tests/generic/429

#! /bin/bash
# SPDX-License-Identifier: GPL-2.0
# Copyright (c) 2017 Google, Inc.  All Rights Reserved.
#
# FS QA Test No. 429
#
# Test that no-key dentries are revalidated after adding a key.  Regression test
# for:
#	28b4c263961c ("ext4 crypto: revalidate dentry after adding or removing the key")
#
# Furthermore, test that no-key dentries are *not* revalidated after "revoking"
# a key.  This used to be done, but it was broken and was removed by:
#	1b53cf9815bb ("fscrypt: remove broken support for detecting keyring key revocation")
#
# Also test for a race condition bug in 28b4c263961c, fixed by:
#	03a8bb0e53d9 ("ext4/fscrypto: avoid RCU lookup in d_revalidate")
#
# Note: the following fix for another race in 28b4c263961c should be applied as
# well, though we don't test for it because it's very difficult to reproduce:
#	3d43bcfef5f0 ("ext4 crypto: use dget_parent() in ext4_d_revalidate()")
#
. ./common/preamble
_begin_fstest auto encrypt

# Import common functions.
. ./common/filter
. ./common/encrypt

_require_scratch_encryption
_require_command "$KEYCTL_PROG" keyctl
_require_test_program "t_encrypted_d_revalidate"

# Set up an encrypted directory
_scratch_mkfs_encrypted &>> $seqres.full
_scratch_mount
_init_session_keyring
keydesc=$(_generate_key_descriptor)
raw_key=$(_generate_raw_encryption_key)
mkdir $SCRATCH_MNT/edir
_add_session_encryption_key $keydesc $raw_key
_set_encpolicy $SCRATCH_MNT/edir $keydesc

# Create two files in the directory: one whose name is valid in the base64
# format used in no-key filenames, and one whose name is not.  The exact
# filenames *should* be irrelevant, but due to yet another bug, ->lookup() in an
# encrypted directory without the key returned ERR_PTR(-ENOENT) rather than NULL
# if the name was not a valid no-key name, causing a negative dentry to not be
# created.  For the purpose of this test, we want at least one negative dentry
# to be created, so just create both types of name.
echo contents_@@@ > $SCRATCH_MNT/edir/@@@ # not valid base64
echo contents_abcd > $SCRATCH_MNT/edir/abcd # valid base64

show_file_contents()
{
	echo "--- Contents of files using plaintext names:"
	cat $SCRATCH_MNT/edir/@@@ |& _filter_scratch
	cat $SCRATCH_MNT/edir/abcd |& _filter_scratch
	echo "--- Contents of files using no-key names:"
	cat ${nokey_names[@]} |& _filter_scratch | _filter_nokey_filenames edir
}

show_directory_with_key()
{
	echo "--- Directory listing:"
	find $SCRATCH_MNT/edir -mindepth 1 | sort | _filter_scratch
	show_file_contents
}

# View the directory without the encryption key.  The plaintext names shouldn't
# exist, but 'cat' each to verify this, which also should create negative
# dentries.  The no-key names are unpredictable by design, but verify that the
# correct number of them are listed by readdir, and save them for later.
echo
echo "***** Without encryption key *****"
_unlink_session_encryption_key $keydesc
_scratch_cycle_mount
echo "--- Directory listing:"
nokey_names=( $(find $SCRATCH_MNT/edir -mindepth 1 | sort) )
printf '%s\n' "${nokey_names[@]}" | \
	_filter_scratch | _filter_nokey_filenames edir
show_file_contents

# Without remounting or dropping caches, add the encryption key and view the
# directory again.  Now the plaintext names should all be there, and the no-key
# names should be gone.  Make sure to 'cat' all the names to test for stale
# dentries.
echo
echo "***** With encryption key *****"
_add_session_encryption_key $keydesc $raw_key
show_directory_with_key

# Test for ->d_revalidate() race conditions.
echo
echo "***** Race conditions *****"
$here/src/t_encrypted_d_revalidate $SCRATCH_MNT/edir
rm -rf $SCRATCH_MNT/edir/dir

# Now open the files to pin them in the inode cache (needed to make the test
# reliable), then revoke the encryption key.  This should no longer cause the
# files to be presented in no-key form immediately.
echo
echo "***** After key revocation *****"
(
	exec 3<$SCRATCH_MNT/edir
	exec 4<$SCRATCH_MNT/edir/@@@
	exec 5<$SCRATCH_MNT/edir/abcd
	_revoke_session_encryption_key $keydesc
	show_directory_with_key
)

# success, all done
status=0
exit