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Document more X509_STORE functions

X509_STORE_set_verify_cb_func.pod has documentation for various callbacks
and function pointers that can be set and retrieved, but neither it nor
X509_STORE_new has much documentation for the actual purpose and usage
of X509_STORE objects.  Remedy this disparity with new documentation
for adding certificates and CRLs, expected usage, and for modifying
the default verifification behavior.

Reviewed-by: Richard Levitte <>
Reviewed-by: Tim Hudson <>
Reviewed-by: Viktor Dukhovni <>
(Merged from
Benjamin Kaduk 5 years ago
committed by Benjamin Kaduk
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doc/man3/X509_STORE_add_cert.pod View File

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=head1 NAME
X509_STORE_add_cert, X509_STORE_add_crl, X509_STORE_set_depth,
X509_STORE_set_flags, X509_STORE_set_purpose, X509_STORE_set_trust,
- X509_STORE manipulation
#include <openssl/x509_vfy.h>
int X509_STORE_add_cert(X509_STORE *ctx, X509 *x);
int X509_STORE_add_crl(X509_STORE *ctx, X509_CRL *x);
int X509_STORE_set_depth(X509_STORE *store, int depth);
int X509_STORE_set_flags(X509_STORE *ctx, unsigned long flags);
int X509_STORE_set_purpose(X509_STORE *ctx, int purpose);
int X509_STORE_set_trust(X509_STORE *ctx, int trust);
int X509_STORE_load_locations(X509_STORE *ctx,
const char *file, const char *dir);
int X509_STORE_set_default_paths(X509_STORE *ctx);
The B<X509_STORE> structure is intended to be a consolidated mechanism for
holding information about X.509 certificates and CRLs, and constructing
and validating chains of certificates terminating in trusted roots.
It admits multiple lookup mechanisms and efficient scaling performance
with large numbers of certificates, and a great deal of flexibility in
how validation and policy checks are performed.
L<X509_STORE_new(3)> creates an empty B<X509_STORE> structure, which contains
no information about trusted certificates or where such certificates
are located on disk, and is generally not usable. Normally, trusted
certificates will be added to the B<X509_STORE> to prepare it for use,
via mechanisms such as X509_STORE_add_lookup() and X509_LOOKUP_file(), or
PEM_read_bio_X509_AUX() and X509_STORE_add_cert(). CRLs can also be added,
and many behaviors configured as desired.
Once the B<X509_STORE> is suitably configured, X509_STORE_CTX_new() is
used to instantiate a single-use B<X509_STORE_CTX> for each chain-building
and verification operation. That process includes providing the end-entity
certificate to be verified and an additional set of untrusted certificates
that may be used in chain-building. As such, it is expected that the
certificates included in the B<X509_STORE> are certificates that represent
trusted entities such as root certificate authorities (CAs).
OpenSSL represents these trusted certificates internally as B<X509> objects
with an associated B<X509_CERT_AUX>, as are produced by
PEM_read_bio_X509_AUX() and similar routines that refer to X509_AUX.
The public interfaces that operate on such trusted certificates still
operate on pointers to B<X509> objects, though.
X509_STORE_add_cert() and X509_STORE_add_crl() add the respective object
to the B<X509_STORE>'s local storage. Untrusted objects should not be
added in this way.
X509_STORE_set_depth(), X509_STORE_set_flags(), X509_STORE_set_purpose(),
X509_STORE_set_trust(), and X509_STORE_set1_param() set the default values
for the corresponding values used in certificate chain validation. Their
behavior is documented in the corresponding B<X509_VERIFY_PARAM> manual
pages, e.g., L<X509_VERIFY_PARAM_set_depth(3)>.
X509_STORE_load_locations() loads trusted certificate(s) into an
B<X509_STORE> from a given file and/or directory path. It is permitted
to specify just a file, just a directory, or both paths. The certificates
in the directory must be in hashed form, as documented in
X509_STORE_set_default_paths() is somewhat misnamed, in that it does not
set what default paths should be used for loading certificates. Instead,
it loads certificates into the B<X509_STORE> from the hardcoded default
X509_STORE_add_cert(), X509_STORE_add_crl(), X509_STORE_set_depth(),
X509_STORE_set_flags(), X509_STORE_set_purpose(),
X509_STORE_set_trust(), X509_STORE_load_locations(), and
X509_STORE_set_default_paths() return 1 on success or 0 on failure.
=head1 SEE ALSO
Copyright 2017 The OpenSSL Project Authors. All Rights Reserved.
Licensed under the OpenSSL license (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