dm verity: set DM_TARGET_IMMUTABLE feature flag

commit 4caae58406f8ceb741603eee460d79bacca9b1b5 upstream.

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.

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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/md/dm-verity-target.c b/drivers/md/dm-verity-target.c
index 2dae30713eb3d7a417459566650be55999884e3d..77fca0432d25e5bdc11a582198ef613bf0a29a0a 100644 (file)
--- a/drivers/md/dm-verity-target.c
+++ b/drivers/md/dm-verity-target.c
@@ -1163,6 +1163,7 @@ bad:
 
 static struct target_type verity_target = {
        .name           = "verity",
+       .features       = DM_TARGET_IMMUTABLE,
        .version        = {1, 3, 0},
        .module         = THIS_MODULE,
        .ctr            = verity_ctr,