Re: [Qemu-devel] [PATCH 1/2] net: pcnet: check rx/tx descriptor ring length

[Jason Wang]

On 2016年09月30日 02:57, P J P wrote:
> From: Prasad J Pandit <address@hidden>
>
> 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).

> Reported-by: Li Qiang <address@hidden>
> Signed-off-by: Prasad J Pandit <address@hidden>
> ---
>   hw/net/pcnet.c | 3 +++
>   1 file changed, 3 insertions(+)
>
> diff --git a/hw/net/pcnet.c b/hw/net/pcnet.c
> index 198a01f..3078de8 100644
> --- a/hw/net/pcnet.c
> +++ b/hw/net/pcnet.c
> @@ -1429,8 +1429,11 @@ static void pcnet_csr_writew(PCNetState *s, uint32_t 
> rap, uint32_t new_value)
>       case 47: /* POLLINT */
>       case 72:
>       case 74:
> +        break;
>       case 76: /* RCVRL */
>       case 78: /* XMTRL */
> +        val = (val > 0) ? val : 512;
> +        break;
>       case 112:
>          if (CSR_STOP(s) || CSR_SPND(s))
>              break;