Re: "Fix ATAPI transfer lengths" causes CD writing regression

Jeff Garzik
2007-10-31T16:06:14Z

Jens Axboe wrote:
> Right, that's of course problematic... There has to be a way to recover
> that situation though, or you can't export any user command issue
> facility.

You cannot hope to handle all possible effects arising from an app
providing an invalid sg header / cdb.

Once you start talking "recovery" you are already screwed: we are
talking about low-level hardware commands that are passed straight to
the hardware. It is trivial to lock up hardware, brick hardware, and
corrupt data at that level.

If this is NOT a privileged app, we must update the command validation
to ensure that invalid commands are not transported to the hardware.

If this is a privileged app, our work is done. Fix the app. We gave
root rope, and he took it.

I even venture to say that "accept anything, clean up afterwards" is
/impossible/ to implement, in addition to being dangerous.

Jeff