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 <p...@fedoraproject.org>

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 <liqiang...@360.cn>
Signed-off-by: Prasad J Pandit <p...@fedoraproject.org>
---
  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;