From: Prasad J Pandit <pjp@fedoraproject.org>

Date: Fri, 30 Sep 2016 00:27:33 +0530

Subject: [PATCH] net: pcnet: check rx/tx descriptor ring length

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() or pcnet_transmit(). Add check to avoid it.

Reported-by: Li Qiang <liqiang6-s@360.cn>

Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>

Signed-off-by: Jason Wang <jasowang@redhat.com>

(cherry picked from commit 34e29ce754c02bb6b3bdd244fbb85033460feaff)

---

 hw/net/pcnet.c | 3 +++

 1 file changed, 3 insertions(+)

diff --git a/hw/net/pcnet.c b/hw/net/pcnet.c

index 198a01f92d..3078de8aba 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;