-/* keyring.c: keyring handling
+/* Keyring handling
*
- * Copyright (C) 2004-5 Red Hat, Inc. All Rights Reserved.
+ * Copyright (C) 2004-2005, 2008 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
#include <linux/security.h>
#include <linux/seq_file.h>
#include <linux/err.h>
+#include <keys/keyring-type.h>
#include <asm/uaccess.h>
#include "internal.h"
.read = keyring_read,
};
+EXPORT_SYMBOL(key_type_keyring);
+
/*
* semaphore to serialise link/link calls to prevent two link calls in parallel
* introducing a cycle
* publish the name of a keyring so that it can be found by name (if it has
* one)
*/
-void keyring_publish_name(struct key *keyring)
+static void keyring_publish_name(struct key *keyring)
{
int bucket;
* allocate a keyring and link into the destination keyring
*/
struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid,
- struct task_struct *ctx, unsigned long flags,
+ const struct cred *cred, unsigned long flags,
struct key *dest)
{
struct key *keyring;
int ret;
keyring = key_alloc(&key_type_keyring, description,
- uid, gid, ctx,
+ uid, gid, cred,
(KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_ALL,
flags);
* - we propagate the possession attribute from the keyring ref to the key ref
*/
key_ref_t keyring_search_aux(key_ref_t keyring_ref,
- struct task_struct *context,
+ const struct cred *cred,
struct key_type *type,
const void *description,
key_match_func_t match)
struct keyring_list *keylist;
struct timespec now;
- unsigned long possessed;
+ unsigned long possessed, kflags;
struct key *keyring, *key;
key_ref_t key_ref;
long err;
key_check(keyring);
/* top keyring must have search permission to begin the search */
- err = key_task_permission(keyring_ref, context, KEY_SEARCH);
+ err = key_task_permission(keyring_ref, cred, KEY_SEARCH);
if (err < 0) {
key_ref = ERR_PTR(err);
goto error;
err = -EAGAIN;
sp = 0;
+ /* firstly we should check to see if this top-level keyring is what we
+ * are looking for */
+ key_ref = ERR_PTR(-EAGAIN);
+ kflags = keyring->flags;
+ if (keyring->type == type && match(keyring, description)) {
+ key = keyring;
+
+ /* check it isn't negative and hasn't expired or been
+ * revoked */
+ if (kflags & (1 << KEY_FLAG_REVOKED))
+ goto error_2;
+ if (key->expiry && now.tv_sec >= key->expiry)
+ goto error_2;
+ key_ref = ERR_PTR(-ENOKEY);
+ if (kflags & (1 << KEY_FLAG_NEGATIVE))
+ goto error_2;
+ goto found;
+ }
+
+ /* otherwise, the top keyring must not be revoked, expired, or
+ * negatively instantiated if we are to search it */
+ key_ref = ERR_PTR(-EAGAIN);
+ if (kflags & ((1 << KEY_FLAG_REVOKED) | (1 << KEY_FLAG_NEGATIVE)) ||
+ (keyring->expiry && now.tv_sec >= keyring->expiry))
+ goto error_2;
+
/* start processing a new keyring */
descend:
if (test_bit(KEY_FLAG_REVOKED, &keyring->flags))
/* iterate through the keys in this keyring first */
for (kix = 0; kix < keylist->nkeys; kix++) {
key = keylist->keys[kix];
+ kflags = key->flags;
/* ignore keys not of this type */
if (key->type != type)
continue;
/* skip revoked keys and expired keys */
- if (test_bit(KEY_FLAG_REVOKED, &key->flags))
+ if (kflags & (1 << KEY_FLAG_REVOKED))
continue;
if (key->expiry && now.tv_sec >= key->expiry)
/* key must have search permissions */
if (key_task_permission(make_key_ref(key, possessed),
- context, KEY_SEARCH) < 0)
+ cred, KEY_SEARCH) < 0)
continue;
- /* we set a different error code if we find a negative key */
- if (test_bit(KEY_FLAG_NEGATIVE, &key->flags)) {
+ /* we set a different error code if we pass a negative key */
+ if (kflags & (1 << KEY_FLAG_NEGATIVE)) {
err = -ENOKEY;
continue;
}
continue;
if (key_task_permission(make_key_ref(key, possessed),
- context, KEY_SEARCH) < 0)
+ cred, KEY_SEARCH) < 0)
continue;
/* stack the current position */
if (!type->match)
return ERR_PTR(-ENOKEY);
- return keyring_search_aux(keyring, current,
+ return keyring_search_aux(keyring, current->cred,
type, description, type->match);
} /* end keyring_search() */
/*
* 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
+ * - normally only finds keyrings with search permission for the current process
*/
-struct key *find_keyring_by_name(const char *name, key_serial_t bound)
+struct key *find_keyring_by_name(const char *name, bool skip_perm_check)
{
struct key *keyring;
int bucket;
&keyring_name_hash[bucket],
type_data.link
) {
+ if (keyring->user->user_ns != current_user_ns())
+ continue;
+
if (test_bit(KEY_FLAG_REVOKED, &keyring->flags))
continue;
if (strcmp(keyring->description, name) != 0)
continue;
- if (key_permission(make_key_ref(keyring, 0),
+ if (!skip_perm_check &&
+ 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);
BUG_ON(size > PAGE_SIZE);
ret = -ENOMEM;
- nklist = kmalloc(size, GFP_KERNEL);
+ nklist = kmemdup(klist, size, GFP_KERNEL);
if (!nklist)
goto error2;
- memcpy(nklist, klist, size);
-
/* replace matched key */
atomic_inc(&key->usage);
nklist->keys[loop] = key;
}
} /* end keyring_revoke() */
+
+/*
+ * Determine whether a key is dead
+ */
+static bool key_is_dead(struct key *key, time_t limit)
+{
+ return test_bit(KEY_FLAG_DEAD, &key->flags) ||
+ (key->expiry > 0 && key->expiry <= limit);
+}
+
+/*
+ * Collect garbage from the contents of a keyring
+ */
+void keyring_gc(struct key *keyring, time_t limit)
+{
+ struct keyring_list *klist, *new;
+ struct key *key;
+ int loop, keep, max;
+
+ kenter("{%x,%s}", key_serial(keyring), keyring->description);
+
+ down_write(&keyring->sem);
+
+ klist = keyring->payload.subscriptions;
+ if (!klist)
+ goto no_klist;
+
+ /* work out how many subscriptions we're keeping */
+ keep = 0;
+ for (loop = klist->nkeys - 1; loop >= 0; loop--)
+ if (!key_is_dead(klist->keys[loop], limit))
+ keep++;
+
+ if (keep == klist->nkeys)
+ goto just_return;
+
+ /* allocate a new keyring payload */
+ max = roundup(keep, 4);
+ new = kmalloc(sizeof(struct keyring_list) + max * sizeof(struct key *),
+ GFP_KERNEL);
+ if (!new)
+ goto nomem;
+ new->maxkeys = max;
+ new->nkeys = 0;
+ new->delkey = 0;
+
+ /* install the live keys
+ * - must take care as expired keys may be updated back to life
+ */
+ keep = 0;
+ for (loop = klist->nkeys - 1; loop >= 0; loop--) {
+ key = klist->keys[loop];
+ if (!key_is_dead(key, limit)) {
+ if (keep >= max)
+ goto discard_new;
+ new->keys[keep++] = key_get(key);
+ }
+ }
+ new->nkeys = keep;
+
+ /* adjust the quota */
+ key_payload_reserve(keyring,
+ sizeof(struct keyring_list) +
+ KEYQUOTA_LINK_BYTES * keep);
+
+ if (keep == 0) {
+ rcu_assign_pointer(keyring->payload.subscriptions, NULL);
+ kfree(new);
+ } else {
+ rcu_assign_pointer(keyring->payload.subscriptions, new);
+ }
+
+ up_write(&keyring->sem);
+
+ call_rcu(&klist->rcu, keyring_clear_rcu_disposal);
+ kleave(" [yes]");
+ return;
+
+discard_new:
+ new->nkeys = keep;
+ keyring_clear_rcu_disposal(&new->rcu);
+ up_write(&keyring->sem);
+ kleave(" [discard]");
+ return;
+
+just_return:
+ up_write(&keyring->sem);
+ kleave(" [no dead]");
+ return;
+
+no_klist:
+ up_write(&keyring->sem);
+ kleave(" [no_klist]");
+ return;
+
+nomem:
+ up_write(&keyring->sem);
+ kleave(" [oom]");
+}
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff