crypt_checksalt

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 configura-
     tion 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.  Oth-
     erwise, it is one of the following constants:

     CRYPT_SALT_OK
           setting is a fully correct setting string.  This constant is guar-
           anteed to equal 0.

     CRYPT_SALT_INVALID
           setting is not a valid setting string; either it specifies a hash-
           ing 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 inter-
           vention will be required to reactivate the user's account.

     CRYPT_SALT_METHOD_LEGACY (Not implemented, yet)
           setting specifies a hashing method that is no longer considered
           strong enough for use with new passphrases.  crypt will still au-
           thenticate 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 authentication 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 implemen-
     tation 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