IPoIB: Check multicast address format

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

Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

1 files changed, 19 insertions, 0 deletions

diff --git a/drivers/infiniband/ulp/ipoib/ipoib_multicast.c b/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
index a0825fe451e0..25874fc680c9 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
@@ -760,6 +760,20 @@ void ipoib_mcast_dev_flush(struct net_device *dev)
         }
 }
 
+static int ipoib_mcast_addr_is_valid(const u8 *addr, unsigned int addrlen,
+                                     const u8 *broadcast)
+{
+        if (addrlen != INFINIBAND_ALEN)
+                return 0;
+        /* reserved QPN, prefix, scope */
+        if (memcmp(addr, broadcast, 6))
+                return 0;
+        /* signature lower, pkey */
+        if (memcmp(addr + 7, broadcast + 7, 3))
+                return 0;
+        return 1;
+}
+
 void ipoib_mcast_restart_task(struct work_struct *work)
 {
         struct ipoib_dev_priv *priv =
@@ -793,6 +807,11 @@ void ipoib_mcast_restart_task(struct work_struct *work)
         for (mclist = dev->mc_list; mclist; mclist = mclist->next) {
                 union ib_gid mgid;
 
+                if (!ipoib_mcast_addr_is_valid(mclist->dmi_addr,
+                                               mclist->dmi_addrlen,
+                                               dev->broadcast))
+                        continue;
+
                 memcpy(mgid.raw, mclist->dmi_addr + 4, sizeof mgid);
 
                 mcast = __ipoib_mcast_find(dev, &mgid);