This patch avoid warning in constant-time base64 function:
Error: CPPCHECK_WARNING (CWE-190): [#def2]
cryptsetup-main/lib/crypto_backend/argon2/encoding.c:86: error[integerOverflow]: Signed integer overflow for expression ''0'-52'.
The (x + ('0' - 52)) can be rewritten to (x - (52 - '0')) with the same effect.
Similar solution used in https://github.com/pornin/CTTK/blob/master/src/base64.c
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>
