net/fib_rules: Update fib_nl_dumprule for strict data checking

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 <dsahern@gmail.com>
Acked-by: Christian Brauner <christian@brauner.io>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David Ahern 2018-10-07 20:16:39 -07:00 committed by David S. Miller
parent f80f14c364
commit 4a73e5e56d

View File

@ -1063,13 +1063,47 @@ skip:
return err;
}
static int fib_valid_dumprule_req(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 for fib rule dump request");
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 fib rule dump request");
return -EINVAL;
}
if (nlmsg_attrlen(nlh, sizeof(*frh))) {
NL_SET_ERR_MSG(extack, "Invalid data after header in fib rule dump request");
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_req(nlh, cb->extack);
if (err < 0)
return err;
}
family = rtnl_msg_family(nlh);
if (family != AF_UNSPEC) {
/* Protocol specific dump request */
ops = lookup_rules_ops(net, family);