This is a note to let you know that I've just added the patch titled
media: dvb-usb: digitv: fix null-ptr-deref in digitv_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-digitv-fix-null-ptr-deref-in-digitv_i2.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 45ed9cc9b484d2a24ab14f00e8debc581c4f34af
Author: Wei Chen <harperchen1110@xxxxxxxxx>
Date: Mon Mar 13 09:50:08 2023 +0000
media: dvb-usb: digitv: fix null-ptr-deref in digitv_i2c_xfer()
[ Upstream commit 9ded5bd2a49ce3015b7c936743eec0a0e6e11f0c ]
In digitv_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 digitv_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/20230313095008.1039689-1-harperchen1110@xxxxxxxxx
Signed-off-by: Wei Chen <harperchen1110@xxxxxxxxx>
Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/media/usb/dvb-usb/digitv.c b/drivers/media/usb/dvb-usb/digitv.c
index 20d33f0544ed2..0e2cffa946f69 100644
--- a/drivers/media/usb/dvb-usb/digitv.c
+++ b/drivers/media/usb/dvb-usb/digitv.c
@@ -66,6 +66,10 @@ static int digitv_i2c_xfer(struct i2c_adapter *adap,struct i2c_msg msg[],int num
warn("more than 2 i2c messages at a time is not handled yet. TODO.");
for (i = 0; i < num; i++) {
+ if (msg[i].len < 1) {
+ i = -EOPNOTSUPP;
+ break;
+ }
/* write/read request */
if (i+1 < num && (msg[i+1].flags & I2C_M_RD)) {
if (digitv_ctrl_msg(d, USB_READ_COFDM, msg[i].buf[0], NULL, 0,
