This is a note to let you know that I've just added the patch titled i2c: validate user data in compat ioctl to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: i2c-validate-user-data-in-compat-ioctl.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 2bc44df0c237da85540fafae2c1cd328bce65946 Author: Pavel Skripkin <paskripkin@xxxxxxxxx> Date: Fri Dec 31 01:47:50 2021 +0300 i2c: validate user data in compat ioctl [ Upstream commit bb436283e25aaf1533ce061605d23a9564447bdf ] 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@xxxxxxxxxxxxxxxxxxxxxxxxx Fixes: 7d5cb45655f2 ("i2c compat ioctls: move to ->compat_ioctl()") Signed-off-by: Pavel Skripkin <paskripkin@xxxxxxxxx> Signed-off-by: Wolfram Sang <wsa@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/i2c/i2c-dev.c b/drivers/i2c/i2c-dev.c index c9ae1895cd48a..7da6ca26a5f56 100644 --- a/drivers/i2c/i2c-dev.c +++ b/drivers/i2c/i2c-dev.c @@ -536,6 +536,9 @@ 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;