linux/security/selinux
David Howells 3a3b7ce933 CRED: Allow kernel services to override LSM settings for task actions
Allow kernel services to override LSM settings appropriate to the actions
performed by a task by duplicating a set of credentials, modifying it and then
using task_struct::cred to point to it when performing operations on behalf of
a task.

This is used, for example, by CacheFiles which has to transparently access the
cache on behalf of a process that thinks it is doing, say, NFS accesses with a
potentially inappropriate (with respect to accessing the cache) set of
credentials.

This patch provides two LSM hooks for modifying a task security record:

 (*) security_kernel_act_as() which allows modification of the security datum
     with which a task acts on other objects (most notably files).

 (*) security_kernel_create_files_as() which allows modification of the
     security datum that is used to initialise the security data on a file that
     a task creates.

The patch also provides four new credentials handling functions, which wrap the
LSM functions:

 (1) prepare_kernel_cred()

     Prepare a set of credentials for a kernel service to use, based either on
     a daemon's credentials or on init_cred.  All the keyrings are cleared.

 (2) set_security_override()

     Set the LSM security ID in a set of credentials to a specific security
     context, assuming permission from the LSM policy.

 (3) set_security_override_from_ctx()

     As (2), but takes the security context as a string.

 (4) set_create_files_as()

     Set the file creation LSM security ID in a set of credentials to be the
     same as that on a particular inode.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> [Smack changes]
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-14 10:39:28 +11:00
..
include CRED: Add a kernel_service object class to SELinux 2008-11-14 10:39:27 +11:00
ss Merge branch 'master' of git://git.infradead.org/users/pcmoore/lblnet-2.6_next into next 2008-10-11 09:26:14 +11:00
avc.c SELinux: add boundary support and thread context assignment 2008-08-29 00:33:33 +10:00
exports.c CRED: Wrap current->cred and a few other accessors 2008-11-14 10:39:18 +11:00
hooks.c CRED: Allow kernel services to override LSM settings for task actions 2008-11-14 10:39:28 +11:00
Kconfig Update selinux info in MAINTAINERS and Kconfig help text 2008-09-12 00:44:08 +10:00
Makefile SELinux: Add network port SID cache 2008-04-18 20:26:16 +10:00
netif.c SELinux fixups needed for preemptable RCU from -rt 2008-04-22 15:37:23 +10:00
netlabel.c selinux: Cache NetLabel secattrs in the socket's security struct 2008-10-10 10:16:33 -04:00
netlink.c SELinux: netlink.c whitespace, syntax, and static declaraction cleanups 2008-04-21 19:05:05 +10:00
netnode.c SELinux: keep the code clean formating and syntax 2008-07-14 15:01:36 +10:00
netport.c SELinux: keep the code clean formating and syntax 2008-07-14 15:01:36 +10:00
nlmsgtab.c selinux: recognize netlink messages for 'ip addrlabel' 2008-11-06 07:08:36 +08:00
selinuxfs.c CRED: Use RCU to access another task's creds and to release a task's own creds 2008-11-14 10:39:19 +11:00
xfrm.c CRED: Wrap current->cred and a few other accessors 2008-11-14 10:39:18 +11:00