#----------------------------------------------------------------------- # # Common functions for testing filesystem-level encryption # #----------------------------------------------------------------------- # Copyright (c) 2016 Google, Inc. All Rights Reserved. # # Author: Eric Biggers # # 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 ! _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 } # 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 }