Re: Credentials test patch

From: Casey Schaufler
Date: Tue Sep 18 2007 - 13:58:54 EST



--- Trond Myklebust <trond.myklebust@xxxxxxxxxx> wrote:

> On Tue, 2007-09-18 at 17:33 +0100, David Howells wrote:
> > Hi Al, Christoph,
> >
> > Here's a new version of my credentials patch. It's still very basic, with
> > only Ext3, (V)FAT, NFS, AFS, SELinux and keyrings compiled in on an x86_64
> > arch kernel. The patched kernel compiles, links and runs.
> >
> > I've made the following major changes to the patch:
> >
> > (1) System calls that might want to use the credentials call
> > update_current_cred() before calling into the VFS or whatever. This
> > allows the keyring pointers in the cred struct to be updated.
> >
> > (2) I've got rid of current_cred(), __current_cred() and the accessors for
> > current's fsuid, fsgid and group list. Instead you just use
> > current->cred->whatever. You don't need RCU to read the current
> threads
> > credentials as only you are permitted to change them.
> >
> > David
> > ---
>
> What about the process' capabilities? Shouldn't they also be part of a
> credential?

As should the LSM security blob, if appropriate.

What I don't really understand is what value is gained by this exercise.
Are the savings sufficiently significant to justify the effort?


Casey Schaufler
casey@xxxxxxxxxxxxxxxx
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