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 "alloc_cache.h" 17 #include "openclose.h" 18 #include "rsrc.h" 19 #include "memmap.h" 20 21 struct io_rsrc_update { 22 struct file *file; 23 u64 arg; 24 u32 nr_args; 25 u32 offset; 26 }; 27 28 static void io_rsrc_buf_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc); 29 static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov, 30 struct io_mapped_ubuf **pimu, 31 struct page **last_hpage); 32 33 /* only define max */ 34 #define IORING_MAX_FIXED_FILES (1U << 20) 35 #define IORING_MAX_REG_BUFFERS (1U << 14) 36 37 static const struct io_mapped_ubuf dummy_ubuf = { 38 /* set invalid range, so io_import_fixed() fails meeting it */ 39 .ubuf = -1UL, 40 .ubuf_end = 0, 41 }; 42 43 int __io_account_mem(struct user_struct *user, unsigned long nr_pages) 44 { 45 unsigned long page_limit, cur_pages, new_pages; 46 47 if (!nr_pages) 48 return 0; 49 50 /* Don't allow more pages than we can safely lock */ 51 page_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; 52 53 cur_pages = atomic_long_read(&user->locked_vm); 54 do { 55 new_pages = cur_pages + nr_pages; 56 if (new_pages > page_limit) 57 return -ENOMEM; 58 } while (!atomic_long_try_cmpxchg(&user->locked_vm, 59 &cur_pages, new_pages)); 60 return 0; 61 } 62 63 static void io_unaccount_mem(struct io_ring_ctx *ctx, unsigned long nr_pages) 64 { 65 if (ctx->user) 66 __io_unaccount_mem(ctx->user, nr_pages); 67 68 if (ctx->mm_account) 69 atomic64_sub(nr_pages, &ctx->mm_account->pinned_vm); 70 } 71 72 static int io_account_mem(struct io_ring_ctx *ctx, unsigned long nr_pages) 73 { 74 int ret; 75 76 if (ctx->user) { 77 ret = __io_account_mem(ctx->user, nr_pages); 78 if (ret) 79 return ret; 80 } 81 82 if (ctx->mm_account) 83 atomic64_add(nr_pages, &ctx->mm_account->pinned_vm); 84 85 return 0; 86 } 87 88 static int io_copy_iov(struct io_ring_ctx *ctx, struct iovec *dst, 89 void __user *arg, unsigned index) 90 { 91 struct iovec __user *src; 92 93 #ifdef CONFIG_COMPAT 94 if (ctx->compat) { 95 struct compat_iovec __user *ciovs; 96 struct compat_iovec ciov; 97 98 ciovs = (struct compat_iovec __user *) arg; 99 if (copy_from_user(&ciov, &ciovs[index], sizeof(ciov))) 100 return -EFAULT; 101 102 dst->iov_base = u64_to_user_ptr((u64)ciov.iov_base); 103 dst->iov_len = ciov.iov_len; 104 return 0; 105 } 106 #endif 107 src = (struct iovec __user *) arg; 108 if (copy_from_user(dst, &src[index], sizeof(*dst))) 109 return -EFAULT; 110 return 0; 111 } 112 113 static int io_buffer_validate(struct iovec *iov) 114 { 115 unsigned long tmp, acct_len = iov->iov_len + (PAGE_SIZE - 1); 116 117 /* 118 * Don't impose further limits on the size and buffer 119 * constraints here, we'll -EINVAL later when IO is 120 * submitted if they are wrong. 121 */ 122 if (!iov->iov_base) 123 return iov->iov_len ? -EFAULT : 0; 124 if (!iov->iov_len) 125 return -EFAULT; 126 127 /* arbitrary limit, but we need something */ 128 if (iov->iov_len > SZ_1G) 129 return -EFAULT; 130 131 if (check_add_overflow((unsigned long)iov->iov_base, acct_len, &tmp)) 132 return -EOVERFLOW; 133 134 return 0; 135 } 136 137 static void io_buffer_unmap(struct io_ring_ctx *ctx, struct io_mapped_ubuf **slot) 138 { 139 struct io_mapped_ubuf *imu = *slot; 140 unsigned int i; 141 142 if (imu != &dummy_ubuf) { 143 for (i = 0; i < imu->nr_bvecs; i++) 144 unpin_user_page(imu->bvec[i].bv_page); 145 if (imu->acct_pages) 146 io_unaccount_mem(ctx, imu->acct_pages); 147 kvfree(imu); 148 } 149 *slot = NULL; 150 } 151 152 static void io_rsrc_put_work(struct io_rsrc_node *node) 153 { 154 struct io_rsrc_put *prsrc = &node->item; 155 156 if (prsrc->tag) 157 io_post_aux_cqe(node->ctx, prsrc->tag, 0, 0); 158 159 switch (node->type) { 160 case IORING_RSRC_FILE: 161 fput(prsrc->file); 162 break; 163 case IORING_RSRC_BUFFER: 164 io_rsrc_buf_put(node->ctx, prsrc); 165 break; 166 default: 167 WARN_ON_ONCE(1); 168 break; 169 } 170 } 171 172 void io_rsrc_node_destroy(struct io_ring_ctx *ctx, struct io_rsrc_node *node) 173 { 174 if (!io_alloc_cache_put(&ctx->rsrc_node_cache, node)) 175 kfree(node); 176 } 177 178 void io_rsrc_node_ref_zero(struct io_rsrc_node *node) 179 __must_hold(&node->ctx->uring_lock) 180 { 181 struct io_ring_ctx *ctx = node->ctx; 182 183 while (!list_empty(&ctx->rsrc_ref_list)) { 184 node = list_first_entry(&ctx->rsrc_ref_list, 185 struct io_rsrc_node, node); 186 /* recycle ref nodes in order */ 187 if (node->refs) 188 break; 189 list_del(&node->node); 190 191 if (likely(!node->empty)) 192 io_rsrc_put_work(node); 193 io_rsrc_node_destroy(ctx, node); 194 } 195 if (list_empty(&ctx->rsrc_ref_list) && unlikely(ctx->rsrc_quiesce)) 196 wake_up_all(&ctx->rsrc_quiesce_wq); 197 } 198 199 struct io_rsrc_node *io_rsrc_node_alloc(struct io_ring_ctx *ctx) 200 { 201 struct io_rsrc_node *ref_node; 202 203 ref_node = io_alloc_cache_get(&ctx->rsrc_node_cache); 204 if (!ref_node) { 205 ref_node = kzalloc(sizeof(*ref_node), GFP_KERNEL); 206 if (!ref_node) 207 return NULL; 208 } 209 210 ref_node->ctx = ctx; 211 ref_node->empty = 0; 212 ref_node->refs = 1; 213 return ref_node; 214 } 215 216 __cold static int io_rsrc_ref_quiesce(struct io_rsrc_data *data, 217 struct io_ring_ctx *ctx) 218 { 219 struct io_rsrc_node *backup; 220 DEFINE_WAIT(we); 221 int ret; 222 223 /* As We may drop ->uring_lock, other task may have started quiesce */ 224 if (data->quiesce) 225 return -ENXIO; 226 227 backup = io_rsrc_node_alloc(ctx); 228 if (!backup) 229 return -ENOMEM; 230 ctx->rsrc_node->empty = true; 231 ctx->rsrc_node->type = -1; 232 list_add_tail(&ctx->rsrc_node->node, &ctx->rsrc_ref_list); 233 io_put_rsrc_node(ctx, ctx->rsrc_node); 234 ctx->rsrc_node = backup; 235 236 if (list_empty(&ctx->rsrc_ref_list)) 237 return 0; 238 239 if (ctx->flags & IORING_SETUP_DEFER_TASKRUN) { 240 atomic_set(&ctx->cq_wait_nr, 1); 241 smp_mb(); 242 } 243 244 ctx->rsrc_quiesce++; 245 data->quiesce = true; 246 do { 247 prepare_to_wait(&ctx->rsrc_quiesce_wq, &we, TASK_INTERRUPTIBLE); 248 mutex_unlock(&ctx->uring_lock); 249 250 ret = io_run_task_work_sig(ctx); 251 if (ret < 0) { 252 __set_current_state(TASK_RUNNING); 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 static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov, 876 struct io_mapped_ubuf **pimu, 877 struct page **last_hpage) 878 { 879 struct io_mapped_ubuf *imu = NULL; 880 struct page **pages = NULL; 881 unsigned long off; 882 size_t size; 883 int ret, nr_pages, i; 884 struct folio *folio = NULL; 885 886 *pimu = (struct io_mapped_ubuf *)&dummy_ubuf; 887 if (!iov->iov_base) 888 return 0; 889 890 ret = -ENOMEM; 891 pages = io_pin_pages((unsigned long) iov->iov_base, iov->iov_len, 892 &nr_pages); 893 if (IS_ERR(pages)) { 894 ret = PTR_ERR(pages); 895 pages = NULL; 896 goto done; 897 } 898 899 /* If it's a huge page, try to coalesce them into a single bvec entry */ 900 if (nr_pages > 1) { 901 folio = page_folio(pages[0]); 902 for (i = 1; i < nr_pages; i++) { 903 /* 904 * Pages must be consecutive and on the same folio for 905 * this to work 906 */ 907 if (page_folio(pages[i]) != folio || 908 pages[i] != pages[i - 1] + 1) { 909 folio = NULL; 910 break; 911 } 912 } 913 if (folio) { 914 /* 915 * The pages are bound to the folio, it doesn't 916 * actually unpin them but drops all but one reference, 917 * which is usually put down by io_buffer_unmap(). 918 * Note, needs a better helper. 919 */ 920 unpin_user_pages(&pages[1], nr_pages - 1); 921 nr_pages = 1; 922 } 923 } 924 925 imu = kvmalloc(struct_size(imu, bvec, nr_pages), GFP_KERNEL); 926 if (!imu) 927 goto done; 928 929 ret = io_buffer_account_pin(ctx, pages, nr_pages, imu, last_hpage); 930 if (ret) { 931 unpin_user_pages(pages, nr_pages); 932 goto done; 933 } 934 935 off = (unsigned long) iov->iov_base & ~PAGE_MASK; 936 size = iov->iov_len; 937 /* store original address for later verification */ 938 imu->ubuf = (unsigned long) iov->iov_base; 939 imu->ubuf_end = imu->ubuf + iov->iov_len; 940 imu->nr_bvecs = nr_pages; 941 *pimu = imu; 942 ret = 0; 943 944 if (folio) { 945 bvec_set_page(&imu->bvec[0], pages[0], size, off); 946 goto done; 947 } 948 for (i = 0; i < nr_pages; i++) { 949 size_t vec_len; 950 951 vec_len = min_t(size_t, size, PAGE_SIZE - off); 952 bvec_set_page(&imu->bvec[i], pages[i], vec_len, off); 953 off = 0; 954 size -= vec_len; 955 } 956 done: 957 if (ret) 958 kvfree(imu); 959 kvfree(pages); 960 return ret; 961 } 962 963 static int io_buffers_map_alloc(struct io_ring_ctx *ctx, unsigned int nr_args) 964 { 965 ctx->user_bufs = kcalloc(nr_args, sizeof(*ctx->user_bufs), GFP_KERNEL); 966 return ctx->user_bufs ? 0 : -ENOMEM; 967 } 968 969 int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg, 970 unsigned int nr_args, u64 __user *tags) 971 { 972 struct page *last_hpage = NULL; 973 struct io_rsrc_data *data; 974 int i, ret; 975 struct iovec iov; 976 977 BUILD_BUG_ON(IORING_MAX_REG_BUFFERS >= (1u << 16)); 978 979 if (ctx->user_bufs) 980 return -EBUSY; 981 if (!nr_args || nr_args > IORING_MAX_REG_BUFFERS) 982 return -EINVAL; 983 ret = io_rsrc_data_alloc(ctx, IORING_RSRC_BUFFER, tags, nr_args, &data); 984 if (ret) 985 return ret; 986 ret = io_buffers_map_alloc(ctx, nr_args); 987 if (ret) { 988 io_rsrc_data_free(data); 989 return ret; 990 } 991 992 for (i = 0; i < nr_args; i++, ctx->nr_user_bufs++) { 993 if (arg) { 994 ret = io_copy_iov(ctx, &iov, arg, i); 995 if (ret) 996 break; 997 ret = io_buffer_validate(&iov); 998 if (ret) 999 break; 1000 } else { 1001 memset(&iov, 0, sizeof(iov)); 1002 } 1003 1004 if (!iov.iov_base && *io_get_tag_slot(data, i)) { 1005 ret = -EINVAL; 1006 break; 1007 } 1008 1009 ret = io_sqe_buffer_register(ctx, &iov, &ctx->user_bufs[i], 1010 &last_hpage); 1011 if (ret) 1012 break; 1013 } 1014 1015 WARN_ON_ONCE(ctx->buf_data); 1016 1017 ctx->buf_data = data; 1018 if (ret) 1019 __io_sqe_buffers_unregister(ctx); 1020 return ret; 1021 } 1022 1023 int io_import_fixed(int ddir, struct iov_iter *iter, 1024 struct io_mapped_ubuf *imu, 1025 u64 buf_addr, size_t len) 1026 { 1027 u64 buf_end; 1028 size_t offset; 1029 1030 if (WARN_ON_ONCE(!imu)) 1031 return -EFAULT; 1032 if (unlikely(check_add_overflow(buf_addr, (u64)len, &buf_end))) 1033 return -EFAULT; 1034 /* not inside the mapped region */ 1035 if (unlikely(buf_addr < imu->ubuf || buf_end > imu->ubuf_end)) 1036 return -EFAULT; 1037 1038 /* 1039 * Might not be a start of buffer, set size appropriately 1040 * and advance us to the beginning. 1041 */ 1042 offset = buf_addr - imu->ubuf; 1043 iov_iter_bvec(iter, ddir, imu->bvec, imu->nr_bvecs, offset + len); 1044 1045 if (offset) { 1046 /* 1047 * Don't use iov_iter_advance() here, as it's really slow for 1048 * using the latter parts of a big fixed buffer - it iterates 1049 * over each segment manually. We can cheat a bit here, because 1050 * we know that: 1051 * 1052 * 1) it's a BVEC iter, we set it up 1053 * 2) all bvecs are PAGE_SIZE in size, except potentially the 1054 * first and last bvec 1055 * 1056 * So just find our index, and adjust the iterator afterwards. 1057 * If the offset is within the first bvec (or the whole first 1058 * bvec, just use iov_iter_advance(). This makes it easier 1059 * since we can just skip the first segment, which may not 1060 * be PAGE_SIZE aligned. 1061 */ 1062 const struct bio_vec *bvec = imu->bvec; 1063 1064 if (offset < bvec->bv_len) { 1065 /* 1066 * Note, huge pages buffers consists of one large 1067 * bvec entry and should always go this way. The other 1068 * branch doesn't expect non PAGE_SIZE'd chunks. 1069 */ 1070 iter->bvec = bvec; 1071 iter->nr_segs = bvec->bv_len; 1072 iter->count -= offset; 1073 iter->iov_offset = offset; 1074 } else { 1075 unsigned long seg_skip; 1076 1077 /* skip first vec */ 1078 offset -= bvec->bv_len; 1079 seg_skip = 1 + (offset >> PAGE_SHIFT); 1080 1081 iter->bvec = bvec + seg_skip; 1082 iter->nr_segs -= seg_skip; 1083 iter->count -= bvec->bv_len + offset; 1084 iter->iov_offset = offset & ~PAGE_MASK; 1085 } 1086 } 1087 1088 return 0; 1089 } 1090