AppArmor security module overview

This post contains patches to include the AppArmor application security framework, with request for inclusion into -mm for wider testing.

These patches are currently against lkml but we will gladly rebase them against -mm so that they will apply cleanly.

Any comments and feedback to improve implementation are appreciated.

A second post dealing with the issue of passing NULL nameidata, will be posted to lkml for discussion.

Changes since previous post:
- remove custom pathname mangling
- rework apparmor auditing to cleanup message formating and better use audit framework
- change permission consistency checks from runtime to once at policy load
- add change_profile feature and cleanup change_hat to use change_profile

The patch series consists of five areas:

(1) Pass struct vfsmount through to LSM hooks.

(2) Fixes and improvements to __d_path():

(a) make it unambiguous and exclude unreachable paths from /proc/mounts,

(b) make its result consistent in the face of remounts,

(c) introduce d_namespace_path(), a variant of d_path that goes up to the namespace root instead of the chroot.

(d) the behavior of d_path() and getcwd() remain unchanged, and there is no hidding of unreachable paths in /proc/mounts. The patches addressing these have been seperated from the AppArmor submission and will be introduced at a later date.

Part (a) has been in the -mm tree for a while; this series includes an updated copy of the -mm patch. Parts (b) and (c) shouldn't be too controversial.

(3) Be able to distinguish file descriptor access from access by name in LSM hooks.

Applications expect different behavior from file descriptor accesses and accesses by name in some cases. We need to pass this information down the LSM hooks to allow AppArmor to tell which is which.

(4) Convert the selinux sysctl pathname computation code into a standalone function.

(5) The AppArmor LSM itself.

(See below.)

A tarball of the kernel patches, base user-space utilities, example profiles, and technical documentation (including a walk-through) are available at:

http://forgeftp.novell.com//apparmor/LKML_Submission-June-07/

Explaining the AppArmor design in detail would take by far too much space here, so let me refer you to the technical documentation for that. Included is a low-level walk-through of the system and basic tools, and some examples. The manual pages included in the apparmor-parser package are worth a read as well.