Header write can call falloc() to increase image size, so we should
check data offset after header is written.
Also change wording to be less cryptic and describe what is the real problem.
Note that the code can be used this way to crate detached header (without
space for data), so it is not an error.
Extends avaiable methods for retrieving device volume key.
The volume key now may be extracted using passphrase, keyfile
(passphrase in a file) or token (LUKS2 only).
For LUKS devices, it returns generated volume key after
sucessfull crypt_format where new volume key got generated.
Fixes: #777.
First, there was a bug where passphrase based
keyslot contextets did not cache volume keys
properly and caused leaks.
Second, it causes problems when keyslot context
is used twice with different keyslot id, e.g.:
CRYPT_ANY_SLOT vs specific id, unbound key vs
volume key, etc.
The function is supposed to check if manipulated
active dm-crypt device matches the on-disk metadata.
Unfortunately it did not take into account differences
between normal cipher specification (aes-xts-plain64)
and capi format specification (capi:xts(aes)-plain64).
The internal query function always converted capi format
in normal format and therefor failed if capi format was
used in metadata.
Fixes: #759.
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.
json-c parser transforms NULL pointer into special '(null)' string.
While being technically correct it hides the fact user passed NULL
pointer in crypt_token_params_luks2_keyring structure. This bug
could be trigerred by calling crypt_token_luks2_keyring_set().
Following API calls trigerred LUKS2 metadata reload
from storage in case of failure:
crypt_convert
crypt_keyslot_add_by_key
crypt_keyslot_add_by_keyfile_device_offset
crypt_keyslot_add_by_passphrase
crypt_keyslot_change_by_passphrase
crypt_reencrypt_init_by_keyring
crypt_reencrypt_init_by_passphrase
This patch replaces LUKS2 metadata reload with
backup LUKS2 metadata copy kept in memory that is updated on
each sucessfull metadata write and rolled back to it whenever
needed in any of those calls listed above.
Empty context or any non-LUKS types now returns
CRYPT_REENCRYPT_INVALID value.
For LUKS1 devices return CRYPT_REENCRYPT_NONE
(since any LUKS1 device in legacy reencryption
does not have valid LUKS1 header/metadata).
Ths will allow automatic scan of known formats.
Errors are printed only if something is wrong with already detected metadata.
This change means that it is responsibility of the caller to print an error
message if needed.
Also fix some places without a message.
Fixes: #642
INTEGRITY_key_size returns -EINVAL for algorithms without a key
and because crypt_params_integrity.integrity_key_size is an
unsigned integer we get key size 4294967274 instead of more
appropriate 0 for these algorithms.
Calculating device sizes for verity devices is a little bit tricky,
Data, hash and FEC can share devices or it can be a separate devices.
This patch prints used device sizes in veritysetup dump command,
but it requires that user specifies all values that are not stored
in superblock (like a FEC device and FEC roots).
To allow resizing integrity devices with detached metadata device, the
check has to be moved from _compare_integrity_devices to
_reload_device_with_integrity.
If the provided key is NULL, we load it from the active device. This is
always available, since keyring keys are not supported in kernel for
integrity devices.
Move code setting data device during format so that
we can properly detect optimal encryption sector size
for data device instead of metadata device (header).
Fixes: #708.
Attribute unused is useless and makes code imcomprehensible
when decorates internal functions not exposed via API.
Let's cleanup internal funtion prototypes whenever possible.
The option --disable-luks2-reencryption completely disable
LUKS2 reencryption code.
When used, the libcryptsetup library can read metadata with
reencryption code, but all reencryption API calls and cryptsetup
reencrypt commands are disabled.
Devices with online reencryption in progress cannot be activated.
This option can cause some incompatibilities. Please use with care.
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.
Reverts commit 96d83455ca partially. It is not necessary to
have specific crypt_activate_by_token_type call. Users
may use crypt_activate_by_token_pin with pin argument set to NULL
and achieve same goal as with crypt_activate_by_token_type.
