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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#include "memmap.h"
19#include "register.h"
20
21struct io_rsrc_update {
22 struct file *file;
23 u64 arg;
24 u32 nr_args;
25 u32 offset;
26};
27
28static struct io_rsrc_node *io_sqe_buffer_register(struct io_ring_ctx *ctx,
29 struct iovec *iov, struct page **last_hpage);
30
31/* only define max */
32#define IORING_MAX_FIXED_FILES (1U << 20)
33#define IORING_MAX_REG_BUFFERS (1U << 14)
34
35int __io_account_mem(struct user_struct *user, unsigned long nr_pages)
36{
37 unsigned long page_limit, cur_pages, new_pages;
38
39 if (!nr_pages)
40 return 0;
41
42 /* Don't allow more pages than we can safely lock */
43 page_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
44
45 cur_pages = atomic_long_read(&user->locked_vm);
46 do {
47 new_pages = cur_pages + nr_pages;
48 if (new_pages > page_limit)
49 return -ENOMEM;
50 } while (!atomic_long_try_cmpxchg(&user->locked_vm,
51 &cur_pages, new_pages));
52 return 0;
53}
54
55static void io_unaccount_mem(struct io_ring_ctx *ctx, unsigned long nr_pages)
56{
57 if (ctx->user)
58 __io_unaccount_mem(ctx->user, nr_pages);
59
60 if (ctx->mm_account)
61 atomic64_sub(nr_pages, &ctx->mm_account->pinned_vm);
62}
63
64static int io_account_mem(struct io_ring_ctx *ctx, unsigned long nr_pages)
65{
66 int ret;
67
68 if (ctx->user) {
69 ret = __io_account_mem(ctx->user, nr_pages);
70 if (ret)
71 return ret;
72 }
73
74 if (ctx->mm_account)
75 atomic64_add(nr_pages, &ctx->mm_account->pinned_vm);
76
77 return 0;
78}
79
80static int io_buffer_validate(struct iovec *iov)
81{
82 unsigned long tmp, acct_len = iov->iov_len + (PAGE_SIZE - 1);
83
84 /*
85 * Don't impose further limits on the size and buffer
86 * constraints here, we'll -EINVAL later when IO is
87 * submitted if they are wrong.
88 */
89 if (!iov->iov_base)
90 return iov->iov_len ? -EFAULT : 0;
91 if (!iov->iov_len)
92 return -EFAULT;
93
94 /* arbitrary limit, but we need something */
95 if (iov->iov_len > SZ_1G)
96 return -EFAULT;
97
98 if (check_add_overflow((unsigned long)iov->iov_base, acct_len, &tmp))
99 return -EOVERFLOW;
100
101 return 0;
102}
103
104static void io_buffer_unmap(struct io_ring_ctx *ctx, struct io_rsrc_node *node)
105{
106 unsigned int i;
107
108 if (node->buf) {
109 struct io_mapped_ubuf *imu = node->buf;
110
111 if (!refcount_dec_and_test(&imu->refs))
112 return;
113 for (i = 0; i < imu->nr_bvecs; i++)
114 unpin_user_page(imu->bvec[i].bv_page);
115 if (imu->acct_pages)
116 io_unaccount_mem(ctx, imu->acct_pages);
117 kvfree(imu);
118 }
119}
120
121struct io_rsrc_node *io_rsrc_node_alloc(struct io_ring_ctx *ctx, int type)
122{
123 struct io_rsrc_node *node;
124
125 node = kzalloc(sizeof(*node), GFP_KERNEL);
126 if (node) {
127 node->type = type;
128 node->refs = 1;
129 }
130 return node;
131}
132
133__cold void io_rsrc_data_free(struct io_ring_ctx *ctx, struct io_rsrc_data *data)
134{
135 if (!data->nr)
136 return;
137 while (data->nr--) {
138 if (data->nodes[data->nr])
139 io_put_rsrc_node(ctx, data->nodes[data->nr]);
140 }
141 kvfree(data->nodes);
142 data->nodes = NULL;
143 data->nr = 0;
144}
145
146__cold int io_rsrc_data_alloc(struct io_rsrc_data *data, unsigned nr)
147{
148 data->nodes = kvmalloc_array(nr, sizeof(struct io_rsrc_node *),
149 GFP_KERNEL_ACCOUNT | __GFP_ZERO);
150 if (data->nodes) {
151 data->nr = nr;
152 return 0;
153 }
154 return -ENOMEM;
155}
156
157static int __io_sqe_files_update(struct io_ring_ctx *ctx,
158 struct io_uring_rsrc_update2 *up,
159 unsigned nr_args)
160{
161 u64 __user *tags = u64_to_user_ptr(up->tags);
162 __s32 __user *fds = u64_to_user_ptr(up->data);
163 int fd, i, err = 0;
164 unsigned int done;
165
166 if (!ctx->file_table.data.nr)
167 return -ENXIO;
168 if (up->offset + nr_args > ctx->file_table.data.nr)
169 return -EINVAL;
170
171 for (done = 0; done < nr_args; done++) {
172 u64 tag = 0;
173
174 if ((tags && copy_from_user(&tag, &tags[done], sizeof(tag))) ||
175 copy_from_user(&fd, &fds[done], sizeof(fd))) {
176 err = -EFAULT;
177 break;
178 }
179 if ((fd == IORING_REGISTER_FILES_SKIP || fd == -1) && tag) {
180 err = -EINVAL;
181 break;
182 }
183 if (fd == IORING_REGISTER_FILES_SKIP)
184 continue;
185
186 i = up->offset + done;
187 if (io_reset_rsrc_node(ctx, &ctx->file_table.data, i))
188 io_file_bitmap_clear(&ctx->file_table, i);
189
190 if (fd != -1) {
191 struct file *file = fget(fd);
192 struct io_rsrc_node *node;
193
194 if (!file) {
195 err = -EBADF;
196 break;
197 }
198 /*
199 * Don't allow io_uring instances to be registered.
200 */
201 if (io_is_uring_fops(file)) {
202 fput(file);
203 err = -EBADF;
204 break;
205 }
206 node = io_rsrc_node_alloc(ctx, IORING_RSRC_FILE);
207 if (!node) {
208 err = -ENOMEM;
209 fput(file);
210 break;
211 }
212 ctx->file_table.data.nodes[i] = node;
213 if (tag)
214 node->tag = tag;
215 io_fixed_file_set(node, file);
216 io_file_bitmap_set(&ctx->file_table, i);
217 }
218 }
219 return done ? done : err;
220}
221
222static int __io_sqe_buffers_update(struct io_ring_ctx *ctx,
223 struct io_uring_rsrc_update2 *up,
224 unsigned int nr_args)
225{
226 u64 __user *tags = u64_to_user_ptr(up->tags);
227 struct iovec fast_iov, *iov;
228 struct page *last_hpage = NULL;
229 struct iovec __user *uvec;
230 u64 user_data = up->data;
231 __u32 done;
232 int i, err;
233
234 if (!ctx->buf_table.nr)
235 return -ENXIO;
236 if (up->offset + nr_args > ctx->buf_table.nr)
237 return -EINVAL;
238
239 for (done = 0; done < nr_args; done++) {
240 struct io_rsrc_node *node;
241 u64 tag = 0;
242
243 uvec = u64_to_user_ptr(user_data);
244 iov = iovec_from_user(uvec, 1, 1, &fast_iov, ctx->compat);
245 if (IS_ERR(iov)) {
246 err = PTR_ERR(iov);
247 break;
248 }
249 if (tags && copy_from_user(&tag, &tags[done], sizeof(tag))) {
250 err = -EFAULT;
251 break;
252 }
253 err = io_buffer_validate(iov);
254 if (err)
255 break;
256 node = io_sqe_buffer_register(ctx, iov, &last_hpage);
257 if (IS_ERR(node)) {
258 err = PTR_ERR(node);
259 break;
260 }
261 if (tag) {
262 if (!node) {
263 err = -EINVAL;
264 break;
265 }
266 node->tag = tag;
267 }
268 i = array_index_nospec(up->offset + done, ctx->buf_table.nr);
269 io_reset_rsrc_node(ctx, &ctx->buf_table, i);
270 ctx->buf_table.nodes[i] = node;
271 if (ctx->compat)
272 user_data += sizeof(struct compat_iovec);
273 else
274 user_data += sizeof(struct iovec);
275 }
276 return done ? done : err;
277}
278
279static int __io_register_rsrc_update(struct io_ring_ctx *ctx, unsigned type,
280 struct io_uring_rsrc_update2 *up,
281 unsigned nr_args)
282{
283 __u32 tmp;
284
285 lockdep_assert_held(&ctx->uring_lock);
286
287 if (check_add_overflow(up->offset, nr_args, &tmp))
288 return -EOVERFLOW;
289
290 switch (type) {
291 case IORING_RSRC_FILE:
292 return __io_sqe_files_update(ctx, up, nr_args);
293 case IORING_RSRC_BUFFER:
294 return __io_sqe_buffers_update(ctx, up, nr_args);
295 }
296 return -EINVAL;
297}
298
299int io_register_files_update(struct io_ring_ctx *ctx, void __user *arg,
300 unsigned nr_args)
301{
302 struct io_uring_rsrc_update2 up;
303
304 if (!nr_args)
305 return -EINVAL;
306 memset(&up, 0, sizeof(up));
307 if (copy_from_user(&up, arg, sizeof(struct io_uring_rsrc_update)))
308 return -EFAULT;
309 if (up.resv || up.resv2)
310 return -EINVAL;
311 return __io_register_rsrc_update(ctx, IORING_RSRC_FILE, &up, nr_args);
312}
313
314int io_register_rsrc_update(struct io_ring_ctx *ctx, void __user *arg,
315 unsigned size, unsigned type)
316{
317 struct io_uring_rsrc_update2 up;
318
319 if (size != sizeof(up))
320 return -EINVAL;
321 if (copy_from_user(&up, arg, sizeof(up)))
322 return -EFAULT;
323 if (!up.nr || up.resv || up.resv2)
324 return -EINVAL;
325 return __io_register_rsrc_update(ctx, type, &up, up.nr);
326}
327
328__cold int io_register_rsrc(struct io_ring_ctx *ctx, void __user *arg,
329 unsigned int size, unsigned int type)
330{
331 struct io_uring_rsrc_register rr;
332
333 /* keep it extendible */
334 if (size != sizeof(rr))
335 return -EINVAL;
336
337 memset(&rr, 0, sizeof(rr));
338 if (copy_from_user(&rr, arg, size))
339 return -EFAULT;
340 if (!rr.nr || rr.resv2)
341 return -EINVAL;
342 if (rr.flags & ~IORING_RSRC_REGISTER_SPARSE)
343 return -EINVAL;
344
345 switch (type) {
346 case IORING_RSRC_FILE:
347 if (rr.flags & IORING_RSRC_REGISTER_SPARSE && rr.data)
348 break;
349 return io_sqe_files_register(ctx, u64_to_user_ptr(rr.data),
350 rr.nr, u64_to_user_ptr(rr.tags));
351 case IORING_RSRC_BUFFER:
352 if (rr.flags & IORING_RSRC_REGISTER_SPARSE && rr.data)
353 break;
354 return io_sqe_buffers_register(ctx, u64_to_user_ptr(rr.data),
355 rr.nr, u64_to_user_ptr(rr.tags));
356 }
357 return -EINVAL;
358}
359
360int io_files_update_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
361{
362 struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update);
363
364 if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT)))
365 return -EINVAL;
366 if (sqe->rw_flags || sqe->splice_fd_in)
367 return -EINVAL;
368
369 up->offset = READ_ONCE(sqe->off);
370 up->nr_args = READ_ONCE(sqe->len);
371 if (!up->nr_args)
372 return -EINVAL;
373 up->arg = READ_ONCE(sqe->addr);
374 return 0;
375}
376
377static int io_files_update_with_index_alloc(struct io_kiocb *req,
378 unsigned int issue_flags)
379{
380 struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update);
381 __s32 __user *fds = u64_to_user_ptr(up->arg);
382 unsigned int done;
383 struct file *file;
384 int ret, fd;
385
386 if (!req->ctx->file_table.data.nr)
387 return -ENXIO;
388
389 for (done = 0; done < up->nr_args; done++) {
390 if (copy_from_user(&fd, &fds[done], sizeof(fd))) {
391 ret = -EFAULT;
392 break;
393 }
394
395 file = fget(fd);
396 if (!file) {
397 ret = -EBADF;
398 break;
399 }
400 ret = io_fixed_fd_install(req, issue_flags, file,
401 IORING_FILE_INDEX_ALLOC);
402 if (ret < 0)
403 break;
404 if (copy_to_user(&fds[done], &ret, sizeof(ret))) {
405 __io_close_fixed(req->ctx, issue_flags, ret);
406 ret = -EFAULT;
407 break;
408 }
409 }
410
411 if (done)
412 return done;
413 return ret;
414}
415
416int io_files_update(struct io_kiocb *req, unsigned int issue_flags)
417{
418 struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update);
419 struct io_ring_ctx *ctx = req->ctx;
420 struct io_uring_rsrc_update2 up2;
421 int ret;
422
423 up2.offset = up->offset;
424 up2.data = up->arg;
425 up2.nr = 0;
426 up2.tags = 0;
427 up2.resv = 0;
428 up2.resv2 = 0;
429
430 if (up->offset == IORING_FILE_INDEX_ALLOC) {
431 ret = io_files_update_with_index_alloc(req, issue_flags);
432 } else {
433 io_ring_submit_lock(ctx, issue_flags);
434 ret = __io_register_rsrc_update(ctx, IORING_RSRC_FILE,
435 &up2, up->nr_args);
436 io_ring_submit_unlock(ctx, issue_flags);
437 }
438
439 if (ret < 0)
440 req_set_fail(req);
441 io_req_set_res(req, ret, 0);
442 return IOU_OK;
443}
444
445void io_free_rsrc_node(struct io_ring_ctx *ctx, struct io_rsrc_node *node)
446{
447 lockdep_assert_held(&ctx->uring_lock);
448
449 if (node->tag)
450 io_post_aux_cqe(ctx, node->tag, 0, 0);
451
452 switch (node->type) {
453 case IORING_RSRC_FILE:
454 if (io_slot_file(node))
455 fput(io_slot_file(node));
456 break;
457 case IORING_RSRC_BUFFER:
458 if (node->buf)
459 io_buffer_unmap(ctx, node);
460 break;
461 default:
462 WARN_ON_ONCE(1);
463 break;
464 }
465
466 kfree(node);
467}
468
469int io_sqe_files_unregister(struct io_ring_ctx *ctx)
470{
471 if (!ctx->file_table.data.nr)
472 return -ENXIO;
473
474 io_free_file_tables(ctx, &ctx->file_table);
475 io_file_table_set_alloc_range(ctx, 0, 0);
476 return 0;
477}
478
479int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
480 unsigned nr_args, u64 __user *tags)
481{
482 __s32 __user *fds = (__s32 __user *) arg;
483 struct file *file;
484 int fd, ret;
485 unsigned i;
486
487 if (ctx->file_table.data.nr)
488 return -EBUSY;
489 if (!nr_args)
490 return -EINVAL;
491 if (nr_args > IORING_MAX_FIXED_FILES)
492 return -EMFILE;
493 if (nr_args > rlimit(RLIMIT_NOFILE))
494 return -EMFILE;
495 if (!io_alloc_file_tables(ctx, &ctx->file_table, nr_args))
496 return -ENOMEM;
497
498 for (i = 0; i < nr_args; i++) {
499 struct io_rsrc_node *node;
500 u64 tag = 0;
501
502 ret = -EFAULT;
503 if (tags && copy_from_user(&tag, &tags[i], sizeof(tag)))
504 goto fail;
505 if (fds && copy_from_user(&fd, &fds[i], sizeof(fd)))
506 goto fail;
507 /* allow sparse sets */
508 if (!fds || fd == -1) {
509 ret = -EINVAL;
510 if (tag)
511 goto fail;
512 continue;
513 }
514
515 file = fget(fd);
516 ret = -EBADF;
517 if (unlikely(!file))
518 goto fail;
519
520 /*
521 * Don't allow io_uring instances to be registered.
522 */
523 if (io_is_uring_fops(file)) {
524 fput(file);
525 goto fail;
526 }
527 ret = -ENOMEM;
528 node = io_rsrc_node_alloc(ctx, IORING_RSRC_FILE);
529 if (!node) {
530 fput(file);
531 goto fail;
532 }
533 if (tag)
534 node->tag = tag;
535 ctx->file_table.data.nodes[i] = node;
536 io_fixed_file_set(node, file);
537 io_file_bitmap_set(&ctx->file_table, i);
538 }
539
540 /* default it to the whole table */
541 io_file_table_set_alloc_range(ctx, 0, ctx->file_table.data.nr);
542 return 0;
543fail:
544 io_sqe_files_unregister(ctx);
545 return ret;
546}
547
548int io_sqe_buffers_unregister(struct io_ring_ctx *ctx)
549{
550 if (!ctx->buf_table.nr)
551 return -ENXIO;
552 io_rsrc_data_free(ctx, &ctx->buf_table);
553 return 0;
554}
555
556/*
557 * Not super efficient, but this is just a registration time. And we do cache
558 * the last compound head, so generally we'll only do a full search if we don't
559 * match that one.
560 *
561 * We check if the given compound head page has already been accounted, to
562 * avoid double accounting it. This allows us to account the full size of the
563 * page, not just the constituent pages of a huge page.
564 */
565static bool headpage_already_acct(struct io_ring_ctx *ctx, struct page **pages,
566 int nr_pages, struct page *hpage)
567{
568 int i, j;
569
570 /* check current page array */
571 for (i = 0; i < nr_pages; i++) {
572 if (!PageCompound(pages[i]))
573 continue;
574 if (compound_head(pages[i]) == hpage)
575 return true;
576 }
577
578 /* check previously registered pages */
579 for (i = 0; i < ctx->buf_table.nr; i++) {
580 struct io_rsrc_node *node = ctx->buf_table.nodes[i];
581 struct io_mapped_ubuf *imu;
582
583 if (!node)
584 continue;
585 imu = node->buf;
586 for (j = 0; j < imu->nr_bvecs; j++) {
587 if (!PageCompound(imu->bvec[j].bv_page))
588 continue;
589 if (compound_head(imu->bvec[j].bv_page) == hpage)
590 return true;
591 }
592 }
593
594 return false;
595}
596
597static int io_buffer_account_pin(struct io_ring_ctx *ctx, struct page **pages,
598 int nr_pages, struct io_mapped_ubuf *imu,
599 struct page **last_hpage)
600{
601 int i, ret;
602
603 imu->acct_pages = 0;
604 for (i = 0; i < nr_pages; i++) {
605 if (!PageCompound(pages[i])) {
606 imu->acct_pages++;
607 } else {
608 struct page *hpage;
609
610 hpage = compound_head(pages[i]);
611 if (hpage == *last_hpage)
612 continue;
613 *last_hpage = hpage;
614 if (headpage_already_acct(ctx, pages, i, hpage))
615 continue;
616 imu->acct_pages += page_size(hpage) >> PAGE_SHIFT;
617 }
618 }
619
620 if (!imu->acct_pages)
621 return 0;
622
623 ret = io_account_mem(ctx, imu->acct_pages);
624 if (ret)
625 imu->acct_pages = 0;
626 return ret;
627}
628
629static bool io_do_coalesce_buffer(struct page ***pages, int *nr_pages,
630 struct io_imu_folio_data *data, int nr_folios)
631{
632 struct page **page_array = *pages, **new_array = NULL;
633 int nr_pages_left = *nr_pages, i, j;
634
635 /* Store head pages only*/
636 new_array = kvmalloc_array(nr_folios, sizeof(struct page *),
637 GFP_KERNEL);
638 if (!new_array)
639 return false;
640
641 new_array[0] = compound_head(page_array[0]);
642 /*
643 * The pages are bound to the folio, it doesn't
644 * actually unpin them but drops all but one reference,
645 * which is usually put down by io_buffer_unmap().
646 * Note, needs a better helper.
647 */
648 if (data->nr_pages_head > 1)
649 unpin_user_pages(&page_array[1], data->nr_pages_head - 1);
650
651 j = data->nr_pages_head;
652 nr_pages_left -= data->nr_pages_head;
653 for (i = 1; i < nr_folios; i++) {
654 unsigned int nr_unpin;
655
656 new_array[i] = page_array[j];
657 nr_unpin = min_t(unsigned int, nr_pages_left - 1,
658 data->nr_pages_mid - 1);
659 if (nr_unpin)
660 unpin_user_pages(&page_array[j+1], nr_unpin);
661 j += data->nr_pages_mid;
662 nr_pages_left -= data->nr_pages_mid;
663 }
664 kvfree(page_array);
665 *pages = new_array;
666 *nr_pages = nr_folios;
667 return true;
668}
669
670static bool io_try_coalesce_buffer(struct page ***pages, int *nr_pages,
671 struct io_imu_folio_data *data)
672{
673 struct page **page_array = *pages;
674 struct folio *folio = page_folio(page_array[0]);
675 unsigned int count = 1, nr_folios = 1;
676 int i;
677
678 if (*nr_pages <= 1)
679 return false;
680
681 data->nr_pages_mid = folio_nr_pages(folio);
682 if (data->nr_pages_mid == 1)
683 return false;
684
685 data->folio_shift = folio_shift(folio);
686 /*
687 * Check if pages are contiguous inside a folio, and all folios have
688 * the same page count except for the head and tail.
689 */
690 for (i = 1; i < *nr_pages; i++) {
691 if (page_folio(page_array[i]) == folio &&
692 page_array[i] == page_array[i-1] + 1) {
693 count++;
694 continue;
695 }
696
697 if (nr_folios == 1) {
698 if (folio_page_idx(folio, page_array[i-1]) !=
699 data->nr_pages_mid - 1)
700 return false;
701
702 data->nr_pages_head = count;
703 } else if (count != data->nr_pages_mid) {
704 return false;
705 }
706
707 folio = page_folio(page_array[i]);
708 if (folio_size(folio) != (1UL << data->folio_shift) ||
709 folio_page_idx(folio, page_array[i]) != 0)
710 return false;
711
712 count = 1;
713 nr_folios++;
714 }
715 if (nr_folios == 1)
716 data->nr_pages_head = count;
717
718 return io_do_coalesce_buffer(pages, nr_pages, data, nr_folios);
719}
720
721static struct io_rsrc_node *io_sqe_buffer_register(struct io_ring_ctx *ctx,
722 struct iovec *iov,
723 struct page **last_hpage)
724{
725 struct io_mapped_ubuf *imu = NULL;
726 struct page **pages = NULL;
727 struct io_rsrc_node *node;
728 unsigned long off;
729 size_t size;
730 int ret, nr_pages, i;
731 struct io_imu_folio_data data;
732 bool coalesced;
733
734 if (!iov->iov_base)
735 return NULL;
736
737 node = io_rsrc_node_alloc(ctx, IORING_RSRC_BUFFER);
738 if (!node)
739 return ERR_PTR(-ENOMEM);
740 node->buf = NULL;
741
742 ret = -ENOMEM;
743 pages = io_pin_pages((unsigned long) iov->iov_base, iov->iov_len,
744 &nr_pages);
745 if (IS_ERR(pages)) {
746 ret = PTR_ERR(pages);
747 pages = NULL;
748 goto done;
749 }
750
751 /* If it's huge page(s), try to coalesce them into fewer bvec entries */
752 coalesced = io_try_coalesce_buffer(&pages, &nr_pages, &data);
753
754 imu = kvmalloc(struct_size(imu, bvec, nr_pages), GFP_KERNEL);
755 if (!imu)
756 goto done;
757
758 ret = io_buffer_account_pin(ctx, pages, nr_pages, imu, last_hpage);
759 if (ret) {
760 unpin_user_pages(pages, nr_pages);
761 goto done;
762 }
763
764 size = iov->iov_len;
765 /* store original address for later verification */
766 imu->ubuf = (unsigned long) iov->iov_base;
767 imu->len = iov->iov_len;
768 imu->nr_bvecs = nr_pages;
769 imu->folio_shift = PAGE_SHIFT;
770 if (coalesced)
771 imu->folio_shift = data.folio_shift;
772 refcount_set(&imu->refs, 1);
773 off = (unsigned long) iov->iov_base & ((1UL << imu->folio_shift) - 1);
774 node->buf = imu;
775 ret = 0;
776
777 for (i = 0; i < nr_pages; i++) {
778 size_t vec_len;
779
780 vec_len = min_t(size_t, size, (1UL << imu->folio_shift) - off);
781 bvec_set_page(&imu->bvec[i], pages[i], vec_len, off);
782 off = 0;
783 size -= vec_len;
784 }
785done:
786 if (ret) {
787 kvfree(imu);
788 if (node)
789 io_put_rsrc_node(ctx, node);
790 node = ERR_PTR(ret);
791 }
792 kvfree(pages);
793 return node;
794}
795
796int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
797 unsigned int nr_args, u64 __user *tags)
798{
799 struct page *last_hpage = NULL;
800 struct io_rsrc_data data;
801 struct iovec fast_iov, *iov = &fast_iov;
802 const struct iovec __user *uvec;
803 int i, ret;
804
805 BUILD_BUG_ON(IORING_MAX_REG_BUFFERS >= (1u << 16));
806
807 if (ctx->buf_table.nr)
808 return -EBUSY;
809 if (!nr_args || nr_args > IORING_MAX_REG_BUFFERS)
810 return -EINVAL;
811 ret = io_rsrc_data_alloc(&data, nr_args);
812 if (ret)
813 return ret;
814
815 if (!arg)
816 memset(iov, 0, sizeof(*iov));
817
818 for (i = 0; i < nr_args; i++) {
819 struct io_rsrc_node *node;
820 u64 tag = 0;
821
822 if (arg) {
823 uvec = (struct iovec __user *) arg;
824 iov = iovec_from_user(uvec, 1, 1, &fast_iov, ctx->compat);
825 if (IS_ERR(iov)) {
826 ret = PTR_ERR(iov);
827 break;
828 }
829 ret = io_buffer_validate(iov);
830 if (ret)
831 break;
832 if (ctx->compat)
833 arg += sizeof(struct compat_iovec);
834 else
835 arg += sizeof(struct iovec);
836 }
837
838 if (tags) {
839 if (copy_from_user(&tag, &tags[i], sizeof(tag))) {
840 ret = -EFAULT;
841 break;
842 }
843 }
844
845 node = io_sqe_buffer_register(ctx, iov, &last_hpage);
846 if (IS_ERR(node)) {
847 ret = PTR_ERR(node);
848 break;
849 }
850 if (tag) {
851 if (!node) {
852 ret = -EINVAL;
853 break;
854 }
855 node->tag = tag;
856 }
857 data.nodes[i] = node;
858 }
859
860 ctx->buf_table = data;
861 if (ret)
862 io_sqe_buffers_unregister(ctx);
863 return ret;
864}
865
866int io_import_fixed(int ddir, struct iov_iter *iter,
867 struct io_mapped_ubuf *imu,
868 u64 buf_addr, size_t len)
869{
870 u64 buf_end;
871 size_t offset;
872
873 if (WARN_ON_ONCE(!imu))
874 return -EFAULT;
875 if (unlikely(check_add_overflow(buf_addr, (u64)len, &buf_end)))
876 return -EFAULT;
877 /* not inside the mapped region */
878 if (unlikely(buf_addr < imu->ubuf || buf_end > (imu->ubuf + imu->len)))
879 return -EFAULT;
880
881 /*
882 * Might not be a start of buffer, set size appropriately
883 * and advance us to the beginning.
884 */
885 offset = buf_addr - imu->ubuf;
886 iov_iter_bvec(iter, ddir, imu->bvec, imu->nr_bvecs, offset + len);
887
888 if (offset) {
889 /*
890 * Don't use iov_iter_advance() here, as it's really slow for
891 * using the latter parts of a big fixed buffer - it iterates
892 * over each segment manually. We can cheat a bit here, because
893 * we know that:
894 *
895 * 1) it's a BVEC iter, we set it up
896 * 2) all bvecs are the same in size, except potentially the
897 * first and last bvec
898 *
899 * So just find our index, and adjust the iterator afterwards.
900 * If the offset is within the first bvec (or the whole first
901 * bvec, just use iov_iter_advance(). This makes it easier
902 * since we can just skip the first segment, which may not
903 * be folio_size aligned.
904 */
905 const struct bio_vec *bvec = imu->bvec;
906
907 if (offset < bvec->bv_len) {
908 iter->count -= offset;
909 iter->iov_offset = offset;
910 } else {
911 unsigned long seg_skip;
912
913 /* skip first vec */
914 offset -= bvec->bv_len;
915 seg_skip = 1 + (offset >> imu->folio_shift);
916
917 iter->bvec += seg_skip;
918 iter->nr_segs -= seg_skip;
919 iter->count -= bvec->bv_len + offset;
920 iter->iov_offset = offset & ((1UL << imu->folio_shift) - 1);
921 }
922 }
923
924 return 0;
925}
926
927static int io_clone_buffers(struct io_ring_ctx *ctx, struct io_ring_ctx *src_ctx,
928 struct io_uring_clone_buffers *arg)
929{
930 struct io_rsrc_data data;
931 int i, ret, off, nr;
932 unsigned int nbufs;
933
934 /*
935 * Accounting state is shared between the two rings; that only works if
936 * both rings are accounted towards the same counters.
937 */
938 if (ctx->user != src_ctx->user || ctx->mm_account != src_ctx->mm_account)
939 return -EINVAL;
940
941 /* if offsets are given, must have nr specified too */
942 if (!arg->nr && (arg->dst_off || arg->src_off))
943 return -EINVAL;
944 /* not allowed unless REPLACE is set */
945 if (ctx->buf_table.nr && !(arg->flags & IORING_REGISTER_DST_REPLACE))
946 return -EBUSY;
947
948 nbufs = READ_ONCE(src_ctx->buf_table.nr);
949 if (!arg->nr)
950 arg->nr = nbufs;
951 else if (arg->nr > nbufs)
952 return -EINVAL;
953 else if (arg->nr > IORING_MAX_REG_BUFFERS)
954 return -EINVAL;
955 if (check_add_overflow(arg->nr, arg->dst_off, &nbufs))
956 return -EOVERFLOW;
957
958 ret = io_rsrc_data_alloc(&data, max(nbufs, ctx->buf_table.nr));
959 if (ret)
960 return ret;
961
962 /* Fill entries in data from dst that won't overlap with src */
963 for (i = 0; i < min(arg->dst_off, ctx->buf_table.nr); i++) {
964 struct io_rsrc_node *src_node = ctx->buf_table.nodes[i];
965
966 if (src_node) {
967 data.nodes[i] = src_node;
968 src_node->refs++;
969 }
970 }
971
972 /*
973 * Drop our own lock here. We'll setup the data we need and reference
974 * the source buffers, then re-grab, check, and assign at the end.
975 */
976 mutex_unlock(&ctx->uring_lock);
977
978 mutex_lock(&src_ctx->uring_lock);
979 ret = -ENXIO;
980 nbufs = src_ctx->buf_table.nr;
981 if (!nbufs)
982 goto out_unlock;
983 ret = -EINVAL;
984 if (!arg->nr)
985 arg->nr = nbufs;
986 else if (arg->nr > nbufs)
987 goto out_unlock;
988 ret = -EOVERFLOW;
989 if (check_add_overflow(arg->nr, arg->src_off, &off))
990 goto out_unlock;
991 if (off > nbufs)
992 goto out_unlock;
993
994 off = arg->dst_off;
995 i = arg->src_off;
996 nr = arg->nr;
997 while (nr--) {
998 struct io_rsrc_node *dst_node, *src_node;
999
1000 src_node = io_rsrc_node_lookup(&src_ctx->buf_table, i);
1001 if (!src_node) {
1002 dst_node = NULL;
1003 } else {
1004 dst_node = io_rsrc_node_alloc(ctx, IORING_RSRC_BUFFER);
1005 if (!dst_node) {
1006 ret = -ENOMEM;
1007 goto out_unlock;
1008 }
1009
1010 refcount_inc(&src_node->buf->refs);
1011 dst_node->buf = src_node->buf;
1012 }
1013 data.nodes[off++] = dst_node;
1014 i++;
1015 }
1016
1017 /* Have a ref on the bufs now, drop src lock and re-grab our own lock */
1018 mutex_unlock(&src_ctx->uring_lock);
1019 mutex_lock(&ctx->uring_lock);
1020
1021 /*
1022 * If asked for replace, put the old table. data->nodes[] holds both
1023 * old and new nodes at this point.
1024 */
1025 if (arg->flags & IORING_REGISTER_DST_REPLACE)
1026 io_rsrc_data_free(ctx, &ctx->buf_table);
1027
1028 /*
1029 * ctx->buf_table should be empty now - either the contents are being
1030 * replaced and we just freed the table, or someone raced setting up
1031 * a buffer table while the clone was happening. If not empty, fall
1032 * through to failure handling.
1033 */
1034 if (!ctx->buf_table.nr) {
1035 ctx->buf_table = data;
1036 return 0;
1037 }
1038
1039 mutex_unlock(&ctx->uring_lock);
1040 mutex_lock(&src_ctx->uring_lock);
1041 /* someone raced setting up buffers, dump ours */
1042 ret = -EBUSY;
1043out_unlock:
1044 io_rsrc_data_free(ctx, &data);
1045 mutex_unlock(&src_ctx->uring_lock);
1046 mutex_lock(&ctx->uring_lock);
1047 return ret;
1048}
1049
1050/*
1051 * Copy the registered buffers from the source ring whose file descriptor
1052 * is given in the src_fd to the current ring. This is identical to registering
1053 * the buffers with ctx, except faster as mappings already exist.
1054 *
1055 * Since the memory is already accounted once, don't account it again.
1056 */
1057int io_register_clone_buffers(struct io_ring_ctx *ctx, void __user *arg)
1058{
1059 struct io_uring_clone_buffers buf;
1060 bool registered_src;
1061 struct file *file;
1062 int ret;
1063
1064 if (copy_from_user(&buf, arg, sizeof(buf)))
1065 return -EFAULT;
1066 if (buf.flags & ~(IORING_REGISTER_SRC_REGISTERED|IORING_REGISTER_DST_REPLACE))
1067 return -EINVAL;
1068 if (!(buf.flags & IORING_REGISTER_DST_REPLACE) && ctx->buf_table.nr)
1069 return -EBUSY;
1070 if (memchr_inv(buf.pad, 0, sizeof(buf.pad)))
1071 return -EINVAL;
1072
1073 registered_src = (buf.flags & IORING_REGISTER_SRC_REGISTERED) != 0;
1074 file = io_uring_register_get_file(buf.src_fd, registered_src);
1075 if (IS_ERR(file))
1076 return PTR_ERR(file);
1077 ret = io_clone_buffers(ctx, file->private_data, &buf);
1078 if (!registered_src)
1079 fput(file);
1080 return ret;
1081}