netdev - Re: [PATCH v2 net-next 19/23] net/ipv6: Update ip6addrlbl

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Message-ID: <20181008105150.qzq3akbfuaeprzp5@brauner.io>
Date:   Mon, 8 Oct 2018 12:51:50 +0200
From:   Christian Brauner <christian@...uner.io>
To:     David Ahern <dsahern@...nel.org>
Cc:     netdev@...r.kernel.org, davem@...emloft.net, jbenc@...hat.com,
        stephen@...workplumber.org, David Ahern <dsahern@...il.com>
Subject: Re: [PATCH v2 net-next 19/23] net/ipv6: Update ip6addrlbl_dump for
 strict data checking

On Sun, Oct 07, 2018 at 08:16:40PM -0700, David Ahern wrote:
> From: David Ahern <dsahern@...il.com>
> 
> Update ip6addrlbl_dump for strict data checking. If the flag is set,
> the dump request is expected to have an ifaddrlblmsg struct as the
> header. All elements of the struct are expected to be 0 and no
> attributes can be appended.
> 
> Signed-off-by: David Ahern <dsahern@...il.com>

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

> ---
>  net/ipv6/addrlabel.c | 34 +++++++++++++++++++++++++++++++++-
>  1 file changed, 33 insertions(+), 1 deletion(-)
> 
> diff --git a/net/ipv6/addrlabel.c b/net/ipv6/addrlabel.c
> index 1d6ced37ad71..0d1ee82ee55b 100644
> --- a/net/ipv6/addrlabel.c
> +++ b/net/ipv6/addrlabel.c
> @@ -458,20 +458,52 @@ static int ip6addrlbl_fill(struct sk_buff *skb,
>  	return 0;
>  }
>  
> +static int ip6addrlbl_valid_dump_req(const struct nlmsghdr *nlh,
> +				     struct netlink_ext_ack *extack)
> +{
> +	struct ifaddrlblmsg *ifal;
> +
> +	if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*ifal))) {
> +		NL_SET_ERR_MSG_MOD(extack, "Invalid header for address label dump request");
> +		return -EINVAL;
> +	}
> +
> +	ifal = nlmsg_data(nlh);
> +	if (ifal->__ifal_reserved || ifal->ifal_prefixlen ||
> +	    ifal->ifal_flags || ifal->ifal_index || ifal->ifal_seq) {
> +		NL_SET_ERR_MSG_MOD(extack, "Invalid values in header for address label dump request");
> +		return -EINVAL;
> +	}
> +
> +	if (nlmsg_attrlen(nlh, sizeof(*ifal))) {
> +		NL_SET_ERR_MSG_MOD(extack, "Invalid data after header for address label dump requewst");
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
>  static int ip6addrlbl_dump(struct sk_buff *skb, struct netlink_callback *cb)
>  {
> +	const struct nlmsghdr *nlh = cb->nlh;
>  	struct net *net = sock_net(skb->sk);
>  	struct ip6addrlbl_entry *p;
>  	int idx = 0, s_idx = cb->args[0];
>  	int err;
>  
> +	if (cb->strict_check) {
> +		err = ip6addrlbl_valid_dump_req(nlh, cb->extack);
> +		if (err < 0)
> +			return err;
> +	}
> +
>  	rcu_read_lock();
>  	hlist_for_each_entry_rcu(p, &net->ipv6.ip6addrlbl_table.head, list) {
>  		if (idx >= s_idx) {
>  			err = ip6addrlbl_fill(skb, p,
>  					      net->ipv6.ip6addrlbl_table.seq,
>  					      NETLINK_CB(cb->skb).portid,
> -					      cb->nlh->nlmsg_seq,
> +					      nlh->nlmsg_seq,
>  					      RTM_NEWADDRLABEL,
>  					      NLM_F_MULTI);
>  			if (err < 0)
> -- 
> 2.11.0
>