[PATCH] keys: update the documentation with info about "logon" keys

[Jeff Layton <jlayton@redhat.com>]

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
---
 Documentation/security/keys.txt |   14 +++++++++++++-
 1 files changed, 13 insertions(+), 1 deletions(-)

diff --git a/Documentation/security/keys.txt b/Documentation/security/keys.txt
index 7877170..1f5517a 100644
--- a/Documentation/security/keys.txt
+++ b/Documentation/security/keys.txt
@@ -123,7 +123,7 @@ KEY SERVICE OVERVIEW
 
 The key service provides a number of features besides keys:
 
- (*) The key service defines two special key types:
+ (*) The key service defines three special key types:
 
      (+) "keyring"
 
@@ -137,6 +137,18 @@ The key service provides a number of features besides keys:
 	 blobs of data. These can be created, updated and read by userspace,
 	 and aren't intended for use by kernel services.
 
+     (+) "logon"
+
+         Like a "user" key, a "logon" key has a payload that is an arbitrary
+         blob of data. It is intended as a place to store secrets which are
+	 accessible to the kernel but not to userspace programs.
+
+         The description can be arbitrary, but must be prefixed with a non-zero
+         length string that describes the key "subclass". The subclass is
+         separated from the rest of the description by a ':'. "logon" keys can
+         be created and updated from userspace, but the payload is only
+         readable from kernel space.
+
  (*) Each process subscribes to three keyrings: a thread-specific keyring, a
      process-specific keyring, and a session-specific keyring.
 
-- 
1.7.7.6