On Thu, Oct 04, 2018 at 02:33:52PM -0700, David Ahern wrote:
> From: David Ahern <dsah...@gmail.com>
>
> Update fib_nl_dumprule for strict data checking. If the flag is set,
> the dump request is expected to have fib_rule_hdr 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 <dsah...@gmail.com>
Acked-by: Christian Brauner <christ...@brauner.io>
> ---
> net/core/fib_rules.c | 36 +++++++++++++++++++++++++++++++++++-
> 1 file changed, 35 insertions(+), 1 deletion(-)
>
> diff --git a/net/core/fib_rules.c b/net/core/fib_rules.c
> index 0ff3953f64aa..e3cf50728d0a 100644
> --- a/net/core/fib_rules.c
> +++ b/net/core/fib_rules.c
> @@ -1063,13 +1063,47 @@ static int dump_rules(struct sk_buff *skb, struct
> netlink_callback *cb,
> return err;
> }
>
> +static int fib_valid_dumprule(const struct nlmsghdr *nlh,
> + struct netlink_ext_ack *extack)
> +{
> + struct fib_rule_hdr *frh;
> +
> + if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh))) {
> + NL_SET_ERR_MSG(extack, "Invalid header");
> + return -EINVAL;
> + }
> +
> + frh = nlmsg_data(nlh);
> + if (frh->dst_len || frh->src_len || frh->tos || frh->table ||
> + frh->res1 || frh->res2 || frh->action || frh->flags) {
> + NL_SET_ERR_MSG(extack,
> + "Invalid values in header for dump request");
> + return -EINVAL;
> + }
> +
> + if (nlh->nlmsg_len != nlmsg_msg_size(sizeof(*frh))) {
> + NL_SET_ERR_MSG(extack, "Invalid data after header");
> + return -EINVAL;
> + }
> +
> + return 0;
> +}
> +
> static int fib_nl_dumprule(struct sk_buff *skb, struct netlink_callback *cb)
> {
> + const struct nlmsghdr *nlh = cb->nlh;
> struct net *net = sock_net(skb->sk);
> struct fib_rules_ops *ops;
> int idx = 0, family;
>
> - family = rtnl_msg_family(cb->nlh);
> + if (cb->strict_check) {
> + int err = fib_valid_dumprule(nlh, cb->extack);
> +
> + if (err)
> + return err;
> + }
> +
> + family = rtnl_msg_family(nlh);
> if (family != AF_UNSPEC) {
> /* Protocol specific dump request */
> ops = lookup_rules_ops(net, family);
> --
> 2.11.0
>
