This is a note to let you know that I've just added the patch titled
media: dw2102: Fix null-ptr-deref in dw2102_i2c_transfer()
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
media-dw2102-fix-null-ptr-deref-in-dw2102_i2c_transf.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit e7c263a213253dfe914f77c0ca309766f2cd046d
Author: Zhang Shurong <zhang_shurong@xxxxxxxxxxx>
Date: Sat Jul 8 18:22:52 2023 +0800
media: dw2102: Fix null-ptr-deref in dw2102_i2c_transfer()
[ Upstream commit 5ae544d94abc8ff77b1b9bf8774def3fa5689b5b ]
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>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/media/usb/dvb-usb/dw2102.c b/drivers/media/usb/dvb-usb/dw2102.c
index cd0566c0b3de7..a3c5261f9aa41 100644
--- a/drivers/media/usb/dvb-usb/dw2102.c
+++ b/drivers/media/usb/dvb-usb/dw2102.c
@@ -131,6 +131,10 @@ 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++) {
@@ -142,6 +146,10 @@ 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];
@@ -151,6 +159,10 @@ 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;
@@ -162,6 +174,10 @@ 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);
@@ -169,12 +185,20 @@ 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,
