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mtd: require write permissions for locking and badblock ioctls

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[ Upstream commit 1e97743fd1 ]

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: f7e6b19bc7 ("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>
This commit is contained in:
Michael Walle 2021-03-03 16:57:35 +01:00 committed by Greg Kroah-Hartman
parent ff352d27d4
commit 5880afefe0
1 changed files with 4 additions and 4 deletions
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8
drivers/mtd/mtdchar.c
View file

@ -649,16 +649,12 @@ 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:
@ -669,9 +665,13 @@ 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;