This file and its associated key-type specific variants are used by the
/sbin/request-key program to determine which program it should run to
instantiate a key.
request-key looks first in /etc/request-key.d/ for a file of the key type name
plus ".conf" that it can use. If that is not found, it will fall back to
request-key works scans through the chosen file one line at a time until it
finds a match, which it will then use. If it doesnt find a match, itll return
an error and the kernel will automatically negate the key.
Any blank line or line beginning with a hash mark # is considered to be a
comment and ignored.
All other lines are assumed to be command lines with a number of white space
<op> <type> <description> <callout-info> <prog> <arg1> <arg2> ...
The first four fields are used to match the parameters passed to request-key by
the kernel. op is the operation type; currently the only supported
operation is "create".
type, description and callout-info match the three parameters
passed to keyctl request2 or the request_key() system call. Each of
these may contain one or more asterisk * characters as wildcards anywhere
within the string.
Should a match be made, the program specified by <prog> will be execd. This
must have a fully qualified path name. argv will be set from the part of the
program name that follows the last slash / character.
If the program name is prefixed with a pipe bar character |, then the program
will be forked and execd attached to three pipes. The callout information will
be piped to it on its stdin and the intended payload data will be retrieved
from its stdout. Anything sent to stderr will be posted in syslog. If the
program exits 0, then /sbin/request-key will attempt to instantiate the key
with the data read from stdout. If it fails in any other way, then request-key
will attempt to execute the appropriate negate operation command.
The program arguments can be substituted with various macros. Only complete
argument substitution is supported - macro substitutions cant be embedded. All
macros begin with a percent character %. An argument beginning with two
percent characters will have one of them discarded.
The following macros are supported:
%o Operation type
%k Key ID
%t Key type
%d Key description
%c Callout information
%u Key UID
%g Key GID
%T Requestors thread keyring
%P Requestors process keyring
%S Requestors session keyring
Theres another macro substitution too that permits the interpolation of the
contents of a key:
This performs a lookup for a key of the given type and description on the
requestors keyrings, and if found, substitutes the contents for the macro. If
not found an error will be logged and the key under construction will be
A basic file will be installed in the /etc. This will contain two debugging
lines that can be used to test the installation:
create user debug:* negate /bin/keyctl negate %k 30 %S
create user debug:loop:* * |/bin/cat
create user debug:* * /usr/share/keyutils/request-key-debug.sh %k %d %c %S
negate * * * /bin/keyctl negate %k 30 %S
This is set up so that something like:
keyctl request2 user debug:xxxx negate
will create a negative user-defined key, something like:
keyctl request2 user debug:yyyy spoon
will create an instantiated user-defined key with "Debug spoon" as the payload,
and something like:
keyctl request2 user debug:loop:zzzz abcdefghijkl
will create an instantiated user-defined key with the callout information as