[PATCH AUTOSEL 4.19 044/219] mwifiex: fix potential NULL dereference and use after free

Sasha Levin
2019-11-22T05:50:09Z

From: Pan Bian <bianpan2016@163.com>

[ Upstream commit 1dcd9429212b98bea87fc6ec92fb50bf5953eb47 ]

There are two defects: (1) passing a NULL bss to
mwifiex_save_hidden_ssid_channels will result in NULL dereference,
(2) using bss after dropping the reference to it via cfg80211_put_bss.
To fix them, the patch moves the buggy code to the branch that bss is
not NULL and puts it before cfg80211_put_bss.

Signed-off-by: Pan Bian <bianpan2016@163.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/wireless/marvell/mwifiex/scan.c | 18 ++++++++++--------
1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/drivers/net/wireless/marvell/mwifiex/scan.c b/drivers/net/wireless/marvell/mwifiex/scan.c
index ed27147efcb37..dd02bbd9544e7 100644
--- a/drivers/net/wireless/marvell/mwifiex/scan.c
+++ b/drivers/net/wireless/marvell/mwifiex/scan.c
@@ -1906,15 +1906,17 @@ mwifiex_parse_single_response_buf(struct mwifiex_private *priv, u8 **bss_info,
ETH_ALEN))
mwifiex_update_curr_bss_params(priv,
bss);
- cfg80211_put_bss(priv->wdev.wiphy, bss);
- }

- if ((chan->flags & IEEE80211_CHAN_RADAR) ||
- (chan->flags & IEEE80211_CHAN_NO_IR)) {
- mwifiex_dbg(adapter, INFO,
- "radar or passive channel %d\n",
- channel);
- mwifiex_save_hidden_ssid_channels(priv, bss);
+ if ((chan->flags & IEEE80211_CHAN_RADAR) ||
+ (chan->flags & IEEE80211_CHAN_NO_IR)) {
+ mwifiex_dbg(adapter, INFO,
+ "radar or passive channel %d\n",
+ channel);
+ mwifiex_save_hidden_ssid_channels(priv,
+ bss);
+ }
+
+ cfg80211_put_bss(priv->wdev.wiphy, bss);
}
}
} else {
--
2.20.1