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