CRYPT_CHECKSALT(3) 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 in-
tervention 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 au-
thenticate a passphrase against this setting, but if authentica-
tion succeeds, the passphrase should be re-hashed using the cur-
rently 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 CRYPT_CHECKSALT(3)
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