Subject: [PATCH RFC v2 net-next 25/25] net: Enable kernel side filtering of route dumps

From: David Ahern <[email-masked]>
Date: Mon, 1 Oct 2018 17:28:51 -0700

From: David Ahern <[email-masked]>

Update parsing of route dump request to enable kernel side of filtering.

Signed-off-by: David Ahern <[email-masked]>
---
 net/ipv4/fib_frontend.c | 42 ++++++++++++++++++++++++++++++------------
 1 file changed, 30 insertions(+), 12 deletions(-)

diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index a3f4073e509a..d1ef1cb98139 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -806,7 +806,9 @@ int ip_valid_fib_dump_req(const struct nlmsghdr *nlh,
 			  struct fib_dump_filter *filter,
 			  struct netlink_ext_ack *extack)
 {
+	struct nlattr *tb[RTA_MAX + 1];
 	struct rtmsg *rtm;
+	int err, i;
 
 	if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*rtm))) {
 		NL_SET_ERR_MSG(extack, "Invalid header");
@@ -814,21 +816,37 @@ int ip_valid_fib_dump_req(const struct nlmsghdr *nlh,
 	}
 
 	rtm = nlmsg_data(nlh);
-	if (rtm->rtm_dst_len || rtm->rtm_src_len  || rtm->rtm_tos   ||
-	    rtm->rtm_table   || rtm->rtm_protocol || rtm->rtm_scope ||
-	    rtm->rtm_type) {
-		NL_SET_ERR_MSG(extack,
-			       "Invalid values in header for dump request");
+	if (rtm->rtm_dst_len || rtm->rtm_src_len) {
+		NL_SET_ERR_MSG(extack, "Invalid values in header for dump request");
 		return -EINVAL;
 	}
 
-	if (rtm->rtm_flags & ~(RTM_F_CLONED | RTM_F_PREFIX)) {
-		NL_SET_ERR_MSG(extack, "Invalid flags for dump request");
-		return -EINVAL;
-	}
-	if (nlh->nlmsg_len != nlmsg_msg_size(sizeof(*rtm))) {
-		NL_SET_ERR_MSG(extack, "Invalid data after header");
-		return -EINVAL;
+	filter->flags    = rtm->rtm_flags;
+	filter->tos      = rtm->rtm_tos;
+	filter->protocol = rtm->rtm_protocol;
+	filter->scope    = rtm->rtm_scope;
+	filter->rt_type  = rtm->rtm_type;
+	filter->table_id = rtm->rtm_table;
+
+	err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX,
+			  rtm_ipv4_policy, extack);
+	if (err < 0)
+		return err;
+
+	for (i = 0; i <= RTA_MAX; ++i) {
+		if (!tb[i])
+			continue;
+		switch (i) {
+		case RTA_TABLE:
+			filter->table_id = nla_get_u32(tb[i]);
+			break;
+		case RTA_OIF:
+			filter->ifindex = nla_get_u32(tb[i]);
+			break;
+		default:
+			NL_SET_ERR_MSG(extack, "Unsupported attribute in dump request");
+			return -EINVAL;
+		}
 	}
 
 	return 0;
-- 
2.11.0