From b97719a66970601cd3151a3e2020f4454a1c4ff6 Mon Sep 17 00:00:00 2001
From: Zhang Shurong <zhang_shurong@foxmail.com>
Date: Mon, 10 Jul 2023 13:32:13 +0800
Subject: [PATCH] media: dvb-usb-v2: gl861: Fix null-ptr-deref in gl861_i2c_master_xfer
Git-commit: b97719a66970601cd3151a3e2020f4454a1c4ff6
Patch-mainline: v6.6-rc1
References: git-fixes
In gl861_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 gl861_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@foxmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/media/usb/dvb-usb-v2/gl861.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/media/usb/dvb-usb-v2/gl861.c b/drivers/media/usb/dvb-usb-v2/gl861.c
index 0c434259c36f..c71e7b93476d 100644
--- a/drivers/media/usb/dvb-usb-v2/gl861.c
+++ b/drivers/media/usb/dvb-usb-v2/gl861.c
@@ -120,7 +120,7 @@ static int gl861_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg msg[],
} else if (num == 2 && !(msg[0].flags & I2C_M_RD) &&
(msg[1].flags & I2C_M_RD)) {
/* I2C write + read */
- if (msg[0].len > 1 || msg[1].len > sizeof(ctx->buf)) {
+ if (msg[0].len != 1 || msg[1].len > sizeof(ctx->buf)) {
ret = -EOPNOTSUPP;
goto err;
}
--
2.35.3