X509_LOOKUP_HASH_DIR(3ossl) OpenSSL X509_LOOKUP_HASH_DIR(3ossl)
NAME
X509_LOOKUP_hash_dir, X509_LOOKUP_file, X509_LOOKUP_store,
X509_load_cert_file_ex, X509_load_cert_file, X509_load_crl_file,
X509_load_cert_crl_file_ex, X509_load_cert_crl_file - Default OpenSSL
certificate lookup methods
SYNOPSIS
#include <openssl/x509_vfy.h>
X509_LOOKUP_METHOD *X509_LOOKUP_hash_dir(void);
X509_LOOKUP_METHOD *X509_LOOKUP_file(void);
X509_LOOKUP_METHOD *X509_LOOKUP_store(void);
int X509_load_cert_file_ex(X509_LOOKUP *ctx, const char *file, int type,
OSSL_LIB_CTX *libctx, const char *propq);
int X509_load_cert_file(X509_LOOKUP *ctx, const char *file, int type);
int X509_load_crl_file(X509_LOOKUP *ctx, const char *file, int type);
int X509_load_cert_crl_file_ex(X509_LOOKUP *ctx, const char *file, int type,
OSSL_LIB_CTX *libctx, const char *propq);
int X509_load_cert_crl_file(X509_LOOKUP *ctx, const char *file, int type);
DESCRIPTION
X509_LOOKUP_hash_dir and X509_LOOKUP_file are two certificate lookup
methods to use with X509_STORE, provided by OpenSSL library.
Users of the library typically do not need to create instances of these
methods manually, they would be created automatically by
X509_STORE_load_locations(3) or SSL_CTX_load_verify_locations(3)
functions.
Internally loading of certificates and CRLs is implemented via
functions X509_load_cert_crl_file, X509_load_cert_file and
X509_load_crl_file. These functions support parameter type, which can
be one of constants FILETYPE_PEM, FILETYPE_ASN1 and FILETYPE_DEFAULT.
They load certificates and/or CRLs from specified file into memory
cache of X509_STORE objects which given ctx parameter is associated
with.
Functions X509_load_cert_file and X509_load_crl_file can load both PEM
and DER formats depending of type value. Because DER format cannot
contain more than one certificate or CRL object (while PEM can contain
several concatenated PEM objects) X509_load_cert_crl_file with
FILETYPE_ASN1 is equivalent to X509_load_cert_file.
Constant FILETYPE_DEFAULT with NULL filename causes these functions to
load default certificate store file (see
X509_STORE_set_default_paths(3).
Functions return number of objects loaded from file or 0 in case of
error.
Both methods support adding several certificate locations into one
X509_STORE.
This page documents certificate store formats used by these methods and
caching policy.
File Method
The X509_LOOKUP_file method loads all the certificates or CRLs present
in a file into memory at the time the file is added as a lookup source.
File format is ASCII text which contains concatenated PEM certificates
and CRLs.
This method should be used by applications which work with a small set
of CAs.
Hashed Directory Method
X509_LOOKUP_hash_dir is a more advanced method, which loads
certificates and CRLs on demand, and caches them in memory once they
are loaded. As of OpenSSL 1.0.0, it also checks for newer CRLs upon
each lookup, so that newer CRLs are as soon as they appear in the
directory.
The directory should contain one certificate or CRL per file in PEM
format, with a filename of the form hash.N for a certificate, or
hash.rN for a CRL. The hash is the value returned by the
X509_NAME_hash_ex(3) function applied to the subject name for
certificates or issuer name for CRLs. The hash can also be obtained
via the -hash option of the openssl-x509(1) or openssl-crl(1) commands.
The .N or .rN suffix is a sequence number that starts at zero, and is
incremented consecutively for each certificate or CRL with the same
hash value. Gaps in the sequence numbers are not supported, it is
assumed that there are no more objects with the same hash beyond the
first missing number in the sequence.
Sequence numbers make it possible for the directory to contain multiple
certificates with same subject name hash value. For example, it is
possible to have in the store several certificates with same subject or
several CRLs with same issuer (and, for example, different validity
period).
When checking for new CRLs once one CRL for given hash value is loaded,
hash_dir lookup method checks only for certificates with sequence
number greater than that of the already cached CRL.
Note that the hash algorithm used for subject name hashing changed in
OpenSSL 1.0.0, and all certificate stores have to be rehashed when
moving from OpenSSL 0.9.8 to 1.0.0.
OpenSSL includes a openssl-rehash(1) utility which creates symlinks
with hashed names for all files with .pem suffix in a given directory.
OSSL_STORE Method
X509_LOOKUP_store is a method that allows access to any store of
certificates and CRLs through any loader supported by ossl_store(7).
It works with the help of URIs, which can be direct references to
certificates or CRLs, but can also be references to catalogues of such
objects (that behave like directories).
This method overlaps the "File Method" and "Hashed Directory Method"
because of the 'file:' scheme loader. It does no caching of its own,
but can use a caching ossl_store(7) loader, and therefore depends on
the loader's capability.
RETURN VALUES
X509_LOOKUP_hash_dir(3), X509_LOOKUP_file() and X509_LOOKUP_store()
always return a valid X509_LOOKUP_METHOD structure.
X509_load_cert_file(), X509_load_crl_file() and
X509_load_cert_crl_file() return the number of loaded objects or 0 on
error.
SEE ALSO
PEM_read_PrivateKey(3), X509_STORE_load_locations(3),
SSL_CTX_load_verify_locations(3), X509_LOOKUP_meth_new(3),
ossl_store(7)
HISTORY
The functions X509_load_cert_file_ex(), X509_load_cert_crl_file_ex()
and X509_LOOKUP_store() were added in OpenSSL 3.0.
COPYRIGHT
Copyright 2015-2021 The OpenSSL Project Authors. All Rights Reserved.
Licensed under the Apache License 2.0 (the "License"). You may not use
this file except in compliance with the License. You can obtain a copy
in the file LICENSE in the source distribution or at
<https://www.openssl.org/source/license.html>.
3.3.2 2024-09-04 X509_LOOKUP_HASH_DIR(3ossl)
openssl 3.3.2 - Generated Sat Sep 28 11:49:12 CDT 2024