linux-kernel - [PATCH] mtd: unlock on error in ioctl

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Message-ID: <20200727112050.GF389488@mwanda>
Date:   Mon, 27 Jul 2020 14:20:50 +0300
From:   Dan Carpenter <dan.carpenter@...cle.com>
To:     Miquel Raynal <miquel.raynal@...tlin.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     Richard Weinberger <richard@....at>,
        Vignesh Raghavendra <vigneshr@...com>,
        linux-mtd@...ts.infradead.org, linux-kernel@...r.kernel.org,
        kernel-janitors@...r.kernel.org
Subject: [PATCH] mtd: unlock on error in ioctl

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@...cle.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