From: Stephen Hemminger <shemminger@vyatta.com>
Date: Fri, 6 Nov 2009 04:46:52 +0000 (-0800)
Subject: bridge: prevent bridging wrong device
X-Git-Tag: firefly_0821_release~11864^2~58
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=1056bd51674e529813213186471bb4ac6689a755;p=firefly-linux-kernel-4.4.55.git

bridge: prevent bridging wrong device

The bridge code assumes ethernet addressing, so be more strict in
the what is allowed. This showed up when GRE had a bug and was not
using correct address format.

Add some more comments for increased clarity.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c
index b1b3b0fbf41c..4a9f52732655 100644
--- a/net/bridge/br_if.c
+++ b/net/bridge/br_if.c
@@ -377,12 +377,16 @@ int br_add_if(struct net_bridge *br, struct net_device *dev)
 	struct net_bridge_port *p;
 	int err = 0;
 
-	if (dev->flags & IFF_LOOPBACK || dev->type != ARPHRD_ETHER)
+	/* Don't allow bridging non-ethernet like devices */
+	if ((dev->flags & IFF_LOOPBACK) ||
+	    dev->type != ARPHRD_ETHER || dev->addr_len != ETH_ALEN)
 		return -EINVAL;
 
+	/* No bridging of bridges */
 	if (dev->netdev_ops->ndo_start_xmit == br_dev_xmit)
 		return -ELOOP;
 
+	/* Device is already being bridged */
 	if (dev->br_port != NULL)
 		return -EBUSY;