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![Paul E. McKenney](/assets/img/avatar_default.png)
Now that the associative-array library properly heads dependency chains, the various smp_read_barrier_depends() calls in security/keys/keyring.c are no longer needed. This commit therefore removes them. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: David Howells <dhowells@redhat.com> Cc: "Serge E. Hallyn" <serge@hallyn.com> Cc: <keyrings@vger.kernel.org> Cc: <linux-security-module@vger.kernel.org> Reviewed-by: James Morris <james.l.morris@oracle.com>
1586 lines
42 KiB
C
1586 lines
42 KiB
C
/* Keyring handling
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*
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* Copyright (C) 2004-2005, 2008, 2013 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/security.h>
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#include <linux/seq_file.h>
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#include <linux/err.h>
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#include <keys/keyring-type.h>
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#include <keys/user-type.h>
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#include <linux/assoc_array_priv.h>
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#include <linux/uaccess.h>
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#include "internal.h"
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/*
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* When plumbing the depths of the key tree, this sets a hard limit
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* set on how deep we're willing to go.
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*/
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#define KEYRING_SEARCH_MAX_DEPTH 6
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/*
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* We keep all named keyrings in a hash to speed looking them up.
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*/
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#define KEYRING_NAME_HASH_SIZE (1 << 5)
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/*
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* We mark pointers we pass to the associative array with bit 1 set if
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* they're keyrings and clear otherwise.
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*/
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#define KEYRING_PTR_SUBTYPE 0x2UL
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static inline bool keyring_ptr_is_keyring(const struct assoc_array_ptr *x)
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{
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return (unsigned long)x & KEYRING_PTR_SUBTYPE;
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}
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static inline struct key *keyring_ptr_to_key(const struct assoc_array_ptr *x)
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{
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void *object = assoc_array_ptr_to_leaf(x);
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return (struct key *)((unsigned long)object & ~KEYRING_PTR_SUBTYPE);
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}
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static inline void *keyring_key_to_ptr(struct key *key)
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{
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if (key->type == &key_type_keyring)
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return (void *)((unsigned long)key | KEYRING_PTR_SUBTYPE);
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return key;
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}
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static struct list_head keyring_name_hash[KEYRING_NAME_HASH_SIZE];
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static DEFINE_RWLOCK(keyring_name_lock);
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static inline unsigned keyring_hash(const char *desc)
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{
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unsigned bucket = 0;
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for (; *desc; desc++)
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bucket += (unsigned char)*desc;
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return bucket & (KEYRING_NAME_HASH_SIZE - 1);
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}
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/*
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* The keyring key type definition. Keyrings are simply keys of this type and
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* can be treated as ordinary keys in addition to having their own special
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* operations.
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*/
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static int keyring_preparse(struct key_preparsed_payload *prep);
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static void keyring_free_preparse(struct key_preparsed_payload *prep);
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static int keyring_instantiate(struct key *keyring,
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struct key_preparsed_payload *prep);
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static void keyring_revoke(struct key *keyring);
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static void keyring_destroy(struct key *keyring);
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static void keyring_describe(const struct key *keyring, struct seq_file *m);
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static long keyring_read(const struct key *keyring,
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char __user *buffer, size_t buflen);
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struct key_type key_type_keyring = {
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.name = "keyring",
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.def_datalen = 0,
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.preparse = keyring_preparse,
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.free_preparse = keyring_free_preparse,
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.instantiate = keyring_instantiate,
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.revoke = keyring_revoke,
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.destroy = keyring_destroy,
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.describe = keyring_describe,
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.read = keyring_read,
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};
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EXPORT_SYMBOL(key_type_keyring);
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/*
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* Semaphore to serialise link/link calls to prevent two link calls in parallel
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* introducing a cycle.
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*/
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static DECLARE_RWSEM(keyring_serialise_link_sem);
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/*
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* Publish the name of a keyring so that it can be found by name (if it has
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* one).
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*/
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static void keyring_publish_name(struct key *keyring)
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{
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int bucket;
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if (keyring->description) {
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bucket = keyring_hash(keyring->description);
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write_lock(&keyring_name_lock);
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if (!keyring_name_hash[bucket].next)
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INIT_LIST_HEAD(&keyring_name_hash[bucket]);
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list_add_tail(&keyring->name_link,
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&keyring_name_hash[bucket]);
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write_unlock(&keyring_name_lock);
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}
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}
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/*
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* Preparse a keyring payload
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*/
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static int keyring_preparse(struct key_preparsed_payload *prep)
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{
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return prep->datalen != 0 ? -EINVAL : 0;
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}
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/*
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* Free a preparse of a user defined key payload
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*/
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static void keyring_free_preparse(struct key_preparsed_payload *prep)
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{
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}
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/*
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* Initialise a keyring.
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*
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* Returns 0 on success, -EINVAL if given any data.
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*/
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static int keyring_instantiate(struct key *keyring,
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struct key_preparsed_payload *prep)
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{
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assoc_array_init(&keyring->keys);
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/* make the keyring available by name if it has one */
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keyring_publish_name(keyring);
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return 0;
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}
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/*
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* Multiply 64-bits by 32-bits to 96-bits and fold back to 64-bit. Ideally we'd
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* fold the carry back too, but that requires inline asm.
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*/
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static u64 mult_64x32_and_fold(u64 x, u32 y)
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{
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u64 hi = (u64)(u32)(x >> 32) * y;
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u64 lo = (u64)(u32)(x) * y;
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return lo + ((u64)(u32)hi << 32) + (u32)(hi >> 32);
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}
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/*
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* Hash a key type and description.
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*/
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static unsigned long hash_key_type_and_desc(const struct keyring_index_key *index_key)
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{
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const unsigned level_shift = ASSOC_ARRAY_LEVEL_STEP;
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const unsigned long fan_mask = ASSOC_ARRAY_FAN_MASK;
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const char *description = index_key->description;
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unsigned long hash, type;
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u32 piece;
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u64 acc;
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int n, desc_len = index_key->desc_len;
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type = (unsigned long)index_key->type;
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acc = mult_64x32_and_fold(type, desc_len + 13);
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acc = mult_64x32_and_fold(acc, 9207);
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for (;;) {
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n = desc_len;
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if (n <= 0)
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break;
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if (n > 4)
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n = 4;
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piece = 0;
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memcpy(&piece, description, n);
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description += n;
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desc_len -= n;
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acc = mult_64x32_and_fold(acc, piece);
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acc = mult_64x32_and_fold(acc, 9207);
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}
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/* Fold the hash down to 32 bits if need be. */
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hash = acc;
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if (ASSOC_ARRAY_KEY_CHUNK_SIZE == 32)
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hash ^= acc >> 32;
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/* Squidge all the keyrings into a separate part of the tree to
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* ordinary keys by making sure the lowest level segment in the hash is
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* zero for keyrings and non-zero otherwise.
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*/
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if (index_key->type != &key_type_keyring && (hash & fan_mask) == 0)
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return hash | (hash >> (ASSOC_ARRAY_KEY_CHUNK_SIZE - level_shift)) | 1;
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if (index_key->type == &key_type_keyring && (hash & fan_mask) != 0)
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return (hash + (hash << level_shift)) & ~fan_mask;
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return hash;
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}
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/*
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* Build the next index key chunk.
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*
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* On 32-bit systems the index key is laid out as:
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*
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* 0 4 5 9...
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* hash desclen typeptr desc[]
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*
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* On 64-bit systems:
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*
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* 0 8 9 17...
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* hash desclen typeptr desc[]
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*
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* We return it one word-sized chunk at a time.
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*/
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static unsigned long keyring_get_key_chunk(const void *data, int level)
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{
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const struct keyring_index_key *index_key = data;
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unsigned long chunk = 0;
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long offset = 0;
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int desc_len = index_key->desc_len, n = sizeof(chunk);
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level /= ASSOC_ARRAY_KEY_CHUNK_SIZE;
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switch (level) {
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case 0:
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return hash_key_type_and_desc(index_key);
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case 1:
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return ((unsigned long)index_key->type << 8) | desc_len;
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case 2:
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if (desc_len == 0)
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return (u8)((unsigned long)index_key->type >>
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(ASSOC_ARRAY_KEY_CHUNK_SIZE - 8));
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n--;
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offset = 1;
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default:
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offset += sizeof(chunk) - 1;
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offset += (level - 3) * sizeof(chunk);
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if (offset >= desc_len)
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return 0;
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desc_len -= offset;
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if (desc_len > n)
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desc_len = n;
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offset += desc_len;
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do {
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chunk <<= 8;
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chunk |= ((u8*)index_key->description)[--offset];
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} while (--desc_len > 0);
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if (level == 2) {
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chunk <<= 8;
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chunk |= (u8)((unsigned long)index_key->type >>
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(ASSOC_ARRAY_KEY_CHUNK_SIZE - 8));
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}
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return chunk;
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}
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}
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static unsigned long keyring_get_object_key_chunk(const void *object, int level)
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{
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const struct key *key = keyring_ptr_to_key(object);
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return keyring_get_key_chunk(&key->index_key, level);
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}
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static bool keyring_compare_object(const void *object, const void *data)
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{
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const struct keyring_index_key *index_key = data;
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const struct key *key = keyring_ptr_to_key(object);
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return key->index_key.type == index_key->type &&
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key->index_key.desc_len == index_key->desc_len &&
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memcmp(key->index_key.description, index_key->description,
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index_key->desc_len) == 0;
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}
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/*
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* Compare the index keys of a pair of objects and determine the bit position
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* at which they differ - if they differ.
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*/
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static int keyring_diff_objects(const void *object, const void *data)
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{
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const struct key *key_a = keyring_ptr_to_key(object);
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const struct keyring_index_key *a = &key_a->index_key;
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const struct keyring_index_key *b = data;
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unsigned long seg_a, seg_b;
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int level, i;
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level = 0;
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seg_a = hash_key_type_and_desc(a);
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seg_b = hash_key_type_and_desc(b);
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if ((seg_a ^ seg_b) != 0)
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goto differ;
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/* The number of bits contributed by the hash is controlled by a
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* constant in the assoc_array headers. Everything else thereafter we
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* can deal with as being machine word-size dependent.
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*/
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level += ASSOC_ARRAY_KEY_CHUNK_SIZE / 8;
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seg_a = a->desc_len;
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seg_b = b->desc_len;
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if ((seg_a ^ seg_b) != 0)
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goto differ;
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/* The next bit may not work on big endian */
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level++;
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seg_a = (unsigned long)a->type;
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seg_b = (unsigned long)b->type;
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if ((seg_a ^ seg_b) != 0)
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goto differ;
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level += sizeof(unsigned long);
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if (a->desc_len == 0)
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goto same;
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i = 0;
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if (((unsigned long)a->description | (unsigned long)b->description) &
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(sizeof(unsigned long) - 1)) {
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do {
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seg_a = *(unsigned long *)(a->description + i);
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seg_b = *(unsigned long *)(b->description + i);
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if ((seg_a ^ seg_b) != 0)
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goto differ_plus_i;
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i += sizeof(unsigned long);
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} while (i < (a->desc_len & (sizeof(unsigned long) - 1)));
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}
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for (; i < a->desc_len; i++) {
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seg_a = *(unsigned char *)(a->description + i);
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seg_b = *(unsigned char *)(b->description + i);
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if ((seg_a ^ seg_b) != 0)
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goto differ_plus_i;
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}
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same:
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return -1;
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differ_plus_i:
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level += i;
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differ:
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i = level * 8 + __ffs(seg_a ^ seg_b);
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return i;
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}
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/*
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* Free an object after stripping the keyring flag off of the pointer.
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*/
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static void keyring_free_object(void *object)
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{
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key_put(keyring_ptr_to_key(object));
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}
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/*
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* Operations for keyring management by the index-tree routines.
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*/
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static const struct assoc_array_ops keyring_assoc_array_ops = {
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.get_key_chunk = keyring_get_key_chunk,
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.get_object_key_chunk = keyring_get_object_key_chunk,
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.compare_object = keyring_compare_object,
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.diff_objects = keyring_diff_objects,
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.free_object = keyring_free_object,
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};
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/*
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* Clean up a keyring when it is destroyed. Unpublish its name if it had one
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* and dispose of its data.
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*
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* The garbage collector detects the final key_put(), removes the keyring from
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* the serial number tree and then does RCU synchronisation before coming here,
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* so we shouldn't need to worry about code poking around here with the RCU
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* readlock held by this time.
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*/
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static void keyring_destroy(struct key *keyring)
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{
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if (keyring->description) {
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write_lock(&keyring_name_lock);
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if (keyring->name_link.next != NULL &&
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!list_empty(&keyring->name_link))
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list_del(&keyring->name_link);
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write_unlock(&keyring_name_lock);
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}
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if (keyring->restrict_link) {
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struct key_restriction *keyres = keyring->restrict_link;
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key_put(keyres->key);
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kfree(keyres);
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}
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assoc_array_destroy(&keyring->keys, &keyring_assoc_array_ops);
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}
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/*
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* Describe a keyring for /proc.
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*/
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static void keyring_describe(const struct key *keyring, struct seq_file *m)
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{
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if (keyring->description)
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seq_puts(m, keyring->description);
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else
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seq_puts(m, "[anon]");
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if (key_is_positive(keyring)) {
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if (keyring->keys.nr_leaves_on_tree != 0)
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seq_printf(m, ": %lu", keyring->keys.nr_leaves_on_tree);
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else
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seq_puts(m, ": empty");
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}
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}
|
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|
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struct keyring_read_iterator_context {
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size_t buflen;
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size_t count;
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key_serial_t __user *buffer;
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};
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|
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static int keyring_read_iterator(const void *object, void *data)
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{
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struct keyring_read_iterator_context *ctx = data;
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const struct key *key = keyring_ptr_to_key(object);
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int ret;
|
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|
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kenter("{%s,%d},,{%zu/%zu}",
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key->type->name, key->serial, ctx->count, ctx->buflen);
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|
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if (ctx->count >= ctx->buflen)
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return 1;
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|
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ret = put_user(key->serial, ctx->buffer);
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if (ret < 0)
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return ret;
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ctx->buffer++;
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ctx->count += sizeof(key->serial);
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return 0;
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}
|
|
|
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/*
|
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* Read a list of key IDs from the keyring's contents in binary form
|
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*
|
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* The keyring's semaphore is read-locked by the caller. This prevents someone
|
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* from modifying it under us - which could cause us to read key IDs multiple
|
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* times.
|
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*/
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static long keyring_read(const struct key *keyring,
|
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char __user *buffer, size_t buflen)
|
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{
|
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struct keyring_read_iterator_context ctx;
|
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long ret;
|
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|
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kenter("{%d},,%zu", key_serial(keyring), buflen);
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|
|
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if (buflen & (sizeof(key_serial_t) - 1))
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return -EINVAL;
|
|
|
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/* Copy as many key IDs as fit into the buffer */
|
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if (buffer && buflen) {
|
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ctx.buffer = (key_serial_t __user *)buffer;
|
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ctx.buflen = buflen;
|
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ctx.count = 0;
|
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ret = assoc_array_iterate(&keyring->keys,
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keyring_read_iterator, &ctx);
|
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if (ret < 0) {
|
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kleave(" = %ld [iterate]", ret);
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return ret;
|
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}
|
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}
|
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|
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/* Return the size of the buffer needed */
|
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ret = keyring->keys.nr_leaves_on_tree * sizeof(key_serial_t);
|
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if (ret <= buflen)
|
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kleave("= %ld [ok]", ret);
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else
|
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kleave("= %ld [buffer too small]", ret);
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return ret;
|
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}
|
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|
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/*
|
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* Allocate a keyring and link into the destination keyring.
|
|
*/
|
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struct key *keyring_alloc(const char *description, kuid_t uid, kgid_t gid,
|
|
const struct cred *cred, key_perm_t perm,
|
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unsigned long flags,
|
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struct key_restriction *restrict_link,
|
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struct key *dest)
|
|
{
|
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struct key *keyring;
|
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int ret;
|
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|
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keyring = key_alloc(&key_type_keyring, description,
|
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uid, gid, cred, perm, flags, restrict_link);
|
|
if (!IS_ERR(keyring)) {
|
|
ret = key_instantiate_and_link(keyring, NULL, 0, dest, NULL);
|
|
if (ret < 0) {
|
|
key_put(keyring);
|
|
keyring = ERR_PTR(ret);
|
|
}
|
|
}
|
|
|
|
return keyring;
|
|
}
|
|
EXPORT_SYMBOL(keyring_alloc);
|
|
|
|
/**
|
|
* restrict_link_reject - Give -EPERM to restrict link
|
|
* @keyring: The keyring being added to.
|
|
* @type: The type of key being added.
|
|
* @payload: The payload of the key intended to be added.
|
|
* @data: Additional data for evaluating restriction.
|
|
*
|
|
* Reject the addition of any links to a keyring. It can be overridden by
|
|
* passing KEY_ALLOC_BYPASS_RESTRICTION to key_instantiate_and_link() when
|
|
* adding a key to a keyring.
|
|
*
|
|
* This is meant to be stored in a key_restriction structure which is passed
|
|
* in the restrict_link parameter to keyring_alloc().
|
|
*/
|
|
int restrict_link_reject(struct key *keyring,
|
|
const struct key_type *type,
|
|
const union key_payload *payload,
|
|
struct key *restriction_key)
|
|
{
|
|
return -EPERM;
|
|
}
|
|
|
|
/*
|
|
* By default, we keys found by getting an exact match on their descriptions.
|
|
*/
|
|
bool key_default_cmp(const struct key *key,
|
|
const struct key_match_data *match_data)
|
|
{
|
|
return strcmp(key->description, match_data->raw_data) == 0;
|
|
}
|
|
|
|
/*
|
|
* Iteration function to consider each key found.
|
|
*/
|
|
static int keyring_search_iterator(const void *object, void *iterator_data)
|
|
{
|
|
struct keyring_search_context *ctx = iterator_data;
|
|
const struct key *key = keyring_ptr_to_key(object);
|
|
unsigned long kflags = READ_ONCE(key->flags);
|
|
short state = READ_ONCE(key->state);
|
|
|
|
kenter("{%d}", key->serial);
|
|
|
|
/* ignore keys not of this type */
|
|
if (key->type != ctx->index_key.type) {
|
|
kleave(" = 0 [!type]");
|
|
return 0;
|
|
}
|
|
|
|
/* skip invalidated, revoked and expired keys */
|
|
if (ctx->flags & KEYRING_SEARCH_DO_STATE_CHECK) {
|
|
time64_t expiry = READ_ONCE(key->expiry);
|
|
|
|
if (kflags & ((1 << KEY_FLAG_INVALIDATED) |
|
|
(1 << KEY_FLAG_REVOKED))) {
|
|
ctx->result = ERR_PTR(-EKEYREVOKED);
|
|
kleave(" = %d [invrev]", ctx->skipped_ret);
|
|
goto skipped;
|
|
}
|
|
|
|
if (expiry && ctx->now >= expiry) {
|
|
if (!(ctx->flags & KEYRING_SEARCH_SKIP_EXPIRED))
|
|
ctx->result = ERR_PTR(-EKEYEXPIRED);
|
|
kleave(" = %d [expire]", ctx->skipped_ret);
|
|
goto skipped;
|
|
}
|
|
}
|
|
|
|
/* keys that don't match */
|
|
if (!ctx->match_data.cmp(key, &ctx->match_data)) {
|
|
kleave(" = 0 [!match]");
|
|
return 0;
|
|
}
|
|
|
|
/* key must have search permissions */
|
|
if (!(ctx->flags & KEYRING_SEARCH_NO_CHECK_PERM) &&
|
|
key_task_permission(make_key_ref(key, ctx->possessed),
|
|
ctx->cred, KEY_NEED_SEARCH) < 0) {
|
|
ctx->result = ERR_PTR(-EACCES);
|
|
kleave(" = %d [!perm]", ctx->skipped_ret);
|
|
goto skipped;
|
|
}
|
|
|
|
if (ctx->flags & KEYRING_SEARCH_DO_STATE_CHECK) {
|
|
/* we set a different error code if we pass a negative key */
|
|
if (state < 0) {
|
|
ctx->result = ERR_PTR(state);
|
|
kleave(" = %d [neg]", ctx->skipped_ret);
|
|
goto skipped;
|
|
}
|
|
}
|
|
|
|
/* Found */
|
|
ctx->result = make_key_ref(key, ctx->possessed);
|
|
kleave(" = 1 [found]");
|
|
return 1;
|
|
|
|
skipped:
|
|
return ctx->skipped_ret;
|
|
}
|
|
|
|
/*
|
|
* Search inside a keyring for a key. We can search by walking to it
|
|
* directly based on its index-key or we can iterate over the entire
|
|
* tree looking for it, based on the match function.
|
|
*/
|
|
static int search_keyring(struct key *keyring, struct keyring_search_context *ctx)
|
|
{
|
|
if (ctx->match_data.lookup_type == KEYRING_SEARCH_LOOKUP_DIRECT) {
|
|
const void *object;
|
|
|
|
object = assoc_array_find(&keyring->keys,
|
|
&keyring_assoc_array_ops,
|
|
&ctx->index_key);
|
|
return object ? ctx->iterator(object, ctx) : 0;
|
|
}
|
|
return assoc_array_iterate(&keyring->keys, ctx->iterator, ctx);
|
|
}
|
|
|
|
/*
|
|
* Search a tree of keyrings that point to other keyrings up to the maximum
|
|
* depth.
|
|
*/
|
|
static bool search_nested_keyrings(struct key *keyring,
|
|
struct keyring_search_context *ctx)
|
|
{
|
|
struct {
|
|
struct key *keyring;
|
|
struct assoc_array_node *node;
|
|
int slot;
|
|
} stack[KEYRING_SEARCH_MAX_DEPTH];
|
|
|
|
struct assoc_array_shortcut *shortcut;
|
|
struct assoc_array_node *node;
|
|
struct assoc_array_ptr *ptr;
|
|
struct key *key;
|
|
int sp = 0, slot;
|
|
|
|
kenter("{%d},{%s,%s}",
|
|
keyring->serial,
|
|
ctx->index_key.type->name,
|
|
ctx->index_key.description);
|
|
|
|
#define STATE_CHECKS (KEYRING_SEARCH_NO_STATE_CHECK | KEYRING_SEARCH_DO_STATE_CHECK)
|
|
BUG_ON((ctx->flags & STATE_CHECKS) == 0 ||
|
|
(ctx->flags & STATE_CHECKS) == STATE_CHECKS);
|
|
|
|
if (ctx->index_key.description)
|
|
ctx->index_key.desc_len = strlen(ctx->index_key.description);
|
|
|
|
/* Check to see if this top-level keyring is what we are looking for
|
|
* and whether it is valid or not.
|
|
*/
|
|
if (ctx->match_data.lookup_type == KEYRING_SEARCH_LOOKUP_ITERATE ||
|
|
keyring_compare_object(keyring, &ctx->index_key)) {
|
|
ctx->skipped_ret = 2;
|
|
switch (ctx->iterator(keyring_key_to_ptr(keyring), ctx)) {
|
|
case 1:
|
|
goto found;
|
|
case 2:
|
|
return false;
|
|
default:
|
|
break;
|
|
}
|
|
}
|
|
|
|
ctx->skipped_ret = 0;
|
|
|
|
/* Start processing a new keyring */
|
|
descend_to_keyring:
|
|
kdebug("descend to %d", keyring->serial);
|
|
if (keyring->flags & ((1 << KEY_FLAG_INVALIDATED) |
|
|
(1 << KEY_FLAG_REVOKED)))
|
|
goto not_this_keyring;
|
|
|
|
/* Search through the keys in this keyring before its searching its
|
|
* subtrees.
|
|
*/
|
|
if (search_keyring(keyring, ctx))
|
|
goto found;
|
|
|
|
/* Then manually iterate through the keyrings nested in this one.
|
|
*
|
|
* Start from the root node of the index tree. Because of the way the
|
|
* hash function has been set up, keyrings cluster on the leftmost
|
|
* branch of the root node (root slot 0) or in the root node itself.
|
|
* Non-keyrings avoid the leftmost branch of the root entirely (root
|
|
* slots 1-15).
|
|
*/
|
|
ptr = READ_ONCE(keyring->keys.root);
|
|
if (!ptr)
|
|
goto not_this_keyring;
|
|
|
|
if (assoc_array_ptr_is_shortcut(ptr)) {
|
|
/* If the root is a shortcut, either the keyring only contains
|
|
* keyring pointers (everything clusters behind root slot 0) or
|
|
* doesn't contain any keyring pointers.
|
|
*/
|
|
shortcut = assoc_array_ptr_to_shortcut(ptr);
|
|
if ((shortcut->index_key[0] & ASSOC_ARRAY_FAN_MASK) != 0)
|
|
goto not_this_keyring;
|
|
|
|
ptr = READ_ONCE(shortcut->next_node);
|
|
node = assoc_array_ptr_to_node(ptr);
|
|
goto begin_node;
|
|
}
|
|
|
|
node = assoc_array_ptr_to_node(ptr);
|
|
ptr = node->slots[0];
|
|
if (!assoc_array_ptr_is_meta(ptr))
|
|
goto begin_node;
|
|
|
|
descend_to_node:
|
|
/* Descend to a more distal node in this keyring's content tree and go
|
|
* through that.
|
|
*/
|
|
kdebug("descend");
|
|
if (assoc_array_ptr_is_shortcut(ptr)) {
|
|
shortcut = assoc_array_ptr_to_shortcut(ptr);
|
|
ptr = READ_ONCE(shortcut->next_node);
|
|
BUG_ON(!assoc_array_ptr_is_node(ptr));
|
|
}
|
|
node = assoc_array_ptr_to_node(ptr);
|
|
|
|
begin_node:
|
|
kdebug("begin_node");
|
|
slot = 0;
|
|
ascend_to_node:
|
|
/* Go through the slots in a node */
|
|
for (; slot < ASSOC_ARRAY_FAN_OUT; slot++) {
|
|
ptr = READ_ONCE(node->slots[slot]);
|
|
|
|
if (assoc_array_ptr_is_meta(ptr) && node->back_pointer)
|
|
goto descend_to_node;
|
|
|
|
if (!keyring_ptr_is_keyring(ptr))
|
|
continue;
|
|
|
|
key = keyring_ptr_to_key(ptr);
|
|
|
|
if (sp >= KEYRING_SEARCH_MAX_DEPTH) {
|
|
if (ctx->flags & KEYRING_SEARCH_DETECT_TOO_DEEP) {
|
|
ctx->result = ERR_PTR(-ELOOP);
|
|
return false;
|
|
}
|
|
goto not_this_keyring;
|
|
}
|
|
|
|
/* Search a nested keyring */
|
|
if (!(ctx->flags & KEYRING_SEARCH_NO_CHECK_PERM) &&
|
|
key_task_permission(make_key_ref(key, ctx->possessed),
|
|
ctx->cred, KEY_NEED_SEARCH) < 0)
|
|
continue;
|
|
|
|
/* stack the current position */
|
|
stack[sp].keyring = keyring;
|
|
stack[sp].node = node;
|
|
stack[sp].slot = slot;
|
|
sp++;
|
|
|
|
/* begin again with the new keyring */
|
|
keyring = key;
|
|
goto descend_to_keyring;
|
|
}
|
|
|
|
/* We've dealt with all the slots in the current node, so now we need
|
|
* to ascend to the parent and continue processing there.
|
|
*/
|
|
ptr = READ_ONCE(node->back_pointer);
|
|
slot = node->parent_slot;
|
|
|
|
if (ptr && assoc_array_ptr_is_shortcut(ptr)) {
|
|
shortcut = assoc_array_ptr_to_shortcut(ptr);
|
|
ptr = READ_ONCE(shortcut->back_pointer);
|
|
slot = shortcut->parent_slot;
|
|
}
|
|
if (!ptr)
|
|
goto not_this_keyring;
|
|
node = assoc_array_ptr_to_node(ptr);
|
|
slot++;
|
|
|
|
/* If we've ascended to the root (zero backpointer), we must have just
|
|
* finished processing the leftmost branch rather than the root slots -
|
|
* so there can't be any more keyrings for us to find.
|
|
*/
|
|
if (node->back_pointer) {
|
|
kdebug("ascend %d", slot);
|
|
goto ascend_to_node;
|
|
}
|
|
|
|
/* The keyring we're looking at was disqualified or didn't contain a
|
|
* matching key.
|
|
*/
|
|
not_this_keyring:
|
|
kdebug("not_this_keyring %d", sp);
|
|
if (sp <= 0) {
|
|
kleave(" = false");
|
|
return false;
|
|
}
|
|
|
|
/* Resume the processing of a keyring higher up in the tree */
|
|
sp--;
|
|
keyring = stack[sp].keyring;
|
|
node = stack[sp].node;
|
|
slot = stack[sp].slot + 1;
|
|
kdebug("ascend to %d [%d]", keyring->serial, slot);
|
|
goto ascend_to_node;
|
|
|
|
/* We found a viable match */
|
|
found:
|
|
key = key_ref_to_ptr(ctx->result);
|
|
key_check(key);
|
|
if (!(ctx->flags & KEYRING_SEARCH_NO_UPDATE_TIME)) {
|
|
key->last_used_at = ctx->now;
|
|
keyring->last_used_at = ctx->now;
|
|
while (sp > 0)
|
|
stack[--sp].keyring->last_used_at = ctx->now;
|
|
}
|
|
kleave(" = true");
|
|
return true;
|
|
}
|
|
|
|
/**
|
|
* keyring_search_aux - Search a keyring tree for a key matching some criteria
|
|
* @keyring_ref: A pointer to the keyring with possession indicator.
|
|
* @ctx: The keyring search context.
|
|
*
|
|
* Search the supplied keyring tree for a key that matches the criteria given.
|
|
* The root keyring and any linked keyrings must grant Search permission to the
|
|
* caller to be searchable and keys can only be found if they too grant Search
|
|
* to the caller. The possession flag on the root keyring pointer controls use
|
|
* of the possessor bits in permissions checking of the entire tree. In
|
|
* addition, the LSM gets to forbid keyring searches and key matches.
|
|
*
|
|
* The search is performed as a breadth-then-depth search up to the prescribed
|
|
* limit (KEYRING_SEARCH_MAX_DEPTH).
|
|
*
|
|
* Keys are matched to the type provided and are then filtered by the match
|
|
* function, which is given the description to use in any way it sees fit. The
|
|
* match function may use any attributes of a key that it wishes to to
|
|
* determine the match. Normally the match function from the key type would be
|
|
* used.
|
|
*
|
|
* RCU can be used to prevent the keyring key lists from disappearing without
|
|
* the need to take lots of locks.
|
|
*
|
|
* Returns a pointer to the found key and increments the key usage count if
|
|
* successful; -EAGAIN if no matching keys were found, or if expired or revoked
|
|
* keys were found; -ENOKEY if only negative keys were found; -ENOTDIR if the
|
|
* specified keyring wasn't a keyring.
|
|
*
|
|
* In the case of a successful return, the possession attribute from
|
|
* @keyring_ref is propagated to the returned key reference.
|
|
*/
|
|
key_ref_t keyring_search_aux(key_ref_t keyring_ref,
|
|
struct keyring_search_context *ctx)
|
|
{
|
|
struct key *keyring;
|
|
long err;
|
|
|
|
ctx->iterator = keyring_search_iterator;
|
|
ctx->possessed = is_key_possessed(keyring_ref);
|
|
ctx->result = ERR_PTR(-EAGAIN);
|
|
|
|
keyring = key_ref_to_ptr(keyring_ref);
|
|
key_check(keyring);
|
|
|
|
if (keyring->type != &key_type_keyring)
|
|
return ERR_PTR(-ENOTDIR);
|
|
|
|
if (!(ctx->flags & KEYRING_SEARCH_NO_CHECK_PERM)) {
|
|
err = key_task_permission(keyring_ref, ctx->cred, KEY_NEED_SEARCH);
|
|
if (err < 0)
|
|
return ERR_PTR(err);
|
|
}
|
|
|
|
rcu_read_lock();
|
|
ctx->now = ktime_get_real_seconds();
|
|
if (search_nested_keyrings(keyring, ctx))
|
|
__key_get(key_ref_to_ptr(ctx->result));
|
|
rcu_read_unlock();
|
|
return ctx->result;
|
|
}
|
|
|
|
/**
|
|
* keyring_search - Search the supplied keyring tree for a matching key
|
|
* @keyring: The root of the keyring tree to be searched.
|
|
* @type: The type of keyring we want to find.
|
|
* @description: The name of the keyring we want to find.
|
|
*
|
|
* As keyring_search_aux() above, but using the current task's credentials and
|
|
* type's default matching function and preferred search method.
|
|
*/
|
|
key_ref_t keyring_search(key_ref_t keyring,
|
|
struct key_type *type,
|
|
const char *description)
|
|
{
|
|
struct keyring_search_context ctx = {
|
|
.index_key.type = type,
|
|
.index_key.description = description,
|
|
.cred = current_cred(),
|
|
.match_data.cmp = key_default_cmp,
|
|
.match_data.raw_data = description,
|
|
.match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT,
|
|
.flags = KEYRING_SEARCH_DO_STATE_CHECK,
|
|
};
|
|
key_ref_t key;
|
|
int ret;
|
|
|
|
if (type->match_preparse) {
|
|
ret = type->match_preparse(&ctx.match_data);
|
|
if (ret < 0)
|
|
return ERR_PTR(ret);
|
|
}
|
|
|
|
key = keyring_search_aux(keyring, &ctx);
|
|
|
|
if (type->match_free)
|
|
type->match_free(&ctx.match_data);
|
|
return key;
|
|
}
|
|
EXPORT_SYMBOL(keyring_search);
|
|
|
|
static struct key_restriction *keyring_restriction_alloc(
|
|
key_restrict_link_func_t check)
|
|
{
|
|
struct key_restriction *keyres =
|
|
kzalloc(sizeof(struct key_restriction), GFP_KERNEL);
|
|
|
|
if (!keyres)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
keyres->check = check;
|
|
|
|
return keyres;
|
|
}
|
|
|
|
/*
|
|
* Semaphore to serialise restriction setup to prevent reference count
|
|
* cycles through restriction key pointers.
|
|
*/
|
|
static DECLARE_RWSEM(keyring_serialise_restrict_sem);
|
|
|
|
/*
|
|
* Check for restriction cycles that would prevent keyring garbage collection.
|
|
* keyring_serialise_restrict_sem must be held.
|
|
*/
|
|
static bool keyring_detect_restriction_cycle(const struct key *dest_keyring,
|
|
struct key_restriction *keyres)
|
|
{
|
|
while (keyres && keyres->key &&
|
|
keyres->key->type == &key_type_keyring) {
|
|
if (keyres->key == dest_keyring)
|
|
return true;
|
|
|
|
keyres = keyres->key->restrict_link;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
/**
|
|
* keyring_restrict - Look up and apply a restriction to a keyring
|
|
*
|
|
* @keyring: The keyring to be restricted
|
|
* @restriction: The restriction options to apply to the keyring
|
|
*/
|
|
int keyring_restrict(key_ref_t keyring_ref, const char *type,
|
|
const char *restriction)
|
|
{
|
|
struct key *keyring;
|
|
struct key_type *restrict_type = NULL;
|
|
struct key_restriction *restrict_link;
|
|
int ret = 0;
|
|
|
|
keyring = key_ref_to_ptr(keyring_ref);
|
|
key_check(keyring);
|
|
|
|
if (keyring->type != &key_type_keyring)
|
|
return -ENOTDIR;
|
|
|
|
if (!type) {
|
|
restrict_link = keyring_restriction_alloc(restrict_link_reject);
|
|
} else {
|
|
restrict_type = key_type_lookup(type);
|
|
|
|
if (IS_ERR(restrict_type))
|
|
return PTR_ERR(restrict_type);
|
|
|
|
if (!restrict_type->lookup_restriction) {
|
|
ret = -ENOENT;
|
|
goto error;
|
|
}
|
|
|
|
restrict_link = restrict_type->lookup_restriction(restriction);
|
|
}
|
|
|
|
if (IS_ERR(restrict_link)) {
|
|
ret = PTR_ERR(restrict_link);
|
|
goto error;
|
|
}
|
|
|
|
down_write(&keyring->sem);
|
|
down_write(&keyring_serialise_restrict_sem);
|
|
|
|
if (keyring->restrict_link)
|
|
ret = -EEXIST;
|
|
else if (keyring_detect_restriction_cycle(keyring, restrict_link))
|
|
ret = -EDEADLK;
|
|
else
|
|
keyring->restrict_link = restrict_link;
|
|
|
|
up_write(&keyring_serialise_restrict_sem);
|
|
up_write(&keyring->sem);
|
|
|
|
if (ret < 0) {
|
|
key_put(restrict_link->key);
|
|
kfree(restrict_link);
|
|
}
|
|
|
|
error:
|
|
if (restrict_type)
|
|
key_type_put(restrict_type);
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(keyring_restrict);
|
|
|
|
/*
|
|
* Search the given keyring for a key that might be updated.
|
|
*
|
|
* The caller must guarantee that the keyring is a keyring and that the
|
|
* permission is granted to modify the keyring as no check is made here. The
|
|
* caller must also hold a lock on the keyring semaphore.
|
|
*
|
|
* Returns a pointer to the found key with usage count incremented if
|
|
* successful and returns NULL if not found. Revoked and invalidated keys are
|
|
* skipped over.
|
|
*
|
|
* If successful, the possession indicator is propagated from the keyring ref
|
|
* to the returned key reference.
|
|
*/
|
|
key_ref_t find_key_to_update(key_ref_t keyring_ref,
|
|
const struct keyring_index_key *index_key)
|
|
{
|
|
struct key *keyring, *key;
|
|
const void *object;
|
|
|
|
keyring = key_ref_to_ptr(keyring_ref);
|
|
|
|
kenter("{%d},{%s,%s}",
|
|
keyring->serial, index_key->type->name, index_key->description);
|
|
|
|
object = assoc_array_find(&keyring->keys, &keyring_assoc_array_ops,
|
|
index_key);
|
|
|
|
if (object)
|
|
goto found;
|
|
|
|
kleave(" = NULL");
|
|
return NULL;
|
|
|
|
found:
|
|
key = keyring_ptr_to_key(object);
|
|
if (key->flags & ((1 << KEY_FLAG_INVALIDATED) |
|
|
(1 << KEY_FLAG_REVOKED))) {
|
|
kleave(" = NULL [x]");
|
|
return NULL;
|
|
}
|
|
__key_get(key);
|
|
kleave(" = {%d}", key->serial);
|
|
return make_key_ref(key, is_key_possessed(keyring_ref));
|
|
}
|
|
|
|
/*
|
|
* Find a keyring with the specified name.
|
|
*
|
|
* Only keyrings that have nonzero refcount, are not revoked, and are owned by a
|
|
* user in the current user namespace are considered. If @uid_keyring is %true,
|
|
* the keyring additionally must have been allocated as a user or user session
|
|
* keyring; otherwise, it must grant Search permission directly to the caller.
|
|
*
|
|
* Returns a pointer to the keyring with the keyring's refcount having being
|
|
* incremented on success. -ENOKEY is returned if a key could not be found.
|
|
*/
|
|
struct key *find_keyring_by_name(const char *name, bool uid_keyring)
|
|
{
|
|
struct key *keyring;
|
|
int bucket;
|
|
|
|
if (!name)
|
|
return ERR_PTR(-EINVAL);
|
|
|
|
bucket = keyring_hash(name);
|
|
|
|
read_lock(&keyring_name_lock);
|
|
|
|
if (keyring_name_hash[bucket].next) {
|
|
/* search this hash bucket for a keyring with a matching name
|
|
* that's readable and that hasn't been revoked */
|
|
list_for_each_entry(keyring,
|
|
&keyring_name_hash[bucket],
|
|
name_link
|
|
) {
|
|
if (!kuid_has_mapping(current_user_ns(), keyring->user->uid))
|
|
continue;
|
|
|
|
if (test_bit(KEY_FLAG_REVOKED, &keyring->flags))
|
|
continue;
|
|
|
|
if (strcmp(keyring->description, name) != 0)
|
|
continue;
|
|
|
|
if (uid_keyring) {
|
|
if (!test_bit(KEY_FLAG_UID_KEYRING,
|
|
&keyring->flags))
|
|
continue;
|
|
} else {
|
|
if (key_permission(make_key_ref(keyring, 0),
|
|
KEY_NEED_SEARCH) < 0)
|
|
continue;
|
|
}
|
|
|
|
/* we've got a match but we might end up racing with
|
|
* key_cleanup() if the keyring is currently 'dead'
|
|
* (ie. it has a zero usage count) */
|
|
if (!refcount_inc_not_zero(&keyring->usage))
|
|
continue;
|
|
keyring->last_used_at = ktime_get_real_seconds();
|
|
goto out;
|
|
}
|
|
}
|
|
|
|
keyring = ERR_PTR(-ENOKEY);
|
|
out:
|
|
read_unlock(&keyring_name_lock);
|
|
return keyring;
|
|
}
|
|
|
|
static int keyring_detect_cycle_iterator(const void *object,
|
|
void *iterator_data)
|
|
{
|
|
struct keyring_search_context *ctx = iterator_data;
|
|
const struct key *key = keyring_ptr_to_key(object);
|
|
|
|
kenter("{%d}", key->serial);
|
|
|
|
/* We might get a keyring with matching index-key that is nonetheless a
|
|
* different keyring. */
|
|
if (key != ctx->match_data.raw_data)
|
|
return 0;
|
|
|
|
ctx->result = ERR_PTR(-EDEADLK);
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* See if a cycle will will be created by inserting acyclic tree B in acyclic
|
|
* tree A at the topmost level (ie: as a direct child of A).
|
|
*
|
|
* Since we are adding B to A at the top level, checking for cycles should just
|
|
* be a matter of seeing if node A is somewhere in tree B.
|
|
*/
|
|
static int keyring_detect_cycle(struct key *A, struct key *B)
|
|
{
|
|
struct keyring_search_context ctx = {
|
|
.index_key = A->index_key,
|
|
.match_data.raw_data = A,
|
|
.match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT,
|
|
.iterator = keyring_detect_cycle_iterator,
|
|
.flags = (KEYRING_SEARCH_NO_STATE_CHECK |
|
|
KEYRING_SEARCH_NO_UPDATE_TIME |
|
|
KEYRING_SEARCH_NO_CHECK_PERM |
|
|
KEYRING_SEARCH_DETECT_TOO_DEEP),
|
|
};
|
|
|
|
rcu_read_lock();
|
|
search_nested_keyrings(B, &ctx);
|
|
rcu_read_unlock();
|
|
return PTR_ERR(ctx.result) == -EAGAIN ? 0 : PTR_ERR(ctx.result);
|
|
}
|
|
|
|
/*
|
|
* Preallocate memory so that a key can be linked into to a keyring.
|
|
*/
|
|
int __key_link_begin(struct key *keyring,
|
|
const struct keyring_index_key *index_key,
|
|
struct assoc_array_edit **_edit)
|
|
__acquires(&keyring->sem)
|
|
__acquires(&keyring_serialise_link_sem)
|
|
{
|
|
struct assoc_array_edit *edit;
|
|
int ret;
|
|
|
|
kenter("%d,%s,%s,",
|
|
keyring->serial, index_key->type->name, index_key->description);
|
|
|
|
BUG_ON(index_key->desc_len == 0);
|
|
|
|
if (keyring->type != &key_type_keyring)
|
|
return -ENOTDIR;
|
|
|
|
down_write(&keyring->sem);
|
|
|
|
ret = -EKEYREVOKED;
|
|
if (test_bit(KEY_FLAG_REVOKED, &keyring->flags))
|
|
goto error_krsem;
|
|
|
|
/* serialise link/link calls to prevent parallel calls causing a cycle
|
|
* when linking two keyring in opposite orders */
|
|
if (index_key->type == &key_type_keyring)
|
|
down_write(&keyring_serialise_link_sem);
|
|
|
|
/* Create an edit script that will insert/replace the key in the
|
|
* keyring tree.
|
|
*/
|
|
edit = assoc_array_insert(&keyring->keys,
|
|
&keyring_assoc_array_ops,
|
|
index_key,
|
|
NULL);
|
|
if (IS_ERR(edit)) {
|
|
ret = PTR_ERR(edit);
|
|
goto error_sem;
|
|
}
|
|
|
|
/* If we're not replacing a link in-place then we're going to need some
|
|
* extra quota.
|
|
*/
|
|
if (!edit->dead_leaf) {
|
|
ret = key_payload_reserve(keyring,
|
|
keyring->datalen + KEYQUOTA_LINK_BYTES);
|
|
if (ret < 0)
|
|
goto error_cancel;
|
|
}
|
|
|
|
*_edit = edit;
|
|
kleave(" = 0");
|
|
return 0;
|
|
|
|
error_cancel:
|
|
assoc_array_cancel_edit(edit);
|
|
error_sem:
|
|
if (index_key->type == &key_type_keyring)
|
|
up_write(&keyring_serialise_link_sem);
|
|
error_krsem:
|
|
up_write(&keyring->sem);
|
|
kleave(" = %d", ret);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Check already instantiated keys aren't going to be a problem.
|
|
*
|
|
* The caller must have called __key_link_begin(). Don't need to call this for
|
|
* keys that were created since __key_link_begin() was called.
|
|
*/
|
|
int __key_link_check_live_key(struct key *keyring, struct key *key)
|
|
{
|
|
if (key->type == &key_type_keyring)
|
|
/* check that we aren't going to create a cycle by linking one
|
|
* keyring to another */
|
|
return keyring_detect_cycle(keyring, key);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Link a key into to a keyring.
|
|
*
|
|
* Must be called with __key_link_begin() having being called. Discards any
|
|
* already extant link to matching key if there is one, so that each keyring
|
|
* holds at most one link to any given key of a particular type+description
|
|
* combination.
|
|
*/
|
|
void __key_link(struct key *key, struct assoc_array_edit **_edit)
|
|
{
|
|
__key_get(key);
|
|
assoc_array_insert_set_object(*_edit, keyring_key_to_ptr(key));
|
|
assoc_array_apply_edit(*_edit);
|
|
*_edit = NULL;
|
|
}
|
|
|
|
/*
|
|
* Finish linking a key into to a keyring.
|
|
*
|
|
* Must be called with __key_link_begin() having being called.
|
|
*/
|
|
void __key_link_end(struct key *keyring,
|
|
const struct keyring_index_key *index_key,
|
|
struct assoc_array_edit *edit)
|
|
__releases(&keyring->sem)
|
|
__releases(&keyring_serialise_link_sem)
|
|
{
|
|
BUG_ON(index_key->type == NULL);
|
|
kenter("%d,%s,", keyring->serial, index_key->type->name);
|
|
|
|
if (index_key->type == &key_type_keyring)
|
|
up_write(&keyring_serialise_link_sem);
|
|
|
|
if (edit) {
|
|
if (!edit->dead_leaf) {
|
|
key_payload_reserve(keyring,
|
|
keyring->datalen - KEYQUOTA_LINK_BYTES);
|
|
}
|
|
assoc_array_cancel_edit(edit);
|
|
}
|
|
up_write(&keyring->sem);
|
|
}
|
|
|
|
/*
|
|
* Check addition of keys to restricted keyrings.
|
|
*/
|
|
static int __key_link_check_restriction(struct key *keyring, struct key *key)
|
|
{
|
|
if (!keyring->restrict_link || !keyring->restrict_link->check)
|
|
return 0;
|
|
return keyring->restrict_link->check(keyring, key->type, &key->payload,
|
|
keyring->restrict_link->key);
|
|
}
|
|
|
|
/**
|
|
* key_link - Link a key to a keyring
|
|
* @keyring: The keyring to make the link in.
|
|
* @key: The key to link to.
|
|
*
|
|
* Make a link in a keyring to a key, such that the keyring holds a reference
|
|
* on that key and the key can potentially be found by searching that keyring.
|
|
*
|
|
* This function will write-lock the keyring's semaphore and will consume some
|
|
* of the user's key data quota to hold the link.
|
|
*
|
|
* Returns 0 if successful, -ENOTDIR if the keyring isn't a keyring,
|
|
* -EKEYREVOKED if the keyring has been revoked, -ENFILE if the keyring is
|
|
* full, -EDQUOT if there is insufficient key data quota remaining to add
|
|
* another link or -ENOMEM if there's insufficient memory.
|
|
*
|
|
* It is assumed that the caller has checked that it is permitted for a link to
|
|
* be made (the keyring should have Write permission and the key Link
|
|
* permission).
|
|
*/
|
|
int key_link(struct key *keyring, struct key *key)
|
|
{
|
|
struct assoc_array_edit *edit;
|
|
int ret;
|
|
|
|
kenter("{%d,%d}", keyring->serial, refcount_read(&keyring->usage));
|
|
|
|
key_check(keyring);
|
|
key_check(key);
|
|
|
|
ret = __key_link_begin(keyring, &key->index_key, &edit);
|
|
if (ret == 0) {
|
|
kdebug("begun {%d,%d}", keyring->serial, refcount_read(&keyring->usage));
|
|
ret = __key_link_check_restriction(keyring, key);
|
|
if (ret == 0)
|
|
ret = __key_link_check_live_key(keyring, key);
|
|
if (ret == 0)
|
|
__key_link(key, &edit);
|
|
__key_link_end(keyring, &key->index_key, edit);
|
|
}
|
|
|
|
kleave(" = %d {%d,%d}", ret, keyring->serial, refcount_read(&keyring->usage));
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(key_link);
|
|
|
|
/**
|
|
* key_unlink - Unlink the first link to a key from a keyring.
|
|
* @keyring: The keyring to remove the link from.
|
|
* @key: The key the link is to.
|
|
*
|
|
* Remove a link from a keyring to a key.
|
|
*
|
|
* This function will write-lock the keyring's semaphore.
|
|
*
|
|
* Returns 0 if successful, -ENOTDIR if the keyring isn't a keyring, -ENOENT if
|
|
* the key isn't linked to by the keyring or -ENOMEM if there's insufficient
|
|
* memory.
|
|
*
|
|
* It is assumed that the caller has checked that it is permitted for a link to
|
|
* be removed (the keyring should have Write permission; no permissions are
|
|
* required on the key).
|
|
*/
|
|
int key_unlink(struct key *keyring, struct key *key)
|
|
{
|
|
struct assoc_array_edit *edit;
|
|
int ret;
|
|
|
|
key_check(keyring);
|
|
key_check(key);
|
|
|
|
if (keyring->type != &key_type_keyring)
|
|
return -ENOTDIR;
|
|
|
|
down_write(&keyring->sem);
|
|
|
|
edit = assoc_array_delete(&keyring->keys, &keyring_assoc_array_ops,
|
|
&key->index_key);
|
|
if (IS_ERR(edit)) {
|
|
ret = PTR_ERR(edit);
|
|
goto error;
|
|
}
|
|
ret = -ENOENT;
|
|
if (edit == NULL)
|
|
goto error;
|
|
|
|
assoc_array_apply_edit(edit);
|
|
key_payload_reserve(keyring, keyring->datalen - KEYQUOTA_LINK_BYTES);
|
|
ret = 0;
|
|
|
|
error:
|
|
up_write(&keyring->sem);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(key_unlink);
|
|
|
|
/**
|
|
* keyring_clear - Clear a keyring
|
|
* @keyring: The keyring to clear.
|
|
*
|
|
* Clear the contents of the specified keyring.
|
|
*
|
|
* Returns 0 if successful or -ENOTDIR if the keyring isn't a keyring.
|
|
*/
|
|
int keyring_clear(struct key *keyring)
|
|
{
|
|
struct assoc_array_edit *edit;
|
|
int ret;
|
|
|
|
if (keyring->type != &key_type_keyring)
|
|
return -ENOTDIR;
|
|
|
|
down_write(&keyring->sem);
|
|
|
|
edit = assoc_array_clear(&keyring->keys, &keyring_assoc_array_ops);
|
|
if (IS_ERR(edit)) {
|
|
ret = PTR_ERR(edit);
|
|
} else {
|
|
if (edit)
|
|
assoc_array_apply_edit(edit);
|
|
key_payload_reserve(keyring, 0);
|
|
ret = 0;
|
|
}
|
|
|
|
up_write(&keyring->sem);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(keyring_clear);
|
|
|
|
/*
|
|
* Dispose of the links from a revoked keyring.
|
|
*
|
|
* This is called with the key sem write-locked.
|
|
*/
|
|
static void keyring_revoke(struct key *keyring)
|
|
{
|
|
struct assoc_array_edit *edit;
|
|
|
|
edit = assoc_array_clear(&keyring->keys, &keyring_assoc_array_ops);
|
|
if (!IS_ERR(edit)) {
|
|
if (edit)
|
|
assoc_array_apply_edit(edit);
|
|
key_payload_reserve(keyring, 0);
|
|
}
|
|
}
|
|
|
|
static bool keyring_gc_select_iterator(void *object, void *iterator_data)
|
|
{
|
|
struct key *key = keyring_ptr_to_key(object);
|
|
time64_t *limit = iterator_data;
|
|
|
|
if (key_is_dead(key, *limit))
|
|
return false;
|
|
key_get(key);
|
|
return true;
|
|
}
|
|
|
|
static int keyring_gc_check_iterator(const void *object, void *iterator_data)
|
|
{
|
|
const struct key *key = keyring_ptr_to_key(object);
|
|
time64_t *limit = iterator_data;
|
|
|
|
key_check(key);
|
|
return key_is_dead(key, *limit);
|
|
}
|
|
|
|
/*
|
|
* Garbage collect pointers from a keyring.
|
|
*
|
|
* Not called with any locks held. The keyring's key struct will not be
|
|
* deallocated under us as only our caller may deallocate it.
|
|
*/
|
|
void keyring_gc(struct key *keyring, time64_t limit)
|
|
{
|
|
int result;
|
|
|
|
kenter("%x{%s}", keyring->serial, keyring->description ?: "");
|
|
|
|
if (keyring->flags & ((1 << KEY_FLAG_INVALIDATED) |
|
|
(1 << KEY_FLAG_REVOKED)))
|
|
goto dont_gc;
|
|
|
|
/* scan the keyring looking for dead keys */
|
|
rcu_read_lock();
|
|
result = assoc_array_iterate(&keyring->keys,
|
|
keyring_gc_check_iterator, &limit);
|
|
rcu_read_unlock();
|
|
if (result == true)
|
|
goto do_gc;
|
|
|
|
dont_gc:
|
|
kleave(" [no gc]");
|
|
return;
|
|
|
|
do_gc:
|
|
down_write(&keyring->sem);
|
|
assoc_array_gc(&keyring->keys, &keyring_assoc_array_ops,
|
|
keyring_gc_select_iterator, &limit);
|
|
up_write(&keyring->sem);
|
|
kleave(" [gc]");
|
|
}
|
|
|
|
/*
|
|
* Garbage collect restriction pointers from a keyring.
|
|
*
|
|
* Keyring restrictions are associated with a key type, and must be cleaned
|
|
* up if the key type is unregistered. The restriction is altered to always
|
|
* reject additional keys so a keyring cannot be opened up by unregistering
|
|
* a key type.
|
|
*
|
|
* Not called with any keyring locks held. The keyring's key struct will not
|
|
* be deallocated under us as only our caller may deallocate it.
|
|
*
|
|
* The caller is required to hold key_types_sem and dead_type->sem. This is
|
|
* fulfilled by key_gc_keytype() holding the locks on behalf of
|
|
* key_garbage_collector(), which it invokes on a workqueue.
|
|
*/
|
|
void keyring_restriction_gc(struct key *keyring, struct key_type *dead_type)
|
|
{
|
|
struct key_restriction *keyres;
|
|
|
|
kenter("%x{%s}", keyring->serial, keyring->description ?: "");
|
|
|
|
/*
|
|
* keyring->restrict_link is only assigned at key allocation time
|
|
* or with the key type locked, so the only values that could be
|
|
* concurrently assigned to keyring->restrict_link are for key
|
|
* types other than dead_type. Given this, it's ok to check
|
|
* the key type before acquiring keyring->sem.
|
|
*/
|
|
if (!dead_type || !keyring->restrict_link ||
|
|
keyring->restrict_link->keytype != dead_type) {
|
|
kleave(" [no restriction gc]");
|
|
return;
|
|
}
|
|
|
|
/* Lock the keyring to ensure that a link is not in progress */
|
|
down_write(&keyring->sem);
|
|
|
|
keyres = keyring->restrict_link;
|
|
|
|
keyres->check = restrict_link_reject;
|
|
|
|
key_put(keyres->key);
|
|
keyres->key = NULL;
|
|
keyres->keytype = NULL;
|
|
|
|
up_write(&keyring->sem);
|
|
|
|
kleave(" [restriction gc]");
|
|
}
|