Re: [Qemu-devel] [PATCH] e1000: bounds packet size against buffer size

[Michael Tokarev]

On 02.02.2012 15:15, Stefano Stabellini wrote:
> On Mon, 23 Jan 2012, Anthony Liguori wrote:
>> Otherwise we can write beyond the buffer and corrupt memory.  This is tracked
>> as CVE-2012-0029.
> 
> The stable-1.0 branch looks vulnerable too, shouldn't this patch be
> backported?

This goes on since forever - for example, this patch applies to 0.12
too (modulo pci_dma_read() changes which makes the context differ).
It applies cleanly to 1.0 stable.

/mjt

>> Signed-off-by: Anthony Liguori <address@hidden>
>> ---
>>  hw/e1000.c |    3 +++
>>  1 files changed, 3 insertions(+), 0 deletions(-)
>>
>> diff --git a/hw/e1000.c b/hw/e1000.c
>> index a29c944..86c5416 100644
>> --- a/hw/e1000.c
>> +++ b/hw/e1000.c
>> @@ -466,6 +466,8 @@ process_tx_desc(E1000State *s, struct e1000_tx_desc *dp)
>>              bytes = split_size;
>>              if (tp->size + bytes > msh)
>>                  bytes = msh - tp->size;
>> +
>> +            bytes = MIN(sizeof(tp->data) - tp->size, bytes);
>>              pci_dma_read(&s->dev, addr, tp->data + tp->size, bytes);
>>              if ((sz = tp->size + bytes) >= hdr && tp->size < hdr)
>>                  memmove(tp->header, tp->data, hdr);
>> @@ -481,6 +483,7 @@ process_tx_desc(E1000State *s, struct e1000_tx_desc *dp)
>>          // context descriptor TSE is not set, while data descriptor TSE is 
>> set
>>          DBGOUT(TXERR, "TCP segmentaion Error\n");
>>      } else {
>> +        split_size = MIN(sizeof(tp->data) - tp->size, split_size);
>>          pci_dma_read(&s->dev, addr, tp->data + tp->size, split_size);
>>          tp->size += split_size;
>>      }
>> -- 
>> 1.7.4.1
>>
>>
>