2 files changed, 36 insertions, 10 deletions

diff --git a/Documentation/keys-request-key.txt b/Documentation/keys-request-key.txt
index 5f2b9c5edbb5..22488d791168 100644
--- a/Documentation/keys-request-key.txt
+++ b/Documentation/keys-request-key.txt
@@ -56,10 +56,12 @@ A request proceeds in the following manner:
  (4) request_key() then forks and executes /sbin/request-key with a new session
      keyring that contains a link to auth key V.
 
- (5) /sbin/request-key execs an appropriate program to perform the actual
+ (5) /sbin/request-key assumes the authority associated with key U.
+
+ (6) /sbin/request-key execs an appropriate program to perform the actual
      instantiation.
 
- (6) The program may want to access another key from A's context (say a
+ (7) The program may want to access another key from A's context (say a
      Kerberos TGT key). It just requests the appropriate key, and the keyring
      search notes that the session keyring has auth key V in its bottom level.
 
@@ -67,19 +69,19 @@ A request proceeds in the following manner:
      UID, GID, groups and security info of process A as if it was process A,
      and come up with key W.
 
- (7) The program then does what it must to get the data with which to
+ (8) The program then does what it must to get the data with which to
      instantiate key U, using key W as a reference (perhaps it contacts a
      Kerberos server using the TGT) and then instantiates key U.
 
- (8) Upon instantiating key U, auth key V is automatically revoked so that it
+ (9) Upon instantiating key U, auth key V is automatically revoked so that it
      may not be used again.
 
- (9) The program then exits 0 and request_key() deletes key V and returns key
+(10) The program then exits 0 and request_key() deletes key V and returns key
      U to the caller.
 
-This also extends further. If key W (step 5 above) didn't exist, key W would be
-created uninstantiated, another auth key (X) would be created [as per step 3]
-and another copy of /sbin/request-key spawned [as per step 4]; but the context
+This also extends further. If key W (step 7 above) didn't exist, key W would be
+created uninstantiated, another auth key (X) would be created (as per step 3)
+and another copy of /sbin/request-key spawned (as per step 4); but the context
 specified by auth key X will still be process A, as it was in auth key V.
 
 This is because process A's keyrings can't simply be attached to
@@ -138,8 +140,8 @@ until one succeeds:
 
  (3) The process's session keyring is searched.
 
- (4) If the process has a request_key() authorisation key in its session
-     keyring then:
+ (4) If the process has assumed the authority associated with a request_key()
+     authorisation key then:
 
      (a) If extant, the calling process's thread keyring is searched.
 
diff --git a/Documentation/keys.txt b/Documentation/keys.txt
index eeda00f82d2c..aaa01b0e3ee9 100644
--- a/Documentation/keys.txt
+++ b/Documentation/keys.txt
@@ -308,6 +308,8 @@ process making the call:
         KEY_SPEC_USER_KEYRING           -4      UID-specific keyring
         KEY_SPEC_USER_SESSION_KEYRING   -5      UID-session keyring
         KEY_SPEC_GROUP_KEYRING          -6      GID-specific keyring
+        KEY_SPEC_REQKEY_AUTH_KEY        -7      assumed request_key()
+                                                  authorisation key
 
 
 The main syscalls are:
@@ -645,6 +647,28 @@ The keyctl syscall functions are:
      or expired keys.
 
 
+ (*) Assume the authority granted to instantiate a key
+
+        long keyctl(KEYCTL_ASSUME_AUTHORITY, key_serial_t key);
+
+     This assumes or divests the authority required to instantiate the
+     specified key. Authority can only be assumed if the thread has the
+     authorisation key associated with the specified key in its keyrings
+     somewhere.
+
+     Once authority is assumed, searches for keys will also search the
+     requester's keyrings using the requester's security label, UID, GID and
+     groups.
+
+     If the requested authority is unavailable, error EPERM will be returned,
+     likewise if the authority has been revoked because the target key is
+     already instantiated.
+
+     If the specified key is 0, then any assumed authority will be divested.
+
+     The assumed authorititive key is inherited across fork and exec.
+
+
 ===============
 KERNEL SERVICES
 ===============