Commit 63d962ac authored Jul 08, 2023 by Zhang Shurong Committed by Greg Kroah-Hartman Sep 23, 2023

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



[ 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>

parent ecbe6d01

drivers/media/usb/dvb-usb/af9005.c

+5 −0

Original line number	Diff line number	Diff line
		@@ -431,6 +431,10 @@ 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;
		@@ -440,6 +444,7 @@ static int af9005_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msg[],
		ret = 1;
		}

		unlock:
		mutex_unlock(&d->i2c_mutex);
		return ret;
		}