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[PATCH] keys: discard the contents of a key on revocation 

Cause the keys linked to a keyring to be unlinked from it when revoked and it
causes the data attached to a user-defined key to be discarded when revoked.

This frees up most of the quota a key occupied at that point, rather than
waiting for the key to actually be destroyed.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
David Howells 2006-06-26 00:24:51 -07:00 committed by Linus Torvalds
parent 7e047ef5fe
commit 31204ed925
3 changed files with 46 additions and 1 deletions
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1
include/keys/user-type.h
View File

@ -37,6 +37,7 @@ extern struct key_type key_type_user;
extern int user_instantiate(struct key *key, const void *data, size_t datalen);
extern int user_update(struct key *key, const void *data, size_t datalen);
extern int user_match(const struct key *key, const void *criterion);
extern void user_revoke(struct key *key);
extern void user_destroy(struct key *key);
extern void user_describe(const struct key *user, struct seq_file *m);
extern long user_read(const struct key *key,

21
security/keys/keyring.c
View File

@ -49,6 +49,7 @@ static inline unsigned keyring_hash(const char *desc)
static int keyring_instantiate(struct key *keyring,
const void *data, size_t datalen);
static int keyring_match(const struct key *keyring, const void *criterion);
static void keyring_revoke(struct key *keyring);
static void keyring_destroy(struct key *keyring);
static void keyring_describe(const struct key *keyring, struct seq_file *m);
static long keyring_read(const struct key *keyring,
@ -59,6 +60,7 @@ struct key_type key_type_keyring = {
.def_datalen = sizeof(struct keyring_list),
.instantiate = keyring_instantiate,
.match = keyring_match,
.revoke = keyring_revoke,
.destroy = keyring_destroy,
.describe = keyring_describe,
.read = keyring_read,
@ -953,3 +955,22 @@ int keyring_clear(struct key *keyring)
} /* end keyring_clear() */
EXPORT_SYMBOL(keyring_clear);
/*****************************************************************************/
/*
* dispose of the links from a revoked keyring
* - called with the key sem write-locked
*/
static void keyring_revoke(struct key *keyring)
{
struct keyring_list *klist = keyring->payload.subscriptions;
/* adjust the quota */
key_payload_reserve(keyring, 0);
if (klist) {
rcu_assign_pointer(keyring->payload.subscriptions, NULL);
call_rcu(&klist->rcu, keyring_clear_rcu_disposal);
}
} /* end keyring_revoke() */

25
security/keys/user_defined.c
View File

@ -28,6 +28,7 @@ struct key_type key_type_user = {
.instantiate = user_instantiate,
.update = user_update,
.match = user_match,
.revoke = user_revoke,
.destroy = user_destroy,
.describe = user_describe,
.read = user_read,
@ -67,6 +68,7 @@ error:
return ret;
} /* end user_instantiate() */
EXPORT_SYMBOL_GPL(user_instantiate);
/*****************************************************************************/
@ -141,7 +143,28 @@ EXPORT_SYMBOL_GPL(user_match);
/*****************************************************************************/
/*
* dispose of the data dangling from the corpse of a user
* dispose of the links from a revoked keyring
* - called with the key sem write-locked
*/
void user_revoke(struct key *key)
{
struct user_key_payload *upayload = key->payload.data;
/* clear the quota */
key_payload_reserve(key, 0);
if (upayload) {
rcu_assign_pointer(key->payload.data, NULL);
call_rcu(&upayload->rcu, user_update_rcu_disposal);
}
} /* end user_revoke() */
EXPORT_SYMBOL(user_revoke);
/*****************************************************************************/
/*
* dispose of the data dangling from the corpse of a user key
*/
void user_destroy(struct key *key)
{