Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
This commit is contained in:
Linus Torvalds
895
security/keys/keyring.c
Normal file
895
security/keys/keyring.c
Normal file
@@ -0,0 +1,895 @@
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/* keyring.c: keyring handling
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*
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* Copyright (C) 2004 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/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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sklist = source->payload.subscriptions;
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if (sklist && sklist->nkeys > 0) {
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max = sklist->nkeys;
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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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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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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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list_del(&keyring->type_data.link);
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write_unlock(&keyring_name_lock);
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}
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klist = 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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klist = 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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} /* 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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*/
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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 = 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, KEY_USR_ALL, not_in_quota);
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if (!IS_ERR(keyring)) {
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ret = key_instantiate_and_link(keyring, NULL, 0, dest);
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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 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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struct key *keyring_search_aux(struct key *keyring,
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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 key *keyring;
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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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struct key *key;
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long err;
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int sp, psp, kix;
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key_check(keyring);
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||||
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||||
/* top keyring must have search permission to begin the search */
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||||
key = ERR_PTR(-EACCES);
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if (!key_permission(keyring, KEY_SEARCH))
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||||
goto error;
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||||
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||||
key = ERR_PTR(-ENOTDIR);
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||||
if (keyring->type != &key_type_keyring)
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||||
goto error;
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||||
|
||||
now = current_kernel_time();
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||||
err = -EAGAIN;
|
||||
sp = 0;
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||||
|
||||
/* start processing a new keyring */
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||||
descend:
|
||||
read_lock(&keyring->lock);
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||||
if (keyring->flags & KEY_FLAG_REVOKED)
|
||||
goto not_this_keyring;
|
||||
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||||
keylist = keyring->payload.subscriptions;
|
||||
if (!keylist)
|
||||
goto not_this_keyring;
|
||||
|
||||
/* iterate through the keys in this keyring first */
|
||||
for (kix = 0; kix < keylist->nkeys; kix++) {
|
||||
key = keylist->keys[kix];
|
||||
|
||||
/* ignore keys not of this type */
|
||||
if (key->type != type)
|
||||
continue;
|
||||
|
||||
/* skip revoked keys and expired keys */
|
||||
if (key->flags & KEY_FLAG_REVOKED)
|
||||
continue;
|
||||
|
||||
if (key->expiry && now.tv_sec >= key->expiry)
|
||||
continue;
|
||||
|
||||
/* keys that don't match */
|
||||
if (!match(key, description))
|
||||
continue;
|
||||
|
||||
/* key must have search permissions */
|
||||
if (!key_permission(key, KEY_SEARCH))
|
||||
continue;
|
||||
|
||||
/* we set a different error code if we find a negative key */
|
||||
if (key->flags & KEY_FLAG_NEGATIVE) {
|
||||
err = -ENOKEY;
|
||||
continue;
|
||||
}
|
||||
|
||||
goto found;
|
||||
}
|
||||
|
||||
/* search through the keyrings nested in this one */
|
||||
kix = 0;
|
||||
ascend:
|
||||
while (kix < keylist->nkeys) {
|
||||
key = keylist->keys[kix];
|
||||
if (key->type != &key_type_keyring)
|
||||
goto next;
|
||||
|
||||
/* recursively search nested keyrings
|
||||
* - only search keyrings for which we have search permission
|
||||
*/
|
||||
if (sp >= KEYRING_SEARCH_MAX_DEPTH)
|
||||
goto next;
|
||||
|
||||
if (!key_permission(key, KEY_SEARCH))
|
||||
goto next;
|
||||
|
||||
/* evade loops in the keyring tree */
|
||||
for (psp = 0; psp < sp; psp++)
|
||||
if (stack[psp].keyring == keyring)
|
||||
goto next;
|
||||
|
||||
/* stack the current position */
|
||||
stack[sp].keyring = keyring;
|
||||
stack[sp].kix = kix;
|
||||
sp++;
|
||||
|
||||
/* begin again with the new keyring */
|
||||
keyring = key;
|
||||
goto descend;
|
||||
|
||||
next:
|
||||
kix++;
|
||||
}
|
||||
|
||||
/* the keyring we're looking at was disqualified or didn't contain a
|
||||
* matching key */
|
||||
not_this_keyring:
|
||||
read_unlock(&keyring->lock);
|
||||
|
||||
if (sp > 0) {
|
||||
/* resume the processing of a keyring higher up in the tree */
|
||||
sp--;
|
||||
keyring = stack[sp].keyring;
|
||||
keylist = keyring->payload.subscriptions;
|
||||
kix = stack[sp].kix + 1;
|
||||
goto ascend;
|
||||
}
|
||||
|
||||
key = ERR_PTR(err);
|
||||
goto error;
|
||||
|
||||
/* we found a viable match */
|
||||
found:
|
||||
atomic_inc(&key->usage);
|
||||
read_unlock(&keyring->lock);
|
||||
|
||||
/* unwind the keyring stack */
|
||||
while (sp > 0) {
|
||||
sp--;
|
||||
read_unlock(&stack[sp].keyring->lock);
|
||||
}
|
||||
|
||||
key_check(key);
|
||||
error:
|
||||
return key;
|
||||
|
||||
} /* end keyring_search_aux() */
|
||||
|
||||
/*****************************************************************************/
|
||||
/*
|
||||
* search the supplied keyring tree for a key that matches the criterion
|
||||
* - perform a breadth-then-depth search up to the prescribed limit
|
||||
* - we only find keys on which we have search permission
|
||||
* - we readlock the keyrings as we search down the tree
|
||||
* - we return -EAGAIN if we didn't find any matching key
|
||||
* - we return -ENOKEY if we only found negative matching keys
|
||||
*/
|
||||
struct key *keyring_search(struct key *keyring,
|
||||
struct key_type *type,
|
||||
const char *description)
|
||||
{
|
||||
return keyring_search_aux(keyring, type, description, type->match);
|
||||
|
||||
} /* end keyring_search() */
|
||||
|
||||
EXPORT_SYMBOL(keyring_search);
|
||||
|
||||
/*****************************************************************************/
|
||||
/*
|
||||
* search the given keyring only (no recursion)
|
||||
* - keyring must be locked by caller
|
||||
*/
|
||||
struct key *__keyring_search_one(struct key *keyring,
|
||||
const struct key_type *ktype,
|
||||
const char *description,
|
||||
key_perm_t perm)
|
||||
{
|
||||
struct keyring_list *klist;
|
||||
struct key *key;
|
||||
int loop;
|
||||
|
||||
klist = keyring->payload.subscriptions;
|
||||
if (klist) {
|
||||
for (loop = 0; loop < klist->nkeys; loop++) {
|
||||
key = klist->keys[loop];
|
||||
|
||||
if (key->type == ktype &&
|
||||
key->type->match(key, description) &&
|
||||
key_permission(key, perm) &&
|
||||
!(key->flags & KEY_FLAG_REVOKED)
|
||||
)
|
||||
goto found;
|
||||
}
|
||||
}
|
||||
|
||||
key = ERR_PTR(-ENOKEY);
|
||||
goto error;
|
||||
|
||||
found:
|
||||
atomic_inc(&key->usage);
|
||||
error:
|
||||
return key;
|
||||
|
||||
} /* end __keyring_search_one() */
|
||||
|
||||
/*****************************************************************************/
|
||||
/*
|
||||
* 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 (keyring->flags & KEY_FLAG_REVOKED)
|
||||
continue;
|
||||
|
||||
if (strcmp(keyring->description, name) != 0)
|
||||
continue;
|
||||
|
||||
if (!key_permission(keyring, KEY_SEARCH))
|
||||
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 key *subtree;
|
||||
int kix;
|
||||
} stack[KEYRING_SEARCH_MAX_DEPTH];
|
||||
|
||||
struct keyring_list *keylist;
|
||||
struct key *subtree, *key;
|
||||
int sp, kix, ret;
|
||||
|
||||
ret = -EDEADLK;
|
||||
if (A == B)
|
||||
goto error;
|
||||
|
||||
subtree = B;
|
||||
sp = 0;
|
||||
|
||||
/* start processing a new keyring */
|
||||
descend:
|
||||
read_lock(&subtree->lock);
|
||||
if (subtree->flags & KEY_FLAG_REVOKED)
|
||||
goto not_this_keyring;
|
||||
|
||||
keylist = 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].subtree = subtree;
|
||||
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:
|
||||
read_unlock(&subtree->lock);
|
||||
|
||||
if (sp > 0) {
|
||||
/* resume the checking of a keyring higher up in the tree */
|
||||
sp--;
|
||||
subtree = stack[sp].subtree;
|
||||
keylist = subtree->payload.subscriptions;
|
||||
kix = stack[sp].kix + 1;
|
||||
goto ascend;
|
||||
}
|
||||
|
||||
ret = 0; /* no cycles detected */
|
||||
|
||||
error:
|
||||
return ret;
|
||||
|
||||
too_deep:
|
||||
ret = -ELOOP;
|
||||
goto error_unwind;
|
||||
cycle_detected:
|
||||
ret = -EDEADLK;
|
||||
error_unwind:
|
||||
read_unlock(&subtree->lock);
|
||||
|
||||
/* unwind the keyring stack */
|
||||
while (sp > 0) {
|
||||
sp--;
|
||||
read_unlock(&stack[sp].subtree->lock);
|
||||
}
|
||||
|
||||
goto error;
|
||||
|
||||
} /* end keyring_detect_cycle() */
|
||||
|
||||
/*****************************************************************************/
|
||||
/*
|
||||
* link a key into to a keyring
|
||||
* - must be called with the keyring's semaphore held
|
||||
*/
|
||||
int __key_link(struct key *keyring, struct key *key)
|
||||
{
|
||||
struct keyring_list *klist, *nklist;
|
||||
unsigned max;
|
||||
size_t size;
|
||||
int ret;
|
||||
|
||||
ret = -EKEYREVOKED;
|
||||
if (keyring->flags & KEY_FLAG_REVOKED)
|
||||
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);
|
||||
|
||||
write_lock(&keyring->lock);
|
||||
klist->keys[klist->nkeys++] = key;
|
||||
write_unlock(&keyring->lock);
|
||||
|
||||
ret = 0;
|
||||
}
|
||||
else {
|
||||
/* grow the key list */
|
||||
max = 4;
|
||||
if (klist)
|
||||
max += klist->maxkeys;
|
||||
|
||||
ret = -ENFILE;
|
||||
size = sizeof(*klist) + sizeof(*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);
|
||||
|
||||
write_lock(&keyring->lock);
|
||||
keyring->payload.subscriptions = nklist;
|
||||
nklist->keys[nklist->nkeys++] = key;
|
||||
write_unlock(&keyring->lock);
|
||||
|
||||
/* dispose of the old keyring list */
|
||||
kfree(klist);
|
||||
|
||||
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);
|
||||
|
||||
/*****************************************************************************/
|
||||
/*
|
||||
* unlink the first link to a key from a keyring
|
||||
*/
|
||||
int key_unlink(struct key *keyring, struct key *key)
|
||||
{
|
||||
struct keyring_list *klist;
|
||||
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:
|
||||
/* adjust the user's quota */
|
||||
key_payload_reserve(keyring,
|
||||
keyring->datalen - KEYQUOTA_LINK_BYTES);
|
||||
|
||||
/* shuffle down the key pointers
|
||||
* - it might be worth shrinking the allocated memory, but that runs
|
||||
* the risk of ENOMEM as we would have to copy
|
||||
*/
|
||||
write_lock(&keyring->lock);
|
||||
|
||||
klist->nkeys--;
|
||||
if (loop < klist->nkeys)
|
||||
memcpy(&klist->keys[loop],
|
||||
&klist->keys[loop + 1],
|
||||
(klist->nkeys - loop) * sizeof(struct key *));
|
||||
|
||||
write_unlock(&keyring->lock);
|
||||
|
||||
up_write(&keyring->sem);
|
||||
key_put(key);
|
||||
ret = 0;
|
||||
|
||||
error:
|
||||
return ret;
|
||||
|
||||
} /* end key_unlink() */
|
||||
|
||||
EXPORT_SYMBOL(key_unlink);
|
||||
|
||||
/*****************************************************************************/
|
||||
/*
|
||||
* clear the specified process keyring
|
||||
* - implements keyctl(KEYCTL_CLEAR)
|
||||
*/
|
||||
int keyring_clear(struct key *keyring)
|
||||
{
|
||||
struct keyring_list *klist;
|
||||
int loop, 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));
|
||||
|
||||
write_lock(&keyring->lock);
|
||||
keyring->payload.subscriptions = NULL;
|
||||
write_unlock(&keyring->lock);
|
||||
}
|
||||
|
||||
up_write(&keyring->sem);
|
||||
|
||||
/* free the keys after the locks have been dropped */
|
||||
if (klist) {
|
||||
for (loop = klist->nkeys - 1; loop >= 0; loop--)
|
||||
key_put(klist->keys[loop]);
|
||||
|
||||
kfree(klist);
|
||||
}
|
||||
|
||||
ret = 0;
|
||||
}
|
||||
|
||||
return ret;
|
||||
|
||||
} /* end keyring_clear() */
|
||||
|
||||
EXPORT_SYMBOL(keyring_clear);
|
||||
Reference in New Issue
Block a user