From 1e97743fd180981bef5f01402342bb54bf1c6366 Mon Sep 17 00:00:00 2001

From: Michael Walle <michael@walle.cc>

Date: Wed, 3 Mar 2021 16:57:35 +0100

Subject: [PATCH] mtd: require write permissions for locking and badblock ioctls

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Git-commit: 1e97743fd180981bef5f01402342bb54bf1c6366

Patch-mainline: v5.13-rc1

References: git-fixes

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

Acked-by: Takashi Iwai <tiwai@suse.de>

---

 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 998d86f46488..870f7a19ad9d 100644

--- a/drivers/mtd/mtdchar.c

+++ b/drivers/mtd/mtdchar.c

@@ -643,16 +643,12 @@ 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:

@@ -663,9 +659,13 @@ 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;

-- 

2.26.2