This patch adds support for using keyring for volume key
and support for new integrity fields for dm-crypt.
Also helpers for searching disk by id.
To be used later.
Also cache its value in active context, so we run benchmark
only once.
The patch also changes calculated value for LUKS1 key digest
to 125 miliseconds (it means that for full 8 used slots
the additional slow-down is circa 1 second).
Note that there is no need to have too high iteration count
for key digest; if it is too computationally expensive, attacker
will better decrypt of one sector with candidate key anyway.
(Check for a known signature.)
The reason to have some delay for key digest check was
to complicate brute-force search for volume key with LUKS header
only (and if RNG used to generate volumekey was flawed
allowing such a search i reasonable time).
Prepare API for PBKDF that can set three costs
- time (similar to iterations in PBKDF2)
- memory (required memory for memory-hard function)
- threads (required number of threads/CPUs).
This patch also removes wrongly designed API call
crypt_benchmark_kdf and replaces it with the new call
crypt_benchmark_pbkdf.
Two functions for PBKDF per context setting
are introduced: crypt_set_pbkdf_type and crypt_get_pbkdf_type.
The patch should be backward compatible when using
crypt_set_iteration_time function (works only for PBKDF2).
Signed-off-by: Milan Broz <gmazyland@gmail.com>
The Argon2i/id is a password hashing function that
won Password Hashing Competiton.
It will be (optionally) used in LUKS2 for passworrd-based
key derivation.
We have to bundle code for now (similar PBKDF2 years ago)
because there is yet no usable implementation in common
crypto libraries.
(Once there is native implementation, cryptsetup
will switch to the crypto library version.)
For now, we use reference (not optimized but portable) implementation.
This patch contains bundled Argon2 algorithm library copied from
https://github.com/P-H-C/phc-winner-argon2
For more info see Password Hashing Competition site:
https://password-hashing.net/
and draft of RFC document
https://datatracker.ietf.org/doc/draft-irtf-cfrg-argon2/
Signed-off-by: Milan Broz <gmazyland@gmail.com>
this patches improves two areas:
1) it checks for keyslot areas overlaping each other
2) it checks if all keyslot areas fit in header area of device
(pre-data-offset area) or if it can fit file (detached header)
it's being loaded from. Those new checks are based on real data
found in header (offsets) rather than based on assumption calculated
from key length
alter all checks for devfd value after device_open to
less than zero insted of equals to -1. device_open will
return values different from -1 in case error happens.
In LUKSv1 device_open should always return -1 in case of
error but this check is safer.
The rest is just formating improvement.
fix double close() cases in LUKS_hdr_backup() and LUKS_hdr_restore()
functions. It should be harmless unless libcryptsetup is used
in multi-thread setup which is not supported anyway.
- ensure that strings are \0 terminated (most of this is already
handled on higher level anyway)
- fix resource leak in error path in tcrypt.c
- fix time of check/time of use race in sysfs path processing
- insruct Coverity scanner to ignore constant expression in random.c
(it is intented to stop compile-time misconfiguration of RNG that would be fatal)
The previous PBKDF2 benchmark code did not take into account
output key length.
For SHA1 (with 160-bits output) and 256-bit keys (and longer)
it means that the final value was higher than it should be.
For other hash algorithms (like SHA256 or SHA512) it caused
that iteration count was smaller (in comparison to SHA1) than
expected for the requested time period.
This patch fixes the code to use key size for the formatted device
(or default LUKS key size if running in informational benchmark mode).
Thanks to A.Visconti, S.Bossi, A.Calo and H.Ragab
(http://www.club.di.unimi.it/) for point this out.
(Based on "What users should know about Full Disk Encryption
based on LUKS" paper to be presented on CANS2015).
The cipher_null is no-encryption, it can be used for testing
or temporarily when encrypting device (cryptsetup-reencrypt).
Accepting only empty password prevents situation when you replace
a LUKS header on an unlocking device with the faked header using
null cipher (and the same UUID).
Here a system could think that the device was properly unlocked
(with any entered password) and will try to use this unencrypted
partition instead.
(IOW it prevents situation when attacker intentionaly forces
an user to boot into dirrerent system just by LUKS header manipulation.)
Properly configured systems should have an additional integrity protection
in place here (LUKS here provides only confidentiality) but it is better
to not not allow this situation in the first place.
(Despite the fact that once you allow physical tampering of your system
it cannot be properly secured anymore.)
Apparently there are some people using ECB.
This mode by design do not use any IV, unfortunately
kernel dmcrypt allows to specify them (but userspace crypto api don't).
Let support activation as it was in previous version.
Should fix issue#238.
If user provided unusable cipher-mode string, LUKS header was written and
keyslot creation failed later.
Better check early (by creating fake dmcrypt device) if cipher is usable
and fail early (without writing LUKS header to device).
Fixes Issue#176
LUKS detached header has some limitations, one of them
is that you cannot run some explicit check for data offsets
without providing also data device.
Because luksDump and all key handle commands takes only
metadata device (LUKS heaer device), it not easy to properly
support data payload offset validation.
So if detached header is present for luksFormat, code now
allows data payload 0 (IOW whole data device is used)
and explicit offset larger than header+keyslots
(the same as the header is on data device - so some space is wasted).
N.B. with detached header the option --align-payload is used
directly without any round up caculations.
Fixes Issue#155.
