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io_uring/rsrc: use nospec'ed indexes
[linux-block.git] / io_uring / rsrc.c
CommitLineData
73572984
JA		 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
73572984
JA		 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 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
73572984
JA		 30/* only define max */
31#define IORING_MAX_FIXED_FILES (1U << 20)
32#define IORING_MAX_REG_BUFFERS (1U << 14)
33
757ef468
PB		 34static inline bool io_put_rsrc_data_ref(struct io_rsrc_data *rsrc_data)
35{
36 return !--rsrc_data->refs;
37}
38
6a9ce66f 39int __io_account_mem(struct user_struct *user, unsigned long nr_pages)
73572984
JA		 40{
41 unsigned long page_limit, cur_pages, new_pages;
42
6a9ce66f
PB		 43 if (!nr_pages)
44 return 0;
45
73572984
JA		 46 /* Don't allow more pages than we can safely lock */
47 page_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
48
4ccc6db0 49 cur_pages = atomic_long_read(&user->locked_vm);
73572984 50 do {
73572984
JA		 51 new_pages = cur_pages + nr_pages;
52 if (new_pages > page_limit)
53 return -ENOMEM;
4ccc6db0
UB		 54 } while (!atomic_long_try_cmpxchg(&user->locked_vm,
55 &cur_pages, new_pages));
73572984
JA		 56 return 0;
57}
58
59static void io_unaccount_mem(struct io_ring_ctx *ctx, unsigned long nr_pages)
60{
61 if (ctx->user)
62 __io_unaccount_mem(ctx->user, nr_pages);
63
64 if (ctx->mm_account)
65 atomic64_sub(nr_pages, &ctx->mm_account->pinned_vm);
66}
67
68static int io_account_mem(struct io_ring_ctx *ctx, unsigned long nr_pages)
69{
70 int ret;
71
72 if (ctx->user) {
73 ret = __io_account_mem(ctx->user, nr_pages);
74 if (ret)
75 return ret;
76 }
77
78 if (ctx->mm_account)
79 atomic64_add(nr_pages, &ctx->mm_account->pinned_vm);
80
81 return 0;
82}
83
84static int io_copy_iov(struct io_ring_ctx *ctx, struct iovec *dst,
85 void __user *arg, unsigned index)
86{
87 struct iovec __user *src;
88
89#ifdef CONFIG_COMPAT
90 if (ctx->compat) {
91 struct compat_iovec __user *ciovs;
92 struct compat_iovec ciov;
93
94 ciovs = (struct compat_iovec __user *) arg;
95 if (copy_from_user(&ciov, &ciovs[index], sizeof(ciov)))
96 return -EFAULT;
97
98 dst->iov_base = u64_to_user_ptr((u64)ciov.iov_base);
99 dst->iov_len = ciov.iov_len;
100 return 0;
101 }
102#endif
103 src = (struct iovec __user *) arg;
104 if (copy_from_user(dst, &src[index], sizeof(*dst)))
105 return -EFAULT;
106 return 0;
107}
108
109static int io_buffer_validate(struct iovec *iov)
110{
111 unsigned long tmp, acct_len = iov->iov_len + (PAGE_SIZE - 1);
112
113 /*
114 * Don't impose further limits on the size and buffer
115 * constraints here, we'll -EINVAL later when IO is
116 * submitted if they are wrong.
117 */
118 if (!iov->iov_base)
119 return iov->iov_len ? -EFAULT : 0;
120 if (!iov->iov_len)
121 return -EFAULT;
122
123 /* arbitrary limit, but we need something */
124 if (iov->iov_len > SZ_1G)
125 return -EFAULT;
126
127 if (check_add_overflow((unsigned long)iov->iov_base, acct_len, &tmp))
128 return -EOVERFLOW;
129
130 return 0;
131}
132
133static void io_buffer_unmap(struct io_ring_ctx *ctx, struct io_mapped_ubuf **slot)
134{
135 struct io_mapped_ubuf *imu = *slot;
136 unsigned int i;
137
138 if (imu != ctx->dummy_ubuf) {
139 for (i = 0; i < imu->nr_bvecs; i++)
140 unpin_user_page(imu->bvec[i].bv_page);
141 if (imu->acct_pages)
142 io_unaccount_mem(ctx, imu->acct_pages);
143 kvfree(imu);
144 }
145 *slot = NULL;
146}
147
ff7c75ec
PB		 148static void io_rsrc_put_work_one(struct io_rsrc_data *rsrc_data,
149 struct io_rsrc_put *prsrc)
150{
151 struct io_ring_ctx *ctx = rsrc_data->ctx;
152
36b9818a
PB		 153 if (prsrc->tag)
154 io_post_aux_cqe(ctx, prsrc->tag, 0, 0);
ff7c75ec
PB		 155 rsrc_data->do_put(ctx, prsrc);
156}
157
73572984
JA		 158static void __io_rsrc_put_work(struct io_rsrc_node *ref_node)
159{
160 struct io_rsrc_data *rsrc_data = ref_node->rsrc_data;
73572984
JA		 161 struct io_rsrc_put *prsrc, *tmp;
162
ff7c75ec
PB		 163 if (ref_node->inline_items)
164 io_rsrc_put_work_one(rsrc_data, &ref_node->item);
165
c824986c 166 list_for_each_entry_safe(prsrc, tmp, &ref_node->item_list, list) {
73572984 167 list_del(&prsrc->list);
ff7c75ec 168 io_rsrc_put_work_one(rsrc_data, prsrc);
73572984
JA		 169 kfree(prsrc);
170 }
171
9eae8655 172 io_rsrc_node_destroy(rsrc_data->ctx, ref_node);
757ef468 173 if (io_put_rsrc_data_ref(rsrc_data))
73572984
JA		 174 complete(&rsrc_data->done);
175}
176
73572984
JA		 177void io_wait_rsrc_data(struct io_rsrc_data *data)
178{
757ef468 179 if (data && !io_put_rsrc_data_ref(data))
73572984
JA		 180 wait_for_completion(&data->done);
181}
182
9eae8655 183void io_rsrc_node_destroy(struct io_ring_ctx *ctx, struct io_rsrc_node *node)
73572984 184{
9eae8655
PB		 185 if (!io_alloc_cache_put(&ctx->rsrc_node_cache, &node->cache))
186 kfree(node);
73572984
JA		 187}
188
ef8ae64f
PB		 189void io_rsrc_node_ref_zero(struct io_rsrc_node *node)
190 __must_hold(&node->rsrc_data->ctx->uring_lock)
73572984 191{
73572984 192 struct io_ring_ctx *ctx = node->rsrc_data->ctx;
73572984 193
73572984 194 node->done = true;
73572984
JA		 195 while (!list_empty(&ctx->rsrc_ref_list)) {
196 node = list_first_entry(&ctx->rsrc_ref_list,
197 struct io_rsrc_node, node);
198 /* recycle ref nodes in order */
199 if (!node->done)
200 break;
73572984 201
36b9818a
PB		 202 list_del(&node->node);
203 __io_rsrc_put_work(node);
d34b1b0b 204 }
73572984
JA		 205}
206
2933ae6e 207struct io_rsrc_node *io_rsrc_node_alloc(struct io_ring_ctx *ctx)
73572984
JA		 208{
209 struct io_rsrc_node *ref_node;
9eae8655
PB		 210 struct io_cache_entry *entry;
211
212 entry = io_alloc_cache_get(&ctx->rsrc_node_cache);
213 if (entry) {
214 ref_node = container_of(entry, struct io_rsrc_node, cache);
215 } else {
216 ref_node = kzalloc(sizeof(*ref_node), GFP_KERNEL);
217 if (!ref_node)
218 return NULL;
219 }
73572984 220
13c22396 221 ref_node->rsrc_data = NULL;
ef8ae64f 222 ref_node->refs = 1;
73572984 223 INIT_LIST_HEAD(&ref_node->node);
c824986c 224 INIT_LIST_HEAD(&ref_node->item_list);
73572984 225 ref_node->done = false;
ff7c75ec 226 ref_node->inline_items = 0;
73572984
JA		 227 return ref_node;
228}
229
230void io_rsrc_node_switch(struct io_ring_ctx *ctx,
231 struct io_rsrc_data *data_to_kill)
232 __must_hold(&ctx->uring_lock)
233{
2933ae6e
PB		 234 struct io_rsrc_node *node = ctx->rsrc_node;
235 struct io_rsrc_node *backup = io_rsrc_node_alloc(ctx);
73572984 236
2933ae6e
PB		 237 if (WARN_ON_ONCE(!backup))
238 return;
73572984 239
2933ae6e
PB		 240 data_to_kill->refs++;
241 node->rsrc_data = data_to_kill;
242 list_add_tail(&node->node, &ctx->rsrc_ref_list);
243 /* put master ref */
244 io_put_rsrc_node(ctx, node);
245 ctx->rsrc_node = backup;
73572984
JA		 246}
247
248int io_rsrc_node_switch_start(struct io_ring_ctx *ctx)
249{
528407b1
PB		 250 if (io_alloc_cache_empty(&ctx->rsrc_node_cache)) {
251 struct io_rsrc_node *node = kzalloc(sizeof(*node), GFP_KERNEL);
252
253 if (!node)
254 return -ENOMEM;
255 io_alloc_cache_put(&ctx->rsrc_node_cache, &node->cache);
256 }
257 return 0;
73572984
JA		 258}
259
260__cold static int io_rsrc_ref_quiesce(struct io_rsrc_data *data,
261 struct io_ring_ctx *ctx)
262{
263 int ret;
264
265 /* As we may drop ->uring_lock, other task may have started quiesce */
266 if (data->quiesce)
267 return -ENXIO;
77e3202a
PB		 268 ret = io_rsrc_node_switch_start(ctx);
269 if (ret)
270 return ret;
271 io_rsrc_node_switch(ctx, data);
272
757ef468
PB		 273 /* kill initial ref */
274 if (io_put_rsrc_data_ref(data))
77e3202a 275 return 0;
73572984
JA		 276
277 data->quiesce = true;
77e3202a 278 mutex_unlock(&ctx->uring_lock);
73572984 279 do {
ef67fcb4 280 ret = io_run_task_work_sig(ctx);
77e3202a 281 if (ret < 0) {
77e3202a 282 mutex_lock(&ctx->uring_lock);
757ef468
PB		 283 if (!data->refs) {
284 ret = 0;
285 } else {
286 /* restore the master reference */
287 data->refs++;
288 }
77e3202a
PB		 289 break;
290 }
73572984
JA		 291 ret = wait_for_completion_interruptible(&data->done);
292 if (!ret) {
293 mutex_lock(&ctx->uring_lock);
757ef468 294 if (!data->refs)
73572984 295 break;
0ced756f
PB		 296 /*
297 * it has been revived by another thread while
298 * we were unlocked
299 */
300 mutex_unlock(&ctx->uring_lock);
73572984 301 }
77e3202a 302 } while (1);
73572984
JA		 303 data->quiesce = false;
304
305 return ret;
306}
307
308static void io_free_page_table(void **table, size_t size)
309{
310 unsigned i, nr_tables = DIV_ROUND_UP(size, PAGE_SIZE);
311
312 for (i = 0; i < nr_tables; i++)
313 kfree(table[i]);
314 kfree(table);
315}
316
317static void io_rsrc_data_free(struct io_rsrc_data *data)
318{
319 size_t size = data->nr * sizeof(data->tags[0][0]);
320
321 if (data->tags)
322 io_free_page_table((void **)data->tags, size);
323 kfree(data);
324}
325
326static __cold void **io_alloc_page_table(size_t size)
327{
328 unsigned i, nr_tables = DIV_ROUND_UP(size, PAGE_SIZE);
329 size_t init_size = size;
330 void **table;
331
332 table = kcalloc(nr_tables, sizeof(*table), GFP_KERNEL_ACCOUNT);
333 if (!table)
334 return NULL;
335
336 for (i = 0; i < nr_tables; i++) {
337 unsigned int this_size = min_t(size_t, size, PAGE_SIZE);
338
339 table[i] = kzalloc(this_size, GFP_KERNEL_ACCOUNT);
340 if (!table[i]) {
341 io_free_page_table(table, init_size);
342 return NULL;
343 }
344 size -= this_size;
345 }
346 return table;
347}
348
349__cold static int io_rsrc_data_alloc(struct io_ring_ctx *ctx,
350 rsrc_put_fn *do_put, u64 __user *utags,
351 unsigned nr, struct io_rsrc_data **pdata)
352{
353 struct io_rsrc_data *data;
6acd352d 354 int ret = 0;
73572984
JA		 355 unsigned i;
356
357 data = kzalloc(sizeof(*data), GFP_KERNEL);
358 if (!data)
359 return -ENOMEM;
360 data->tags = (u64 **)io_alloc_page_table(nr * sizeof(data->tags[0][0]));
361 if (!data->tags) {
362 kfree(data);
363 return -ENOMEM;
364 }
365
366 data->nr = nr;
367 data->ctx = ctx;
368 data->do_put = do_put;
757ef468 369 data->refs = 1;
73572984
JA		 370 if (utags) {
371 ret = -EFAULT;
372 for (i = 0; i < nr; i++) {
373 u64 *tag_slot = io_get_tag_slot(data, i);
374
375 if (copy_from_user(tag_slot, &utags[i],
376 sizeof(*tag_slot)))
377 goto fail;
378 }
379 }
73572984
JA		 380 init_completion(&data->done);
381 *pdata = data;
382 return 0;
383fail:
384 io_rsrc_data_free(data);
385 return ret;
386}
387
388static int __io_sqe_files_update(struct io_ring_ctx *ctx,
389 struct io_uring_rsrc_update2 *up,
390 unsigned nr_args)
391{
392 u64 __user *tags = u64_to_user_ptr(up->tags);
393 __s32 __user *fds = u64_to_user_ptr(up->data);
394 struct io_rsrc_data *data = ctx->file_data;
395 struct io_fixed_file *file_slot;
396 struct file *file;
397 int fd, i, err = 0;
398 unsigned int done;
399 bool needs_switch = false;
400
401 if (!ctx->file_data)
402 return -ENXIO;
403 if (up->offset + nr_args > ctx->nr_user_files)
404 return -EINVAL;
405
406 for (done = 0; done < nr_args; done++) {
407 u64 tag = 0;
408
409 if ((tags && copy_from_user(&tag, &tags[done], sizeof(tag))) ||
410 copy_from_user(&fd, &fds[done], sizeof(fd))) {
411 err = -EFAULT;
412 break;
413 }
414 if ((fd == IORING_REGISTER_FILES_SKIP || fd == -1) && tag) {
415 err = -EINVAL;
416 break;
417 }
418 if (fd == IORING_REGISTER_FILES_SKIP)
419 continue;
420
421 i = array_index_nospec(up->offset + done, ctx->nr_user_files);
422 file_slot = io_fixed_file_slot(&ctx->file_table, i);
423
424 if (file_slot->file_ptr) {
425 file = (struct file *)(file_slot->file_ptr & FFS_MASK);
426 err = io_queue_rsrc_removal(data, i, ctx->rsrc_node, file);
427 if (err)
428 break;
429 file_slot->file_ptr = 0;
430 io_file_bitmap_clear(&ctx->file_table, i);
431 needs_switch = true;
432 }
433 if (fd != -1) {
434 file = fget(fd);
435 if (!file) {
436 err = -EBADF;
437 break;
438 }
439 /*
440 * Don't allow io_uring instances to be registered. If
441 * UNIX isn't enabled, then this causes a reference
442 * cycle and this instance can never get freed. If UNIX
443 * is enabled we'll handle it just fine, but there's
444 * still no point in allowing a ring fd as it doesn't
445 * support regular read/write anyway.
446 */
447 if (io_is_uring_fops(file)) {
448 fput(file);
449 err = -EBADF;
450 break;
451 }
452 err = io_scm_file_account(ctx, file);
453 if (err) {
454 fput(file);
455 break;
456 }
457 *io_get_tag_slot(data, i) = tag;
458 io_fixed_file_set(file_slot, file);
459 io_file_bitmap_set(&ctx->file_table, i);
460 }
461 }
462
463 if (needs_switch)
464 io_rsrc_node_switch(ctx, data);
465 return done ? done : err;
466}
467
468static int __io_sqe_buffers_update(struct io_ring_ctx *ctx,
469 struct io_uring_rsrc_update2 *up,
470 unsigned int nr_args)
471{
472 u64 __user *tags = u64_to_user_ptr(up->tags);
473 struct iovec iov, __user *iovs = u64_to_user_ptr(up->data);
474 struct page *last_hpage = NULL;
475 bool needs_switch = false;
476 __u32 done;
477 int i, err;
478
479 if (!ctx->buf_data)
480 return -ENXIO;
481 if (up->offset + nr_args > ctx->nr_user_bufs)
482 return -EINVAL;
483
484 for (done = 0; done < nr_args; done++) {
485 struct io_mapped_ubuf *imu;
486 int offset = up->offset + done;
487 u64 tag = 0;
488
489 err = io_copy_iov(ctx, &iov, iovs, done);
490 if (err)
491 break;
492 if (tags && copy_from_user(&tag, &tags[done], sizeof(tag))) {
493 err = -EFAULT;
494 break;
495 }
496 err = io_buffer_validate(&iov);
497 if (err)
498 break;
499 if (!iov.iov_base && tag) {
500 err = -EINVAL;
501 break;
502 }
503 err = io_sqe_buffer_register(ctx, &iov, &imu, &last_hpage);
504 if (err)
505 break;
506
507 i = array_index_nospec(offset, ctx->nr_user_bufs);
508 if (ctx->user_bufs[i] != ctx->dummy_ubuf) {
509 err = io_queue_rsrc_removal(ctx->buf_data, i,
510 ctx->rsrc_node, ctx->user_bufs[i]);
511 if (unlikely(err)) {
512 io_buffer_unmap(ctx, &imu);
513 break;
514 }
5ff4fdff 515 ctx->user_bufs[i] = ctx->dummy_ubuf;
73572984
JA		 516 needs_switch = true;
517 }
518
519 ctx->user_bufs[i] = imu;
953c37e0 520 *io_get_tag_slot(ctx->buf_data, i) = tag;
73572984
JA		 521 }
522
523 if (needs_switch)
524 io_rsrc_node_switch(ctx, ctx->buf_data);
525 return done ? done : err;
526}
527
528static int __io_register_rsrc_update(struct io_ring_ctx *ctx, unsigned type,
529 struct io_uring_rsrc_update2 *up,
530 unsigned nr_args)
531{
532 __u32 tmp;
533 int err;
534
786788a8
PB		 535 lockdep_assert_held(&ctx->uring_lock);
536
73572984
JA		 537 if (check_add_overflow(up->offset, nr_args, &tmp))
538 return -EOVERFLOW;
539 err = io_rsrc_node_switch_start(ctx);
540 if (err)
541 return err;
542
543 switch (type) {
544 case IORING_RSRC_FILE:
545 return __io_sqe_files_update(ctx, up, nr_args);
546 case IORING_RSRC_BUFFER:
547 return __io_sqe_buffers_update(ctx, up, nr_args);
548 }
549 return -EINVAL;
550}
551
552int io_register_files_update(struct io_ring_ctx *ctx, void __user *arg,
553 unsigned nr_args)
554{
555 struct io_uring_rsrc_update2 up;
556
557 if (!nr_args)
558 return -EINVAL;
559 memset(&up, 0, sizeof(up));
560 if (copy_from_user(&up, arg, sizeof(struct io_uring_rsrc_update)))
561 return -EFAULT;
562 if (up.resv || up.resv2)
563 return -EINVAL;
564 return __io_register_rsrc_update(ctx, IORING_RSRC_FILE, &up, nr_args);
565}
566
567int io_register_rsrc_update(struct io_ring_ctx *ctx, void __user *arg,
568 unsigned size, unsigned type)
569{
570 struct io_uring_rsrc_update2 up;
571
572 if (size != sizeof(up))
573 return -EINVAL;
574 if (copy_from_user(&up, arg, sizeof(up)))
575 return -EFAULT;
576 if (!up.nr || up.resv || up.resv2)
577 return -EINVAL;
578 return __io_register_rsrc_update(ctx, type, &up, up.nr);
579}
580
581__cold int io_register_rsrc(struct io_ring_ctx *ctx, void __user *arg,
582 unsigned int size, unsigned int type)
583{
584 struct io_uring_rsrc_register rr;
585
586 /* keep it extendible */
587 if (size != sizeof(rr))
588 return -EINVAL;
589
590 memset(&rr, 0, sizeof(rr));
591 if (copy_from_user(&rr, arg, size))
592 return -EFAULT;
593 if (!rr.nr || rr.resv2)
594 return -EINVAL;
595 if (rr.flags & ~IORING_RSRC_REGISTER_SPARSE)
596 return -EINVAL;
597
598 switch (type) {
599 case IORING_RSRC_FILE:
600 if (rr.flags & IORING_RSRC_REGISTER_SPARSE && rr.data)
601 break;
602 return io_sqe_files_register(ctx, u64_to_user_ptr(rr.data),
603 rr.nr, u64_to_user_ptr(rr.tags));
604 case IORING_RSRC_BUFFER:
605 if (rr.flags & IORING_RSRC_REGISTER_SPARSE && rr.data)
606 break;
607 return io_sqe_buffers_register(ctx, u64_to_user_ptr(rr.data),
608 rr.nr, u64_to_user_ptr(rr.tags));
609 }
610 return -EINVAL;
611}
612
d9808ceb 613int io_files_update_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
73572984 614{
f2ccb5ae 615 struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update);
73572984
JA		 616
617 if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT)))
618 return -EINVAL;
619 if (sqe->rw_flags || sqe->splice_fd_in)
620 return -EINVAL;
621
622 up->offset = READ_ONCE(sqe->off);
623 up->nr_args = READ_ONCE(sqe->len);
624 if (!up->nr_args)
625 return -EINVAL;
626 up->arg = READ_ONCE(sqe->addr);
627 return 0;
628}
629
630static int io_files_update_with_index_alloc(struct io_kiocb *req,
631 unsigned int issue_flags)
632{
f2ccb5ae 633 struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update);
73572984
JA		 634 __s32 __user *fds = u64_to_user_ptr(up->arg);
635 unsigned int done;
636 struct file *file;
637 int ret, fd;
638
639 if (!req->ctx->file_data)
640 return -ENXIO;
641
642 for (done = 0; done < up->nr_args; done++) {
643 if (copy_from_user(&fd, &fds[done], sizeof(fd))) {
644 ret = -EFAULT;
645 break;
646 }
647
648 file = fget(fd);
649 if (!file) {
650 ret = -EBADF;
651 break;
652 }
653 ret = io_fixed_fd_install(req, issue_flags, file,
654 IORING_FILE_INDEX_ALLOC);
655 if (ret < 0)
656 break;
657 if (copy_to_user(&fds[done], &ret, sizeof(ret))) {
f110ed84 658 __io_close_fixed(req->ctx, issue_flags, ret);
73572984
JA		 659 ret = -EFAULT;
660 break;
661 }
662 }
663
664 if (done)
665 return done;
666 return ret;
667}
668
d9808ceb 669int io_files_update(struct io_kiocb *req, unsigned int issue_flags)
73572984 670{
f2ccb5ae 671 struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update);
73572984
JA		 672 struct io_ring_ctx *ctx = req->ctx;
673 struct io_uring_rsrc_update2 up2;
674 int ret;
675
676 up2.offset = up->offset;
677 up2.data = up->arg;
678 up2.nr = 0;
679 up2.tags = 0;
680 up2.resv = 0;
681 up2.resv2 = 0;
682
683 if (up->offset == IORING_FILE_INDEX_ALLOC) {
684 ret = io_files_update_with_index_alloc(req, issue_flags);
685 } else {
686 io_ring_submit_lock(ctx, issue_flags);
687 ret = __io_register_rsrc_update(ctx, IORING_RSRC_FILE,
688 &up2, up->nr_args);
689 io_ring_submit_unlock(ctx, issue_flags);
690 }
691
692 if (ret < 0)
693 req_set_fail(req);
694 io_req_set_res(req, ret, 0);
695 return IOU_OK;
696}
697
698int io_queue_rsrc_removal(struct io_rsrc_data *data, unsigned idx,
699 struct io_rsrc_node *node, void *rsrc)
700{
701 u64 *tag_slot = io_get_tag_slot(data, idx);
702 struct io_rsrc_put *prsrc;
ff7c75ec 703 bool inline_item = true;
73572984 704
ff7c75ec
PB		 705 if (!node->inline_items) {
706 prsrc = &node->item;
707 node->inline_items++;
708 } else {
709 prsrc = kzalloc(sizeof(*prsrc), GFP_KERNEL);
710 if (!prsrc)
711 return -ENOMEM;
712 inline_item = false;
713 }
73572984
JA		 714
715 prsrc->tag = *tag_slot;
716 *tag_slot = 0;
717 prsrc->rsrc = rsrc;
ff7c75ec
PB		 718 if (!inline_item)
719 list_add(&prsrc->list, &node->item_list);
73572984
JA		 720 return 0;
721}
722
723void __io_sqe_files_unregister(struct io_ring_ctx *ctx)
724{
73572984
JA		 725 int i;
726
727 for (i = 0; i < ctx->nr_user_files; i++) {
728 struct file *file = io_file_from_index(&ctx->file_table, i);
729
38eddb2c
PB		 730 /* skip scm accounted files, they'll be freed by ->ring_sock */
731 if (!file || io_file_need_scm(file))
73572984
JA		 732 continue;
733 io_file_bitmap_clear(&ctx->file_table, i);
734 fput(file);
735 }
73572984
JA		 736
737#if defined(CONFIG_UNIX)
738 if (ctx->ring_sock) {
739 struct sock *sock = ctx->ring_sock->sk;
740 struct sk_buff *skb;
741
742 while ((skb = skb_dequeue(&sock->sk_receive_queue)) != NULL)
743 kfree_skb(skb);
744 }
745#endif
746 io_free_file_tables(&ctx->file_table);
02a4d923 747 io_file_table_set_alloc_range(ctx, 0, 0);
73572984
JA		 748 io_rsrc_data_free(ctx->file_data);
749 ctx->file_data = NULL;
750 ctx->nr_user_files = 0;
751}
752
753int io_sqe_files_unregister(struct io_ring_ctx *ctx)
754{
755 unsigned nr = ctx->nr_user_files;
756 int ret;
757
758 if (!ctx->file_data)
759 return -ENXIO;
760
761 /*
762 * Quiesce may unlock ->uring_lock, and while it's not held
763 * prevent new requests using the table.
764 */
765 ctx->nr_user_files = 0;
766 ret = io_rsrc_ref_quiesce(ctx->file_data, ctx);
767 ctx->nr_user_files = nr;
768 if (!ret)
769 __io_sqe_files_unregister(ctx);
770 return ret;
771}
772
773/*
774 * Ensure the UNIX gc is aware of our file set, so we are certain that
775 * the io_uring can be safely unregistered on process exit, even if we have
776 * loops in the file referencing. We account only files that can hold other
777 * files because otherwise they can't form a loop and so are not interesting
778 * for GC.
779 */
780int __io_scm_file_account(struct io_ring_ctx *ctx, struct file *file)
781{
782#if defined(CONFIG_UNIX)
783 struct sock *sk = ctx->ring_sock->sk;
784 struct sk_buff_head *head = &sk->sk_receive_queue;
785 struct scm_fp_list *fpl;
786 struct sk_buff *skb;
787
788 if (likely(!io_file_need_scm(file)))
789 return 0;
790
791 /*
792 * See if we can merge this file into an existing skb SCM_RIGHTS
793 * file set. If there's no room, fall back to allocating a new skb
794 * and filling it in.
795 */
796 spin_lock_irq(&head->lock);
797 skb = skb_peek(head);
798 if (skb && UNIXCB(skb).fp->count < SCM_MAX_FD)
799 __skb_unlink(skb, head);
800 else
801 skb = NULL;
802 spin_unlock_irq(&head->lock);
803
804 if (!skb) {
805 fpl = kzalloc(sizeof(*fpl), GFP_KERNEL);
806 if (!fpl)
807 return -ENOMEM;
808
809 skb = alloc_skb(0, GFP_KERNEL);
810 if (!skb) {
811 kfree(fpl);
812 return -ENOMEM;
813 }
814
815 fpl->user = get_uid(current_user());
816 fpl->max = SCM_MAX_FD;
817 fpl->count = 0;
818
819 UNIXCB(skb).fp = fpl;
820 skb->sk = sk;
0091bfc8 821 skb->scm_io_uring = 1;
73572984
JA		 822 skb->destructor = unix_destruct_scm;
823 refcount_add(skb->truesize, &sk->sk_wmem_alloc);
824 }
825
826 fpl = UNIXCB(skb).fp;
827 fpl->fp[fpl->count++] = get_file(file);
828 unix_inflight(fpl->user, file);
829 skb_queue_head(head, skb);
830 fput(file);
831#endif
832 return 0;
833}
834
d581076b 835static __cold void io_rsrc_file_scm_put(struct io_ring_ctx *ctx, struct file *file)
73572984 836{
73572984
JA		 837#if defined(CONFIG_UNIX)
838 struct sock *sock = ctx->ring_sock->sk;
839 struct sk_buff_head list, *head = &sock->sk_receive_queue;
840 struct sk_buff *skb;
841 int i;
842
73572984
JA		 843 __skb_queue_head_init(&list);
844
845 /*
846 * Find the skb that holds this file in its SCM_RIGHTS. When found,
847 * remove this entry and rearrange the file array.
848 */
849 skb = skb_dequeue(head);
850 while (skb) {
851 struct scm_fp_list *fp;
852
853 fp = UNIXCB(skb).fp;
854 for (i = 0; i < fp->count; i++) {
855 int left;
856
857 if (fp->fp[i] != file)
858 continue;
859
860 unix_notinflight(fp->user, fp->fp[i]);
861 left = fp->count - 1 - i;
862 if (left) {
863 memmove(&fp->fp[i], &fp->fp[i + 1],
864 left * sizeof(struct file *));
865 }
866 fp->count--;
867 if (!fp->count) {
868 kfree_skb(skb);
869 skb = NULL;
870 } else {
871 __skb_queue_tail(&list, skb);
872 }
873 fput(file);
874 file = NULL;
875 break;
876 }
877
878 if (!file)
879 break;
880
881 __skb_queue_tail(&list, skb);
882
883 skb = skb_dequeue(head);
884 }
885
886 if (skb_peek(&list)) {
887 spin_lock_irq(&head->lock);
888 while ((skb = __skb_dequeue(&list)) != NULL)
889 __skb_queue_tail(head, skb);
890 spin_unlock_irq(&head->lock);
891 }
73572984
JA		 892#endif
893}
894
d581076b
PB		 895static void io_rsrc_file_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc)
896{
897 struct file *file = prsrc->file;
898
899 if (likely(!io_file_need_scm(file)))
900 fput(file);
901 else
902 io_rsrc_file_scm_put(ctx, file);
903}
904
73572984
JA		 905int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
906 unsigned nr_args, u64 __user *tags)
907{
908 __s32 __user *fds = (__s32 __user *) arg;
909 struct file *file;
910 int fd, ret;
911 unsigned i;
912
913 if (ctx->file_data)
914 return -EBUSY;
915 if (!nr_args)
916 return -EINVAL;
917 if (nr_args > IORING_MAX_FIXED_FILES)
918 return -EMFILE;
919 if (nr_args > rlimit(RLIMIT_NOFILE))
920 return -EMFILE;
73572984
JA		 921 ret = io_rsrc_data_alloc(ctx, io_rsrc_file_put, tags, nr_args,
922 &ctx->file_data);
923 if (ret)
924 return ret;
925
926 if (!io_alloc_file_tables(&ctx->file_table, nr_args)) {
927 io_rsrc_data_free(ctx->file_data);
928 ctx->file_data = NULL;
929 return -ENOMEM;
930 }
931
932 for (i = 0; i < nr_args; i++, ctx->nr_user_files++) {
933 struct io_fixed_file *file_slot;
934
935 if (fds && copy_from_user(&fd, &fds[i], sizeof(fd))) {
936 ret = -EFAULT;
937 goto fail;
938 }
939 /* allow sparse sets */
940 if (!fds || fd == -1) {
941 ret = -EINVAL;
942 if (unlikely(*io_get_tag_slot(ctx->file_data, i)))
943 goto fail;
944 continue;
945 }
946
947 file = fget(fd);
948 ret = -EBADF;
949 if (unlikely(!file))
950 goto fail;
951
952 /*
953 * Don't allow io_uring instances to be registered. If UNIX
954 * isn't enabled, then this causes a reference cycle and this
955 * instance can never get freed. If UNIX is enabled we'll
956 * handle it just fine, but there's still no point in allowing
957 * a ring fd as it doesn't support regular read/write anyway.
958 */
959 if (io_is_uring_fops(file)) {
960 fput(file);
961 goto fail;
962 }
963 ret = io_scm_file_account(ctx, file);
964 if (ret) {
965 fput(file);
966 goto fail;
967 }
968 file_slot = io_fixed_file_slot(&ctx->file_table, i);
969 io_fixed_file_set(file_slot, file);
970 io_file_bitmap_set(&ctx->file_table, i);
971 }
972
6e73dffb
PB		 973 /* default it to the whole table */
974 io_file_table_set_alloc_range(ctx, 0, ctx->nr_user_files);
73572984
JA		 975 return 0;
976fail:
977 __io_sqe_files_unregister(ctx);
978 return ret;
979}
980
981static void io_rsrc_buf_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc)
982{
983 io_buffer_unmap(ctx, &prsrc->buf);
984 prsrc->buf = NULL;
985}
986
987void __io_sqe_buffers_unregister(struct io_ring_ctx *ctx)
988{
989 unsigned int i;
990
991 for (i = 0; i < ctx->nr_user_bufs; i++)
992 io_buffer_unmap(ctx, &ctx->user_bufs[i]);
993 kfree(ctx->user_bufs);
994 io_rsrc_data_free(ctx->buf_data);
995 ctx->user_bufs = NULL;
996 ctx->buf_data = NULL;
997 ctx->nr_user_bufs = 0;
998}
999
1000int io_sqe_buffers_unregister(struct io_ring_ctx *ctx)
1001{
1002 unsigned nr = ctx->nr_user_bufs;
1003 int ret;
1004
1005 if (!ctx->buf_data)
1006 return -ENXIO;
1007
1008 /*
1009 * Quiesce may unlock ->uring_lock, and while it's not held
1010 * prevent new requests using the table.
1011 */
1012 ctx->nr_user_bufs = 0;
1013 ret = io_rsrc_ref_quiesce(ctx->buf_data, ctx);
1014 ctx->nr_user_bufs = nr;
1015 if (!ret)
1016 __io_sqe_buffers_unregister(ctx);
1017 return ret;
1018}
1019
1020/*
1021 * Not super efficient, but this is just a registration time. And we do cache
1022 * the last compound head, so generally we'll only do a full search if we don't
1023 * match that one.
1024 *
1025 * We check if the given compound head page has already been accounted, to
1026 * avoid double accounting it. This allows us to account the full size of the
1027 * page, not just the constituent pages of a huge page.
1028 */
1029static bool headpage_already_acct(struct io_ring_ctx *ctx, struct page **pages,
1030 int nr_pages, struct page *hpage)
1031{
1032 int i, j;
1033
1034 /* check current page array */
1035 for (i = 0; i < nr_pages; i++) {
1036 if (!PageCompound(pages[i]))
1037 continue;
1038 if (compound_head(pages[i]) == hpage)
1039 return true;
1040 }
1041
1042 /* check previously registered pages */
1043 for (i = 0; i < ctx->nr_user_bufs; i++) {
1044 struct io_mapped_ubuf *imu = ctx->user_bufs[i];
1045
1046 for (j = 0; j < imu->nr_bvecs; j++) {
1047 if (!PageCompound(imu->bvec[j].bv_page))
1048 continue;
1049 if (compound_head(imu->bvec[j].bv_page) == hpage)
1050 return true;
1051 }
1052 }
1053
1054 return false;
1055}
1056
1057static int io_buffer_account_pin(struct io_ring_ctx *ctx, struct page **pages,
1058 int nr_pages, struct io_mapped_ubuf *imu,
1059 struct page **last_hpage)
1060{
1061 int i, ret;
1062
1063 imu->acct_pages = 0;
1064 for (i = 0; i < nr_pages; i++) {
1065 if (!PageCompound(pages[i])) {
1066 imu->acct_pages++;
1067 } else {
1068 struct page *hpage;
1069
1070 hpage = compound_head(pages[i]);
1071 if (hpage == *last_hpage)
1072 continue;
1073 *last_hpage = hpage;
1074 if (headpage_already_acct(ctx, pages, i, hpage))
1075 continue;
1076 imu->acct_pages += page_size(hpage) >> PAGE_SHIFT;
1077 }
1078 }
1079
1080 if (!imu->acct_pages)
1081 return 0;
1082
1083 ret = io_account_mem(ctx, imu->acct_pages);
1084 if (ret)
1085 imu->acct_pages = 0;
1086 return ret;
1087}
1088
1089struct page **io_pin_pages(unsigned long ubuf, unsigned long len, int *npages)
1090{
1091 unsigned long start, end, nr_pages;
1092 struct vm_area_struct **vmas = NULL;
1093 struct page **pages = NULL;
1094 int i, pret, ret = -ENOMEM;
1095
1096 end = (ubuf + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1097 start = ubuf >> PAGE_SHIFT;
1098 nr_pages = end - start;
1099
1100 pages = kvmalloc_array(nr_pages, sizeof(struct page *), GFP_KERNEL);
1101 if (!pages)
1102 goto done;
1103
1104 vmas = kvmalloc_array(nr_pages, sizeof(struct vm_area_struct *),
1105 GFP_KERNEL);
1106 if (!vmas)
1107 goto done;
1108
1109 ret = 0;
1110 mmap_read_lock(current->mm);
1111 pret = pin_user_pages(ubuf, nr_pages, FOLL_WRITE | FOLL_LONGTERM,
1112 pages, vmas);
1113 if (pret == nr_pages) {
edd47826
PB		 1114 struct file *file = vmas[0]->vm_file;
1115
73572984
JA		 1116 /* don't support file backed memory */
1117 for (i = 0; i < nr_pages; i++) {
edd47826
PB		 1118 if (vmas[i]->vm_file != file) {
1119 ret = -EINVAL;
1120 break;
1121 }
1122 if (!file)
73572984 1123 continue;
edd47826 1124 if (!vma_is_shmem(vmas[i]) && !is_file_hugepages(file)) {
73572984
JA		 1125 ret = -EOPNOTSUPP;
1126 break;
1127 }
1128 }
1129 *npages = nr_pages;
1130 } else {
1131 ret = pret < 0 ? pret : -EFAULT;
1132 }
1133 mmap_read_unlock(current->mm);
1134 if (ret) {
1135 /*
1136 * if we did partial map, or found file backed vmas,
1137 * release any pages we did get
1138 */
1139 if (pret > 0)
1140 unpin_user_pages(pages, pret);
1141 goto done;
1142 }
1143 ret = 0;
1144done:
1145 kvfree(vmas);
1146 if (ret < 0) {
1147 kvfree(pages);
1148 pages = ERR_PTR(ret);
1149 }
1150 return pages;
1151}
1152
1153static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov,
1154 struct io_mapped_ubuf **pimu,
1155 struct page **last_hpage)
1156{
1157 struct io_mapped_ubuf *imu = NULL;
1158 struct page **pages = NULL;
1159 unsigned long off;
1160 size_t size;
1161 int ret, nr_pages, i;
977bc873 1162 struct folio *folio = NULL;
73572984 1163
5ff4fdff
PB		 1164 *pimu = ctx->dummy_ubuf;
1165 if (!iov->iov_base)
73572984 1166 return 0;
73572984 1167
73572984 1168 ret = -ENOMEM;
73572984
JA		 1169 pages = io_pin_pages((unsigned long) iov->iov_base, iov->iov_len,
1170 &nr_pages);
1171 if (IS_ERR(pages)) {
1172 ret = PTR_ERR(pages);
1173 pages = NULL;
1174 goto done;
1175 }
1176
57bebf80
PB		 1177 /* If it's a huge page, try to coalesce them into a single bvec entry */
1178 if (nr_pages > 1) {
1179 folio = page_folio(pages[0]);
1180 for (i = 1; i < nr_pages; i++) {
1181 if (page_folio(pages[i]) != folio) {
1182 folio = NULL;
1183 break;
1184 }
1185 }
1186 if (folio) {
d2acf789
PB		 1187 /*
1188 * The pages are bound to the folio, it doesn't
1189 * actually unpin them but drops all but one reference,
1190 * which is usually put down by io_buffer_unmap().
1191 * Note, needs a better helper.
1192 */
1193 unpin_user_pages(&pages[1], nr_pages - 1);
57bebf80
PB		 1194 nr_pages = 1;
1195 }
1196 }
1197
73572984
JA		 1198 imu = kvmalloc(struct_size(imu, bvec, nr_pages), GFP_KERNEL);
1199 if (!imu)
1200 goto done;
1201
1202 ret = io_buffer_account_pin(ctx, pages, nr_pages, imu, last_hpage);
1203 if (ret) {
1204 unpin_user_pages(pages, nr_pages);
1205 goto done;
1206 }
1207
1208 off = (unsigned long) iov->iov_base & ~PAGE_MASK;
1209 size = iov->iov_len;
57bebf80
PB		 1210 /* store original address for later verification */
1211 imu->ubuf = (unsigned long) iov->iov_base;
1212 imu->ubuf_end = imu->ubuf + iov->iov_len;
1213 imu->nr_bvecs = nr_pages;
1214 *pimu = imu;
1215 ret = 0;
1216
1217 if (folio) {
1218 bvec_set_page(&imu->bvec[0], pages[0], size, off);
1219 goto done;
1220 }
73572984
JA		 1221 for (i = 0; i < nr_pages; i++) {
1222 size_t vec_len;
1223
1224 vec_len = min_t(size_t, size, PAGE_SIZE - off);
cc342a21 1225 bvec_set_page(&imu->bvec[i], pages[i], vec_len, off);
73572984
JA		 1226 off = 0;
1227 size -= vec_len;
1228 }
73572984
JA		 1229done:
1230 if (ret)
1231 kvfree(imu);
1232 kvfree(pages);
1233 return ret;
1234}
1235
1236static int io_buffers_map_alloc(struct io_ring_ctx *ctx, unsigned int nr_args)
1237{
1238 ctx->user_bufs = kcalloc(nr_args, sizeof(*ctx->user_bufs), GFP_KERNEL);
1239 return ctx->user_bufs ? 0 : -ENOMEM;
1240}
1241
1242int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
1243 unsigned int nr_args, u64 __user *tags)
1244{
1245 struct page *last_hpage = NULL;
1246 struct io_rsrc_data *data;
1247 int i, ret;
1248 struct iovec iov;
1249
1250 BUILD_BUG_ON(IORING_MAX_REG_BUFFERS >= (1u << 16));
1251
1252 if (ctx->user_bufs)
1253 return -EBUSY;
1254 if (!nr_args || nr_args > IORING_MAX_REG_BUFFERS)
1255 return -EINVAL;
73572984
JA		 1256 ret = io_rsrc_data_alloc(ctx, io_rsrc_buf_put, tags, nr_args, &data);
1257 if (ret)
1258 return ret;
1259 ret = io_buffers_map_alloc(ctx, nr_args);
1260 if (ret) {
1261 io_rsrc_data_free(data);
1262 return ret;
1263 }
1264
1265 for (i = 0; i < nr_args; i++, ctx->nr_user_bufs++) {
1266 if (arg) {
1267 ret = io_copy_iov(ctx, &iov, arg, i);
1268 if (ret)
1269 break;
1270 ret = io_buffer_validate(&iov);
1271 if (ret)
1272 break;
1273 } else {
1274 memset(&iov, 0, sizeof(iov));
1275 }
1276
1277 if (!iov.iov_base && *io_get_tag_slot(data, i)) {
1278 ret = -EINVAL;
1279 break;
1280 }
1281
1282 ret = io_sqe_buffer_register(ctx, &iov, &ctx->user_bufs[i],
1283 &last_hpage);
1284 if (ret)
1285 break;
1286 }
1287
1288 WARN_ON_ONCE(ctx->buf_data);
1289
1290 ctx->buf_data = data;
1291 if (ret)
1292 __io_sqe_buffers_unregister(ctx);
73572984
JA		 1293 return ret;
1294}
c059f785
PB		 1295
1296int io_import_fixed(int ddir, struct iov_iter *iter,
1297 struct io_mapped_ubuf *imu,
1298 u64 buf_addr, size_t len)
1299{
1300 u64 buf_end;
1301 size_t offset;
1302
1303 if (WARN_ON_ONCE(!imu))
1304 return -EFAULT;
1305 if (unlikely(check_add_overflow(buf_addr, (u64)len, &buf_end)))
1306 return -EFAULT;
1307 /* not inside the mapped region */
1308 if (unlikely(buf_addr < imu->ubuf || buf_end > imu->ubuf_end))
1309 return -EFAULT;
1310
1311 /*
6bf65a1b 1312 * Might not be a start of buffer, set size appropriately
c059f785
PB		 1313 * and advance us to the beginning.
1314 */
1315 offset = buf_addr - imu->ubuf;
1316 iov_iter_bvec(iter, ddir, imu->bvec, imu->nr_bvecs, offset + len);
1317
1318 if (offset) {
1319 /*
1320 * Don't use iov_iter_advance() here, as it's really slow for
1321 * using the latter parts of a big fixed buffer - it iterates
1322 * over each segment manually. We can cheat a bit here, because
1323 * we know that:
1324 *
1325 * 1) it's a BVEC iter, we set it up
1326 * 2) all bvecs are PAGE_SIZE in size, except potentially the
1327 * first and last bvec
1328 *
1329 * So just find our index, and adjust the iterator afterwards.
1330 * If the offset is within the first bvec (or the whole first
1331 * bvec, just use iov_iter_advance(). This makes it easier
1332 * since we can just skip the first segment, which may not
1333 * be PAGE_SIZE aligned.
1334 */
1335 const struct bio_vec *bvec = imu->bvec;
1336
1337 if (offset <= bvec->bv_len) {
57bebf80
PB		 1338 /*
1339 * Note, huge pages buffers consists of one large
1340 * bvec entry and should always go this way. The other
1341 * branch doesn't expect non PAGE_SIZE'd chunks.
1342 */
b000ae0e
PB		 1343 iter->bvec = bvec;
1344 iter->nr_segs = bvec->bv_len;
1345 iter->count -= offset;
1346 iter->iov_offset = offset;
c059f785
PB		 1347 } else {
1348 unsigned long seg_skip;
1349
1350 /* skip first vec */
1351 offset -= bvec->bv_len;
1352 seg_skip = 1 + (offset >> PAGE_SHIFT);
1353
1354 iter->bvec = bvec + seg_skip;
1355 iter->nr_segs -= seg_skip;
1356 iter->count -= bvec->bv_len + offset;
1357 iter->iov_offset = offset & ~PAGE_MASK;
1358 }
1359 }
1360
1361 return 0;
1362}
Linux 6.x block layer and io_uring tree(s)