bridge: Sanitize IFLA_EXT_MASK for AF_BRIDGE:RTM_GETLINK
Only search for IFLA_EXT_MASK if the message actually carries a
ifinfomsg header and validate minimal length requirements for
IFLA_EXT_MASK.
Fixes: 6cbdceeb ("bridge: Dump vlan information from a bridge port")
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 5a853f8..b9b7dfa 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -2685,13 +2685,20 @@
int idx = 0;
u32 portid = NETLINK_CB(cb->skb).portid;
u32 seq = cb->nlh->nlmsg_seq;
- struct nlattr *extfilt;
u32 filter_mask = 0;
- extfilt = nlmsg_find_attr(cb->nlh, sizeof(struct ifinfomsg),
- IFLA_EXT_MASK);
- if (extfilt)
- filter_mask = nla_get_u32(extfilt);
+ if (nlmsg_len(cb->nlh) > sizeof(struct ifinfomsg)) {
+ struct nlattr *extfilt;
+
+ extfilt = nlmsg_find_attr(cb->nlh, sizeof(struct ifinfomsg),
+ IFLA_EXT_MASK);
+ if (extfilt) {
+ if (nla_len(extfilt) < sizeof(filter_mask))
+ return -EINVAL;
+
+ filter_mask = nla_get_u32(extfilt);
+ }
+ }
rcu_read_lock();
for_each_netdev_rcu(net, dev) {
