[lkml]   [2000]   [Sep]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH] mtrr: s/suser/capable/
Chris Evans writes:
> On Thu, 31 Aug 2000, Tigran Aivazian wrote:
> > Actually, microcode driver checks CAP_SYS_RAWIO only on open() so it would
> > allow access to the receiver of fd even he has no CAP_SYS_RAWIO
> > privilege. Hmmm, maybe I should put it back into write() method, as Linus
> > (or someone else) did at some point (and I removed it)...
> Please don't put it back into write(). One of the powerful uses of passing
> fds is across privilege boundaries. We don't want that to suddenly stop
> working.
> Look at it this way: if anyone passes a privileged fd, they either
> know what they are doing, or get what they deserve.

I agree. Firstly, you can't frob random memory with the MTRR driver,
so it clearly doesn't need CAP_SYS_RAWIO. Secondly, if a privileged
process (i.e. one which can open RW) wishes to pass the FD, then that
should be allowed.

Besides, we have this nice access control method in Unix: file
permissions. Why not use it?

So, I'm inclined to replace the calls to suser() with a check for
write access on the filp.


To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
Please read the FAQ at

 \ /
  Last update: 2005-03-22 12:38    [W:0.070 / U:0.684 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site