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authorDavid Howells <dhowells@redhat.com>2012-01-17 20:39:40 +0000
committerJames Morris <jmorris@namei.org>2012-01-18 10:41:27 +1100
commitefde8b6e16f11e7d1681c68d86c7fd51053cada7 (patch)
tree4fb5e80428c4f36c5da35ff3319cd71c1771451c /security
parent25add8cf99c9ec8b8dc0acd8b9241e963fc0d29c (diff)
downloadlinaro-lsk-efde8b6e16f11e7d1681c68d86c7fd51053cada7.tar.gz
KEYS: Add missing smp_rmb() primitives to the keyring search code
Add missing smp_rmb() primitives to the keyring search code. When keyring payloads are appended to without replacement (thus using up spare slots in the key pointer array), an smp_wmb() is issued between the pointer assignment and the increment of the key count (nkeys). There should be corresponding read barriers between the read of nkeys and dereferences of keys[n] when n is dependent on the value of nkeys. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: James Morris <jmorris@namei.org>
Diffstat (limited to 'security')
-rw-r--r--security/keys/gc.c4
-rw-r--r--security/keys/keyring.c22
2 files changed, 18 insertions, 8 deletions
diff --git a/security/keys/gc.c b/security/keys/gc.c
index bf4d8da5a79..a42b45531aa 100644
--- a/security/keys/gc.c
+++ b/security/keys/gc.c
@@ -145,7 +145,9 @@ static void key_gc_keyring(struct key *keyring, time_t limit)
if (!klist)
goto unlock_dont_gc;
- for (loop = klist->nkeys - 1; loop >= 0; loop--) {
+ loop = klist->nkeys;
+ smp_rmb();
+ for (loop--; loop >= 0; loop--) {
key = klist->keys[loop];
if (test_bit(KEY_FLAG_DEAD, &key->flags) ||
(key->expiry > 0 && key->expiry <= limit))
diff --git a/security/keys/keyring.c b/security/keys/keyring.c
index 37a7f3b2885..d605f75292e 100644
--- a/security/keys/keyring.c
+++ b/security/keys/keyring.c
@@ -319,7 +319,7 @@ key_ref_t keyring_search_aux(key_ref_t keyring_ref,
struct key *keyring, *key;
key_ref_t key_ref;
long err;
- int sp, kix;
+ int sp, nkeys, kix;
keyring = key_ref_to_ptr(keyring_ref);
possessed = is_key_possessed(keyring_ref);
@@ -380,7 +380,9 @@ descend:
goto not_this_keyring;
/* iterate through the keys in this keyring first */
- for (kix = 0; kix < keylist->nkeys; kix++) {
+ nkeys = keylist->nkeys;
+ smp_rmb();
+ for (kix = 0; kix < nkeys; kix++) {
key = keylist->keys[kix];
kflags = key->flags;
@@ -421,7 +423,9 @@ descend:
/* search through the keyrings nested in this one */
kix = 0;
ascend:
- for (; kix < keylist->nkeys; kix++) {
+ nkeys = keylist->nkeys;
+ smp_rmb();
+ for (; kix < nkeys; kix++) {
key = keylist->keys[kix];
if (key->type != &key_type_keyring)
continue;
@@ -515,7 +519,7 @@ key_ref_t __keyring_search_one(key_ref_t keyring_ref,
struct keyring_list *klist;
unsigned long possessed;
struct key *keyring, *key;
- int loop;
+ int nkeys, loop;
keyring = key_ref_to_ptr(keyring_ref);
possessed = is_key_possessed(keyring_ref);
@@ -524,7 +528,9 @@ key_ref_t __keyring_search_one(key_ref_t keyring_ref,
klist = rcu_dereference(keyring->payload.subscriptions);
if (klist) {
- for (loop = 0; loop < klist->nkeys; loop++) {
+ nkeys = klist->nkeys;
+ smp_rmb();
+ for (loop = 0; loop < nkeys ; loop++) {
key = klist->keys[loop];
if (key->type == ktype &&
@@ -622,7 +628,7 @@ static int keyring_detect_cycle(struct key *A, struct key *B)
struct keyring_list *keylist;
struct key *subtree, *key;
- int sp, kix, ret;
+ int sp, nkeys, kix, ret;
rcu_read_lock();
@@ -645,7 +651,9 @@ descend:
ascend:
/* iterate through the remaining keys in this keyring */
- for (; kix < keylist->nkeys; kix++) {
+ nkeys = keylist->nkeys;
+ smp_rmb();
+ for (; kix < nkeys; kix++) {
key = keylist->keys[kix];
if (key == A)