Re: [Xen-devel] Why cannot HVM open a file as a floopy disk?

[Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>]

Akio Takebe writes ("Re: [Xen-devel] Why cannot HVM open a file as a floopy 
disk?"):
> Thank you very much for your elaborating.
> We usually use /dev/floppy of dom0 as floppy disk of guest.

Right, and the code specifically checks whether the backing object in
dom0 is a block device, and if so treats it unconditionally as raw.

> So a raw format floppy disk is not important.

I'm not sure what you're saying ?  I asked:
  Does anyone use Xen with non-raw floppy disk images in disk files ?

> The restriction is reasonable, but xend would need to be fixed
> because it hangup.

The error handling is appallingly bad, I'm afraid.

> Also I concern about a emulate ide disk of the raw format.
> Is it also vulnerable?

No, there are no vulnerabilities of this kind in our tree - precisely
because of the refusal of the format-guessing algorithm to return
`raw', which is a change I introduced.  The effect is that any attempt
to provide a raw image, in circumstances where the code attempts to
guess the format, fails.

In upstream qemu the default configuration is vulnerable, I think, for
most block devices, but I haven't double-checked the latest code.  On
the other hand in general in recent upstream qemu it is always
possible to specify the format, elminating the problem.

Ian.

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