Documentation/security/keys-request-key.txt

9 The process starts by either the kernel requesting a service by calling
56 The two async in-kernel calls may return keys that are still in the process of
60 The userspace interface links the key to a keyring associated with the process
71 THE PROCESS
76  (1) Process A calls request_key() [the userspace syscall calls the kernel
79  (2) request_key() searches the process's subscribed keyrings to see if there's
81      and callout_info is not set, an error is returned.  Otherwise the process
89      (b) An authorisation key V that refers to key U and notes that process A
105      This will permit it to then search the keyrings of process A with the
106      UID, GID, groups and security info of process A as if it was process A,
122 context specified by auth key X will still be process A, as it was in auth key
125 This is because process A's keyrings can't simply be attached to
143 Should the /sbin/request-key process exit anything other than 0 or die on a
169 The process stops immediately a valid key is found with permission granted to
176  (1) If extant, the process's thread keyring is searched.
178  (2) If extant, the process's process keyring is searched.
180  (3) The process's session keyring is searched.
182  (4) If the process has assumed the authority associated with a request_key()
185      (a) If extant, the calling process's thread keyring is searched.
187      (b) If extant, the calling process's process keyring is searched.
189      (c) The calling process's session keyring is searched.