2 # SPDX-License-Identifier: GPL-2.0
3 # Copyright (c) 2016 Google, Inc. All Rights Reserved.
5 # Functions for setting up and testing file encryption
7 _require_scratch_encryption()
11 _require_xfs_io_command "set_encpolicy"
13 # The 'test_dummy_encryption' mount option interferes with trying to use
14 # encryption for real, even if we are just trying to get/set policies
15 # and never put any keys in the keyring. So skip the real encryption
16 # tests if the 'test_dummy_encryption' mount option was specified.
17 _exclude_scratch_mount_option "test_dummy_encryption"
19 # Make a filesystem on the scratch device with the encryption feature
20 # enabled. If this fails then probably the userspace tools (e.g.
21 # e2fsprogs or f2fs-tools) are too old to understand encryption.
22 if ! _scratch_mkfs_encrypted &>>$seqres.full; then
23 _notrun "$FSTYP userspace tools do not support encryption"
26 # Try to mount the filesystem. If this fails then either the kernel
27 # isn't aware of encryption, or the mkfs options were not compatible
28 # with encryption (e.g. ext4 with block size != PAGE_SIZE).
29 if ! _try_scratch_mount &>>$seqres.full; then
30 _notrun "kernel is unaware of $FSTYP encryption feature," \
31 "or mkfs options are not compatible with encryption"
34 # The kernel may be aware of encryption without supporting it. For
35 # example, for ext4 this is the case with kernels configured with
36 # CONFIG_EXT4_FS_ENCRYPTION=n. Detect support for encryption by trying
37 # to set an encryption policy. (For ext4 we could instead check for the
38 # presence of /sys/fs/ext4/features/encryption, but this is broken on
39 # some older kernels and is ext4-specific anyway.)
40 mkdir $SCRATCH_MNT/tmpdir
41 if $XFS_IO_PROG -c set_encpolicy $SCRATCH_MNT/tmpdir \
42 2>&1 >>$seqres.full | \
43 egrep -q 'Inappropriate ioctl for device|Operation not supported'
45 _notrun "kernel does not support $FSTYP encryption"
47 rmdir $SCRATCH_MNT/tmpdir
51 _scratch_mkfs_encrypted()
55 _scratch_mkfs -O encrypt
58 # erase the UBI volume; reformated automatically on next mount
59 $UBIUPDATEVOL_PROG ${SCRATCH_DEV} -t
62 _notrun "No encryption support for $FSTYP"
67 _scratch_mkfs_sized_encrypted()
71 MKFS_OPTIONS="$MKFS_OPTIONS -O encrypt" _scratch_mkfs_sized $*
74 _notrun "Filesystem $FSTYP not supported in _scratch_mkfs_sized_encrypted"
79 # Give the invoking shell a new session keyring. This makes any keys we add to
80 # the session keyring scoped to the lifetime of the test script.
81 _new_session_keyring()
83 $KEYCTL_PROG new_session >>$seqres.full
86 # Generate a key descriptor (16 character hex string)
87 _generate_key_descriptor()
91 for ((i = 0; i < 8; i++)); do
92 keydesc="${keydesc}$(printf "%02x" $(( $RANDOM % 256 )))"
97 # Generate a raw encryption key, but don't add it to the keyring yet.
98 _generate_raw_encryption_key()
102 for ((i = 0; i < 64; i++)); do
103 raw="${raw}\\x$(printf "%02x" $(( $RANDOM % 256 )))"
108 # Add the specified raw encryption key to the session keyring, using the
109 # specified key descriptor.
110 _add_encryption_key()
116 # Add the key to the session keyring. The required structure is:
118 # #define FS_MAX_KEY_SIZE 64
119 # struct fscrypt_key {
121 # u8 raw[FS_MAX_KEY_SIZE];
125 # The kernel ignores 'mode' but requires that 'size' be 64.
127 # Keys are named $FSTYP:KEYDESC where KEYDESC is the 16-character key
128 # descriptor hex string. Newer kernels (ext4 4.8 and later, f2fs 4.6
129 # and later) also allow the common key prefix "fscrypt:" in addition to
130 # their filesystem-specific key prefix ("ext4:", "f2fs:"). It would be
131 # nice to use the common key prefix, but for now use the filesystem-
132 # specific prefix to make it possible to test older kernels...
134 local big_endian=$(echo -ne '\x11' | od -tx2 | head -1 | \
135 cut -f2 -d' ' | cut -c1 )
136 if (( big_endian )); then
137 local mode='\x00\x00\x00\x00'
138 local size='\x00\x00\x00\x40'
140 local mode='\x00\x00\x00\x00'
141 local size='\x40\x00\x00\x00'
143 echo -n -e "${mode}${raw}${size}" |
144 $KEYCTL_PROG padd logon $FSTYP:$keydesc @s >>$seqres.full
148 # Generate a random encryption key, add it to the session keyring, and print out
149 # the resulting key descriptor (example: "8bf798e1a494e1ec"). Requires the
150 # keyctl program. It's assumed the caller has already set up a test-scoped
151 # session keyring using _new_session_keyring.
153 _generate_encryption_key()
155 local keydesc=$(_generate_key_descriptor)
156 local raw=$(_generate_raw_encryption_key)
158 _add_encryption_key $keydesc $raw
163 # Unlink an encryption key from the session keyring, given its key descriptor.
164 _unlink_encryption_key()
167 local keyid=$($KEYCTL_PROG search @s logon $FSTYP:$keydesc)
168 $KEYCTL_PROG unlink $keyid >>$seqres.full
171 # Revoke an encryption key from the keyring, given its key descriptor.
172 _revoke_encryption_key()
175 local keyid=$($KEYCTL_PROG search @s logon $FSTYP:$keydesc)
176 $KEYCTL_PROG revoke $keyid >>$seqres.full