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
           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 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)