Commit dff91909 authored Mar 13, 2023 by Wei Chen Committed by Mauro Carvalho Chehab May 14, 2023

media: dvb-usb-v2: ce6230: fix null-ptr-deref in ce6230_i2c_master_xfer()

In ce6230_i2c_master_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 ce6230_i2c_master_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 0ed554fd ("media: dvb-usb: az6027: fix null-ptr-deref in az6027_i2c_xfer()")

Link: https://lore.kernel.org/linux-media/20230313092751.209496-1-harperchen1110@gmail.com

Signed-off-by: Wei Chen <harperchen1110@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

parent a6dcefcc

drivers/media/usb/dvb-usb-v2/ce6230.c

+8 −0

Original line number	Diff line number	Diff line
		@@ -101,6 +101,10 @@ static int ce6230_i2c_master_xfer(struct i2c_adapter *adap,
		if (num > i + 1 && (msg[i+1].flags & I2C_M_RD)) {
		if (msg[i].addr ==
		ce6230_zl10353_config.demod_address) {
		if (msg[i].len < 1) {
		i = -EOPNOTSUPP;
		break;
		}
		req.cmd = DEMOD_READ;
		req.value = msg[i].addr >> 1;
		req.index = msg[i].buf[0];
		@@ -117,6 +121,10 @@ static int ce6230_i2c_master_xfer(struct i2c_adapter *adap,
		} else {
		if (msg[i].addr ==
		ce6230_zl10353_config.demod_address) {
		if (msg[i].len < 1) {
		i = -EOPNOTSUPP;
		break;
		}
		req.cmd = DEMOD_WRITE;
		req.value = msg[i].addr >> 1;
		req.index = msg[i].buf[0];