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1021 lines
24 KiB
1021 lines
24 KiB
/* keyring.c: keyring handling
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*
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* Copyright (C) 2004-5 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 <asm/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 set on how
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* 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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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 type definition
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*/
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static int keyring_instantiate(struct key *keyring,
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const void *data, size_t datalen);
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static int keyring_duplicate(struct key *keyring, const struct key *source);
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static int keyring_match(const struct key *keyring, const void *criterion);
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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 = sizeof(struct keyring_list),
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.instantiate = keyring_instantiate,
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.duplicate = keyring_duplicate,
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.match = keyring_match,
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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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/*
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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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DECLARE_RWSEM(keyring_serialise_link_sem);
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/*****************************************************************************/
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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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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->type_data.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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} /* end keyring_publish_name() */
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/*****************************************************************************/
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/*
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* initialise a keyring
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* - we object if we were given any data
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*/
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static int keyring_instantiate(struct key *keyring,
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const void *data, size_t datalen)
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{
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int ret;
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ret = -EINVAL;
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if (datalen == 0) {
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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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ret = 0;
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}
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return ret;
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} /* end keyring_instantiate() */
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/*****************************************************************************/
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/*
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* duplicate the list of subscribed keys from a source keyring into this one
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*/
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static int keyring_duplicate(struct key *keyring, const struct key *source)
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{
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struct keyring_list *sklist, *klist;
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unsigned max;
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size_t size;
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int loop, ret;
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const unsigned limit =
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(PAGE_SIZE - sizeof(*klist)) / sizeof(struct key *);
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ret = 0;
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/* find out how many keys are currently linked */
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rcu_read_lock();
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sklist = rcu_dereference(source->payload.subscriptions);
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max = 0;
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if (sklist)
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max = sklist->nkeys;
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rcu_read_unlock();
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/* allocate a new payload and stuff load with key links */
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if (max > 0) {
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BUG_ON(max > limit);
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max = (max + 3) & ~3;
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if (max > limit)
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max = limit;
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ret = -ENOMEM;
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size = sizeof(*klist) + sizeof(struct key *) * max;
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klist = kmalloc(size, GFP_KERNEL);
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if (!klist)
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goto error;
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/* set links */
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rcu_read_lock();
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sklist = rcu_dereference(source->payload.subscriptions);
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klist->maxkeys = max;
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klist->nkeys = sklist->nkeys;
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memcpy(klist->keys,
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sklist->keys,
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sklist->nkeys * sizeof(struct key *));
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for (loop = klist->nkeys - 1; loop >= 0; loop--)
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atomic_inc(&klist->keys[loop]->usage);
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rcu_read_unlock();
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rcu_assign_pointer(keyring->payload.subscriptions, klist);
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ret = 0;
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}
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error:
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return ret;
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} /* end keyring_duplicate() */
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/*****************************************************************************/
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/*
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* match keyrings on their name
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*/
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static int keyring_match(const struct key *keyring, const void *description)
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{
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return keyring->description &&
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strcmp(keyring->description, description) == 0;
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} /* end keyring_match() */
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/*****************************************************************************/
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/*
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* dispose of the data dangling from the corpse of a keyring
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*/
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static void keyring_destroy(struct key *keyring)
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{
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struct keyring_list *klist;
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int loop;
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if (keyring->description) {
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write_lock(&keyring_name_lock);
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if (keyring->type_data.link.next != NULL &&
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!list_empty(&keyring->type_data.link))
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list_del(&keyring->type_data.link);
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write_unlock(&keyring_name_lock);
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}
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klist = rcu_dereference(keyring->payload.subscriptions);
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if (klist) {
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for (loop = klist->nkeys - 1; loop >= 0; loop--)
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key_put(klist->keys[loop]);
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kfree(klist);
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}
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} /* end keyring_destroy() */
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/*****************************************************************************/
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/*
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* describe the keyring
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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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struct keyring_list *klist;
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if (keyring->description) {
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seq_puts(m, keyring->description);
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}
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else {
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seq_puts(m, "[anon]");
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}
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rcu_read_lock();
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klist = rcu_dereference(keyring->payload.subscriptions);
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if (klist)
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seq_printf(m, ": %u/%u", klist->nkeys, klist->maxkeys);
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else
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seq_puts(m, ": empty");
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rcu_read_unlock();
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} /* end keyring_describe() */
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/*****************************************************************************/
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/*
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* read a list of key IDs from the keyring's contents
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* - the keyring's semaphore is read-locked
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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_list *klist;
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struct key *key;
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size_t qty, tmp;
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int loop, ret;
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ret = 0;
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klist = rcu_dereference(keyring->payload.subscriptions);
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if (klist) {
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/* calculate how much data we could return */
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qty = klist->nkeys * sizeof(key_serial_t);
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if (buffer && buflen > 0) {
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if (buflen > qty)
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buflen = qty;
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/* copy the IDs of the subscribed keys into the
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* buffer */
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ret = -EFAULT;
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for (loop = 0; loop < klist->nkeys; loop++) {
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key = klist->keys[loop];
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tmp = sizeof(key_serial_t);
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if (tmp > buflen)
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tmp = buflen;
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if (copy_to_user(buffer,
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&key->serial,
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tmp) != 0)
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goto error;
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buflen -= tmp;
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if (buflen == 0)
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break;
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buffer += tmp;
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}
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}
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ret = qty;
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}
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error:
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return ret;
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} /* end keyring_read() */
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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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*/
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struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid,
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int not_in_quota, struct key *dest)
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{
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struct key *keyring;
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int ret;
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keyring = key_alloc(&key_type_keyring, description,
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uid, gid,
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(KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_ALL,
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not_in_quota);
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if (!IS_ERR(keyring)) {
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ret = key_instantiate_and_link(keyring, NULL, 0, dest, NULL);
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if (ret < 0) {
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key_put(keyring);
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keyring = ERR_PTR(ret);
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}
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}
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return keyring;
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} /* end keyring_alloc() */
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/*****************************************************************************/
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/*
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* search the supplied keyring tree for a key that matches the criterion
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* - perform a breadth-then-depth search up to the prescribed limit
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* - we only find keys on which we have search permission
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* - we use the supplied match function to see if the description (or other
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* feature of interest) matches
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* - we rely on RCU to prevent the keyring lists from disappearing on us
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* - we return -EAGAIN if we didn't find any matching key
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* - we return -ENOKEY if we only found negative matching keys
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* - we propagate the possession attribute from the keyring ref to the key ref
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*/
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key_ref_t keyring_search_aux(key_ref_t keyring_ref,
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struct task_struct *context,
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struct key_type *type,
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const void *description,
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key_match_func_t match)
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{
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struct {
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struct keyring_list *keylist;
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int kix;
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} stack[KEYRING_SEARCH_MAX_DEPTH];
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struct keyring_list *keylist;
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struct timespec now;
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unsigned long possessed;
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struct key *keyring, *key;
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key_ref_t key_ref;
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long err;
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int sp, kix;
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keyring = key_ref_to_ptr(keyring_ref);
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possessed = is_key_possessed(keyring_ref);
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key_check(keyring);
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/* top keyring must have search permission to begin the search */
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err = key_task_permission(keyring_ref, context, KEY_SEARCH);
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if (err < 0) {
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key_ref = ERR_PTR(err);
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goto error;
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}
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key_ref = ERR_PTR(-ENOTDIR);
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if (keyring->type != &key_type_keyring)
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goto error;
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rcu_read_lock();
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now = current_kernel_time();
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err = -EAGAIN;
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sp = 0;
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/* start processing a new keyring */
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descend:
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if (test_bit(KEY_FLAG_REVOKED, &keyring->flags))
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goto not_this_keyring;
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keylist = rcu_dereference(keyring->payload.subscriptions);
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if (!keylist)
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goto not_this_keyring;
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/* iterate through the keys in this keyring first */
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for (kix = 0; kix < keylist->nkeys; kix++) {
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key = keylist->keys[kix];
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/* ignore keys not of this type */
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if (key->type != type)
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continue;
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/* skip revoked keys and expired keys */
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if (test_bit(KEY_FLAG_REVOKED, &key->flags))
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continue;
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if (key->expiry && now.tv_sec >= key->expiry)
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continue;
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/* keys that don't match */
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if (!match(key, description))
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continue;
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/* key must have search permissions */
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if (key_task_permission(make_key_ref(key, possessed),
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context, KEY_SEARCH) < 0)
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continue;
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/* we set a different error code if we find a negative key */
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if (test_bit(KEY_FLAG_NEGATIVE, &key->flags)) {
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err = -ENOKEY;
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continue;
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}
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goto found;
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}
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/* search through the keyrings nested in this one */
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kix = 0;
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ascend:
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for (; kix < keylist->nkeys; kix++) {
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key = keylist->keys[kix];
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if (key->type != &key_type_keyring)
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continue;
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/* recursively search nested keyrings
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* - only search keyrings for which we have search permission
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*/
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if (sp >= KEYRING_SEARCH_MAX_DEPTH)
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continue;
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if (!key_task_permission(make_key_ref(key, possessed),
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context, KEY_SEARCH) < 0)
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continue;
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/* stack the current position */
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stack[sp].keylist = keylist;
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stack[sp].kix = kix;
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sp++;
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/* begin again with the new keyring */
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keyring = key;
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goto descend;
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}
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/* the keyring we're looking at was disqualified or didn't contain a
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* matching key */
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not_this_keyring:
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if (sp > 0) {
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/* resume the processing of a keyring higher up in the tree */
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sp--;
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keylist = stack[sp].keylist;
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kix = stack[sp].kix + 1;
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goto ascend;
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}
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key_ref = ERR_PTR(err);
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goto error_2;
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/* we found a viable match */
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found:
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atomic_inc(&key->usage);
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key_check(key);
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key_ref = make_key_ref(key, possessed);
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error_2:
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rcu_read_unlock();
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error:
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return key_ref;
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} /* end keyring_search_aux() */
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/*****************************************************************************/
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/*
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* search the supplied keyring tree for a key that matches the criterion
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* - perform a breadth-then-depth search up to the prescribed limit
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* - we only find keys on which we have search permission
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* - we readlock the keyrings as we search down the tree
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* - we return -EAGAIN if we didn't find any matching key
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* - we return -ENOKEY if we only found negative matching keys
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*/
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key_ref_t keyring_search(key_ref_t keyring,
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struct key_type *type,
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const char *description)
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{
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if (!type->match)
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return ERR_PTR(-ENOKEY);
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return keyring_search_aux(keyring, current,
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type, description, type->match);
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} /* end keyring_search() */
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EXPORT_SYMBOL(keyring_search);
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/*****************************************************************************/
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/*
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* search the given keyring only (no recursion)
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* - keyring must be locked by caller
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*/
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key_ref_t __keyring_search_one(key_ref_t keyring_ref,
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const struct key_type *ktype,
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const char *description,
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key_perm_t perm)
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{
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struct keyring_list *klist;
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unsigned long possessed;
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struct key *keyring, *key;
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int loop;
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keyring = key_ref_to_ptr(keyring_ref);
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possessed = is_key_possessed(keyring_ref);
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rcu_read_lock();
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klist = rcu_dereference(keyring->payload.subscriptions);
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if (klist) {
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for (loop = 0; loop < klist->nkeys; loop++) {
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key = klist->keys[loop];
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if (key->type == ktype &&
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(!key->type->match ||
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key->type->match(key, description)) &&
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key_permission(make_key_ref(key, possessed),
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perm) < 0 &&
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!test_bit(KEY_FLAG_REVOKED, &key->flags)
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)
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goto found;
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}
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}
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rcu_read_unlock();
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return ERR_PTR(-ENOKEY);
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found:
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atomic_inc(&key->usage);
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rcu_read_unlock();
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return make_key_ref(key, possessed);
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} /* end __keyring_search_one() */
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/*****************************************************************************/
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/*
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* search for an instantiation authorisation key matching a target key
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* - the RCU read lock must be held by the caller
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* - a target_id of zero specifies any valid token
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*/
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struct key *keyring_search_instkey(struct key *keyring,
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key_serial_t target_id)
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{
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struct request_key_auth *rka;
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struct keyring_list *klist;
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struct key *instkey;
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int loop;
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klist = rcu_dereference(keyring->payload.subscriptions);
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if (klist) {
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for (loop = 0; loop < klist->nkeys; loop++) {
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instkey = klist->keys[loop];
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if (instkey->type != &key_type_request_key_auth)
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|
continue;
|
|
|
|
rka = instkey->payload.data;
|
|
if (target_id && rka->target_key->serial != target_id)
|
|
continue;
|
|
|
|
/* the auth key is revoked during instantiation */
|
|
if (!test_bit(KEY_FLAG_REVOKED, &instkey->flags))
|
|
goto found;
|
|
|
|
instkey = ERR_PTR(-EKEYREVOKED);
|
|
goto error;
|
|
}
|
|
}
|
|
|
|
instkey = ERR_PTR(-EACCES);
|
|
goto error;
|
|
|
|
found:
|
|
atomic_inc(&instkey->usage);
|
|
error:
|
|
return instkey;
|
|
|
|
} /* end keyring_search_instkey() */
|
|
|
|
/*****************************************************************************/
|
|
/*
|
|
* find a keyring with the specified name
|
|
* - all named keyrings are searched
|
|
* - only find keyrings with search permission for the process
|
|
* - only find keyrings with a serial number greater than the one specified
|
|
*/
|
|
struct key *find_keyring_by_name(const char *name, key_serial_t bound)
|
|
{
|
|
struct key *keyring;
|
|
int bucket;
|
|
|
|
keyring = ERR_PTR(-EINVAL);
|
|
if (!name)
|
|
goto error;
|
|
|
|
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],
|
|
type_data.link
|
|
) {
|
|
if (test_bit(KEY_FLAG_REVOKED, &keyring->flags))
|
|
continue;
|
|
|
|
if (strcmp(keyring->description, name) != 0)
|
|
continue;
|
|
|
|
if (!key_permission(make_key_ref(keyring, 0),
|
|
KEY_SEARCH) < 0)
|
|
continue;
|
|
|
|
/* found a potential candidate, but we still need to
|
|
* check the serial number */
|
|
if (keyring->serial <= bound)
|
|
continue;
|
|
|
|
/* we've got a match */
|
|
atomic_inc(&keyring->usage);
|
|
read_unlock(&keyring_name_lock);
|
|
goto error;
|
|
}
|
|
}
|
|
|
|
read_unlock(&keyring_name_lock);
|
|
keyring = ERR_PTR(-ENOKEY);
|
|
|
|
error:
|
|
return keyring;
|
|
|
|
} /* end find_keyring_by_name() */
|
|
|
|
/*****************************************************************************/
|
|
/*
|
|
* 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 {
|
|
struct keyring_list *keylist;
|
|
int kix;
|
|
} stack[KEYRING_SEARCH_MAX_DEPTH];
|
|
|
|
struct keyring_list *keylist;
|
|
struct key *subtree, *key;
|
|
int sp, kix, ret;
|
|
|
|
rcu_read_lock();
|
|
|
|
ret = -EDEADLK;
|
|
if (A == B)
|
|
goto cycle_detected;
|
|
|
|
subtree = B;
|
|
sp = 0;
|
|
|
|
/* start processing a new keyring */
|
|
descend:
|
|
if (test_bit(KEY_FLAG_REVOKED, &subtree->flags))
|
|
goto not_this_keyring;
|
|
|
|
keylist = rcu_dereference(subtree->payload.subscriptions);
|
|
if (!keylist)
|
|
goto not_this_keyring;
|
|
kix = 0;
|
|
|
|
ascend:
|
|
/* iterate through the remaining keys in this keyring */
|
|
for (; kix < keylist->nkeys; kix++) {
|
|
key = keylist->keys[kix];
|
|
|
|
if (key == A)
|
|
goto cycle_detected;
|
|
|
|
/* recursively check nested keyrings */
|
|
if (key->type == &key_type_keyring) {
|
|
if (sp >= KEYRING_SEARCH_MAX_DEPTH)
|
|
goto too_deep;
|
|
|
|
/* stack the current position */
|
|
stack[sp].keylist = keylist;
|
|
stack[sp].kix = kix;
|
|
sp++;
|
|
|
|
/* begin again with the new keyring */
|
|
subtree = key;
|
|
goto descend;
|
|
}
|
|
}
|
|
|
|
/* the keyring we're looking at was disqualified or didn't contain a
|
|
* matching key */
|
|
not_this_keyring:
|
|
if (sp > 0) {
|
|
/* resume the checking of a keyring higher up in the tree */
|
|
sp--;
|
|
keylist = stack[sp].keylist;
|
|
kix = stack[sp].kix + 1;
|
|
goto ascend;
|
|
}
|
|
|
|
ret = 0; /* no cycles detected */
|
|
|
|
error:
|
|
rcu_read_unlock();
|
|
return ret;
|
|
|
|
too_deep:
|
|
ret = -ELOOP;
|
|
goto error;
|
|
|
|
cycle_detected:
|
|
ret = -EDEADLK;
|
|
goto error;
|
|
|
|
} /* end keyring_detect_cycle() */
|
|
|
|
/*****************************************************************************/
|
|
/*
|
|
* dispose of a keyring list after the RCU grace period
|
|
*/
|
|
static void keyring_link_rcu_disposal(struct rcu_head *rcu)
|
|
{
|
|
struct keyring_list *klist =
|
|
container_of(rcu, struct keyring_list, rcu);
|
|
|
|
kfree(klist);
|
|
|
|
} /* end keyring_link_rcu_disposal() */
|
|
|
|
/*****************************************************************************/
|
|
/*
|
|
* link a key into to a keyring
|
|
* - must be called with the keyring's semaphore write-locked
|
|
*/
|
|
int __key_link(struct key *keyring, struct key *key)
|
|
{
|
|
struct keyring_list *klist, *nklist;
|
|
unsigned max;
|
|
size_t size;
|
|
int ret;
|
|
|
|
ret = -EKEYREVOKED;
|
|
if (test_bit(KEY_FLAG_REVOKED, &keyring->flags))
|
|
goto error;
|
|
|
|
ret = -ENOTDIR;
|
|
if (keyring->type != &key_type_keyring)
|
|
goto error;
|
|
|
|
/* serialise link/link calls to prevent parallel calls causing a
|
|
* cycle when applied to two keyring in opposite orders */
|
|
down_write(&keyring_serialise_link_sem);
|
|
|
|
/* check that we aren't going to create a cycle adding one keyring to
|
|
* another */
|
|
if (key->type == &key_type_keyring) {
|
|
ret = keyring_detect_cycle(keyring, key);
|
|
if (ret < 0)
|
|
goto error2;
|
|
}
|
|
|
|
/* check that we aren't going to overrun the user's quota */
|
|
ret = key_payload_reserve(keyring,
|
|
keyring->datalen + KEYQUOTA_LINK_BYTES);
|
|
if (ret < 0)
|
|
goto error2;
|
|
|
|
klist = keyring->payload.subscriptions;
|
|
|
|
if (klist && klist->nkeys < klist->maxkeys) {
|
|
/* there's sufficient slack space to add directly */
|
|
atomic_inc(&key->usage);
|
|
|
|
klist->keys[klist->nkeys] = key;
|
|
smp_wmb();
|
|
klist->nkeys++;
|
|
smp_wmb();
|
|
|
|
ret = 0;
|
|
}
|
|
else {
|
|
/* grow the key list */
|
|
max = 4;
|
|
if (klist)
|
|
max += klist->maxkeys;
|
|
|
|
ret = -ENFILE;
|
|
if (max > 65535)
|
|
goto error3;
|
|
size = sizeof(*klist) + sizeof(struct key *) * max;
|
|
if (size > PAGE_SIZE)
|
|
goto error3;
|
|
|
|
ret = -ENOMEM;
|
|
nklist = kmalloc(size, GFP_KERNEL);
|
|
if (!nklist)
|
|
goto error3;
|
|
nklist->maxkeys = max;
|
|
nklist->nkeys = 0;
|
|
|
|
if (klist) {
|
|
nklist->nkeys = klist->nkeys;
|
|
memcpy(nklist->keys,
|
|
klist->keys,
|
|
sizeof(struct key *) * klist->nkeys);
|
|
}
|
|
|
|
/* add the key into the new space */
|
|
atomic_inc(&key->usage);
|
|
nklist->keys[nklist->nkeys++] = key;
|
|
|
|
rcu_assign_pointer(keyring->payload.subscriptions, nklist);
|
|
|
|
/* dispose of the old keyring list */
|
|
if (klist)
|
|
call_rcu(&klist->rcu, keyring_link_rcu_disposal);
|
|
|
|
ret = 0;
|
|
}
|
|
|
|
error2:
|
|
up_write(&keyring_serialise_link_sem);
|
|
error:
|
|
return ret;
|
|
|
|
error3:
|
|
/* undo the quota changes */
|
|
key_payload_reserve(keyring,
|
|
keyring->datalen - KEYQUOTA_LINK_BYTES);
|
|
goto error2;
|
|
|
|
} /* end __key_link() */
|
|
|
|
/*****************************************************************************/
|
|
/*
|
|
* link a key to a keyring
|
|
*/
|
|
int key_link(struct key *keyring, struct key *key)
|
|
{
|
|
int ret;
|
|
|
|
key_check(keyring);
|
|
key_check(key);
|
|
|
|
down_write(&keyring->sem);
|
|
ret = __key_link(keyring, key);
|
|
up_write(&keyring->sem);
|
|
|
|
return ret;
|
|
|
|
} /* end key_link() */
|
|
|
|
EXPORT_SYMBOL(key_link);
|
|
|
|
/*****************************************************************************/
|
|
/*
|
|
* dispose of a keyring list after the RCU grace period, freeing the unlinked
|
|
* key
|
|
*/
|
|
static void keyring_unlink_rcu_disposal(struct rcu_head *rcu)
|
|
{
|
|
struct keyring_list *klist =
|
|
container_of(rcu, struct keyring_list, rcu);
|
|
|
|
key_put(klist->keys[klist->delkey]);
|
|
kfree(klist);
|
|
|
|
} /* end keyring_unlink_rcu_disposal() */
|
|
|
|
/*****************************************************************************/
|
|
/*
|
|
* unlink the first link to a key from a keyring
|
|
*/
|
|
int key_unlink(struct key *keyring, struct key *key)
|
|
{
|
|
struct keyring_list *klist, *nklist;
|
|
int loop, ret;
|
|
|
|
key_check(keyring);
|
|
key_check(key);
|
|
|
|
ret = -ENOTDIR;
|
|
if (keyring->type != &key_type_keyring)
|
|
goto error;
|
|
|
|
down_write(&keyring->sem);
|
|
|
|
klist = keyring->payload.subscriptions;
|
|
if (klist) {
|
|
/* search the keyring for the key */
|
|
for (loop = 0; loop < klist->nkeys; loop++)
|
|
if (klist->keys[loop] == key)
|
|
goto key_is_present;
|
|
}
|
|
|
|
up_write(&keyring->sem);
|
|
ret = -ENOENT;
|
|
goto error;
|
|
|
|
key_is_present:
|
|
/* we need to copy the key list for RCU purposes */
|
|
nklist = kmalloc(sizeof(*klist) +
|
|
sizeof(struct key *) * klist->maxkeys,
|
|
GFP_KERNEL);
|
|
if (!nklist)
|
|
goto nomem;
|
|
nklist->maxkeys = klist->maxkeys;
|
|
nklist->nkeys = klist->nkeys - 1;
|
|
|
|
if (loop > 0)
|
|
memcpy(&nklist->keys[0],
|
|
&klist->keys[0],
|
|
loop * sizeof(struct key *));
|
|
|
|
if (loop < nklist->nkeys)
|
|
memcpy(&nklist->keys[loop],
|
|
&klist->keys[loop + 1],
|
|
(nklist->nkeys - loop) * sizeof(struct key *));
|
|
|
|
/* adjust the user's quota */
|
|
key_payload_reserve(keyring,
|
|
keyring->datalen - KEYQUOTA_LINK_BYTES);
|
|
|
|
rcu_assign_pointer(keyring->payload.subscriptions, nklist);
|
|
|
|
up_write(&keyring->sem);
|
|
|
|
/* schedule for later cleanup */
|
|
klist->delkey = loop;
|
|
call_rcu(&klist->rcu, keyring_unlink_rcu_disposal);
|
|
|
|
ret = 0;
|
|
|
|
error:
|
|
return ret;
|
|
nomem:
|
|
ret = -ENOMEM;
|
|
up_write(&keyring->sem);
|
|
goto error;
|
|
|
|
} /* end key_unlink() */
|
|
|
|
EXPORT_SYMBOL(key_unlink);
|
|
|
|
/*****************************************************************************/
|
|
/*
|
|
* dispose of a keyring list after the RCU grace period, releasing the keys it
|
|
* links to
|
|
*/
|
|
static void keyring_clear_rcu_disposal(struct rcu_head *rcu)
|
|
{
|
|
struct keyring_list *klist;
|
|
int loop;
|
|
|
|
klist = container_of(rcu, struct keyring_list, rcu);
|
|
|
|
for (loop = klist->nkeys - 1; loop >= 0; loop--)
|
|
key_put(klist->keys[loop]);
|
|
|
|
kfree(klist);
|
|
|
|
} /* end keyring_clear_rcu_disposal() */
|
|
|
|
/*****************************************************************************/
|
|
/*
|
|
* clear the specified process keyring
|
|
* - implements keyctl(KEYCTL_CLEAR)
|
|
*/
|
|
int keyring_clear(struct key *keyring)
|
|
{
|
|
struct keyring_list *klist;
|
|
int ret;
|
|
|
|
ret = -ENOTDIR;
|
|
if (keyring->type == &key_type_keyring) {
|
|
/* detach the pointer block with the locks held */
|
|
down_write(&keyring->sem);
|
|
|
|
klist = keyring->payload.subscriptions;
|
|
if (klist) {
|
|
/* adjust the quota */
|
|
key_payload_reserve(keyring,
|
|
sizeof(struct keyring_list));
|
|
|
|
rcu_assign_pointer(keyring->payload.subscriptions,
|
|
NULL);
|
|
}
|
|
|
|
up_write(&keyring->sem);
|
|
|
|
/* free the keys after the locks have been dropped */
|
|
if (klist)
|
|
call_rcu(&klist->rcu, keyring_clear_rcu_disposal);
|
|
|
|
ret = 0;
|
|
}
|
|
|
|
return ret;
|
|
|
|
} /* end keyring_clear() */
|
|
|
|
EXPORT_SYMBOL(keyring_clear);
|
|
|