1 files changed, 30 insertions, 1 deletions
diff --git a/Documentation/security/keys.txt b/Documentation/security/keys.txt
index 787717091421..aa0dbd74b71b 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.
 
@@ -793,6 +805,23 @@ The keyctl syscall functions are:
      kernel and resumes executing userspace.
 
 
+ (*) Invalidate a key.
+
+	long keyctl(KEYCTL_INVALIDATE, key_serial_t key);
+
+     This function marks a key as being invalidated and then wakes up the
+     garbage collector.  The garbage collector immediately removes invalidated
+     keys from all keyrings and deletes the key when its reference count
+     reaches zero.
+
+     Keys that are marked invalidated become invisible to normal key operations
+     immediately, though they are still visible in /proc/keys until deleted
+     (they're marked with an 'i' flag).
+
+     A process must have search permission on the key for this function to be
+     successful.
+
+
 ===============
 KERNEL SERVICES
 ===============