From: David Ahern <dsahern@gmail.com>
Date: Mon, 8 Oct 2018 03:16:42 +0000 (-0700)
Subject: net/bridge: Update br_mdb_dump for strict data checking
X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=c77b93641e7dc88ef4919d8126949e3ec3ffe407;p=openwrt%2Fstaging%2Fblogic.git

net/bridge: Update br_mdb_dump for strict data checking

Update br_mdb_dump for strict data checking. If the flag is set,
the dump request is expected to have a br_port_msg 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>
---

diff --git a/net/bridge/br_mdb.c b/net/bridge/br_mdb.c
index a4a848bf827b..a7ea2d431714 100644
--- a/net/bridge/br_mdb.c
+++ b/net/bridge/br_mdb.c
@@ -162,6 +162,29 @@ out:
 	return err;
 }
 
+static int br_mdb_valid_dump_req(const struct nlmsghdr *nlh,
+				 struct netlink_ext_ack *extack)
+{
+	struct br_port_msg *bpm;
+
+	if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*bpm))) {
+		NL_SET_ERR_MSG_MOD(extack, "Invalid header for mdb dump request");
+		return -EINVAL;
+	}
+
+	bpm = nlmsg_data(nlh);
+	if (bpm->ifindex) {
+		NL_SET_ERR_MSG_MOD(extack, "Filtering by device index is not supported for mdb dump request");
+		return -EINVAL;
+	}
+	if (nlmsg_attrlen(nlh, sizeof(*bpm))) {
+		NL_SET_ERR_MSG(extack, "Invalid data after header in mdb dump request");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 static int br_mdb_dump(struct sk_buff *skb, struct netlink_callback *cb)
 {
 	struct net_device *dev;
@@ -169,6 +192,13 @@ static int br_mdb_dump(struct sk_buff *skb, struct netlink_callback *cb)
 	struct nlmsghdr *nlh = NULL;
 	int idx = 0, s_idx;
 
+	if (cb->strict_check) {
+		int err = br_mdb_valid_dump_req(cb->nlh, cb->extack);
+
+		if (err < 0)
+			return err;
+	}
+
 	s_idx = cb->args[0];
 
 	rcu_read_lock();