KEYS: Use keyring_alloc() to create special keyrings

Use keyring_alloc() to create special keyrings now that it has a permissions
parameter rather than using key_alloc() + key_instantiate_and_link().

Also document and export keyring_alloc() so that modules can use it too.

Signed-off-by: David Howells <dhowells@redhat.com>

5 files changed, 31 insertions, 24 deletions

diff --git a/Documentation/security/keys.txt b/Documentation/security/keys.txt
index aa0dbd74b71b..a4f9125c0333 100644
--- a/Documentation/security/keys.txt
+++ b/Documentation/security/keys.txt
@@ -990,6 +990,23 @@ payload contents" for more information.
     reference pointer if successful.
 
 
+(*) A keyring can be created by:
+
+        struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid,
+                                  const struct cred *cred,
+                                  key_perm_t perm,
+                                  unsigned long flags,
+                                  struct key *dest);
+
+    This creates a keyring with the given attributes and returns it.  If dest
+    is not NULL, the new keyring will be linked into the keyring to which it
+    points.  No permission checks are made upon the destination keyring.
+
+    Error EDQUOT can be returned if the keyring would overload the quota (pass
+    KEY_ALLOC_NOT_IN_QUOTA in flags if the keyring shouldn't be accounted
+    towards the user's quota).  Error ENOMEM can also be returned.
+
+
 (*) To check the validity of a key, this function can be called:
 
         int validate_key(struct key *key);
diff --git a/fs/cifs/cifsacl.c b/fs/cifs/cifsacl.c
index 05f4dc263a23..a8a753c8fcd5 100644
--- a/fs/cifs/cifsacl.c
+++ b/fs/cifs/cifsacl.c
@@ -537,19 +537,15 @@ init_cifs_idmap(void)
         if (!cred)
                 return -ENOMEM;
 
-        keyring = key_alloc(&key_type_keyring, ".cifs_idmap", 0, 0, cred,
-                            (KEY_POS_ALL & ~KEY_POS_SETATTR) |
-                            KEY_USR_VIEW | KEY_USR_READ,
-                            KEY_ALLOC_NOT_IN_QUOTA);
+        keyring = keyring_alloc(".cifs_idmap", 0, 0, cred,
+                                (KEY_POS_ALL & ~KEY_POS_SETATTR) |
+                                KEY_USR_VIEW | KEY_USR_READ,
+                                KEY_ALLOC_NOT_IN_QUOTA, NULL);
         if (IS_ERR(keyring)) {
                 ret = PTR_ERR(keyring);
                 goto failed_put_cred;
         }
 
-        ret = key_instantiate_and_link(keyring, NULL, 0, NULL, NULL);
-        if (ret < 0)
-                goto failed_put_key;
-
         ret = register_key_type(&cifs_idmap_key_type);
         if (ret < 0)
                 goto failed_put_key;
diff --git a/fs/nfs/idmap.c b/fs/nfs/idmap.c
index a850079467d8..957134b4c0fd 100644
--- a/fs/nfs/idmap.c
+++ b/fs/nfs/idmap.c
@@ -192,19 +192,15 @@ static int nfs_idmap_init_keyring(void)
         if (!cred)
                 return -ENOMEM;
 
-        keyring = key_alloc(&key_type_keyring, ".id_resolver", 0, 0, cred,
-                             (KEY_POS_ALL & ~KEY_POS_SETATTR) |
-                             KEY_USR_VIEW | KEY_USR_READ,
-                             KEY_ALLOC_NOT_IN_QUOTA);
+        keyring = keyring_alloc(".id_resolver", 0, 0, cred,
+                                (KEY_POS_ALL & ~KEY_POS_SETATTR) |
+                                KEY_USR_VIEW | KEY_USR_READ,
+                                KEY_ALLOC_NOT_IN_QUOTA, NULL);
         if (IS_ERR(keyring)) {
                 ret = PTR_ERR(keyring);
                 goto failed_put_cred;
         }
 
-        ret = key_instantiate_and_link(keyring, NULL, 0, NULL, NULL);
-        if (ret < 0)
-                goto failed_put_key;
-
         ret = register_key_type(&key_type_id_resolver);
         if (ret < 0)
                 goto failed_put_key;
diff --git a/net/dns_resolver/dns_key.c b/net/dns_resolver/dns_key.c
index d9507dd05818..f2c379d835e3 100644
--- a/net/dns_resolver/dns_key.c
+++ b/net/dns_resolver/dns_key.c
@@ -259,19 +259,15 @@ static int __init init_dns_resolver(void)
         if (!cred)
                 return -ENOMEM;
 
-        keyring = key_alloc(&key_type_keyring, ".dns_resolver", 0, 0, cred,
-                            (KEY_POS_ALL & ~KEY_POS_SETATTR) |
-                            KEY_USR_VIEW | KEY_USR_READ,
-                            KEY_ALLOC_NOT_IN_QUOTA);
+        keyring = keyring_alloc(".dns_resolver", 0, 0, cred,
+                                (KEY_POS_ALL & ~KEY_POS_SETATTR) |
+                                KEY_USR_VIEW | KEY_USR_READ,
+                                KEY_ALLOC_NOT_IN_QUOTA, NULL);
         if (IS_ERR(keyring)) {
                 ret = PTR_ERR(keyring);
                 goto failed_put_cred;
         }
 
-        ret = key_instantiate_and_link(keyring, NULL, 0, NULL, NULL);
-        if (ret < 0)
-                goto failed_put_key;
-
         ret = register_key_type(&key_type_dns_resolver);
         if (ret < 0)
                 goto failed_put_key;
@@ -303,3 +299,4 @@ static void __exit exit_dns_resolver(void)
 module_init(init_dns_resolver)
 module_exit(exit_dns_resolver)
 MODULE_LICENSE("GPL");
+
diff --git a/security/keys/keyring.c b/security/keys/keyring.c
index cf704a92083f..8c25558da14e 100644
--- a/security/keys/keyring.c
+++ b/security/keys/keyring.c
@@ -275,6 +275,7 @@ struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid,
 
         return keyring;
 }
+EXPORT_SYMBOL(keyring_alloc);
 
 /**
  * keyring_search_aux - Search a keyring tree for a key matching some criteria