Re: [Qemu-devel] [PATCH] net: vmxnet: check fragments count at pkt initialisation

[Dmitry Fleytman]

Acked-by: Dmitry Fleytman <address@hidden>

> On 10 Aug 2016, at 23:38 PM, P J P <address@hidden> wrote:
> 
> From: Li Qiang <address@hidden>
> 
> When net transport abstraction layer initialises the pkt,
> the maximum fragmentation count is not checked. This could
> lead to an integer overflow causing a NULL pointer dereference.
> Add check to avoid it.
> 
> Reported-by: Li Qiang <address@hidden>
> Signed-off-by: Prasad J Pandit <address@hidden>
> ---
> hw/net/net_tx_pkt.c | 3 +++
> 1 file changed, 3 insertions(+)
> 
> diff --git a/hw/net/net_tx_pkt.c b/hw/net/net_tx_pkt.c
> index 53dfaa2..7ea3c17 100644
> --- a/hw/net/net_tx_pkt.c
> +++ b/hw/net/net_tx_pkt.c
> @@ -58,9 +58,12 @@ struct NetTxPkt {
>     bool is_loopback;
> };
> 
> +#define NET_PKT_MAX_FRAGS    16  /* ref: MAX_SKB_FRAGS in kernel driver */
> +
> void net_tx_pkt_init(struct NetTxPkt **pkt, PCIDevice *pci_dev,
>     uint32_t max_frags, bool has_virt_hdr)
> {
> +    assert(max_frags <= NET_PKT_MAX_FRAGS);
>     struct NetTxPkt *p = g_malloc0(sizeof *p);
> 
>     p->pci_dev = pci_dev;
> -- 
> 2.5.5
>