In dw2102_i2c_transfer, 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 dw2102_i2c_transfer. 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 950e252cb469
("[media] dw2102: limit messages to buffer size")
Signed-off-by: Zhang Shurong <zhang_shurong@xxxxxxxxxxx>
---
drivers/media/usb/dvb-usb/dw2102.c | 24 ++++++++++++++++++++++++
1 file changed, 24 insertions(+)
diff --git a/drivers/media/usb/dvb-usb/dw2102.c b/drivers/media/usb/dvb-usb/dw2102.c
index 970b84c3f0b5..b3bb1805829a 100644
--- a/drivers/media/usb/dvb-usb/dw2102.c
+++ b/drivers/media/usb/dvb-usb/dw2102.c
@@ -128,6 +128,10 @@ static int dw2102_i2c_transfer(struct i2c_adapter *adap, struct i2c_msg msg[],
switch (num) {
case 2:
+ if (msg[0].len < 1) {
+ num = -EOPNOTSUPP;
+ break;
+ }
/* read stv0299 register */
value = msg[0].buf[0];/* register */
for (i = 0; i < msg[1].len; i++) {
@@ -139,6 +143,10 @@ static int dw2102_i2c_transfer(struct i2c_adapter *adap, struct i2c_msg msg[],
case 1:
switch (msg[0].addr) {
case 0x68:
+ if (msg[0].len < 2) {
+ num = -EOPNOTSUPP;
+ break;
+ }
/* write to stv0299 register */
buf6[0] = 0x2a;
buf6[1] = msg[0].buf[0];
@@ -148,6 +156,10 @@ static int dw2102_i2c_transfer(struct i2c_adapter *adap, struct i2c_msg msg[],
break;
case 0x60:
if (msg[0].flags == 0) {
+ if (msg[0].len < 4) {
+ num = -EOPNOTSUPP;
+ break;
+ }
/* write to tuner pll */
buf6[0] = 0x2c;
buf6[1] = 5;
@@ -159,6 +171,10 @@ static int dw2102_i2c_transfer(struct i2c_adapter *adap, struct i2c_msg msg[],
dw210x_op_rw(d->udev, 0xb2, 0, 0,
buf6, 7, DW210X_WRITE_MSG);
} else {
+ if (msg[0].len < 1) {
+ num = -EOPNOTSUPP;
+ break;
+ }
/* read from tuner */
dw210x_op_rw(d->udev, 0xb5, 0, 0,
buf6, 1, DW210X_READ_MSG);
@@ -166,12 +182,20 @@ static int dw2102_i2c_transfer(struct i2c_adapter *adap, struct i2c_msg msg[],
}
break;
case (DW2102_RC_QUERY):
+ if (msg[0].len < 2) {
+ num = -EOPNOTSUPP;
+ break;
+ }
dw210x_op_rw(d->udev, 0xb8, 0, 0,
buf6, 2, DW210X_READ_MSG);
msg[0].buf[0] = buf6[0];
msg[0].buf[1] = buf6[1];
break;
case (DW2102_VOLTAGE_CTRL):
+ if (msg[0].len < 1) {
+ num = -EOPNOTSUPP;
+ break;
+ }
buf6[0] = 0x30;
buf6[1] = msg[0].buf[0];
dw210x_op_rw(d->udev, 0xb2, 0, 0,
--
2.30.2
