[AF_RXRPC]: Key facility changes for AF_RXRPC

Export the keyring key type definition and document its availability.

Add alternative types into the key's type_data union to make it more useful.
Not all users necessarily want to use it as a list_head (AF_RXRPC doesn't, for
example), so make it clear that it can be used in other ways.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 16 insertions, 0 deletions

diff --git a/Documentation/keys.txt b/Documentation/keys.txt
index 60c665d9cfaa..81d9aa097298 100644
--- a/Documentation/keys.txt
+++ b/Documentation/keys.txt
@@ -859,6 +859,18 @@ payload contents" for more information.
         void unregister_key_type(struct key_type *type);
 
 
+Under some circumstances, it may be desirable to desirable to deal with a
+bundle of keys.  The facility provides access to the keyring type for managing
+such a bundle:
+
+        struct key_type key_type_keyring;
+
+This can be used with a function such as request_key() to find a specific
+keyring in a process's keyrings.  A keyring thus found can then be searched
+with keyring_search().  Note that it is not possible to use request_key() to
+search a specific keyring, so using keyrings in this way is of limited utility.
+
+
 ===================================
 NOTES ON ACCESSING PAYLOAD CONTENTS
 ===================================
diff --git a/include/linux/key.h b/include/linux/key.h
index 169f05e4863e..a9220e75782e 100644
--- a/include/linux/key.h
+++ b/include/linux/key.h
@@ -160,6 +160,8 @@ struct key {
          */
         union {
                 struct list_head        link;
+                unsigned long           x[2];
+                void                    *p[2];
         } type_data;
 
         /* key data
diff --git a/security/keys/keyring.c b/security/keys/keyring.c
index ad45ce73964b..88292e3dee96 100644
--- a/security/keys/keyring.c
+++ b/security/keys/keyring.c
@@ -66,6 +66,8 @@ struct key_type key_type_keyring = {
         .read           = keyring_read,
 };
 
+EXPORT_SYMBOL(key_type_keyring);
+
 /*
  * semaphore to serialise link/link calls to prevent two link calls in parallel
  * introducing a cycle