Re: [PATCH net-next 02/20] netlink: Add extack message to nlmsg_parse for invalid header length

From: Christian Brauner <christian@brauner.io>
To: David Ahern <dsahern@kernel.org>
Cc: netdev@vger.kernel.org, davem@davemloft.net, jbenc@redhat.com,
	stephen@networkplumber.org, David Ahern <dsahern@gmail.com>
Subject: Re: [PATCH net-next 02/20] netlink: Add extack message to nlmsg_parse for invalid header length
Date: Fri, 5 Oct 2018 19:41:52 +0200	[thread overview]
Message-ID: <20181005174152.ktj5cha4zjmxyhcz@brauner.io> (raw)
In-Reply-To: <20181004213355.14899-3-dsahern@kernel.org>

On Thu, Oct 04, 2018 at 02:33:37PM -0700, David Ahern wrote:
> From: David Ahern <dsahern@gmail.com>
> 
> Give a user a reason why EINVAL is returned in nlmsg_parse.
> 
> Signed-off-by: David Ahern <dsahern@gmail.com>

Acked-by: Christian Brauner <christian@brauner.io>

> ---
>  include/net/netlink.h | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/include/net/netlink.h b/include/net/netlink.h
> index 589683091f16..9522a0bf1f3a 100644
> --- a/include/net/netlink.h
> +++ b/include/net/netlink.h
> @@ -516,8 +516,10 @@ static inline int nlmsg_parse(const struct nlmsghdr *nlh, int hdrlen,
>  			      const struct nla_policy *policy,
>  			      struct netlink_ext_ack *extack)
>  {
> -	if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
> +	if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen)) {
> +		NL_SET_ERR_MSG(extack, "Invalid header length");
>  		return -EINVAL;
> +	}
>  
>  	return nla_parse(tb, maxtype, nlmsg_attrdata(nlh, hdrlen),
>  			 nlmsg_attrlen(nlh, hdrlen), policy, extack);
> -- 
> 2.11.0
>