1 #-----------------------------------------------------------------------
3 # Common functions for testing filesystem-level encryption
5 #-----------------------------------------------------------------------
6 # Copyright (c) 2016 Google, Inc. All Rights Reserved.
8 # Author: Eric Biggers <ebiggers@google.com>
10 # This program is free software; you can redistribute it and/or
11 # modify it under the terms of the GNU General Public License as
12 # published by the Free Software Foundation.
14 # This program is distributed in the hope that it would be useful,
15 # but WITHOUT ANY WARRANTY; without even the implied warranty of
16 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 # GNU General Public License for more details.
19 # You should have received a copy of the GNU General Public License
20 # along with this program; if not, write the Free Software Foundation,
21 # Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
22 #-----------------------------------------------------------------------
24 _require_scratch_encryption()
28 _require_xfs_io_command "set_encpolicy"
30 # The 'test_dummy_encryption' mount option interferes with trying to use
31 # encryption for real, even if we are just trying to get/set policies
32 # and never put any keys in the keyring. So skip the real encryption
33 # tests if the 'test_dummy_encryption' mount option was specified.
34 _exclude_scratch_mount_option "test_dummy_encryption"
36 # Make a filesystem on the scratch device with the encryption feature
37 # enabled. If this fails then probably the userspace tools (e.g.
38 # e2fsprogs or f2fs-tools) are too old to understand encryption.
39 if ! _scratch_mkfs_encrypted &>>$seqres.full; then
40 _notrun "$FSTYP userspace tools do not support encryption"
43 # Try to mount the filesystem. If this fails then either the kernel
44 # isn't aware of encryption, or the mkfs options were not compatible
45 # with encryption (e.g. ext4 with block size != PAGE_SIZE).
46 if ! _try_scratch_mount &>>$seqres.full; then
47 _notrun "kernel is unaware of $FSTYP encryption feature," \
48 "or mkfs options are not compatible with encryption"
51 # The kernel may be aware of encryption without supporting it. For
52 # example, for ext4 this is the case with kernels configured with
53 # CONFIG_EXT4_FS_ENCRYPTION=n. Detect support for encryption by trying
54 # to set an encryption policy. (For ext4 we could instead check for the
55 # presence of /sys/fs/ext4/features/encryption, but this is broken on
56 # some older kernels and is ext4-specific anyway.)
57 mkdir $SCRATCH_MNT/tmpdir
58 if $XFS_IO_PROG -c set_encpolicy $SCRATCH_MNT/tmpdir \
59 2>&1 >>$seqres.full | \
60 egrep -q 'Inappropriate ioctl for device|Operation not supported'
62 _notrun "kernel does not support $FSTYP encryption"
64 rmdir $SCRATCH_MNT/tmpdir
68 _scratch_mkfs_encrypted()
72 _scratch_mkfs -O encrypt
75 # erase the UBI volume; reformated automatically on next mount
76 $UBIUPDATEVOL_PROG ${SCRATCH_DEV} -t
79 _notrun "No encryption support for $FSTYP"
84 _scratch_mkfs_sized_encrypted()
88 MKFS_OPTIONS="$MKFS_OPTIONS -O encrypt" _scratch_mkfs_sized $*
91 _notrun "Filesystem $FSTYP not supported in _scratch_mkfs_sized_encrypted"
96 # Give the invoking shell a new session keyring. This makes any keys we add to
97 # the session keyring scoped to the lifetime of the test script.
98 _new_session_keyring()
100 $KEYCTL_PROG new_session >>$seqres.full
103 # Generate a key descriptor (16 character hex string)
104 _generate_key_descriptor()
108 for ((i = 0; i < 8; i++)); do
109 keydesc="${keydesc}$(printf "%02x" $(( $RANDOM % 256 )))"
114 # Generate a raw encryption key, but don't add it to the keyring yet.
115 _generate_raw_encryption_key()
119 for ((i = 0; i < 64; i++)); do
120 raw="${raw}\\x$(printf "%02x" $(( $RANDOM % 256 )))"
125 # Add the specified raw encryption key to the session keyring, using the
126 # specified key descriptor.
127 _add_encryption_key()
133 # Add the key to the session keyring. The required structure is:
135 # #define FS_MAX_KEY_SIZE 64
136 # struct fscrypt_key {
138 # u8 raw[FS_MAX_KEY_SIZE];
142 # The kernel ignores 'mode' but requires that 'size' be 64.
144 # Keys are named $FSTYP:KEYDESC where KEYDESC is the 16-character key
145 # descriptor hex string. Newer kernels (ext4 4.8 and later, f2fs 4.6
146 # and later) also allow the common key prefix "fscrypt:" in addition to
147 # their filesystem-specific key prefix ("ext4:", "f2fs:"). It would be
148 # nice to use the common key prefix, but for now use the filesystem-
149 # specific prefix to make it possible to test older kernels...
151 local big_endian=$(echo -ne '\x11' | od -tx2 | head -1 | \
152 cut -f2 -d' ' | cut -c1 )
153 if (( big_endian )); then
154 local mode='\x00\x00\x00\x00'
155 local size='\x00\x00\x00\x40'
157 local mode='\x00\x00\x00\x00'
158 local size='\x40\x00\x00\x00'
160 echo -n -e "${mode}${raw}${size}" |
161 $KEYCTL_PROG padd logon $FSTYP:$keydesc @s >>$seqres.full
165 # Generate a random encryption key, add it to the session keyring, and print out
166 # the resulting key descriptor (example: "8bf798e1a494e1ec"). Requires the
167 # keyctl program. It's assumed the caller has already set up a test-scoped
168 # session keyring using _new_session_keyring.
170 _generate_encryption_key()
172 local keydesc=$(_generate_key_descriptor)
173 local raw=$(_generate_raw_encryption_key)
175 _add_encryption_key $keydesc $raw
180 # Unlink an encryption key from the session keyring, given its key descriptor.
181 _unlink_encryption_key()
184 local keyid=$($KEYCTL_PROG search @s logon $FSTYP:$keydesc)
185 $KEYCTL_PROG unlink $keyid >>$seqres.full
188 # Revoke an encryption key from the keyring, given its key descriptor.
189 _revoke_encryption_key()
192 local keyid=$($KEYCTL_PROG search @s logon $FSTYP:$keydesc)
193 $KEYCTL_PROG revoke $keyid >>$seqres.full