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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Michael Walle <michael@walle.cc>,
        =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>,
        Richard Weinberger <richard@nod.at>,
        Miquel Raynal <miquel.raynal@bootlin.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.9 107/240] mtd: require write permissions for locking and badblock ioctls
Date:   Thu, 20 May 2021 11:21:39 +0200
Message-Id: <20210520092112.271357965@linuxfoundation.org>
In-Reply-To: <20210520092108.587553970@linuxfoundation.org>
References: <20210520092108.587553970@linuxfoundation.org>
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From: Michael Walle <michael@walle.cc>

[ Upstream commit 1e97743fd180981bef5f01402342bb54bf1c6366 ]

MEMLOCK, MEMUNLOCK and OTPLOCK modify protection bits. Thus require
write permission. Depending on the hardware MEMLOCK might even be
write-once, e.g. for SPI-NOR flashes with their WP# tied to GND. OTPLOCK
is always write-once.

MEMSETBADBLOCK modifies the bad block table.

Fixes: f7e6b19bc764 ("mtd: properly check all write ioctls for permissions")
Signed-off-by: Michael Walle <michael@walle.cc>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Rafał Miłecki <rafal@milecki.pl>
Acked-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20210303155735.25887-1-michael@walle.cc
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/mtd/mtdchar.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/mtd/mtdchar.c b/drivers/mtd/mtdchar.c
index 331183548bc5..b43b8edc18ec 100644
--- a/drivers/mtd/mtdchar.c
+++ b/drivers/mtd/mtdchar.c
@@ -689,16 +689,12 @@ static int mtdchar_ioctl(struct file *file, u_int cmd, u_long arg)
 	case MEMGETINFO:
 	case MEMREADOOB:
 	case MEMREADOOB64:
-	case MEMLOCK:
-	case MEMUNLOCK:
 	case MEMISLOCKED:
 	case MEMGETOOBSEL:
 	case MEMGETBADBLOCK:
-	case MEMSETBADBLOCK:
 	case OTPSELECT:
 	case OTPGETREGIONCOUNT:
 	case OTPGETREGIONINFO:
-	case OTPLOCK:
 	case ECCGETLAYOUT:
 	case ECCGETSTATS:
 	case MTDFILEMODE:
@@ -709,9 +705,13 @@ static int mtdchar_ioctl(struct file *file, u_int cmd, u_long arg)
 	/* "dangerous" commands */
 	case MEMERASE:
 	case MEMERASE64:
+	case MEMLOCK:
+	case MEMUNLOCK:
+	case MEMSETBADBLOCK:
 	case MEMWRITEOOB:
 	case MEMWRITEOOB64:
 	case MEMWRITE:
+	case OTPLOCK:
 		if (!(file->f_mode & FMODE_WRITE))
 			return -EPERM;
 		break;
-- 
2.30.2