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CRYPT_CHECKSALT(3)       BSD Library Functions Manual       CRYPT_CHECKSALT(3)

NAME
     crypt_checksalt — validate a crypt setting string

LIBRARY
     Crypt Library (libcrypt, -lcrypt)

SYNOPSIS
     #include <crypt.h>

     int
     crypt_checksalt(const char *setting);

DESCRIPTION
     crypt_checksalt checks the setting string against the system configuration and reports whether
     the hashing method and parameters it specifies are acceptable.  It is intended to be used by
     programs such as login(1) to determine whether the user's passphrase should be re-hashed using
     the currently preferred hashing method.

RETURN VALUES
     The return value is 0 if there is nothing wrong with this setting.  Otherwise, it is one of the
     following constants:

     CRYPT_SALT_OK
           setting is a fully correct setting string.  This constant is guaranteed to equal 0.

     CRYPT_SALT_INVALID
           setting is not a valid setting string; either it specifies a hashing method that is not
           known to this version of libxcrypt, or it specifies invalid parameters for the method.

     CRYPT_SALT_METHOD_DISABLED (Not implemented, yet)
           setting specifies a hashing method that is no longer allowed to be used at all; crypt
           will fail if passed this setting.  Manual intervention will be required to reactivate the
           user's account.

     CRYPT_SALT_METHOD_LEGACY
           setting specifies a hashing method that is no longer considered strong enough for use
           with new passphrases.  crypt will still authenticate a passphrase against this setting,
           but if authentication succeeds, the passphrase should be re-hashed using the currently
           preferred method.

     CRYPT_SALT_TOO_CHEAP (Not implemented, yet)
           setting specifies cost parameters that are considered too cheap for use with new
           passphrases.  crypt will still authenticate a passphrase against this setting, but if au‐
           thentication succeeds, the passphrase should be re-hashed using the currently preferred
           method.

FEATURE TEST MACROS
     <crypt.h> will define the macro CRYPT_CHECKSALT_AVAILABLE if crypt_checksalt is available in
     the current version of libxcrypt.

BUGS
     Since full configurability is not yet implemented, the current implementation will only ever
     return CRYPT_SALT_OK (0) or CRYPT_SALT_INVALID when invoked.

PORTABILITY NOTES
     The function crypt_checksalt is not part of any standard.  It was added to libxcrypt in version
     4.3.0.

ATTRIBUTES
     For an explanation of the terms used in this section, see attributes(7).




     ┌────────────────┬───────────────┬─────────┐
     │Interface       │ Attribute     │ Value   │
     ├────────────────┼───────────────┼─────────┤
     │crypt_checksalt │ Thread safety │ MT-Safe │
     └────────────────┴───────────────┴─────────┘

SEE ALSO
     crypt(3), crypt_gensalt(3), crypt(5)

libxcrypt                      November 8, 2018                      libxcrypt