Re: [Qemu-devel] [Qemu-block] [QEMU-SECURITY] ide: fix assertion in ide_dma_cb() to prevent qemu DoS from quest

[Kevin Wolf]

Am 15.07.2019 um 13:24 hat Alexander Popov geschrieben:
> On 05.07.2019 17:07, Alexander Popov wrote:
> > This assertion was introduced in the commit a718978ed58a in July 2015.
> > It implies that the size of successful DMA transfers handled in
> > ide_dma_cb() should be multiple of 512 (the size of a sector).
> > 
> > But guest systems can initiate DMA transfers that don't fit this
> > requirement. Let's improve the assertion to prevent qemu DoS from quests.
> 
> Hello!
> 
> Just a friendly ping.
> 
> Could you have a look at this patch?

John, I think this is for you.

I haven't reviewed this yet, but if we put an assertion there that the
request is aligned, we probably rely on this fact somewhere in the code.
So I suspect that just changing the assertion without changing other
code, too, might not be enough.

Kevin