linux-kernel - [PATCH] media: dvb-usb-v2: af9035: Fix null-ptr-deref in af9035_i2c_master

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-ID: <tencent_F09F5B5160131E350A90A8E5124E3709B508@qq.com>
Date:   Thu,  6 Jul 2023 00:06:54 +0800
From:   Zhang Shurong <zhang_shurong@...mail.com>
To:     crope@....fi
Cc:     mchehab@...nel.org, linux-media@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Zhang Shurong <zhang_shurong@...mail.com>
Subject: [PATCH] media: dvb-usb-v2: af9035: Fix null-ptr-deref in af9035_i2c_master_xfer

In af9035_i2c_master_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 af9035_i2c_master_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: Zhang Shurong <zhang_shurong@...mail.com>
---
 drivers/media/usb/dvb-usb-v2/af9035.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/media/usb/dvb-usb-v2/af9035.c b/drivers/media/usb/dvb-usb-v2/af9035.c
index 1e9c8d01523b..33a2aa8907e6 100644
--- a/drivers/media/usb/dvb-usb-v2/af9035.c
+++ b/drivers/media/usb/dvb-usb-v2/af9035.c
@@ -322,6 +322,8 @@ static int af9035_i2c_master_xfer(struct i2c_adapter *adap,
 			ret = -EOPNOTSUPP;
 		} else if ((msg[0].addr == state->af9033_i2c_addr[0]) ||
 			   (msg[0].addr == state->af9033_i2c_addr[1])) {
+			if (msg[0].len < 3 || msg[1].len < 1)
+				return -EOPNOTSUPP;
 			/* demod access via firmware interface */
 			u32 reg = msg[0].buf[0] << 16 | msg[0].buf[1] << 8 |
 					msg[0].buf[2];
@@ -381,6 +383,8 @@ static int af9035_i2c_master_xfer(struct i2c_adapter *adap,
 			ret = -EOPNOTSUPP;
 		} else if ((msg[0].addr == state->af9033_i2c_addr[0]) ||
 			   (msg[0].addr == state->af9033_i2c_addr[1])) {
+			if (msg[0].len < 3)
+				return -EOPNOTSUPP;
 			/* demod access via firmware interface */
 			u32 reg = msg[0].buf[0] << 16 | msg[0].buf[1] << 8 |
 					msg[0].buf[2];
@@ -388,10 +392,7 @@ static int af9035_i2c_master_xfer(struct i2c_adapter *adap,
 			if (msg[0].addr == state->af9033_i2c_addr[1])
 				reg |= 0x100000;
 
-			ret = (msg[0].len >= 3) ? af9035_wr_regs(d, reg,
-							         &msg[0].buf[3],
-							         msg[0].len - 3)
-					        : -EOPNOTSUPP;
+			ret = af9035_wr_regs(d, reg, &msg[0].buf[3], msg[0].len - 3);
 		} else {
 			/* I2C write */
 			u8 buf[MAX_XFER_SIZE];
-- 
2.30.2