3 * Copyright (C) 2004-2005, 2008, 2013 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
12 #include <linux/module.h>
13 #include <linux/init.h>
14 #include <linux/sched.h>
15 #include <linux/slab.h>
16 #include <linux/security.h>
17 #include <linux/seq_file.h>
18 #include <linux/err.h>
19 #include <keys/keyring-type.h>
20 #include <keys/user-type.h>
21 #include <linux/assoc_array_priv.h>
22 #include <linux/uaccess.h>
26 * When plumbing the depths of the key tree, this sets a hard limit
27 * set on how deep we're willing to go.
29 #define KEYRING_SEARCH_MAX_DEPTH 6
32 * We keep all named keyrings in a hash to speed looking them up.
34 #define KEYRING_NAME_HASH_SIZE (1 << 5)
37 * We mark pointers we pass to the associative array with bit 1 set if
38 * they're keyrings and clear otherwise.
40 #define KEYRING_PTR_SUBTYPE 0x2UL
42 static inline bool keyring_ptr_is_keyring(const struct assoc_array_ptr
*x
)
44 return (unsigned long)x
& KEYRING_PTR_SUBTYPE
;
46 static inline struct key
*keyring_ptr_to_key(const struct assoc_array_ptr
*x
)
48 void *object
= assoc_array_ptr_to_leaf(x
);
49 return (struct key
*)((unsigned long)object
& ~KEYRING_PTR_SUBTYPE
);
51 static inline void *keyring_key_to_ptr(struct key
*key
)
53 if (key
->type
== &key_type_keyring
)
54 return (void *)((unsigned long)key
| KEYRING_PTR_SUBTYPE
);
58 static struct list_head keyring_name_hash
[KEYRING_NAME_HASH_SIZE
];
59 static DEFINE_RWLOCK(keyring_name_lock
);
61 static inline unsigned keyring_hash(const char *desc
)
66 bucket
+= (unsigned char)*desc
;
68 return bucket
& (KEYRING_NAME_HASH_SIZE
- 1);
72 * The keyring key type definition. Keyrings are simply keys of this type and
73 * can be treated as ordinary keys in addition to having their own special
76 static int keyring_instantiate(struct key
*keyring
,
77 struct key_preparsed_payload
*prep
);
78 static void keyring_revoke(struct key
*keyring
);
79 static void keyring_destroy(struct key
*keyring
);
80 static void keyring_describe(const struct key
*keyring
, struct seq_file
*m
);
81 static long keyring_read(const struct key
*keyring
,
82 char __user
*buffer
, size_t buflen
);
84 struct key_type key_type_keyring
= {
87 .instantiate
= keyring_instantiate
,
89 .revoke
= keyring_revoke
,
90 .destroy
= keyring_destroy
,
91 .describe
= keyring_describe
,
94 EXPORT_SYMBOL(key_type_keyring
);
97 * Semaphore to serialise link/link calls to prevent two link calls in parallel
98 * introducing a cycle.
100 static DECLARE_RWSEM(keyring_serialise_link_sem
);
103 * Publish the name of a keyring so that it can be found by name (if it has
106 static void keyring_publish_name(struct key
*keyring
)
110 if (keyring
->description
) {
111 bucket
= keyring_hash(keyring
->description
);
113 write_lock(&keyring_name_lock
);
115 if (!keyring_name_hash
[bucket
].next
)
116 INIT_LIST_HEAD(&keyring_name_hash
[bucket
]);
118 list_add_tail(&keyring
->type_data
.link
,
119 &keyring_name_hash
[bucket
]);
121 write_unlock(&keyring_name_lock
);
126 * Initialise a keyring.
128 * Returns 0 on success, -EINVAL if given any data.
130 static int keyring_instantiate(struct key
*keyring
,
131 struct key_preparsed_payload
*prep
)
136 if (prep
->datalen
== 0) {
137 assoc_array_init(&keyring
->keys
);
138 /* make the keyring available by name if it has one */
139 keyring_publish_name(keyring
);
147 * Multiply 64-bits by 32-bits to 96-bits and fold back to 64-bit. Ideally we'd
148 * fold the carry back too, but that requires inline asm.
150 static u64
mult_64x32_and_fold(u64 x
, u32 y
)
152 u64 hi
= (u64
)(u32
)(x
>> 32) * y
;
153 u64 lo
= (u64
)(u32
)(x
) * y
;
154 return lo
+ ((u64
)(u32
)hi
<< 32) + (u32
)(hi
>> 32);
158 * Hash a key type and description.
160 static unsigned long hash_key_type_and_desc(const struct keyring_index_key
*index_key
)
162 const unsigned level_shift
= ASSOC_ARRAY_LEVEL_STEP
;
163 const unsigned long level_mask
= ASSOC_ARRAY_LEVEL_STEP_MASK
;
164 const char *description
= index_key
->description
;
165 unsigned long hash
, type
;
168 int n
, desc_len
= index_key
->desc_len
;
170 type
= (unsigned long)index_key
->type
;
172 acc
= mult_64x32_and_fold(type
, desc_len
+ 13);
173 acc
= mult_64x32_and_fold(acc
, 9207);
181 memcpy(&piece
, description
, n
);
184 acc
= mult_64x32_and_fold(acc
, piece
);
185 acc
= mult_64x32_and_fold(acc
, 9207);
188 /* Fold the hash down to 32 bits if need be. */
190 if (ASSOC_ARRAY_KEY_CHUNK_SIZE
== 32)
193 /* Squidge all the keyrings into a separate part of the tree to
194 * ordinary keys by making sure the lowest level segment in the hash is
195 * zero for keyrings and non-zero otherwise.
197 if (index_key
->type
!= &key_type_keyring
&& (hash
& level_mask
) == 0)
198 return hash
| (hash
>> (ASSOC_ARRAY_KEY_CHUNK_SIZE
- level_shift
)) | 1;
199 if (index_key
->type
== &key_type_keyring
&& (hash
& level_mask
) != 0)
200 return (hash
+ (hash
<< level_shift
)) & ~level_mask
;
205 * Build the next index key chunk.
207 * On 32-bit systems the index key is laid out as:
210 * hash desclen typeptr desc[]
215 * hash desclen typeptr desc[]
217 * We return it one word-sized chunk at a time.
219 static unsigned long keyring_get_key_chunk(const void *data
, int level
)
221 const struct keyring_index_key
*index_key
= data
;
222 unsigned long chunk
= 0;
224 int desc_len
= index_key
->desc_len
, n
= sizeof(chunk
);
226 level
/= ASSOC_ARRAY_KEY_CHUNK_SIZE
;
229 return hash_key_type_and_desc(index_key
);
231 return ((unsigned long)index_key
->type
<< 8) | desc_len
;
234 return (u8
)((unsigned long)index_key
->type
>>
235 (ASSOC_ARRAY_KEY_CHUNK_SIZE
- 8));
239 offset
+= sizeof(chunk
) - 1;
240 offset
+= (level
- 3) * sizeof(chunk
);
241 if (offset
>= desc_len
)
249 chunk
|= ((u8
*)index_key
->description
)[--offset
];
250 } while (--desc_len
> 0);
254 chunk
|= (u8
)((unsigned long)index_key
->type
>>
255 (ASSOC_ARRAY_KEY_CHUNK_SIZE
- 8));
261 static unsigned long keyring_get_object_key_chunk(const void *object
, int level
)
263 const struct key
*key
= keyring_ptr_to_key(object
);
264 return keyring_get_key_chunk(&key
->index_key
, level
);
267 static bool keyring_compare_object(const void *object
, const void *data
)
269 const struct keyring_index_key
*index_key
= data
;
270 const struct key
*key
= keyring_ptr_to_key(object
);
272 return key
->index_key
.type
== index_key
->type
&&
273 key
->index_key
.desc_len
== index_key
->desc_len
&&
274 memcmp(key
->index_key
.description
, index_key
->description
,
275 index_key
->desc_len
) == 0;
279 * Compare the index keys of a pair of objects and determine the bit position
280 * at which they differ - if they differ.
282 static int keyring_diff_objects(const void *_a
, const void *_b
)
284 const struct key
*key_a
= keyring_ptr_to_key(_a
);
285 const struct key
*key_b
= keyring_ptr_to_key(_b
);
286 const struct keyring_index_key
*a
= &key_a
->index_key
;
287 const struct keyring_index_key
*b
= &key_b
->index_key
;
288 unsigned long seg_a
, seg_b
;
292 seg_a
= hash_key_type_and_desc(a
);
293 seg_b
= hash_key_type_and_desc(b
);
294 if ((seg_a
^ seg_b
) != 0)
297 /* The number of bits contributed by the hash is controlled by a
298 * constant in the assoc_array headers. Everything else thereafter we
299 * can deal with as being machine word-size dependent.
301 level
+= ASSOC_ARRAY_KEY_CHUNK_SIZE
/ 8;
304 if ((seg_a
^ seg_b
) != 0)
307 /* The next bit may not work on big endian */
309 seg_a
= (unsigned long)a
->type
;
310 seg_b
= (unsigned long)b
->type
;
311 if ((seg_a
^ seg_b
) != 0)
314 level
+= sizeof(unsigned long);
315 if (a
->desc_len
== 0)
319 if (((unsigned long)a
->description
| (unsigned long)b
->description
) &
320 (sizeof(unsigned long) - 1)) {
322 seg_a
= *(unsigned long *)(a
->description
+ i
);
323 seg_b
= *(unsigned long *)(b
->description
+ i
);
324 if ((seg_a
^ seg_b
) != 0)
326 i
+= sizeof(unsigned long);
327 } while (i
< (a
->desc_len
& (sizeof(unsigned long) - 1)));
330 for (; i
< a
->desc_len
; i
++) {
331 seg_a
= *(unsigned char *)(a
->description
+ i
);
332 seg_b
= *(unsigned char *)(b
->description
+ i
);
333 if ((seg_a
^ seg_b
) != 0)
343 i
= level
* 8 + __ffs(seg_a
^ seg_b
);
348 * Free an object after stripping the keyring flag off of the pointer.
350 static void keyring_free_object(void *object
)
352 key_put(keyring_ptr_to_key(object
));
356 * Operations for keyring management by the index-tree routines.
358 static const struct assoc_array_ops keyring_assoc_array_ops
= {
359 .get_key_chunk
= keyring_get_key_chunk
,
360 .get_object_key_chunk
= keyring_get_object_key_chunk
,
361 .compare_object
= keyring_compare_object
,
362 .diff_objects
= keyring_diff_objects
,
363 .free_object
= keyring_free_object
,
367 * Clean up a keyring when it is destroyed. Unpublish its name if it had one
368 * and dispose of its data.
370 * The garbage collector detects the final key_put(), removes the keyring from
371 * the serial number tree and then does RCU synchronisation before coming here,
372 * so we shouldn't need to worry about code poking around here with the RCU
373 * readlock held by this time.
375 static void keyring_destroy(struct key
*keyring
)
377 if (keyring
->description
) {
378 write_lock(&keyring_name_lock
);
380 if (keyring
->type_data
.link
.next
!= NULL
&&
381 !list_empty(&keyring
->type_data
.link
))
382 list_del(&keyring
->type_data
.link
);
384 write_unlock(&keyring_name_lock
);
387 assoc_array_destroy(&keyring
->keys
, &keyring_assoc_array_ops
);
391 * Describe a keyring for /proc.
393 static void keyring_describe(const struct key
*keyring
, struct seq_file
*m
)
395 if (keyring
->description
)
396 seq_puts(m
, keyring
->description
);
398 seq_puts(m
, "[anon]");
400 if (key_is_instantiated(keyring
)) {
401 if (keyring
->keys
.nr_leaves_on_tree
!= 0)
402 seq_printf(m
, ": %lu", keyring
->keys
.nr_leaves_on_tree
);
404 seq_puts(m
, ": empty");
408 struct keyring_read_iterator_context
{
411 key_serial_t __user
*buffer
;
414 static int keyring_read_iterator(const void *object
, void *data
)
416 struct keyring_read_iterator_context
*ctx
= data
;
417 const struct key
*key
= keyring_ptr_to_key(object
);
420 kenter("{%s,%d},,{%zu/%zu}",
421 key
->type
->name
, key
->serial
, ctx
->count
, ctx
->qty
);
423 if (ctx
->count
>= ctx
->qty
)
426 ret
= put_user(key
->serial
, ctx
->buffer
);
430 ctx
->count
+= sizeof(key
->serial
);
435 * Read a list of key IDs from the keyring's contents in binary form
437 * The keyring's semaphore is read-locked by the caller. This prevents someone
438 * from modifying it under us - which could cause us to read key IDs multiple
441 static long keyring_read(const struct key
*keyring
,
442 char __user
*buffer
, size_t buflen
)
444 struct keyring_read_iterator_context ctx
;
445 unsigned long nr_keys
;
448 kenter("{%d},,%zu", key_serial(keyring
), buflen
);
450 if (buflen
& (sizeof(key_serial_t
) - 1))
453 nr_keys
= keyring
->keys
.nr_leaves_on_tree
;
457 /* Calculate how much data we could return */
458 ctx
.qty
= nr_keys
* sizeof(key_serial_t
);
460 if (!buffer
|| !buflen
)
463 if (buflen
> ctx
.qty
)
466 /* Copy the IDs of the subscribed keys into the buffer */
467 ctx
.buffer
= (key_serial_t __user
*)buffer
;
469 ret
= assoc_array_iterate(&keyring
->keys
, keyring_read_iterator
, &ctx
);
471 kleave(" = %d [iterate]", ret
);
475 kleave(" = %zu [ok]", ctx
.count
);
480 * Allocate a keyring and link into the destination keyring.
482 struct key
*keyring_alloc(const char *description
, kuid_t uid
, kgid_t gid
,
483 const struct cred
*cred
, key_perm_t perm
,
484 unsigned long flags
, struct key
*dest
)
489 keyring
= key_alloc(&key_type_keyring
, description
,
490 uid
, gid
, cred
, perm
, flags
);
491 if (!IS_ERR(keyring
)) {
492 ret
= key_instantiate_and_link(keyring
, NULL
, 0, dest
, NULL
);
495 keyring
= ERR_PTR(ret
);
501 EXPORT_SYMBOL(keyring_alloc
);
504 * Iteration function to consider each key found.
506 static int keyring_search_iterator(const void *object
, void *iterator_data
)
508 struct keyring_search_context
*ctx
= iterator_data
;
509 const struct key
*key
= keyring_ptr_to_key(object
);
510 unsigned long kflags
= key
->flags
;
512 kenter("{%d}", key
->serial
);
514 /* ignore keys not of this type */
515 if (key
->type
!= ctx
->index_key
.type
) {
516 kleave(" = 0 [!type]");
520 /* skip invalidated, revoked and expired keys */
521 if (ctx
->flags
& KEYRING_SEARCH_DO_STATE_CHECK
) {
522 if (kflags
& ((1 << KEY_FLAG_INVALIDATED
) |
523 (1 << KEY_FLAG_REVOKED
))) {
524 ctx
->result
= ERR_PTR(-EKEYREVOKED
);
525 kleave(" = %d [invrev]", ctx
->skipped_ret
);
529 if (key
->expiry
&& ctx
->now
.tv_sec
>= key
->expiry
) {
530 ctx
->result
= ERR_PTR(-EKEYEXPIRED
);
531 kleave(" = %d [expire]", ctx
->skipped_ret
);
536 /* keys that don't match */
537 if (!ctx
->match(key
, ctx
->match_data
)) {
538 kleave(" = 0 [!match]");
542 /* key must have search permissions */
543 if (!(ctx
->flags
& KEYRING_SEARCH_NO_CHECK_PERM
) &&
544 key_task_permission(make_key_ref(key
, ctx
->possessed
),
545 ctx
->cred
, KEY_SEARCH
) < 0) {
546 ctx
->result
= ERR_PTR(-EACCES
);
547 kleave(" = %d [!perm]", ctx
->skipped_ret
);
551 if (ctx
->flags
& KEYRING_SEARCH_DO_STATE_CHECK
) {
552 /* we set a different error code if we pass a negative key */
553 if (kflags
& (1 << KEY_FLAG_NEGATIVE
)) {
554 ctx
->result
= ERR_PTR(key
->type_data
.reject_error
);
555 kleave(" = %d [neg]", ctx
->skipped_ret
);
561 ctx
->result
= make_key_ref(key
, ctx
->possessed
);
562 kleave(" = 1 [found]");
566 return ctx
->skipped_ret
;
570 * Search inside a keyring for a key. We can search by walking to it
571 * directly based on its index-key or we can iterate over the entire
572 * tree looking for it, based on the match function.
574 static int search_keyring(struct key
*keyring
, struct keyring_search_context
*ctx
)
576 if ((ctx
->flags
& KEYRING_SEARCH_LOOKUP_TYPE
) ==
577 KEYRING_SEARCH_LOOKUP_DIRECT
) {
580 object
= assoc_array_find(&keyring
->keys
,
581 &keyring_assoc_array_ops
,
583 return object
? ctx
->iterator(object
, ctx
) : 0;
585 return assoc_array_iterate(&keyring
->keys
, ctx
->iterator
, ctx
);
589 * Search a tree of keyrings that point to other keyrings up to the maximum
592 static bool search_nested_keyrings(struct key
*keyring
,
593 struct keyring_search_context
*ctx
)
597 struct assoc_array_node
*node
;
599 } stack
[KEYRING_SEARCH_MAX_DEPTH
];
601 struct assoc_array_shortcut
*shortcut
;
602 struct assoc_array_node
*node
;
603 struct assoc_array_ptr
*ptr
;
607 kenter("{%d},{%s,%s}",
609 ctx
->index_key
.type
->name
,
610 ctx
->index_key
.description
);
612 if (ctx
->index_key
.description
)
613 ctx
->index_key
.desc_len
= strlen(ctx
->index_key
.description
);
615 /* Check to see if this top-level keyring is what we are looking for
616 * and whether it is valid or not.
618 if (ctx
->flags
& KEYRING_SEARCH_LOOKUP_ITERATE
||
619 keyring_compare_object(keyring
, &ctx
->index_key
)) {
620 ctx
->skipped_ret
= 2;
621 ctx
->flags
|= KEYRING_SEARCH_DO_STATE_CHECK
;
622 switch (ctx
->iterator(keyring_key_to_ptr(keyring
), ctx
)) {
632 ctx
->skipped_ret
= 0;
633 if (ctx
->flags
& KEYRING_SEARCH_NO_STATE_CHECK
)
634 ctx
->flags
&= ~KEYRING_SEARCH_DO_STATE_CHECK
;
636 /* Start processing a new keyring */
638 kdebug("descend to %d", keyring
->serial
);
639 if (keyring
->flags
& ((1 << KEY_FLAG_INVALIDATED
) |
640 (1 << KEY_FLAG_REVOKED
)))
641 goto not_this_keyring
;
643 /* Search through the keys in this keyring before its searching its
646 if (search_keyring(keyring
, ctx
))
649 /* Then manually iterate through the keyrings nested in this one.
651 * Start from the root node of the index tree. Because of the way the
652 * hash function has been set up, keyrings cluster on the leftmost
653 * branch of the root node (root slot 0) or in the root node itself.
654 * Non-keyrings avoid the leftmost branch of the root entirely (root
657 ptr
= ACCESS_ONCE(keyring
->keys
.root
);
659 goto not_this_keyring
;
661 if (assoc_array_ptr_is_shortcut(ptr
)) {
662 /* If the root is a shortcut, either the keyring only contains
663 * keyring pointers (everything clusters behind root slot 0) or
664 * doesn't contain any keyring pointers.
666 shortcut
= assoc_array_ptr_to_shortcut(ptr
);
667 smp_read_barrier_depends();
668 if ((shortcut
->index_key
[0] & ASSOC_ARRAY_FAN_MASK
) != 0)
669 goto not_this_keyring
;
671 ptr
= ACCESS_ONCE(shortcut
->next_node
);
672 node
= assoc_array_ptr_to_node(ptr
);
676 node
= assoc_array_ptr_to_node(ptr
);
677 smp_read_barrier_depends();
679 ptr
= node
->slots
[0];
680 if (!assoc_array_ptr_is_meta(ptr
))
684 /* Descend to a more distal node in this keyring's content tree and go
688 if (assoc_array_ptr_is_shortcut(ptr
)) {
689 shortcut
= assoc_array_ptr_to_shortcut(ptr
);
690 smp_read_barrier_depends();
691 ptr
= ACCESS_ONCE(shortcut
->next_node
);
692 BUG_ON(!assoc_array_ptr_is_node(ptr
));
693 node
= assoc_array_ptr_to_node(ptr
);
697 kdebug("begin_node");
698 smp_read_barrier_depends();
701 /* Go through the slots in a node */
702 for (; slot
< ASSOC_ARRAY_FAN_OUT
; slot
++) {
703 ptr
= ACCESS_ONCE(node
->slots
[slot
]);
705 if (assoc_array_ptr_is_meta(ptr
) && node
->back_pointer
)
706 goto descend_to_node
;
708 if (!keyring_ptr_is_keyring(ptr
))
711 key
= keyring_ptr_to_key(ptr
);
713 if (sp
>= KEYRING_SEARCH_MAX_DEPTH
) {
714 if (ctx
->flags
& KEYRING_SEARCH_DETECT_TOO_DEEP
) {
715 ctx
->result
= ERR_PTR(-ELOOP
);
718 goto not_this_keyring
;
721 /* Search a nested keyring */
722 if (!(ctx
->flags
& KEYRING_SEARCH_NO_CHECK_PERM
) &&
723 key_task_permission(make_key_ref(key
, ctx
->possessed
),
724 ctx
->cred
, KEY_SEARCH
) < 0)
727 /* stack the current position */
728 stack
[sp
].keyring
= keyring
;
729 stack
[sp
].node
= node
;
730 stack
[sp
].slot
= slot
;
733 /* begin again with the new keyring */
735 goto descend_to_keyring
;
738 /* We've dealt with all the slots in the current node, so now we need
739 * to ascend to the parent and continue processing there.
741 ptr
= ACCESS_ONCE(node
->back_pointer
);
742 slot
= node
->parent_slot
;
744 if (ptr
&& assoc_array_ptr_is_shortcut(ptr
)) {
745 shortcut
= assoc_array_ptr_to_shortcut(ptr
);
746 smp_read_barrier_depends();
747 ptr
= ACCESS_ONCE(shortcut
->back_pointer
);
748 slot
= shortcut
->parent_slot
;
751 goto not_this_keyring
;
752 node
= assoc_array_ptr_to_node(ptr
);
753 smp_read_barrier_depends();
756 /* If we've ascended to the root (zero backpointer), we must have just
757 * finished processing the leftmost branch rather than the root slots -
758 * so there can't be any more keyrings for us to find.
760 if (node
->back_pointer
) {
761 kdebug("ascend %d", slot
);
765 /* The keyring we're looking at was disqualified or didn't contain a
769 kdebug("not_this_keyring %d", sp
);
775 /* Resume the processing of a keyring higher up in the tree */
777 keyring
= stack
[sp
].keyring
;
778 node
= stack
[sp
].node
;
779 slot
= stack
[sp
].slot
+ 1;
780 kdebug("ascend to %d [%d]", keyring
->serial
, slot
);
783 /* We found a viable match */
785 key
= key_ref_to_ptr(ctx
->result
);
787 if (!(ctx
->flags
& KEYRING_SEARCH_NO_UPDATE_TIME
)) {
788 key
->last_used_at
= ctx
->now
.tv_sec
;
789 keyring
->last_used_at
= ctx
->now
.tv_sec
;
791 stack
[--sp
].keyring
->last_used_at
= ctx
->now
.tv_sec
;
798 * keyring_search_aux - Search a keyring tree for a key matching some criteria
799 * @keyring_ref: A pointer to the keyring with possession indicator.
800 * @ctx: The keyring search context.
802 * Search the supplied keyring tree for a key that matches the criteria given.
803 * The root keyring and any linked keyrings must grant Search permission to the
804 * caller to be searchable and keys can only be found if they too grant Search
805 * to the caller. The possession flag on the root keyring pointer controls use
806 * of the possessor bits in permissions checking of the entire tree. In
807 * addition, the LSM gets to forbid keyring searches and key matches.
809 * The search is performed as a breadth-then-depth search up to the prescribed
810 * limit (KEYRING_SEARCH_MAX_DEPTH).
812 * Keys are matched to the type provided and are then filtered by the match
813 * function, which is given the description to use in any way it sees fit. The
814 * match function may use any attributes of a key that it wishes to to
815 * determine the match. Normally the match function from the key type would be
818 * RCU can be used to prevent the keyring key lists from disappearing without
819 * the need to take lots of locks.
821 * Returns a pointer to the found key and increments the key usage count if
822 * successful; -EAGAIN if no matching keys were found, or if expired or revoked
823 * keys were found; -ENOKEY if only negative keys were found; -ENOTDIR if the
824 * specified keyring wasn't a keyring.
826 * In the case of a successful return, the possession attribute from
827 * @keyring_ref is propagated to the returned key reference.
829 key_ref_t
keyring_search_aux(key_ref_t keyring_ref
,
830 struct keyring_search_context
*ctx
)
835 ctx
->iterator
= keyring_search_iterator
;
836 ctx
->possessed
= is_key_possessed(keyring_ref
);
837 ctx
->result
= ERR_PTR(-EAGAIN
);
839 keyring
= key_ref_to_ptr(keyring_ref
);
842 if (keyring
->type
!= &key_type_keyring
)
843 return ERR_PTR(-ENOTDIR
);
845 if (!(ctx
->flags
& KEYRING_SEARCH_NO_CHECK_PERM
)) {
846 err
= key_task_permission(keyring_ref
, ctx
->cred
, KEY_SEARCH
);
852 ctx
->now
= current_kernel_time();
853 if (search_nested_keyrings(keyring
, ctx
))
854 __key_get(key_ref_to_ptr(ctx
->result
));
860 * keyring_search - Search the supplied keyring tree for a matching key
861 * @keyring: The root of the keyring tree to be searched.
862 * @type: The type of keyring we want to find.
863 * @description: The name of the keyring we want to find.
865 * As keyring_search_aux() above, but using the current task's credentials and
866 * type's default matching function and preferred search method.
868 key_ref_t
keyring_search(key_ref_t keyring
,
869 struct key_type
*type
,
870 const char *description
)
872 struct keyring_search_context ctx
= {
873 .index_key
.type
= type
,
874 .index_key
.description
= description
,
875 .cred
= current_cred(),
876 .match
= type
->match
,
877 .match_data
= description
,
878 .flags
= (type
->def_lookup_type
|
879 KEYRING_SEARCH_DO_STATE_CHECK
),
883 return ERR_PTR(-ENOKEY
);
885 return keyring_search_aux(keyring
, &ctx
);
887 EXPORT_SYMBOL(keyring_search
);
890 * Search the given keyring for a key that might be updated.
892 * The caller must guarantee that the keyring is a keyring and that the
893 * permission is granted to modify the keyring as no check is made here. The
894 * caller must also hold a lock on the keyring semaphore.
896 * Returns a pointer to the found key with usage count incremented if
897 * successful and returns NULL if not found. Revoked and invalidated keys are
900 * If successful, the possession indicator is propagated from the keyring ref
901 * to the returned key reference.
903 key_ref_t
find_key_to_update(key_ref_t keyring_ref
,
904 const struct keyring_index_key
*index_key
)
906 struct key
*keyring
, *key
;
909 keyring
= key_ref_to_ptr(keyring_ref
);
911 kenter("{%d},{%s,%s}",
912 keyring
->serial
, index_key
->type
->name
, index_key
->description
);
914 object
= assoc_array_find(&keyring
->keys
, &keyring_assoc_array_ops
,
924 key
= keyring_ptr_to_key(object
);
925 if (key
->flags
& ((1 << KEY_FLAG_INVALIDATED
) |
926 (1 << KEY_FLAG_REVOKED
))) {
927 kleave(" = NULL [x]");
931 kleave(" = {%d}", key
->serial
);
932 return make_key_ref(key
, is_key_possessed(keyring_ref
));
936 * Find a keyring with the specified name.
938 * All named keyrings in the current user namespace are searched, provided they
939 * grant Search permission directly to the caller (unless this check is
940 * skipped). Keyrings whose usage points have reached zero or who have been
941 * revoked are skipped.
943 * Returns a pointer to the keyring with the keyring's refcount having being
944 * incremented on success. -ENOKEY is returned if a key could not be found.
946 struct key
*find_keyring_by_name(const char *name
, bool skip_perm_check
)
952 return ERR_PTR(-EINVAL
);
954 bucket
= keyring_hash(name
);
956 read_lock(&keyring_name_lock
);
958 if (keyring_name_hash
[bucket
].next
) {
959 /* search this hash bucket for a keyring with a matching name
960 * that's readable and that hasn't been revoked */
961 list_for_each_entry(keyring
,
962 &keyring_name_hash
[bucket
],
965 if (!kuid_has_mapping(current_user_ns(), keyring
->user
->uid
))
968 if (test_bit(KEY_FLAG_REVOKED
, &keyring
->flags
))
971 if (strcmp(keyring
->description
, name
) != 0)
974 if (!skip_perm_check
&&
975 key_permission(make_key_ref(keyring
, 0),
979 /* we've got a match but we might end up racing with
980 * key_cleanup() if the keyring is currently 'dead'
981 * (ie. it has a zero usage count) */
982 if (!atomic_inc_not_zero(&keyring
->usage
))
984 keyring
->last_used_at
= current_kernel_time().tv_sec
;
989 keyring
= ERR_PTR(-ENOKEY
);
991 read_unlock(&keyring_name_lock
);
995 static int keyring_detect_cycle_iterator(const void *object
,
998 struct keyring_search_context
*ctx
= iterator_data
;
999 const struct key
*key
= keyring_ptr_to_key(object
);
1001 kenter("{%d}", key
->serial
);
1003 BUG_ON(key
!= ctx
->match_data
);
1004 ctx
->result
= ERR_PTR(-EDEADLK
);
1009 * See if a cycle will will be created by inserting acyclic tree B in acyclic
1010 * tree A at the topmost level (ie: as a direct child of A).
1012 * Since we are adding B to A at the top level, checking for cycles should just
1013 * be a matter of seeing if node A is somewhere in tree B.
1015 static int keyring_detect_cycle(struct key
*A
, struct key
*B
)
1017 struct keyring_search_context ctx
= {
1018 .index_key
= A
->index_key
,
1020 .iterator
= keyring_detect_cycle_iterator
,
1021 .flags
= (KEYRING_SEARCH_LOOKUP_DIRECT
|
1022 KEYRING_SEARCH_NO_STATE_CHECK
|
1023 KEYRING_SEARCH_NO_UPDATE_TIME
|
1024 KEYRING_SEARCH_NO_CHECK_PERM
|
1025 KEYRING_SEARCH_DETECT_TOO_DEEP
),
1029 search_nested_keyrings(B
, &ctx
);
1031 return PTR_ERR(ctx
.result
) == -EAGAIN
? 0 : PTR_ERR(ctx
.result
);
1035 * Preallocate memory so that a key can be linked into to a keyring.
1037 int __key_link_begin(struct key
*keyring
,
1038 const struct keyring_index_key
*index_key
,
1039 struct assoc_array_edit
**_edit
)
1040 __acquires(&keyring
->sem
)
1041 __acquires(&keyring_serialise_link_sem
)
1043 struct assoc_array_edit
*edit
;
1047 keyring
->serial
, index_key
->type
->name
, index_key
->description
);
1049 BUG_ON(index_key
->desc_len
== 0);
1051 if (keyring
->type
!= &key_type_keyring
)
1054 down_write(&keyring
->sem
);
1057 if (test_bit(KEY_FLAG_REVOKED
, &keyring
->flags
))
1060 /* serialise link/link calls to prevent parallel calls causing a cycle
1061 * when linking two keyring in opposite orders */
1062 if (index_key
->type
== &key_type_keyring
)
1063 down_write(&keyring_serialise_link_sem
);
1065 /* check that we aren't going to overrun the user's quota */
1066 ret
= key_payload_reserve(keyring
,
1067 keyring
->datalen
+ KEYQUOTA_LINK_BYTES
);
1071 /* Create an edit script that will insert/replace the key in the
1074 edit
= assoc_array_insert(&keyring
->keys
,
1075 &keyring_assoc_array_ops
,
1079 ret
= PTR_ERR(edit
);
1088 /* undo the quota changes */
1089 key_payload_reserve(keyring
,
1090 keyring
->datalen
- KEYQUOTA_LINK_BYTES
);
1092 if (index_key
->type
== &key_type_keyring
)
1093 up_write(&keyring_serialise_link_sem
);
1095 up_write(&keyring
->sem
);
1096 kleave(" = %d", ret
);
1101 * Check already instantiated keys aren't going to be a problem.
1103 * The caller must have called __key_link_begin(). Don't need to call this for
1104 * keys that were created since __key_link_begin() was called.
1106 int __key_link_check_live_key(struct key
*keyring
, struct key
*key
)
1108 if (key
->type
== &key_type_keyring
)
1109 /* check that we aren't going to create a cycle by linking one
1110 * keyring to another */
1111 return keyring_detect_cycle(keyring
, key
);
1116 * Link a key into to a keyring.
1118 * Must be called with __key_link_begin() having being called. Discards any
1119 * already extant link to matching key if there is one, so that each keyring
1120 * holds at most one link to any given key of a particular type+description
1123 void __key_link(struct key
*key
, struct assoc_array_edit
**_edit
)
1126 assoc_array_insert_set_object(*_edit
, keyring_key_to_ptr(key
));
1127 assoc_array_apply_edit(*_edit
);
1132 * Finish linking a key into to a keyring.
1134 * Must be called with __key_link_begin() having being called.
1136 void __key_link_end(struct key
*keyring
,
1137 const struct keyring_index_key
*index_key
,
1138 struct assoc_array_edit
*edit
)
1139 __releases(&keyring
->sem
)
1140 __releases(&keyring_serialise_link_sem
)
1142 BUG_ON(index_key
->type
== NULL
);
1143 kenter("%d,%s,", keyring
->serial
, index_key
->type
->name
);
1145 if (index_key
->type
== &key_type_keyring
)
1146 up_write(&keyring_serialise_link_sem
);
1149 key_payload_reserve(keyring
,
1150 keyring
->datalen
- KEYQUOTA_LINK_BYTES
);
1151 assoc_array_cancel_edit(edit
);
1153 up_write(&keyring
->sem
);
1157 * key_link - Link a key to a keyring
1158 * @keyring: The keyring to make the link in.
1159 * @key: The key to link to.
1161 * Make a link in a keyring to a key, such that the keyring holds a reference
1162 * on that key and the key can potentially be found by searching that keyring.
1164 * This function will write-lock the keyring's semaphore and will consume some
1165 * of the user's key data quota to hold the link.
1167 * Returns 0 if successful, -ENOTDIR if the keyring isn't a keyring,
1168 * -EKEYREVOKED if the keyring has been revoked, -ENFILE if the keyring is
1169 * full, -EDQUOT if there is insufficient key data quota remaining to add
1170 * another link or -ENOMEM if there's insufficient memory.
1172 * It is assumed that the caller has checked that it is permitted for a link to
1173 * be made (the keyring should have Write permission and the key Link
1176 int key_link(struct key
*keyring
, struct key
*key
)
1178 struct assoc_array_edit
*edit
;
1181 kenter("{%d,%d}", keyring
->serial
, atomic_read(&keyring
->usage
));
1186 if (test_bit(KEY_FLAG_TRUSTED_ONLY
, &keyring
->flags
) &&
1187 !test_bit(KEY_FLAG_TRUSTED
, &key
->flags
))
1190 ret
= __key_link_begin(keyring
, &key
->index_key
, &edit
);
1192 kdebug("begun {%d,%d}", keyring
->serial
, atomic_read(&keyring
->usage
));
1193 ret
= __key_link_check_live_key(keyring
, key
);
1195 __key_link(key
, &edit
);
1196 __key_link_end(keyring
, &key
->index_key
, edit
);
1199 kleave(" = %d {%d,%d}", ret
, keyring
->serial
, atomic_read(&keyring
->usage
));
1202 EXPORT_SYMBOL(key_link
);
1205 * key_unlink - Unlink the first link to a key from a keyring.
1206 * @keyring: The keyring to remove the link from.
1207 * @key: The key the link is to.
1209 * Remove a link from a keyring to a key.
1211 * This function will write-lock the keyring's semaphore.
1213 * Returns 0 if successful, -ENOTDIR if the keyring isn't a keyring, -ENOENT if
1214 * the key isn't linked to by the keyring or -ENOMEM if there's insufficient
1217 * It is assumed that the caller has checked that it is permitted for a link to
1218 * be removed (the keyring should have Write permission; no permissions are
1219 * required on the key).
1221 int key_unlink(struct key
*keyring
, struct key
*key
)
1223 struct assoc_array_edit
*edit
;
1229 if (keyring
->type
!= &key_type_keyring
)
1232 down_write(&keyring
->sem
);
1234 edit
= assoc_array_delete(&keyring
->keys
, &keyring_assoc_array_ops
,
1237 ret
= PTR_ERR(edit
);
1244 assoc_array_apply_edit(edit
);
1248 up_write(&keyring
->sem
);
1251 EXPORT_SYMBOL(key_unlink
);
1254 * keyring_clear - Clear a keyring
1255 * @keyring: The keyring to clear.
1257 * Clear the contents of the specified keyring.
1259 * Returns 0 if successful or -ENOTDIR if the keyring isn't a keyring.
1261 int keyring_clear(struct key
*keyring
)
1263 struct assoc_array_edit
*edit
;
1266 if (keyring
->type
!= &key_type_keyring
)
1269 down_write(&keyring
->sem
);
1271 edit
= assoc_array_clear(&keyring
->keys
, &keyring_assoc_array_ops
);
1273 ret
= PTR_ERR(edit
);
1276 assoc_array_apply_edit(edit
);
1277 key_payload_reserve(keyring
, 0);
1281 up_write(&keyring
->sem
);
1284 EXPORT_SYMBOL(keyring_clear
);
1287 * Dispose of the links from a revoked keyring.
1289 * This is called with the key sem write-locked.
1291 static void keyring_revoke(struct key
*keyring
)
1293 struct assoc_array_edit
*edit
;
1295 edit
= assoc_array_clear(&keyring
->keys
, &keyring_assoc_array_ops
);
1296 if (!IS_ERR(edit
)) {
1298 assoc_array_apply_edit(edit
);
1299 key_payload_reserve(keyring
, 0);
1303 static bool gc_iterator(void *object
, void *iterator_data
)
1305 struct key
*key
= keyring_ptr_to_key(object
);
1306 time_t *limit
= iterator_data
;
1308 if (key_is_dead(key
, *limit
))
1315 * Collect garbage from the contents of a keyring, replacing the old list with
1316 * a new one with the pointers all shuffled down.
1318 * Dead keys are classed as oned that are flagged as being dead or are revoked,
1319 * expired or negative keys that were revoked or expired before the specified
1322 void keyring_gc(struct key
*keyring
, time_t limit
)
1324 kenter("{%x,%s}", key_serial(keyring
), keyring
->description
);
1326 down_write(&keyring
->sem
);
1327 assoc_array_gc(&keyring
->keys
, &keyring_assoc_array_ops
,
1328 gc_iterator
, &limit
);
1329 up_write(&keyring
->sem
);