[PATCH 5.9 320/757] mt76: fix a possible NULL pointer dereference in mt76_testmode_dump

Greg Kroah-Hartman
2020-10-27T15:41:44Z

From: Lorenzo Bianconi <lorenzo@kernel.org>

[ Upstream commit ce8463a726a5669b200a1c2c17f95bc1394cc6bf ]

Fix a possible NULL pointer dereference in mt76_testmode_dump() since
nla_nest_start returns NULL in case of error

Fixes: f0efa8621550e ("mt76: add API for testmode support")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/wireless/mediatek/mt76/testmode.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/testmode.c b/drivers/net/wireless/mediatek/mt76/testmode.c
index 75bb02cdfdae4..5bd6ac1ba3b5b 100644
--- a/drivers/net/wireless/mediatek/mt76/testmode.c
+++ b/drivers/net/wireless/mediatek/mt76/testmode.c
@@ -442,9 +442,13 @@ int mt76_testmode_dump(struct ieee80211_hw *hw, struct sk_buff *msg,
mutex_lock(&dev->mutex);

if (tb[MT76_TM_ATTR_STATS]) {
+ err = -EINVAL;
+
a = nla_nest_start(msg, MT76_TM_ATTR_STATS);
- err = mt76_testmode_dump_stats(dev, msg);
- nla_nest_end(msg, a);
+ if (a) {
+ err = mt76_testmode_dump_stats(dev, msg);
+ nla_nest_end(msg, a);
+ }

goto out;
}
--
2.25.1