[PATCH] ext4: Check for encryption feature before fscrypt_process_policy()

From: Richard Weinberger
Date: Thu Sep 22 2016 - 02:52:06 EST

...otherwise an user can enable encryption for certain files even
when the filesystem is unable to support it.
Such a case would be a filesystem created by mkfs.ext4's default
settings, 1KiB block size. Ext4 supports encyption only when block size
is equal to PAGE_SIZE.
But this constraint is only checked when the encryption feature flag
is set.

Signed-off-by: Richard Weinberger <richard@xxxxxx>
fs/ext4/ioctl.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index 1bb7df5..9e9a73e 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -772,6 +772,9 @@ resizefs_out:
struct fscrypt_policy policy;

+ if (!ext4_has_feature_encrypt(sb))
+ return -EOPNOTSUPP;
if (copy_from_user(&policy,
(struct fscrypt_policy __user *)arg,