Hello Jason,
+-- On Fri, 30 Sep 2016, Jason Wang wrote --+
| On 2016年09月30日 02:57, P J P wrote:
| > The AMD PC-Net II emulator has set of control and status(CSR)
| > registers. Of these, CSR76 and CSR78 hold receive and transmit
| > descriptor ring length respectively. This ring length could range
| > from 1 to 65535. Setting ring length to zero leads to an infinite
| > loop in pcnet_rdra_addr. Add check to avoid it.
|
| In this case, we only need to protect RCVRL I believe? (since XMTRL were not
| used).
XMTRL is not used in this case, but could be prone to similar issues. For
ex.
static void pcnet_transmit(PCNetState *s)
{
int count = CSR_XMTRL(s) - 1;
...
if (count--)
goto txagain;
}
If CSR_XMTRL is set to zero(0), 'count' would never reach zero and function
would continue to jump to 'txagain'.
Thank you.
--
Prasad J Pandit / Red Hat Product Security Team
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