Re: [Qemu-devel] [PATCH 4/4] net: ignore packet size greater than INT_MAX

[Michael S. Tsirkin]

On Tue, Sep 25, 2018 at 03:23:27PM +0800, Jason Wang wrote:
> There should not be a reason for passing a packet size greater than
> INT_MAX. It's usually a hint of bug somewhere, so ignore packet size
> greater than INT_MAX in qemu_deliver_packet_iov()
> 
> CC: address@hidden
> Reported-by: Daniel Shapira <address@hidden>
> Signed-off-by: Jason Wang <address@hidden>
> ---
>  net/net.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/net/net.c b/net/net.c
> index fd8efebfdb..df216e3811 100644
> --- a/net/net.c
> +++ b/net/net.c
> @@ -712,10 +712,15 @@ ssize_t qemu_deliver_packet_iov(NetClientState *sender,
>                                  void *opaque)
>  {
>      NetClientState *nc = opaque;
> +    size_t size = iov_size(iov, iovcnt);
>      int ret;
>  

This adds a useless iov scan on the good path.
Can't be good for performance...

> +    if (size > INT_MAX) {
> +        return size;
> +    }
> +
>      if (nc->link_down) {
> -        return iov_size(iov, iovcnt);
> +        return size;
>      }
>  
>      if (nc->receive_disabled) {
> -- 
> 2.17.1