doc/man3/X509_LOOKUP_hash_dir.pod - third_party/openssl - Git at Google

 =pod

 =head1 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

 =head1 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);

 =head1 DESCRIPTION

 B<X509_LOOKUP_hash_dir> and B<X509_LOOKUP_file> are two certificate
 lookup methods to use with B<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
 L<X509_STORE_load_locations(3)> or
 L<SSL_CTX_load_verify_locations(3)>
 functions.

 Internally loading of certificates and CRLs is implemented via functions
 B<X509_load_cert_crl_file>, B<X509_load_cert_file> and
 B<X509_load_crl_file>. These functions support parameter I<type>, which
 can be one of constants B<FILETYPE_PEM>, B<FILETYPE_ASN1> and
 B<FILETYPE_DEFAULT>. They load certificates and/or CRLs from specified
 file into memory cache of B<X509_STORE> objects which given B<ctx>
 parameter is associated with.

 Functions B<X509_load_cert_file> and
 B<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)
 B<X509_load_cert_crl_file> with B<FILETYPE_ASN1> is equivalent to
 B<X509_load_cert_file>.

 Constant B<FILETYPE_DEFAULT> with NULL filename causes these functions
 to load default certificate store file (see
 L<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
 B<X509_STORE>.

 This page documents certificate store formats used by these methods and
 caching policy.

 =head2 File Method

 The B<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.

 =head2 Hashed Directory Method

 B<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 I<hash>.I<N> for a certificate, or
 I<hash>.B<r>I<N> for a CRL.
 The I<hash> is the value returned by the L<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 B<-hash> option of the
 L<openssl-x509(1)> or L<openssl-crl(1)> commands.

 The .I<N> or .B<r>I<N> suffix is a sequence number that starts at zero, and is
 incremented consecutively for each certificate or CRL with the same I<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 L<openssl-rehash(1)> utility which creates symlinks with
 hashed names for all files with F<.pem> suffix in a given directory.

 =head2 OSSL_STORE Method

 B<X509_LOOKUP_store> is a method that allows access to any store of
 certificates and CRLs through any loader supported by
 L<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 L</File Method> and L</Hashed Directory Method>
 because of the 'file:' scheme loader.
 It does no caching of its own, but can use a caching L<ossl_store(7)>
 loader, and therefore depends on the loader's capability.

 =head1 RETURN VALUES

 X509_LOOKUP_hash_dir(), X509_LOOKUP_file() and X509_LOOKUP_store()
 always return a valid B<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.

 =head1 SEE ALSO

 L<PEM_read_PrivateKey(3)>,
 L<X509_STORE_load_locations(3)>,
 L<SSL_CTX_load_verify_locations(3)>,
 L<X509_LOOKUP_meth_new(3)>,
 L<ossl_store(7)>

 =head1 HISTORY

 The functions X509_load_cert_file_ex(),
 X509_load_cert_crl_file_ex() and X509_LOOKUP_store() were added in
 OpenSSL 3.0.

 =head1 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
 L<https://www.openssl.org/source/license.html>.

 =cut
	=pod

	=head1 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

	=head1 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);

	=head1 DESCRIPTION

	B<X509_LOOKUP_hash_dir> and B<X509_LOOKUP_file> are two certificate
	lookup methods to use with B<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
	L<X509_STORE_load_locations(3)> or
	L<SSL_CTX_load_verify_locations(3)>
	functions.

	Internally loading of certificates and CRLs is implemented via functions
	B<X509_load_cert_crl_file>, B<X509_load_cert_file> and
	B<X509_load_crl_file>. These functions support parameter I<type>, which
	can be one of constants B<FILETYPE_PEM>, B<FILETYPE_ASN1> and
	B<FILETYPE_DEFAULT>. They load certificates and/or CRLs from specified
	file into memory cache of B<X509_STORE> objects which given B<ctx>
	parameter is associated with.

	Functions B<X509_load_cert_file> and
	B<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)
	B<X509_load_cert_crl_file> with B<FILETYPE_ASN1> is equivalent to
	B<X509_load_cert_file>.

	Constant B<FILETYPE_DEFAULT> with NULL filename causes these functions
	to load default certificate store file (see
	L<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
	B<X509_STORE>.

	This page documents certificate store formats used by these methods and
	caching policy.

	=head2 File Method

	The B<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.

	=head2 Hashed Directory Method

	B<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 I<hash>.I<N> for a certificate, or
	I<hash>.B<r>I<N> for a CRL.
	The I<hash> is the value returned by the L<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 B<-hash> option of the
	L<openssl-x509(1)> or L<openssl-crl(1)> commands.

	The .I<N> or .B<r>I<N> suffix is a sequence number that starts at zero, and is
	incremented consecutively for each certificate or CRL with the same I<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 L<openssl-rehash(1)> utility which creates symlinks with
	hashed names for all files with F<.pem> suffix in a given directory.

	=head2 OSSL_STORE Method

	B<X509_LOOKUP_store> is a method that allows access to any store of
	certificates and CRLs through any loader supported by
	L<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 L</File Method> and L</Hashed Directory Method>
	because of the 'file:' scheme loader.
	It does no caching of its own, but can use a caching L<ossl_store(7)>
	loader, and therefore depends on the loader's capability.

	=head1 RETURN VALUES

	X509_LOOKUP_hash_dir(), X509_LOOKUP_file() and X509_LOOKUP_store()
	always return a valid B<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.

	=head1 SEE ALSO

	L<PEM_read_PrivateKey(3)>,
	L<X509_STORE_load_locations(3)>,
	L<SSL_CTX_load_verify_locations(3)>,
	L<X509_LOOKUP_meth_new(3)>,
	L<ossl_store(7)>

	=head1 HISTORY

	The functions X509_load_cert_file_ex(),
	X509_load_cert_crl_file_ex() and X509_LOOKUP_store() were added in
	OpenSSL 3.0.

	=head1 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
	L<https://www.openssl.org/source/license.html>.

	=cut