Re: [PATCH net-next v6 15/21] ip_tunnel: use a separate struct to store tunnel params in the kernel

[Dan Carpenter]

On Wed, Mar 27, 2024 at 04:23:52PM +0100, Alexander Lobakin wrote:
> +bool ip_tunnel_parm_to_user(void __user *data, struct ip_tunnel_parm_kern *kp)
> +{
> +	struct ip_tunnel_parm p;
> +
> +	strscpy(p.name, kp->name);

We need to clear out p before copying to user space to avoid an
information leak.  So this strscpy() needs to be strcpy_pad()

> +	p.link = kp->link;
> +	p.i_flags = kp->i_flags;
> +	p.o_flags = kp->o_flags;
> +	p.i_key = kp->i_key;
> +	p.o_key = kp->o_key;
> +	memcpy(&p.iph, &kp->iph, min(sizeof(p.iph), sizeof(kp->iph)));

And this memcpy() doesn't necessarily clear the whole of p.iph.

> +
> +	return !copy_to_user(data, &p, sizeof(p));
> +}

regards,
dan carpenter