From 9614b623756b6428490cf4a78addb71b58dcb539 Mon Sep 17 00:00:00 2001 From: Wolfram Sang Date: Fri, 12 Mar 2021 10:29:46 +0100 Subject: [PATCH] i2c: bail out early when RDWR parameters are wrong The buggy parameters currently get caught later, but emit a noisy WARN. Userspace should not be able to trigger this, so add similar checks much earlier. Also avoids some unneeded code paths, of course. Apply kernel coding stlye to a comment while here. Reported-by: syzbot+ffb0b3ffa6cfbc7d7b3f@syzkaller.appspotmail.com Signed-off-by: Wolfram Sang --- drivers/i2c/i2c-dev.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/drivers/i2c/i2c-dev.c b/drivers/i2c/i2c-dev.c index 6ceb11cc4be1..6ef38a8ee95c 100644 --- a/drivers/i2c/i2c-dev.c +++ b/drivers/i2c/i2c-dev.c @@ -440,8 +440,13 @@ static long i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) sizeof(rdwr_arg))) return -EFAULT; - /* Put an arbitrary limit on the number of messages that can - * be sent at once */ + if (!rdwr_arg.msgs || rdwr_arg.nmsgs == 0) + return -EINVAL; + + /* + * Put an arbitrary limit on the number of messages that can + * be sent at once + */ if (rdwr_arg.nmsgs > I2C_RDWR_IOCTL_MAX_MSGS) return -EINVAL; -- 2.30.0