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 48832f9b215c..ee437af41f11 100644 --- a/drivers/mtd/mtdchar.c +++ b/drivers/mtd/mtdchar.c @@ -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;