2013-06-14 19:29:11

by Daniel Drake

Subject: [PATCH] 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 <[email protected]>
---
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 2eb88ea..4f5c37a 100644
--- a/drivers/net/wireless/mwifiex/main.c
+++ b/drivers/net/wireless/mwifiex/main.c
@@ -573,9 +573,8 @@ 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 1a8a19d..23aa910 100644
--- 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,
--
1.8.1.4

2013-06-15 04:07:39

by Bing Zhao

Subject: RE: [PATCH] mwifiex: fix memory corruption when unsetting multicast list

Hi Daniel,

Thanks for the patch.

> 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 <[email protected]>

Acked-by: Bing Zhao <[email protected]>

Thanks,
Bing

> ---
> drivers/net/wireless/mwifiex/main.c | 5 ++---
> drivers/net/wireless/mwifiex/sta_ioctl.c | 18 ++++++++----------
> 2 files changed, 10 insertions(+), 13 deletions(-)