linux-kernel - [PATCH v1 2/2] i2c: dev: Force case user pointers in compat_i2cdev

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Date:   Mon, 11 Apr 2022 21:07:52 +0300
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Jakub Kicinski <kuba@...nel.org>, linux-i2c@...r.kernel.org,
        linux-kernel@...r.kernel.org
Cc:     Wolfram Sang <wsa@...nel.org>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Subject: [PATCH v1 2/2] i2c: dev: Force case user pointers in compat_i2cdev_ioctl()

Sparse has warned us about wrong address space for user pointers:

  i2c-dev.c:561:50: warning: incorrect type in initializer (different address spaces)
  i2c-dev.c:561:50:    expected unsigned char [usertype] *buf
  i2c-dev.c:561:50:    got void [noderef] __user *

Force cast the pointer to (__u8 *) that is used by I²C core code.

Note, this is an additional fix to the previously addressed similar issue
in the I2C_RDWR case in the same function.

Fixes: 3265a7e6b41b ("i2c: dev: Add __user annotation")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
---
 drivers/i2c/i2c-dev.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/i2c/i2c-dev.c b/drivers/i2c/i2c-dev.c
index 6fd2b6718b08..ab0adaa130da 100644
--- a/drivers/i2c/i2c-dev.c
+++ b/drivers/i2c/i2c-dev.c
@@ -557,7 +557,7 @@ static long compat_i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned lo
 				.addr = umsg.addr,
 				.flags = umsg.flags,
 				.len = umsg.len,
-				.buf = compat_ptr(umsg.buf)
+				.buf = (__force __u8 *)compat_ptr(umsg.buf),
 			};
 		}
 
-- 
2.35.1