From 71581562ee36032d2d574a9b23ad4af6d6a64cf7 Mon Sep 17 00:00:00 2001
From: Wolfram Sang <wsa+renesas@sang-engineering.com>
Date: Fri, 12 Mar 2021 12:57:34 +0100
Subject: [PATCH] i2c: bail out early when RDWR parameters are wrong
Git-commit: 71581562ee36032d2d574a9b23ad4af6d6a64cf7
Patch-mainline: v5.13-rc1
References: git-fixes
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
Tested-by: syzbot+ffb0b3ffa6cfbc7d7b3f@syzkaller.appspotmail.com
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
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;
--
2.26.2