Re: [PATCH] Introduce BSD-style user credential [3/3]

[Linus Torvalds]

On 31 Aug 2002, Alan Cox wrote:
>
> On Sat, 2002-08-31 at 01:49, Linus Torvalds wrote:
> > > struct pcred {
> > >        atomic_t	count;
> > >        uid_t	uid, euid, suid;
> > >        gid_t	gid, egid, sgid;
> > >        struct ucred  *cred;
> > >        kernel_cap_t ... capabilities ...
> > >        struct user_struct *user;
> > > };
> > 
> 
> Needs fsuid too, and space for the security LSM modules to attach
> private information. SELinux needs a few more credentials than base
> kernels!

Note that "fsuid" would _be_ the "struct ucred *" thing (but hopefully
renamed: "ucred" is a really bad name, since it has almost nothing to do
with the user, and has everything to do with VFS. I don't know where BSD
got the "u" from).

Think of "fsuid"  and "fsgid" as small special-case "filesystem
credentials" already - they're separate from the regular uid/gid because
they have different sharing semantics (uid/euid are visible to signals,
the FS credentials aren't).

So I dont' think that is a problem.

The issue about attaching additional credential information (both to the
user credentials _and_ to the VFS credentials) is true, though.

		Linus