Re: [Xen-devel] [Qemu-devel] [PATCH] xen-disk: use g_malloc0 to fix build

[Eric Blake <eblake@xxxxxxxxxx>]

On 07/28/2017 07:31 AM, Olaf Hering wrote:
> g_malloc0_n is available since glib-2.24. To allow build with older glib
> versions use the generic g_malloc0, which is already used in many other
> places in the code.
> 
> Fixes commit 3284fad728 ("xen-disk: add support for multi-page shared rings")
> 
> Signed-off-by: Olaf Hering <olaf@xxxxxxxxx>
> ---
>  hw/block/xen_disk.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/hw/block/xen_disk.c b/hw/block/xen_disk.c
> index d42ed7070d..71deec17b0 100644
> --- a/hw/block/xen_disk.c
> +++ b/hw/block/xen_disk.c
> @@ -1232,7 +1232,7 @@ static int blk_connect(struct XenDevice *xendev)
>          return -1;
>      }
>  
> -    domids = g_malloc0_n(blkdev->nr_ring_ref, sizeof(uint32_t));
> +    domids = g_malloc0(blkdev->nr_ring_ref * sizeof(uint32_t));

This version is prone to multiplication overflow (well, maybe not, but
you have to audit for that).  Wouldn't it be better to use:

domids = g_new0(blkdev->nr_ring_ref, uint32_t)

which preserves the safety of g_malloc0_n?


-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org

Attachment: signature.asc
Description: OpenPGP digital signature

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
https://lists.xen.org/xen-devel