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-rw-r--r--security/keys/permission.c29
1 files changed, 17 insertions, 12 deletions
diff --git a/security/keys/permission.c b/security/keys/permission.c
index 3b41f9b5253..5d9fc7b93f2 100644
--- a/security/keys/permission.c
+++ b/security/keys/permission.c
@@ -14,12 +14,19 @@
#include "internal.h"
/*****************************************************************************/
-/*
- * check to see whether permission is granted to use a key in the desired way,
- * but permit the security modules to override
+/**
+ * key_task_permission - Check a key can be used
+ * @key_ref: The key to check
+ * @cred: The credentials to use
+ * @perm: The permissions to check for
+ *
+ * Check to see whether permission is granted to use a key in the desired way,
+ * but permit the security modules to override.
+ *
+ * The caller must hold either a ref on cred or must hold the RCU readlock or a
+ * spinlock.
*/
-int key_task_permission(const key_ref_t key_ref,
- struct task_struct *context,
+int key_task_permission(const key_ref_t key_ref, const struct cred *cred,
key_perm_t perm)
{
struct key *key;
@@ -29,7 +36,7 @@ int key_task_permission(const key_ref_t key_ref,
key = key_ref_to_ptr(key_ref);
/* use the second 8-bits of permissions for keys the caller owns */
- if (key->uid == context->fsuid) {
+ if (key->uid == cred->fsuid) {
kperm = key->perm >> 16;
goto use_these_perms;
}
@@ -37,15 +44,12 @@ int key_task_permission(const key_ref_t key_ref,
/* use the third 8-bits of permissions for keys the caller has a group
* membership in common with */
if (key->gid != -1 && key->perm & KEY_GRP_ALL) {
- if (key->gid == context->fsgid) {
+ if (key->gid == cred->fsgid) {
kperm = key->perm >> 8;
goto use_these_perms;
}
- task_lock(context);
- ret = groups_search(context->group_info, key->gid);
- task_unlock(context);
-
+ ret = groups_search(cred->group_info, key->gid);
if (ret) {
kperm = key->perm >> 8;
goto use_these_perms;
@@ -56,6 +60,7 @@ int key_task_permission(const key_ref_t key_ref,
kperm = key->perm;
use_these_perms:
+
/* use the top 8-bits of permissions for keys the caller possesses
* - possessor permissions are additive with other permissions
*/
@@ -68,7 +73,7 @@ use_these_perms:
return -EACCES;
/* let LSM be the final arbiter */
- return security_key_permission(key_ref, context, perm);
+ return security_key_permission(key_ref, cred, perm);
} /* end key_task_permission() */