Re: [Qemu-devel] [PATCH 2/2] linux-user: Correct type for BLKSSZGET

[Laurent Vivier]

Le 04/07/2016 à 18:06, Peter Maydell a écrit :
> The BLKSSZGET ioctl takes an argument which is a pointer to an int.
> We were incorrectly declaring it to take a pointer to a long, which
> meant that we would incorrectly write to memory which we should not
> if the guest is a 64-bit architecture.
> 
> In particular, kpartx uses this ioctl to write to an int on the
> stack, which tends to result in it crashing immediately.
> 
> Reported-by: Chanho Park <address@hidden>
> Signed-off-by: Peter Maydell <address@hidden>

Reviewed-by: Laurent Vivier <address@hidden>

> ---
>  linux-user/ioctls.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/linux-user/ioctls.h b/linux-user/ioctls.h
> index 72cd32a..8978eb3 100644
> --- a/linux-user/ioctls.h
> +++ b/linux-user/ioctls.h
> @@ -76,7 +76,7 @@
>       IOCTL(BLKFLSBUF, 0, TYPE_NULL)
>       IOCTL(BLKRASET, 0, TYPE_INT)
>       IOCTL(BLKRAGET, IOC_R, MK_PTR(TYPE_LONG))
> -     IOCTL(BLKSSZGET, IOC_R, MK_PTR(TYPE_LONG))
> +     IOCTL(BLKSSZGET, IOC_R, MK_PTR(TYPE_INT))
>       IOCTL(BLKBSZGET, IOC_R, MK_PTR(TYPE_INT))
>       IOCTL_SPECIAL(BLKPG, IOC_W, do_ioctl_blkpg,
>                     MK_PTR(MK_STRUCT(STRUCT_blkpg_ioctl_arg)))
>