Re: setfs[ug]id syscall return value and include/linux/security.h question

[Chris Wright <chris@wirex.com>]

* Jakub Jelinek (jakub@redhat.com) wrote:
> Hi!
> 
> Before include/linux/security.h was added, setfsuid/setfsgid always returned
> old_fsuid, no matter if the fsuid was actually changed or not.
> With the default security ops it seems to do the same, because both
> security_task_setuid and security_task_post_setuid return 0, but these are
> hooks which seem to return 0 on success, -errno on failure, so if some
> non-default security hook is installed and ever returns -errno
> in setfsuid/setfsgid, -errno will be returned from the syscall instead
> of the expected old_fsuid. This makes it hard to distinguish uids
> 0xfffff001 .. 0xffffffff from errors of security hooks.
> Shouldn't sys_setfsuid/sys_setfsgid be changed:

Yes, thanks for the patch.  I'll apply this to the LSM tree and push to
Linus with the next batch of changes.  It's unfortunate that the
sys_setfs[ug]id interface can't report an error.

thanks,
-chris
-- 
Linux Security Modules     http://lsm.immunix.org     http://lsm.bkbits.net