Repository navigation
Expand file tree
/
Copy pathnstree.c
More file actions
786 lines (646 loc) · 18.3 KB
/
Copy pathnstree.c
File metadata and controls
786 lines (646 loc) · 18.3 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2025 Christian Brauner <brauner@kernel.org> */
#include <linux/nstree.h>
#include <linux/proc_ns.h>
#include <linux/rculist.h>
#include <linux/vfsdebug.h>
#include <linux/syscalls.h>
#include <linux/user_namespace.h>
static __cacheline_aligned_in_smp DEFINE_SEQLOCK(ns_tree_lock);
DEFINE_LOCK_GUARD_0(ns_tree_writer,
write_seqlock(&ns_tree_lock),
write_sequnlock(&ns_tree_lock))
DEFINE_LOCK_GUARD_0(ns_tree_locked_reader,
read_seqlock_excl(&ns_tree_lock),
read_sequnlock_excl(&ns_tree_lock))
static struct ns_tree_root ns_unified_root = { /* protected by ns_tree_lock */
.ns_rb = RB_ROOT,
.ns_list_head = LIST_HEAD_INIT(ns_unified_root.ns_list_head),
};
struct ns_tree_root mnt_ns_tree = {
.ns_rb = RB_ROOT,
.ns_list_head = LIST_HEAD_INIT(mnt_ns_tree.ns_list_head),
};
struct ns_tree_root net_ns_tree = {
.ns_rb = RB_ROOT,
.ns_list_head = LIST_HEAD_INIT(net_ns_tree.ns_list_head),
};
EXPORT_SYMBOL_GPL(net_ns_tree);
struct ns_tree_root uts_ns_tree = {
.ns_rb = RB_ROOT,
.ns_list_head = LIST_HEAD_INIT(uts_ns_tree.ns_list_head),
};
struct ns_tree_root user_ns_tree = {
.ns_rb = RB_ROOT,
.ns_list_head = LIST_HEAD_INIT(user_ns_tree.ns_list_head),
};
struct ns_tree_root ipc_ns_tree = {
.ns_rb = RB_ROOT,
.ns_list_head = LIST_HEAD_INIT(ipc_ns_tree.ns_list_head),
};
struct ns_tree_root pid_ns_tree = {
.ns_rb = RB_ROOT,
.ns_list_head = LIST_HEAD_INIT(pid_ns_tree.ns_list_head),
};
struct ns_tree_root cgroup_ns_tree = {
.ns_rb = RB_ROOT,
.ns_list_head = LIST_HEAD_INIT(cgroup_ns_tree.ns_list_head),
};
struct ns_tree_root time_ns_tree = {
.ns_rb = RB_ROOT,
.ns_list_head = LIST_HEAD_INIT(time_ns_tree.ns_list_head),
};
/**
* ns_tree_node_init - Initialize a namespace tree node
* @node: The node to initialize
*
* Initializes both the rbtree node and list entry.
*/
void ns_tree_node_init(struct ns_tree_node *node)
{
RB_CLEAR_NODE(&node->ns_node);
INIT_LIST_HEAD(&node->ns_list_entry);
}
/**
* ns_tree_root_init - Initialize a namespace tree root
* @root: The root to initialize
*
* Initializes both the rbtree root and list head.
*/
void ns_tree_root_init(struct ns_tree_root *root)
{
root->ns_rb = RB_ROOT;
INIT_LIST_HEAD(&root->ns_list_head);
}
/**
* ns_tree_node_empty - Check if a namespace tree node is empty
* @node: The node to check
*
* Returns true if the node is not in any tree.
*/
bool ns_tree_node_empty(const struct ns_tree_node *node)
{
return RB_EMPTY_NODE(&node->ns_node);
}
/**
* ns_tree_node_add - Add a node to a namespace tree
* @node: The node to add
* @root: The tree root to add to
* @cmp: Comparison function for rbtree insertion
*
* Adds the node to both the rbtree and the list, maintaining sorted order.
* The list is maintained in the same order as the rbtree to enable efficient
* iteration.
*
* Returns: NULL if insertion succeeded, existing node if duplicate found
*/
struct rb_node *ns_tree_node_add(struct ns_tree_node *node,
struct ns_tree_root *root,
int (*cmp)(struct rb_node *, const struct rb_node *))
{
struct rb_node *ret, *prev;
/* Add to rbtree */
ret = rb_find_add_rcu(&node->ns_node, &root->ns_rb, cmp);
/* Add to list in sorted order */
prev = rb_prev(&node->ns_node);
if (!prev) {
/* No previous node, add at head */
list_add_rcu(&node->ns_list_entry, &root->ns_list_head);
} else {
/* Add after previous node */
struct ns_tree_node *prev_node;
prev_node = rb_entry(prev, struct ns_tree_node, ns_node);
list_add_rcu(&node->ns_list_entry, &prev_node->ns_list_entry);
}
return ret;
}
/**
* ns_tree_node_del - Remove a node from a namespace tree
* @node: The node to remove
* @root: The tree root to remove from
*
* Removes the node from both the rbtree and the list atomically.
*/
void ns_tree_node_del(struct ns_tree_node *node, struct ns_tree_root *root)
{
rb_erase(&node->ns_node, &root->ns_rb);
RB_CLEAR_NODE(&node->ns_node);
list_bidir_del_rcu(&node->ns_list_entry);
}
static inline struct ns_common *node_to_ns(const struct rb_node *node)
{
if (!node)
return NULL;
return rb_entry(node, struct ns_common, ns_tree_node.ns_node);
}
static inline struct ns_common *node_to_ns_unified(const struct rb_node *node)
{
if (!node)
return NULL;
return rb_entry(node, struct ns_common, ns_unified_node.ns_node);
}
static inline struct ns_common *node_to_ns_owner(const struct rb_node *node)
{
if (!node)
return NULL;
return rb_entry(node, struct ns_common, ns_owner_node.ns_node);
}
static int ns_id_cmp(u64 id_a, u64 id_b)
{
if (id_a < id_b)
return -1;
if (id_a > id_b)
return 1;
return 0;
}
static int ns_cmp(struct rb_node *a, const struct rb_node *b)
{
return ns_id_cmp(node_to_ns(a)->ns_id, node_to_ns(b)->ns_id);
}
static int ns_cmp_unified(struct rb_node *a, const struct rb_node *b)
{
return ns_id_cmp(node_to_ns_unified(a)->ns_id, node_to_ns_unified(b)->ns_id);
}
static int ns_cmp_owner(struct rb_node *a, const struct rb_node *b)
{
return ns_id_cmp(node_to_ns_owner(a)->ns_id, node_to_ns_owner(b)->ns_id);
}
void __ns_tree_add_raw(struct ns_common *ns, struct ns_tree_root *ns_tree)
{
struct rb_node *node;
const struct proc_ns_operations *ops = ns->ops;
VFS_WARN_ON_ONCE(!ns->ns_id);
guard(ns_tree_writer)();
/* Add to per-type tree and list */
node = ns_tree_node_add(&ns->ns_tree_node, ns_tree, ns_cmp);
/* Add to unified tree and list */
ns_tree_node_add(&ns->ns_unified_node, &ns_unified_root, ns_cmp_unified);
/* Add to owner's tree if applicable */
if (ops) {
struct user_namespace *user_ns;
VFS_WARN_ON_ONCE(!ops->owner);
user_ns = ops->owner(ns);
if (user_ns) {
struct ns_common *owner = &user_ns->ns;
VFS_WARN_ON_ONCE(owner->ns_type != CLONE_NEWUSER);
/* Insert into owner's tree and list */
ns_tree_node_add(&ns->ns_owner_node, &owner->ns_owner_root, ns_cmp_owner);
} else {
/* Only the initial user namespace doesn't have an owner. */
VFS_WARN_ON_ONCE(ns != to_ns_common(&init_user_ns));
}
}
VFS_WARN_ON_ONCE(node);
}
void __ns_tree_remove(struct ns_common *ns, struct ns_tree_root *ns_tree)
{
const struct proc_ns_operations *ops = ns->ops;
struct user_namespace *user_ns;
VFS_WARN_ON_ONCE(ns_tree_node_empty(&ns->ns_tree_node));
VFS_WARN_ON_ONCE(list_empty(&ns->ns_tree_node.ns_list_entry));
write_seqlock(&ns_tree_lock);
/* Remove from per-type tree and list */
ns_tree_node_del(&ns->ns_tree_node, ns_tree);
/* Remove from unified tree and list */
ns_tree_node_del(&ns->ns_unified_node, &ns_unified_root);
/* Remove from owner's tree if applicable */
if (ops) {
user_ns = ops->owner(ns);
if (user_ns) {
struct ns_common *owner = &user_ns->ns;
ns_tree_node_del(&ns->ns_owner_node, &owner->ns_owner_root);
}
}
write_sequnlock(&ns_tree_lock);
}
EXPORT_SYMBOL_GPL(__ns_tree_remove);
static int ns_find(const void *key, const struct rb_node *node)
{
const u64 ns_id = *(u64 *)key;
const struct ns_common *ns = node_to_ns(node);
if (ns_id < ns->ns_id)
return -1;
if (ns_id > ns->ns_id)
return 1;
return 0;
}
static int ns_find_unified(const void *key, const struct rb_node *node)
{
const u64 ns_id = *(u64 *)key;
const struct ns_common *ns = node_to_ns_unified(node);
if (ns_id < ns->ns_id)
return -1;
if (ns_id > ns->ns_id)
return 1;
return 0;
}
static struct ns_tree_root *ns_tree_from_type(int ns_type)
{
switch (ns_type) {
case CLONE_NEWCGROUP:
return &cgroup_ns_tree;
case CLONE_NEWIPC:
return &ipc_ns_tree;
case CLONE_NEWNS:
return &mnt_ns_tree;
case CLONE_NEWNET:
return &net_ns_tree;
case CLONE_NEWPID:
return &pid_ns_tree;
case CLONE_NEWUSER:
return &user_ns_tree;
case CLONE_NEWUTS:
return &uts_ns_tree;
case CLONE_NEWTIME:
return &time_ns_tree;
}
return NULL;
}
static struct ns_common *__ns_unified_tree_lookup_rcu(u64 ns_id)
{
struct rb_node *node;
unsigned int seq;
do {
seq = read_seqbegin(&ns_tree_lock);
node = rb_find_rcu(&ns_id, &ns_unified_root.ns_rb, ns_find_unified);
if (node)
break;
} while (read_seqretry(&ns_tree_lock, seq));
return node_to_ns_unified(node);
}
static struct ns_common *__ns_tree_lookup_rcu(u64 ns_id, int ns_type)
{
struct ns_tree_root *ns_tree;
struct rb_node *node;
unsigned int seq;
ns_tree = ns_tree_from_type(ns_type);
if (!ns_tree)
return NULL;
do {
seq = read_seqbegin(&ns_tree_lock);
node = rb_find_rcu(&ns_id, &ns_tree->ns_rb, ns_find);
if (node)
break;
} while (read_seqretry(&ns_tree_lock, seq));
return node_to_ns(node);
}
struct ns_common *ns_tree_lookup_rcu(u64 ns_id, int ns_type)
{
RCU_LOCKDEP_WARN(!rcu_read_lock_held(), "suspicious ns_tree_lookup_rcu() usage");
if (ns_type)
return __ns_tree_lookup_rcu(ns_id, ns_type);
return __ns_unified_tree_lookup_rcu(ns_id);
}
/**
* __ns_tree_adjoined_rcu - find the next/previous namespace in the same
* tree
* @ns: namespace to start from
* @ns_tree: namespace tree to search in
* @previous: if true find the previous namespace, otherwise the next
*
* Find the next or previous namespace in the same tree as @ns. If
* there is no next/previous namespace, -ENOENT is returned.
*/
struct ns_common *__ns_tree_adjoined_rcu(struct ns_common *ns,
struct ns_tree_root *ns_tree, bool previous)
{
struct list_head *list;
RCU_LOCKDEP_WARN(!rcu_read_lock_held(), "suspicious ns_tree_adjoined_rcu() usage");
if (previous)
list = rcu_dereference(list_bidir_prev_rcu(&ns->ns_tree_node.ns_list_entry));
else
list = rcu_dereference(list_next_rcu(&ns->ns_tree_node.ns_list_entry));
if (list_is_head(list, &ns_tree->ns_list_head))
return ERR_PTR(-ENOENT);
return list_entry_rcu(list, struct ns_common, ns_tree_node.ns_list_entry);
}
/**
* __ns_tree_gen_id - generate a new namespace id
* @ns: namespace to generate id for
* @id: if non-zero, this is the initial namespace and this is a fixed id
*
* Generates a new namespace id and assigns it to the namespace. All
* namespaces types share the same id space and thus can be compared
* directly. IOW, when two ids of two namespace are equal, they are
* identical.
*/
u64 __ns_tree_gen_id(struct ns_common *ns, u64 id)
{
static atomic64_t namespace_cookie = ATOMIC64_INIT(NS_LAST_INIT_ID + 1);
if (id)
ns->ns_id = id;
else
ns->ns_id = atomic64_inc_return(&namespace_cookie);
return ns->ns_id;
}
struct klistns {
u64 __user *uns_ids;
u32 nr_ns_ids;
u64 last_ns_id;
u64 user_ns_id;
u32 ns_type;
struct user_namespace *user_ns;
bool userns_capable;
struct ns_common *first_ns;
};
static void __free_klistns_free(const struct klistns *kls)
{
if (kls->user_ns_id != LISTNS_CURRENT_USER)
put_user_ns(kls->user_ns);
if (kls->first_ns && kls->first_ns->ops)
kls->first_ns->ops->put(kls->first_ns);
}
#define NS_ALL (PID_NS | USER_NS | MNT_NS | UTS_NS | IPC_NS | NET_NS | CGROUP_NS | TIME_NS)
static int copy_ns_id_req(const struct ns_id_req __user *req,
struct ns_id_req *kreq)
{
int ret;
size_t usize;
BUILD_BUG_ON(sizeof(struct ns_id_req) != NS_ID_REQ_SIZE_VER0);
ret = get_user(usize, &req->size);
if (ret)
return -EFAULT;
if (unlikely(usize > PAGE_SIZE))
return -E2BIG;
if (unlikely(usize < NS_ID_REQ_SIZE_VER0))
return -EINVAL;
memset(kreq, 0, sizeof(*kreq));
ret = copy_struct_from_user(kreq, sizeof(*kreq), req, usize);
if (ret)
return ret;
if (kreq->spare != 0)
return -EINVAL;
if (kreq->ns_type & ~NS_ALL)
return -EOPNOTSUPP;
return 0;
}
static inline int prepare_klistns(struct klistns *kls, struct ns_id_req *kreq,
u64 __user *ns_ids, size_t nr_ns_ids)
{
kls->last_ns_id = kreq->ns_id;
kls->user_ns_id = kreq->user_ns_id;
kls->nr_ns_ids = nr_ns_ids;
kls->ns_type = kreq->ns_type;
kls->uns_ids = ns_ids;
return 0;
}
/*
* Lookup a namespace owned by owner with id >= ns_id.
* Returns the namespace with the smallest id that is >= ns_id.
*/
static struct ns_common *lookup_ns_owner_at(u64 ns_id, struct ns_common *owner)
{
struct ns_common *ret = NULL;
struct rb_node *node;
VFS_WARN_ON_ONCE(owner->ns_type != CLONE_NEWUSER);
guard(ns_tree_locked_reader)();
node = owner->ns_owner_root.ns_rb.rb_node;
while (node) {
struct ns_common *ns;
ns = node_to_ns_owner(node);
if (ns_id <= ns->ns_id) {
ret = ns;
if (ns_id == ns->ns_id)
break;
node = node->rb_left;
} else {
node = node->rb_right;
}
}
if (ret)
ret = ns_get_unless_inactive(ret);
return ret;
}
static struct ns_common *lookup_ns_id(u64 mnt_ns_id, int ns_type)
{
struct ns_common *ns;
guard(rcu)();
ns = ns_tree_lookup_rcu(mnt_ns_id, ns_type);
if (!ns)
return NULL;
if (!ns_get_unless_inactive(ns))
return NULL;
return ns;
}
static inline bool __must_check ns_requested(const struct klistns *kls,
const struct ns_common *ns)
{
return !kls->ns_type || (kls->ns_type & ns->ns_type);
}
static inline bool __must_check may_list_ns(const struct klistns *kls,
struct ns_common *ns)
{
if (kls->user_ns && kls->userns_capable)
return true;
if (is_current_namespace(ns))
return true;
return may_see_all_namespaces();
}
static inline void ns_put(struct ns_common *ns)
{
if (ns && ns->ops)
ns->ops->put(ns);
}
DEFINE_FREE(ns_put, struct ns_common *, if (!IS_ERR_OR_NULL(_T)) ns_put(_T))
static inline struct ns_common *__must_check legitimize_ns(const struct klistns *kls,
struct ns_common *candidate)
{
if (!ns_requested(kls, candidate))
return NULL;
if (!may_list_ns(kls, candidate))
return NULL;
return ns_get_unless_inactive(candidate);
}
static ssize_t do_listns_userns(struct klistns *kls)
{
u64 __user *ns_ids = kls->uns_ids;
size_t nr_ns_ids = kls->nr_ns_ids;
struct ns_common *ns = NULL, *first_ns = NULL, *prev = NULL;
const struct list_head *head;
ssize_t ret;
VFS_WARN_ON_ONCE(!kls->user_ns_id);
if (kls->user_ns_id == LISTNS_CURRENT_USER)
ns = to_ns_common(current_user_ns());
else if (kls->user_ns_id)
ns = lookup_ns_id(kls->user_ns_id, CLONE_NEWUSER);
if (!ns)
return -EINVAL;
kls->user_ns = to_user_ns(ns);
/*
* Use the rbtree to find the first namespace we care about and
* then use it's list entry to iterate from there.
*/
if (kls->last_ns_id) {
kls->first_ns = lookup_ns_owner_at(kls->last_ns_id + 1, ns);
if (!kls->first_ns)
return -ENOENT;
first_ns = kls->first_ns;
}
ret = 0;
head = &to_ns_common(kls->user_ns)->ns_owner_root.ns_list_head;
kls->userns_capable = may_see_all_namespaces();
rcu_read_lock();
if (!first_ns)
first_ns = list_entry_rcu(head->next, typeof(*first_ns), ns_owner_node.ns_list_entry);
ns = first_ns;
list_for_each_entry_from_rcu(ns, head, ns_owner_node.ns_list_entry) {
struct ns_common *valid;
if (!nr_ns_ids)
break;
valid = legitimize_ns(kls, ns);
if (!valid)
continue;
rcu_read_unlock();
ns_put(prev);
prev = valid;
if (put_user(valid->ns_id, ns_ids + ret)) {
ns_put(prev);
return -EFAULT;
}
nr_ns_ids--;
ret++;
rcu_read_lock();
}
rcu_read_unlock();
ns_put(prev);
return ret;
}
/*
* Lookup a namespace with id >= ns_id in either the unified tree or a type-specific tree.
* Returns the namespace with the smallest id that is >= ns_id.
*/
static struct ns_common *lookup_ns_id_at(u64 ns_id, int ns_type)
{
struct ns_common *ret = NULL;
struct ns_tree_root *ns_tree = NULL;
struct rb_node *node;
if (ns_type) {
ns_tree = ns_tree_from_type(ns_type);
if (!ns_tree)
return NULL;
}
guard(ns_tree_locked_reader)();
if (ns_tree)
node = ns_tree->ns_rb.rb_node;
else
node = ns_unified_root.ns_rb.rb_node;
while (node) {
struct ns_common *ns;
if (ns_type)
ns = node_to_ns(node);
else
ns = node_to_ns_unified(node);
if (ns_id <= ns->ns_id) {
if (ns_type)
ret = node_to_ns(node);
else
ret = node_to_ns_unified(node);
if (ns_id == ns->ns_id)
break;
node = node->rb_left;
} else {
node = node->rb_right;
}
}
if (ret)
ret = ns_get_unless_inactive(ret);
return ret;
}
static inline struct ns_common *first_ns_common(const struct list_head *head,
struct ns_tree_root *ns_tree)
{
if (ns_tree)
return list_entry_rcu(head->next, struct ns_common, ns_tree_node.ns_list_entry);
return list_entry_rcu(head->next, struct ns_common, ns_unified_node.ns_list_entry);
}
static inline struct ns_common *next_ns_common(struct ns_common *ns,
struct ns_tree_root *ns_tree)
{
if (ns_tree)
return list_entry_rcu(ns->ns_tree_node.ns_list_entry.next, struct ns_common, ns_tree_node.ns_list_entry);
return list_entry_rcu(ns->ns_unified_node.ns_list_entry.next, struct ns_common, ns_unified_node.ns_list_entry);
}
static inline bool ns_common_is_head(struct ns_common *ns,
const struct list_head *head,
struct ns_tree_root *ns_tree)
{
if (ns_tree)
return &ns->ns_tree_node.ns_list_entry == head;
return &ns->ns_unified_node.ns_list_entry == head;
}
static ssize_t do_listns(struct klistns *kls)
{
u64 __user *ns_ids = kls->uns_ids;
size_t nr_ns_ids = kls->nr_ns_ids;
struct ns_common *ns, *first_ns = NULL, *prev = NULL;
struct ns_tree_root *ns_tree = NULL;
const struct list_head *head;
u32 ns_type;
ssize_t ret;
if (hweight32(kls->ns_type) == 1)
ns_type = kls->ns_type;
else
ns_type = 0;
if (ns_type) {
ns_tree = ns_tree_from_type(ns_type);
if (!ns_tree)
return -EINVAL;
}
if (kls->last_ns_id) {
kls->first_ns = lookup_ns_id_at(kls->last_ns_id + 1, ns_type);
if (!kls->first_ns)
return -ENOENT;
first_ns = kls->first_ns;
}
ret = 0;
if (ns_tree)
head = &ns_tree->ns_list_head;
else
head = &ns_unified_root.ns_list_head;
rcu_read_lock();
if (!first_ns)
first_ns = first_ns_common(head, ns_tree);
for (ns = first_ns; !ns_common_is_head(ns, head, ns_tree) && nr_ns_ids;
ns = next_ns_common(ns, ns_tree)) {
struct ns_common *valid;
valid = legitimize_ns(kls, ns);
if (!valid)
continue;
rcu_read_unlock();
ns_put(prev);
prev = valid;
if (put_user(valid->ns_id, ns_ids + ret)) {
ns_put(prev);
return -EFAULT;
}
nr_ns_ids--;
ret++;
rcu_read_lock();
}
rcu_read_unlock();
ns_put(prev);
return ret;
}
SYSCALL_DEFINE4(listns, const struct ns_id_req __user *, req,
u64 __user *, ns_ids, size_t, nr_ns_ids, unsigned int, flags)
{
struct klistns klns __free(klistns_free) = {};
const size_t maxcount = 1000000;
struct ns_id_req kreq;
ssize_t ret;
if (flags)
return -EINVAL;
if (unlikely(nr_ns_ids > maxcount))
return -EOVERFLOW;
if (!access_ok(ns_ids, nr_ns_ids * sizeof(*ns_ids)))
return -EFAULT;
ret = copy_ns_id_req(req, &kreq);
if (ret)
return ret;
ret = prepare_klistns(&klns, &kreq, ns_ids, nr_ns_ids);
if (ret)
return ret;
if (kreq.user_ns_id)
return do_listns_userns(&klns);
return do_listns(&klns);
}