From: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Date: Mon, 5 Jun 2017 22:26:24 +0000 (+0300)
Subject: net: bridge: fix a null pointer dereference in br_afspec
X-Git-Tag: v4.12-rc5~33^2~3
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=1020ce3108cc26fbf09d70550ea2937cb1a211d2;p=linux.git

net: bridge: fix a null pointer dereference in br_afspec

We might call br_afspec() with p == NULL which is a valid use case if
the action is on the bridge device itself, but the bridge tunnel code
dereferences the p pointer without checking, so check if p is null
first.

Reported-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Fixes: efa5356b0d97 ("bridge: per vlan dst_metadata netlink support")
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Acked-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
index 574f78824d8a..32bd3ead9ba1 100644
--- a/net/bridge/br_netlink.c
+++ b/net/bridge/br_netlink.c
@@ -595,7 +595,7 @@ static int br_afspec(struct net_bridge *br,
 		err = 0;
 		switch (nla_type(attr)) {
 		case IFLA_BRIDGE_VLAN_TUNNEL_INFO:
-			if (!(p->flags & BR_VLAN_TUNNEL))
+			if (!p || !(p->flags & BR_VLAN_TUNNEL))
 				return -EINVAL;
 			err = br_parse_vlan_tunnel_info(attr, &tinfo_curr);
 			if (err)