Re: [Patch] allow file truncations when both suid and write permissions set

[Amerigo Wang <amwang@redhat.com>]

Eric Paris wrote:
> So NAK on both Amerigo's and Eric's patch.  ATTR_FORCE is wrong.
> ATTR_FORCE here is going to force the security system to accept ALL of
> the attr changes, not just the ATTR_KILL_SUID and/or ATTR_KILL_SGID you
> |= in from should_remove_suid.
> You need to follow esandeen's recommendation, change file_remove_suid()
> to dentry_remove_suid() and then use dentry_remove_suid() in do_truncate
> instead of what you are currently trying to do (and I think that's
> supposed to be done under the i_mutex right?)
>   
But file_remove_suid() actually adds ATTR_FORCE too, in __remove_suid()...