mwifiex: fix memory corruption when unsetting multicast list

When trying to unset a previously-set multicast list (i.e. the new list
has 0 entries), mwifiex_set_multicast_list() was calling down to
mwifiex_request_set_multicast_list() while leaving
mcast_list.num_multicast_addr as an uninitialized value.

We were arriving at mwifiex_cmd_mac_multicast_adr() which would then
proceed to do an often huge memcpy of
mcast_list.num_multicast_addr*ETH_ALEN bytes, causing memory corruption
and hard to debug crashes.

Fix this by setting mcast_list.num_multicast_addr to 0 when no multicast
list is provided. Similarly, fix up the logic in
mwifiex_request_set_multicast_list() to unset the multicast list that
was previously sent to the hardware in such cases.

Signed-off-by: Daniel Drake <dsd@laptop.org>
Acked-by: Bing Zhao <bzhao@marvell.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/drivers/net/wireless/mwifiex/main.c b/drivers/net/wireless/mwifiex/main.c
index 485871940d3cbfe71e133472d29557ad0ed95073..e15ab72fb03ddc1ad6eab8e54aded37de3143253 100644 (file)
--- a/drivers/net/wireless/mwifiex/main.c
+++ b/drivers/net/wireless/mwifiex/main.c
@@ -669,9 +669,8 @@ static void mwifiex_set_multicast_list(struct net_device *dev)
                mcast_list.mode = MWIFIEX_ALL_MULTI_MODE;
        } else {
                mcast_list.mode = MWIFIEX_MULTICAST_MODE;
-               if (netdev_mc_count(dev))
-                       mcast_list.num_multicast_addr =
-                               mwifiex_copy_mcast_addr(&mcast_list, dev);
+               mcast_list.num_multicast_addr =
+                       mwifiex_copy_mcast_addr(&mcast_list, dev);
        }
        mwifiex_request_set_multicast_list(priv, &mcast_list);
 }

diff --git a/drivers/net/wireless/mwifiex/sta_ioctl.c b/drivers/net/wireless/mwifiex/sta_ioctl.c
index 1a8a19dbd635df7b6b012533605cdde724c0d000..23aa910bc5d0c1691a5bf8354881083f98ecd138 100644 (file)
--- a/drivers/net/wireless/mwifiex/sta_ioctl.c
+++ b/drivers/net/wireless/mwifiex/sta_ioctl.c
@@ -104,16 +104,14 @@ int mwifiex_request_set_multicast_list(struct mwifiex_private *priv,
                } else {
                        priv->curr_pkt_filter &=
                                ~HostCmd_ACT_MAC_ALL_MULTICAST_ENABLE;
-                       if (mcast_list->num_multicast_addr) {
-                               dev_dbg(priv->adapter->dev,
-                                       "info: Set multicast list=%d\n",
-                                      mcast_list->num_multicast_addr);
-                               /* Send multicast addresses to firmware */
-                               ret = mwifiex_send_cmd_async(priv,
-                                       HostCmd_CMD_MAC_MULTICAST_ADR,
-                                       HostCmd_ACT_GEN_SET, 0,
-                                       mcast_list);
-                       }
+                       dev_dbg(priv->adapter->dev,
+                               "info: Set multicast list=%d\n",
+                               mcast_list->num_multicast_addr);
+                       /* Send multicast addresses to firmware */
+                       ret = mwifiex_send_cmd_async(priv,
+                               HostCmd_CMD_MAC_MULTICAST_ADR,
+                               HostCmd_ACT_GEN_SET, 0,
+                               mcast_list);
                }
        }
        dev_dbg(priv->adapter->dev,