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linux-next/include/uapi/linux/keyctl.h
David Howells f36f8c75ae KEYS: Add per-user_namespace registers for persistent per-UID kerberos caches
Add support for per-user_namespace registers of persistent per-UID kerberos
caches held within the kernel.

This allows the kerberos cache to be retained beyond the life of all a user's
processes so that the user's cron jobs can work.

The kerberos cache is envisioned as a keyring/key tree looking something like:

	struct user_namespace
	  \___ .krb_cache keyring		- The register
		\___ _krb.0 keyring		- Root's Kerberos cache
		\___ _krb.5000 keyring		- User 5000's Kerberos cache
		\___ _krb.5001 keyring		- User 5001's Kerberos cache
			\___ tkt785 big_key	- A ccache blob
			\___ tkt12345 big_key	- Another ccache blob

Or possibly:

	struct user_namespace
	  \___ .krb_cache keyring		- The register
		\___ _krb.0 keyring		- Root's Kerberos cache
		\___ _krb.5000 keyring		- User 5000's Kerberos cache
		\___ _krb.5001 keyring		- User 5001's Kerberos cache
			\___ tkt785 keyring	- A ccache
				\___ krbtgt/REDHAT.COM@REDHAT.COM big_key
				\___ http/REDHAT.COM@REDHAT.COM user
				\___ afs/REDHAT.COM@REDHAT.COM user
				\___ nfs/REDHAT.COM@REDHAT.COM user
				\___ krbtgt/KERNEL.ORG@KERNEL.ORG big_key
				\___ http/KERNEL.ORG@KERNEL.ORG big_key

What goes into a particular Kerberos cache is entirely up to userspace.  Kernel
support is limited to giving you the Kerberos cache keyring that you want.

The user asks for their Kerberos cache by:

	krb_cache = keyctl_get_krbcache(uid, dest_keyring);

The uid is -1 or the user's own UID for the user's own cache or the uid of some
other user's cache (requires CAP_SETUID).  This permits rpc.gssd or whatever to
mess with the cache.

The cache returned is a keyring named "_krb.<uid>" that the possessor can read,
search, clear, invalidate, unlink from and add links to.  Active LSMs get a
chance to rule on whether the caller is permitted to make a link.

Each uid's cache keyring is created when it first accessed and is given a
timeout that is extended each time this function is called so that the keyring
goes away after a while.  The timeout is configurable by sysctl but defaults to
three days.

Each user_namespace struct gets a lazily-created keyring that serves as the
register.  The cache keyrings are added to it.  This means that standard key
search and garbage collection facilities are available.

The user_namespace struct's register goes away when it does and anything left
in it is then automatically gc'd.

Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Simo Sorce <simo@redhat.com>
cc: Serge E. Hallyn <serge.hallyn@ubuntu.com>
cc: Eric W. Biederman <ebiederm@xmission.com>
2013-09-24 10:35:19 +01:00

62 lines
3.0 KiB
C

/* keyctl.h: keyctl command IDs
*
* Copyright (C) 2004, 2008 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#ifndef _LINUX_KEYCTL_H
#define _LINUX_KEYCTL_H
/* special process keyring shortcut IDs */
#define KEY_SPEC_THREAD_KEYRING -1 /* - key ID for thread-specific keyring */
#define KEY_SPEC_PROCESS_KEYRING -2 /* - key ID for process-specific keyring */
#define KEY_SPEC_SESSION_KEYRING -3 /* - key ID for session-specific keyring */
#define KEY_SPEC_USER_KEYRING -4 /* - key ID for UID-specific keyring */
#define KEY_SPEC_USER_SESSION_KEYRING -5 /* - key ID for UID-session keyring */
#define KEY_SPEC_GROUP_KEYRING -6 /* - key ID for GID-specific keyring */
#define KEY_SPEC_REQKEY_AUTH_KEY -7 /* - key ID for assumed request_key auth key */
#define KEY_SPEC_REQUESTOR_KEYRING -8 /* - key ID for request_key() dest keyring */
/* request-key default keyrings */
#define KEY_REQKEY_DEFL_NO_CHANGE -1
#define KEY_REQKEY_DEFL_DEFAULT 0
#define KEY_REQKEY_DEFL_THREAD_KEYRING 1
#define KEY_REQKEY_DEFL_PROCESS_KEYRING 2
#define KEY_REQKEY_DEFL_SESSION_KEYRING 3
#define KEY_REQKEY_DEFL_USER_KEYRING 4
#define KEY_REQKEY_DEFL_USER_SESSION_KEYRING 5
#define KEY_REQKEY_DEFL_GROUP_KEYRING 6
#define KEY_REQKEY_DEFL_REQUESTOR_KEYRING 7
/* keyctl commands */
#define KEYCTL_GET_KEYRING_ID 0 /* ask for a keyring's ID */
#define KEYCTL_JOIN_SESSION_KEYRING 1 /* join or start named session keyring */
#define KEYCTL_UPDATE 2 /* update a key */
#define KEYCTL_REVOKE 3 /* revoke a key */
#define KEYCTL_CHOWN 4 /* set ownership of a key */
#define KEYCTL_SETPERM 5 /* set perms on a key */
#define KEYCTL_DESCRIBE 6 /* describe a key */
#define KEYCTL_CLEAR 7 /* clear contents of a keyring */
#define KEYCTL_LINK 8 /* link a key into a keyring */
#define KEYCTL_UNLINK 9 /* unlink a key from a keyring */
#define KEYCTL_SEARCH 10 /* search for a key in a keyring */
#define KEYCTL_READ 11 /* read a key or keyring's contents */
#define KEYCTL_INSTANTIATE 12 /* instantiate a partially constructed key */
#define KEYCTL_NEGATE 13 /* negate a partially constructed key */
#define KEYCTL_SET_REQKEY_KEYRING 14 /* set default request-key keyring */
#define KEYCTL_SET_TIMEOUT 15 /* set key timeout */
#define KEYCTL_ASSUME_AUTHORITY 16 /* assume request_key() authorisation */
#define KEYCTL_GET_SECURITY 17 /* get key security label */
#define KEYCTL_SESSION_TO_PARENT 18 /* apply session keyring to parent process */
#define KEYCTL_REJECT 19 /* reject a partially constructed key */
#define KEYCTL_INSTANTIATE_IOV 20 /* instantiate a partially constructed key */
#define KEYCTL_INVALIDATE 21 /* invalidate a key */
#define KEYCTL_GET_PERSISTENT 22 /* get a user's persistent keyring */
#endif /* _LINUX_KEYCTL_H */