The crypt_keyslot_add_by_keyslot_context & associated
helper functions allow more options when adding new
keyslot. For example there was no simple way of
adding new LUKS2 keyslot when the only active keyslot
could be unlocked by passphrase (KEK) provided by LUKS2 token
(plugin). Now all available options for unlocking keyslots
may also be used when creating new keyslot and it combine
as called needs.
The available methods (keyslot contexts) are:
passphrase, keyfile, key (binary representation) and LUSK2 token.
System FIPS mode check is no longer dependent on /etc/system-fips
file. The change should be compatible with older distributions since
we now depend on crypto backend internal routine.
This commit affects only FIPS enabled systems (with FIPS enabled
builds). In case this causes any regression in current distributions
feel free to drop the patch.
For reference see https://bugzilla.redhat.com/show_bug.cgi?id=2080516
Fix possible attacks against data confidentiality through LUKS2 online
reencryption extension crash recovery.
An attacker can modify on-disk metadata to simulate decryption in
progress with crashed (unfinished) reencryption step and persistently
decrypt part of the LUKS device.
This attack requires repeated physical access to the LUKS device but
no knowledge of user passphrases.
The decryption step is performed after a valid user activates
the device with a correct passphrase and modified metadata.
There are no visible warnings for the user that such recovery happened
(except using the luksDump command). The attack can also be reversed
afterward (simulating crashed encryption from a plaintext) with
possible modification of revealed plaintext.
The problem was caused by reusing a mechanism designed for actual
reencryption operation without reassessing the security impact for new
encryption and decryption operations. While the reencryption requires
calculating and verifying both key digests, no digest was needed to
initiate decryption recovery if the destination is plaintext (no
encryption key). Also, some metadata (like encryption cipher) is not
protected, and an attacker could change it. Note that LUKS2 protects
visible metadata only when a random change occurs. It does not protect
against intentional modification but such modification must not cause
a violation of data confidentiality.
The fix introduces additional digest protection of reencryption
metadata. The digest is calculated from known keys and critical
reencryption metadata. Now an attacker cannot create correct metadata
digest without knowledge of a passphrase for used keyslots.
For more details, see LUKS2 On-Disk Format Specification version 1.1.0.
The external gettext library should be used on main libcryptsetup,
not later for programs (these do not call any translations).
(Also it was in the wrong order there failing compilation.)
Starting with GCC10 and LTO enabled, current symbols
versioning hack does not work anymore. This patch
reflects on that and should be compatible with older
compilers that does not support __attribute__((symver))
yet.
Inspired by following code:
https://github.com/linux-rdma/rdma-core/blob/master/util/symver.h
To avoid confusion, use just one lib include and specify sub-directories
for format inclusions.
This should also help some analysis tools to find proper includes.
Introducing new library supposed to be used in
cryptsetup tools and future cryptsetup loadable plugins
TODO:
- distribution
- cleanup header files
- incorporate also plugin API?
