Re: [PATCH] e1000: fix tx re-entrancy problem

[Jon Maloy <jmaloy@redhat.com>]

On 12/16/21 04:36, Philippe Mathieu-Daudé wrote:
> Hi Jon,
>
> On 10/21/21 18:10, Jon Maloy wrote:
>> The fact that the MMIO handler is not re-entrant causes an infinite
>> loop under certain conditions:
>>
>> Guest write to TDT ->  Loopback -> RX (DMA to TDT) -> TX
>>
>> We now eliminate the effect of this problem locally in e1000, by adding
>> a boolean in struct E1000State indicating when the TX side is busy. This
>> will cause any entering new call to return early instead of interfering
>> with the ongoing work, and eliminates any risk of looping.
>>
>> This is intended to address CVE-2021-20257.
>>
>> Signed-off-by: Jon Maloy <jmaloy@redhat.com>
>> ---
>>   hw/net/e1000.c | 7 +++++++
>>   1 file changed, 7 insertions(+)
> I can not find the reproducer in the repository, have you sent one?
>
No, I did not add it to the repo.
It was referenced from the tracker BZ, but I was unable to get access 
back then.
It ended up with that I had it sent by mail to me directly.

What is your question? Is it that it should be in the repo, or that you 
cannot find it?

///jon