[PATCH] watchdog: sbc_fitpc2_wdt: add __user annotations

[PATCH] watchdog: sbc_fitpc2_wdt: add __user annotations

[Rasmus Villemoes]

After a change to the put_user() macro on x86, kernel test robot has
started sending me complaints (from sparse) about passing kernel
pointers to put_user(). So add the __user annotations to the various
casts in fitpc2_wdt_ioctl(), and while in here, also make the write
method actually match the prototype of file_operations::write.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
---
 drivers/watchdog/sbc_fitpc2_wdt.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/watchdog/sbc_fitpc2_wdt.c b/drivers/watchdog/sbc_fitpc2_wdt.c
index 04483d6453d6a147703e..13db71e165836eb73249 100644
--- a/drivers/watchdog/sbc_fitpc2_wdt.c
+++ b/drivers/watchdog/sbc_fitpc2_wdt.c
@@ -78,7 +78,7 @@ static int fitpc2_wdt_open(struct inode *inode, struct file *file)
 	return stream_open(inode, file);
 }
 
-static ssize_t fitpc2_wdt_write(struct file *file, const char *data,
+static ssize_t fitpc2_wdt_write(struct file *file, const char __user *data,
 						size_t len, loff_t *ppos)
 {
 	size_t i;
@@ -125,16 +125,16 @@ static long fitpc2_wdt_ioctl(struct file *file, unsigned int cmd,
 
 	switch (cmd) {
 	case WDIOC_GETSUPPORT:
-		ret = copy_to_user((struct watchdog_info *)arg, &ident,
+		ret = copy_to_user((struct watchdog_info __user *)arg, &ident,
 				   sizeof(ident)) ? -EFAULT : 0;
 		break;
 
 	case WDIOC_GETSTATUS:
-		ret = put_user(0, (int *)arg);
+		ret = put_user(0, (int __user *)arg);
 		break;
 
 	case WDIOC_GETBOOTSTATUS:
-		ret = put_user(0, (int *)arg);
+		ret = put_user(0, (int __user *)arg);
 		break;
 
 	case WDIOC_KEEPALIVE:
@@ -143,7 +143,7 @@ static long fitpc2_wdt_ioctl(struct file *file, unsigned int cmd,
 		break;
 
 	case WDIOC_SETTIMEOUT:
-		ret = get_user(time, (int *)arg);
+		ret = get_user(time, (int __user *)arg);
 		if (ret)
 			break;
 
@@ -157,7 +157,7 @@ static long fitpc2_wdt_ioctl(struct file *file, unsigned int cmd,
 		fallthrough;
 
 	case WDIOC_GETTIMEOUT:
-		ret = put_user(margin, (int *)arg);
+		ret = put_user(margin, (int __user *)arg);
 		break;
 	}
 
-- 
2.23.0

Re: [PATCH] watchdog: sbc_fitpc2_wdt: add __user annotations

[Guenter Roeck]

On 10/25/20 5:45 AM, Rasmus Villemoes wrote:
> After a change to the put_user() macro on x86, kernel test robot has
> started sending me complaints (from sparse) about passing kernel
> pointers to put_user(). So add the __user annotations to the various
> casts in fitpc2_wdt_ioctl(), and while in here, also make the write
> method actually match the prototype of file_operations::write.
> 
> Reported-by: kernel test robot <lkp@intel.com>
> Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>

It would really be great if we can get rid of all those old drivers.
Can we mark them all as deprecated ?

Reviewed-by: Guenter Roeck <inux@roeck-us.net>

> ---
>  drivers/watchdog/sbc_fitpc2_wdt.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/watchdog/sbc_fitpc2_wdt.c b/drivers/watchdog/sbc_fitpc2_wdt.c
> index 04483d6453d6a147703e..13db71e165836eb73249 100644
> --- a/drivers/watchdog/sbc_fitpc2_wdt.c
> +++ b/drivers/watchdog/sbc_fitpc2_wdt.c
> @@ -78,7 +78,7 @@ static int fitpc2_wdt_open(struct inode *inode, struct file *file)
>  	return stream_open(inode, file);
>  }
>  
> -static ssize_t fitpc2_wdt_write(struct file *file, const char *data,
> +static ssize_t fitpc2_wdt_write(struct file *file, const char __user *data,
>  						size_t len, loff_t *ppos)
>  {
>  	size_t i;
> @@ -125,16 +125,16 @@ static long fitpc2_wdt_ioctl(struct file *file, unsigned int cmd,
>  
>  	switch (cmd) {
>  	case WDIOC_GETSUPPORT:
> -		ret = copy_to_user((struct watchdog_info *)arg, &ident,
> +		ret = copy_to_user((struct watchdog_info __user *)arg, &ident,
>  				   sizeof(ident)) ? -EFAULT : 0;
>  		break;
>  
>  	case WDIOC_GETSTATUS:
> -		ret = put_user(0, (int *)arg);
> +		ret = put_user(0, (int __user *)arg);
>  		break;
>  
>  	case WDIOC_GETBOOTSTATUS:
> -		ret = put_user(0, (int *)arg);
> +		ret = put_user(0, (int __user *)arg);
>  		break;
>  
>  	case WDIOC_KEEPALIVE:
> @@ -143,7 +143,7 @@ static long fitpc2_wdt_ioctl(struct file *file, unsigned int cmd,
>  		break;
>  
>  	case WDIOC_SETTIMEOUT:
> -		ret = get_user(time, (int *)arg);
> +		ret = get_user(time, (int __user *)arg);
>  		if (ret)
>  			break;
>  
> @@ -157,7 +157,7 @@ static long fitpc2_wdt_ioctl(struct file *file, unsigned int cmd,
>  		fallthrough;
>  
>  	case WDIOC_GETTIMEOUT:
> -		ret = put_user(margin, (int *)arg);
> +		ret = put_user(margin, (int __user *)arg);
>  		break;
>  	}
>  
>