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