aboutsummaryrefslogtreecommitdiff
path: root/security
diff options
context:
space:
mode:
authorJames Morris <jmorris@namei.org>2010-05-06 22:21:04 +1000
committerJames Morris <jmorris@namei.org>2010-05-06 22:21:04 +1000
commit043b4d40f53131c5f72eca2a46555fe35328a930 (patch)
tree02a40eeb688f7ed9730e26a22f39ad7e04378de2 /security
parent292823814261e085cdcef06b6b691e6c2563fbd4 (diff)
parent722154e4cacf015161efe60009ae9be23d492296 (diff)
downloadlinux-2.6.34-ux500-043b4d40f53131c5f72eca2a46555fe35328a930.tar.gz
Merge branch 'master' into next
Conflicts: security/keys/keyring.c Resolved conflict with whitespace fix in find_keyring_by_name() Signed-off-by: James Morris <jmorris@namei.org>
Diffstat (limited to 'security')
-rw-r--r--security/keys/keyring.c41
-rw-r--r--security/keys/request_key.c2
2 files changed, 23 insertions, 20 deletions
diff --git a/security/keys/keyring.c b/security/keys/keyring.c
index 29de5ee3457..3f425a65906 100644
--- a/security/keys/keyring.c
+++ b/security/keys/keyring.c
@@ -20,6 +20,11 @@
#include <linux/uaccess.h>
#include "internal.h"
+#define rcu_dereference_locked_keyring(keyring) \
+ (rcu_dereference_protected( \
+ (keyring)->payload.subscriptions, \
+ rwsem_is_locked((struct rw_semaphore *)&(keyring)->sem)))
+
/*
* when plumbing the depths of the key tree, this sets a hard limit set on how
* deep we're willing to go
@@ -199,8 +204,7 @@ static long keyring_read(const struct key *keyring,
int loop, ret;
ret = 0;
- klist = keyring->payload.subscriptions;
-
+ klist = rcu_dereference_locked_keyring(keyring);
if (klist) {
/* calculate how much data we could return */
qty = klist->nkeys * sizeof(key_serial_t);
@@ -524,9 +528,8 @@ struct key *find_keyring_by_name(const char *name, bool skip_perm_check)
struct key *keyring;
int bucket;
- keyring = ERR_PTR(-EINVAL);
if (!name)
- goto error;
+ return ERR_PTR(-EINVAL);
bucket = keyring_hash(name);
@@ -553,17 +556,18 @@ struct key *find_keyring_by_name(const char *name, bool skip_perm_check)
KEY_SEARCH) < 0)
continue;
- /* we've got a match */
- atomic_inc(&keyring->usage);
- read_unlock(&keyring_name_lock);
- goto error;
+ /* we've got a match but we might end up racing with
+ * key_cleanup() if the keyring is currently 'dead'
+ * (ie. it has a zero usage count) */
+ if (!atomic_inc_not_zero(&keyring->usage))
+ continue;
+ goto out;
}
}
- read_unlock(&keyring_name_lock);
keyring = ERR_PTR(-ENOKEY);
-
-error:
+out:
+ read_unlock(&keyring_name_lock);
return keyring;
} /* end find_keyring_by_name() */
@@ -719,8 +723,7 @@ int __key_link(struct key *keyring, struct key *key)
}
/* see if there's a matching key we can displace */
- klist = keyring->payload.subscriptions;
-
+ klist = rcu_dereference_locked_keyring(keyring);
if (klist && klist->nkeys > 0) {
struct key_type *type = key->type;
@@ -764,8 +767,6 @@ int __key_link(struct key *keyring, struct key *key)
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);
@@ -867,7 +868,7 @@ int key_unlink(struct key *keyring, struct key *key)
down_write(&keyring->sem);
- klist = keyring->payload.subscriptions;
+ klist = rcu_dereference_locked_keyring(keyring);
if (klist) {
/* search the keyring for the key */
for (loop = 0; loop < klist->nkeys; loop++)
@@ -958,7 +959,7 @@ int keyring_clear(struct key *keyring)
/* detach the pointer block with the locks held */
down_write(&keyring->sem);
- klist = keyring->payload.subscriptions;
+ klist = rcu_dereference_locked_keyring(keyring);
if (klist) {
/* adjust the quota */
key_payload_reserve(keyring,
@@ -990,7 +991,9 @@ EXPORT_SYMBOL(keyring_clear);
*/
static void keyring_revoke(struct key *keyring)
{
- struct keyring_list *klist = keyring->payload.subscriptions;
+ struct keyring_list *klist;
+
+ klist = rcu_dereference_locked_keyring(keyring);
/* adjust the quota */
key_payload_reserve(keyring, 0);
@@ -1024,7 +1027,7 @@ void keyring_gc(struct key *keyring, time_t limit)
down_write(&keyring->sem);
- klist = keyring->payload.subscriptions;
+ klist = rcu_dereference_locked_keyring(keyring);
if (!klist)
goto no_klist;
diff --git a/security/keys/request_key.c b/security/keys/request_key.c
index 1bc38587adc..ac49c8aacbf 100644
--- a/security/keys/request_key.c
+++ b/security/keys/request_key.c
@@ -94,7 +94,7 @@ static int call_sbin_request_key(struct key_construction *cons,
}
/* attach the auth key to the session keyring */
- ret = __key_link(keyring, authkey);
+ ret = key_link(keyring, authkey);
if (ret < 0)
goto error_link;