blob: 3d77ebd2cecca516fc7fe08679d6f37179ecafe3 [file] [log] [blame]
#-----------------------------------------------------------------------
#
# Common functions for testing filesystem-level encryption
#
#-----------------------------------------------------------------------
# Copyright (c) 2016 Google, Inc. All Rights Reserved.
#
# Author: Eric Biggers <ebiggers@google.com>
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License as
# published by the Free Software Foundation.
#
# This program is distributed in the hope that it would be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write the Free Software Foundation,
# Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
#-----------------------------------------------------------------------
_require_scratch_encryption()
{
_require_scratch
_require_xfs_io_command "set_encpolicy"
# The 'test_dummy_encryption' mount option interferes with trying to use
# encryption for real, even if we are just trying to get/set policies
# and never put any keys in the keyring. So skip the real encryption
# tests if the 'test_dummy_encryption' mount option was specified.
_exclude_scratch_mount_option "test_dummy_encryption"
# Make a filesystem on the scratch device with the encryption feature
# enabled. If this fails then probably the userspace tools (e.g.
# e2fsprogs or f2fs-tools) are too old to understand encryption.
if ! _scratch_mkfs_encrypted &>>$seqres.full; then
_notrun "$FSTYP userspace tools do not support encryption"
fi
# Try to mount the filesystem. If this fails then either the kernel
# isn't aware of encryption, or the mkfs options were not compatible
# with encryption (e.g. ext4 with block size != PAGE_SIZE).
if ! _try_scratch_mount &>>$seqres.full; then
_notrun "kernel is unaware of $FSTYP encryption feature," \
"or mkfs options are not compatible with encryption"
fi
# The kernel may be aware of encryption without supporting it. For
# example, for ext4 this is the case with kernels configured with
# CONFIG_EXT4_FS_ENCRYPTION=n. Detect support for encryption by trying
# to set an encryption policy. (For ext4 we could instead check for the
# presence of /sys/fs/ext4/features/encryption, but this is broken on
# some older kernels and is ext4-specific anyway.)
mkdir $SCRATCH_MNT/tmpdir
if $XFS_IO_PROG -c set_encpolicy $SCRATCH_MNT/tmpdir \
2>&1 >>$seqres.full | \
egrep -q 'Inappropriate ioctl for device|Operation not supported'
then
_notrun "kernel does not support $FSTYP encryption"
fi
rmdir $SCRATCH_MNT/tmpdir
_scratch_unmount
}
_scratch_mkfs_encrypted()
{
case $FSTYP in
ext4|f2fs)
_scratch_mkfs -O encrypt
;;
ubifs)
# erase the UBI volume; reformated automatically on next mount
$UBIUPDATEVOL_PROG ${SCRATCH_DEV} -t
;;
*)
_notrun "No encryption support for $FSTYP"
;;
esac
}
_scratch_mkfs_sized_encrypted()
{
case $FSTYP in
ext4|f2fs)
MKFS_OPTIONS="$MKFS_OPTIONS -O encrypt" _scratch_mkfs_sized $*
;;
*)
_notrun "Filesystem $FSTYP not supported in _scratch_mkfs_sized_encrypted"
;;
esac
}
# Give the invoking shell a new session keyring. This makes any keys we add to
# the session keyring scoped to the lifetime of the test script.
_new_session_keyring()
{
$KEYCTL_PROG new_session >>$seqres.full
}
# Generate a key descriptor (16 character hex string)
_generate_key_descriptor()
{
local keydesc=""
local i
for ((i = 0; i < 8; i++)); do
keydesc="${keydesc}$(printf "%02x" $(( $RANDOM % 256 )))"
done
echo $keydesc
}
# Generate a raw encryption key, but don't add it to the keyring yet.
_generate_raw_encryption_key()
{
local raw=""
local i
for ((i = 0; i < 64; i++)); do
raw="${raw}\\x$(printf "%02x" $(( $RANDOM % 256 )))"
done
echo $raw
}
# Add the specified raw encryption key to the session keyring, using the
# specified key descriptor.
_add_encryption_key()
{
local keydesc=$1
local raw=$2
#
# Add the key to the session keyring. The required structure is:
#
# #define FS_MAX_KEY_SIZE 64
# struct fscrypt_key {
# u32 mode;
# u8 raw[FS_MAX_KEY_SIZE];
# u32 size;
# } __packed;
#
# The kernel ignores 'mode' but requires that 'size' be 64.
#
# Keys are named $FSTYP:KEYDESC where KEYDESC is the 16-character key
# descriptor hex string. Newer kernels (ext4 4.8 and later, f2fs 4.6
# and later) also allow the common key prefix "fscrypt:" in addition to
# their filesystem-specific key prefix ("ext4:", "f2fs:"). It would be
# nice to use the common key prefix, but for now use the filesystem-
# specific prefix to make it possible to test older kernels...
#
local big_endian=$(echo -ne '\x11' | od -tx2 | head -1 | \
cut -f2 -d' ' | cut -c1 )
if (( big_endian )); then
local mode='\x00\x00\x00\x00'
local size='\x00\x00\x00\x40'
else
local mode='\x00\x00\x00\x00'
local size='\x40\x00\x00\x00'
fi
echo -n -e "${mode}${raw}${size}" |
$KEYCTL_PROG padd logon $FSTYP:$keydesc @s >>$seqres.full
}
#
# Generate a random encryption key, add it to the session keyring, and print out
# the resulting key descriptor (example: "8bf798e1a494e1ec"). Requires the
# keyctl program. It's assumed the caller has already set up a test-scoped
# session keyring using _new_session_keyring.
#
_generate_encryption_key()
{
local keydesc=$(_generate_key_descriptor)
local raw=$(_generate_raw_encryption_key)
_add_encryption_key $keydesc $raw
echo $keydesc
}
# Unlink an encryption key from the session keyring, given its key descriptor.
_unlink_encryption_key()
{
local keydesc=$1
local keyid=$($KEYCTL_PROG search @s logon $FSTYP:$keydesc)
$KEYCTL_PROG unlink $keyid >>$seqres.full
}
# Revoke an encryption key from the keyring, given its key descriptor.
_revoke_encryption_key()
{
local keydesc=$1
local keyid=$($KEYCTL_PROG search @s logon $FSTYP:$keydesc)
$KEYCTL_PROG revoke $keyid >>$seqres.full
}