[Qemu-devel] Re: [PATCH 2/4] Add virtio disk identification support

[Anthony Liguori <anthony@codemonkey.ws>]

On 03/25/2010 12:33 AM, john cooper wrote:
> Fix bug which truncated serial string to 8 bytes, nul terminate.
>
> Signed-off-by: john cooper<john.cooper@redhat.com>
> ---
>
> diff --git a/vl.c b/vl.c
> index d69250c..b74cbba 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -1162,7 +1162,7 @@ DriveInfo *drive_init(QemuOpts *opts, void *opaque,
>       dinfo->on_write_error = on_write_error;
>       dinfo->opts = opts;
>       if (serial)
> -        strncpy(dinfo->serial, serial, sizeof(serial));
> +        strncpy(dinfo->serial, serial, sizeof(dinfo->serial) - 1);
>    

You need to explicitly add a null terminator.  Far better to just never 
use strncpy().

Regards,

Anthony Liguori

>       QTAILQ_INSERT_TAIL(&drives, dinfo, next);
>
>       switch(type) {
>
>