ext4: require encryption feature for EXT4_IOC_SET_ENCRYPTION_POLICY

commit 9a200d075e5d05be1fcad4547a0f8aee4e2f9a04 upstream.

...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@nod.at>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index 789e2d6..bcd7c47 100644 (file)
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -622,6 +622,9 @@ resizefs_out:
                struct ext4_encryption_policy policy;
                int err = 0;
 
+               if (!ext4_has_feature_encrypt(sb))
+                       return -EOPNOTSUPP;
+
                if (copy_from_user(&policy,
                                   (struct ext4_encryption_policy __user *)arg,
                                   sizeof(policy))) {