[ofa-general] [PATCH] IPoIB: check multicast address format

[Jason Gunthorpe]

Check that the format of the multicast link address is correct before
taking it from dev->mc_list to priv->multicast_list. This way we never
try to send a bogus address to the SA, and prevents badness from
erronous 'ip maddr addr add', broken bonding drivers, or whatever.

Signed-off-by: Jason Gunthorpe <jgunthorpe at obsidianresearch.com>
---
 drivers/infiniband/ulp/ipoib/ipoib_multicast.c |   18 ++++++++++++++++++
 1 files changed, 18 insertions(+), 0 deletions(-)

Same problem Moni was working on, but lets just address it directly.

There is work to try and fix the bonding driver but no fixed version
is in mainline yet. This is a cheap and simple work around that is
worth having even once the driver is fixed.

Despite this, I think it is still necessary to do something like Moni
was trying - to prevent the MCG join queue from head of line blocking
on a single bad SA response. This can happen even if everything is
correct.

diff --git a/drivers/infiniband/ulp/ipoib/ipoib_multicast.c b/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
index 425e311..973a24b 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
@@ -758,6 +758,20 @@ void ipoib_mcast_dev_flush(struct net_device *dev)
 	}
 }
 
+static int check_mcast(const u8 *addr,unsigned int addrlen,
+		       const u8 *broadcast)
+{
+	if (addrlen != 20)
+		return 0;
+	/* QPN, scope, reserved, sigature upper */
+	if (memcmp(addr,broadcast,6) != 0)
+		return 0;
+	/* signature lower, pkey */
+	if (memcmp(addr + 7,broadcast+7,3) != 0)
+		return 0;
+	return 1;
+}
+
 void ipoib_mcast_restart_task(struct work_struct *work)
 {
 	struct ipoib_dev_priv *priv =
@@ -791,6 +805,10 @@ void ipoib_mcast_restart_task(struct work_struct *work)
 	for (mclist = dev->mc_list; mclist; mclist = mclist->next) {
 		union ib_gid mgid;
 
+		if (!check_mcast(mclist->dmi_addr,mclist->dmi_addrlen,
+				 dev->broadcast))
+			continue;
+
 		memcpy(mgid.raw, mclist->dmi_addr + 4, sizeof mgid);
 
 		mcast = __ipoib_mcast_find(dev, &mgid);
-- 
1.5.4.2