Messages in this thread |  | | Date | Fri, 1 Sep 2000 07:31:57 -0600 | From | Richard Gooch <> | Subject | Re: [PATCH] mtrr: s/suser/capable/ |
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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.
Regards,
Richard.... Permanent: rgooch@atnf.csiro.au Current: rgooch@ras.ucalgary.ca - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/
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