Re: PATCH: cdrecord: avoiding scsi device numbering for ide devices

Alan Cox
2004-08-20T12:26:17Z

On Iau, 2004-08-19 at 23:57, Bartlomiej Zolnierkiewicz wrote:
> Alan's example is invalid because IDE driver requires CAP_SYS_ADMIN and
> CAP_SYS_RAWIO so if there is some security risk involved - it is in the user
> apps not in the kernel. Also Linus first fixed SG_IO correctly with
> requiring CAP_SYS_RAWIO but then (under Alan's influence?) he added filtering
> which broke cd writing and which is just unmaintainable.

SG_IO prior to 2.6.8 doesn't do any checks on any path into and through
the IDE driver. Thus I sent Linus a patch for 2.6.8 that just added
capable(CAP_SYS_RAWIO) to the raw command path.

Filtering was something Jens and I were talking about. I was a little
suprised when Linus added filters just before release. We do now have
good traces of what various apps want. Some of those commands may be
problematic without sg_io knowing the target class however.

> Also filtering cannot work in all cases because there are vendor specific
> opcodes, some devices redefines some opcodes etc. - this should be left to
> user space.

Possibly. Vendor commands are not in themselves a problems. The answer
to those is "no" 8)