[RFC PATCH 3/9] common/encrypt: support checking for v2 encryption policy support

Eric Biggers
2019-08-12T17:58:03Z

Allow passing '-v 2' to _require_scratch_encryption() to check for v2
encryption policy support on the scratch device, and for xfs_io support
for setting and getting v2 encryption policies.

Signed-off-by: Eric Biggers <ebiggers@google.com>
---
common/encrypt | 41 +++++++++++++++++++++++++++++++----------
1 file changed, 31 insertions(+), 10 deletions(-)

diff --git a/common/encrypt b/common/encrypt
index a086e80f..fa6e2672 100644
--- a/common/encrypt
+++ b/common/encrypt
@@ -6,12 +6,13 @@

#
# _require_scratch_encryption [-c CONTENTS_MODE] [-n FILENAMES_MODE]
+# [-v POLICY_VERSION]
#
# Require encryption support on the scratch device.
#
-# This checks for support for the default type of encryption policy (AES-256-XTS
-# and AES-256-CTS). Options can be specified to also require support for a
-# different type of encryption policy.
+# This checks for support for the default type of encryption policy (v1 with
+# AES-256-XTS and AES-256-CTS). Options can be specified to also require
+# support for a different type of encryption policy.
#
_require_scratch_encryption()
{
@@ -68,13 +69,15 @@ _require_encryption_policy_support()
local mnt=$1
local dir=$mnt/tmpdir
local set_encpolicy_args=""
+ local policy_version=1
local c

OPTIND=2
- while getopts "c:n:" c; do
+ while getopts "c:n:v:" c; do
case $c in
- c|n)
+ c|n|v)
set_encpolicy_args+=" -$c $OPTARG"
+ [ $c = v ] && policy_version=$OPTARG
;;
*)
_fail "Unrecognized option '$c'"
@@ -87,10 +90,26 @@ _require_encryption_policy_support()
>> $seqres.full

mkdir $dir
- _require_command "$KEYCTL_PROG" keyctl
- _new_session_keyring
- local keydesc=$(_generate_session_encryption_key)
- if _set_encpolicy $dir $keydesc $set_encpolicy_args \
+ if (( policy_version > 1 )); then
+ _require_xfs_io_command "get_encpolicy" "-t"
+ local output=$(_get_encpolicy $dir -t)
+ if [ "$output" != "supported" ]; then
+ if [ "$output" = "unsupported" ]; then
+ _notrun "kernel does not support $FSTYP encryption v2 API"
+ fi
+ _fail "Unexpected output from 'get_encpolicy -t'"
+ fi
+ # Both the kernel and xfs_io support v2 encryption policies, and
+ # therefore also filesystem-level keys -- since that's the only
+ # way to provide keys for v2 policies.
+ local raw_key=$(_generate_raw_encryption_key)
+ local keyspec=$(_add_enckey $mnt "$raw_key" | awk '{print $NF}')
+ else
+ _require_command "$KEYCTL_PROG" keyctl
+ _new_session_keyring
+ local keyspec=$(_generate_session_encryption_key)
+ fi
+ if _set_encpolicy $dir $keyspec $set_encpolicy_args \
2>&1 >>$seqres.full | egrep -q 'Invalid argument'; then
_notrun "kernel does not support encryption policy: '$set_encpolicy_args'"
fi
@@ -103,7 +122,9 @@ _require_encryption_policy_support()
if ! echo foo > $dir/file; then
_notrun "encryption policy '$set_encpolicy_args' is unusable; probably missing kernel crypto API support"
fi
- $KEYCTL_PROG clear @s
+ if (( policy_version <= 1 )); then
+ $KEYCTL_PROG clear @s
+ fi
rm -r $dir
}