From: Prasad J Pandit <address@hidden>

Ne2000 NIC uses ring buffer of NE2000_MEM_SIZE(49152)

bytes to process network packets. Registers PSTART & PSTOP

define ring buffer size & location. Setting these registers

to invalid values could lead to infinite loop or OOB r/w

access issues. Add check to avoid it.

Reported-by: Yang Hongke <address@hidden>

Signed-off-by: Prasad J Pandit <address@hidden>

---

 hw/net/ne2000.c | 4 ++++

 1 file changed, 4 insertions(+)

Update per review:

  -> https://lists.gnu.org/archive/html/qemu-devel/2016-02/msg05522.html

diff --git a/hw/net/ne2000.c b/hw/net/ne2000.c

index b032212..ced4666 100644

--- a/tools/qemu-xen/hw/net/ne2000.c

+++ b/tools/qemu-xen/hw/net/ne2000.c

@@ -154,6 +154,10 @@ static int ne2000_buffer_full(NE2000State *s)

 {

     int avail, index, boundary;

+    if (s->stop <= s->start) {

+        return 1;

+    }

+

     index = s->curpag << 8;

     boundary = s->boundary << 8;

     if (index < boundary)

-- 

2.5.0