1 // SPDX-License-Identifier: GPL-2.0 2 #include <linux/kernel.h> 3 #include <linux/errno.h> 4 #include <linux/fs.h> 5 #include <linux/file.h> 6 #include <linux/mm.h> 7 #include <linux/slab.h> 8 #include <linux/nospec.h> 9 #include <linux/hugetlb.h> 10 #include <linux/compat.h> 11 #include <linux/io_uring.h> 12 13 #include <uapi/linux/io_uring.h> 14 15 #include "io_uring.h" 16 #include "openclose.h" 17 #include "rsrc.h" 18 19 struct io_rsrc_update { 20 struct file *file; 21 u64 arg; 22 u32 nr_args; 23 u32 offset; 24 }; 25 26 static void io_rsrc_buf_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc); 27 static void io_rsrc_file_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc); 28 static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov, 29 struct io_mapped_ubuf **pimu, 30 struct page **last_hpage); 31 32 /* only define max */ 33 #define IORING_MAX_FIXED_FILES (1U << 20) 34 #define IORING_MAX_REG_BUFFERS (1U << 14) 35 36 static const struct io_mapped_ubuf dummy_ubuf = { 37 /* set invalid range, so io_import_fixed() fails meeting it */ 38 .ubuf = -1UL, 39 .ubuf_end = 0, 40 }; 41 42 int __io_account_mem(struct user_struct *user, unsigned long nr_pages) 43 { 44 unsigned long page_limit, cur_pages, new_pages; 45 46 if (!nr_pages) 47 return 0; 48 49 /* Don't allow more pages than we can safely lock */ 50 page_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; 51 52 cur_pages = atomic_long_read(&user->locked_vm); 53 do { 54 new_pages = cur_pages + nr_pages; 55 if (new_pages > page_limit) 56 return -ENOMEM; 57 } while (!atomic_long_try_cmpxchg(&user->locked_vm, 58 &cur_pages, new_pages)); 59 return 0; 60 } 61 62 static void io_unaccount_mem(struct io_ring_ctx *ctx, unsigned long nr_pages) 63 { 64 if (ctx->user) 65 __io_unaccount_mem(ctx->user, nr_pages); 66 67 if (ctx->mm_account) 68 atomic64_sub(nr_pages, &ctx->mm_account->pinned_vm); 69 } 70 71 static int io_account_mem(struct io_ring_ctx *ctx, unsigned long nr_pages) 72 { 73 int ret; 74 75 if (ctx->user) { 76 ret = __io_account_mem(ctx->user, nr_pages); 77 if (ret) 78 return ret; 79 } 80 81 if (ctx->mm_account) 82 atomic64_add(nr_pages, &ctx->mm_account->pinned_vm); 83 84 return 0; 85 } 86 87 static int io_copy_iov(struct io_ring_ctx *ctx, struct iovec *dst, 88 void __user *arg, unsigned index) 89 { 90 struct iovec __user *src; 91 92 #ifdef CONFIG_COMPAT 93 if (ctx->compat) { 94 struct compat_iovec __user *ciovs; 95 struct compat_iovec ciov; 96 97 ciovs = (struct compat_iovec __user *) arg; 98 if (copy_from_user(&ciov, &ciovs[index], sizeof(ciov))) 99 return -EFAULT; 100 101 dst->iov_base = u64_to_user_ptr((u64)ciov.iov_base); 102 dst->iov_len = ciov.iov_len; 103 return 0; 104 } 105 #endif 106 src = (struct iovec __user *) arg; 107 if (copy_from_user(dst, &src[index], sizeof(*dst))) 108 return -EFAULT; 109 return 0; 110 } 111 112 static int io_buffer_validate(struct iovec *iov) 113 { 114 unsigned long tmp, acct_len = iov->iov_len + (PAGE_SIZE - 1); 115 116 /* 117 * Don't impose further limits on the size and buffer 118 * constraints here, we'll -EINVAL later when IO is 119 * submitted if they are wrong. 120 */ 121 if (!iov->iov_base) 122 return iov->iov_len ? -EFAULT : 0; 123 if (!iov->iov_len) 124 return -EFAULT; 125 126 /* arbitrary limit, but we need something */ 127 if (iov->iov_len > SZ_1G) 128 return -EFAULT; 129 130 if (check_add_overflow((unsigned long)iov->iov_base, acct_len, &tmp)) 131 return -EOVERFLOW; 132 133 return 0; 134 } 135 136 static void io_buffer_unmap(struct io_ring_ctx *ctx, struct io_mapped_ubuf **slot) 137 { 138 struct io_mapped_ubuf *imu = *slot; 139 unsigned int i; 140 141 if (imu != &dummy_ubuf) { 142 for (i = 0; i < imu->nr_bvecs; i++) 143 unpin_user_page(imu->bvec[i].bv_page); 144 if (imu->acct_pages) 145 io_unaccount_mem(ctx, imu->acct_pages); 146 kvfree(imu); 147 } 148 *slot = NULL; 149 } 150 151 static void io_rsrc_put_work(struct io_rsrc_node *node) 152 { 153 struct io_rsrc_put *prsrc = &node->item; 154 155 if (prsrc->tag) 156 io_post_aux_cqe(node->ctx, prsrc->tag, 0, 0); 157 158 switch (node->type) { 159 case IORING_RSRC_FILE: 160 io_rsrc_file_put(node->ctx, prsrc); 161 break; 162 case IORING_RSRC_BUFFER: 163 io_rsrc_buf_put(node->ctx, prsrc); 164 break; 165 default: 166 WARN_ON_ONCE(1); 167 break; 168 } 169 } 170 171 void io_rsrc_node_destroy(struct io_ring_ctx *ctx, struct io_rsrc_node *node) 172 { 173 if (!io_alloc_cache_put(&ctx->rsrc_node_cache, &node->cache)) 174 kfree(node); 175 } 176 177 void io_rsrc_node_ref_zero(struct io_rsrc_node *node) 178 __must_hold(&node->ctx->uring_lock) 179 { 180 struct io_ring_ctx *ctx = node->ctx; 181 182 while (!list_empty(&ctx->rsrc_ref_list)) { 183 node = list_first_entry(&ctx->rsrc_ref_list, 184 struct io_rsrc_node, node); 185 /* recycle ref nodes in order */ 186 if (node->refs) 187 break; 188 list_del(&node->node); 189 190 if (likely(!node->empty)) 191 io_rsrc_put_work(node); 192 io_rsrc_node_destroy(ctx, node); 193 } 194 if (list_empty(&ctx->rsrc_ref_list) && unlikely(ctx->rsrc_quiesce)) 195 wake_up_all(&ctx->rsrc_quiesce_wq); 196 } 197 198 struct io_rsrc_node *io_rsrc_node_alloc(struct io_ring_ctx *ctx) 199 { 200 struct io_rsrc_node *ref_node; 201 struct io_cache_entry *entry; 202 203 entry = io_alloc_cache_get(&ctx->rsrc_node_cache); 204 if (entry) { 205 ref_node = container_of(entry, struct io_rsrc_node, cache); 206 } else { 207 ref_node = kzalloc(sizeof(*ref_node), GFP_KERNEL); 208 if (!ref_node) 209 return NULL; 210 } 211 212 ref_node->ctx = ctx; 213 ref_node->empty = 0; 214 ref_node->refs = 1; 215 return ref_node; 216 } 217 218 __cold static int io_rsrc_ref_quiesce(struct io_rsrc_data *data, 219 struct io_ring_ctx *ctx) 220 { 221 struct io_rsrc_node *backup; 222 DEFINE_WAIT(we); 223 int ret; 224 225 /* As We may drop ->uring_lock, other task may have started quiesce */ 226 if (data->quiesce) 227 return -ENXIO; 228 229 backup = io_rsrc_node_alloc(ctx); 230 if (!backup) 231 return -ENOMEM; 232 ctx->rsrc_node->empty = true; 233 ctx->rsrc_node->type = -1; 234 list_add_tail(&ctx->rsrc_node->node, &ctx->rsrc_ref_list); 235 io_put_rsrc_node(ctx, ctx->rsrc_node); 236 ctx->rsrc_node = backup; 237 238 if (list_empty(&ctx->rsrc_ref_list)) 239 return 0; 240 241 if (ctx->flags & IORING_SETUP_DEFER_TASKRUN) { 242 atomic_set(&ctx->cq_wait_nr, 1); 243 smp_mb(); 244 } 245 246 ctx->rsrc_quiesce++; 247 data->quiesce = true; 248 do { 249 prepare_to_wait(&ctx->rsrc_quiesce_wq, &we, TASK_INTERRUPTIBLE); 250 mutex_unlock(&ctx->uring_lock); 251 252 ret = io_run_task_work_sig(ctx); 253 if (ret < 0) { 254 mutex_lock(&ctx->uring_lock); 255 if (list_empty(&ctx->rsrc_ref_list)) 256 ret = 0; 257 break; 258 } 259 260 schedule(); 261 __set_current_state(TASK_RUNNING); 262 mutex_lock(&ctx->uring_lock); 263 ret = 0; 264 } while (!list_empty(&ctx->rsrc_ref_list)); 265 266 finish_wait(&ctx->rsrc_quiesce_wq, &we); 267 data->quiesce = false; 268 ctx->rsrc_quiesce--; 269 270 if (ctx->flags & IORING_SETUP_DEFER_TASKRUN) { 271 atomic_set(&ctx->cq_wait_nr, 0); 272 smp_mb(); 273 } 274 return ret; 275 } 276 277 static void io_free_page_table(void **table, size_t size) 278 { 279 unsigned i, nr_tables = DIV_ROUND_UP(size, PAGE_SIZE); 280 281 for (i = 0; i < nr_tables; i++) 282 kfree(table[i]); 283 kfree(table); 284 } 285 286 static void io_rsrc_data_free(struct io_rsrc_data *data) 287 { 288 size_t size = data->nr * sizeof(data->tags[0][0]); 289 290 if (data->tags) 291 io_free_page_table((void **)data->tags, size); 292 kfree(data); 293 } 294 295 static __cold void **io_alloc_page_table(size_t size) 296 { 297 unsigned i, nr_tables = DIV_ROUND_UP(size, PAGE_SIZE); 298 size_t init_size = size; 299 void **table; 300 301 table = kcalloc(nr_tables, sizeof(*table), GFP_KERNEL_ACCOUNT); 302 if (!table) 303 return NULL; 304 305 for (i = 0; i < nr_tables; i++) { 306 unsigned int this_size = min_t(size_t, size, PAGE_SIZE); 307 308 table[i] = kzalloc(this_size, GFP_KERNEL_ACCOUNT); 309 if (!table[i]) { 310 io_free_page_table(table, init_size); 311 return NULL; 312 } 313 size -= this_size; 314 } 315 return table; 316 } 317 318 __cold static int io_rsrc_data_alloc(struct io_ring_ctx *ctx, int type, 319 u64 __user *utags, 320 unsigned nr, struct io_rsrc_data **pdata) 321 { 322 struct io_rsrc_data *data; 323 int ret = 0; 324 unsigned i; 325 326 data = kzalloc(sizeof(*data), GFP_KERNEL); 327 if (!data) 328 return -ENOMEM; 329 data->tags = (u64 **)io_alloc_page_table(nr * sizeof(data->tags[0][0])); 330 if (!data->tags) { 331 kfree(data); 332 return -ENOMEM; 333 } 334 335 data->nr = nr; 336 data->ctx = ctx; 337 data->rsrc_type = type; 338 if (utags) { 339 ret = -EFAULT; 340 for (i = 0; i < nr; i++) { 341 u64 *tag_slot = io_get_tag_slot(data, i); 342 343 if (copy_from_user(tag_slot, &utags[i], 344 sizeof(*tag_slot))) 345 goto fail; 346 } 347 } 348 *pdata = data; 349 return 0; 350 fail: 351 io_rsrc_data_free(data); 352 return ret; 353 } 354 355 static int __io_sqe_files_update(struct io_ring_ctx *ctx, 356 struct io_uring_rsrc_update2 *up, 357 unsigned nr_args) 358 { 359 u64 __user *tags = u64_to_user_ptr(up->tags); 360 __s32 __user *fds = u64_to_user_ptr(up->data); 361 struct io_rsrc_data *data = ctx->file_data; 362 struct io_fixed_file *file_slot; 363 int fd, i, err = 0; 364 unsigned int done; 365 366 if (!ctx->file_data) 367 return -ENXIO; 368 if (up->offset + nr_args > ctx->nr_user_files) 369 return -EINVAL; 370 371 for (done = 0; done < nr_args; done++) { 372 u64 tag = 0; 373 374 if ((tags && copy_from_user(&tag, &tags[done], sizeof(tag))) || 375 copy_from_user(&fd, &fds[done], sizeof(fd))) { 376 err = -EFAULT; 377 break; 378 } 379 if ((fd == IORING_REGISTER_FILES_SKIP || fd == -1) && tag) { 380 err = -EINVAL; 381 break; 382 } 383 if (fd == IORING_REGISTER_FILES_SKIP) 384 continue; 385 386 i = array_index_nospec(up->offset + done, ctx->nr_user_files); 387 file_slot = io_fixed_file_slot(&ctx->file_table, i); 388 389 if (file_slot->file_ptr) { 390 err = io_queue_rsrc_removal(data, i, 391 io_slot_file(file_slot)); 392 if (err) 393 break; 394 file_slot->file_ptr = 0; 395 io_file_bitmap_clear(&ctx->file_table, i); 396 } 397 if (fd != -1) { 398 struct file *file = fget(fd); 399 400 if (!file) { 401 err = -EBADF; 402 break; 403 } 404 /* 405 * Don't allow io_uring instances to be registered. If 406 * UNIX isn't enabled, then this causes a reference 407 * cycle and this instance can never get freed. If UNIX 408 * is enabled we'll handle it just fine, but there's 409 * still no point in allowing a ring fd as it doesn't 410 * support regular read/write anyway. 411 */ 412 if (io_is_uring_fops(file)) { 413 fput(file); 414 err = -EBADF; 415 break; 416 } 417 err = io_scm_file_account(ctx, file); 418 if (err) { 419 fput(file); 420 break; 421 } 422 *io_get_tag_slot(data, i) = tag; 423 io_fixed_file_set(file_slot, file); 424 io_file_bitmap_set(&ctx->file_table, i); 425 } 426 } 427 return done ? done : err; 428 } 429 430 static int __io_sqe_buffers_update(struct io_ring_ctx *ctx, 431 struct io_uring_rsrc_update2 *up, 432 unsigned int nr_args) 433 { 434 u64 __user *tags = u64_to_user_ptr(up->tags); 435 struct iovec iov, __user *iovs = u64_to_user_ptr(up->data); 436 struct page *last_hpage = NULL; 437 __u32 done; 438 int i, err; 439 440 if (!ctx->buf_data) 441 return -ENXIO; 442 if (up->offset + nr_args > ctx->nr_user_bufs) 443 return -EINVAL; 444 445 for (done = 0; done < nr_args; done++) { 446 struct io_mapped_ubuf *imu; 447 u64 tag = 0; 448 449 err = io_copy_iov(ctx, &iov, iovs, done); 450 if (err) 451 break; 452 if (tags && copy_from_user(&tag, &tags[done], sizeof(tag))) { 453 err = -EFAULT; 454 break; 455 } 456 err = io_buffer_validate(&iov); 457 if (err) 458 break; 459 if (!iov.iov_base && tag) { 460 err = -EINVAL; 461 break; 462 } 463 err = io_sqe_buffer_register(ctx, &iov, &imu, &last_hpage); 464 if (err) 465 break; 466 467 i = array_index_nospec(up->offset + done, ctx->nr_user_bufs); 468 if (ctx->user_bufs[i] != &dummy_ubuf) { 469 err = io_queue_rsrc_removal(ctx->buf_data, i, 470 ctx->user_bufs[i]); 471 if (unlikely(err)) { 472 io_buffer_unmap(ctx, &imu); 473 break; 474 } 475 ctx->user_bufs[i] = (struct io_mapped_ubuf *)&dummy_ubuf; 476 } 477 478 ctx->user_bufs[i] = imu; 479 *io_get_tag_slot(ctx->buf_data, i) = tag; 480 } 481 return done ? done : err; 482 } 483 484 static int __io_register_rsrc_update(struct io_ring_ctx *ctx, unsigned type, 485 struct io_uring_rsrc_update2 *up, 486 unsigned nr_args) 487 { 488 __u32 tmp; 489 490 lockdep_assert_held(&ctx->uring_lock); 491 492 if (check_add_overflow(up->offset, nr_args, &tmp)) 493 return -EOVERFLOW; 494 495 switch (type) { 496 case IORING_RSRC_FILE: 497 return __io_sqe_files_update(ctx, up, nr_args); 498 case IORING_RSRC_BUFFER: 499 return __io_sqe_buffers_update(ctx, up, nr_args); 500 } 501 return -EINVAL; 502 } 503 504 int io_register_files_update(struct io_ring_ctx *ctx, void __user *arg, 505 unsigned nr_args) 506 { 507 struct io_uring_rsrc_update2 up; 508 509 if (!nr_args) 510 return -EINVAL; 511 memset(&up, 0, sizeof(up)); 512 if (copy_from_user(&up, arg, sizeof(struct io_uring_rsrc_update))) 513 return -EFAULT; 514 if (up.resv || up.resv2) 515 return -EINVAL; 516 return __io_register_rsrc_update(ctx, IORING_RSRC_FILE, &up, nr_args); 517 } 518 519 int io_register_rsrc_update(struct io_ring_ctx *ctx, void __user *arg, 520 unsigned size, unsigned type) 521 { 522 struct io_uring_rsrc_update2 up; 523 524 if (size != sizeof(up)) 525 return -EINVAL; 526 if (copy_from_user(&up, arg, sizeof(up))) 527 return -EFAULT; 528 if (!up.nr || up.resv || up.resv2) 529 return -EINVAL; 530 return __io_register_rsrc_update(ctx, type, &up, up.nr); 531 } 532 533 __cold int io_register_rsrc(struct io_ring_ctx *ctx, void __user *arg, 534 unsigned int size, unsigned int type) 535 { 536 struct io_uring_rsrc_register rr; 537 538 /* keep it extendible */ 539 if (size != sizeof(rr)) 540 return -EINVAL; 541 542 memset(&rr, 0, sizeof(rr)); 543 if (copy_from_user(&rr, arg, size)) 544 return -EFAULT; 545 if (!rr.nr || rr.resv2) 546 return -EINVAL; 547 if (rr.flags & ~IORING_RSRC_REGISTER_SPARSE) 548 return -EINVAL; 549 550 switch (type) { 551 case IORING_RSRC_FILE: 552 if (rr.flags & IORING_RSRC_REGISTER_SPARSE && rr.data) 553 break; 554 return io_sqe_files_register(ctx, u64_to_user_ptr(rr.data), 555 rr.nr, u64_to_user_ptr(rr.tags)); 556 case IORING_RSRC_BUFFER: 557 if (rr.flags & IORING_RSRC_REGISTER_SPARSE && rr.data) 558 break; 559 return io_sqe_buffers_register(ctx, u64_to_user_ptr(rr.data), 560 rr.nr, u64_to_user_ptr(rr.tags)); 561 } 562 return -EINVAL; 563 } 564 565 int io_files_update_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) 566 { 567 struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update); 568 569 if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT))) 570 return -EINVAL; 571 if (sqe->rw_flags || sqe->splice_fd_in) 572 return -EINVAL; 573 574 up->offset = READ_ONCE(sqe->off); 575 up->nr_args = READ_ONCE(sqe->len); 576 if (!up->nr_args) 577 return -EINVAL; 578 up->arg = READ_ONCE(sqe->addr); 579 return 0; 580 } 581 582 static int io_files_update_with_index_alloc(struct io_kiocb *req, 583 unsigned int issue_flags) 584 { 585 struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update); 586 __s32 __user *fds = u64_to_user_ptr(up->arg); 587 unsigned int done; 588 struct file *file; 589 int ret, fd; 590 591 if (!req->ctx->file_data) 592 return -ENXIO; 593 594 for (done = 0; done < up->nr_args; done++) { 595 if (copy_from_user(&fd, &fds[done], sizeof(fd))) { 596 ret = -EFAULT; 597 break; 598 } 599 600 file = fget(fd); 601 if (!file) { 602 ret = -EBADF; 603 break; 604 } 605 ret = io_fixed_fd_install(req, issue_flags, file, 606 IORING_FILE_INDEX_ALLOC); 607 if (ret < 0) 608 break; 609 if (copy_to_user(&fds[done], &ret, sizeof(ret))) { 610 __io_close_fixed(req->ctx, issue_flags, ret); 611 ret = -EFAULT; 612 break; 613 } 614 } 615 616 if (done) 617 return done; 618 return ret; 619 } 620 621 int io_files_update(struct io_kiocb *req, unsigned int issue_flags) 622 { 623 struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update); 624 struct io_ring_ctx *ctx = req->ctx; 625 struct io_uring_rsrc_update2 up2; 626 int ret; 627 628 up2.offset = up->offset; 629 up2.data = up->arg; 630 up2.nr = 0; 631 up2.tags = 0; 632 up2.resv = 0; 633 up2.resv2 = 0; 634 635 if (up->offset == IORING_FILE_INDEX_ALLOC) { 636 ret = io_files_update_with_index_alloc(req, issue_flags); 637 } else { 638 io_ring_submit_lock(ctx, issue_flags); 639 ret = __io_register_rsrc_update(ctx, IORING_RSRC_FILE, 640 &up2, up->nr_args); 641 io_ring_submit_unlock(ctx, issue_flags); 642 } 643 644 if (ret < 0) 645 req_set_fail(req); 646 io_req_set_res(req, ret, 0); 647 return IOU_OK; 648 } 649 650 int io_queue_rsrc_removal(struct io_rsrc_data *data, unsigned idx, void *rsrc) 651 { 652 struct io_ring_ctx *ctx = data->ctx; 653 struct io_rsrc_node *node = ctx->rsrc_node; 654 u64 *tag_slot = io_get_tag_slot(data, idx); 655 656 ctx->rsrc_node = io_rsrc_node_alloc(ctx); 657 if (unlikely(!ctx->rsrc_node)) { 658 ctx->rsrc_node = node; 659 return -ENOMEM; 660 } 661 662 node->item.rsrc = rsrc; 663 node->type = data->rsrc_type; 664 node->item.tag = *tag_slot; 665 *tag_slot = 0; 666 list_add_tail(&node->node, &ctx->rsrc_ref_list); 667 io_put_rsrc_node(ctx, node); 668 return 0; 669 } 670 671 void __io_sqe_files_unregister(struct io_ring_ctx *ctx) 672 { 673 int i; 674 675 for (i = 0; i < ctx->nr_user_files; i++) { 676 struct file *file = io_file_from_index(&ctx->file_table, i); 677 678 /* skip scm accounted files, they'll be freed by ->ring_sock */ 679 if (!file || io_file_need_scm(file)) 680 continue; 681 io_file_bitmap_clear(&ctx->file_table, i); 682 fput(file); 683 } 684 685 #if defined(CONFIG_UNIX) 686 if (ctx->ring_sock) { 687 struct sock *sock = ctx->ring_sock->sk; 688 struct sk_buff *skb; 689 690 while ((skb = skb_dequeue(&sock->sk_receive_queue)) != NULL) 691 kfree_skb(skb); 692 } 693 #endif 694 io_free_file_tables(&ctx->file_table); 695 io_file_table_set_alloc_range(ctx, 0, 0); 696 io_rsrc_data_free(ctx->file_data); 697 ctx->file_data = NULL; 698 ctx->nr_user_files = 0; 699 } 700 701 int io_sqe_files_unregister(struct io_ring_ctx *ctx) 702 { 703 unsigned nr = ctx->nr_user_files; 704 int ret; 705 706 if (!ctx->file_data) 707 return -ENXIO; 708 709 /* 710 * Quiesce may unlock ->uring_lock, and while it's not held 711 * prevent new requests using the table. 712 */ 713 ctx->nr_user_files = 0; 714 ret = io_rsrc_ref_quiesce(ctx->file_data, ctx); 715 ctx->nr_user_files = nr; 716 if (!ret) 717 __io_sqe_files_unregister(ctx); 718 return ret; 719 } 720 721 /* 722 * Ensure the UNIX gc is aware of our file set, so we are certain that 723 * the io_uring can be safely unregistered on process exit, even if we have 724 * loops in the file referencing. We account only files that can hold other 725 * files because otherwise they can't form a loop and so are not interesting 726 * for GC. 727 */ 728 int __io_scm_file_account(struct io_ring_ctx *ctx, struct file *file) 729 { 730 #if defined(CONFIG_UNIX) 731 struct sock *sk = ctx->ring_sock->sk; 732 struct sk_buff_head *head = &sk->sk_receive_queue; 733 struct scm_fp_list *fpl; 734 struct sk_buff *skb; 735 736 if (likely(!io_file_need_scm(file))) 737 return 0; 738 739 /* 740 * See if we can merge this file into an existing skb SCM_RIGHTS 741 * file set. If there's no room, fall back to allocating a new skb 742 * and filling it in. 743 */ 744 spin_lock_irq(&head->lock); 745 skb = skb_peek(head); 746 if (skb && UNIXCB(skb).fp->count < SCM_MAX_FD) 747 __skb_unlink(skb, head); 748 else 749 skb = NULL; 750 spin_unlock_irq(&head->lock); 751 752 if (!skb) { 753 fpl = kzalloc(sizeof(*fpl), GFP_KERNEL); 754 if (!fpl) 755 return -ENOMEM; 756 757 skb = alloc_skb(0, GFP_KERNEL); 758 if (!skb) { 759 kfree(fpl); 760 return -ENOMEM; 761 } 762 763 fpl->user = get_uid(current_user()); 764 fpl->max = SCM_MAX_FD; 765 fpl->count = 0; 766 767 UNIXCB(skb).fp = fpl; 768 skb->sk = sk; 769 skb->destructor = io_uring_destruct_scm; 770 refcount_add(skb->truesize, &sk->sk_wmem_alloc); 771 } 772 773 fpl = UNIXCB(skb).fp; 774 fpl->fp[fpl->count++] = get_file(file); 775 unix_inflight(fpl->user, file); 776 skb_queue_head(head, skb); 777 fput(file); 778 #endif 779 return 0; 780 } 781 782 static __cold void io_rsrc_file_scm_put(struct io_ring_ctx *ctx, struct file *file) 783 { 784 #if defined(CONFIG_UNIX) 785 struct sock *sock = ctx->ring_sock->sk; 786 struct sk_buff_head list, *head = &sock->sk_receive_queue; 787 struct sk_buff *skb; 788 int i; 789 790 __skb_queue_head_init(&list); 791 792 /* 793 * Find the skb that holds this file in its SCM_RIGHTS. When found, 794 * remove this entry and rearrange the file array. 795 */ 796 skb = skb_dequeue(head); 797 while (skb) { 798 struct scm_fp_list *fp; 799 800 fp = UNIXCB(skb).fp; 801 for (i = 0; i < fp->count; i++) { 802 int left; 803 804 if (fp->fp[i] != file) 805 continue; 806 807 unix_notinflight(fp->user, fp->fp[i]); 808 left = fp->count - 1 - i; 809 if (left) { 810 memmove(&fp->fp[i], &fp->fp[i + 1], 811 left * sizeof(struct file *)); 812 } 813 fp->count--; 814 if (!fp->count) { 815 kfree_skb(skb); 816 skb = NULL; 817 } else { 818 __skb_queue_tail(&list, skb); 819 } 820 fput(file); 821 file = NULL; 822 break; 823 } 824 825 if (!file) 826 break; 827 828 __skb_queue_tail(&list, skb); 829 830 skb = skb_dequeue(head); 831 } 832 833 if (skb_peek(&list)) { 834 spin_lock_irq(&head->lock); 835 while ((skb = __skb_dequeue(&list)) != NULL) 836 __skb_queue_tail(head, skb); 837 spin_unlock_irq(&head->lock); 838 } 839 #endif 840 } 841 842 static void io_rsrc_file_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc) 843 { 844 struct file *file = prsrc->file; 845 846 if (likely(!io_file_need_scm(file))) 847 fput(file); 848 else 849 io_rsrc_file_scm_put(ctx, file); 850 } 851 852 int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg, 853 unsigned nr_args, u64 __user *tags) 854 { 855 __s32 __user *fds = (__s32 __user *) arg; 856 struct file *file; 857 int fd, ret; 858 unsigned i; 859 860 if (ctx->file_data) 861 return -EBUSY; 862 if (!nr_args) 863 return -EINVAL; 864 if (nr_args > IORING_MAX_FIXED_FILES) 865 return -EMFILE; 866 if (nr_args > rlimit(RLIMIT_NOFILE)) 867 return -EMFILE; 868 ret = io_rsrc_data_alloc(ctx, IORING_RSRC_FILE, tags, nr_args, 869 &ctx->file_data); 870 if (ret) 871 return ret; 872 873 if (!io_alloc_file_tables(&ctx->file_table, nr_args)) { 874 io_rsrc_data_free(ctx->file_data); 875 ctx->file_data = NULL; 876 return -ENOMEM; 877 } 878 879 for (i = 0; i < nr_args; i++, ctx->nr_user_files++) { 880 struct io_fixed_file *file_slot; 881 882 if (fds && copy_from_user(&fd, &fds[i], sizeof(fd))) { 883 ret = -EFAULT; 884 goto fail; 885 } 886 /* allow sparse sets */ 887 if (!fds || fd == -1) { 888 ret = -EINVAL; 889 if (unlikely(*io_get_tag_slot(ctx->file_data, i))) 890 goto fail; 891 continue; 892 } 893 894 file = fget(fd); 895 ret = -EBADF; 896 if (unlikely(!file)) 897 goto fail; 898 899 /* 900 * Don't allow io_uring instances to be registered. If UNIX 901 * isn't enabled, then this causes a reference cycle and this 902 * instance can never get freed. If UNIX is enabled we'll 903 * handle it just fine, but there's still no point in allowing 904 * a ring fd as it doesn't support regular read/write anyway. 905 */ 906 if (io_is_uring_fops(file)) { 907 fput(file); 908 goto fail; 909 } 910 ret = io_scm_file_account(ctx, file); 911 if (ret) { 912 fput(file); 913 goto fail; 914 } 915 file_slot = io_fixed_file_slot(&ctx->file_table, i); 916 io_fixed_file_set(file_slot, file); 917 io_file_bitmap_set(&ctx->file_table, i); 918 } 919 920 /* default it to the whole table */ 921 io_file_table_set_alloc_range(ctx, 0, ctx->nr_user_files); 922 return 0; 923 fail: 924 __io_sqe_files_unregister(ctx); 925 return ret; 926 } 927 928 static void io_rsrc_buf_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc) 929 { 930 io_buffer_unmap(ctx, &prsrc->buf); 931 prsrc->buf = NULL; 932 } 933 934 void __io_sqe_buffers_unregister(struct io_ring_ctx *ctx) 935 { 936 unsigned int i; 937 938 for (i = 0; i < ctx->nr_user_bufs; i++) 939 io_buffer_unmap(ctx, &ctx->user_bufs[i]); 940 kfree(ctx->user_bufs); 941 io_rsrc_data_free(ctx->buf_data); 942 ctx->user_bufs = NULL; 943 ctx->buf_data = NULL; 944 ctx->nr_user_bufs = 0; 945 } 946 947 int io_sqe_buffers_unregister(struct io_ring_ctx *ctx) 948 { 949 unsigned nr = ctx->nr_user_bufs; 950 int ret; 951 952 if (!ctx->buf_data) 953 return -ENXIO; 954 955 /* 956 * Quiesce may unlock ->uring_lock, and while it's not held 957 * prevent new requests using the table. 958 */ 959 ctx->nr_user_bufs = 0; 960 ret = io_rsrc_ref_quiesce(ctx->buf_data, ctx); 961 ctx->nr_user_bufs = nr; 962 if (!ret) 963 __io_sqe_buffers_unregister(ctx); 964 return ret; 965 } 966 967 /* 968 * Not super efficient, but this is just a registration time. And we do cache 969 * the last compound head, so generally we'll only do a full search if we don't 970 * match that one. 971 * 972 * We check if the given compound head page has already been accounted, to 973 * avoid double accounting it. This allows us to account the full size of the 974 * page, not just the constituent pages of a huge page. 975 */ 976 static bool headpage_already_acct(struct io_ring_ctx *ctx, struct page **pages, 977 int nr_pages, struct page *hpage) 978 { 979 int i, j; 980 981 /* check current page array */ 982 for (i = 0; i < nr_pages; i++) { 983 if (!PageCompound(pages[i])) 984 continue; 985 if (compound_head(pages[i]) == hpage) 986 return true; 987 } 988 989 /* check previously registered pages */ 990 for (i = 0; i < ctx->nr_user_bufs; i++) { 991 struct io_mapped_ubuf *imu = ctx->user_bufs[i]; 992 993 for (j = 0; j < imu->nr_bvecs; j++) { 994 if (!PageCompound(imu->bvec[j].bv_page)) 995 continue; 996 if (compound_head(imu->bvec[j].bv_page) == hpage) 997 return true; 998 } 999 } 1000 1001 return false; 1002 } 1003 1004 static int io_buffer_account_pin(struct io_ring_ctx *ctx, struct page **pages, 1005 int nr_pages, struct io_mapped_ubuf *imu, 1006 struct page **last_hpage) 1007 { 1008 int i, ret; 1009 1010 imu->acct_pages = 0; 1011 for (i = 0; i < nr_pages; i++) { 1012 if (!PageCompound(pages[i])) { 1013 imu->acct_pages++; 1014 } else { 1015 struct page *hpage; 1016 1017 hpage = compound_head(pages[i]); 1018 if (hpage == *last_hpage) 1019 continue; 1020 *last_hpage = hpage; 1021 if (headpage_already_acct(ctx, pages, i, hpage)) 1022 continue; 1023 imu->acct_pages += page_size(hpage) >> PAGE_SHIFT; 1024 } 1025 } 1026 1027 if (!imu->acct_pages) 1028 return 0; 1029 1030 ret = io_account_mem(ctx, imu->acct_pages); 1031 if (ret) 1032 imu->acct_pages = 0; 1033 return ret; 1034 } 1035 1036 struct page **io_pin_pages(unsigned long ubuf, unsigned long len, int *npages) 1037 { 1038 unsigned long start, end, nr_pages; 1039 struct page **pages = NULL; 1040 int pret, ret = -ENOMEM; 1041 1042 end = (ubuf + len + PAGE_SIZE - 1) >> PAGE_SHIFT; 1043 start = ubuf >> PAGE_SHIFT; 1044 nr_pages = end - start; 1045 1046 pages = kvmalloc_array(nr_pages, sizeof(struct page *), GFP_KERNEL); 1047 if (!pages) 1048 goto done; 1049 1050 ret = 0; 1051 mmap_read_lock(current->mm); 1052 pret = pin_user_pages(ubuf, nr_pages, FOLL_WRITE | FOLL_LONGTERM, 1053 pages); 1054 if (pret == nr_pages) 1055 *npages = nr_pages; 1056 else 1057 ret = pret < 0 ? pret : -EFAULT; 1058 1059 mmap_read_unlock(current->mm); 1060 if (ret) { 1061 /* if we did partial map, release any pages we did get */ 1062 if (pret > 0) 1063 unpin_user_pages(pages, pret); 1064 goto done; 1065 } 1066 ret = 0; 1067 done: 1068 if (ret < 0) { 1069 kvfree(pages); 1070 pages = ERR_PTR(ret); 1071 } 1072 return pages; 1073 } 1074 1075 static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov, 1076 struct io_mapped_ubuf **pimu, 1077 struct page **last_hpage) 1078 { 1079 struct io_mapped_ubuf *imu = NULL; 1080 struct page **pages = NULL; 1081 unsigned long off; 1082 size_t size; 1083 int ret, nr_pages, i; 1084 struct folio *folio = NULL; 1085 1086 *pimu = (struct io_mapped_ubuf *)&dummy_ubuf; 1087 if (!iov->iov_base) 1088 return 0; 1089 1090 ret = -ENOMEM; 1091 pages = io_pin_pages((unsigned long) iov->iov_base, iov->iov_len, 1092 &nr_pages); 1093 if (IS_ERR(pages)) { 1094 ret = PTR_ERR(pages); 1095 pages = NULL; 1096 goto done; 1097 } 1098 1099 /* If it's a huge page, try to coalesce them into a single bvec entry */ 1100 if (nr_pages > 1) { 1101 folio = page_folio(pages[0]); 1102 for (i = 1; i < nr_pages; i++) { 1103 /* 1104 * Pages must be consecutive and on the same folio for 1105 * this to work 1106 */ 1107 if (page_folio(pages[i]) != folio || 1108 pages[i] != pages[i - 1] + 1) { 1109 folio = NULL; 1110 break; 1111 } 1112 } 1113 if (folio) { 1114 /* 1115 * The pages are bound to the folio, it doesn't 1116 * actually unpin them but drops all but one reference, 1117 * which is usually put down by io_buffer_unmap(). 1118 * Note, needs a better helper. 1119 */ 1120 unpin_user_pages(&pages[1], nr_pages - 1); 1121 nr_pages = 1; 1122 } 1123 } 1124 1125 imu = kvmalloc(struct_size(imu, bvec, nr_pages), GFP_KERNEL); 1126 if (!imu) 1127 goto done; 1128 1129 ret = io_buffer_account_pin(ctx, pages, nr_pages, imu, last_hpage); 1130 if (ret) { 1131 unpin_user_pages(pages, nr_pages); 1132 goto done; 1133 } 1134 1135 off = (unsigned long) iov->iov_base & ~PAGE_MASK; 1136 size = iov->iov_len; 1137 /* store original address for later verification */ 1138 imu->ubuf = (unsigned long) iov->iov_base; 1139 imu->ubuf_end = imu->ubuf + iov->iov_len; 1140 imu->nr_bvecs = nr_pages; 1141 *pimu = imu; 1142 ret = 0; 1143 1144 if (folio) { 1145 bvec_set_page(&imu->bvec[0], pages[0], size, off); 1146 goto done; 1147 } 1148 for (i = 0; i < nr_pages; i++) { 1149 size_t vec_len; 1150 1151 vec_len = min_t(size_t, size, PAGE_SIZE - off); 1152 bvec_set_page(&imu->bvec[i], pages[i], vec_len, off); 1153 off = 0; 1154 size -= vec_len; 1155 } 1156 done: 1157 if (ret) 1158 kvfree(imu); 1159 kvfree(pages); 1160 return ret; 1161 } 1162 1163 static int io_buffers_map_alloc(struct io_ring_ctx *ctx, unsigned int nr_args) 1164 { 1165 ctx->user_bufs = kcalloc(nr_args, sizeof(*ctx->user_bufs), GFP_KERNEL); 1166 return ctx->user_bufs ? 0 : -ENOMEM; 1167 } 1168 1169 int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg, 1170 unsigned int nr_args, u64 __user *tags) 1171 { 1172 struct page *last_hpage = NULL; 1173 struct io_rsrc_data *data; 1174 int i, ret; 1175 struct iovec iov; 1176 1177 BUILD_BUG_ON(IORING_MAX_REG_BUFFERS >= (1u << 16)); 1178 1179 if (ctx->user_bufs) 1180 return -EBUSY; 1181 if (!nr_args || nr_args > IORING_MAX_REG_BUFFERS) 1182 return -EINVAL; 1183 ret = io_rsrc_data_alloc(ctx, IORING_RSRC_BUFFER, tags, nr_args, &data); 1184 if (ret) 1185 return ret; 1186 ret = io_buffers_map_alloc(ctx, nr_args); 1187 if (ret) { 1188 io_rsrc_data_free(data); 1189 return ret; 1190 } 1191 1192 for (i = 0; i < nr_args; i++, ctx->nr_user_bufs++) { 1193 if (arg) { 1194 ret = io_copy_iov(ctx, &iov, arg, i); 1195 if (ret) 1196 break; 1197 ret = io_buffer_validate(&iov); 1198 if (ret) 1199 break; 1200 } else { 1201 memset(&iov, 0, sizeof(iov)); 1202 } 1203 1204 if (!iov.iov_base && *io_get_tag_slot(data, i)) { 1205 ret = -EINVAL; 1206 break; 1207 } 1208 1209 ret = io_sqe_buffer_register(ctx, &iov, &ctx->user_bufs[i], 1210 &last_hpage); 1211 if (ret) 1212 break; 1213 } 1214 1215 WARN_ON_ONCE(ctx->buf_data); 1216 1217 ctx->buf_data = data; 1218 if (ret) 1219 __io_sqe_buffers_unregister(ctx); 1220 return ret; 1221 } 1222 1223 int io_import_fixed(int ddir, struct iov_iter *iter, 1224 struct io_mapped_ubuf *imu, 1225 u64 buf_addr, size_t len) 1226 { 1227 u64 buf_end; 1228 size_t offset; 1229 1230 if (WARN_ON_ONCE(!imu)) 1231 return -EFAULT; 1232 if (unlikely(check_add_overflow(buf_addr, (u64)len, &buf_end))) 1233 return -EFAULT; 1234 /* not inside the mapped region */ 1235 if (unlikely(buf_addr < imu->ubuf || buf_end > imu->ubuf_end)) 1236 return -EFAULT; 1237 1238 /* 1239 * Might not be a start of buffer, set size appropriately 1240 * and advance us to the beginning. 1241 */ 1242 offset = buf_addr - imu->ubuf; 1243 iov_iter_bvec(iter, ddir, imu->bvec, imu->nr_bvecs, offset + len); 1244 1245 if (offset) { 1246 /* 1247 * Don't use iov_iter_advance() here, as it's really slow for 1248 * using the latter parts of a big fixed buffer - it iterates 1249 * over each segment manually. We can cheat a bit here, because 1250 * we know that: 1251 * 1252 * 1) it's a BVEC iter, we set it up 1253 * 2) all bvecs are PAGE_SIZE in size, except potentially the 1254 * first and last bvec 1255 * 1256 * So just find our index, and adjust the iterator afterwards. 1257 * If the offset is within the first bvec (or the whole first 1258 * bvec, just use iov_iter_advance(). This makes it easier 1259 * since we can just skip the first segment, which may not 1260 * be PAGE_SIZE aligned. 1261 */ 1262 const struct bio_vec *bvec = imu->bvec; 1263 1264 if (offset <= bvec->bv_len) { 1265 /* 1266 * Note, huge pages buffers consists of one large 1267 * bvec entry and should always go this way. The other 1268 * branch doesn't expect non PAGE_SIZE'd chunks. 1269 */ 1270 iter->bvec = bvec; 1271 iter->nr_segs = bvec->bv_len; 1272 iter->count -= offset; 1273 iter->iov_offset = offset; 1274 } else { 1275 unsigned long seg_skip; 1276 1277 /* skip first vec */ 1278 offset -= bvec->bv_len; 1279 seg_skip = 1 + (offset >> PAGE_SHIFT); 1280 1281 iter->bvec = bvec + seg_skip; 1282 iter->nr_segs -= seg_skip; 1283 iter->count -= bvec->bv_len + offset; 1284 iter->iov_offset = offset & ~PAGE_MASK; 1285 } 1286 } 1287 1288 return 0; 1289 } 1290