Re: Is CAP_SYS_ADMIN checked by every program !?

[Stephen Smalley]

On Thu, 2004-12-30 at 02:40, Tetsuo Handa wrote:
> I'm developing a kernel patch that provides simple and handy
> MAC(mandatory access control) functionality, much easier than SELinux.
> And now I'm porting the patch from 2.4 to 2.6,
> though the patch can't support LSM, for it refers 'struct vfsmount'.
> 
> At first, I doubted that some kernel function (do_execve(), memory management
> functions, or any kernel functions that are always called by every process) is
> doing this CAP_SYS_ADMIN checking. But may be this CAP_SYS_ADMIN checking is
> caused by the Fedora Core 3's libc, not by the kernel.
> I don't have 2.6 kernel environment other than Fedora Core 3.
> 
> But anyway, I have to give up checking for CAP_SYS_ADMIN .

Just override the vm_enough_memory security hook with your own function,
as we do in SELinux, to avoid auditing the CAP_SYS_ADMIN check there.
Note that this issue has also come up again on the linux-security-module
mailing list recently, and might be addressed through a change to the
cap_vm_enough_memory hook function.

-- 
Stephen Smalley <sds@xxxxxxxxxxxxxx>
National Security Agency

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