This is a note to let you know that I've just added the patch titled
media: dvb-usb-v2: rtl28xxu: fix null-ptr-deref in rtl28xxu_i2c_xfer
to the 4.14-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-dvb-usb-v2-rtl28xxu-fix-null-ptr-deref-in-rtl2.patch
and it can be found in the queue-4.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 91716005b5ae6fea997510e38ac8dd6f0e72cb6b
Author: Zhang Shurong <zhang_shurong@xxxxxxxxxxx>
Date: Sun May 7 15:52:47 2023 +0100
media: dvb-usb-v2: rtl28xxu: fix null-ptr-deref in rtl28xxu_i2c_xfer
[ Upstream commit aa4a447b81b84f69c1a89ad899df157f386d7636 ]
In rtl28xxu_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 rtl28xxu_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()")
Link: https://lore.kernel.org/linux-media/tencent_3623572106754AC2F266B316798B0F6CCA05@xxxxxx
Signed-off-by: Zhang Shurong <zhang_shurong@xxxxxxxxxxx>
Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/media/usb/dvb-usb-v2/rtl28xxu.c b/drivers/media/usb/dvb-usb-v2/rtl28xxu.c
index bfce2d6addf7e..5c0ad2dc315a5 100644
--- a/drivers/media/usb/dvb-usb-v2/rtl28xxu.c
+++ b/drivers/media/usb/dvb-usb-v2/rtl28xxu.c
@@ -189,6 +189,10 @@ static int rtl28xxu_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msg[],
ret = -EOPNOTSUPP;
goto err_mutex_unlock;
} else if (msg[0].addr == 0x10) {
+ if (msg[0].len < 1 || msg[1].len < 1) {
+ ret = -EOPNOTSUPP;
+ goto err_mutex_unlock;
+ }
/* method 1 - integrated demod */
if (msg[0].buf[0] == 0x00) {
/* return demod page from driver cache */
@@ -202,6 +206,10 @@ static int rtl28xxu_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msg[],
ret = rtl28xxu_ctrl_msg(d, &req);
}
} else if (msg[0].len < 2) {
+ if (msg[0].len < 1) {
+ ret = -EOPNOTSUPP;
+ goto err_mutex_unlock;
+ }
/* method 2 - old I2C */
req.value = (msg[0].buf[0] << 8) | (msg[0].addr << 1);
req.index = CMD_I2C_RD;
@@ -230,8 +238,16 @@ static int rtl28xxu_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msg[],
ret = -EOPNOTSUPP;
goto err_mutex_unlock;
} else if (msg[0].addr == 0x10) {
+ if (msg[0].len < 1) {
+ ret = -EOPNOTSUPP;
+ goto err_mutex_unlock;
+ }
/* method 1 - integrated demod */
if (msg[0].buf[0] == 0x00) {
+ if (msg[0].len < 2) {
+ ret = -EOPNOTSUPP;
+ goto err_mutex_unlock;
+ }
/* save demod page for later demod access */
dev->page = msg[0].buf[1];
ret = 0;
@@ -244,6 +260,10 @@ static int rtl28xxu_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msg[],
ret = rtl28xxu_ctrl_msg(d, &req);
}
} else if ((msg[0].len < 23) && (!dev->new_i2c_write)) {
+ if (msg[0].len < 1) {
+ ret = -EOPNOTSUPP;
+ goto err_mutex_unlock;
+ }
/* method 2 - old I2C */
req.value = (msg[0].buf[0] << 8) | (msg[0].addr << 1);
req.index = CMD_I2C_WR;
