[PATCH 5.10 185/530] mtd: require write permissions for locking and badblock ioctls

From: Michael Walle <redacted>

[ 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 <redacted>
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 (local)
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 b40f46a43fc6..69fb5dafa9ad 100644
--- a/drivers/mtd/mtdchar.c
+++ b/drivers/mtd/mtdchar.c

@@ -651,16 +651,12 @@ 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:

@@ -671,9 +667,13 @@ 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