->saved_destruct(sk); 437 kfree(ctx); 438 } 439 440 bool tcp_is_ulp_esp(struct sock *sk) 441 { 442 return sk->sk_prot == &espintcp_prot || sk->sk_prot == &espintcp6_prot; 443 } 444 EXPORT_SYMBOL_GPL(tcp_is_ulp_esp); 445 446 static void build_protos(struct proto *espintcp_prot, 447 struct proto_ops *espintcp_ops, 448 const struct proto *orig_prot, 449 const struct proto_ops *orig_ops); 450 static int espintcp_init_sk(struct sock *sk) 451 { 452 struct inet_connection_sock *icsk = inet_csk(sk); 453 struct strp_callbacks cb = { 454 .rcv_msg = espintcp_rcv, 455 .parse_msg = espintcp_parse, 456 }; 457 struct espintcp_ctx *ctx; 458 int err; 459 460 /* sockmap is not compatible with espintcp */ 461 if (sk->sk_user_data) 462 return -EBUSY; 463 464 ctx = kzalloc(sizeof(*ctx), GFP_KERNEL); 465 if (!ctx) 466 return -ENOMEM; 467 468 err = strp_init(&ctx->strp, sk, &cb); 469 if (err) 470 goto free; 471 472 __sk_dst_reset(sk); 473 474 strp_check_rcv(&ctx->strp); 475 skb_queue_head_init(&ctx->ike_queue); 476 skb_queue_head_init(&ctx->out_queue); 477 478 if (sk->sk_family == AF_INET) { 479 sk->sk_prot = &espintcp_prot; 480 sk->sk_socket->ops = &espintcp_ops; 481 } else { 482 mutex_lock(&tcpv6_prot_mutex); 483 if (!espintcp6_prot.recvmsg) 484 build_protos(&espintcp6_prot, &espintcp6_ops, sk->sk_prot, sk->sk_socket->ops); 485 mutex_unlock(&tcpv6_prot_mutex); 486 487 sk->sk_prot = &espintcp6_prot; 488 sk->sk_socket->ops = &espintcp6_ops; 489 } 490 ctx->saved_data_ready = sk->sk_data_ready; 491 ctx->saved_write_space = sk->sk_write_space; 492 ctx->saved_destruct = sk->sk_destruct; 493 sk->sk_data_ready = espintcp_data_ready; 494 sk->sk_write_space = espintcp_write_space; 495 sk->sk_destruct = espintcp_destruct; 496 rcu_assign_pointer(icsk->icsk_ulp_data, ctx); 497 INIT_WORK(&ctx->work, espintcp_tx_work); 498 499 /* avoid using task_frag */ 500 sk->sk_allocation = GFP_ATOMIC; 501 sk->sk_use_task_frag = false; 502 503 return 0; 504 505 free: 506 kfree(ctx); 507 return err; 508 } 509 510 static void espintcp_release(struct sock *sk) 511 { 512 struct espintcp_ctx *ctx = espintcp_getctx(sk); 513 struct sk_buff_head queue; 514 struct sk_buff *skb; 515 516 __skb_queue_head_init(&queue); 517 skb_queue_splice_init(&ctx->out_queue, &queue); 518 519 while ((skb = __skb_dequeue(&queue))) 520 espintcp_push_skb(sk, skb); 521 522 tcp_release_cb(sk); 523 } 524 525 static void espintcp_close(struct sock *sk, long timeout) 526 { 527 struct espintcp_ctx *ctx = espintcp_getctx(sk); 528 struct espintcp_msg *emsg = &ctx->partial; 529 530 strp_stop(&ctx->strp); 531 532 sk->sk_prot = &tcp_prot; 533 barrier(); 534 535 cancel_work_sync(&ctx->work); 536 strp_done(&ctx->strp); 537 538 skb_queue_purge(&ctx->out_queue); 539 skb_queue_purge(&ctx->ike_queue); 540 541 if (emsg->len) { 542 if (emsg->skb) 543 kfree_skb(emsg->skb); 544 else 545 sk_msg_free(sk, &emsg->skmsg); 546 } 547 548 tcp_close(sk, timeout); 549 } 550 551 static __poll_t espintcp_poll(struct file *file, struct socket *sock, 552 poll_table *wait) 553 { 554 __poll_t mask = datagram_poll(file, sock, wait); 555 struct sock *sk = sock->sk; 556 struct espintcp_ctx *ctx = espintcp_getctx(sk); 557 558 if (!skb_queue_empty(&ctx->ike_queue)) 559 mask |= EPOLLIN | EPOLLRDNORM; 560 561 return mask; 562 } 563 564 static void build_protos(struct proto *espintcp_prot, 565 struct proto_ops *espintcp_ops, 566 const struct proto *orig_prot, 567 const struct proto_ops *orig_ops) 568 { 569 memcpy(espintcp_prot, orig_prot, sizeof(struct proto)); 570 memcpy(espintcp_ops, orig_ops, sizeof(struct proto_ops)); 571 espintcp_prot->sendmsg = espintcp_sendmsg; 572 espintcp_prot->recvmsg = espintcp_recvmsg; 573 espintcp_prot->close = espintcp_close; 574 espintcp_prot->release_cb = espintcp_release; 575 espintcp_ops->poll = espintcp_poll; 576 } 577 578 static struct tcp_ulp_ops espintcp_ulp __read_mostly = { 579 .name = "espintcp", 580 .owner = THIS_MODULE, 581 .init = espintcp_init_sk, 582 }; 583 584 void __init espintcp_init(void) 585 { 586 build_protos(&espintcp_prot, &espintcp_ops, &tcp_prot, &inet_stream_ops); 587 588 tcp_register_ulp(&espintcp_ulp); 589 } 590