From: Pavel Skripkin paskripkin@gmail.com

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: 7d5cb45655f2 ("i2c compat ioctls: move to ->compat_ioctl()") Signed-off-by: Pavel Skripkin paskripkin@gmail.com Signed-off-by: Wolfram Sang wsa@kernel.org Signed-off-by: Hongbo Li lihongbo22@huawei.com --- drivers/i2c/i2c-dev.c | 3 +++ 1 file changed, 3 insertions(+)

diff --git a/drivers/i2c/i2c-dev.c b/drivers/i2c/i2c-dev.c index cb07651f4b46..71ed4a99c7ee 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;