From: Zhang Shurong zhang_shurong@foxmail.com
[ Upstream commit f4ee84f27625ce1fdf41e8483fa0561a1b837d10 ]
In af9005_i2c_xfer, msg is controlled by user. When msg[i].buf is null and msg[i].len is zero, former checks on msg[i].buf would be passed. Malicious data finally reach af9005_i2c_xfer. If accessing msg[i].buf[0] without sanity check, null ptr deref would happen. We add check on msg[i].len to prevent crash.
Similar commit: commit 0ed554fd769a ("media: dvb-usb: az6027: fix null-ptr-deref in az6027_i2c_xfer()")
Signed-off-by: Zhang Shurong zhang_shurong@foxmail.com Signed-off-by: Hans Verkuil hverkuil-cisco@xs4all.nl Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/media/usb/dvb-usb/af9005.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/drivers/media/usb/dvb-usb/af9005.c b/drivers/media/usb/dvb-usb/af9005.c index b6a2436d16e97..9af54fcbed1de 100644 --- a/drivers/media/usb/dvb-usb/af9005.c +++ b/drivers/media/usb/dvb-usb/af9005.c @@ -422,6 +422,10 @@ static int af9005_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msg[], if (ret == 0) ret = 2; } else { + if (msg[0].len < 2) { + ret = -EOPNOTSUPP; + goto unlock; + } /* write one or more registers */ reg = msg[0].buf[0]; addr = msg[0].addr; @@ -431,6 +435,7 @@ static int af9005_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msg[], ret = 1; }
+unlock: mutex_unlock(&d->i2c_mutex); return ret; }