Re: [Qemu-devel] [RFC] fix crashes with vmware driver

[Ryan Harper <ryanh@us.ibm.com>]

* Serge Hallyn <serge.hallyn@canonical.com> [2012-03-02 15:13]:
> Hi,
> 
> I don't know where the best place to catch this would be, but
> with vnc and vmware_vga it's possible to get set_bit called on
> a negative index, crashing qemu.  See
> 
> https://bugs.launchpad.net/ubuntu/+source/qemu-kvm/+bug/918791
> 
> for details.  This patch prevents that.  It's possible this
> should be caught earlier, but this patch works for me.
> 
> Signed-off-by: Serge Hallyn <serge.hallyn@canonical.com>
> ---
>  vmware_vga.c |   16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> Index: qemu-kvm-1.0+noroms/hw/vmware_vga.c
> ===================================================================
> --- qemu-kvm-1.0+noroms.orig/hw/vmware_vga.c	2012-03-01 16:19:23.280571798 -0600
> +++ qemu-kvm-1.0+noroms/hw/vmware_vga.c	2012-03-01 16:27:27.910975006 -0600
> @@ -298,6 +298,22 @@
>      uint8_t *src;
>      uint8_t *dst;
> 
> +    if (x < 0) {
> +        fprintf(stderr, "%s: update x was < 0 (%d, w %d)\n",
> +                        __FUNCTION__, x, w);
> +        w += x;
> +	if (w < 0)
> +		return;
> +        x = 0;
> +    }
> +    if (y < 0) {
> +        fprintf(stderr, "%s: update y was < 0 (%d, h %d)\n",
> +                        __FUNCTION__, y, h);
> +        h += y;
> +	if (h < 0)
> +		return;
> +        y = 0;
> +    }

Looks like it has mixed spaces and tabs.

CODING_STYLE wants {} on all if's 



>      if (x + w > s->width) {
>          fprintf(stderr, "%s: update width too large x: %d, w: %d\n",
>                          __FUNCTION__, x, w);

-- 
Ryan Harper
Software Engineer; Linux Technology Center
IBM Corp., Austin, Tx
ryanh@us.ibm.com