[PATCH] mtd: unlock on error in ioctl

[PATCH] mtd: unlock on error in ioctl

[Dan Carpenter]

We need to unlock before returning on this error path.

Fixes: 210bec567936 ("mtd: properly check all write ioctls for permissions")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
 drivers/mtd/mtdchar.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/mtdchar.c b/drivers/mtd/mtdchar.c
index 52c120f9fb0d..05f9218592df 100644
--- a/drivers/mtd/mtdchar.c
+++ b/drivers/mtd/mtdchar.c
@@ -1064,8 +1064,10 @@ static long mtdchar_compat_ioctl(struct file *file, unsigned int cmd,
 		struct mtd_oob_buf32 buf;
 		struct mtd_oob_buf32 __user *buf_user = argp;
 
-		if (!(file->f_mode & FMODE_WRITE))
-			return -EPERM;
+		if (!(file->f_mode & FMODE_WRITE)) {
+			ret = -EPERM;
+			goto unlock;
+		}
 
 		if (copy_from_user(&buf, argp, sizeof(buf)))
 			ret = -EFAULT;
@@ -1117,6 +1119,7 @@ static long mtdchar_compat_ioctl(struct file *file, unsigned int cmd,
 		ret = mtdchar_ioctl(file, cmd, (unsigned long)argp);
 	}
 
+unlock:
 	mutex_unlock(&mtd_mutex);
 
 	return ret;
-- 
2.27.0


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Re: [PATCH] mtd: unlock on error in ioctl

[Greg Kroah-Hartman]

On Mon, Jul 27, 2020 at 02:20:50PM +0300, Dan Carpenter wrote:
> We need to unlock before returning on this error path.
> 
> Fixes: 210bec567936 ("mtd: properly check all write ioctls for permissions")
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> ---
>  drivers/mtd/mtdchar.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/mtd/mtdchar.c b/drivers/mtd/mtdchar.c
> index 52c120f9fb0d..05f9218592df 100644
> --- a/drivers/mtd/mtdchar.c
> +++ b/drivers/mtd/mtdchar.c
> @@ -1064,8 +1064,10 @@ static long mtdchar_compat_ioctl(struct file *file, unsigned int cmd,
>  		struct mtd_oob_buf32 buf;
>  		struct mtd_oob_buf32 __user *buf_user = argp;
>  
> -		if (!(file->f_mode & FMODE_WRITE))
> -			return -EPERM;
> +		if (!(file->f_mode & FMODE_WRITE)) {
> +			ret = -EPERM;
> +			goto unlock;
> +		}
>  
>  		if (copy_from_user(&buf, argp, sizeof(buf)))
>  			ret = -EFAULT;
> @@ -1117,6 +1119,7 @@ static long mtdchar_compat_ioctl(struct file *file, unsigned int cmd,
>  		ret = mtdchar_ioctl(file, cmd, (unsigned long)argp);
>  	}
>  
> +unlock:
>  	mutex_unlock(&mtd_mutex);
>  
>  	return ret;
> -- 
> 2.27.0
> 

I think this is already fixed up in the mtd tree.

thanks,

greg k-h

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