Re: [RFC] list of SCSI commands

[Andreas Messer]

Hello,

On Tue, Aug 17, 2004 at 07:27:48PM +0200, Marc Ballarin wrote:
> Hi,
> I think the filtering mechanism needs to be refined before we can do
> useful patches. I think it will be necessary to base filtering on
> scsi_type from struct sg_scsi_id (in sg.h and scsi.h). Otherwise it will
> be impossible to get functionality and safety for all devices.

Yes, but some people want to use 2.6.8.1 instead of 2.6.7 (NFS security 
problem) and i only want to provide a short patch to get the old behavior.
Like You, i think  there should be device-class depend accesscontrol-lists. 
But this will need more performance. As there are not that many device 
classes, i would suggest to make one verify-function per device class and 
put a pointer in the file-struct, which will point to the suggested function

> 
> I have compiled a long list of various SCSI commands and tried to
> categorize them. This list is focused on mmc devices (CD-RW, DVD+R).
> Many commands that are only relevant for discs are not included.
> 
> =UNCLEAR=
> MODE SELECT should be safe for mmc devices (sometimes even required).
> However, it often is *not* safe for other devices. This is a case,
> were filtering needs to honor device types.
> 0x15	MODE_SELECT
> 0x55	MODE_SELECT_10
> 0x01	REZERO_UNIT

Yes, this is really a problem.

> I haven't found further information on the following commands. Some are
> probably vendor specific. Annotations are from cdrecord.

Hmm, perhaps i should compare them against the mmc4-spec? They might do 
nothing with mmc-drives?

> =WRITE=
> 0x04	FORMAT_UNIT	// is this safe for disks?

No, according to sbc2-spec it will format the entire harddisc.

> =RAWIO=
> Some modes of WRITE_BUFFER are safe even for read, others
> overwrite firmware. Misdesign.
> 0x3B	WRITE_BUFFER

According to spc3-spec (mentioned in sbc2) it will only used 
to check performance of the device or programm the firmware


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