[PATCH 095/100] mwifiex: fix memory corruption when unsetting multicast list

From: Luis Henriques
Date: Fri Oct 11 2013 - 06:44:32 EST


3.5.7.23 -stable review patch. If anyone has any objections, please let me know.

------------------

From: Daniel Drake <dsd@xxxxxxxxxx>

commit 6390d88529835a8ad3563fe01a5da89fa52d6db2 upstream.

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@xxxxxxxxxx>
Acked-by: Bing Zhao <bzhao@xxxxxxxxxxx>
Signed-off-by: John W. Linville <linville@xxxxxxxxxxxxx>
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
---
drivers/net/wireless/mwifiex/main.c | 5 ++---
drivers/net/wireless/mwifiex/sta_ioctl.c | 18 ++++++++----------
2 files changed, 10 insertions(+), 13 deletions(-)

diff --git a/drivers/net/wireless/mwifiex/main.c b/drivers/net/wireless/mwifiex/main.c
index 4be4d43..20e50e5 100644
--- a/drivers/net/wireless/mwifiex/main.c
+++ b/drivers/net/wireless/mwifiex/main.c
@@ -571,9 +571,8 @@ 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 fc6ae9b..2ea3a20 100644
--- a/drivers/net/wireless/mwifiex/sta_ioctl.c
+++ b/drivers/net/wireless/mwifiex/sta_ioctl.c
@@ -113,16 +113,14 @@ 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,
--
1.8.3.2

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