Re: [Qemu-devel] [PATCH v2] net: ne2000: check ring buffer control registers

[Jason Wang]

On 02/24/2016 02:11 PM, P J P wrote:
> From: Prasad J Pandit 
>
> 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 
> Signed-off-by: Prasad J Pandit 
> ---
>  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/hw/net/ne2000.c
> +++ b/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)

Hongke, would you mind to test this patch to see if it fixes your issue
and add a "Tested-by" tag?

Thanks

[Qemu-devel] [PATCH v2] net: ne2000: check ring buffer control registers

[P J P]

From: Prasad J Pandit 

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 
Signed-off-by: Prasad J Pandit 
---
 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/hw/net/ne2000.c
+++ b/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