summaryrefslogtreecommitdiffstats
path: root/security/keys
diff options
context:
space:
mode:
Diffstat (limited to 'security/keys')
-rw-r--r--security/keys/gc.c9
-rw-r--r--security/keys/keyring.c41
-rw-r--r--security/keys/request_key.c24
-rw-r--r--security/keys/user_defined.c3
4 files changed, 47 insertions, 30 deletions
diff --git a/security/keys/gc.c b/security/keys/gc.c
index 1990231..a46e825 100644
--- a/security/keys/gc.c
+++ b/security/keys/gc.c
@@ -77,10 +77,10 @@ static bool key_gc_keyring(struct key *keyring, time_t limit)
goto dont_gc;
/* scan the keyring looking for dead keys */
- klist = rcu_dereference_check(keyring->payload.subscriptions,
- lockdep_is_held(&key_serial_lock));
+ rcu_read_lock();
+ klist = rcu_dereference(keyring->payload.subscriptions);
if (!klist)
- goto dont_gc;
+ goto unlock_dont_gc;
for (loop = klist->nkeys - 1; loop >= 0; loop--) {
key = klist->keys[loop];
@@ -89,11 +89,14 @@ static bool key_gc_keyring(struct key *keyring, time_t limit)
goto do_gc;
}
+unlock_dont_gc:
+ rcu_read_unlock();
dont_gc:
kleave(" = false");
return false;
do_gc:
+ rcu_read_unlock();
key_gc_cursor = keyring->serial;
key_get(keyring);
spin_unlock(&key_serial_lock);
diff --git a/security/keys/keyring.c b/security/keys/keyring.c
index e814d21..1e4b003 100644
--- a/security/keys/keyring.c
+++ b/security/keys/keyring.c
@@ -20,6 +20,11 @@
#include <asm/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
@@ -201,8 +206,7 @@ static long keyring_read(const struct key *keyring,
int loop, ret;
ret = 0;
- klist = rcu_dereference(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);
@@ -526,9 +530,8 @@ 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);
@@ -555,17 +558,18 @@ 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() */
@@ -720,8 +724,7 @@ 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;
@@ -765,8 +768,6 @@ 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);
@@ -868,7 +869,7 @@ 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++)
@@ -959,7 +960,7 @@ 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,
@@ -991,7 +992,9 @@ 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);
@@ -1025,7 +1028,7 @@ 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 03fe63e..d8c1a6a 100644
--- a/security/keys/request_key.c
+++ b/security/keys/request_key.c
@@ -68,7 +68,8 @@ static int call_sbin_request_key(struct key_construction *cons,
{
const struct cred *cred = current_cred();
key_serial_t prkey, sskey;
- struct key *key = cons->key, *authkey = cons->authkey, *keyring;
+ struct key *key = cons->key, *authkey = cons->authkey, *keyring,
+ *session;
char *argv[9], *envp[3], uid_str[12], gid_str[12];
char key_str[12], keyring_str[3][12];
char desc[20];
@@ -93,7 +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;
@@ -112,10 +113,12 @@ static int call_sbin_request_key(struct key_construction *cons,
if (cred->tgcred->process_keyring)
prkey = cred->tgcred->process_keyring->serial;
- if (cred->tgcred->session_keyring)
- sskey = rcu_dereference(cred->tgcred->session_keyring)->serial;
- else
- sskey = cred->user->session_keyring->serial;
+ rcu_read_lock();
+ session = rcu_dereference(cred->tgcred->session_keyring);
+ if (!session)
+ session = cred->user->session_keyring;
+ sskey = session->serial;
+ rcu_read_unlock();
sprintf(keyring_str[2], "%d", sskey);
@@ -336,8 +339,10 @@ static int construct_alloc_key(struct key_type *type,
key_already_present:
mutex_unlock(&key_construction_mutex);
- if (dest_keyring)
+ if (dest_keyring) {
+ __key_link(dest_keyring, key_ref_to_ptr(key_ref));
up_write(&dest_keyring->sem);
+ }
mutex_unlock(&user->cons_lock);
key_put(key);
*_key = key = key_ref_to_ptr(key_ref);
@@ -428,6 +433,11 @@ struct key *request_key_and_link(struct key_type *type,
if (!IS_ERR(key_ref)) {
key = key_ref_to_ptr(key_ref);
+ if (dest_keyring) {
+ construct_get_dest_keyring(&dest_keyring);
+ key_link(dest_keyring, key);
+ key_put(dest_keyring);
+ }
} else if (PTR_ERR(key_ref) != -EAGAIN) {
key = ERR_CAST(key_ref);
} else {
diff --git a/security/keys/user_defined.c b/security/keys/user_defined.c
index 7c687d5..e9aa079 100644
--- a/security/keys/user_defined.c
+++ b/security/keys/user_defined.c
@@ -199,7 +199,8 @@ long user_read(const struct key *key, char __user *buffer, size_t buflen)
struct user_key_payload *upayload;
long ret;
- upayload = rcu_dereference(key->payload.data);
+ upayload = rcu_dereference_protected(
+ key->payload.data, rwsem_is_locked(&((struct key *)key)->sem));
ret = upayload->datalen;
/* we can return the data as is */
OpenPOWER on IntegriCloud