From: Wei Chen <harperchen1110@gmail.com>
To: mchehab@kernel.org
Cc: linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
Wei Chen <harperchen1110@gmail.com>
Subject: [PATCH] media: dvb-usb: digitv: Fix null-ptr-deref in digitv_i2c_xfer()
Date: Mon, 13 Mar 2023 09:50:08 +0000 [thread overview]
Message-ID: <20230313095008.1039689-1-harperchen1110@gmail.com> (raw)
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()")
Signed-off-by: Wei Chen <harperchen1110@gmail.com>
---
drivers/media/usb/dvb-usb/digitv.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/media/usb/dvb-usb/digitv.c b/drivers/media/usb/dvb-usb/digitv.c
index 2756815a780b..32134be16914 100644
--- a/drivers/media/usb/dvb-usb/digitv.c
+++ b/drivers/media/usb/dvb-usb/digitv.c
@@ -63,6 +63,10 @@ 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,
--
2.25.1
reply other threads:[~2023-03-13 9:50 UTC|newest]
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