Commit bb436283 authored Dec 31, 2021 by Pavel Skripkin Committed by Wolfram Sang Dec 31, 2021

i2c: validate user data in compat ioctl



Wrong user data may cause warning in i2c_transfer(), ex: zero msgs.
Userspace should not be able to trigger warnings, so this patch adds
validation checks for user data in compact ioctl to prevent reported
warnings

Reported-and-tested-by:  <syzbot+e417648b303855b91d8a@syzkaller.appspotmail.com>
Fixes: 7d5cb456 ("i2c compat ioctls: move to ->compat_ioctl()")
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

parent fc74e0a4

drivers/i2c/i2c-dev.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -535,6 +535,9 @@ static long compat_i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned lo
		sizeof(rdwr_arg)))
		return -EFAULT;

		if (!rdwr_arg.msgs \|\| rdwr_arg.nmsgs == 0)
		return -EINVAL;

		if (rdwr_arg.nmsgs > I2C_RDWR_IOCTL_MAX_MSGS)
		return -EINVAL;