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 #include <net/hotdata.h> 14 15 static void handle_nonesp(struct espintcp_ctx *ctx, struct sk_buff *skb, 16 struct sock *sk) 17 { 18 if (atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf || 19 !sk_rmem_schedule(sk, skb, skb->truesize)) { 20 XFRM_INC_STATS(sock_net(sk), LINUX_MIB_XFRMINERROR); 21 kfree_skb(skb); 22 return; 23 } 24 25 skb_set_owner_r(skb, sk); 26 27 memset(skb->cb, 0, sizeof(skb->cb)); 28 skb_queue_tail(&ctx->ike_queue, skb); 29 ctx->saved_data_ready(sk); 30 } 31 32 static void handle_esp(struct sk_buff *skb, struct sock *sk) 33 { 34 struct tcp_skb_cb *tcp_cb = (struct tcp_skb_cb *)skb->cb; 35 36 skb_reset_transport_header(skb); 37 38 /* restore IP CB, we need at least IP6CB->nhoff */ 39 memmove(skb->cb, &tcp_cb->header, sizeof(tcp_cb->header)); 40 41 rcu_read_lock(); 42 skb->dev = dev_get_by_index_rcu(sock_net(sk), skb->skb_iif); 43 local_bh_disable(); 44 #if IS_ENABLED(CONFIG_IPV6) 45 if (sk->sk_family == AF_INET6) 46 ipv6_stub->xfrm6_rcv_encap(skb, IPPROTO_ESP, 0, TCP_ENCAP_ESPINTCP); 47 else 48 #endif 49 xfrm4_rcv_encap(skb, IPPROTO_ESP, 0, TCP_ENCAP_ESPINTCP); 50 local_bh_enable(); 51 rcu_read_unlock(); 52 } 53 54 static void espintcp_rcv(struct strparser *strp, struct sk_buff *skb) 55 { 56 struct espintcp_ctx *ctx = container_of(strp, struct espintcp_ctx, 57 strp); 58 struct strp_msg *rxm = strp_msg(skb); 59 int len = rxm->full_len - 2; 60 u32 nonesp_marker; 61 int err; 62 63 /* keepalive packet? */ 64 if (unlikely(len == 1)) { 65 u8 data; 66 67 err = skb_copy_bits(skb, rxm->offset + 2, &data, 1); 68 if (err < 0) { 69 XFRM_INC_STATS(sock_net(strp->sk), LINUX_MIB_XFRMINHDRERROR); 70 kfree_skb(skb); 71 return; 72 } 73 74 if (data == 0xff) { 75 kfree_skb(skb); 76 return; 77 } 78 } 79 80 /* drop other short messages */ 81 if (unlikely(len <= sizeof(nonesp_marker))) { 82 XFRM_INC_STATS(sock_net(strp->sk), LINUX_MIB_XFRMINHDRERROR); 83 kfree_skb(skb); 84 return; 85 } 86 87 err = skb_copy_bits(skb, rxm->offset + 2, &nonesp_marker, 88 sizeof(nonesp_marker)); 89 if (err < 0) { 90 XFRM_INC_STATS(sock_net(strp->sk), LINUX_MIB_XFRMINHDRERROR); 91 kfree_skb(skb); 92 return; 93 } 94 95 /* remove header, leave non-ESP marker/SPI */ 96 if (!pskb_pull(skb, rxm->offset + 2)) { 97 XFRM_INC_STATS(sock_net(strp->sk), LINUX_MIB_XFRMINERROR); 98 kfree_skb(skb); 99 return; 100 } 101 102 if (pskb_trim(skb, rxm->full_len - 2) != 0) { 103 XFRM_INC_STATS(sock_net(strp->sk), LINUX_MIB_XFRMINERROR); 104 kfree_skb(skb); 105 return; 106 } 107 108 if (nonesp_marker == 0) 109 handle_nonesp(ctx, skb, strp->sk); 110 else 111 handle_esp(skb, strp->sk); 112 } 113 114 static int espintcp_parse(struct strparser *strp, struct sk_buff *skb) 115 { 116 struct strp_msg *rxm = strp_msg(skb); 117 __be16 blen; 118 u16 len; 119 int err; 120 121 if (skb->len < rxm->offset + 2) 122 return 0; 123 124 err = skb_copy_bits(skb, rxm->offset, &blen, sizeof(blen)); 125 if (err < 0) 126 return err; 127 128 len = be16_to_cpu(blen); 129 if (len < 2) 130 return -EINVAL; 131 132 return len; 133 } 134 135 static int espintcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, 136 int flags, int *addr_len) 137 { 138 struct espintcp_ctx *ctx = espintcp_getctx(sk); 139 struct sk_buff *skb; 140 int err = 0; 141 int copied; 142 int off = 0; 143 144 skb = __skb_recv_datagram(sk, &ctx->ike_queue, flags, &off, &err); 145 if (!skb) { 146 if (err == -EAGAIN && sk->sk_shutdown & RCV_SHUTDOWN) 147 return 0; 148 return err; 149 } 150 151 copied = len; 152 if (copied > skb->len) 153 copied = skb->len; 154 else if (copied < skb->len) 155 msg->msg_flags |= MSG_TRUNC; 156 157 err = skb_copy_datagram_msg(skb, 0, msg, copied); 158 if (unlikely(err)) { 159 kfree_skb(skb); 160 return err; 161 } 162 163 if (flags & MSG_TRUNC) 164 copied = skb->len; 165 kfree_skb(skb); 166 return copied; 167 } 168 169 int espintcp_queue_out(struct sock *sk, struct sk_buff *skb) 170 { 171 struct espintcp_ctx *ctx = espintcp_getctx(sk); 172 173 if (skb_queue_len(&ctx->out_queue) >= 174 READ_ONCE(net_hotdata.max_backlog)) 175 return -ENOBUFS; 176 177 __skb_queue_tail(&ctx->out_queue, skb); 178 179 return 0; 180 } 181 EXPORT_SYMBOL_GPL(espintcp_queue_out); 182 183 /* espintcp length field is 2B and length includes the length field's size */ 184 #define MAX_ESPINTCP_MSG (((1 << 16) - 1) - 2) 185 186 static int espintcp_sendskb_locked(struct sock *sk, struct espintcp_msg *emsg, 187 int flags) 188 { 189 do { 190 int ret; 191 192 ret = skb_send_sock_locked(sk, emsg->skb, 193 emsg->offset, emsg->len); 194 if (ret < 0) 195 return ret; 196 197 emsg->len -= ret; 198 emsg->offset += ret; 199 } while (emsg->len > 0); 200 201 kfree_skb(emsg->skb); 202 memset(emsg, 0, sizeof(*emsg)); 203 204 return 0; 205 } 206 207 static int espintcp_sendskmsg_locked(struct sock *sk, 208 struct espintcp_msg *emsg, int flags) 209 { 210 struct msghdr msghdr = { 211 .msg_flags = flags | MSG_SPLICE_PAGES | MSG_MORE, 212 }; 213 struct sk_msg *skmsg = &emsg->skmsg; 214 bool more = flags & MSG_MORE; 215 struct scatterlist *sg; 216 int done = 0; 217 int ret; 218 219 sg = &skmsg->sg.data[skmsg->sg.start]; 220 do { 221 struct bio_vec bvec; 222 size_t size = sg->length - emsg->offset; 223 int offset = sg->offset + emsg->offset; 224 struct page *p; 225 226 emsg->offset = 0; 227 228 if (sg_is_last(sg) && !more) 229 msghdr.msg_flags &= ~MSG_MORE; 230 231 p = sg_page(sg); 232 retry: 233 bvec_set_page(&bvec, p, size, offset); 234 iov_iter_bvec(&msghdr.msg_iter, ITER_SOURCE, &bvec, 1, size); 235 ret = tcp_sendmsg_locked(sk, &msghdr, size); 236 if (ret < 0) { 237 emsg->offset = offset - sg->offset; 238 skmsg->sg.start += done; 239 return ret; 240 } 241 242 if (ret != size) { 243 offset += ret; 244 size -= ret; 245 goto retry; 246 } 247 248 done++; 249 put_page(p); 250 sk_mem_uncharge(sk, sg->length); 251 sg = sg_next(sg); 252 } while (sg); 253 254 memset(emsg, 0, sizeof(*emsg)); 255 256 return 0; 257 } 258 259 static int espintcp_push_msgs(struct sock *sk, int flags) 260 { 261 struct espintcp_ctx *ctx = espintcp_getctx(sk); 262 struct espintcp_msg *emsg = &ctx->partial; 263 int err; 264 265 if (!emsg->len) 266 return 0; 267 268 if (ctx->tx_running) 269 return -EAGAIN; 270 ctx->tx_running = 1; 271 272 if (emsg->skb) 273 err = espintcp_sendskb_locked(sk, emsg, flags); 274 else 275 err = espintcp_sendskmsg_locked(sk, emsg, flags); 276 if (err == -EAGAIN) { 277 ctx->tx_running = 0; 278 return flags & MSG_DONTWAIT ? -EAGAIN : 0; 279 } 280 if (!err) 281 memset(emsg, 0, sizeof(*emsg)); 282 283 ctx->tx_running = 0; 284 285 return err; 286 } 287 288 int espintcp_push_skb(struct sock *sk, struct sk_buff *skb) 289 { 290 struct espintcp_ctx *ctx = espintcp_getctx(sk); 291 struct espintcp_msg *emsg = &ctx->partial; 292 unsigned int len; 293 int offset; 294 295 if (sk->sk_state != TCP_ESTABLISHED) { 296 kfree_skb(skb); 297 return -ECONNRESET; 298 } 299 300 offset = skb_transport_offset(skb); 301 len = skb->len - offset; 302 303 espintcp_push_msgs(sk, 0); 304 305 if (emsg->len) { 306 kfree_skb(skb); 307 return -ENOBUFS; 308 } 309 310 skb_set_owner_w(skb, sk); 311 312 emsg->offset = offset; 313 emsg->len = len; 314 emsg->skb = skb; 315 316 espintcp_push_msgs(sk, 0); 317 318 return 0; 319 } 320 EXPORT_SYMBOL_GPL(espintcp_push_skb); 321 322 static int espintcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size) 323 { 324 long timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT); 325 struct espintcp_ctx *ctx = espintcp_getctx(sk); 326 struct espintcp_msg *emsg = &ctx->partial; 327 struct iov_iter pfx_iter; 328 struct kvec pfx_iov = {}; 329 size_t msglen = size + 2; 330 char buf[2] = {0}; 331 int err, end; 332 333 if (msg->msg_flags & ~MSG_DONTWAIT) 334 return -EOPNOTSUPP; 335 336 if (size > MAX_ESPINTCP_MSG) 337 return -EMSGSIZE; 338 339 if (msg->msg_controllen) 340 return -EOPNOTSUPP; 341 342 lock_sock(sk); 343 344 err = espintcp_push_msgs(sk, msg->msg_flags & MSG_DONTWAIT); 345 if (err < 0) { 346 if (err != -EAGAIN || !(msg->msg_flags & MSG_DONTWAIT)) 347 err = -ENOBUFS; 348 goto unlock; 349 } 350 351 sk_msg_init(&emsg->skmsg); 352 while (1) { 353 /* only -ENOMEM is possible since we don't coalesce */ 354 err = sk_msg_alloc(sk, &emsg->skmsg, msglen, 0); 355 if (!err) 356 break; 357 358 err = sk_stream_wait_memory(sk, &timeo); 359 if (err) 360 goto fail; 361 } 362 363 *((__be16 *)buf) = cpu_to_be16(msglen); 364 pfx_iov.iov_base = buf; 365 pfx_iov.iov_len = sizeof(buf); 366 iov_iter_kvec(&pfx_iter, ITER_SOURCE, &pfx_iov, 1, pfx_iov.iov_len); 367 368 err = sk_msg_memcopy_from_iter(sk, &pfx_iter, &emsg->skmsg, 369 pfx_iov.iov_len); 370 if (err < 0) 371 goto fail; 372 373 err = sk_msg_memcopy_from_iter(sk, &msg->msg_iter, &emsg->skmsg, size); 374 if (err < 0) 375 goto fail; 376 377 end = emsg->skmsg.sg.end; 378 emsg->len = size; 379 sk_msg_iter_var_prev(end); 380 sg_mark_end(sk_msg_elem(&emsg->skmsg, end)); 381 382 tcp_rate_check_app_limited(sk); 383 384 err = espintcp_push_msgs(sk, msg->msg_flags & MSG_DONTWAIT); 385 /* this message could be partially sent, keep it */ 386 387 release_sock(sk); 388 389 return size; 390 391 fail: 392 sk_msg_free(sk, &emsg->skmsg); 393 memset(emsg, 0, sizeof(*emsg)); 394 unlock: 395 release_sock(sk); 396 return err; 397 } 398 399 static struct proto espintcp_prot __ro_after_init; 400 static struct proto_ops espintcp_ops __ro_after_init; 401 static struct proto espintcp6_prot; 402 static struct proto_ops espintcp6_ops; 403 static DEFINE_MUTEX(tcpv6_prot_mutex); 404 405 static void espintcp_data_ready(struct sock *sk) 406 { 407 struct espintcp_ctx *ctx = espintcp_getctx(sk); 408 409 trace_sk_data_ready(sk); 410 411 strp_data_ready(&ctx->strp); 412 } 413 414 static void espintcp_tx_work(struct work_struct *work) 415 { 416 struct espintcp_ctx *ctx = container_of(work, 417 struct espintcp_ctx, work); 418 struct sock *sk = ctx->strp.sk; 419 420 lock_sock(sk); 421 if (!ctx->tx_running) 422 espintcp_push_msgs(sk, 0); 423 release_sock(sk); 424 } 425 426 static void espintcp_write_space(struct sock *sk) 427 { 428 struct espintcp_ctx *ctx = espintcp_getctx(sk); 429 430 schedule_work(&ctx->work); 431 ctx->saved_write_space(sk); 432 } 433 434 static void espintcp_destruct(struct sock *sk) 435 { 436 struct espintcp_ctx *ctx = espintcp_getctx(sk); 437 438 ctx->saved_destruct(sk); 439 kfree(ctx); 440 } 441 442 bool tcp_is_ulp_esp(struct sock *sk) 443 { 444 return sk->sk_prot == &espintcp_prot || sk->sk_prot == &espintcp6_prot; 445 } 446 EXPORT_SYMBOL_GPL(tcp_is_ulp_esp); 447 448 static void build_protos(struct proto *espintcp_prot, 449 struct proto_ops *espintcp_ops, 450 const struct proto *orig_prot, 451 const struct proto_ops *orig_ops); 452 static int espintcp_init_sk(struct sock *sk) 453 { 454 struct inet_connection_sock *icsk = inet_csk(sk); 455 struct strp_callbacks cb = { 456 .rcv_msg = espintcp_rcv, 457 .parse_msg = espintcp_parse, 458 }; 459 struct espintcp_ctx *ctx; 460 int err; 461 462 /* sockmap is not compatible with espintcp */ 463 if (sk->sk_user_data) 464 return -EBUSY; 465 466 ctx = kzalloc(sizeof(*ctx), GFP_KERNEL); 467 if (!ctx) 468 return -ENOMEM; 469 470 err = strp_init(&ctx->strp, sk, &cb); 471 if (err) 472 goto free; 473 474 __sk_dst_reset(sk); 475 476 strp_check_rcv(&ctx->strp); 477 skb_queue_head_init(&ctx->ike_queue); 478 skb_queue_head_init(&ctx->out_queue); 479 480 if (sk->sk_family == AF_INET) { 481 sk->sk_prot = &espintcp_prot; 482 sk->sk_socket->ops = &espintcp_ops; 483 } else { 484 mutex_lock(&tcpv6_prot_mutex); 485 if (!espintcp6_prot.recvmsg) 486 build_protos(&espintcp6_prot, &espintcp6_ops, sk->sk_prot, sk->sk_socket->ops); 487 mutex_unlock(&tcpv6_prot_mutex); 488 489 sk->sk_prot = &espintcp6_prot; 490 sk->sk_socket->ops = &espintcp6_ops; 491 } 492 ctx->saved_data_ready = sk->sk_data_ready; 493 ctx->saved_write_space = sk->sk_write_space; 494 ctx->saved_destruct = sk->sk_destruct; 495 sk->sk_data_ready = espintcp_data_ready; 496 sk->sk_write_space = espintcp_write_space; 497 sk->sk_destruct = espintcp_destruct; 498 rcu_assign_pointer(icsk->icsk_ulp_data, ctx); 499 INIT_WORK(&ctx->work, espintcp_tx_work); 500 501 /* avoid using task_frag */ 502 sk->sk_allocation = GFP_ATOMIC; 503 sk->sk_use_task_frag = false; 504 505 return 0; 506 507 free: 508 kfree(ctx); 509 return err; 510 } 511 512 static void espintcp_release(struct sock *sk) 513 { 514 struct espintcp_ctx *ctx = espintcp_getctx(sk); 515 struct sk_buff_head queue; 516 struct sk_buff *skb; 517 518 __skb_queue_head_init(&queue); 519 skb_queue_splice_init(&ctx->out_queue, &queue); 520 521 while ((skb = __skb_dequeue(&queue))) 522 espintcp_push_skb(sk, skb); 523 524 tcp_release_cb(sk); 525 } 526 527 static void espintcp_close(struct sock *sk, long timeout) 528 { 529 struct espintcp_ctx *ctx = espintcp_getctx(sk); 530 struct espintcp_msg *emsg = &ctx->partial; 531 532 strp_stop(&ctx->strp); 533 534 sk->sk_prot = &tcp_prot; 535 barrier(); 536 537 cancel_work_sync(&ctx->work); 538 strp_done(&ctx->strp); 539 540 skb_queue_purge(&ctx->out_queue); 541 skb_queue_purge(&ctx->ike_queue); 542 543 if (emsg->len) { 544 if (emsg->skb) 545 kfree_skb(emsg->skb); 546 else 547 sk_msg_free(sk, &emsg->skmsg); 548 } 549 550 tcp_close(sk, timeout); 551 } 552 553 static __poll_t espintcp_poll(struct file *file, struct socket *sock, 554 poll_table *wait) 555 { 556 __poll_t mask = datagram_poll(file, sock, wait); 557 struct sock *sk = sock->sk; 558 struct espintcp_ctx *ctx = espintcp_getctx(sk); 559 560 if (!skb_queue_empty(&ctx->ike_queue)) 561 mask |= EPOLLIN | EPOLLRDNORM; 562 563 return mask; 564 } 565 566 static void build_protos(struct proto *espintcp_prot, 567 struct proto_ops *espintcp_ops, 568 const struct proto *orig_prot, 569 const struct proto_ops *orig_ops) 570 { 571 memcpy(espintcp_prot, orig_prot, sizeof(struct proto)); 572 memcpy(espintcp_ops, orig_ops, sizeof(struct proto_ops)); 573 espintcp_prot->sendmsg = espintcp_sendmsg; 574 espintcp_prot->recvmsg = espintcp_recvmsg; 575 espintcp_prot->close = espintcp_close; 576 espintcp_prot->release_cb = espintcp_release; 577 espintcp_ops->poll = espintcp_poll; 578 } 579 580 static struct tcp_ulp_ops espintcp_ulp __read_mostly = { 581 .name = "espintcp", 582 .owner = THIS_MODULE, 583 .init = espintcp_init_sk, 584 }; 585 586 void __init espintcp_init(void) 587 { 588 build_protos(&espintcp_prot, &espintcp_ops, &tcp_prot, &inet_stream_ops); 589 590 tcp_register_ulp(&espintcp_ulp); 591 } 592