1 /* 2 * Kernel Connection Multiplexor 3 * 4 * Copyright (c) 2016 Tom Herbert <tom@herbertland.com> 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 8 * as published by the Free Software Foundation. 9 */ 10 11 #include <linux/bpf.h> 12 #include <linux/errno.h> 13 #include <linux/errqueue.h> 14 #include <linux/file.h> 15 #include <linux/in.h> 16 #include <linux/kernel.h> 17 #include <linux/module.h> 18 #include <linux/net.h> 19 #include <linux/netdevice.h> 20 #include <linux/poll.h> 21 #include <linux/rculist.h> 22 #include <linux/skbuff.h> 23 #include <linux/socket.h> 24 #include <linux/uaccess.h> 25 #include <linux/workqueue.h> 26 #include <net/kcm.h> 27 #include <net/netns/generic.h> 28 #include <net/sock.h> 29 #include <uapi/linux/kcm.h> 30 31 unsigned int kcm_net_id; 32 33 static struct kmem_cache *kcm_psockp __read_mostly; 34 static struct kmem_cache *kcm_muxp __read_mostly; 35 static struct workqueue_struct *kcm_wq; 36 37 static inline struct kcm_sock *kcm_sk(const struct sock *sk) 38 { 39 return (struct kcm_sock *)sk; 40 } 41 42 static inline struct kcm_tx_msg *kcm_tx_msg(struct sk_buff *skb) 43 { 44 return (struct kcm_tx_msg *)skb->cb; 45 } 46 47 static void report_csk_error(struct sock *csk, int err) 48 { 49 csk->sk_err = EPIPE; 50 csk->sk_error_report(csk); 51 } 52 53 static void kcm_abort_tx_psock(struct kcm_psock *psock, int err, 54 bool wakeup_kcm) 55 { 56 struct sock *csk = psock->sk; 57 struct kcm_mux *mux = psock->mux; 58 59 /* Unrecoverable error in transmit */ 60 61 spin_lock_bh(&mux->lock); 62 63 if (psock->tx_stopped) { 64 spin_unlock_bh(&mux->lock); 65 return; 66 } 67 68 psock->tx_stopped = 1; 69 KCM_STATS_INCR(psock->stats.tx_aborts); 70 71 if (!psock->tx_kcm) { 72 /* Take off psocks_avail list */ 73 list_del(&psock->psock_avail_list); 74 } else if (wakeup_kcm) { 75 /* In this case psock is being aborted while outside of 76 * write_msgs and psock is reserved. Schedule tx_work 77 * to handle the failure there. Need to commit tx_stopped 78 * before queuing work. 79 */ 80 smp_mb(); 81 82 queue_work(kcm_wq, &psock->tx_kcm->tx_work); 83 } 84 85 spin_unlock_bh(&mux->lock); 86 87 /* Report error on lower socket */ 88 report_csk_error(csk, err); 89 } 90 91 /* RX mux lock held. */ 92 static void kcm_update_rx_mux_stats(struct kcm_mux *mux, 93 struct kcm_psock *psock) 94 { 95 STRP_STATS_ADD(mux->stats.rx_bytes, 96 psock->strp.stats.rx_bytes - 97 psock->saved_rx_bytes); 98 mux->stats.rx_msgs += 99 psock->strp.stats.rx_msgs - psock->saved_rx_msgs; 100 psock->saved_rx_msgs = psock->strp.stats.rx_msgs; 101 psock->saved_rx_bytes = psock->strp.stats.rx_bytes; 102 } 103 104 static void kcm_update_tx_mux_stats(struct kcm_mux *mux, 105 struct kcm_psock *psock) 106 { 107 KCM_STATS_ADD(mux->stats.tx_bytes, 108 psock->stats.tx_bytes - psock->saved_tx_bytes); 109 mux->stats.tx_msgs += 110 psock->stats.tx_msgs - psock->saved_tx_msgs; 111 psock->saved_tx_msgs = psock->stats.tx_msgs; 112 psock->saved_tx_bytes = psock->stats.tx_bytes; 113 } 114 115 static int kcm_queue_rcv_skb(struct sock *sk, struct sk_buff *skb); 116 117 /* KCM is ready to receive messages on its queue-- either the KCM is new or 118 * has become unblocked after being blocked on full socket buffer. Queue any 119 * pending ready messages on a psock. RX mux lock held. 120 */ 121 static void kcm_rcv_ready(struct kcm_sock *kcm) 122 { 123 struct kcm_mux *mux = kcm->mux; 124 struct kcm_psock *psock; 125 struct sk_buff *skb; 126 127 if (unlikely(kcm->rx_wait || kcm->rx_psock || kcm->rx_disabled)) 128 return; 129 130 while (unlikely((skb = __skb_dequeue(&mux->rx_hold_queue)))) { 131 if (kcm_queue_rcv_skb(&kcm->sk, skb)) { 132 /* Assuming buffer limit has been reached */ 133 skb_queue_head(&mux->rx_hold_queue, skb); 134 WARN_ON(!sk_rmem_alloc_get(&kcm->sk)); 135 return; 136 } 137 } 138 139 while (!list_empty(&mux->psocks_ready)) { 140 psock = list_first_entry(&mux->psocks_ready, struct kcm_psock, 141 psock_ready_list); 142 143 if (kcm_queue_rcv_skb(&kcm->sk, psock->ready_rx_msg)) { 144 /* Assuming buffer limit has been reached */ 145 WARN_ON(!sk_rmem_alloc_get(&kcm->sk)); 146 return; 147 } 148 149 /* Consumed the ready message on the psock. Schedule rx_work to 150 * get more messages. 151 */ 152 list_del(&psock->psock_ready_list); 153 psock->ready_rx_msg = NULL; 154 /* Commit clearing of ready_rx_msg for queuing work */ 155 smp_mb(); 156 157 strp_unpause(&psock->strp); 158 strp_check_rcv(&psock->strp); 159 } 160 161 /* Buffer limit is okay now, add to ready list */ 162 list_add_tail(&kcm->wait_rx_list, 163 &kcm->mux->kcm_rx_waiters); 164 kcm->rx_wait = true; 165 } 166 167 static void kcm_rfree(struct sk_buff *skb) 168 { 169 struct sock *sk = skb->sk; 170 struct kcm_sock *kcm = kcm_sk(sk); 171 struct kcm_mux *mux = kcm->mux; 172 unsigned int len = skb->truesize; 173 174 sk_mem_uncharge(sk, len); 175 atomic_sub(len, &sk->sk_rmem_alloc); 176 177 /* For reading rx_wait and rx_psock without holding lock */ 178 smp_mb__after_atomic(); 179 180 if (!kcm->rx_wait && !kcm->rx_psock && 181 sk_rmem_alloc_get(sk) < sk->sk_rcvlowat) { 182 spin_lock_bh(&mux->rx_lock); 183 kcm_rcv_ready(kcm); 184 spin_unlock_bh(&mux->rx_lock); 185 } 186 } 187 188 static int kcm_queue_rcv_skb(struct sock *sk, struct sk_buff *skb) 189 { 190 struct sk_buff_head *list = &sk->sk_receive_queue; 191 192 if (atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf) 193 return -ENOMEM; 194 195 if (!sk_rmem_schedule(sk, skb, skb->truesize)) 196 return -ENOBUFS; 197 198 skb->dev = NULL; 199 200 skb_orphan(skb); 201 skb->sk = sk; 202 skb->destructor = kcm_rfree; 203 atomic_add(skb->truesize, &sk->sk_rmem_alloc); 204 sk_mem_charge(sk, skb->truesize); 205 206 skb_queue_tail(list, skb); 207 208 if (!sock_flag(sk, SOCK_DEAD)) 209 sk->sk_data_ready(sk); 210 211 return 0; 212 } 213 214 /* Requeue received messages for a kcm socket to other kcm sockets. This is 215 * called with a kcm socket is receive disabled. 216 * RX mux lock held. 217 */ 218 static void requeue_rx_msgs(struct kcm_mux *mux, struct sk_buff_head *head) 219 { 220 struct sk_buff *skb; 221 struct kcm_sock *kcm; 222 223 while ((skb = __skb_dequeue(head))) { 224 /* Reset destructor to avoid calling kcm_rcv_ready */ 225 skb->destructor = sock_rfree; 226 skb_orphan(skb); 227 try_again: 228 if (list_empty(&mux->kcm_rx_waiters)) { 229 skb_queue_tail(&mux->rx_hold_queue, skb); 230 continue; 231 } 232 233 kcm = list_first_entry(&mux->kcm_rx_waiters, 234 struct kcm_sock, wait_rx_list); 235 236 if (kcm_queue_rcv_skb(&kcm->sk, skb)) { 237 /* Should mean socket buffer full */ 238 list_del(&kcm->wait_rx_list); 239 kcm->rx_wait = false; 240 241 /* Commit rx_wait to read in kcm_free */ 242 smp_wmb(); 243 244 goto try_again; 245 } 246 } 247 } 248 249 /* Lower sock lock held */ 250 static struct kcm_sock *reserve_rx_kcm(struct kcm_psock *psock, 251 struct sk_buff *head) 252 { 253 struct kcm_mux *mux = psock->mux; 254 struct kcm_sock *kcm; 255 256 WARN_ON(psock->ready_rx_msg); 257 258 if (psock->rx_kcm) 259 return psock->rx_kcm; 260 261 spin_lock_bh(&mux->rx_lock); 262 263 if (psock->rx_kcm) { 264 spin_unlock_bh(&mux->rx_lock); 265 return psock->rx_kcm; 266 } 267 268 kcm_update_rx_mux_stats(mux, psock); 269 270 if (list_empty(&mux->kcm_rx_waiters)) { 271 psock->ready_rx_msg = head; 272 strp_pause(&psock->strp); 273 list_add_tail(&psock->psock_ready_list, 274 &mux->psocks_ready); 275 spin_unlock_bh(&mux->rx_lock); 276 return NULL; 277 } 278 279 kcm = list_first_entry(&mux->kcm_rx_waiters, 280 struct kcm_sock, wait_rx_list); 281 list_del(&kcm->wait_rx_list); 282 kcm->rx_wait = false; 283 284 psock->rx_kcm = kcm; 285 kcm->rx_psock = psock; 286 287 spin_unlock_bh(&mux->rx_lock); 288 289 return kcm; 290 } 291 292 static void kcm_done(struct kcm_sock *kcm); 293 294 static void kcm_done_work(struct work_struct *w) 295 { 296 kcm_done(container_of(w, struct kcm_sock, done_work)); 297 } 298 299 /* Lower sock held */ 300 static void unreserve_rx_kcm(struct kcm_psock *psock, 301 bool rcv_ready) 302 { 303 struct kcm_sock *kcm = psock->rx_kcm; 304 struct kcm_mux *mux = psock->mux; 305 306 if (!kcm) 307 return; 308 309 spin_lock_bh(&mux->rx_lock); 310 311 psock->rx_kcm = NULL; 312 kcm->rx_psock = NULL; 313 314 /* Commit kcm->rx_psock before sk_rmem_alloc_get to sync with 315 * kcm_rfree 316 */ 317 smp_mb(); 318 319 if (unlikely(kcm->done)) { 320 spin_unlock_bh(&mux->rx_lock); 321 322 /* Need to run kcm_done in a task since we need to qcquire 323 * callback locks which may already be held here. 324 */ 325 INIT_WORK(&kcm->done_work, kcm_done_work); 326 schedule_work(&kcm->done_work); 327 return; 328 } 329 330 if (unlikely(kcm->rx_disabled)) { 331 requeue_rx_msgs(mux, &kcm->sk.sk_receive_queue); 332 } else if (rcv_ready || unlikely(!sk_rmem_alloc_get(&kcm->sk))) { 333 /* Check for degenerative race with rx_wait that all 334 * data was dequeued (accounted for in kcm_rfree). 335 */ 336 kcm_rcv_ready(kcm); 337 } 338 spin_unlock_bh(&mux->rx_lock); 339 } 340 341 /* Lower sock lock held */ 342 static void psock_data_ready(struct sock *sk) 343 { 344 struct kcm_psock *psock; 345 346 read_lock_bh(&sk->sk_callback_lock); 347 348 psock = (struct kcm_psock *)sk->sk_user_data; 349 if (likely(psock)) 350 strp_data_ready(&psock->strp); 351 352 read_unlock_bh(&sk->sk_callback_lock); 353 } 354 355 /* Called with lower sock held */ 356 static void kcm_rcv_strparser(struct strparser *strp, struct sk_buff *skb) 357 { 358 struct kcm_psock *psock = container_of(strp, struct kcm_psock, strp); 359 struct kcm_sock *kcm; 360 361 try_queue: 362 kcm = reserve_rx_kcm(psock, skb); 363 if (!kcm) { 364 /* Unable to reserve a KCM, message is held in psock and strp 365 * is paused. 366 */ 367 return; 368 } 369 370 if (kcm_queue_rcv_skb(&kcm->sk, skb)) { 371 /* Should mean socket buffer full */ 372 unreserve_rx_kcm(psock, false); 373 goto try_queue; 374 } 375 } 376 377 static int kcm_parse_func_strparser(struct strparser *strp, struct sk_buff *skb) 378 { 379 struct kcm_psock *psock = container_of(strp, struct kcm_psock, strp); 380 struct bpf_prog *prog = psock->bpf_prog; 381 382 return (*prog->bpf_func)(skb, prog->insnsi); 383 } 384 385 static int kcm_read_sock_done(struct strparser *strp, int err) 386 { 387 struct kcm_psock *psock = container_of(strp, struct kcm_psock, strp); 388 389 unreserve_rx_kcm(psock, true); 390 391 return err; 392 } 393 394 static void psock_state_change(struct sock *sk) 395 { 396 /* TCP only does a POLLIN for a half close. Do a POLLHUP here 397 * since application will normally not poll with POLLIN 398 * on the TCP sockets. 399 */ 400 401 report_csk_error(sk, EPIPE); 402 } 403 404 static void psock_write_space(struct sock *sk) 405 { 406 struct kcm_psock *psock; 407 struct kcm_mux *mux; 408 struct kcm_sock *kcm; 409 410 read_lock_bh(&sk->sk_callback_lock); 411 412 psock = (struct kcm_psock *)sk->sk_user_data; 413 if (unlikely(!psock)) 414 goto out; 415 mux = psock->mux; 416 417 spin_lock_bh(&mux->lock); 418 419 /* Check if the socket is reserved so someone is waiting for sending. */ 420 kcm = psock->tx_kcm; 421 if (kcm && !unlikely(kcm->tx_stopped)) 422 queue_work(kcm_wq, &kcm->tx_work); 423 424 spin_unlock_bh(&mux->lock); 425 out: 426 read_unlock_bh(&sk->sk_callback_lock); 427 } 428 429 static void unreserve_psock(struct kcm_sock *kcm); 430 431 /* kcm sock is locked. */ 432 static struct kcm_psock *reserve_psock(struct kcm_sock *kcm) 433 { 434 struct kcm_mux *mux = kcm->mux; 435 struct kcm_psock *psock; 436 437 psock = kcm->tx_psock; 438 439 smp_rmb(); /* Must read tx_psock before tx_wait */ 440 441 if (psock) { 442 WARN_ON(kcm->tx_wait); 443 if (unlikely(psock->tx_stopped)) 444 unreserve_psock(kcm); 445 else 446 return kcm->tx_psock; 447 } 448 449 spin_lock_bh(&mux->lock); 450 451 /* Check again under lock to see if psock was reserved for this 452 * psock via psock_unreserve. 453 */ 454 psock = kcm->tx_psock; 455 if (unlikely(psock)) { 456 WARN_ON(kcm->tx_wait); 457 spin_unlock_bh(&mux->lock); 458 return kcm->tx_psock; 459 } 460 461 if (!list_empty(&mux->psocks_avail)) { 462 psock = list_first_entry(&mux->psocks_avail, 463 struct kcm_psock, 464 psock_avail_list); 465 list_del(&psock->psock_avail_list); 466 if (kcm->tx_wait) { 467 list_del(&kcm->wait_psock_list); 468 kcm->tx_wait = false; 469 } 470 kcm->tx_psock = psock; 471 psock->tx_kcm = kcm; 472 KCM_STATS_INCR(psock->stats.reserved); 473 } else if (!kcm->tx_wait) { 474 list_add_tail(&kcm->wait_psock_list, 475 &mux->kcm_tx_waiters); 476 kcm->tx_wait = true; 477 } 478 479 spin_unlock_bh(&mux->lock); 480 481 return psock; 482 } 483 484 /* mux lock held */ 485 static void psock_now_avail(struct kcm_psock *psock) 486 { 487 struct kcm_mux *mux = psock->mux; 488 struct kcm_sock *kcm; 489 490 if (list_empty(&mux->kcm_tx_waiters)) { 491 list_add_tail(&psock->psock_avail_list, 492 &mux->psocks_avail); 493 } else { 494 kcm = list_first_entry(&mux->kcm_tx_waiters, 495 struct kcm_sock, 496 wait_psock_list); 497 list_del(&kcm->wait_psock_list); 498 kcm->tx_wait = false; 499 psock->tx_kcm = kcm; 500 501 /* Commit before changing tx_psock since that is read in 502 * reserve_psock before queuing work. 503 */ 504 smp_mb(); 505 506 kcm->tx_psock = psock; 507 KCM_STATS_INCR(psock->stats.reserved); 508 queue_work(kcm_wq, &kcm->tx_work); 509 } 510 } 511 512 /* kcm sock is locked. */ 513 static void unreserve_psock(struct kcm_sock *kcm) 514 { 515 struct kcm_psock *psock; 516 struct kcm_mux *mux = kcm->mux; 517 518 spin_lock_bh(&mux->lock); 519 520 psock = kcm->tx_psock; 521 522 if (WARN_ON(!psock)) { 523 spin_unlock_bh(&mux->lock); 524 return; 525 } 526 527 smp_rmb(); /* Read tx_psock before tx_wait */ 528 529 kcm_update_tx_mux_stats(mux, psock); 530 531 WARN_ON(kcm->tx_wait); 532 533 kcm->tx_psock = NULL; 534 psock->tx_kcm = NULL; 535 KCM_STATS_INCR(psock->stats.unreserved); 536 537 if (unlikely(psock->tx_stopped)) { 538 if (psock->done) { 539 /* Deferred free */ 540 list_del(&psock->psock_list); 541 mux->psocks_cnt--; 542 sock_put(psock->sk); 543 fput(psock->sk->sk_socket->file); 544 kmem_cache_free(kcm_psockp, psock); 545 } 546 547 /* Don't put back on available list */ 548 549 spin_unlock_bh(&mux->lock); 550 551 return; 552 } 553 554 psock_now_avail(psock); 555 556 spin_unlock_bh(&mux->lock); 557 } 558 559 static void kcm_report_tx_retry(struct kcm_sock *kcm) 560 { 561 struct kcm_mux *mux = kcm->mux; 562 563 spin_lock_bh(&mux->lock); 564 KCM_STATS_INCR(mux->stats.tx_retries); 565 spin_unlock_bh(&mux->lock); 566 } 567 568 /* Write any messages ready on the kcm socket. Called with kcm sock lock 569 * held. Return bytes actually sent or error. 570 */ 571 static int kcm_write_msgs(struct kcm_sock *kcm) 572 { 573 struct sock *sk = &kcm->sk; 574 struct kcm_psock *psock; 575 struct sk_buff *skb, *head; 576 struct kcm_tx_msg *txm; 577 unsigned short fragidx, frag_offset; 578 unsigned int sent, total_sent = 0; 579 int ret = 0; 580 581 kcm->tx_wait_more = false; 582 psock = kcm->tx_psock; 583 if (unlikely(psock && psock->tx_stopped)) { 584 /* A reserved psock was aborted asynchronously. Unreserve 585 * it and we'll retry the message. 586 */ 587 unreserve_psock(kcm); 588 kcm_report_tx_retry(kcm); 589 if (skb_queue_empty(&sk->sk_write_queue)) 590 return 0; 591 592 kcm_tx_msg(skb_peek(&sk->sk_write_queue))->sent = 0; 593 594 } else if (skb_queue_empty(&sk->sk_write_queue)) { 595 return 0; 596 } 597 598 head = skb_peek(&sk->sk_write_queue); 599 txm = kcm_tx_msg(head); 600 601 if (txm->sent) { 602 /* Send of first skbuff in queue already in progress */ 603 if (WARN_ON(!psock)) { 604 ret = -EINVAL; 605 goto out; 606 } 607 sent = txm->sent; 608 frag_offset = txm->frag_offset; 609 fragidx = txm->fragidx; 610 skb = txm->frag_skb; 611 612 goto do_frag; 613 } 614 615 try_again: 616 psock = reserve_psock(kcm); 617 if (!psock) 618 goto out; 619 620 do { 621 skb = head; 622 txm = kcm_tx_msg(head); 623 sent = 0; 624 625 do_frag_list: 626 if (WARN_ON(!skb_shinfo(skb)->nr_frags)) { 627 ret = -EINVAL; 628 goto out; 629 } 630 631 for (fragidx = 0; fragidx < skb_shinfo(skb)->nr_frags; 632 fragidx++) { 633 skb_frag_t *frag; 634 635 frag_offset = 0; 636 do_frag: 637 frag = &skb_shinfo(skb)->frags[fragidx]; 638 if (WARN_ON(!frag->size)) { 639 ret = -EINVAL; 640 goto out; 641 } 642 643 ret = kernel_sendpage(psock->sk->sk_socket, 644 frag->page.p, 645 frag->page_offset + frag_offset, 646 frag->size - frag_offset, 647 MSG_DONTWAIT); 648 if (ret <= 0) { 649 if (ret == -EAGAIN) { 650 /* Save state to try again when there's 651 * write space on the socket 652 */ 653 txm->sent = sent; 654 txm->frag_offset = frag_offset; 655 txm->fragidx = fragidx; 656 txm->frag_skb = skb; 657 658 ret = 0; 659 goto out; 660 } 661 662 /* Hard failure in sending message, abort this 663 * psock since it has lost framing 664 * synchonization and retry sending the 665 * message from the beginning. 666 */ 667 kcm_abort_tx_psock(psock, ret ? -ret : EPIPE, 668 true); 669 unreserve_psock(kcm); 670 671 txm->sent = 0; 672 kcm_report_tx_retry(kcm); 673 ret = 0; 674 675 goto try_again; 676 } 677 678 sent += ret; 679 frag_offset += ret; 680 KCM_STATS_ADD(psock->stats.tx_bytes, ret); 681 if (frag_offset < frag->size) { 682 /* Not finished with this frag */ 683 goto do_frag; 684 } 685 } 686 687 if (skb == head) { 688 if (skb_has_frag_list(skb)) { 689 skb = skb_shinfo(skb)->frag_list; 690 goto do_frag_list; 691 } 692 } else if (skb->next) { 693 skb = skb->next; 694 goto do_frag_list; 695 } 696 697 /* Successfully sent the whole packet, account for it. */ 698 skb_dequeue(&sk->sk_write_queue); 699 kfree_skb(head); 700 sk->sk_wmem_queued -= sent; 701 total_sent += sent; 702 KCM_STATS_INCR(psock->stats.tx_msgs); 703 } while ((head = skb_peek(&sk->sk_write_queue))); 704 out: 705 if (!head) { 706 /* Done with all queued messages. */ 707 WARN_ON(!skb_queue_empty(&sk->sk_write_queue)); 708 unreserve_psock(kcm); 709 } 710 711 /* Check if write space is available */ 712 sk->sk_write_space(sk); 713 714 return total_sent ? : ret; 715 } 716 717 static void kcm_tx_work(struct work_struct *w) 718 { 719 struct kcm_sock *kcm = container_of(w, struct kcm_sock, tx_work); 720 struct sock *sk = &kcm->sk; 721 int err; 722 723 lock_sock(sk); 724 725 /* Primarily for SOCK_DGRAM sockets, also handle asynchronous tx 726 * aborts 727 */ 728 err = kcm_write_msgs(kcm); 729 if (err < 0) { 730 /* Hard failure in write, report error on KCM socket */ 731 pr_warn("KCM: Hard failure on kcm_write_msgs %d\n", err); 732 report_csk_error(&kcm->sk, -err); 733 goto out; 734 } 735 736 /* Primarily for SOCK_SEQPACKET sockets */ 737 if (likely(sk->sk_socket) && 738 test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) { 739 clear_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 740 sk->sk_write_space(sk); 741 } 742 743 out: 744 release_sock(sk); 745 } 746 747 static void kcm_push(struct kcm_sock *kcm) 748 { 749 if (kcm->tx_wait_more) 750 kcm_write_msgs(kcm); 751 } 752 753 static ssize_t kcm_sendpage(struct socket *sock, struct page *page, 754 int offset, size_t size, int flags) 755 756 { 757 struct sock *sk = sock->sk; 758 struct kcm_sock *kcm = kcm_sk(sk); 759 struct sk_buff *skb = NULL, *head = NULL; 760 long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT); 761 bool eor; 762 int err = 0; 763 int i; 764 765 if (flags & MSG_SENDPAGE_NOTLAST) 766 flags |= MSG_MORE; 767 768 /* No MSG_EOR from splice, only look at MSG_MORE */ 769 eor = !(flags & MSG_MORE); 770 771 lock_sock(sk); 772 773 sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk); 774 775 err = -EPIPE; 776 if (sk->sk_err) 777 goto out_error; 778 779 if (kcm->seq_skb) { 780 /* Previously opened message */ 781 head = kcm->seq_skb; 782 skb = kcm_tx_msg(head)->last_skb; 783 i = skb_shinfo(skb)->nr_frags; 784 785 if (skb_can_coalesce(skb, i, page, offset)) { 786 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], size); 787 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG; 788 goto coalesced; 789 } 790 791 if (i >= MAX_SKB_FRAGS) { 792 struct sk_buff *tskb; 793 794 tskb = alloc_skb(0, sk->sk_allocation); 795 while (!tskb) { 796 kcm_push(kcm); 797 err = sk_stream_wait_memory(sk, &timeo); 798 if (err) 799 goto out_error; 800 } 801 802 if (head == skb) 803 skb_shinfo(head)->frag_list = tskb; 804 else 805 skb->next = tskb; 806 807 skb = tskb; 808 skb->ip_summed = CHECKSUM_UNNECESSARY; 809 i = 0; 810 } 811 } else { 812 /* Call the sk_stream functions to manage the sndbuf mem. */ 813 if (!sk_stream_memory_free(sk)) { 814 kcm_push(kcm); 815 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 816 err = sk_stream_wait_memory(sk, &timeo); 817 if (err) 818 goto out_error; 819 } 820 821 head = alloc_skb(0, sk->sk_allocation); 822 while (!head) { 823 kcm_push(kcm); 824 err = sk_stream_wait_memory(sk, &timeo); 825 if (err) 826 goto out_error; 827 } 828 829 skb = head; 830 i = 0; 831 } 832 833 get_page(page); 834 skb_fill_page_desc(skb, i, page, offset, size); 835 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG; 836 837 coalesced: 838 skb->len += size; 839 skb->data_len += size; 840 skb->truesize += size; 841 sk->sk_wmem_queued += size; 842 sk_mem_charge(sk, size); 843 844 if (head != skb) { 845 head->len += size; 846 head->data_len += size; 847 head->truesize += size; 848 } 849 850 if (eor) { 851 bool not_busy = skb_queue_empty(&sk->sk_write_queue); 852 853 /* Message complete, queue it on send buffer */ 854 __skb_queue_tail(&sk->sk_write_queue, head); 855 kcm->seq_skb = NULL; 856 KCM_STATS_INCR(kcm->stats.tx_msgs); 857 858 if (flags & MSG_BATCH) { 859 kcm->tx_wait_more = true; 860 } else if (kcm->tx_wait_more || not_busy) { 861 err = kcm_write_msgs(kcm); 862 if (err < 0) { 863 /* We got a hard error in write_msgs but have 864 * already queued this message. Report an error 865 * in the socket, but don't affect return value 866 * from sendmsg 867 */ 868 pr_warn("KCM: Hard failure on kcm_write_msgs\n"); 869 report_csk_error(&kcm->sk, -err); 870 } 871 } 872 } else { 873 /* Message not complete, save state */ 874 kcm->seq_skb = head; 875 kcm_tx_msg(head)->last_skb = skb; 876 } 877 878 KCM_STATS_ADD(kcm->stats.tx_bytes, size); 879 880 release_sock(sk); 881 return size; 882 883 out_error: 884 kcm_push(kcm); 885 886 err = sk_stream_error(sk, flags, err); 887 888 /* make sure we wake any epoll edge trigger waiter */ 889 if (unlikely(skb_queue_len(&sk->sk_write_queue) == 0 && err == -EAGAIN)) 890 sk->sk_write_space(sk); 891 892 release_sock(sk); 893 return err; 894 } 895 896 static int kcm_sendmsg(struct socket *sock, struct msghdr *msg, size_t len) 897 { 898 struct sock *sk = sock->sk; 899 struct kcm_sock *kcm = kcm_sk(sk); 900 struct sk_buff *skb = NULL, *head = NULL; 901 size_t copy, copied = 0; 902 long timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT); 903 int eor = (sock->type == SOCK_DGRAM) ? 904 !(msg->msg_flags & MSG_MORE) : !!(msg->msg_flags & MSG_EOR); 905 int err = -EPIPE; 906 907 lock_sock(sk); 908 909 /* Per tcp_sendmsg this should be in poll */ 910 sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk); 911 912 if (sk->sk_err) 913 goto out_error; 914 915 if (kcm->seq_skb) { 916 /* Previously opened message */ 917 head = kcm->seq_skb; 918 skb = kcm_tx_msg(head)->last_skb; 919 goto start; 920 } 921 922 /* Call the sk_stream functions to manage the sndbuf mem. */ 923 if (!sk_stream_memory_free(sk)) { 924 kcm_push(kcm); 925 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 926 err = sk_stream_wait_memory(sk, &timeo); 927 if (err) 928 goto out_error; 929 } 930 931 /* New message, alloc head skb */ 932 head = alloc_skb(0, sk->sk_allocation); 933 while (!head) { 934 kcm_push(kcm); 935 err = sk_stream_wait_memory(sk, &timeo); 936 if (err) 937 goto out_error; 938 939 head = alloc_skb(0, sk->sk_allocation); 940 } 941 942 skb = head; 943 944 /* Set ip_summed to CHECKSUM_UNNECESSARY to avoid calling 945 * csum_and_copy_from_iter from skb_do_copy_data_nocache. 946 */ 947 skb->ip_summed = CHECKSUM_UNNECESSARY; 948 949 start: 950 while (msg_data_left(msg)) { 951 bool merge = true; 952 int i = skb_shinfo(skb)->nr_frags; 953 struct page_frag *pfrag = sk_page_frag(sk); 954 955 if (!sk_page_frag_refill(sk, pfrag)) 956 goto wait_for_memory; 957 958 if (!skb_can_coalesce(skb, i, pfrag->page, 959 pfrag->offset)) { 960 if (i == MAX_SKB_FRAGS) { 961 struct sk_buff *tskb; 962 963 tskb = alloc_skb(0, sk->sk_allocation); 964 if (!tskb) 965 goto wait_for_memory; 966 967 if (head == skb) 968 skb_shinfo(head)->frag_list = tskb; 969 else 970 skb->next = tskb; 971 972 skb = tskb; 973 skb->ip_summed = CHECKSUM_UNNECESSARY; 974 continue; 975 } 976 merge = false; 977 } 978 979 copy = min_t(int, msg_data_left(msg), 980 pfrag->size - pfrag->offset); 981 982 if (!sk_wmem_schedule(sk, copy)) 983 goto wait_for_memory; 984 985 err = skb_copy_to_page_nocache(sk, &msg->msg_iter, skb, 986 pfrag->page, 987 pfrag->offset, 988 copy); 989 if (err) 990 goto out_error; 991 992 /* Update the skb. */ 993 if (merge) { 994 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy); 995 } else { 996 skb_fill_page_desc(skb, i, pfrag->page, 997 pfrag->offset, copy); 998 get_page(pfrag->page); 999 } 1000 1001 pfrag->offset += copy; 1002 copied += copy; 1003 if (head != skb) { 1004 head->len += copy; 1005 head->data_len += copy; 1006 } 1007 1008 continue; 1009 1010 wait_for_memory: 1011 kcm_push(kcm); 1012 err = sk_stream_wait_memory(sk, &timeo); 1013 if (err) 1014 goto out_error; 1015 } 1016 1017 if (eor) { 1018 bool not_busy = skb_queue_empty(&sk->sk_write_queue); 1019 1020 /* Message complete, queue it on send buffer */ 1021 __skb_queue_tail(&sk->sk_write_queue, head); 1022 kcm->seq_skb = NULL; 1023 KCM_STATS_INCR(kcm->stats.tx_msgs); 1024 1025 if (msg->msg_flags & MSG_BATCH) { 1026 kcm->tx_wait_more = true; 1027 } else if (kcm->tx_wait_more || not_busy) { 1028 err = kcm_write_msgs(kcm); 1029 if (err < 0) { 1030 /* We got a hard error in write_msgs but have 1031 * already queued this message. Report an error 1032 * in the socket, but don't affect return value 1033 * from sendmsg 1034 */ 1035 pr_warn("KCM: Hard failure on kcm_write_msgs\n"); 1036 report_csk_error(&kcm->sk, -err); 1037 } 1038 } 1039 } else { 1040 /* Message not complete, save state */ 1041 partial_message: 1042 kcm->seq_skb = head; 1043 kcm_tx_msg(head)->last_skb = skb; 1044 } 1045 1046 KCM_STATS_ADD(kcm->stats.tx_bytes, copied); 1047 1048 release_sock(sk); 1049 return copied; 1050 1051 out_error: 1052 kcm_push(kcm); 1053 1054 if (copied && sock->type == SOCK_SEQPACKET) { 1055 /* Wrote some bytes before encountering an 1056 * error, return partial success. 1057 */ 1058 goto partial_message; 1059 } 1060 1061 if (head != kcm->seq_skb) 1062 kfree_skb(head); 1063 1064 err = sk_stream_error(sk, msg->msg_flags, err); 1065 1066 /* make sure we wake any epoll edge trigger waiter */ 1067 if (unlikely(skb_queue_len(&sk->sk_write_queue) == 0 && err == -EAGAIN)) 1068 sk->sk_write_space(sk); 1069 1070 release_sock(sk); 1071 return err; 1072 } 1073 1074 static struct sk_buff *kcm_wait_data(struct sock *sk, int flags, 1075 long timeo, int *err) 1076 { 1077 struct sk_buff *skb; 1078 1079 while (!(skb = skb_peek(&sk->sk_receive_queue))) { 1080 if (sk->sk_err) { 1081 *err = sock_error(sk); 1082 return NULL; 1083 } 1084 1085 if (sock_flag(sk, SOCK_DONE)) 1086 return NULL; 1087 1088 if ((flags & MSG_DONTWAIT) || !timeo) { 1089 *err = -EAGAIN; 1090 return NULL; 1091 } 1092 1093 sk_wait_data(sk, &timeo, NULL); 1094 1095 /* Handle signals */ 1096 if (signal_pending(current)) { 1097 *err = sock_intr_errno(timeo); 1098 return NULL; 1099 } 1100 } 1101 1102 return skb; 1103 } 1104 1105 static int kcm_recvmsg(struct socket *sock, struct msghdr *msg, 1106 size_t len, int flags) 1107 { 1108 struct sock *sk = sock->sk; 1109 struct kcm_sock *kcm = kcm_sk(sk); 1110 int err = 0; 1111 long timeo; 1112 struct strp_rx_msg *rxm; 1113 int copied = 0; 1114 struct sk_buff *skb; 1115 1116 timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT); 1117 1118 lock_sock(sk); 1119 1120 skb = kcm_wait_data(sk, flags, timeo, &err); 1121 if (!skb) 1122 goto out; 1123 1124 /* Okay, have a message on the receive queue */ 1125 1126 rxm = strp_rx_msg(skb); 1127 1128 if (len > rxm->full_len) 1129 len = rxm->full_len; 1130 1131 err = skb_copy_datagram_msg(skb, rxm->offset, msg, len); 1132 if (err < 0) 1133 goto out; 1134 1135 copied = len; 1136 if (likely(!(flags & MSG_PEEK))) { 1137 KCM_STATS_ADD(kcm->stats.rx_bytes, copied); 1138 if (copied < rxm->full_len) { 1139 if (sock->type == SOCK_DGRAM) { 1140 /* Truncated message */ 1141 msg->msg_flags |= MSG_TRUNC; 1142 goto msg_finished; 1143 } 1144 rxm->offset += copied; 1145 rxm->full_len -= copied; 1146 } else { 1147 msg_finished: 1148 /* Finished with message */ 1149 msg->msg_flags |= MSG_EOR; 1150 KCM_STATS_INCR(kcm->stats.rx_msgs); 1151 skb_unlink(skb, &sk->sk_receive_queue); 1152 kfree_skb(skb); 1153 } 1154 } 1155 1156 out: 1157 release_sock(sk); 1158 1159 return copied ? : err; 1160 } 1161 1162 static ssize_t kcm_sock_splice(struct sock *sk, 1163 struct pipe_inode_info *pipe, 1164 struct splice_pipe_desc *spd) 1165 { 1166 int ret; 1167 1168 release_sock(sk); 1169 ret = splice_to_pipe(pipe, spd); 1170 lock_sock(sk); 1171 1172 return ret; 1173 } 1174 1175 static ssize_t kcm_splice_read(struct socket *sock, loff_t *ppos, 1176 struct pipe_inode_info *pipe, size_t len, 1177 unsigned int flags) 1178 { 1179 struct sock *sk = sock->sk; 1180 struct kcm_sock *kcm = kcm_sk(sk); 1181 long timeo; 1182 struct strp_rx_msg *rxm; 1183 int err = 0; 1184 ssize_t copied; 1185 struct sk_buff *skb; 1186 1187 /* Only support splice for SOCKSEQPACKET */ 1188 1189 timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT); 1190 1191 lock_sock(sk); 1192 1193 skb = kcm_wait_data(sk, flags, timeo, &err); 1194 if (!skb) 1195 goto err_out; 1196 1197 /* Okay, have a message on the receive queue */ 1198 1199 rxm = strp_rx_msg(skb); 1200 1201 if (len > rxm->full_len) 1202 len = rxm->full_len; 1203 1204 copied = skb_splice_bits(skb, sk, rxm->offset, pipe, len, flags, 1205 kcm_sock_splice); 1206 if (copied < 0) { 1207 err = copied; 1208 goto err_out; 1209 } 1210 1211 KCM_STATS_ADD(kcm->stats.rx_bytes, copied); 1212 1213 rxm->offset += copied; 1214 rxm->full_len -= copied; 1215 1216 /* We have no way to return MSG_EOR. If all the bytes have been 1217 * read we still leave the message in the receive socket buffer. 1218 * A subsequent recvmsg needs to be done to return MSG_EOR and 1219 * finish reading the message. 1220 */ 1221 1222 release_sock(sk); 1223 1224 return copied; 1225 1226 err_out: 1227 release_sock(sk); 1228 1229 return err; 1230 } 1231 1232 /* kcm sock lock held */ 1233 static void kcm_recv_disable(struct kcm_sock *kcm) 1234 { 1235 struct kcm_mux *mux = kcm->mux; 1236 1237 if (kcm->rx_disabled) 1238 return; 1239 1240 spin_lock_bh(&mux->rx_lock); 1241 1242 kcm->rx_disabled = 1; 1243 1244 /* If a psock is reserved we'll do cleanup in unreserve */ 1245 if (!kcm->rx_psock) { 1246 if (kcm->rx_wait) { 1247 list_del(&kcm->wait_rx_list); 1248 kcm->rx_wait = false; 1249 } 1250 1251 requeue_rx_msgs(mux, &kcm->sk.sk_receive_queue); 1252 } 1253 1254 spin_unlock_bh(&mux->rx_lock); 1255 } 1256 1257 /* kcm sock lock held */ 1258 static void kcm_recv_enable(struct kcm_sock *kcm) 1259 { 1260 struct kcm_mux *mux = kcm->mux; 1261 1262 if (!kcm->rx_disabled) 1263 return; 1264 1265 spin_lock_bh(&mux->rx_lock); 1266 1267 kcm->rx_disabled = 0; 1268 kcm_rcv_ready(kcm); 1269 1270 spin_unlock_bh(&mux->rx_lock); 1271 } 1272 1273 static int kcm_setsockopt(struct socket *sock, int level, int optname, 1274 char __user *optval, unsigned int optlen) 1275 { 1276 struct kcm_sock *kcm = kcm_sk(sock->sk); 1277 int val, valbool; 1278 int err = 0; 1279 1280 if (level != SOL_KCM) 1281 return -ENOPROTOOPT; 1282 1283 if (optlen < sizeof(int)) 1284 return -EINVAL; 1285 1286 if (get_user(val, (int __user *)optval)) 1287 return -EINVAL; 1288 1289 valbool = val ? 1 : 0; 1290 1291 switch (optname) { 1292 case KCM_RECV_DISABLE: 1293 lock_sock(&kcm->sk); 1294 if (valbool) 1295 kcm_recv_disable(kcm); 1296 else 1297 kcm_recv_enable(kcm); 1298 release_sock(&kcm->sk); 1299 break; 1300 default: 1301 err = -ENOPROTOOPT; 1302 } 1303 1304 return err; 1305 } 1306 1307 static int kcm_getsockopt(struct socket *sock, int level, int optname, 1308 char __user *optval, int __user *optlen) 1309 { 1310 struct kcm_sock *kcm = kcm_sk(sock->sk); 1311 int val, len; 1312 1313 if (level != SOL_KCM) 1314 return -ENOPROTOOPT; 1315 1316 if (get_user(len, optlen)) 1317 return -EFAULT; 1318 1319 len = min_t(unsigned int, len, sizeof(int)); 1320 if (len < 0) 1321 return -EINVAL; 1322 1323 switch (optname) { 1324 case KCM_RECV_DISABLE: 1325 val = kcm->rx_disabled; 1326 break; 1327 default: 1328 return -ENOPROTOOPT; 1329 } 1330 1331 if (put_user(len, optlen)) 1332 return -EFAULT; 1333 if (copy_to_user(optval, &val, len)) 1334 return -EFAULT; 1335 return 0; 1336 } 1337 1338 static void init_kcm_sock(struct kcm_sock *kcm, struct kcm_mux *mux) 1339 { 1340 struct kcm_sock *tkcm; 1341 struct list_head *head; 1342 int index = 0; 1343 1344 /* For SOCK_SEQPACKET sock type, datagram_poll checks the sk_state, so 1345 * we set sk_state, otherwise epoll_wait always returns right away with 1346 * POLLHUP 1347 */ 1348 kcm->sk.sk_state = TCP_ESTABLISHED; 1349 1350 /* Add to mux's kcm sockets list */ 1351 kcm->mux = mux; 1352 spin_lock_bh(&mux->lock); 1353 1354 head = &mux->kcm_socks; 1355 list_for_each_entry(tkcm, &mux->kcm_socks, kcm_sock_list) { 1356 if (tkcm->index != index) 1357 break; 1358 head = &tkcm->kcm_sock_list; 1359 index++; 1360 } 1361 1362 list_add(&kcm->kcm_sock_list, head); 1363 kcm->index = index; 1364 1365 mux->kcm_socks_cnt++; 1366 spin_unlock_bh(&mux->lock); 1367 1368 INIT_WORK(&kcm->tx_work, kcm_tx_work); 1369 1370 spin_lock_bh(&mux->rx_lock); 1371 kcm_rcv_ready(kcm); 1372 spin_unlock_bh(&mux->rx_lock); 1373 } 1374 1375 static int kcm_attach(struct socket *sock, struct socket *csock, 1376 struct bpf_prog *prog) 1377 { 1378 struct kcm_sock *kcm = kcm_sk(sock->sk); 1379 struct kcm_mux *mux = kcm->mux; 1380 struct sock *csk; 1381 struct kcm_psock *psock = NULL, *tpsock; 1382 struct list_head *head; 1383 int index = 0; 1384 struct strp_callbacks cb; 1385 int err; 1386 1387 csk = csock->sk; 1388 if (!csk) 1389 return -EINVAL; 1390 1391 psock = kmem_cache_zalloc(kcm_psockp, GFP_KERNEL); 1392 if (!psock) 1393 return -ENOMEM; 1394 1395 psock->mux = mux; 1396 psock->sk = csk; 1397 psock->bpf_prog = prog; 1398 1399 cb.rcv_msg = kcm_rcv_strparser; 1400 cb.abort_parser = NULL; 1401 cb.parse_msg = kcm_parse_func_strparser; 1402 cb.read_sock_done = kcm_read_sock_done; 1403 1404 err = strp_init(&psock->strp, csk, &cb); 1405 if (err) { 1406 kmem_cache_free(kcm_psockp, psock); 1407 return err; 1408 } 1409 1410 sock_hold(csk); 1411 1412 write_lock_bh(&csk->sk_callback_lock); 1413 psock->save_data_ready = csk->sk_data_ready; 1414 psock->save_write_space = csk->sk_write_space; 1415 psock->save_state_change = csk->sk_state_change; 1416 csk->sk_user_data = psock; 1417 csk->sk_data_ready = psock_data_ready; 1418 csk->sk_write_space = psock_write_space; 1419 csk->sk_state_change = psock_state_change; 1420 write_unlock_bh(&csk->sk_callback_lock); 1421 1422 /* Finished initialization, now add the psock to the MUX. */ 1423 spin_lock_bh(&mux->lock); 1424 head = &mux->psocks; 1425 list_for_each_entry(tpsock, &mux->psocks, psock_list) { 1426 if (tpsock->index != index) 1427 break; 1428 head = &tpsock->psock_list; 1429 index++; 1430 } 1431 1432 list_add(&psock->psock_list, head); 1433 psock->index = index; 1434 1435 KCM_STATS_INCR(mux->stats.psock_attach); 1436 mux->psocks_cnt++; 1437 psock_now_avail(psock); 1438 spin_unlock_bh(&mux->lock); 1439 1440 /* Schedule RX work in case there are already bytes queued */ 1441 strp_check_rcv(&psock->strp); 1442 1443 return 0; 1444 } 1445 1446 static int kcm_attach_ioctl(struct socket *sock, struct kcm_attach *info) 1447 { 1448 struct socket *csock; 1449 struct bpf_prog *prog; 1450 int err; 1451 1452 csock = sockfd_lookup(info->fd, &err); 1453 if (!csock) 1454 return -ENOENT; 1455 1456 prog = bpf_prog_get_type(info->bpf_fd, BPF_PROG_TYPE_SOCKET_FILTER); 1457 if (IS_ERR(prog)) { 1458 err = PTR_ERR(prog); 1459 goto out; 1460 } 1461 1462 err = kcm_attach(sock, csock, prog); 1463 if (err) { 1464 bpf_prog_put(prog); 1465 goto out; 1466 } 1467 1468 /* Keep reference on file also */ 1469 1470 return 0; 1471 out: 1472 fput(csock->file); 1473 return err; 1474 } 1475 1476 static void kcm_unattach(struct kcm_psock *psock) 1477 { 1478 struct sock *csk = psock->sk; 1479 struct kcm_mux *mux = psock->mux; 1480 1481 lock_sock(csk); 1482 1483 /* Stop getting callbacks from TCP socket. After this there should 1484 * be no way to reserve a kcm for this psock. 1485 */ 1486 write_lock_bh(&csk->sk_callback_lock); 1487 csk->sk_user_data = NULL; 1488 csk->sk_data_ready = psock->save_data_ready; 1489 csk->sk_write_space = psock->save_write_space; 1490 csk->sk_state_change = psock->save_state_change; 1491 strp_stop(&psock->strp); 1492 1493 if (WARN_ON(psock->rx_kcm)) { 1494 write_unlock_bh(&csk->sk_callback_lock); 1495 return; 1496 } 1497 1498 spin_lock_bh(&mux->rx_lock); 1499 1500 /* Stop receiver activities. After this point psock should not be 1501 * able to get onto ready list either through callbacks or work. 1502 */ 1503 if (psock->ready_rx_msg) { 1504 list_del(&psock->psock_ready_list); 1505 kfree_skb(psock->ready_rx_msg); 1506 psock->ready_rx_msg = NULL; 1507 KCM_STATS_INCR(mux->stats.rx_ready_drops); 1508 } 1509 1510 spin_unlock_bh(&mux->rx_lock); 1511 1512 write_unlock_bh(&csk->sk_callback_lock); 1513 1514 /* Call strp_done without sock lock */ 1515 release_sock(csk); 1516 strp_done(&psock->strp); 1517 lock_sock(csk); 1518 1519 bpf_prog_put(psock->bpf_prog); 1520 1521 spin_lock_bh(&mux->lock); 1522 1523 aggregate_psock_stats(&psock->stats, &mux->aggregate_psock_stats); 1524 save_strp_stats(&psock->strp, &mux->aggregate_strp_stats); 1525 1526 KCM_STATS_INCR(mux->stats.psock_unattach); 1527 1528 if (psock->tx_kcm) { 1529 /* psock was reserved. Just mark it finished and we will clean 1530 * up in the kcm paths, we need kcm lock which can not be 1531 * acquired here. 1532 */ 1533 KCM_STATS_INCR(mux->stats.psock_unattach_rsvd); 1534 spin_unlock_bh(&mux->lock); 1535 1536 /* We are unattaching a socket that is reserved. Abort the 1537 * socket since we may be out of sync in sending on it. We need 1538 * to do this without the mux lock. 1539 */ 1540 kcm_abort_tx_psock(psock, EPIPE, false); 1541 1542 spin_lock_bh(&mux->lock); 1543 if (!psock->tx_kcm) { 1544 /* psock now unreserved in window mux was unlocked */ 1545 goto no_reserved; 1546 } 1547 psock->done = 1; 1548 1549 /* Commit done before queuing work to process it */ 1550 smp_mb(); 1551 1552 /* Queue tx work to make sure psock->done is handled */ 1553 queue_work(kcm_wq, &psock->tx_kcm->tx_work); 1554 spin_unlock_bh(&mux->lock); 1555 } else { 1556 no_reserved: 1557 if (!psock->tx_stopped) 1558 list_del(&psock->psock_avail_list); 1559 list_del(&psock->psock_list); 1560 mux->psocks_cnt--; 1561 spin_unlock_bh(&mux->lock); 1562 1563 sock_put(csk); 1564 fput(csk->sk_socket->file); 1565 kmem_cache_free(kcm_psockp, psock); 1566 } 1567 1568 release_sock(csk); 1569 } 1570 1571 static int kcm_unattach_ioctl(struct socket *sock, struct kcm_unattach *info) 1572 { 1573 struct kcm_sock *kcm = kcm_sk(sock->sk); 1574 struct kcm_mux *mux = kcm->mux; 1575 struct kcm_psock *psock; 1576 struct socket *csock; 1577 struct sock *csk; 1578 int err; 1579 1580 csock = sockfd_lookup(info->fd, &err); 1581 if (!csock) 1582 return -ENOENT; 1583 1584 csk = csock->sk; 1585 if (!csk) { 1586 err = -EINVAL; 1587 goto out; 1588 } 1589 1590 err = -ENOENT; 1591 1592 spin_lock_bh(&mux->lock); 1593 1594 list_for_each_entry(psock, &mux->psocks, psock_list) { 1595 if (psock->sk != csk) 1596 continue; 1597 1598 /* Found the matching psock */ 1599 1600 if (psock->unattaching || WARN_ON(psock->done)) { 1601 err = -EALREADY; 1602 break; 1603 } 1604 1605 psock->unattaching = 1; 1606 1607 spin_unlock_bh(&mux->lock); 1608 1609 /* Lower socket lock should already be held */ 1610 kcm_unattach(psock); 1611 1612 err = 0; 1613 goto out; 1614 } 1615 1616 spin_unlock_bh(&mux->lock); 1617 1618 out: 1619 fput(csock->file); 1620 return err; 1621 } 1622 1623 static struct proto kcm_proto = { 1624 .name = "KCM", 1625 .owner = THIS_MODULE, 1626 .obj_size = sizeof(struct kcm_sock), 1627 }; 1628 1629 /* Clone a kcm socket. */ 1630 static int kcm_clone(struct socket *osock, struct kcm_clone *info, 1631 struct socket **newsockp) 1632 { 1633 struct socket *newsock; 1634 struct sock *newsk; 1635 struct file *newfile; 1636 int err, newfd; 1637 1638 err = -ENFILE; 1639 newsock = sock_alloc(); 1640 if (!newsock) 1641 goto out; 1642 1643 newsock->type = osock->type; 1644 newsock->ops = osock->ops; 1645 1646 __module_get(newsock->ops->owner); 1647 1648 newfd = get_unused_fd_flags(0); 1649 if (unlikely(newfd < 0)) { 1650 err = newfd; 1651 goto out_fd_fail; 1652 } 1653 1654 newfile = sock_alloc_file(newsock, 0, osock->sk->sk_prot_creator->name); 1655 if (unlikely(IS_ERR(newfile))) { 1656 err = PTR_ERR(newfile); 1657 goto out_sock_alloc_fail; 1658 } 1659 1660 newsk = sk_alloc(sock_net(osock->sk), PF_KCM, GFP_KERNEL, 1661 &kcm_proto, true); 1662 if (!newsk) { 1663 err = -ENOMEM; 1664 goto out_sk_alloc_fail; 1665 } 1666 1667 sock_init_data(newsock, newsk); 1668 init_kcm_sock(kcm_sk(newsk), kcm_sk(osock->sk)->mux); 1669 1670 fd_install(newfd, newfile); 1671 *newsockp = newsock; 1672 info->fd = newfd; 1673 1674 return 0; 1675 1676 out_sk_alloc_fail: 1677 fput(newfile); 1678 out_sock_alloc_fail: 1679 put_unused_fd(newfd); 1680 out_fd_fail: 1681 sock_release(newsock); 1682 out: 1683 return err; 1684 } 1685 1686 static int kcm_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg) 1687 { 1688 int err; 1689 1690 switch (cmd) { 1691 case SIOCKCMATTACH: { 1692 struct kcm_attach info; 1693 1694 if (copy_from_user(&info, (void __user *)arg, sizeof(info))) 1695 err = -EFAULT; 1696 1697 err = kcm_attach_ioctl(sock, &info); 1698 1699 break; 1700 } 1701 case SIOCKCMUNATTACH: { 1702 struct kcm_unattach info; 1703 1704 if (copy_from_user(&info, (void __user *)arg, sizeof(info))) 1705 err = -EFAULT; 1706 1707 err = kcm_unattach_ioctl(sock, &info); 1708 1709 break; 1710 } 1711 case SIOCKCMCLONE: { 1712 struct kcm_clone info; 1713 struct socket *newsock = NULL; 1714 1715 if (copy_from_user(&info, (void __user *)arg, sizeof(info))) 1716 err = -EFAULT; 1717 1718 err = kcm_clone(sock, &info, &newsock); 1719 1720 if (!err) { 1721 if (copy_to_user((void __user *)arg, &info, 1722 sizeof(info))) { 1723 err = -EFAULT; 1724 sock_release(newsock); 1725 } 1726 } 1727 1728 break; 1729 } 1730 default: 1731 err = -ENOIOCTLCMD; 1732 break; 1733 } 1734 1735 return err; 1736 } 1737 1738 static void free_mux(struct rcu_head *rcu) 1739 { 1740 struct kcm_mux *mux = container_of(rcu, 1741 struct kcm_mux, rcu); 1742 1743 kmem_cache_free(kcm_muxp, mux); 1744 } 1745 1746 static void release_mux(struct kcm_mux *mux) 1747 { 1748 struct kcm_net *knet = mux->knet; 1749 struct kcm_psock *psock, *tmp_psock; 1750 1751 /* Release psocks */ 1752 list_for_each_entry_safe(psock, tmp_psock, 1753 &mux->psocks, psock_list) { 1754 if (!WARN_ON(psock->unattaching)) 1755 kcm_unattach(psock); 1756 } 1757 1758 if (WARN_ON(mux->psocks_cnt)) 1759 return; 1760 1761 __skb_queue_purge(&mux->rx_hold_queue); 1762 1763 mutex_lock(&knet->mutex); 1764 aggregate_mux_stats(&mux->stats, &knet->aggregate_mux_stats); 1765 aggregate_psock_stats(&mux->aggregate_psock_stats, 1766 &knet->aggregate_psock_stats); 1767 aggregate_strp_stats(&mux->aggregate_strp_stats, 1768 &knet->aggregate_strp_stats); 1769 list_del_rcu(&mux->kcm_mux_list); 1770 knet->count--; 1771 mutex_unlock(&knet->mutex); 1772 1773 call_rcu(&mux->rcu, free_mux); 1774 } 1775 1776 static void kcm_done(struct kcm_sock *kcm) 1777 { 1778 struct kcm_mux *mux = kcm->mux; 1779 struct sock *sk = &kcm->sk; 1780 int socks_cnt; 1781 1782 spin_lock_bh(&mux->rx_lock); 1783 if (kcm->rx_psock) { 1784 /* Cleanup in unreserve_rx_kcm */ 1785 WARN_ON(kcm->done); 1786 kcm->rx_disabled = 1; 1787 kcm->done = 1; 1788 spin_unlock_bh(&mux->rx_lock); 1789 return; 1790 } 1791 1792 if (kcm->rx_wait) { 1793 list_del(&kcm->wait_rx_list); 1794 kcm->rx_wait = false; 1795 } 1796 /* Move any pending receive messages to other kcm sockets */ 1797 requeue_rx_msgs(mux, &sk->sk_receive_queue); 1798 1799 spin_unlock_bh(&mux->rx_lock); 1800 1801 if (WARN_ON(sk_rmem_alloc_get(sk))) 1802 return; 1803 1804 /* Detach from MUX */ 1805 spin_lock_bh(&mux->lock); 1806 1807 list_del(&kcm->kcm_sock_list); 1808 mux->kcm_socks_cnt--; 1809 socks_cnt = mux->kcm_socks_cnt; 1810 1811 spin_unlock_bh(&mux->lock); 1812 1813 if (!socks_cnt) { 1814 /* We are done with the mux now. */ 1815 release_mux(mux); 1816 } 1817 1818 WARN_ON(kcm->rx_wait); 1819 1820 sock_put(&kcm->sk); 1821 } 1822 1823 /* Called by kcm_release to close a KCM socket. 1824 * If this is the last KCM socket on the MUX, destroy the MUX. 1825 */ 1826 static int kcm_release(struct socket *sock) 1827 { 1828 struct sock *sk = sock->sk; 1829 struct kcm_sock *kcm; 1830 struct kcm_mux *mux; 1831 struct kcm_psock *psock; 1832 1833 if (!sk) 1834 return 0; 1835 1836 kcm = kcm_sk(sk); 1837 mux = kcm->mux; 1838 1839 sock_orphan(sk); 1840 kfree_skb(kcm->seq_skb); 1841 1842 lock_sock(sk); 1843 /* Purge queue under lock to avoid race condition with tx_work trying 1844 * to act when queue is nonempty. If tx_work runs after this point 1845 * it will just return. 1846 */ 1847 __skb_queue_purge(&sk->sk_write_queue); 1848 1849 /* Set tx_stopped. This is checked when psock is bound to a kcm and we 1850 * get a writespace callback. This prevents further work being queued 1851 * from the callback (unbinding the psock occurs after canceling work. 1852 */ 1853 kcm->tx_stopped = 1; 1854 1855 release_sock(sk); 1856 1857 spin_lock_bh(&mux->lock); 1858 if (kcm->tx_wait) { 1859 /* Take of tx_wait list, after this point there should be no way 1860 * that a psock will be assigned to this kcm. 1861 */ 1862 list_del(&kcm->wait_psock_list); 1863 kcm->tx_wait = false; 1864 } 1865 spin_unlock_bh(&mux->lock); 1866 1867 /* Cancel work. After this point there should be no outside references 1868 * to the kcm socket. 1869 */ 1870 cancel_work_sync(&kcm->tx_work); 1871 1872 lock_sock(sk); 1873 psock = kcm->tx_psock; 1874 if (psock) { 1875 /* A psock was reserved, so we need to kill it since it 1876 * may already have some bytes queued from a message. We 1877 * need to do this after removing kcm from tx_wait list. 1878 */ 1879 kcm_abort_tx_psock(psock, EPIPE, false); 1880 unreserve_psock(kcm); 1881 } 1882 release_sock(sk); 1883 1884 WARN_ON(kcm->tx_wait); 1885 WARN_ON(kcm->tx_psock); 1886 1887 sock->sk = NULL; 1888 1889 kcm_done(kcm); 1890 1891 return 0; 1892 } 1893 1894 static const struct proto_ops kcm_dgram_ops = { 1895 .family = PF_KCM, 1896 .owner = THIS_MODULE, 1897 .release = kcm_release, 1898 .bind = sock_no_bind, 1899 .connect = sock_no_connect, 1900 .socketpair = sock_no_socketpair, 1901 .accept = sock_no_accept, 1902 .getname = sock_no_getname, 1903 .poll = datagram_poll, 1904 .ioctl = kcm_ioctl, 1905 .listen = sock_no_listen, 1906 .shutdown = sock_no_shutdown, 1907 .setsockopt = kcm_setsockopt, 1908 .getsockopt = kcm_getsockopt, 1909 .sendmsg = kcm_sendmsg, 1910 .recvmsg = kcm_recvmsg, 1911 .mmap = sock_no_mmap, 1912 .sendpage = kcm_sendpage, 1913 }; 1914 1915 static const struct proto_ops kcm_seqpacket_ops = { 1916 .family = PF_KCM, 1917 .owner = THIS_MODULE, 1918 .release = kcm_release, 1919 .bind = sock_no_bind, 1920 .connect = sock_no_connect, 1921 .socketpair = sock_no_socketpair, 1922 .accept = sock_no_accept, 1923 .getname = sock_no_getname, 1924 .poll = datagram_poll, 1925 .ioctl = kcm_ioctl, 1926 .listen = sock_no_listen, 1927 .shutdown = sock_no_shutdown, 1928 .setsockopt = kcm_setsockopt, 1929 .getsockopt = kcm_getsockopt, 1930 .sendmsg = kcm_sendmsg, 1931 .recvmsg = kcm_recvmsg, 1932 .mmap = sock_no_mmap, 1933 .sendpage = kcm_sendpage, 1934 .splice_read = kcm_splice_read, 1935 }; 1936 1937 /* Create proto operation for kcm sockets */ 1938 static int kcm_create(struct net *net, struct socket *sock, 1939 int protocol, int kern) 1940 { 1941 struct kcm_net *knet = net_generic(net, kcm_net_id); 1942 struct sock *sk; 1943 struct kcm_mux *mux; 1944 1945 switch (sock->type) { 1946 case SOCK_DGRAM: 1947 sock->ops = &kcm_dgram_ops; 1948 break; 1949 case SOCK_SEQPACKET: 1950 sock->ops = &kcm_seqpacket_ops; 1951 break; 1952 default: 1953 return -ESOCKTNOSUPPORT; 1954 } 1955 1956 if (protocol != KCMPROTO_CONNECTED) 1957 return -EPROTONOSUPPORT; 1958 1959 sk = sk_alloc(net, PF_KCM, GFP_KERNEL, &kcm_proto, kern); 1960 if (!sk) 1961 return -ENOMEM; 1962 1963 /* Allocate a kcm mux, shared between KCM sockets */ 1964 mux = kmem_cache_zalloc(kcm_muxp, GFP_KERNEL); 1965 if (!mux) { 1966 sk_free(sk); 1967 return -ENOMEM; 1968 } 1969 1970 spin_lock_init(&mux->lock); 1971 spin_lock_init(&mux->rx_lock); 1972 INIT_LIST_HEAD(&mux->kcm_socks); 1973 INIT_LIST_HEAD(&mux->kcm_rx_waiters); 1974 INIT_LIST_HEAD(&mux->kcm_tx_waiters); 1975 1976 INIT_LIST_HEAD(&mux->psocks); 1977 INIT_LIST_HEAD(&mux->psocks_ready); 1978 INIT_LIST_HEAD(&mux->psocks_avail); 1979 1980 mux->knet = knet; 1981 1982 /* Add new MUX to list */ 1983 mutex_lock(&knet->mutex); 1984 list_add_rcu(&mux->kcm_mux_list, &knet->mux_list); 1985 knet->count++; 1986 mutex_unlock(&knet->mutex); 1987 1988 skb_queue_head_init(&mux->rx_hold_queue); 1989 1990 /* Init KCM socket */ 1991 sock_init_data(sock, sk); 1992 init_kcm_sock(kcm_sk(sk), mux); 1993 1994 return 0; 1995 } 1996 1997 static struct net_proto_family kcm_family_ops = { 1998 .family = PF_KCM, 1999 .create = kcm_create, 2000 .owner = THIS_MODULE, 2001 }; 2002 2003 static __net_init int kcm_init_net(struct net *net) 2004 { 2005 struct kcm_net *knet = net_generic(net, kcm_net_id); 2006 2007 INIT_LIST_HEAD_RCU(&knet->mux_list); 2008 mutex_init(&knet->mutex); 2009 2010 return 0; 2011 } 2012 2013 static __net_exit void kcm_exit_net(struct net *net) 2014 { 2015 struct kcm_net *knet = net_generic(net, kcm_net_id); 2016 2017 /* All KCM sockets should be closed at this point, which should mean 2018 * that all multiplexors and psocks have been destroyed. 2019 */ 2020 WARN_ON(!list_empty(&knet->mux_list)); 2021 } 2022 2023 static struct pernet_operations kcm_net_ops = { 2024 .init = kcm_init_net, 2025 .exit = kcm_exit_net, 2026 .id = &kcm_net_id, 2027 .size = sizeof(struct kcm_net), 2028 }; 2029 2030 static int __init kcm_init(void) 2031 { 2032 int err = -ENOMEM; 2033 2034 kcm_muxp = kmem_cache_create("kcm_mux_cache", 2035 sizeof(struct kcm_mux), 0, 2036 SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL); 2037 if (!kcm_muxp) 2038 goto fail; 2039 2040 kcm_psockp = kmem_cache_create("kcm_psock_cache", 2041 sizeof(struct kcm_psock), 0, 2042 SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL); 2043 if (!kcm_psockp) 2044 goto fail; 2045 2046 kcm_wq = create_singlethread_workqueue("kkcmd"); 2047 if (!kcm_wq) 2048 goto fail; 2049 2050 err = proto_register(&kcm_proto, 1); 2051 if (err) 2052 goto fail; 2053 2054 err = sock_register(&kcm_family_ops); 2055 if (err) 2056 goto sock_register_fail; 2057 2058 err = register_pernet_device(&kcm_net_ops); 2059 if (err) 2060 goto net_ops_fail; 2061 2062 err = kcm_proc_init(); 2063 if (err) 2064 goto proc_init_fail; 2065 2066 return 0; 2067 2068 proc_init_fail: 2069 unregister_pernet_device(&kcm_net_ops); 2070 2071 net_ops_fail: 2072 sock_unregister(PF_KCM); 2073 2074 sock_register_fail: 2075 proto_unregister(&kcm_proto); 2076 2077 fail: 2078 kmem_cache_destroy(kcm_muxp); 2079 kmem_cache_destroy(kcm_psockp); 2080 2081 if (kcm_wq) 2082 destroy_workqueue(kcm_wq); 2083 2084 return err; 2085 } 2086 2087 static void __exit kcm_exit(void) 2088 { 2089 kcm_proc_exit(); 2090 unregister_pernet_device(&kcm_net_ops); 2091 sock_unregister(PF_KCM); 2092 proto_unregister(&kcm_proto); 2093 destroy_workqueue(kcm_wq); 2094 2095 kmem_cache_destroy(kcm_muxp); 2096 kmem_cache_destroy(kcm_psockp); 2097 } 2098 2099 module_init(kcm_init); 2100 module_exit(kcm_exit); 2101 2102 MODULE_LICENSE("GPL"); 2103 MODULE_ALIAS_NETPROTO(PF_KCM); 2104 2105