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 #define IO_RSRC_REF_BATCH 100 31 32 /* only define max */ 33 #define IORING_MAX_FIXED_FILES (1U << 20) 34 #define IORING_MAX_REG_BUFFERS (1U << 14) 35 36 void io_rsrc_refs_drop(struct io_ring_ctx *ctx) 37 __must_hold(&ctx->uring_lock) 38 { 39 if (ctx->rsrc_cached_refs) { 40 io_rsrc_put_node(ctx->rsrc_node, ctx->rsrc_cached_refs); 41 ctx->rsrc_cached_refs = 0; 42 } 43 } 44 45 static inline void __io_unaccount_mem(struct user_struct *user, 46 unsigned long nr_pages) 47 { 48 atomic_long_sub(nr_pages, &user->locked_vm); 49 } 50 51 static inline int __io_account_mem(struct user_struct *user, 52 unsigned long nr_pages) 53 { 54 unsigned long page_limit, cur_pages, new_pages; 55 56 /* Don't allow more pages than we can safely lock */ 57 page_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; 58 59 do { 60 cur_pages = atomic_long_read(&user->locked_vm); 61 new_pages = cur_pages + nr_pages; 62 if (new_pages > page_limit) 63 return -ENOMEM; 64 } while (atomic_long_cmpxchg(&user->locked_vm, cur_pages, 65 new_pages) != cur_pages); 66 67 return 0; 68 } 69 70 static void io_unaccount_mem(struct io_ring_ctx *ctx, unsigned long nr_pages) 71 { 72 if (ctx->user) 73 __io_unaccount_mem(ctx->user, nr_pages); 74 75 if (ctx->mm_account) 76 atomic64_sub(nr_pages, &ctx->mm_account->pinned_vm); 77 } 78 79 static int io_account_mem(struct io_ring_ctx *ctx, unsigned long nr_pages) 80 { 81 int ret; 82 83 if (ctx->user) { 84 ret = __io_account_mem(ctx->user, nr_pages); 85 if (ret) 86 return ret; 87 } 88 89 if (ctx->mm_account) 90 atomic64_add(nr_pages, &ctx->mm_account->pinned_vm); 91 92 return 0; 93 } 94 95 static int io_copy_iov(struct io_ring_ctx *ctx, struct iovec *dst, 96 void __user *arg, unsigned index) 97 { 98 struct iovec __user *src; 99 100 #ifdef CONFIG_COMPAT 101 if (ctx->compat) { 102 struct compat_iovec __user *ciovs; 103 struct compat_iovec ciov; 104 105 ciovs = (struct compat_iovec __user *) arg; 106 if (copy_from_user(&ciov, &ciovs[index], sizeof(ciov))) 107 return -EFAULT; 108 109 dst->iov_base = u64_to_user_ptr((u64)ciov.iov_base); 110 dst->iov_len = ciov.iov_len; 111 return 0; 112 } 113 #endif 114 src = (struct iovec __user *) arg; 115 if (copy_from_user(dst, &src[index], sizeof(*dst))) 116 return -EFAULT; 117 return 0; 118 } 119 120 static int io_buffer_validate(struct iovec *iov) 121 { 122 unsigned long tmp, acct_len = iov->iov_len + (PAGE_SIZE - 1); 123 124 /* 125 * Don't impose further limits on the size and buffer 126 * constraints here, we'll -EINVAL later when IO is 127 * submitted if they are wrong. 128 */ 129 if (!iov->iov_base) 130 return iov->iov_len ? -EFAULT : 0; 131 if (!iov->iov_len) 132 return -EFAULT; 133 134 /* arbitrary limit, but we need something */ 135 if (iov->iov_len > SZ_1G) 136 return -EFAULT; 137 138 if (check_add_overflow((unsigned long)iov->iov_base, acct_len, &tmp)) 139 return -EOVERFLOW; 140 141 return 0; 142 } 143 144 static void io_buffer_unmap(struct io_ring_ctx *ctx, struct io_mapped_ubuf **slot) 145 { 146 struct io_mapped_ubuf *imu = *slot; 147 unsigned int i; 148 149 if (imu != ctx->dummy_ubuf) { 150 for (i = 0; i < imu->nr_bvecs; i++) 151 unpin_user_page(imu->bvec[i].bv_page); 152 if (imu->acct_pages) 153 io_unaccount_mem(ctx, imu->acct_pages); 154 kvfree(imu); 155 } 156 *slot = NULL; 157 } 158 159 void io_rsrc_refs_refill(struct io_ring_ctx *ctx) 160 __must_hold(&ctx->uring_lock) 161 { 162 ctx->rsrc_cached_refs += IO_RSRC_REF_BATCH; 163 percpu_ref_get_many(&ctx->rsrc_node->refs, IO_RSRC_REF_BATCH); 164 } 165 166 static void __io_rsrc_put_work(struct io_rsrc_node *ref_node) 167 { 168 struct io_rsrc_data *rsrc_data = ref_node->rsrc_data; 169 struct io_ring_ctx *ctx = rsrc_data->ctx; 170 struct io_rsrc_put *prsrc, *tmp; 171 172 list_for_each_entry_safe(prsrc, tmp, &ref_node->rsrc_list, list) { 173 list_del(&prsrc->list); 174 175 if (prsrc->tag) { 176 if (ctx->flags & IORING_SETUP_IOPOLL) { 177 mutex_lock(&ctx->uring_lock); 178 io_post_aux_cqe(ctx, prsrc->tag, 0, 0); 179 mutex_unlock(&ctx->uring_lock); 180 } else { 181 io_post_aux_cqe(ctx, prsrc->tag, 0, 0); 182 } 183 } 184 185 rsrc_data->do_put(ctx, prsrc); 186 kfree(prsrc); 187 } 188 189 io_rsrc_node_destroy(ref_node); 190 if (atomic_dec_and_test(&rsrc_data->refs)) 191 complete(&rsrc_data->done); 192 } 193 194 void io_rsrc_put_work(struct work_struct *work) 195 { 196 struct io_ring_ctx *ctx; 197 struct llist_node *node; 198 199 ctx = container_of(work, struct io_ring_ctx, rsrc_put_work.work); 200 node = llist_del_all(&ctx->rsrc_put_llist); 201 202 while (node) { 203 struct io_rsrc_node *ref_node; 204 struct llist_node *next = node->next; 205 206 ref_node = llist_entry(node, struct io_rsrc_node, llist); 207 __io_rsrc_put_work(ref_node); 208 node = next; 209 } 210 } 211 212 void io_wait_rsrc_data(struct io_rsrc_data *data) 213 { 214 if (data && !atomic_dec_and_test(&data->refs)) 215 wait_for_completion(&data->done); 216 } 217 218 void io_rsrc_node_destroy(struct io_rsrc_node *ref_node) 219 { 220 percpu_ref_exit(&ref_node->refs); 221 kfree(ref_node); 222 } 223 224 static __cold void io_rsrc_node_ref_zero(struct percpu_ref *ref) 225 { 226 struct io_rsrc_node *node = container_of(ref, struct io_rsrc_node, refs); 227 struct io_ring_ctx *ctx = node->rsrc_data->ctx; 228 unsigned long flags; 229 bool first_add = false; 230 unsigned long delay = HZ; 231 232 spin_lock_irqsave(&ctx->rsrc_ref_lock, flags); 233 node->done = true; 234 235 /* if we are mid-quiesce then do not delay */ 236 if (node->rsrc_data->quiesce) 237 delay = 0; 238 239 while (!list_empty(&ctx->rsrc_ref_list)) { 240 node = list_first_entry(&ctx->rsrc_ref_list, 241 struct io_rsrc_node, node); 242 /* recycle ref nodes in order */ 243 if (!node->done) 244 break; 245 list_del(&node->node); 246 first_add |= llist_add(&node->llist, &ctx->rsrc_put_llist); 247 } 248 spin_unlock_irqrestore(&ctx->rsrc_ref_lock, flags); 249 250 if (first_add) 251 mod_delayed_work(system_wq, &ctx->rsrc_put_work, delay); 252 } 253 254 static struct io_rsrc_node *io_rsrc_node_alloc(void) 255 { 256 struct io_rsrc_node *ref_node; 257 258 ref_node = kzalloc(sizeof(*ref_node), GFP_KERNEL); 259 if (!ref_node) 260 return NULL; 261 262 if (percpu_ref_init(&ref_node->refs, io_rsrc_node_ref_zero, 263 0, GFP_KERNEL)) { 264 kfree(ref_node); 265 return NULL; 266 } 267 INIT_LIST_HEAD(&ref_node->node); 268 INIT_LIST_HEAD(&ref_node->rsrc_list); 269 ref_node->done = false; 270 return ref_node; 271 } 272 273 void io_rsrc_node_switch(struct io_ring_ctx *ctx, 274 struct io_rsrc_data *data_to_kill) 275 __must_hold(&ctx->uring_lock) 276 { 277 WARN_ON_ONCE(!ctx->rsrc_backup_node); 278 WARN_ON_ONCE(data_to_kill && !ctx->rsrc_node); 279 280 io_rsrc_refs_drop(ctx); 281 282 if (data_to_kill) { 283 struct io_rsrc_node *rsrc_node = ctx->rsrc_node; 284 285 rsrc_node->rsrc_data = data_to_kill; 286 spin_lock_irq(&ctx->rsrc_ref_lock); 287 list_add_tail(&rsrc_node->node, &ctx->rsrc_ref_list); 288 spin_unlock_irq(&ctx->rsrc_ref_lock); 289 290 atomic_inc(&data_to_kill->refs); 291 percpu_ref_kill(&rsrc_node->refs); 292 ctx->rsrc_node = NULL; 293 } 294 295 if (!ctx->rsrc_node) { 296 ctx->rsrc_node = ctx->rsrc_backup_node; 297 ctx->rsrc_backup_node = NULL; 298 } 299 } 300 301 int io_rsrc_node_switch_start(struct io_ring_ctx *ctx) 302 { 303 if (ctx->rsrc_backup_node) 304 return 0; 305 ctx->rsrc_backup_node = io_rsrc_node_alloc(); 306 return ctx->rsrc_backup_node ? 0 : -ENOMEM; 307 } 308 309 __cold static int io_rsrc_ref_quiesce(struct io_rsrc_data *data, 310 struct io_ring_ctx *ctx) 311 { 312 int ret; 313 314 /* As we may drop ->uring_lock, other task may have started quiesce */ 315 if (data->quiesce) 316 return -ENXIO; 317 318 data->quiesce = true; 319 do { 320 ret = io_rsrc_node_switch_start(ctx); 321 if (ret) 322 break; 323 io_rsrc_node_switch(ctx, data); 324 325 /* kill initial ref, already quiesced if zero */ 326 if (atomic_dec_and_test(&data->refs)) 327 break; 328 mutex_unlock(&ctx->uring_lock); 329 flush_delayed_work(&ctx->rsrc_put_work); 330 ret = wait_for_completion_interruptible(&data->done); 331 if (!ret) { 332 mutex_lock(&ctx->uring_lock); 333 if (atomic_read(&data->refs) > 0) { 334 /* 335 * it has been revived by another thread while 336 * we were unlocked 337 */ 338 mutex_unlock(&ctx->uring_lock); 339 } else { 340 break; 341 } 342 } 343 344 atomic_inc(&data->refs); 345 /* wait for all works potentially completing data->done */ 346 flush_delayed_work(&ctx->rsrc_put_work); 347 reinit_completion(&data->done); 348 349 ret = io_run_task_work_sig(); 350 mutex_lock(&ctx->uring_lock); 351 } while (ret >= 0); 352 data->quiesce = false; 353 354 return ret; 355 } 356 357 static void io_free_page_table(void **table, size_t size) 358 { 359 unsigned i, nr_tables = DIV_ROUND_UP(size, PAGE_SIZE); 360 361 for (i = 0; i < nr_tables; i++) 362 kfree(table[i]); 363 kfree(table); 364 } 365 366 static void io_rsrc_data_free(struct io_rsrc_data *data) 367 { 368 size_t size = data->nr * sizeof(data->tags[0][0]); 369 370 if (data->tags) 371 io_free_page_table((void **)data->tags, size); 372 kfree(data); 373 } 374 375 static __cold void **io_alloc_page_table(size_t size) 376 { 377 unsigned i, nr_tables = DIV_ROUND_UP(size, PAGE_SIZE); 378 size_t init_size = size; 379 void **table; 380 381 table = kcalloc(nr_tables, sizeof(*table), GFP_KERNEL_ACCOUNT); 382 if (!table) 383 return NULL; 384 385 for (i = 0; i < nr_tables; i++) { 386 unsigned int this_size = min_t(size_t, size, PAGE_SIZE); 387 388 table[i] = kzalloc(this_size, GFP_KERNEL_ACCOUNT); 389 if (!table[i]) { 390 io_free_page_table(table, init_size); 391 return NULL; 392 } 393 size -= this_size; 394 } 395 return table; 396 } 397 398 __cold static int io_rsrc_data_alloc(struct io_ring_ctx *ctx, 399 rsrc_put_fn *do_put, u64 __user *utags, 400 unsigned nr, struct io_rsrc_data **pdata) 401 { 402 struct io_rsrc_data *data; 403 int ret = -ENOMEM; 404 unsigned i; 405 406 data = kzalloc(sizeof(*data), GFP_KERNEL); 407 if (!data) 408 return -ENOMEM; 409 data->tags = (u64 **)io_alloc_page_table(nr * sizeof(data->tags[0][0])); 410 if (!data->tags) { 411 kfree(data); 412 return -ENOMEM; 413 } 414 415 data->nr = nr; 416 data->ctx = ctx; 417 data->do_put = do_put; 418 if (utags) { 419 ret = -EFAULT; 420 for (i = 0; i < nr; i++) { 421 u64 *tag_slot = io_get_tag_slot(data, i); 422 423 if (copy_from_user(tag_slot, &utags[i], 424 sizeof(*tag_slot))) 425 goto fail; 426 } 427 } 428 429 atomic_set(&data->refs, 1); 430 init_completion(&data->done); 431 *pdata = data; 432 return 0; 433 fail: 434 io_rsrc_data_free(data); 435 return ret; 436 } 437 438 static int __io_sqe_files_update(struct io_ring_ctx *ctx, 439 struct io_uring_rsrc_update2 *up, 440 unsigned nr_args) 441 { 442 u64 __user *tags = u64_to_user_ptr(up->tags); 443 __s32 __user *fds = u64_to_user_ptr(up->data); 444 struct io_rsrc_data *data = ctx->file_data; 445 struct io_fixed_file *file_slot; 446 struct file *file; 447 int fd, i, err = 0; 448 unsigned int done; 449 bool needs_switch = false; 450 451 if (!ctx->file_data) 452 return -ENXIO; 453 if (up->offset + nr_args > ctx->nr_user_files) 454 return -EINVAL; 455 456 for (done = 0; done < nr_args; done++) { 457 u64 tag = 0; 458 459 if ((tags && copy_from_user(&tag, &tags[done], sizeof(tag))) || 460 copy_from_user(&fd, &fds[done], sizeof(fd))) { 461 err = -EFAULT; 462 break; 463 } 464 if ((fd == IORING_REGISTER_FILES_SKIP || fd == -1) && tag) { 465 err = -EINVAL; 466 break; 467 } 468 if (fd == IORING_REGISTER_FILES_SKIP) 469 continue; 470 471 i = array_index_nospec(up->offset + done, ctx->nr_user_files); 472 file_slot = io_fixed_file_slot(&ctx->file_table, i); 473 474 if (file_slot->file_ptr) { 475 file = (struct file *)(file_slot->file_ptr & FFS_MASK); 476 err = io_queue_rsrc_removal(data, i, ctx->rsrc_node, file); 477 if (err) 478 break; 479 file_slot->file_ptr = 0; 480 io_file_bitmap_clear(&ctx->file_table, i); 481 needs_switch = true; 482 } 483 if (fd != -1) { 484 file = fget(fd); 485 if (!file) { 486 err = -EBADF; 487 break; 488 } 489 /* 490 * Don't allow io_uring instances to be registered. If 491 * UNIX isn't enabled, then this causes a reference 492 * cycle and this instance can never get freed. If UNIX 493 * is enabled we'll handle it just fine, but there's 494 * still no point in allowing a ring fd as it doesn't 495 * support regular read/write anyway. 496 */ 497 if (io_is_uring_fops(file)) { 498 fput(file); 499 err = -EBADF; 500 break; 501 } 502 err = io_scm_file_account(ctx, file); 503 if (err) { 504 fput(file); 505 break; 506 } 507 *io_get_tag_slot(data, i) = tag; 508 io_fixed_file_set(file_slot, file); 509 io_file_bitmap_set(&ctx->file_table, i); 510 } 511 } 512 513 if (needs_switch) 514 io_rsrc_node_switch(ctx, data); 515 return done ? done : err; 516 } 517 518 static int __io_sqe_buffers_update(struct io_ring_ctx *ctx, 519 struct io_uring_rsrc_update2 *up, 520 unsigned int nr_args) 521 { 522 u64 __user *tags = u64_to_user_ptr(up->tags); 523 struct iovec iov, __user *iovs = u64_to_user_ptr(up->data); 524 struct page *last_hpage = NULL; 525 bool needs_switch = false; 526 __u32 done; 527 int i, err; 528 529 if (!ctx->buf_data) 530 return -ENXIO; 531 if (up->offset + nr_args > ctx->nr_user_bufs) 532 return -EINVAL; 533 534 for (done = 0; done < nr_args; done++) { 535 struct io_mapped_ubuf *imu; 536 int offset = up->offset + done; 537 u64 tag = 0; 538 539 err = io_copy_iov(ctx, &iov, iovs, done); 540 if (err) 541 break; 542 if (tags && copy_from_user(&tag, &tags[done], sizeof(tag))) { 543 err = -EFAULT; 544 break; 545 } 546 err = io_buffer_validate(&iov); 547 if (err) 548 break; 549 if (!iov.iov_base && tag) { 550 err = -EINVAL; 551 break; 552 } 553 err = io_sqe_buffer_register(ctx, &iov, &imu, &last_hpage); 554 if (err) 555 break; 556 557 i = array_index_nospec(offset, ctx->nr_user_bufs); 558 if (ctx->user_bufs[i] != ctx->dummy_ubuf) { 559 err = io_queue_rsrc_removal(ctx->buf_data, i, 560 ctx->rsrc_node, ctx->user_bufs[i]); 561 if (unlikely(err)) { 562 io_buffer_unmap(ctx, &imu); 563 break; 564 } 565 ctx->user_bufs[i] = ctx->dummy_ubuf; 566 needs_switch = true; 567 } 568 569 ctx->user_bufs[i] = imu; 570 *io_get_tag_slot(ctx->buf_data, offset) = tag; 571 } 572 573 if (needs_switch) 574 io_rsrc_node_switch(ctx, ctx->buf_data); 575 return done ? done : err; 576 } 577 578 static int __io_register_rsrc_update(struct io_ring_ctx *ctx, unsigned type, 579 struct io_uring_rsrc_update2 *up, 580 unsigned nr_args) 581 { 582 __u32 tmp; 583 int err; 584 585 if (check_add_overflow(up->offset, nr_args, &tmp)) 586 return -EOVERFLOW; 587 err = io_rsrc_node_switch_start(ctx); 588 if (err) 589 return err; 590 591 switch (type) { 592 case IORING_RSRC_FILE: 593 return __io_sqe_files_update(ctx, up, nr_args); 594 case IORING_RSRC_BUFFER: 595 return __io_sqe_buffers_update(ctx, up, nr_args); 596 } 597 return -EINVAL; 598 } 599 600 int io_register_files_update(struct io_ring_ctx *ctx, void __user *arg, 601 unsigned nr_args) 602 { 603 struct io_uring_rsrc_update2 up; 604 605 if (!nr_args) 606 return -EINVAL; 607 memset(&up, 0, sizeof(up)); 608 if (copy_from_user(&up, arg, sizeof(struct io_uring_rsrc_update))) 609 return -EFAULT; 610 if (up.resv || up.resv2) 611 return -EINVAL; 612 return __io_register_rsrc_update(ctx, IORING_RSRC_FILE, &up, nr_args); 613 } 614 615 int io_register_rsrc_update(struct io_ring_ctx *ctx, void __user *arg, 616 unsigned size, unsigned type) 617 { 618 struct io_uring_rsrc_update2 up; 619 620 if (size != sizeof(up)) 621 return -EINVAL; 622 if (copy_from_user(&up, arg, sizeof(up))) 623 return -EFAULT; 624 if (!up.nr || up.resv || up.resv2) 625 return -EINVAL; 626 return __io_register_rsrc_update(ctx, type, &up, up.nr); 627 } 628 629 __cold int io_register_rsrc(struct io_ring_ctx *ctx, void __user *arg, 630 unsigned int size, unsigned int type) 631 { 632 struct io_uring_rsrc_register rr; 633 634 /* keep it extendible */ 635 if (size != sizeof(rr)) 636 return -EINVAL; 637 638 memset(&rr, 0, sizeof(rr)); 639 if (copy_from_user(&rr, arg, size)) 640 return -EFAULT; 641 if (!rr.nr || rr.resv2) 642 return -EINVAL; 643 if (rr.flags & ~IORING_RSRC_REGISTER_SPARSE) 644 return -EINVAL; 645 646 switch (type) { 647 case IORING_RSRC_FILE: 648 if (rr.flags & IORING_RSRC_REGISTER_SPARSE && rr.data) 649 break; 650 return io_sqe_files_register(ctx, u64_to_user_ptr(rr.data), 651 rr.nr, u64_to_user_ptr(rr.tags)); 652 case IORING_RSRC_BUFFER: 653 if (rr.flags & IORING_RSRC_REGISTER_SPARSE && rr.data) 654 break; 655 return io_sqe_buffers_register(ctx, u64_to_user_ptr(rr.data), 656 rr.nr, u64_to_user_ptr(rr.tags)); 657 } 658 return -EINVAL; 659 } 660 661 int io_files_update_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) 662 { 663 struct io_rsrc_update *up = io_kiocb_to_cmd(req); 664 665 if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT))) 666 return -EINVAL; 667 if (sqe->rw_flags || sqe->splice_fd_in) 668 return -EINVAL; 669 670 up->offset = READ_ONCE(sqe->off); 671 up->nr_args = READ_ONCE(sqe->len); 672 if (!up->nr_args) 673 return -EINVAL; 674 up->arg = READ_ONCE(sqe->addr); 675 return 0; 676 } 677 678 static int io_files_update_with_index_alloc(struct io_kiocb *req, 679 unsigned int issue_flags) 680 { 681 struct io_rsrc_update *up = io_kiocb_to_cmd(req); 682 __s32 __user *fds = u64_to_user_ptr(up->arg); 683 unsigned int done; 684 struct file *file; 685 int ret, fd; 686 687 if (!req->ctx->file_data) 688 return -ENXIO; 689 690 for (done = 0; done < up->nr_args; done++) { 691 if (copy_from_user(&fd, &fds[done], sizeof(fd))) { 692 ret = -EFAULT; 693 break; 694 } 695 696 file = fget(fd); 697 if (!file) { 698 ret = -EBADF; 699 break; 700 } 701 ret = io_fixed_fd_install(req, issue_flags, file, 702 IORING_FILE_INDEX_ALLOC); 703 if (ret < 0) 704 break; 705 if (copy_to_user(&fds[done], &ret, sizeof(ret))) { 706 __io_close_fixed(req, issue_flags, ret); 707 ret = -EFAULT; 708 break; 709 } 710 } 711 712 if (done) 713 return done; 714 return ret; 715 } 716 717 int io_files_update(struct io_kiocb *req, unsigned int issue_flags) 718 { 719 struct io_rsrc_update *up = io_kiocb_to_cmd(req); 720 struct io_ring_ctx *ctx = req->ctx; 721 struct io_uring_rsrc_update2 up2; 722 int ret; 723 724 up2.offset = up->offset; 725 up2.data = up->arg; 726 up2.nr = 0; 727 up2.tags = 0; 728 up2.resv = 0; 729 up2.resv2 = 0; 730 731 if (up->offset == IORING_FILE_INDEX_ALLOC) { 732 ret = io_files_update_with_index_alloc(req, issue_flags); 733 } else { 734 io_ring_submit_lock(ctx, issue_flags); 735 ret = __io_register_rsrc_update(ctx, IORING_RSRC_FILE, 736 &up2, up->nr_args); 737 io_ring_submit_unlock(ctx, issue_flags); 738 } 739 740 if (ret < 0) 741 req_set_fail(req); 742 io_req_set_res(req, ret, 0); 743 return IOU_OK; 744 } 745 746 int io_queue_rsrc_removal(struct io_rsrc_data *data, unsigned idx, 747 struct io_rsrc_node *node, void *rsrc) 748 { 749 u64 *tag_slot = io_get_tag_slot(data, idx); 750 struct io_rsrc_put *prsrc; 751 752 prsrc = kzalloc(sizeof(*prsrc), GFP_KERNEL); 753 if (!prsrc) 754 return -ENOMEM; 755 756 prsrc->tag = *tag_slot; 757 *tag_slot = 0; 758 prsrc->rsrc = rsrc; 759 list_add(&prsrc->list, &node->rsrc_list); 760 return 0; 761 } 762 763 void __io_sqe_files_unregister(struct io_ring_ctx *ctx) 764 { 765 #if !defined(IO_URING_SCM_ALL) 766 int i; 767 768 for (i = 0; i < ctx->nr_user_files; i++) { 769 struct file *file = io_file_from_index(&ctx->file_table, i); 770 771 if (!file) 772 continue; 773 if (io_fixed_file_slot(&ctx->file_table, i)->file_ptr & FFS_SCM) 774 continue; 775 io_file_bitmap_clear(&ctx->file_table, i); 776 fput(file); 777 } 778 #endif 779 780 #if defined(CONFIG_UNIX) 781 if (ctx->ring_sock) { 782 struct sock *sock = ctx->ring_sock->sk; 783 struct sk_buff *skb; 784 785 while ((skb = skb_dequeue(&sock->sk_receive_queue)) != NULL) 786 kfree_skb(skb); 787 } 788 #endif 789 io_free_file_tables(&ctx->file_table); 790 io_rsrc_data_free(ctx->file_data); 791 ctx->file_data = NULL; 792 ctx->nr_user_files = 0; 793 } 794 795 int io_sqe_files_unregister(struct io_ring_ctx *ctx) 796 { 797 unsigned nr = ctx->nr_user_files; 798 int ret; 799 800 if (!ctx->file_data) 801 return -ENXIO; 802 803 /* 804 * Quiesce may unlock ->uring_lock, and while it's not held 805 * prevent new requests using the table. 806 */ 807 ctx->nr_user_files = 0; 808 ret = io_rsrc_ref_quiesce(ctx->file_data, ctx); 809 ctx->nr_user_files = nr; 810 if (!ret) 811 __io_sqe_files_unregister(ctx); 812 return ret; 813 } 814 815 /* 816 * Ensure the UNIX gc is aware of our file set, so we are certain that 817 * the io_uring can be safely unregistered on process exit, even if we have 818 * loops in the file referencing. We account only files that can hold other 819 * files because otherwise they can't form a loop and so are not interesting 820 * for GC. 821 */ 822 int __io_scm_file_account(struct io_ring_ctx *ctx, struct file *file) 823 { 824 #if defined(CONFIG_UNIX) 825 struct sock *sk = ctx->ring_sock->sk; 826 struct sk_buff_head *head = &sk->sk_receive_queue; 827 struct scm_fp_list *fpl; 828 struct sk_buff *skb; 829 830 if (likely(!io_file_need_scm(file))) 831 return 0; 832 833 /* 834 * See if we can merge this file into an existing skb SCM_RIGHTS 835 * file set. If there's no room, fall back to allocating a new skb 836 * and filling it in. 837 */ 838 spin_lock_irq(&head->lock); 839 skb = skb_peek(head); 840 if (skb && UNIXCB(skb).fp->count < SCM_MAX_FD) 841 __skb_unlink(skb, head); 842 else 843 skb = NULL; 844 spin_unlock_irq(&head->lock); 845 846 if (!skb) { 847 fpl = kzalloc(sizeof(*fpl), GFP_KERNEL); 848 if (!fpl) 849 return -ENOMEM; 850 851 skb = alloc_skb(0, GFP_KERNEL); 852 if (!skb) { 853 kfree(fpl); 854 return -ENOMEM; 855 } 856 857 fpl->user = get_uid(current_user()); 858 fpl->max = SCM_MAX_FD; 859 fpl->count = 0; 860 861 UNIXCB(skb).fp = fpl; 862 skb->sk = sk; 863 skb->destructor = unix_destruct_scm; 864 refcount_add(skb->truesize, &sk->sk_wmem_alloc); 865 } 866 867 fpl = UNIXCB(skb).fp; 868 fpl->fp[fpl->count++] = get_file(file); 869 unix_inflight(fpl->user, file); 870 skb_queue_head(head, skb); 871 fput(file); 872 #endif 873 return 0; 874 } 875 876 static void io_rsrc_file_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc) 877 { 878 struct file *file = prsrc->file; 879 #if defined(CONFIG_UNIX) 880 struct sock *sock = ctx->ring_sock->sk; 881 struct sk_buff_head list, *head = &sock->sk_receive_queue; 882 struct sk_buff *skb; 883 int i; 884 885 if (!io_file_need_scm(file)) { 886 fput(file); 887 return; 888 } 889 890 __skb_queue_head_init(&list); 891 892 /* 893 * Find the skb that holds this file in its SCM_RIGHTS. When found, 894 * remove this entry and rearrange the file array. 895 */ 896 skb = skb_dequeue(head); 897 while (skb) { 898 struct scm_fp_list *fp; 899 900 fp = UNIXCB(skb).fp; 901 for (i = 0; i < fp->count; i++) { 902 int left; 903 904 if (fp->fp[i] != file) 905 continue; 906 907 unix_notinflight(fp->user, fp->fp[i]); 908 left = fp->count - 1 - i; 909 if (left) { 910 memmove(&fp->fp[i], &fp->fp[i + 1], 911 left * sizeof(struct file *)); 912 } 913 fp->count--; 914 if (!fp->count) { 915 kfree_skb(skb); 916 skb = NULL; 917 } else { 918 __skb_queue_tail(&list, skb); 919 } 920 fput(file); 921 file = NULL; 922 break; 923 } 924 925 if (!file) 926 break; 927 928 __skb_queue_tail(&list, skb); 929 930 skb = skb_dequeue(head); 931 } 932 933 if (skb_peek(&list)) { 934 spin_lock_irq(&head->lock); 935 while ((skb = __skb_dequeue(&list)) != NULL) 936 __skb_queue_tail(head, skb); 937 spin_unlock_irq(&head->lock); 938 } 939 #else 940 fput(file); 941 #endif 942 } 943 944 int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg, 945 unsigned nr_args, u64 __user *tags) 946 { 947 __s32 __user *fds = (__s32 __user *) arg; 948 struct file *file; 949 int fd, ret; 950 unsigned i; 951 952 if (ctx->file_data) 953 return -EBUSY; 954 if (!nr_args) 955 return -EINVAL; 956 if (nr_args > IORING_MAX_FIXED_FILES) 957 return -EMFILE; 958 if (nr_args > rlimit(RLIMIT_NOFILE)) 959 return -EMFILE; 960 ret = io_rsrc_node_switch_start(ctx); 961 if (ret) 962 return ret; 963 ret = io_rsrc_data_alloc(ctx, io_rsrc_file_put, tags, nr_args, 964 &ctx->file_data); 965 if (ret) 966 return ret; 967 968 if (!io_alloc_file_tables(&ctx->file_table, nr_args)) { 969 io_rsrc_data_free(ctx->file_data); 970 ctx->file_data = NULL; 971 return -ENOMEM; 972 } 973 974 for (i = 0; i < nr_args; i++, ctx->nr_user_files++) { 975 struct io_fixed_file *file_slot; 976 977 if (fds && copy_from_user(&fd, &fds[i], sizeof(fd))) { 978 ret = -EFAULT; 979 goto fail; 980 } 981 /* allow sparse sets */ 982 if (!fds || fd == -1) { 983 ret = -EINVAL; 984 if (unlikely(*io_get_tag_slot(ctx->file_data, i))) 985 goto fail; 986 continue; 987 } 988 989 file = fget(fd); 990 ret = -EBADF; 991 if (unlikely(!file)) 992 goto fail; 993 994 /* 995 * Don't allow io_uring instances to be registered. If UNIX 996 * isn't enabled, then this causes a reference cycle and this 997 * instance can never get freed. If UNIX is enabled we'll 998 * handle it just fine, but there's still no point in allowing 999 * a ring fd as it doesn't support regular read/write anyway. 1000 */ 1001 if (io_is_uring_fops(file)) { 1002 fput(file); 1003 goto fail; 1004 } 1005 ret = io_scm_file_account(ctx, file); 1006 if (ret) { 1007 fput(file); 1008 goto fail; 1009 } 1010 file_slot = io_fixed_file_slot(&ctx->file_table, i); 1011 io_fixed_file_set(file_slot, file); 1012 io_file_bitmap_set(&ctx->file_table, i); 1013 } 1014 1015 io_rsrc_node_switch(ctx, NULL); 1016 return 0; 1017 fail: 1018 __io_sqe_files_unregister(ctx); 1019 return ret; 1020 } 1021 1022 static void io_rsrc_buf_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc) 1023 { 1024 io_buffer_unmap(ctx, &prsrc->buf); 1025 prsrc->buf = NULL; 1026 } 1027 1028 void __io_sqe_buffers_unregister(struct io_ring_ctx *ctx) 1029 { 1030 unsigned int i; 1031 1032 for (i = 0; i < ctx->nr_user_bufs; i++) 1033 io_buffer_unmap(ctx, &ctx->user_bufs[i]); 1034 kfree(ctx->user_bufs); 1035 io_rsrc_data_free(ctx->buf_data); 1036 ctx->user_bufs = NULL; 1037 ctx->buf_data = NULL; 1038 ctx->nr_user_bufs = 0; 1039 } 1040 1041 int io_sqe_buffers_unregister(struct io_ring_ctx *ctx) 1042 { 1043 unsigned nr = ctx->nr_user_bufs; 1044 int ret; 1045 1046 if (!ctx->buf_data) 1047 return -ENXIO; 1048 1049 /* 1050 * Quiesce may unlock ->uring_lock, and while it's not held 1051 * prevent new requests using the table. 1052 */ 1053 ctx->nr_user_bufs = 0; 1054 ret = io_rsrc_ref_quiesce(ctx->buf_data, ctx); 1055 ctx->nr_user_bufs = nr; 1056 if (!ret) 1057 __io_sqe_buffers_unregister(ctx); 1058 return ret; 1059 } 1060 1061 /* 1062 * Not super efficient, but this is just a registration time. And we do cache 1063 * the last compound head, so generally we'll only do a full search if we don't 1064 * match that one. 1065 * 1066 * We check if the given compound head page has already been accounted, to 1067 * avoid double accounting it. This allows us to account the full size of the 1068 * page, not just the constituent pages of a huge page. 1069 */ 1070 static bool headpage_already_acct(struct io_ring_ctx *ctx, struct page **pages, 1071 int nr_pages, struct page *hpage) 1072 { 1073 int i, j; 1074 1075 /* check current page array */ 1076 for (i = 0; i < nr_pages; i++) { 1077 if (!PageCompound(pages[i])) 1078 continue; 1079 if (compound_head(pages[i]) == hpage) 1080 return true; 1081 } 1082 1083 /* check previously registered pages */ 1084 for (i = 0; i < ctx->nr_user_bufs; i++) { 1085 struct io_mapped_ubuf *imu = ctx->user_bufs[i]; 1086 1087 for (j = 0; j < imu->nr_bvecs; j++) { 1088 if (!PageCompound(imu->bvec[j].bv_page)) 1089 continue; 1090 if (compound_head(imu->bvec[j].bv_page) == hpage) 1091 return true; 1092 } 1093 } 1094 1095 return false; 1096 } 1097 1098 static int io_buffer_account_pin(struct io_ring_ctx *ctx, struct page **pages, 1099 int nr_pages, struct io_mapped_ubuf *imu, 1100 struct page **last_hpage) 1101 { 1102 int i, ret; 1103 1104 imu->acct_pages = 0; 1105 for (i = 0; i < nr_pages; i++) { 1106 if (!PageCompound(pages[i])) { 1107 imu->acct_pages++; 1108 } else { 1109 struct page *hpage; 1110 1111 hpage = compound_head(pages[i]); 1112 if (hpage == *last_hpage) 1113 continue; 1114 *last_hpage = hpage; 1115 if (headpage_already_acct(ctx, pages, i, hpage)) 1116 continue; 1117 imu->acct_pages += page_size(hpage) >> PAGE_SHIFT; 1118 } 1119 } 1120 1121 if (!imu->acct_pages) 1122 return 0; 1123 1124 ret = io_account_mem(ctx, imu->acct_pages); 1125 if (ret) 1126 imu->acct_pages = 0; 1127 return ret; 1128 } 1129 1130 struct page **io_pin_pages(unsigned long ubuf, unsigned long len, int *npages) 1131 { 1132 unsigned long start, end, nr_pages; 1133 struct vm_area_struct **vmas = NULL; 1134 struct page **pages = NULL; 1135 int i, pret, ret = -ENOMEM; 1136 1137 end = (ubuf + len + PAGE_SIZE - 1) >> PAGE_SHIFT; 1138 start = ubuf >> PAGE_SHIFT; 1139 nr_pages = end - start; 1140 1141 pages = kvmalloc_array(nr_pages, sizeof(struct page *), GFP_KERNEL); 1142 if (!pages) 1143 goto done; 1144 1145 vmas = kvmalloc_array(nr_pages, sizeof(struct vm_area_struct *), 1146 GFP_KERNEL); 1147 if (!vmas) 1148 goto done; 1149 1150 ret = 0; 1151 mmap_read_lock(current->mm); 1152 pret = pin_user_pages(ubuf, nr_pages, FOLL_WRITE | FOLL_LONGTERM, 1153 pages, vmas); 1154 if (pret == nr_pages) { 1155 /* don't support file backed memory */ 1156 for (i = 0; i < nr_pages; i++) { 1157 struct vm_area_struct *vma = vmas[i]; 1158 1159 if (vma_is_shmem(vma)) 1160 continue; 1161 if (vma->vm_file && 1162 !is_file_hugepages(vma->vm_file)) { 1163 ret = -EOPNOTSUPP; 1164 break; 1165 } 1166 } 1167 *npages = nr_pages; 1168 } else { 1169 ret = pret < 0 ? pret : -EFAULT; 1170 } 1171 mmap_read_unlock(current->mm); 1172 if (ret) { 1173 /* 1174 * if we did partial map, or found file backed vmas, 1175 * release any pages we did get 1176 */ 1177 if (pret > 0) 1178 unpin_user_pages(pages, pret); 1179 goto done; 1180 } 1181 ret = 0; 1182 done: 1183 kvfree(vmas); 1184 if (ret < 0) { 1185 kvfree(pages); 1186 pages = ERR_PTR(ret); 1187 } 1188 return pages; 1189 } 1190 1191 static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov, 1192 struct io_mapped_ubuf **pimu, 1193 struct page **last_hpage) 1194 { 1195 struct io_mapped_ubuf *imu = NULL; 1196 struct page **pages = NULL; 1197 unsigned long off; 1198 size_t size; 1199 int ret, nr_pages, i; 1200 1201 *pimu = ctx->dummy_ubuf; 1202 if (!iov->iov_base) 1203 return 0; 1204 1205 ret = -ENOMEM; 1206 pages = io_pin_pages((unsigned long) iov->iov_base, iov->iov_len, 1207 &nr_pages); 1208 if (IS_ERR(pages)) { 1209 ret = PTR_ERR(pages); 1210 pages = NULL; 1211 goto done; 1212 } 1213 1214 imu = kvmalloc(struct_size(imu, bvec, nr_pages), GFP_KERNEL); 1215 if (!imu) 1216 goto done; 1217 1218 ret = io_buffer_account_pin(ctx, pages, nr_pages, imu, last_hpage); 1219 if (ret) { 1220 unpin_user_pages(pages, nr_pages); 1221 goto done; 1222 } 1223 1224 off = (unsigned long) iov->iov_base & ~PAGE_MASK; 1225 size = iov->iov_len; 1226 for (i = 0; i < nr_pages; i++) { 1227 size_t vec_len; 1228 1229 vec_len = min_t(size_t, size, PAGE_SIZE - off); 1230 imu->bvec[i].bv_page = pages[i]; 1231 imu->bvec[i].bv_len = vec_len; 1232 imu->bvec[i].bv_offset = off; 1233 off = 0; 1234 size -= vec_len; 1235 } 1236 /* store original address for later verification */ 1237 imu->ubuf = (unsigned long) iov->iov_base; 1238 imu->ubuf_end = imu->ubuf + iov->iov_len; 1239 imu->nr_bvecs = nr_pages; 1240 *pimu = imu; 1241 ret = 0; 1242 done: 1243 if (ret) 1244 kvfree(imu); 1245 kvfree(pages); 1246 return ret; 1247 } 1248 1249 static int io_buffers_map_alloc(struct io_ring_ctx *ctx, unsigned int nr_args) 1250 { 1251 ctx->user_bufs = kcalloc(nr_args, sizeof(*ctx->user_bufs), GFP_KERNEL); 1252 return ctx->user_bufs ? 0 : -ENOMEM; 1253 } 1254 1255 int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg, 1256 unsigned int nr_args, u64 __user *tags) 1257 { 1258 struct page *last_hpage = NULL; 1259 struct io_rsrc_data *data; 1260 int i, ret; 1261 struct iovec iov; 1262 1263 BUILD_BUG_ON(IORING_MAX_REG_BUFFERS >= (1u << 16)); 1264 1265 if (ctx->user_bufs) 1266 return -EBUSY; 1267 if (!nr_args || nr_args > IORING_MAX_REG_BUFFERS) 1268 return -EINVAL; 1269 ret = io_rsrc_node_switch_start(ctx); 1270 if (ret) 1271 return ret; 1272 ret = io_rsrc_data_alloc(ctx, io_rsrc_buf_put, tags, nr_args, &data); 1273 if (ret) 1274 return ret; 1275 ret = io_buffers_map_alloc(ctx, nr_args); 1276 if (ret) { 1277 io_rsrc_data_free(data); 1278 return ret; 1279 } 1280 1281 for (i = 0; i < nr_args; i++, ctx->nr_user_bufs++) { 1282 if (arg) { 1283 ret = io_copy_iov(ctx, &iov, arg, i); 1284 if (ret) 1285 break; 1286 ret = io_buffer_validate(&iov); 1287 if (ret) 1288 break; 1289 } else { 1290 memset(&iov, 0, sizeof(iov)); 1291 } 1292 1293 if (!iov.iov_base && *io_get_tag_slot(data, i)) { 1294 ret = -EINVAL; 1295 break; 1296 } 1297 1298 ret = io_sqe_buffer_register(ctx, &iov, &ctx->user_bufs[i], 1299 &last_hpage); 1300 if (ret) 1301 break; 1302 } 1303 1304 WARN_ON_ONCE(ctx->buf_data); 1305 1306 ctx->buf_data = data; 1307 if (ret) 1308 __io_sqe_buffers_unregister(ctx); 1309 else 1310 io_rsrc_node_switch(ctx, NULL); 1311 return ret; 1312 } 1313 1314 int io_import_fixed(int ddir, struct iov_iter *iter, 1315 struct io_mapped_ubuf *imu, 1316 u64 buf_addr, size_t len) 1317 { 1318 u64 buf_end; 1319 size_t offset; 1320 1321 if (WARN_ON_ONCE(!imu)) 1322 return -EFAULT; 1323 if (unlikely(check_add_overflow(buf_addr, (u64)len, &buf_end))) 1324 return -EFAULT; 1325 /* not inside the mapped region */ 1326 if (unlikely(buf_addr < imu->ubuf || buf_end > imu->ubuf_end)) 1327 return -EFAULT; 1328 1329 /* 1330 * May not be a start of buffer, set size appropriately 1331 * and advance us to the beginning. 1332 */ 1333 offset = buf_addr - imu->ubuf; 1334 iov_iter_bvec(iter, ddir, imu->bvec, imu->nr_bvecs, offset + len); 1335 1336 if (offset) { 1337 /* 1338 * Don't use iov_iter_advance() here, as it's really slow for 1339 * using the latter parts of a big fixed buffer - it iterates 1340 * over each segment manually. We can cheat a bit here, because 1341 * we know that: 1342 * 1343 * 1) it's a BVEC iter, we set it up 1344 * 2) all bvecs are PAGE_SIZE in size, except potentially the 1345 * first and last bvec 1346 * 1347 * So just find our index, and adjust the iterator afterwards. 1348 * If the offset is within the first bvec (or the whole first 1349 * bvec, just use iov_iter_advance(). This makes it easier 1350 * since we can just skip the first segment, which may not 1351 * be PAGE_SIZE aligned. 1352 */ 1353 const struct bio_vec *bvec = imu->bvec; 1354 1355 if (offset <= bvec->bv_len) { 1356 iov_iter_advance(iter, offset); 1357 } else { 1358 unsigned long seg_skip; 1359 1360 /* skip first vec */ 1361 offset -= bvec->bv_len; 1362 seg_skip = 1 + (offset >> PAGE_SHIFT); 1363 1364 iter->bvec = bvec + seg_skip; 1365 iter->nr_segs -= seg_skip; 1366 iter->count -= bvec->bv_len + offset; 1367 iter->iov_offset = offset & ~PAGE_MASK; 1368 } 1369 } 1370 1371 return 0; 1372 } 1373