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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
19struct io_rsrc_update {
20 struct file *file;
21 u64 arg;
22 u32 nr_args;
23 u32 offset;
24};
25
26static void io_rsrc_buf_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc);
27static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov,
28 struct io_mapped_ubuf **pimu,
29 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
35static const struct io_mapped_ubuf dummy_ubuf = {
36 /* set invalid range, so io_import_fixed() fails meeting it */
37 .ubuf = -1UL,
38 .ubuf_end = 0,
39};
40
41int __io_account_mem(struct user_struct *user, unsigned long nr_pages)
42{
43 unsigned long page_limit, cur_pages, new_pages;
44
45 if (!nr_pages)
46 return 0;
47
48 /* Don't allow more pages than we can safely lock */
49 page_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
50
51 cur_pages = atomic_long_read(&user->locked_vm);
52 do {
53 new_pages = cur_pages + nr_pages;
54 if (new_pages > page_limit)
55 return -ENOMEM;
56 } while (!atomic_long_try_cmpxchg(&user->locked_vm,
57 &cur_pages, new_pages));
58 return 0;
59}
60
61static void io_unaccount_mem(struct io_ring_ctx *ctx, unsigned long nr_pages)
62{
63 if (ctx->user)
64 __io_unaccount_mem(ctx->user, nr_pages);
65
66 if (ctx->mm_account)
67 atomic64_sub(nr_pages, &ctx->mm_account->pinned_vm);
68}
69
70static int io_account_mem(struct io_ring_ctx *ctx, unsigned long nr_pages)
71{
72 int ret;
73
74 if (ctx->user) {
75 ret = __io_account_mem(ctx->user, nr_pages);
76 if (ret)
77 return ret;
78 }
79
80 if (ctx->mm_account)
81 atomic64_add(nr_pages, &ctx->mm_account->pinned_vm);
82
83 return 0;
84}
85
86static int io_copy_iov(struct io_ring_ctx *ctx, struct iovec *dst,
87 void __user *arg, unsigned index)
88{
89 struct iovec __user *src;
90
91#ifdef CONFIG_COMPAT
92 if (ctx->compat) {
93 struct compat_iovec __user *ciovs;
94 struct compat_iovec ciov;
95
96 ciovs = (struct compat_iovec __user *) arg;
97 if (copy_from_user(&ciov, &ciovs[index], sizeof(ciov)))
98 return -EFAULT;
99
100 dst->iov_base = u64_to_user_ptr((u64)ciov.iov_base);
101 dst->iov_len = ciov.iov_len;
102 return 0;
103 }
104#endif
105 src = (struct iovec __user *) arg;
106 if (copy_from_user(dst, &src[index], sizeof(*dst)))
107 return -EFAULT;
108 return 0;
109}
110
111static int io_buffer_validate(struct iovec *iov)
112{
113 unsigned long tmp, acct_len = iov->iov_len + (PAGE_SIZE - 1);
114
115 /*
116 * Don't impose further limits on the size and buffer
117 * constraints here, we'll -EINVAL later when IO is
118 * submitted if they are wrong.
119 */
120 if (!iov->iov_base)
121 return iov->iov_len ? -EFAULT : 0;
122 if (!iov->iov_len)
123 return -EFAULT;
124
125 /* arbitrary limit, but we need something */
126 if (iov->iov_len > SZ_1G)
127 return -EFAULT;
128
129 if (check_add_overflow((unsigned long)iov->iov_base, acct_len, &tmp))
130 return -EOVERFLOW;
131
132 return 0;
133}
134
135static void io_buffer_unmap(struct io_ring_ctx *ctx, struct io_mapped_ubuf **slot)
136{
137 struct io_mapped_ubuf *imu = *slot;
138 unsigned int i;
139
140 if (imu != &dummy_ubuf) {
141 for (i = 0; i < imu->nr_bvecs; i++)
142 unpin_user_page(imu->bvec[i].bv_page);
143 if (imu->acct_pages)
144 io_unaccount_mem(ctx, imu->acct_pages);
145 kvfree(imu);
146 }
147 *slot = NULL;
148}
149
150static void io_rsrc_put_work(struct io_rsrc_node *node)
151{
152 struct io_rsrc_put *prsrc = &node->item;
153
154 if (prsrc->tag)
155 io_post_aux_cqe(node->ctx, prsrc->tag, 0, 0);
156
157 switch (node->type) {
158 case IORING_RSRC_FILE:
159 fput(prsrc->file);
160 break;
161 case IORING_RSRC_BUFFER:
162 io_rsrc_buf_put(node->ctx, prsrc);
163 break;
164 default:
165 WARN_ON_ONCE(1);
166 break;
167 }
168}
169
170void io_rsrc_node_destroy(struct io_ring_ctx *ctx, struct io_rsrc_node *node)
171{
172 if (!io_alloc_cache_put(&ctx->rsrc_node_cache, &node->cache))
173 kfree(node);
174}
175
176void io_rsrc_node_ref_zero(struct io_rsrc_node *node)
177 __must_hold(&node->ctx->uring_lock)
178{
179 struct io_ring_ctx *ctx = node->ctx;
180
181 while (!list_empty(&ctx->rsrc_ref_list)) {
182 node = list_first_entry(&ctx->rsrc_ref_list,
183 struct io_rsrc_node, node);
184 /* recycle ref nodes in order */
185 if (node->refs)
186 break;
187 list_del(&node->node);
188
189 if (likely(!node->empty))
190 io_rsrc_put_work(node);
191 io_rsrc_node_destroy(ctx, node);
192 }
193 if (list_empty(&ctx->rsrc_ref_list) && unlikely(ctx->rsrc_quiesce))
194 wake_up_all(&ctx->rsrc_quiesce_wq);
195}
196
197struct io_rsrc_node *io_rsrc_node_alloc(struct io_ring_ctx *ctx)
198{
199 struct io_rsrc_node *ref_node;
200 struct io_cache_entry *entry;
201
202 entry = io_alloc_cache_get(&ctx->rsrc_node_cache);
203 if (entry) {
204 ref_node = container_of(entry, struct io_rsrc_node, cache);
205 } else {
206 ref_node = kzalloc(sizeof(*ref_node), GFP_KERNEL);
207 if (!ref_node)
208 return NULL;
209 }
210
211 ref_node->ctx = ctx;
212 ref_node->empty = 0;
213 ref_node->refs = 1;
214 return ref_node;
215}
216
217__cold static int io_rsrc_ref_quiesce(struct io_rsrc_data *data,
218 struct io_ring_ctx *ctx)
219{
220 struct io_rsrc_node *backup;
221 DEFINE_WAIT(we);
222 int ret;
223
224 /* As We may drop ->uring_lock, other task may have started quiesce */
225 if (data->quiesce)
226 return -ENXIO;
227
228 backup = io_rsrc_node_alloc(ctx);
229 if (!backup)
230 return -ENOMEM;
231 ctx->rsrc_node->empty = true;
232 ctx->rsrc_node->type = -1;
233 list_add_tail(&ctx->rsrc_node->node, &ctx->rsrc_ref_list);
234 io_put_rsrc_node(ctx, ctx->rsrc_node);
235 ctx->rsrc_node = backup;
236
237 if (list_empty(&ctx->rsrc_ref_list))
238 return 0;
239
240 if (ctx->flags & IORING_SETUP_DEFER_TASKRUN) {
241 atomic_set(&ctx->cq_wait_nr, 1);
242 smp_mb();
243 }
244
245 ctx->rsrc_quiesce++;
246 data->quiesce = true;
247 do {
248 prepare_to_wait(&ctx->rsrc_quiesce_wq, &we, TASK_INTERRUPTIBLE);
249 mutex_unlock(&ctx->uring_lock);
250
251 ret = io_run_task_work_sig(ctx);
252 if (ret < 0) {
253 mutex_lock(&ctx->uring_lock);
254 if (list_empty(&ctx->rsrc_ref_list))
255 ret = 0;
256 break;
257 }
258
259 schedule();
260 __set_current_state(TASK_RUNNING);
261 mutex_lock(&ctx->uring_lock);
262 ret = 0;
263 } while (!list_empty(&ctx->rsrc_ref_list));
264
265 finish_wait(&ctx->rsrc_quiesce_wq, &we);
266 data->quiesce = false;
267 ctx->rsrc_quiesce--;
268
269 if (ctx->flags & IORING_SETUP_DEFER_TASKRUN) {
270 atomic_set(&ctx->cq_wait_nr, 0);
271 smp_mb();
272 }
273 return ret;
274}
275
276static void io_free_page_table(void **table, size_t size)
277{
278 unsigned i, nr_tables = DIV_ROUND_UP(size, PAGE_SIZE);
279
280 for (i = 0; i < nr_tables; i++)
281 kfree(table[i]);
282 kfree(table);
283}
284
285static void io_rsrc_data_free(struct io_rsrc_data *data)
286{
287 size_t size = data->nr * sizeof(data->tags[0][0]);
288
289 if (data->tags)
290 io_free_page_table((void **)data->tags, size);
291 kfree(data);
292}
293
294static __cold void **io_alloc_page_table(size_t size)
295{
296 unsigned i, nr_tables = DIV_ROUND_UP(size, PAGE_SIZE);
297 size_t init_size = size;
298 void **table;
299
300 table = kcalloc(nr_tables, sizeof(*table), GFP_KERNEL_ACCOUNT);
301 if (!table)
302 return NULL;
303
304 for (i = 0; i < nr_tables; i++) {
305 unsigned int this_size = min_t(size_t, size, PAGE_SIZE);
306
307 table[i] = kzalloc(this_size, GFP_KERNEL_ACCOUNT);
308 if (!table[i]) {
309 io_free_page_table(table, init_size);
310 return NULL;
311 }
312 size -= this_size;
313 }
314 return table;
315}
316
317__cold static int io_rsrc_data_alloc(struct io_ring_ctx *ctx, int type,
318 u64 __user *utags,
319 unsigned nr, struct io_rsrc_data **pdata)
320{
321 struct io_rsrc_data *data;
322 int ret = 0;
323 unsigned i;
324
325 data = kzalloc(sizeof(*data), GFP_KERNEL);
326 if (!data)
327 return -ENOMEM;
328 data->tags = (u64 **)io_alloc_page_table(nr * sizeof(data->tags[0][0]));
329 if (!data->tags) {
330 kfree(data);
331 return -ENOMEM;
332 }
333
334 data->nr = nr;
335 data->ctx = ctx;
336 data->rsrc_type = type;
337 if (utags) {
338 ret = -EFAULT;
339 for (i = 0; i < nr; i++) {
340 u64 *tag_slot = io_get_tag_slot(data, i);
341
342 if (copy_from_user(tag_slot, &utags[i],
343 sizeof(*tag_slot)))
344 goto fail;
345 }
346 }
347 *pdata = data;
348 return 0;
349fail:
350 io_rsrc_data_free(data);
351 return ret;
352}
353
354static int __io_sqe_files_update(struct io_ring_ctx *ctx,
355 struct io_uring_rsrc_update2 *up,
356 unsigned nr_args)
357{
358 u64 __user *tags = u64_to_user_ptr(up->tags);
359 __s32 __user *fds = u64_to_user_ptr(up->data);
360 struct io_rsrc_data *data = ctx->file_data;
361 struct io_fixed_file *file_slot;
362 int fd, i, err = 0;
363 unsigned int done;
364
365 if (!ctx->file_data)
366 return -ENXIO;
367 if (up->offset + nr_args > ctx->nr_user_files)
368 return -EINVAL;
369
370 for (done = 0; done < nr_args; done++) {
371 u64 tag = 0;
372
373 if ((tags && copy_from_user(&tag, &tags[done], sizeof(tag))) ||
374 copy_from_user(&fd, &fds[done], sizeof(fd))) {
375 err = -EFAULT;
376 break;
377 }
378 if ((fd == IORING_REGISTER_FILES_SKIP || fd == -1) && tag) {
379 err = -EINVAL;
380 break;
381 }
382 if (fd == IORING_REGISTER_FILES_SKIP)
383 continue;
384
385 i = array_index_nospec(up->offset + done, ctx->nr_user_files);
386 file_slot = io_fixed_file_slot(&ctx->file_table, i);
387
388 if (file_slot->file_ptr) {
389 err = io_queue_rsrc_removal(data, i,
390 io_slot_file(file_slot));
391 if (err)
392 break;
393 file_slot->file_ptr = 0;
394 io_file_bitmap_clear(&ctx->file_table, i);
395 }
396 if (fd != -1) {
397 struct file *file = fget(fd);
398
399 if (!file) {
400 err = -EBADF;
401 break;
402 }
403 /*
404 * Don't allow io_uring instances to be registered.
405 */
406 if (io_is_uring_fops(file)) {
407 fput(file);
408 err = -EBADF;
409 break;
410 }
411 *io_get_tag_slot(data, i) = tag;
412 io_fixed_file_set(file_slot, file);
413 io_file_bitmap_set(&ctx->file_table, i);
414 }
415 }
416 return done ? done : err;
417}
418
419static int __io_sqe_buffers_update(struct io_ring_ctx *ctx,
420 struct io_uring_rsrc_update2 *up,
421 unsigned int nr_args)
422{
423 u64 __user *tags = u64_to_user_ptr(up->tags);
424 struct iovec iov, __user *iovs = u64_to_user_ptr(up->data);
425 struct page *last_hpage = NULL;
426 __u32 done;
427 int i, err;
428
429 if (!ctx->buf_data)
430 return -ENXIO;
431 if (up->offset + nr_args > ctx->nr_user_bufs)
432 return -EINVAL;
433
434 for (done = 0; done < nr_args; done++) {
435 struct io_mapped_ubuf *imu;
436 u64 tag = 0;
437
438 err = io_copy_iov(ctx, &iov, iovs, done);
439 if (err)
440 break;
441 if (tags && copy_from_user(&tag, &tags[done], sizeof(tag))) {
442 err = -EFAULT;
443 break;
444 }
445 err = io_buffer_validate(&iov);
446 if (err)
447 break;
448 if (!iov.iov_base && tag) {
449 err = -EINVAL;
450 break;
451 }
452 err = io_sqe_buffer_register(ctx, &iov, &imu, &last_hpage);
453 if (err)
454 break;
455
456 i = array_index_nospec(up->offset + done, ctx->nr_user_bufs);
457 if (ctx->user_bufs[i] != &dummy_ubuf) {
458 err = io_queue_rsrc_removal(ctx->buf_data, i,
459 ctx->user_bufs[i]);
460 if (unlikely(err)) {
461 io_buffer_unmap(ctx, &imu);
462 break;
463 }
464 ctx->user_bufs[i] = (struct io_mapped_ubuf *)&dummy_ubuf;
465 }
466
467 ctx->user_bufs[i] = imu;
468 *io_get_tag_slot(ctx->buf_data, i) = tag;
469 }
470 return done ? done : err;
471}
472
473static int __io_register_rsrc_update(struct io_ring_ctx *ctx, unsigned type,
474 struct io_uring_rsrc_update2 *up,
475 unsigned nr_args)
476{
477 __u32 tmp;
478
479 lockdep_assert_held(&ctx->uring_lock);
480
481 if (check_add_overflow(up->offset, nr_args, &tmp))
482 return -EOVERFLOW;
483
484 switch (type) {
485 case IORING_RSRC_FILE:
486 return __io_sqe_files_update(ctx, up, nr_args);
487 case IORING_RSRC_BUFFER:
488 return __io_sqe_buffers_update(ctx, up, nr_args);
489 }
490 return -EINVAL;
491}
492
493int io_register_files_update(struct io_ring_ctx *ctx, void __user *arg,
494 unsigned nr_args)
495{
496 struct io_uring_rsrc_update2 up;
497
498 if (!nr_args)
499 return -EINVAL;
500 memset(&up, 0, sizeof(up));
501 if (copy_from_user(&up, arg, sizeof(struct io_uring_rsrc_update)))
502 return -EFAULT;
503 if (up.resv || up.resv2)
504 return -EINVAL;
505 return __io_register_rsrc_update(ctx, IORING_RSRC_FILE, &up, nr_args);
506}
507
508int io_register_rsrc_update(struct io_ring_ctx *ctx, void __user *arg,
509 unsigned size, unsigned type)
510{
511 struct io_uring_rsrc_update2 up;
512
513 if (size != sizeof(up))
514 return -EINVAL;
515 if (copy_from_user(&up, arg, sizeof(up)))
516 return -EFAULT;
517 if (!up.nr || up.resv || up.resv2)
518 return -EINVAL;
519 return __io_register_rsrc_update(ctx, type, &up, up.nr);
520}
521
522__cold int io_register_rsrc(struct io_ring_ctx *ctx, void __user *arg,
523 unsigned int size, unsigned int type)
524{
525 struct io_uring_rsrc_register rr;
526
527 /* keep it extendible */
528 if (size != sizeof(rr))
529 return -EINVAL;
530
531 memset(&rr, 0, sizeof(rr));
532 if (copy_from_user(&rr, arg, size))
533 return -EFAULT;
534 if (!rr.nr || rr.resv2)
535 return -EINVAL;
536 if (rr.flags & ~IORING_RSRC_REGISTER_SPARSE)
537 return -EINVAL;
538
539 switch (type) {
540 case IORING_RSRC_FILE:
541 if (rr.flags & IORING_RSRC_REGISTER_SPARSE && rr.data)
542 break;
543 return io_sqe_files_register(ctx, u64_to_user_ptr(rr.data),
544 rr.nr, u64_to_user_ptr(rr.tags));
545 case IORING_RSRC_BUFFER:
546 if (rr.flags & IORING_RSRC_REGISTER_SPARSE && rr.data)
547 break;
548 return io_sqe_buffers_register(ctx, u64_to_user_ptr(rr.data),
549 rr.nr, u64_to_user_ptr(rr.tags));
550 }
551 return -EINVAL;
552}
553
554int io_files_update_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
555{
556 struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update);
557
558 if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT)))
559 return -EINVAL;
560 if (sqe->rw_flags || sqe->splice_fd_in)
561 return -EINVAL;
562
563 up->offset = READ_ONCE(sqe->off);
564 up->nr_args = READ_ONCE(sqe->len);
565 if (!up->nr_args)
566 return -EINVAL;
567 up->arg = READ_ONCE(sqe->addr);
568 return 0;
569}
570
571static int io_files_update_with_index_alloc(struct io_kiocb *req,
572 unsigned int issue_flags)
573{
574 struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update);
575 __s32 __user *fds = u64_to_user_ptr(up->arg);
576 unsigned int done;
577 struct file *file;
578 int ret, fd;
579
580 if (!req->ctx->file_data)
581 return -ENXIO;
582
583 for (done = 0; done < up->nr_args; done++) {
584 if (copy_from_user(&fd, &fds[done], sizeof(fd))) {
585 ret = -EFAULT;
586 break;
587 }
588
589 file = fget(fd);
590 if (!file) {
591 ret = -EBADF;
592 break;
593 }
594 ret = io_fixed_fd_install(req, issue_flags, file,
595 IORING_FILE_INDEX_ALLOC);
596 if (ret < 0)
597 break;
598 if (copy_to_user(&fds[done], &ret, sizeof(ret))) {
599 __io_close_fixed(req->ctx, issue_flags, ret);
600 ret = -EFAULT;
601 break;
602 }
603 }
604
605 if (done)
606 return done;
607 return ret;
608}
609
610int io_files_update(struct io_kiocb *req, unsigned int issue_flags)
611{
612 struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update);
613 struct io_ring_ctx *ctx = req->ctx;
614 struct io_uring_rsrc_update2 up2;
615 int ret;
616
617 up2.offset = up->offset;
618 up2.data = up->arg;
619 up2.nr = 0;
620 up2.tags = 0;
621 up2.resv = 0;
622 up2.resv2 = 0;
623
624 if (up->offset == IORING_FILE_INDEX_ALLOC) {
625 ret = io_files_update_with_index_alloc(req, issue_flags);
626 } else {
627 io_ring_submit_lock(ctx, issue_flags);
628 ret = __io_register_rsrc_update(ctx, IORING_RSRC_FILE,
629 &up2, up->nr_args);
630 io_ring_submit_unlock(ctx, issue_flags);
631 }
632
633 if (ret < 0)
634 req_set_fail(req);
635 io_req_set_res(req, ret, 0);
636 return IOU_OK;
637}
638
639int io_queue_rsrc_removal(struct io_rsrc_data *data, unsigned idx, void *rsrc)
640{
641 struct io_ring_ctx *ctx = data->ctx;
642 struct io_rsrc_node *node = ctx->rsrc_node;
643 u64 *tag_slot = io_get_tag_slot(data, idx);
644
645 ctx->rsrc_node = io_rsrc_node_alloc(ctx);
646 if (unlikely(!ctx->rsrc_node)) {
647 ctx->rsrc_node = node;
648 return -ENOMEM;
649 }
650
651 node->item.rsrc = rsrc;
652 node->type = data->rsrc_type;
653 node->item.tag = *tag_slot;
654 *tag_slot = 0;
655 list_add_tail(&node->node, &ctx->rsrc_ref_list);
656 io_put_rsrc_node(ctx, node);
657 return 0;
658}
659
660void __io_sqe_files_unregister(struct io_ring_ctx *ctx)
661{
662 int i;
663
664 for (i = 0; i < ctx->nr_user_files; i++) {
665 struct file *file = io_file_from_index(&ctx->file_table, i);
666
667 if (!file)
668 continue;
669 io_file_bitmap_clear(&ctx->file_table, i);
670 fput(file);
671 }
672
673 io_free_file_tables(&ctx->file_table);
674 io_file_table_set_alloc_range(ctx, 0, 0);
675 io_rsrc_data_free(ctx->file_data);
676 ctx->file_data = NULL;
677 ctx->nr_user_files = 0;
678}
679
680int io_sqe_files_unregister(struct io_ring_ctx *ctx)
681{
682 unsigned nr = ctx->nr_user_files;
683 int ret;
684
685 if (!ctx->file_data)
686 return -ENXIO;
687
688 /*
689 * Quiesce may unlock ->uring_lock, and while it's not held
690 * prevent new requests using the table.
691 */
692 ctx->nr_user_files = 0;
693 ret = io_rsrc_ref_quiesce(ctx->file_data, ctx);
694 ctx->nr_user_files = nr;
695 if (!ret)
696 __io_sqe_files_unregister(ctx);
697 return ret;
698}
699
700int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
701 unsigned nr_args, u64 __user *tags)
702{
703 __s32 __user *fds = (__s32 __user *) arg;
704 struct file *file;
705 int fd, ret;
706 unsigned i;
707
708 if (ctx->file_data)
709 return -EBUSY;
710 if (!nr_args)
711 return -EINVAL;
712 if (nr_args > IORING_MAX_FIXED_FILES)
713 return -EMFILE;
714 if (nr_args > rlimit(RLIMIT_NOFILE))
715 return -EMFILE;
716 ret = io_rsrc_data_alloc(ctx, IORING_RSRC_FILE, tags, nr_args,
717 &ctx->file_data);
718 if (ret)
719 return ret;
720
721 if (!io_alloc_file_tables(&ctx->file_table, nr_args)) {
722 io_rsrc_data_free(ctx->file_data);
723 ctx->file_data = NULL;
724 return -ENOMEM;
725 }
726
727 for (i = 0; i < nr_args; i++, ctx->nr_user_files++) {
728 struct io_fixed_file *file_slot;
729
730 if (fds && copy_from_user(&fd, &fds[i], sizeof(fd))) {
731 ret = -EFAULT;
732 goto fail;
733 }
734 /* allow sparse sets */
735 if (!fds || fd == -1) {
736 ret = -EINVAL;
737 if (unlikely(*io_get_tag_slot(ctx->file_data, i)))
738 goto fail;
739 continue;
740 }
741
742 file = fget(fd);
743 ret = -EBADF;
744 if (unlikely(!file))
745 goto fail;
746
747 /*
748 * Don't allow io_uring instances to be registered.
749 */
750 if (io_is_uring_fops(file)) {
751 fput(file);
752 goto fail;
753 }
754 file_slot = io_fixed_file_slot(&ctx->file_table, i);
755 io_fixed_file_set(file_slot, file);
756 io_file_bitmap_set(&ctx->file_table, i);
757 }
758
759 /* default it to the whole table */
760 io_file_table_set_alloc_range(ctx, 0, ctx->nr_user_files);
761 return 0;
762fail:
763 __io_sqe_files_unregister(ctx);
764 return ret;
765}
766
767static void io_rsrc_buf_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc)
768{
769 io_buffer_unmap(ctx, &prsrc->buf);
770 prsrc->buf = NULL;
771}
772
773void __io_sqe_buffers_unregister(struct io_ring_ctx *ctx)
774{
775 unsigned int i;
776
777 for (i = 0; i < ctx->nr_user_bufs; i++)
778 io_buffer_unmap(ctx, &ctx->user_bufs[i]);
779 kfree(ctx->user_bufs);
780 io_rsrc_data_free(ctx->buf_data);
781 ctx->user_bufs = NULL;
782 ctx->buf_data = NULL;
783 ctx->nr_user_bufs = 0;
784}
785
786int io_sqe_buffers_unregister(struct io_ring_ctx *ctx)
787{
788 unsigned nr = ctx->nr_user_bufs;
789 int ret;
790
791 if (!ctx->buf_data)
792 return -ENXIO;
793
794 /*
795 * Quiesce may unlock ->uring_lock, and while it's not held
796 * prevent new requests using the table.
797 */
798 ctx->nr_user_bufs = 0;
799 ret = io_rsrc_ref_quiesce(ctx->buf_data, ctx);
800 ctx->nr_user_bufs = nr;
801 if (!ret)
802 __io_sqe_buffers_unregister(ctx);
803 return ret;
804}
805
806/*
807 * Not super efficient, but this is just a registration time. And we do cache
808 * the last compound head, so generally we'll only do a full search if we don't
809 * match that one.
810 *
811 * We check if the given compound head page has already been accounted, to
812 * avoid double accounting it. This allows us to account the full size of the
813 * page, not just the constituent pages of a huge page.
814 */
815static bool headpage_already_acct(struct io_ring_ctx *ctx, struct page **pages,
816 int nr_pages, struct page *hpage)
817{
818 int i, j;
819
820 /* check current page array */
821 for (i = 0; i < nr_pages; i++) {
822 if (!PageCompound(pages[i]))
823 continue;
824 if (compound_head(pages[i]) == hpage)
825 return true;
826 }
827
828 /* check previously registered pages */
829 for (i = 0; i < ctx->nr_user_bufs; i++) {
830 struct io_mapped_ubuf *imu = ctx->user_bufs[i];
831
832 for (j = 0; j < imu->nr_bvecs; j++) {
833 if (!PageCompound(imu->bvec[j].bv_page))
834 continue;
835 if (compound_head(imu->bvec[j].bv_page) == hpage)
836 return true;
837 }
838 }
839
840 return false;
841}
842
843static int io_buffer_account_pin(struct io_ring_ctx *ctx, struct page **pages,
844 int nr_pages, struct io_mapped_ubuf *imu,
845 struct page **last_hpage)
846{
847 int i, ret;
848
849 imu->acct_pages = 0;
850 for (i = 0; i < nr_pages; i++) {
851 if (!PageCompound(pages[i])) {
852 imu->acct_pages++;
853 } else {
854 struct page *hpage;
855
856 hpage = compound_head(pages[i]);
857 if (hpage == *last_hpage)
858 continue;
859 *last_hpage = hpage;
860 if (headpage_already_acct(ctx, pages, i, hpage))
861 continue;
862 imu->acct_pages += page_size(hpage) >> PAGE_SHIFT;
863 }
864 }
865
866 if (!imu->acct_pages)
867 return 0;
868
869 ret = io_account_mem(ctx, imu->acct_pages);
870 if (ret)
871 imu->acct_pages = 0;
872 return ret;
873}
874
875struct page **io_pin_pages(unsigned long ubuf, unsigned long len, int *npages)
876{
877 unsigned long start, end, nr_pages;
878 struct page **pages = NULL;
879 int ret;
880
881 end = (ubuf + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
882 start = ubuf >> PAGE_SHIFT;
883 nr_pages = end - start;
884 WARN_ON(!nr_pages);
885
886 pages = kvmalloc_array(nr_pages, sizeof(struct page *), GFP_KERNEL);
887 if (!pages)
888 return ERR_PTR(-ENOMEM);
889
890 mmap_read_lock(current->mm);
891 ret = pin_user_pages(ubuf, nr_pages, FOLL_WRITE | FOLL_LONGTERM, pages);
892 mmap_read_unlock(current->mm);
893
894 /* success, mapped all pages */
895 if (ret == nr_pages) {
896 *npages = nr_pages;
897 return pages;
898 }
899
900 /* partial map, or didn't map anything */
901 if (ret >= 0) {
902 /* if we did partial map, release any pages we did get */
903 if (ret)
904 unpin_user_pages(pages, ret);
905 ret = -EFAULT;
906 }
907 kvfree(pages);
908 return ERR_PTR(ret);
909}
910
911static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov,
912 struct io_mapped_ubuf **pimu,
913 struct page **last_hpage)
914{
915 struct io_mapped_ubuf *imu = NULL;
916 struct page **pages = NULL;
917 unsigned long off;
918 size_t size;
919 int ret, nr_pages, i;
920 struct folio *folio = NULL;
921
922 *pimu = (struct io_mapped_ubuf *)&dummy_ubuf;
923 if (!iov->iov_base)
924 return 0;
925
926 ret = -ENOMEM;
927 pages = io_pin_pages((unsigned long) iov->iov_base, iov->iov_len,
928 &nr_pages);
929 if (IS_ERR(pages)) {
930 ret = PTR_ERR(pages);
931 pages = NULL;
932 goto done;
933 }
934
935 /* If it's a huge page, try to coalesce them into a single bvec entry */
936 if (nr_pages > 1) {
937 folio = page_folio(pages[0]);
938 for (i = 1; i < nr_pages; i++) {
939 /*
940 * Pages must be consecutive and on the same folio for
941 * this to work
942 */
943 if (page_folio(pages[i]) != folio ||
944 pages[i] != pages[i - 1] + 1) {
945 folio = NULL;
946 break;
947 }
948 }
949 if (folio) {
950 /*
951 * The pages are bound to the folio, it doesn't
952 * actually unpin them but drops all but one reference,
953 * which is usually put down by io_buffer_unmap().
954 * Note, needs a better helper.
955 */
956 unpin_user_pages(&pages[1], nr_pages - 1);
957 nr_pages = 1;
958 }
959 }
960
961 imu = kvmalloc(struct_size(imu, bvec, nr_pages), GFP_KERNEL);
962 if (!imu)
963 goto done;
964
965 ret = io_buffer_account_pin(ctx, pages, nr_pages, imu, last_hpage);
966 if (ret) {
967 unpin_user_pages(pages, nr_pages);
968 goto done;
969 }
970
971 off = (unsigned long) iov->iov_base & ~PAGE_MASK;
972 size = iov->iov_len;
973 /* store original address for later verification */
974 imu->ubuf = (unsigned long) iov->iov_base;
975 imu->ubuf_end = imu->ubuf + iov->iov_len;
976 imu->nr_bvecs = nr_pages;
977 *pimu = imu;
978 ret = 0;
979
980 if (folio) {
981 bvec_set_page(&imu->bvec[0], pages[0], size, off);
982 goto done;
983 }
984 for (i = 0; i < nr_pages; i++) {
985 size_t vec_len;
986
987 vec_len = min_t(size_t, size, PAGE_SIZE - off);
988 bvec_set_page(&imu->bvec[i], pages[i], vec_len, off);
989 off = 0;
990 size -= vec_len;
991 }
992done:
993 if (ret)
994 kvfree(imu);
995 kvfree(pages);
996 return ret;
997}
998
999static int io_buffers_map_alloc(struct io_ring_ctx *ctx, unsigned int nr_args)
1000{
1001 ctx->user_bufs = kcalloc(nr_args, sizeof(*ctx->user_bufs), GFP_KERNEL);
1002 return ctx->user_bufs ? 0 : -ENOMEM;
1003}
1004
1005int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
1006 unsigned int nr_args, u64 __user *tags)
1007{
1008 struct page *last_hpage = NULL;
1009 struct io_rsrc_data *data;
1010 int i, ret;
1011 struct iovec iov;
1012
1013 BUILD_BUG_ON(IORING_MAX_REG_BUFFERS >= (1u << 16));
1014
1015 if (ctx->user_bufs)
1016 return -EBUSY;
1017 if (!nr_args || nr_args > IORING_MAX_REG_BUFFERS)
1018 return -EINVAL;
1019 ret = io_rsrc_data_alloc(ctx, IORING_RSRC_BUFFER, tags, nr_args, &data);
1020 if (ret)
1021 return ret;
1022 ret = io_buffers_map_alloc(ctx, nr_args);
1023 if (ret) {
1024 io_rsrc_data_free(data);
1025 return ret;
1026 }
1027
1028 for (i = 0; i < nr_args; i++, ctx->nr_user_bufs++) {
1029 if (arg) {
1030 ret = io_copy_iov(ctx, &iov, arg, i);
1031 if (ret)
1032 break;
1033 ret = io_buffer_validate(&iov);
1034 if (ret)
1035 break;
1036 } else {
1037 memset(&iov, 0, sizeof(iov));
1038 }
1039
1040 if (!iov.iov_base && *io_get_tag_slot(data, i)) {
1041 ret = -EINVAL;
1042 break;
1043 }
1044
1045 ret = io_sqe_buffer_register(ctx, &iov, &ctx->user_bufs[i],
1046 &last_hpage);
1047 if (ret)
1048 break;
1049 }
1050
1051 WARN_ON_ONCE(ctx->buf_data);
1052
1053 ctx->buf_data = data;
1054 if (ret)
1055 __io_sqe_buffers_unregister(ctx);
1056 return ret;
1057}
1058
1059int io_import_fixed(int ddir, struct iov_iter *iter,
1060 struct io_mapped_ubuf *imu,
1061 u64 buf_addr, size_t len)
1062{
1063 u64 buf_end;
1064 size_t offset;
1065
1066 if (WARN_ON_ONCE(!imu))
1067 return -EFAULT;
1068 if (unlikely(check_add_overflow(buf_addr, (u64)len, &buf_end)))
1069 return -EFAULT;
1070 /* not inside the mapped region */
1071 if (unlikely(buf_addr < imu->ubuf || buf_end > imu->ubuf_end))
1072 return -EFAULT;
1073
1074 /*
1075 * Might not be a start of buffer, set size appropriately
1076 * and advance us to the beginning.
1077 */
1078 offset = buf_addr - imu->ubuf;
1079 iov_iter_bvec(iter, ddir, imu->bvec, imu->nr_bvecs, offset + len);
1080
1081 if (offset) {
1082 /*
1083 * Don't use iov_iter_advance() here, as it's really slow for
1084 * using the latter parts of a big fixed buffer - it iterates
1085 * over each segment manually. We can cheat a bit here, because
1086 * we know that:
1087 *
1088 * 1) it's a BVEC iter, we set it up
1089 * 2) all bvecs are PAGE_SIZE in size, except potentially the
1090 * first and last bvec
1091 *
1092 * So just find our index, and adjust the iterator afterwards.
1093 * If the offset is within the first bvec (or the whole first
1094 * bvec, just use iov_iter_advance(). This makes it easier
1095 * since we can just skip the first segment, which may not
1096 * be PAGE_SIZE aligned.
1097 */
1098 const struct bio_vec *bvec = imu->bvec;
1099
1100 if (offset < bvec->bv_len) {
1101 /*
1102 * Note, huge pages buffers consists of one large
1103 * bvec entry and should always go this way. The other
1104 * branch doesn't expect non PAGE_SIZE'd chunks.
1105 */
1106 iter->bvec = bvec;
1107 iter->nr_segs = bvec->bv_len;
1108 iter->count -= offset;
1109 iter->iov_offset = offset;
1110 } else {
1111 unsigned long seg_skip;
1112
1113 /* skip first vec */
1114 offset -= bvec->bv_len;
1115 seg_skip = 1 + (offset >> PAGE_SHIFT);
1116
1117 iter->bvec = bvec + seg_skip;
1118 iter->nr_segs -= seg_skip;
1119 iter->count -= bvec->bv_len + offset;
1120 iter->iov_offset = offset & ~PAGE_MASK;
1121 }
1122 }
1123
1124 return 0;
1125}