From 4caae58406f8ceb741603eee460d79bacca9b1b5 Mon Sep 17 00:00:00 2001
From: Sarthak Kukreti <sarthakkukreti@google.com>
Date: Tue, 31 May 2022 15:56:40 -0400
Subject: [PATCH] dm verity: set DM_TARGET_IMMUTABLE feature flag
Git-commit: 4caae58406f8ceb741603eee460d79bacca9b1b5
Patch-mainline: v5.19-rc1
References: CVE-2022-2503, bsc#1202677

The device-mapper framework provides a mechanism to mark targets as
immutable (and hence fail table reloads that try to change the target
type). Add the DM_TARGET_IMMUTABLE flag to the dm-verity target's
feature flags to prevent switching the verity target with a different
target type.

(Coly Li: rebased for Linux v4.12 based SUSE kernel)

Fixes: a4ffc152198e ("dm: add verity target")
Cc: stable@vger.kernel.org
Signed-off-by: Sarthak Kukreti <sarthakkukreti@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Coly Li <colyli@suse.de>
---
 drivers/md/dm-verity-target.c |    1 +
 1 file changed, 1 insertion(+)

--- a/drivers/md/dm-verity-target.c
+++ b/drivers/md/dm-verity-target.c
@@ -1137,6 +1137,7 @@ bad:
 
 static struct target_type verity_target = {
 	.name		= "verity",
+	.features	= DM_TARGET_IMMUTABLE,
 	.version	= {1, 3, 0},
 	.module		= THIS_MODULE,
 	.ctr		= verity_ctr,