From 4a73e5e56d667e354926fe3f5f1aa75ff18bca51 Mon Sep 17 00:00:00 2001 From: David Ahern Date: Sun, 7 Oct 2018 20:16:39 -0700 Subject: [PATCH] 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 Acked-by: Christian Brauner Signed-off-by: David S. Miller --- 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..ffbb827723a2 100644 --- a/net/core/fib_rules.c +++ b/net/core/fib_rules.c @@ -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); -- 2.30.2