From: Thomas Graf <tgraf@suug.ch>
Date: Wed, 26 Nov 2014 12:42:16 +0000 (+0100)
Subject: bridge: Validate IFLA_BRIDGE_FLAGS attribute length
X-Git-Tag: firefly_0821_release~176^2~2819^2~2^2~4
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=6e8d1c55454574a22b3e8e263b1a12888909b033;p=firefly-linux-kernel-4.4.55.git

bridge: Validate IFLA_BRIDGE_FLAGS attribute length

Payload is currently accessed blindly and may exceed valid message
boundaries.

Fixes: 407af3299 ("bridge: Add netlink interface to configure vlans on bridge ports")
Cc: Vlad Yasevich <vyasevic@redhat.com>
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index a6882686ca3a..5a853f8fad6c 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -2798,6 +2798,9 @@ static int rtnl_bridge_setlink(struct sk_buff *skb, struct nlmsghdr *nlh)
 	if (br_spec) {
 		nla_for_each_nested(attr, br_spec, rem) {
 			if (nla_type(attr) == IFLA_BRIDGE_FLAGS) {
+				if (nla_len(attr) < sizeof(flags))
+					return -EINVAL;
+
 				have_flags = true;
 				flags = nla_get_u16(attr);
 				break;
@@ -2868,6 +2871,9 @@ static int rtnl_bridge_dellink(struct sk_buff *skb, struct nlmsghdr *nlh)
 	if (br_spec) {
 		nla_for_each_nested(attr, br_spec, rem) {
 			if (nla_type(attr) == IFLA_BRIDGE_FLAGS) {
+				if (nla_len(attr) < sizeof(flags))
+					return -EINVAL;
+
 				have_flags = true;
 				flags = nla_get_u16(attr);
 				break;