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Commit adcb73f8 authored by Zhang Shurong's avatar Zhang Shurong Committed by Greg Kroah-Hartman
Browse files

media: az6007: Fix null-ptr-deref in az6007_i2c_xfer() 



[ Upstream commit 1047f9343011f2cedc73c64829686206a7e9fc3f ]

In az6007_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 az6007_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: default avatarZhang Shurong <zhang_shurong@foxmail.com>
Signed-off-by: default avatarHans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent e04affec

drivers/media/usb/dvb-usb-v2/az6007.c

+8 −0
Original line number Diff line number Diff line
@@ -796,6 +796,10 @@ static int az6007_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], 
			if (az6007_xfer_debug)

				printk(KERN_DEBUG "az6007: I2C W addr=0x%x len=%d\n",

				       addr, msgs[i].len);

			if (msgs[i].len < 1) {

				ret = -EIO;

				goto err;

			}

			req = AZ6007_I2C_WR;

			index = msgs[i].buf[0];

			value = addr | (1 << 8);
@@ -810,6 +814,10 @@ static int az6007_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], 
			if (az6007_xfer_debug)

				printk(KERN_DEBUG "az6007: I2C R addr=0x%x len=%d\n",

				       addr, msgs[i].len);

			if (msgs[i].len < 1) {

				ret = -EIO;

				goto err;

			}

			req = AZ6007_I2C_RD;

			index = msgs[i].buf[0];

			value = addr;