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 int __io_account_mem(struct user_struct *user, unsigned long nr_pages) 35 { 36 unsigned long page_limit, cur_pages, new_pages; 37 38 if (!nr_pages) 39 return 0; 40 41 /* Don't allow more pages than we can safely lock */ 42 page_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; 43 44 cur_pages = atomic_long_read(&user->locked_vm); 45 do { 46 new_pages = cur_pages + nr_pages; 47 if (new_pages > page_limit) 48 return -ENOMEM; 49 } while (!atomic_long_try_cmpxchg(&user->locked_vm, 50 &cur_pages, new_pages)); 51 return 0; 52 } 53 54 static void io_unaccount_mem(struct io_ring_ctx *ctx, unsigned long nr_pages) 55 { 56 if (ctx->user) 57 __io_unaccount_mem(ctx->user, nr_pages); 58 59 if (ctx->mm_account) 60 atomic64_sub(nr_pages, &ctx->mm_account->pinned_vm); 61 } 62 63 static int io_account_mem(struct io_ring_ctx *ctx, unsigned long nr_pages) 64 { 65 int ret; 66 67 if (ctx->user) { 68 ret = __io_account_mem(ctx->user, nr_pages); 69 if (ret) 70 return ret; 71 } 72 73 if (ctx->mm_account) 74 atomic64_add(nr_pages, &ctx->mm_account->pinned_vm); 75 76 return 0; 77 } 78 79 static int io_copy_iov(struct io_ring_ctx *ctx, struct iovec *dst, 80 void __user *arg, unsigned index) 81 { 82 struct iovec __user *src; 83 84 #ifdef CONFIG_COMPAT 85 if (ctx->compat) { 86 struct compat_iovec __user *ciovs; 87 struct compat_iovec ciov; 88 89 ciovs = (struct compat_iovec __user *) arg; 90 if (copy_from_user(&ciov, &ciovs[index], sizeof(ciov))) 91 return -EFAULT; 92 93 dst->iov_base = u64_to_user_ptr((u64)ciov.iov_base); 94 dst->iov_len = ciov.iov_len; 95 return 0; 96 } 97 #endif 98 src = (struct iovec __user *) arg; 99 if (copy_from_user(dst, &src[index], sizeof(*dst))) 100 return -EFAULT; 101 return 0; 102 } 103 104 static int io_buffer_validate(struct iovec *iov) 105 { 106 unsigned long tmp, acct_len = iov->iov_len + (PAGE_SIZE - 1); 107 108 /* 109 * Don't impose further limits on the size and buffer 110 * constraints here, we'll -EINVAL later when IO is 111 * submitted if they are wrong. 112 */ 113 if (!iov->iov_base) 114 return iov->iov_len ? -EFAULT : 0; 115 if (!iov->iov_len) 116 return -EFAULT; 117 118 /* arbitrary limit, but we need something */ 119 if (iov->iov_len > SZ_1G) 120 return -EFAULT; 121 122 if (check_add_overflow((unsigned long)iov->iov_base, acct_len, &tmp)) 123 return -EOVERFLOW; 124 125 return 0; 126 } 127 128 static void io_buffer_unmap(struct io_ring_ctx *ctx, struct io_mapped_ubuf **slot) 129 { 130 struct io_mapped_ubuf *imu = *slot; 131 unsigned int i; 132 133 if (imu != ctx->dummy_ubuf) { 134 for (i = 0; i < imu->nr_bvecs; i++) 135 unpin_user_page(imu->bvec[i].bv_page); 136 if (imu->acct_pages) 137 io_unaccount_mem(ctx, imu->acct_pages); 138 kvfree(imu); 139 } 140 *slot = NULL; 141 } 142 143 static void io_rsrc_put_work_one(struct io_rsrc_data *rsrc_data, 144 struct io_rsrc_put *prsrc) 145 { 146 struct io_ring_ctx *ctx = rsrc_data->ctx; 147 148 if (prsrc->tag) 149 io_post_aux_cqe(ctx, prsrc->tag, 0, 0); 150 rsrc_data->do_put(ctx, prsrc); 151 } 152 153 static void __io_rsrc_put_work(struct io_rsrc_node *ref_node) 154 { 155 struct io_rsrc_data *rsrc_data = ref_node->rsrc_data; 156 struct io_rsrc_put *prsrc, *tmp; 157 158 if (ref_node->inline_items) 159 io_rsrc_put_work_one(rsrc_data, &ref_node->item); 160 161 list_for_each_entry_safe(prsrc, tmp, &ref_node->item_list, list) { 162 list_del(&prsrc->list); 163 io_rsrc_put_work_one(rsrc_data, prsrc); 164 kfree(prsrc); 165 } 166 167 io_rsrc_node_destroy(ref_node); 168 if (atomic_dec_and_test(&rsrc_data->refs)) 169 complete(&rsrc_data->done); 170 } 171 172 void io_wait_rsrc_data(struct io_rsrc_data *data) 173 { 174 if (data && !atomic_dec_and_test(&data->refs)) 175 wait_for_completion(&data->done); 176 } 177 178 void io_rsrc_node_destroy(struct io_rsrc_node *ref_node) 179 { 180 kfree(ref_node); 181 } 182 183 void io_rsrc_node_ref_zero(struct io_rsrc_node *node) 184 __must_hold(&node->rsrc_data->ctx->uring_lock) 185 { 186 struct io_ring_ctx *ctx = node->rsrc_data->ctx; 187 188 node->done = true; 189 while (!list_empty(&ctx->rsrc_ref_list)) { 190 node = list_first_entry(&ctx->rsrc_ref_list, 191 struct io_rsrc_node, node); 192 /* recycle ref nodes in order */ 193 if (!node->done) 194 break; 195 196 list_del(&node->node); 197 __io_rsrc_put_work(node); 198 } 199 } 200 201 static struct io_rsrc_node *io_rsrc_node_alloc(void) 202 { 203 struct io_rsrc_node *ref_node; 204 205 ref_node = kzalloc(sizeof(*ref_node), GFP_KERNEL); 206 if (!ref_node) 207 return NULL; 208 209 ref_node->refs = 1; 210 INIT_LIST_HEAD(&ref_node->node); 211 INIT_LIST_HEAD(&ref_node->item_list); 212 ref_node->done = false; 213 ref_node->inline_items = 0; 214 return ref_node; 215 } 216 217 void io_rsrc_node_switch(struct io_ring_ctx *ctx, 218 struct io_rsrc_data *data_to_kill) 219 __must_hold(&ctx->uring_lock) 220 { 221 WARN_ON_ONCE(!ctx->rsrc_backup_node); 222 WARN_ON_ONCE(data_to_kill && !ctx->rsrc_node); 223 224 if (data_to_kill) { 225 struct io_rsrc_node *rsrc_node = ctx->rsrc_node; 226 227 rsrc_node->rsrc_data = data_to_kill; 228 list_add_tail(&rsrc_node->node, &ctx->rsrc_ref_list); 229 230 atomic_inc(&data_to_kill->refs); 231 /* put master ref */ 232 io_put_rsrc_node(rsrc_node); 233 ctx->rsrc_node = NULL; 234 } 235 236 if (!ctx->rsrc_node) { 237 ctx->rsrc_node = ctx->rsrc_backup_node; 238 ctx->rsrc_backup_node = NULL; 239 } 240 } 241 242 int io_rsrc_node_switch_start(struct io_ring_ctx *ctx) 243 { 244 if (ctx->rsrc_backup_node) 245 return 0; 246 ctx->rsrc_backup_node = io_rsrc_node_alloc(); 247 return ctx->rsrc_backup_node ? 0 : -ENOMEM; 248 } 249 250 __cold static int io_rsrc_ref_quiesce(struct io_rsrc_data *data, 251 struct io_ring_ctx *ctx) 252 { 253 int ret; 254 255 /* As we may drop ->uring_lock, other task may have started quiesce */ 256 if (data->quiesce) 257 return -ENXIO; 258 ret = io_rsrc_node_switch_start(ctx); 259 if (ret) 260 return ret; 261 io_rsrc_node_switch(ctx, data); 262 263 /* kill initial ref, already quiesced if zero */ 264 if (atomic_dec_and_test(&data->refs)) 265 return 0; 266 267 data->quiesce = true; 268 mutex_unlock(&ctx->uring_lock); 269 do { 270 ret = io_run_task_work_sig(ctx); 271 if (ret < 0) { 272 atomic_inc(&data->refs); 273 /* wait for all works potentially completing data->done */ 274 reinit_completion(&data->done); 275 mutex_lock(&ctx->uring_lock); 276 break; 277 } 278 279 ret = wait_for_completion_interruptible(&data->done); 280 if (!ret) { 281 mutex_lock(&ctx->uring_lock); 282 if (atomic_read(&data->refs) <= 0) 283 break; 284 /* 285 * it has been revived by another thread while 286 * we were unlocked 287 */ 288 mutex_unlock(&ctx->uring_lock); 289 } 290 } while (1); 291 data->quiesce = false; 292 293 return ret; 294 } 295 296 static void io_free_page_table(void **table, size_t size) 297 { 298 unsigned i, nr_tables = DIV_ROUND_UP(size, PAGE_SIZE); 299 300 for (i = 0; i < nr_tables; i++) 301 kfree(table[i]); 302 kfree(table); 303 } 304 305 static void io_rsrc_data_free(struct io_rsrc_data *data) 306 { 307 size_t size = data->nr * sizeof(data->tags[0][0]); 308 309 if (data->tags) 310 io_free_page_table((void **)data->tags, size); 311 kfree(data); 312 } 313 314 static __cold void **io_alloc_page_table(size_t size) 315 { 316 unsigned i, nr_tables = DIV_ROUND_UP(size, PAGE_SIZE); 317 size_t init_size = size; 318 void **table; 319 320 table = kcalloc(nr_tables, sizeof(*table), GFP_KERNEL_ACCOUNT); 321 if (!table) 322 return NULL; 323 324 for (i = 0; i < nr_tables; i++) { 325 unsigned int this_size = min_t(size_t, size, PAGE_SIZE); 326 327 table[i] = kzalloc(this_size, GFP_KERNEL_ACCOUNT); 328 if (!table[i]) { 329 io_free_page_table(table, init_size); 330 return NULL; 331 } 332 size -= this_size; 333 } 334 return table; 335 } 336 337 __cold static int io_rsrc_data_alloc(struct io_ring_ctx *ctx, 338 rsrc_put_fn *do_put, u64 __user *utags, 339 unsigned nr, struct io_rsrc_data **pdata) 340 { 341 struct io_rsrc_data *data; 342 int ret = 0; 343 unsigned i; 344 345 data = kzalloc(sizeof(*data), GFP_KERNEL); 346 if (!data) 347 return -ENOMEM; 348 data->tags = (u64 **)io_alloc_page_table(nr * sizeof(data->tags[0][0])); 349 if (!data->tags) { 350 kfree(data); 351 return -ENOMEM; 352 } 353 354 data->nr = nr; 355 data->ctx = ctx; 356 data->do_put = do_put; 357 if (utags) { 358 ret = -EFAULT; 359 for (i = 0; i < nr; i++) { 360 u64 *tag_slot = io_get_tag_slot(data, i); 361 362 if (copy_from_user(tag_slot, &utags[i], 363 sizeof(*tag_slot))) 364 goto fail; 365 } 366 } 367 368 atomic_set(&data->refs, 1); 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, offset) = 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 if (check_add_overflow(up->offset, nr_args, &tmp)) 525 return -EOVERFLOW; 526 err = io_rsrc_node_switch_start(ctx); 527 if (err) 528 return err; 529 530 switch (type) { 531 case IORING_RSRC_FILE: 532 return __io_sqe_files_update(ctx, up, nr_args); 533 case IORING_RSRC_BUFFER: 534 return __io_sqe_buffers_update(ctx, up, nr_args); 535 } 536 return -EINVAL; 537 } 538 539 int io_register_files_update(struct io_ring_ctx *ctx, void __user *arg, 540 unsigned nr_args) 541 { 542 struct io_uring_rsrc_update2 up; 543 544 if (!nr_args) 545 return -EINVAL; 546 memset(&up, 0, sizeof(up)); 547 if (copy_from_user(&up, arg, sizeof(struct io_uring_rsrc_update))) 548 return -EFAULT; 549 if (up.resv || up.resv2) 550 return -EINVAL; 551 return __io_register_rsrc_update(ctx, IORING_RSRC_FILE, &up, nr_args); 552 } 553 554 int io_register_rsrc_update(struct io_ring_ctx *ctx, void __user *arg, 555 unsigned size, unsigned type) 556 { 557 struct io_uring_rsrc_update2 up; 558 559 if (size != sizeof(up)) 560 return -EINVAL; 561 if (copy_from_user(&up, arg, sizeof(up))) 562 return -EFAULT; 563 if (!up.nr || up.resv || up.resv2) 564 return -EINVAL; 565 return __io_register_rsrc_update(ctx, type, &up, up.nr); 566 } 567 568 __cold int io_register_rsrc(struct io_ring_ctx *ctx, void __user *arg, 569 unsigned int size, unsigned int type) 570 { 571 struct io_uring_rsrc_register rr; 572 573 /* keep it extendible */ 574 if (size != sizeof(rr)) 575 return -EINVAL; 576 577 memset(&rr, 0, sizeof(rr)); 578 if (copy_from_user(&rr, arg, size)) 579 return -EFAULT; 580 if (!rr.nr || rr.resv2) 581 return -EINVAL; 582 if (rr.flags & ~IORING_RSRC_REGISTER_SPARSE) 583 return -EINVAL; 584 585 switch (type) { 586 case IORING_RSRC_FILE: 587 if (rr.flags & IORING_RSRC_REGISTER_SPARSE && rr.data) 588 break; 589 return io_sqe_files_register(ctx, u64_to_user_ptr(rr.data), 590 rr.nr, u64_to_user_ptr(rr.tags)); 591 case IORING_RSRC_BUFFER: 592 if (rr.flags & IORING_RSRC_REGISTER_SPARSE && rr.data) 593 break; 594 return io_sqe_buffers_register(ctx, u64_to_user_ptr(rr.data), 595 rr.nr, u64_to_user_ptr(rr.tags)); 596 } 597 return -EINVAL; 598 } 599 600 int io_files_update_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) 601 { 602 struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update); 603 604 if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT))) 605 return -EINVAL; 606 if (sqe->rw_flags || sqe->splice_fd_in) 607 return -EINVAL; 608 609 up->offset = READ_ONCE(sqe->off); 610 up->nr_args = READ_ONCE(sqe->len); 611 if (!up->nr_args) 612 return -EINVAL; 613 up->arg = READ_ONCE(sqe->addr); 614 return 0; 615 } 616 617 static int io_files_update_with_index_alloc(struct io_kiocb *req, 618 unsigned int issue_flags) 619 { 620 struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update); 621 __s32 __user *fds = u64_to_user_ptr(up->arg); 622 unsigned int done; 623 struct file *file; 624 int ret, fd; 625 626 if (!req->ctx->file_data) 627 return -ENXIO; 628 629 for (done = 0; done < up->nr_args; done++) { 630 if (copy_from_user(&fd, &fds[done], sizeof(fd))) { 631 ret = -EFAULT; 632 break; 633 } 634 635 file = fget(fd); 636 if (!file) { 637 ret = -EBADF; 638 break; 639 } 640 ret = io_fixed_fd_install(req, issue_flags, file, 641 IORING_FILE_INDEX_ALLOC); 642 if (ret < 0) 643 break; 644 if (copy_to_user(&fds[done], &ret, sizeof(ret))) { 645 __io_close_fixed(req->ctx, issue_flags, ret); 646 ret = -EFAULT; 647 break; 648 } 649 } 650 651 if (done) 652 return done; 653 return ret; 654 } 655 656 int io_files_update(struct io_kiocb *req, unsigned int issue_flags) 657 { 658 struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update); 659 struct io_ring_ctx *ctx = req->ctx; 660 struct io_uring_rsrc_update2 up2; 661 int ret; 662 663 up2.offset = up->offset; 664 up2.data = up->arg; 665 up2.nr = 0; 666 up2.tags = 0; 667 up2.resv = 0; 668 up2.resv2 = 0; 669 670 if (up->offset == IORING_FILE_INDEX_ALLOC) { 671 ret = io_files_update_with_index_alloc(req, issue_flags); 672 } else { 673 io_ring_submit_lock(ctx, issue_flags); 674 ret = __io_register_rsrc_update(ctx, IORING_RSRC_FILE, 675 &up2, up->nr_args); 676 io_ring_submit_unlock(ctx, issue_flags); 677 } 678 679 if (ret < 0) 680 req_set_fail(req); 681 io_req_set_res(req, ret, 0); 682 return IOU_OK; 683 } 684 685 int io_queue_rsrc_removal(struct io_rsrc_data *data, unsigned idx, 686 struct io_rsrc_node *node, void *rsrc) 687 { 688 u64 *tag_slot = io_get_tag_slot(data, idx); 689 struct io_rsrc_put *prsrc; 690 bool inline_item = true; 691 692 if (!node->inline_items) { 693 prsrc = &node->item; 694 node->inline_items++; 695 } else { 696 prsrc = kzalloc(sizeof(*prsrc), GFP_KERNEL); 697 if (!prsrc) 698 return -ENOMEM; 699 inline_item = false; 700 } 701 702 prsrc->tag = *tag_slot; 703 *tag_slot = 0; 704 prsrc->rsrc = rsrc; 705 if (!inline_item) 706 list_add(&prsrc->list, &node->item_list); 707 return 0; 708 } 709 710 void __io_sqe_files_unregister(struct io_ring_ctx *ctx) 711 { 712 int i; 713 714 for (i = 0; i < ctx->nr_user_files; i++) { 715 struct file *file = io_file_from_index(&ctx->file_table, i); 716 717 /* skip scm accounted files, they'll be freed by ->ring_sock */ 718 if (!file || io_file_need_scm(file)) 719 continue; 720 io_file_bitmap_clear(&ctx->file_table, i); 721 fput(file); 722 } 723 724 #if defined(CONFIG_UNIX) 725 if (ctx->ring_sock) { 726 struct sock *sock = ctx->ring_sock->sk; 727 struct sk_buff *skb; 728 729 while ((skb = skb_dequeue(&sock->sk_receive_queue)) != NULL) 730 kfree_skb(skb); 731 } 732 #endif 733 io_free_file_tables(&ctx->file_table); 734 io_file_table_set_alloc_range(ctx, 0, 0); 735 io_rsrc_data_free(ctx->file_data); 736 ctx->file_data = NULL; 737 ctx->nr_user_files = 0; 738 } 739 740 int io_sqe_files_unregister(struct io_ring_ctx *ctx) 741 { 742 unsigned nr = ctx->nr_user_files; 743 int ret; 744 745 if (!ctx->file_data) 746 return -ENXIO; 747 748 /* 749 * Quiesce may unlock ->uring_lock, and while it's not held 750 * prevent new requests using the table. 751 */ 752 ctx->nr_user_files = 0; 753 ret = io_rsrc_ref_quiesce(ctx->file_data, ctx); 754 ctx->nr_user_files = nr; 755 if (!ret) 756 __io_sqe_files_unregister(ctx); 757 return ret; 758 } 759 760 /* 761 * Ensure the UNIX gc is aware of our file set, so we are certain that 762 * the io_uring can be safely unregistered on process exit, even if we have 763 * loops in the file referencing. We account only files that can hold other 764 * files because otherwise they can't form a loop and so are not interesting 765 * for GC. 766 */ 767 int __io_scm_file_account(struct io_ring_ctx *ctx, struct file *file) 768 { 769 #if defined(CONFIG_UNIX) 770 struct sock *sk = ctx->ring_sock->sk; 771 struct sk_buff_head *head = &sk->sk_receive_queue; 772 struct scm_fp_list *fpl; 773 struct sk_buff *skb; 774 775 if (likely(!io_file_need_scm(file))) 776 return 0; 777 778 /* 779 * See if we can merge this file into an existing skb SCM_RIGHTS 780 * file set. If there's no room, fall back to allocating a new skb 781 * and filling it in. 782 */ 783 spin_lock_irq(&head->lock); 784 skb = skb_peek(head); 785 if (skb && UNIXCB(skb).fp->count < SCM_MAX_FD) 786 __skb_unlink(skb, head); 787 else 788 skb = NULL; 789 spin_unlock_irq(&head->lock); 790 791 if (!skb) { 792 fpl = kzalloc(sizeof(*fpl), GFP_KERNEL); 793 if (!fpl) 794 return -ENOMEM; 795 796 skb = alloc_skb(0, GFP_KERNEL); 797 if (!skb) { 798 kfree(fpl); 799 return -ENOMEM; 800 } 801 802 fpl->user = get_uid(current_user()); 803 fpl->max = SCM_MAX_FD; 804 fpl->count = 0; 805 806 UNIXCB(skb).fp = fpl; 807 skb->sk = sk; 808 skb->scm_io_uring = 1; 809 skb->destructor = unix_destruct_scm; 810 refcount_add(skb->truesize, &sk->sk_wmem_alloc); 811 } 812 813 fpl = UNIXCB(skb).fp; 814 fpl->fp[fpl->count++] = get_file(file); 815 unix_inflight(fpl->user, file); 816 skb_queue_head(head, skb); 817 fput(file); 818 #endif 819 return 0; 820 } 821 822 static void io_rsrc_file_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc) 823 { 824 struct file *file = prsrc->file; 825 #if defined(CONFIG_UNIX) 826 struct sock *sock = ctx->ring_sock->sk; 827 struct sk_buff_head list, *head = &sock->sk_receive_queue; 828 struct sk_buff *skb; 829 int i; 830 831 if (!io_file_need_scm(file)) { 832 fput(file); 833 return; 834 } 835 836 __skb_queue_head_init(&list); 837 838 /* 839 * Find the skb that holds this file in its SCM_RIGHTS. When found, 840 * remove this entry and rearrange the file array. 841 */ 842 skb = skb_dequeue(head); 843 while (skb) { 844 struct scm_fp_list *fp; 845 846 fp = UNIXCB(skb).fp; 847 for (i = 0; i < fp->count; i++) { 848 int left; 849 850 if (fp->fp[i] != file) 851 continue; 852 853 unix_notinflight(fp->user, fp->fp[i]); 854 left = fp->count - 1 - i; 855 if (left) { 856 memmove(&fp->fp[i], &fp->fp[i + 1], 857 left * sizeof(struct file *)); 858 } 859 fp->count--; 860 if (!fp->count) { 861 kfree_skb(skb); 862 skb = NULL; 863 } else { 864 __skb_queue_tail(&list, skb); 865 } 866 fput(file); 867 file = NULL; 868 break; 869 } 870 871 if (!file) 872 break; 873 874 __skb_queue_tail(&list, skb); 875 876 skb = skb_dequeue(head); 877 } 878 879 if (skb_peek(&list)) { 880 spin_lock_irq(&head->lock); 881 while ((skb = __skb_dequeue(&list)) != NULL) 882 __skb_queue_tail(head, skb); 883 spin_unlock_irq(&head->lock); 884 } 885 #else 886 fput(file); 887 #endif 888 } 889 890 int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg, 891 unsigned nr_args, u64 __user *tags) 892 { 893 __s32 __user *fds = (__s32 __user *) arg; 894 struct file *file; 895 int fd, ret; 896 unsigned i; 897 898 if (ctx->file_data) 899 return -EBUSY; 900 if (!nr_args) 901 return -EINVAL; 902 if (nr_args > IORING_MAX_FIXED_FILES) 903 return -EMFILE; 904 if (nr_args > rlimit(RLIMIT_NOFILE)) 905 return -EMFILE; 906 ret = io_rsrc_node_switch_start(ctx); 907 if (ret) 908 return ret; 909 ret = io_rsrc_data_alloc(ctx, io_rsrc_file_put, tags, nr_args, 910 &ctx->file_data); 911 if (ret) 912 return ret; 913 914 if (!io_alloc_file_tables(&ctx->file_table, nr_args)) { 915 io_rsrc_data_free(ctx->file_data); 916 ctx->file_data = NULL; 917 return -ENOMEM; 918 } 919 920 for (i = 0; i < nr_args; i++, ctx->nr_user_files++) { 921 struct io_fixed_file *file_slot; 922 923 if (fds && copy_from_user(&fd, &fds[i], sizeof(fd))) { 924 ret = -EFAULT; 925 goto fail; 926 } 927 /* allow sparse sets */ 928 if (!fds || fd == -1) { 929 ret = -EINVAL; 930 if (unlikely(*io_get_tag_slot(ctx->file_data, i))) 931 goto fail; 932 continue; 933 } 934 935 file = fget(fd); 936 ret = -EBADF; 937 if (unlikely(!file)) 938 goto fail; 939 940 /* 941 * Don't allow io_uring instances to be registered. If UNIX 942 * isn't enabled, then this causes a reference cycle and this 943 * instance can never get freed. If UNIX is enabled we'll 944 * handle it just fine, but there's still no point in allowing 945 * a ring fd as it doesn't support regular read/write anyway. 946 */ 947 if (io_is_uring_fops(file)) { 948 fput(file); 949 goto fail; 950 } 951 ret = io_scm_file_account(ctx, file); 952 if (ret) { 953 fput(file); 954 goto fail; 955 } 956 file_slot = io_fixed_file_slot(&ctx->file_table, i); 957 io_fixed_file_set(file_slot, file); 958 io_file_bitmap_set(&ctx->file_table, i); 959 } 960 961 /* default it to the whole table */ 962 io_file_table_set_alloc_range(ctx, 0, ctx->nr_user_files); 963 io_rsrc_node_switch(ctx, NULL); 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_node_switch_start(ctx); 1246 if (ret) 1247 return ret; 1248 ret = io_rsrc_data_alloc(ctx, io_rsrc_buf_put, tags, nr_args, &data); 1249 if (ret) 1250 return ret; 1251 ret = io_buffers_map_alloc(ctx, nr_args); 1252 if (ret) { 1253 io_rsrc_data_free(data); 1254 return ret; 1255 } 1256 1257 for (i = 0; i < nr_args; i++, ctx->nr_user_bufs++) { 1258 if (arg) { 1259 ret = io_copy_iov(ctx, &iov, arg, i); 1260 if (ret) 1261 break; 1262 ret = io_buffer_validate(&iov); 1263 if (ret) 1264 break; 1265 } else { 1266 memset(&iov, 0, sizeof(iov)); 1267 } 1268 1269 if (!iov.iov_base && *io_get_tag_slot(data, i)) { 1270 ret = -EINVAL; 1271 break; 1272 } 1273 1274 ret = io_sqe_buffer_register(ctx, &iov, &ctx->user_bufs[i], 1275 &last_hpage); 1276 if (ret) 1277 break; 1278 } 1279 1280 WARN_ON_ONCE(ctx->buf_data); 1281 1282 ctx->buf_data = data; 1283 if (ret) 1284 __io_sqe_buffers_unregister(ctx); 1285 else 1286 io_rsrc_node_switch(ctx, NULL); 1287 return ret; 1288 } 1289 1290 int io_import_fixed(int ddir, struct iov_iter *iter, 1291 struct io_mapped_ubuf *imu, 1292 u64 buf_addr, size_t len) 1293 { 1294 u64 buf_end; 1295 size_t offset; 1296 1297 if (WARN_ON_ONCE(!imu)) 1298 return -EFAULT; 1299 if (unlikely(check_add_overflow(buf_addr, (u64)len, &buf_end))) 1300 return -EFAULT; 1301 /* not inside the mapped region */ 1302 if (unlikely(buf_addr < imu->ubuf || buf_end > imu->ubuf_end)) 1303 return -EFAULT; 1304 1305 /* 1306 * Might not be a start of buffer, set size appropriately 1307 * and advance us to the beginning. 1308 */ 1309 offset = buf_addr - imu->ubuf; 1310 iov_iter_bvec(iter, ddir, imu->bvec, imu->nr_bvecs, offset + len); 1311 1312 if (offset) { 1313 /* 1314 * Don't use iov_iter_advance() here, as it's really slow for 1315 * using the latter parts of a big fixed buffer - it iterates 1316 * over each segment manually. We can cheat a bit here, because 1317 * we know that: 1318 * 1319 * 1) it's a BVEC iter, we set it up 1320 * 2) all bvecs are PAGE_SIZE in size, except potentially the 1321 * first and last bvec 1322 * 1323 * So just find our index, and adjust the iterator afterwards. 1324 * If the offset is within the first bvec (or the whole first 1325 * bvec, just use iov_iter_advance(). This makes it easier 1326 * since we can just skip the first segment, which may not 1327 * be PAGE_SIZE aligned. 1328 */ 1329 const struct bio_vec *bvec = imu->bvec; 1330 1331 if (offset <= bvec->bv_len) { 1332 /* 1333 * Note, huge pages buffers consists of one large 1334 * bvec entry and should always go this way. The other 1335 * branch doesn't expect non PAGE_SIZE'd chunks. 1336 */ 1337 iter->bvec = bvec; 1338 iter->nr_segs = bvec->bv_len; 1339 iter->count -= offset; 1340 iter->iov_offset = offset; 1341 } else { 1342 unsigned long seg_skip; 1343 1344 /* skip first vec */ 1345 offset -= bvec->bv_len; 1346 seg_skip = 1 + (offset >> PAGE_SHIFT); 1347 1348 iter->bvec = bvec + seg_skip; 1349 iter->nr_segs -= seg_skip; 1350 iter->count -= bvec->bv_len + offset; 1351 iter->iov_offset = offset & ~PAGE_MASK; 1352 } 1353 } 1354 1355 return 0; 1356 } 1357