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 int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov, 27 struct io_mapped_ubuf **pimu, 28 struct page **last_hpage); 29 30 /* only define max */ 31 #define IORING_MAX_FIXED_FILES (1U << 20) 32 #define IORING_MAX_REG_BUFFERS (1U << 14) 33 34 static inline bool io_put_rsrc_data_ref(struct io_rsrc_data *rsrc_data) 35 { 36 return !--rsrc_data->refs; 37 } 38 39 int __io_account_mem(struct user_struct *user, unsigned long nr_pages) 40 { 41 unsigned long page_limit, cur_pages, new_pages; 42 43 if (!nr_pages) 44 return 0; 45 46 /* Don't allow more pages than we can safely lock */ 47 page_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; 48 49 cur_pages = atomic_long_read(&user->locked_vm); 50 do { 51 new_pages = cur_pages + nr_pages; 52 if (new_pages > page_limit) 53 return -ENOMEM; 54 } while (!atomic_long_try_cmpxchg(&user->locked_vm, 55 &cur_pages, new_pages)); 56 return 0; 57 } 58 59 static void io_unaccount_mem(struct io_ring_ctx *ctx, unsigned long nr_pages) 60 { 61 if (ctx->user) 62 __io_unaccount_mem(ctx->user, nr_pages); 63 64 if (ctx->mm_account) 65 atomic64_sub(nr_pages, &ctx->mm_account->pinned_vm); 66 } 67 68 static int io_account_mem(struct io_ring_ctx *ctx, unsigned long nr_pages) 69 { 70 int ret; 71 72 if (ctx->user) { 73 ret = __io_account_mem(ctx->user, nr_pages); 74 if (ret) 75 return ret; 76 } 77 78 if (ctx->mm_account) 79 atomic64_add(nr_pages, &ctx->mm_account->pinned_vm); 80 81 return 0; 82 } 83 84 static int io_copy_iov(struct io_ring_ctx *ctx, struct iovec *dst, 85 void __user *arg, unsigned index) 86 { 87 struct iovec __user *src; 88 89 #ifdef CONFIG_COMPAT 90 if (ctx->compat) { 91 struct compat_iovec __user *ciovs; 92 struct compat_iovec ciov; 93 94 ciovs = (struct compat_iovec __user *) arg; 95 if (copy_from_user(&ciov, &ciovs[index], sizeof(ciov))) 96 return -EFAULT; 97 98 dst->iov_base = u64_to_user_ptr((u64)ciov.iov_base); 99 dst->iov_len = ciov.iov_len; 100 return 0; 101 } 102 #endif 103 src = (struct iovec __user *) arg; 104 if (copy_from_user(dst, &src[index], sizeof(*dst))) 105 return -EFAULT; 106 return 0; 107 } 108 109 static int io_buffer_validate(struct iovec *iov) 110 { 111 unsigned long tmp, acct_len = iov->iov_len + (PAGE_SIZE - 1); 112 113 /* 114 * Don't impose further limits on the size and buffer 115 * constraints here, we'll -EINVAL later when IO is 116 * submitted if they are wrong. 117 */ 118 if (!iov->iov_base) 119 return iov->iov_len ? -EFAULT : 0; 120 if (!iov->iov_len) 121 return -EFAULT; 122 123 /* arbitrary limit, but we need something */ 124 if (iov->iov_len > SZ_1G) 125 return -EFAULT; 126 127 if (check_add_overflow((unsigned long)iov->iov_base, acct_len, &tmp)) 128 return -EOVERFLOW; 129 130 return 0; 131 } 132 133 static void io_buffer_unmap(struct io_ring_ctx *ctx, struct io_mapped_ubuf **slot) 134 { 135 struct io_mapped_ubuf *imu = *slot; 136 unsigned int i; 137 138 if (imu != ctx->dummy_ubuf) { 139 for (i = 0; i < imu->nr_bvecs; i++) 140 unpin_user_page(imu->bvec[i].bv_page); 141 if (imu->acct_pages) 142 io_unaccount_mem(ctx, imu->acct_pages); 143 kvfree(imu); 144 } 145 *slot = NULL; 146 } 147 148 static void io_rsrc_put_work_one(struct io_rsrc_data *rsrc_data, 149 struct io_rsrc_put *prsrc) 150 { 151 struct io_ring_ctx *ctx = rsrc_data->ctx; 152 153 if (prsrc->tag) 154 io_post_aux_cqe(ctx, prsrc->tag, 0, 0); 155 rsrc_data->do_put(ctx, prsrc); 156 } 157 158 static void __io_rsrc_put_work(struct io_rsrc_node *ref_node) 159 { 160 struct io_rsrc_data *rsrc_data = ref_node->rsrc_data; 161 struct io_rsrc_put *prsrc, *tmp; 162 163 if (ref_node->inline_items) 164 io_rsrc_put_work_one(rsrc_data, &ref_node->item); 165 166 list_for_each_entry_safe(prsrc, tmp, &ref_node->item_list, list) { 167 list_del(&prsrc->list); 168 io_rsrc_put_work_one(rsrc_data, prsrc); 169 kfree(prsrc); 170 } 171 172 io_rsrc_node_destroy(rsrc_data->ctx, ref_node); 173 if (io_put_rsrc_data_ref(rsrc_data)) 174 complete(&rsrc_data->done); 175 } 176 177 void io_wait_rsrc_data(struct io_rsrc_data *data) 178 { 179 if (data && !io_put_rsrc_data_ref(data)) 180 wait_for_completion(&data->done); 181 } 182 183 void io_rsrc_node_destroy(struct io_ring_ctx *ctx, struct io_rsrc_node *node) 184 { 185 if (!io_alloc_cache_put(&ctx->rsrc_node_cache, &node->cache)) 186 kfree(node); 187 } 188 189 void io_rsrc_node_ref_zero(struct io_rsrc_node *node) 190 __must_hold(&node->rsrc_data->ctx->uring_lock) 191 { 192 struct io_ring_ctx *ctx = node->rsrc_data->ctx; 193 194 while (!list_empty(&ctx->rsrc_ref_list)) { 195 node = list_first_entry(&ctx->rsrc_ref_list, 196 struct io_rsrc_node, node); 197 /* recycle ref nodes in order */ 198 if (node->refs) 199 break; 200 list_del(&node->node); 201 __io_rsrc_put_work(node); 202 } 203 } 204 205 struct io_rsrc_node *io_rsrc_node_alloc(struct io_ring_ctx *ctx) 206 { 207 struct io_rsrc_node *ref_node; 208 struct io_cache_entry *entry; 209 210 entry = io_alloc_cache_get(&ctx->rsrc_node_cache); 211 if (entry) { 212 ref_node = container_of(entry, struct io_rsrc_node, cache); 213 } else { 214 ref_node = kzalloc(sizeof(*ref_node), GFP_KERNEL); 215 if (!ref_node) 216 return NULL; 217 } 218 219 ref_node->rsrc_data = NULL; 220 ref_node->refs = 1; 221 INIT_LIST_HEAD(&ref_node->node); 222 INIT_LIST_HEAD(&ref_node->item_list); 223 ref_node->inline_items = 0; 224 return ref_node; 225 } 226 227 void io_rsrc_node_switch(struct io_ring_ctx *ctx, 228 struct io_rsrc_data *data_to_kill) 229 __must_hold(&ctx->uring_lock) 230 { 231 struct io_rsrc_node *node = ctx->rsrc_node; 232 struct io_rsrc_node *backup = io_rsrc_node_alloc(ctx); 233 234 if (WARN_ON_ONCE(!backup)) 235 return; 236 237 data_to_kill->refs++; 238 node->rsrc_data = data_to_kill; 239 list_add_tail(&node->node, &ctx->rsrc_ref_list); 240 /* put master ref */ 241 io_put_rsrc_node(ctx, node); 242 ctx->rsrc_node = backup; 243 } 244 245 int io_rsrc_node_switch_start(struct io_ring_ctx *ctx) 246 { 247 if (io_alloc_cache_empty(&ctx->rsrc_node_cache)) { 248 struct io_rsrc_node *node = kzalloc(sizeof(*node), GFP_KERNEL); 249 250 if (!node) 251 return -ENOMEM; 252 io_alloc_cache_put(&ctx->rsrc_node_cache, &node->cache); 253 } 254 return 0; 255 } 256 257 __cold static int io_rsrc_ref_quiesce(struct io_rsrc_data *data, 258 struct io_ring_ctx *ctx) 259 { 260 int ret; 261 262 /* As we may drop ->uring_lock, other task may have started quiesce */ 263 if (data->quiesce) 264 return -ENXIO; 265 ret = io_rsrc_node_switch_start(ctx); 266 if (ret) 267 return ret; 268 io_rsrc_node_switch(ctx, data); 269 270 /* kill initial ref */ 271 if (io_put_rsrc_data_ref(data)) 272 return 0; 273 274 data->quiesce = true; 275 do { 276 mutex_unlock(&ctx->uring_lock); 277 ret = io_run_task_work_sig(ctx); 278 if (ret < 0) { 279 mutex_lock(&ctx->uring_lock); 280 if (!data->refs) { 281 ret = 0; 282 } else { 283 /* restore the master reference */ 284 data->refs++; 285 } 286 break; 287 } 288 wait_for_completion_interruptible(&data->done); 289 mutex_lock(&ctx->uring_lock); 290 ret = 0; 291 } while (data->refs); 292 data->quiesce = false; 293 294 return ret; 295 } 296 297 static void io_free_page_table(void **table, size_t size) 298 { 299 unsigned i, nr_tables = DIV_ROUND_UP(size, PAGE_SIZE); 300 301 for (i = 0; i < nr_tables; i++) 302 kfree(table[i]); 303 kfree(table); 304 } 305 306 static void io_rsrc_data_free(struct io_rsrc_data *data) 307 { 308 size_t size = data->nr * sizeof(data->tags[0][0]); 309 310 if (data->tags) 311 io_free_page_table((void **)data->tags, size); 312 kfree(data); 313 } 314 315 static __cold void **io_alloc_page_table(size_t size) 316 { 317 unsigned i, nr_tables = DIV_ROUND_UP(size, PAGE_SIZE); 318 size_t init_size = size; 319 void **table; 320 321 table = kcalloc(nr_tables, sizeof(*table), GFP_KERNEL_ACCOUNT); 322 if (!table) 323 return NULL; 324 325 for (i = 0; i < nr_tables; i++) { 326 unsigned int this_size = min_t(size_t, size, PAGE_SIZE); 327 328 table[i] = kzalloc(this_size, GFP_KERNEL_ACCOUNT); 329 if (!table[i]) { 330 io_free_page_table(table, init_size); 331 return NULL; 332 } 333 size -= this_size; 334 } 335 return table; 336 } 337 338 __cold static int io_rsrc_data_alloc(struct io_ring_ctx *ctx, 339 rsrc_put_fn *do_put, u64 __user *utags, 340 unsigned nr, struct io_rsrc_data **pdata) 341 { 342 struct io_rsrc_data *data; 343 int ret = 0; 344 unsigned i; 345 346 data = kzalloc(sizeof(*data), GFP_KERNEL); 347 if (!data) 348 return -ENOMEM; 349 data->tags = (u64 **)io_alloc_page_table(nr * sizeof(data->tags[0][0])); 350 if (!data->tags) { 351 kfree(data); 352 return -ENOMEM; 353 } 354 355 data->nr = nr; 356 data->ctx = ctx; 357 data->do_put = do_put; 358 data->refs = 1; 359 if (utags) { 360 ret = -EFAULT; 361 for (i = 0; i < nr; i++) { 362 u64 *tag_slot = io_get_tag_slot(data, i); 363 364 if (copy_from_user(tag_slot, &utags[i], 365 sizeof(*tag_slot))) 366 goto fail; 367 } 368 } 369 init_completion(&data->done); 370 *pdata = data; 371 return 0; 372 fail: 373 io_rsrc_data_free(data); 374 return ret; 375 } 376 377 static int __io_sqe_files_update(struct io_ring_ctx *ctx, 378 struct io_uring_rsrc_update2 *up, 379 unsigned nr_args) 380 { 381 u64 __user *tags = u64_to_user_ptr(up->tags); 382 __s32 __user *fds = u64_to_user_ptr(up->data); 383 struct io_rsrc_data *data = ctx->file_data; 384 struct io_fixed_file *file_slot; 385 struct file *file; 386 int fd, i, err = 0; 387 unsigned int done; 388 bool needs_switch = false; 389 390 if (!ctx->file_data) 391 return -ENXIO; 392 if (up->offset + nr_args > ctx->nr_user_files) 393 return -EINVAL; 394 395 for (done = 0; done < nr_args; done++) { 396 u64 tag = 0; 397 398 if ((tags && copy_from_user(&tag, &tags[done], sizeof(tag))) || 399 copy_from_user(&fd, &fds[done], sizeof(fd))) { 400 err = -EFAULT; 401 break; 402 } 403 if ((fd == IORING_REGISTER_FILES_SKIP || fd == -1) && tag) { 404 err = -EINVAL; 405 break; 406 } 407 if (fd == IORING_REGISTER_FILES_SKIP) 408 continue; 409 410 i = array_index_nospec(up->offset + done, ctx->nr_user_files); 411 file_slot = io_fixed_file_slot(&ctx->file_table, i); 412 413 if (file_slot->file_ptr) { 414 file = (struct file *)(file_slot->file_ptr & FFS_MASK); 415 err = io_queue_rsrc_removal(data, i, ctx->rsrc_node, file); 416 if (err) 417 break; 418 file_slot->file_ptr = 0; 419 io_file_bitmap_clear(&ctx->file_table, i); 420 needs_switch = true; 421 } 422 if (fd != -1) { 423 file = fget(fd); 424 if (!file) { 425 err = -EBADF; 426 break; 427 } 428 /* 429 * Don't allow io_uring instances to be registered. If 430 * UNIX isn't enabled, then this causes a reference 431 * cycle and this instance can never get freed. If UNIX 432 * is enabled we'll handle it just fine, but there's 433 * still no point in allowing a ring fd as it doesn't 434 * support regular read/write anyway. 435 */ 436 if (io_is_uring_fops(file)) { 437 fput(file); 438 err = -EBADF; 439 break; 440 } 441 err = io_scm_file_account(ctx, file); 442 if (err) { 443 fput(file); 444 break; 445 } 446 *io_get_tag_slot(data, i) = tag; 447 io_fixed_file_set(file_slot, file); 448 io_file_bitmap_set(&ctx->file_table, i); 449 } 450 } 451 452 if (needs_switch) 453 io_rsrc_node_switch(ctx, data); 454 return done ? done : err; 455 } 456 457 static int __io_sqe_buffers_update(struct io_ring_ctx *ctx, 458 struct io_uring_rsrc_update2 *up, 459 unsigned int nr_args) 460 { 461 u64 __user *tags = u64_to_user_ptr(up->tags); 462 struct iovec iov, __user *iovs = u64_to_user_ptr(up->data); 463 struct page *last_hpage = NULL; 464 bool needs_switch = false; 465 __u32 done; 466 int i, err; 467 468 if (!ctx->buf_data) 469 return -ENXIO; 470 if (up->offset + nr_args > ctx->nr_user_bufs) 471 return -EINVAL; 472 473 for (done = 0; done < nr_args; done++) { 474 struct io_mapped_ubuf *imu; 475 int offset = up->offset + done; 476 u64 tag = 0; 477 478 err = io_copy_iov(ctx, &iov, iovs, done); 479 if (err) 480 break; 481 if (tags && copy_from_user(&tag, &tags[done], sizeof(tag))) { 482 err = -EFAULT; 483 break; 484 } 485 err = io_buffer_validate(&iov); 486 if (err) 487 break; 488 if (!iov.iov_base && tag) { 489 err = -EINVAL; 490 break; 491 } 492 err = io_sqe_buffer_register(ctx, &iov, &imu, &last_hpage); 493 if (err) 494 break; 495 496 i = array_index_nospec(offset, ctx->nr_user_bufs); 497 if (ctx->user_bufs[i] != ctx->dummy_ubuf) { 498 err = io_queue_rsrc_removal(ctx->buf_data, i, 499 ctx->rsrc_node, ctx->user_bufs[i]); 500 if (unlikely(err)) { 501 io_buffer_unmap(ctx, &imu); 502 break; 503 } 504 ctx->user_bufs[i] = ctx->dummy_ubuf; 505 needs_switch = true; 506 } 507 508 ctx->user_bufs[i] = imu; 509 *io_get_tag_slot(ctx->buf_data, i) = tag; 510 } 511 512 if (needs_switch) 513 io_rsrc_node_switch(ctx, ctx->buf_data); 514 return done ? done : err; 515 } 516 517 static int __io_register_rsrc_update(struct io_ring_ctx *ctx, unsigned type, 518 struct io_uring_rsrc_update2 *up, 519 unsigned nr_args) 520 { 521 __u32 tmp; 522 int err; 523 524 lockdep_assert_held(&ctx->uring_lock); 525 526 if (check_add_overflow(up->offset, nr_args, &tmp)) 527 return -EOVERFLOW; 528 err = io_rsrc_node_switch_start(ctx); 529 if (err) 530 return err; 531 532 switch (type) { 533 case IORING_RSRC_FILE: 534 return __io_sqe_files_update(ctx, up, nr_args); 535 case IORING_RSRC_BUFFER: 536 return __io_sqe_buffers_update(ctx, up, nr_args); 537 } 538 return -EINVAL; 539 } 540 541 int io_register_files_update(struct io_ring_ctx *ctx, void __user *arg, 542 unsigned nr_args) 543 { 544 struct io_uring_rsrc_update2 up; 545 546 if (!nr_args) 547 return -EINVAL; 548 memset(&up, 0, sizeof(up)); 549 if (copy_from_user(&up, arg, sizeof(struct io_uring_rsrc_update))) 550 return -EFAULT; 551 if (up.resv || up.resv2) 552 return -EINVAL; 553 return __io_register_rsrc_update(ctx, IORING_RSRC_FILE, &up, nr_args); 554 } 555 556 int io_register_rsrc_update(struct io_ring_ctx *ctx, void __user *arg, 557 unsigned size, unsigned type) 558 { 559 struct io_uring_rsrc_update2 up; 560 561 if (size != sizeof(up)) 562 return -EINVAL; 563 if (copy_from_user(&up, arg, sizeof(up))) 564 return -EFAULT; 565 if (!up.nr || up.resv || up.resv2) 566 return -EINVAL; 567 return __io_register_rsrc_update(ctx, type, &up, up.nr); 568 } 569 570 __cold int io_register_rsrc(struct io_ring_ctx *ctx, void __user *arg, 571 unsigned int size, unsigned int type) 572 { 573 struct io_uring_rsrc_register rr; 574 575 /* keep it extendible */ 576 if (size != sizeof(rr)) 577 return -EINVAL; 578 579 memset(&rr, 0, sizeof(rr)); 580 if (copy_from_user(&rr, arg, size)) 581 return -EFAULT; 582 if (!rr.nr || rr.resv2) 583 return -EINVAL; 584 if (rr.flags & ~IORING_RSRC_REGISTER_SPARSE) 585 return -EINVAL; 586 587 switch (type) { 588 case IORING_RSRC_FILE: 589 if (rr.flags & IORING_RSRC_REGISTER_SPARSE && rr.data) 590 break; 591 return io_sqe_files_register(ctx, u64_to_user_ptr(rr.data), 592 rr.nr, u64_to_user_ptr(rr.tags)); 593 case IORING_RSRC_BUFFER: 594 if (rr.flags & IORING_RSRC_REGISTER_SPARSE && rr.data) 595 break; 596 return io_sqe_buffers_register(ctx, u64_to_user_ptr(rr.data), 597 rr.nr, u64_to_user_ptr(rr.tags)); 598 } 599 return -EINVAL; 600 } 601 602 int io_files_update_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) 603 { 604 struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update); 605 606 if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT))) 607 return -EINVAL; 608 if (sqe->rw_flags || sqe->splice_fd_in) 609 return -EINVAL; 610 611 up->offset = READ_ONCE(sqe->off); 612 up->nr_args = READ_ONCE(sqe->len); 613 if (!up->nr_args) 614 return -EINVAL; 615 up->arg = READ_ONCE(sqe->addr); 616 return 0; 617 } 618 619 static int io_files_update_with_index_alloc(struct io_kiocb *req, 620 unsigned int issue_flags) 621 { 622 struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update); 623 __s32 __user *fds = u64_to_user_ptr(up->arg); 624 unsigned int done; 625 struct file *file; 626 int ret, fd; 627 628 if (!req->ctx->file_data) 629 return -ENXIO; 630 631 for (done = 0; done < up->nr_args; done++) { 632 if (copy_from_user(&fd, &fds[done], sizeof(fd))) { 633 ret = -EFAULT; 634 break; 635 } 636 637 file = fget(fd); 638 if (!file) { 639 ret = -EBADF; 640 break; 641 } 642 ret = io_fixed_fd_install(req, issue_flags, file, 643 IORING_FILE_INDEX_ALLOC); 644 if (ret < 0) 645 break; 646 if (copy_to_user(&fds[done], &ret, sizeof(ret))) { 647 __io_close_fixed(req->ctx, issue_flags, ret); 648 ret = -EFAULT; 649 break; 650 } 651 } 652 653 if (done) 654 return done; 655 return ret; 656 } 657 658 int io_files_update(struct io_kiocb *req, unsigned int issue_flags) 659 { 660 struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update); 661 struct io_ring_ctx *ctx = req->ctx; 662 struct io_uring_rsrc_update2 up2; 663 int ret; 664 665 up2.offset = up->offset; 666 up2.data = up->arg; 667 up2.nr = 0; 668 up2.tags = 0; 669 up2.resv = 0; 670 up2.resv2 = 0; 671 672 if (up->offset == IORING_FILE_INDEX_ALLOC) { 673 ret = io_files_update_with_index_alloc(req, issue_flags); 674 } else { 675 io_ring_submit_lock(ctx, issue_flags); 676 ret = __io_register_rsrc_update(ctx, IORING_RSRC_FILE, 677 &up2, up->nr_args); 678 io_ring_submit_unlock(ctx, issue_flags); 679 } 680 681 if (ret < 0) 682 req_set_fail(req); 683 io_req_set_res(req, ret, 0); 684 return IOU_OK; 685 } 686 687 int io_queue_rsrc_removal(struct io_rsrc_data *data, unsigned idx, 688 struct io_rsrc_node *node, void *rsrc) 689 { 690 u64 *tag_slot = io_get_tag_slot(data, idx); 691 struct io_rsrc_put *prsrc; 692 bool inline_item = true; 693 694 if (!node->inline_items) { 695 prsrc = &node->item; 696 node->inline_items++; 697 } else { 698 prsrc = kzalloc(sizeof(*prsrc), GFP_KERNEL); 699 if (!prsrc) 700 return -ENOMEM; 701 inline_item = false; 702 } 703 704 prsrc->tag = *tag_slot; 705 *tag_slot = 0; 706 prsrc->rsrc = rsrc; 707 if (!inline_item) 708 list_add(&prsrc->list, &node->item_list); 709 return 0; 710 } 711 712 void __io_sqe_files_unregister(struct io_ring_ctx *ctx) 713 { 714 int i; 715 716 for (i = 0; i < ctx->nr_user_files; i++) { 717 struct file *file = io_file_from_index(&ctx->file_table, i); 718 719 /* skip scm accounted files, they'll be freed by ->ring_sock */ 720 if (!file || io_file_need_scm(file)) 721 continue; 722 io_file_bitmap_clear(&ctx->file_table, i); 723 fput(file); 724 } 725 726 #if defined(CONFIG_UNIX) 727 if (ctx->ring_sock) { 728 struct sock *sock = ctx->ring_sock->sk; 729 struct sk_buff *skb; 730 731 while ((skb = skb_dequeue(&sock->sk_receive_queue)) != NULL) 732 kfree_skb(skb); 733 } 734 #endif 735 io_free_file_tables(&ctx->file_table); 736 io_file_table_set_alloc_range(ctx, 0, 0); 737 io_rsrc_data_free(ctx->file_data); 738 ctx->file_data = NULL; 739 ctx->nr_user_files = 0; 740 } 741 742 int io_sqe_files_unregister(struct io_ring_ctx *ctx) 743 { 744 unsigned nr = ctx->nr_user_files; 745 int ret; 746 747 if (!ctx->file_data) 748 return -ENXIO; 749 750 /* 751 * Quiesce may unlock ->uring_lock, and while it's not held 752 * prevent new requests using the table. 753 */ 754 ctx->nr_user_files = 0; 755 ret = io_rsrc_ref_quiesce(ctx->file_data, ctx); 756 ctx->nr_user_files = nr; 757 if (!ret) 758 __io_sqe_files_unregister(ctx); 759 return ret; 760 } 761 762 /* 763 * Ensure the UNIX gc is aware of our file set, so we are certain that 764 * the io_uring can be safely unregistered on process exit, even if we have 765 * loops in the file referencing. We account only files that can hold other 766 * files because otherwise they can't form a loop and so are not interesting 767 * for GC. 768 */ 769 int __io_scm_file_account(struct io_ring_ctx *ctx, struct file *file) 770 { 771 #if defined(CONFIG_UNIX) 772 struct sock *sk = ctx->ring_sock->sk; 773 struct sk_buff_head *head = &sk->sk_receive_queue; 774 struct scm_fp_list *fpl; 775 struct sk_buff *skb; 776 777 if (likely(!io_file_need_scm(file))) 778 return 0; 779 780 /* 781 * See if we can merge this file into an existing skb SCM_RIGHTS 782 * file set. If there's no room, fall back to allocating a new skb 783 * and filling it in. 784 */ 785 spin_lock_irq(&head->lock); 786 skb = skb_peek(head); 787 if (skb && UNIXCB(skb).fp->count < SCM_MAX_FD) 788 __skb_unlink(skb, head); 789 else 790 skb = NULL; 791 spin_unlock_irq(&head->lock); 792 793 if (!skb) { 794 fpl = kzalloc(sizeof(*fpl), GFP_KERNEL); 795 if (!fpl) 796 return -ENOMEM; 797 798 skb = alloc_skb(0, GFP_KERNEL); 799 if (!skb) { 800 kfree(fpl); 801 return -ENOMEM; 802 } 803 804 fpl->user = get_uid(current_user()); 805 fpl->max = SCM_MAX_FD; 806 fpl->count = 0; 807 808 UNIXCB(skb).fp = fpl; 809 skb->sk = sk; 810 skb->scm_io_uring = 1; 811 skb->destructor = unix_destruct_scm; 812 refcount_add(skb->truesize, &sk->sk_wmem_alloc); 813 } 814 815 fpl = UNIXCB(skb).fp; 816 fpl->fp[fpl->count++] = get_file(file); 817 unix_inflight(fpl->user, file); 818 skb_queue_head(head, skb); 819 fput(file); 820 #endif 821 return 0; 822 } 823 824 static __cold void io_rsrc_file_scm_put(struct io_ring_ctx *ctx, struct file *file) 825 { 826 #if defined(CONFIG_UNIX) 827 struct sock *sock = ctx->ring_sock->sk; 828 struct sk_buff_head list, *head = &sock->sk_receive_queue; 829 struct sk_buff *skb; 830 int i; 831 832 __skb_queue_head_init(&list); 833 834 /* 835 * Find the skb that holds this file in its SCM_RIGHTS. When found, 836 * remove this entry and rearrange the file array. 837 */ 838 skb = skb_dequeue(head); 839 while (skb) { 840 struct scm_fp_list *fp; 841 842 fp = UNIXCB(skb).fp; 843 for (i = 0; i < fp->count; i++) { 844 int left; 845 846 if (fp->fp[i] != file) 847 continue; 848 849 unix_notinflight(fp->user, fp->fp[i]); 850 left = fp->count - 1 - i; 851 if (left) { 852 memmove(&fp->fp[i], &fp->fp[i + 1], 853 left * sizeof(struct file *)); 854 } 855 fp->count--; 856 if (!fp->count) { 857 kfree_skb(skb); 858 skb = NULL; 859 } else { 860 __skb_queue_tail(&list, skb); 861 } 862 fput(file); 863 file = NULL; 864 break; 865 } 866 867 if (!file) 868 break; 869 870 __skb_queue_tail(&list, skb); 871 872 skb = skb_dequeue(head); 873 } 874 875 if (skb_peek(&list)) { 876 spin_lock_irq(&head->lock); 877 while ((skb = __skb_dequeue(&list)) != NULL) 878 __skb_queue_tail(head, skb); 879 spin_unlock_irq(&head->lock); 880 } 881 #endif 882 } 883 884 static void io_rsrc_file_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc) 885 { 886 struct file *file = prsrc->file; 887 888 if (likely(!io_file_need_scm(file))) 889 fput(file); 890 else 891 io_rsrc_file_scm_put(ctx, file); 892 } 893 894 int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg, 895 unsigned nr_args, u64 __user *tags) 896 { 897 __s32 __user *fds = (__s32 __user *) arg; 898 struct file *file; 899 int fd, ret; 900 unsigned i; 901 902 if (ctx->file_data) 903 return -EBUSY; 904 if (!nr_args) 905 return -EINVAL; 906 if (nr_args > IORING_MAX_FIXED_FILES) 907 return -EMFILE; 908 if (nr_args > rlimit(RLIMIT_NOFILE)) 909 return -EMFILE; 910 ret = io_rsrc_data_alloc(ctx, io_rsrc_file_put, tags, nr_args, 911 &ctx->file_data); 912 if (ret) 913 return ret; 914 915 if (!io_alloc_file_tables(&ctx->file_table, nr_args)) { 916 io_rsrc_data_free(ctx->file_data); 917 ctx->file_data = NULL; 918 return -ENOMEM; 919 } 920 921 for (i = 0; i < nr_args; i++, ctx->nr_user_files++) { 922 struct io_fixed_file *file_slot; 923 924 if (fds && copy_from_user(&fd, &fds[i], sizeof(fd))) { 925 ret = -EFAULT; 926 goto fail; 927 } 928 /* allow sparse sets */ 929 if (!fds || fd == -1) { 930 ret = -EINVAL; 931 if (unlikely(*io_get_tag_slot(ctx->file_data, i))) 932 goto fail; 933 continue; 934 } 935 936 file = fget(fd); 937 ret = -EBADF; 938 if (unlikely(!file)) 939 goto fail; 940 941 /* 942 * Don't allow io_uring instances to be registered. If UNIX 943 * isn't enabled, then this causes a reference cycle and this 944 * instance can never get freed. If UNIX is enabled we'll 945 * handle it just fine, but there's still no point in allowing 946 * a ring fd as it doesn't support regular read/write anyway. 947 */ 948 if (io_is_uring_fops(file)) { 949 fput(file); 950 goto fail; 951 } 952 ret = io_scm_file_account(ctx, file); 953 if (ret) { 954 fput(file); 955 goto fail; 956 } 957 file_slot = io_fixed_file_slot(&ctx->file_table, i); 958 io_fixed_file_set(file_slot, file); 959 io_file_bitmap_set(&ctx->file_table, i); 960 } 961 962 /* default it to the whole table */ 963 io_file_table_set_alloc_range(ctx, 0, ctx->nr_user_files); 964 return 0; 965 fail: 966 __io_sqe_files_unregister(ctx); 967 return ret; 968 } 969 970 static void io_rsrc_buf_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc) 971 { 972 io_buffer_unmap(ctx, &prsrc->buf); 973 prsrc->buf = NULL; 974 } 975 976 void __io_sqe_buffers_unregister(struct io_ring_ctx *ctx) 977 { 978 unsigned int i; 979 980 for (i = 0; i < ctx->nr_user_bufs; i++) 981 io_buffer_unmap(ctx, &ctx->user_bufs[i]); 982 kfree(ctx->user_bufs); 983 io_rsrc_data_free(ctx->buf_data); 984 ctx->user_bufs = NULL; 985 ctx->buf_data = NULL; 986 ctx->nr_user_bufs = 0; 987 } 988 989 int io_sqe_buffers_unregister(struct io_ring_ctx *ctx) 990 { 991 unsigned nr = ctx->nr_user_bufs; 992 int ret; 993 994 if (!ctx->buf_data) 995 return -ENXIO; 996 997 /* 998 * Quiesce may unlock ->uring_lock, and while it's not held 999 * prevent new requests using the table. 1000 */ 1001 ctx->nr_user_bufs = 0; 1002 ret = io_rsrc_ref_quiesce(ctx->buf_data, ctx); 1003 ctx->nr_user_bufs = nr; 1004 if (!ret) 1005 __io_sqe_buffers_unregister(ctx); 1006 return ret; 1007 } 1008 1009 /* 1010 * Not super efficient, but this is just a registration time. And we do cache 1011 * the last compound head, so generally we'll only do a full search if we don't 1012 * match that one. 1013 * 1014 * We check if the given compound head page has already been accounted, to 1015 * avoid double accounting it. This allows us to account the full size of the 1016 * page, not just the constituent pages of a huge page. 1017 */ 1018 static bool headpage_already_acct(struct io_ring_ctx *ctx, struct page **pages, 1019 int nr_pages, struct page *hpage) 1020 { 1021 int i, j; 1022 1023 /* check current page array */ 1024 for (i = 0; i < nr_pages; i++) { 1025 if (!PageCompound(pages[i])) 1026 continue; 1027 if (compound_head(pages[i]) == hpage) 1028 return true; 1029 } 1030 1031 /* check previously registered pages */ 1032 for (i = 0; i < ctx->nr_user_bufs; i++) { 1033 struct io_mapped_ubuf *imu = ctx->user_bufs[i]; 1034 1035 for (j = 0; j < imu->nr_bvecs; j++) { 1036 if (!PageCompound(imu->bvec[j].bv_page)) 1037 continue; 1038 if (compound_head(imu->bvec[j].bv_page) == hpage) 1039 return true; 1040 } 1041 } 1042 1043 return false; 1044 } 1045 1046 static int io_buffer_account_pin(struct io_ring_ctx *ctx, struct page **pages, 1047 int nr_pages, struct io_mapped_ubuf *imu, 1048 struct page **last_hpage) 1049 { 1050 int i, ret; 1051 1052 imu->acct_pages = 0; 1053 for (i = 0; i < nr_pages; i++) { 1054 if (!PageCompound(pages[i])) { 1055 imu->acct_pages++; 1056 } else { 1057 struct page *hpage; 1058 1059 hpage = compound_head(pages[i]); 1060 if (hpage == *last_hpage) 1061 continue; 1062 *last_hpage = hpage; 1063 if (headpage_already_acct(ctx, pages, i, hpage)) 1064 continue; 1065 imu->acct_pages += page_size(hpage) >> PAGE_SHIFT; 1066 } 1067 } 1068 1069 if (!imu->acct_pages) 1070 return 0; 1071 1072 ret = io_account_mem(ctx, imu->acct_pages); 1073 if (ret) 1074 imu->acct_pages = 0; 1075 return ret; 1076 } 1077 1078 struct page **io_pin_pages(unsigned long ubuf, unsigned long len, int *npages) 1079 { 1080 unsigned long start, end, nr_pages; 1081 struct vm_area_struct **vmas = NULL; 1082 struct page **pages = NULL; 1083 int i, pret, ret = -ENOMEM; 1084 1085 end = (ubuf + len + PAGE_SIZE - 1) >> PAGE_SHIFT; 1086 start = ubuf >> PAGE_SHIFT; 1087 nr_pages = end - start; 1088 1089 pages = kvmalloc_array(nr_pages, sizeof(struct page *), GFP_KERNEL); 1090 if (!pages) 1091 goto done; 1092 1093 vmas = kvmalloc_array(nr_pages, sizeof(struct vm_area_struct *), 1094 GFP_KERNEL); 1095 if (!vmas) 1096 goto done; 1097 1098 ret = 0; 1099 mmap_read_lock(current->mm); 1100 pret = pin_user_pages(ubuf, nr_pages, FOLL_WRITE | FOLL_LONGTERM, 1101 pages, vmas); 1102 if (pret == nr_pages) { 1103 struct file *file = vmas[0]->vm_file; 1104 1105 /* don't support file backed memory */ 1106 for (i = 0; i < nr_pages; i++) { 1107 if (vmas[i]->vm_file != file) { 1108 ret = -EINVAL; 1109 break; 1110 } 1111 if (!file) 1112 continue; 1113 if (!vma_is_shmem(vmas[i]) && !is_file_hugepages(file)) { 1114 ret = -EOPNOTSUPP; 1115 break; 1116 } 1117 } 1118 *npages = nr_pages; 1119 } else { 1120 ret = pret < 0 ? pret : -EFAULT; 1121 } 1122 mmap_read_unlock(current->mm); 1123 if (ret) { 1124 /* 1125 * if we did partial map, or found file backed vmas, 1126 * release any pages we did get 1127 */ 1128 if (pret > 0) 1129 unpin_user_pages(pages, pret); 1130 goto done; 1131 } 1132 ret = 0; 1133 done: 1134 kvfree(vmas); 1135 if (ret < 0) { 1136 kvfree(pages); 1137 pages = ERR_PTR(ret); 1138 } 1139 return pages; 1140 } 1141 1142 static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov, 1143 struct io_mapped_ubuf **pimu, 1144 struct page **last_hpage) 1145 { 1146 struct io_mapped_ubuf *imu = NULL; 1147 struct page **pages = NULL; 1148 unsigned long off; 1149 size_t size; 1150 int ret, nr_pages, i; 1151 struct folio *folio = NULL; 1152 1153 *pimu = ctx->dummy_ubuf; 1154 if (!iov->iov_base) 1155 return 0; 1156 1157 ret = -ENOMEM; 1158 pages = io_pin_pages((unsigned long) iov->iov_base, iov->iov_len, 1159 &nr_pages); 1160 if (IS_ERR(pages)) { 1161 ret = PTR_ERR(pages); 1162 pages = NULL; 1163 goto done; 1164 } 1165 1166 /* If it's a huge page, try to coalesce them into a single bvec entry */ 1167 if (nr_pages > 1) { 1168 folio = page_folio(pages[0]); 1169 for (i = 1; i < nr_pages; i++) { 1170 if (page_folio(pages[i]) != folio) { 1171 folio = NULL; 1172 break; 1173 } 1174 } 1175 if (folio) { 1176 /* 1177 * The pages are bound to the folio, it doesn't 1178 * actually unpin them but drops all but one reference, 1179 * which is usually put down by io_buffer_unmap(). 1180 * Note, needs a better helper. 1181 */ 1182 unpin_user_pages(&pages[1], nr_pages - 1); 1183 nr_pages = 1; 1184 } 1185 } 1186 1187 imu = kvmalloc(struct_size(imu, bvec, nr_pages), GFP_KERNEL); 1188 if (!imu) 1189 goto done; 1190 1191 ret = io_buffer_account_pin(ctx, pages, nr_pages, imu, last_hpage); 1192 if (ret) { 1193 unpin_user_pages(pages, nr_pages); 1194 goto done; 1195 } 1196 1197 off = (unsigned long) iov->iov_base & ~PAGE_MASK; 1198 size = iov->iov_len; 1199 /* store original address for later verification */ 1200 imu->ubuf = (unsigned long) iov->iov_base; 1201 imu->ubuf_end = imu->ubuf + iov->iov_len; 1202 imu->nr_bvecs = nr_pages; 1203 *pimu = imu; 1204 ret = 0; 1205 1206 if (folio) { 1207 bvec_set_page(&imu->bvec[0], pages[0], size, off); 1208 goto done; 1209 } 1210 for (i = 0; i < nr_pages; i++) { 1211 size_t vec_len; 1212 1213 vec_len = min_t(size_t, size, PAGE_SIZE - off); 1214 bvec_set_page(&imu->bvec[i], pages[i], vec_len, off); 1215 off = 0; 1216 size -= vec_len; 1217 } 1218 done: 1219 if (ret) 1220 kvfree(imu); 1221 kvfree(pages); 1222 return ret; 1223 } 1224 1225 static int io_buffers_map_alloc(struct io_ring_ctx *ctx, unsigned int nr_args) 1226 { 1227 ctx->user_bufs = kcalloc(nr_args, sizeof(*ctx->user_bufs), GFP_KERNEL); 1228 return ctx->user_bufs ? 0 : -ENOMEM; 1229 } 1230 1231 int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg, 1232 unsigned int nr_args, u64 __user *tags) 1233 { 1234 struct page *last_hpage = NULL; 1235 struct io_rsrc_data *data; 1236 int i, ret; 1237 struct iovec iov; 1238 1239 BUILD_BUG_ON(IORING_MAX_REG_BUFFERS >= (1u << 16)); 1240 1241 if (ctx->user_bufs) 1242 return -EBUSY; 1243 if (!nr_args || nr_args > IORING_MAX_REG_BUFFERS) 1244 return -EINVAL; 1245 ret = io_rsrc_data_alloc(ctx, io_rsrc_buf_put, tags, nr_args, &data); 1246 if (ret) 1247 return ret; 1248 ret = io_buffers_map_alloc(ctx, nr_args); 1249 if (ret) { 1250 io_rsrc_data_free(data); 1251 return ret; 1252 } 1253 1254 for (i = 0; i < nr_args; i++, ctx->nr_user_bufs++) { 1255 if (arg) { 1256 ret = io_copy_iov(ctx, &iov, arg, i); 1257 if (ret) 1258 break; 1259 ret = io_buffer_validate(&iov); 1260 if (ret) 1261 break; 1262 } else { 1263 memset(&iov, 0, sizeof(iov)); 1264 } 1265 1266 if (!iov.iov_base && *io_get_tag_slot(data, i)) { 1267 ret = -EINVAL; 1268 break; 1269 } 1270 1271 ret = io_sqe_buffer_register(ctx, &iov, &ctx->user_bufs[i], 1272 &last_hpage); 1273 if (ret) 1274 break; 1275 } 1276 1277 WARN_ON_ONCE(ctx->buf_data); 1278 1279 ctx->buf_data = data; 1280 if (ret) 1281 __io_sqe_buffers_unregister(ctx); 1282 return ret; 1283 } 1284 1285 int io_import_fixed(int ddir, struct iov_iter *iter, 1286 struct io_mapped_ubuf *imu, 1287 u64 buf_addr, size_t len) 1288 { 1289 u64 buf_end; 1290 size_t offset; 1291 1292 if (WARN_ON_ONCE(!imu)) 1293 return -EFAULT; 1294 if (unlikely(check_add_overflow(buf_addr, (u64)len, &buf_end))) 1295 return -EFAULT; 1296 /* not inside the mapped region */ 1297 if (unlikely(buf_addr < imu->ubuf || buf_end > imu->ubuf_end)) 1298 return -EFAULT; 1299 1300 /* 1301 * Might not be a start of buffer, set size appropriately 1302 * and advance us to the beginning. 1303 */ 1304 offset = buf_addr - imu->ubuf; 1305 iov_iter_bvec(iter, ddir, imu->bvec, imu->nr_bvecs, offset + len); 1306 1307 if (offset) { 1308 /* 1309 * Don't use iov_iter_advance() here, as it's really slow for 1310 * using the latter parts of a big fixed buffer - it iterates 1311 * over each segment manually. We can cheat a bit here, because 1312 * we know that: 1313 * 1314 * 1) it's a BVEC iter, we set it up 1315 * 2) all bvecs are PAGE_SIZE in size, except potentially the 1316 * first and last bvec 1317 * 1318 * So just find our index, and adjust the iterator afterwards. 1319 * If the offset is within the first bvec (or the whole first 1320 * bvec, just use iov_iter_advance(). This makes it easier 1321 * since we can just skip the first segment, which may not 1322 * be PAGE_SIZE aligned. 1323 */ 1324 const struct bio_vec *bvec = imu->bvec; 1325 1326 if (offset <= bvec->bv_len) { 1327 /* 1328 * Note, huge pages buffers consists of one large 1329 * bvec entry and should always go this way. The other 1330 * branch doesn't expect non PAGE_SIZE'd chunks. 1331 */ 1332 iter->bvec = bvec; 1333 iter->nr_segs = bvec->bv_len; 1334 iter->count -= offset; 1335 iter->iov_offset = offset; 1336 } else { 1337 unsigned long seg_skip; 1338 1339 /* skip first vec */ 1340 offset -= bvec->bv_len; 1341 seg_skip = 1 + (offset >> PAGE_SHIFT); 1342 1343 iter->bvec = bvec + seg_skip; 1344 iter->nr_segs -= seg_skip; 1345 iter->count -= bvec->bv_len + offset; 1346 iter->iov_offset = offset & ~PAGE_MASK; 1347 } 1348 } 1349 1350 return 0; 1351 } 1352