media: af9005: Fix null-ptr-deref in af9005_i2c_xfer

[ Upstream commit f4ee84f276 ]

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 0ed554fd76
("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>
This commit is contained in:
Zhang Shurong 2023-07-08 23:24:11 +08:00 committed by Greg Kroah-Hartman
parent fb28afab11
commit e595ff350b

View file

@ -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;
}