X509_LOOKUP

Section: OpenSSL (3)
Updated: 2021-03-26
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NAME

X509_LOOKUP, X509_LOOKUP_TYPE, X509_LOOKUP_new, X509_LOOKUP_free, X509_LOOKUP_init, X509_LOOKUP_shutdown, X509_LOOKUP_set_method_data, X509_LOOKUP_get_method_data, X509_LOOKUP_ctrl, X509_LOOKUP_load_file, X509_LOOKUP_add_dir, X509_LOOKUP_get_store, X509_LOOKUP_by_subject, X509_LOOKUP_by_issuer_serial, X509_LOOKUP_by_fingerprint, X509_LOOKUP_by_alias - OpenSSL certificate lookup mechanisms

SYNOPSIS

 #include <openssl/x509_vfy.h>

 typedef x509_lookup_st X509_LOOKUP;

 typedef enum X509_LOOKUP_TYPE;

 X509_LOOKUP *X509_LOOKUP_new(X509_LOOKUP_METHOD *method);
 int X509_LOOKUP_init(X509_LOOKUP *ctx);
 int X509_LOOKUP_shutdown(X509_LOOKUP *ctx);
 void X509_LOOKUP_free(X509_LOOKUP *ctx);

 int X509_LOOKUP_set_method_data(X509_LOOKUP *ctx, void *data);
 void *X509_LOOKUP_get_method_data(const X509_LOOKUP *ctx);

 int X509_LOOKUP_ctrl(X509_LOOKUP *ctx, int cmd, const char *argc,
                      long argl, char **ret);
 int X509_LOOKUP_load_file(X509_LOOKUP *ctx, char *name, long type);
 int X509_LOOKUP_add_dir(X509_LOOKUP *ctx, char *name, long type);

 X509_STORE *X509_LOOKUP_get_store(const X509_LOOKUP *ctx);

 int X509_LOOKUP_by_subject(X509_LOOKUP *ctx, X509_LOOKUP_TYPE type,
                            X509_NAME *name, X509_OBJECT *ret);
 int X509_LOOKUP_by_issuer_serial(X509_LOOKUP *ctx, X509_LOOKUP_TYPE type,
                                  X509_NAME *name, ASN1_INTEGER *serial,
                                  X509_OBJECT *ret);
 int X509_LOOKUP_by_fingerprint(X509_LOOKUP *ctx, X509_LOOKUP_TYPE type,
                                const unsigned char *bytes, int len,
                                X509_OBJECT *ret);
 int X509_LOOKUP_by_alias(X509_LOOKUP *ctx, X509_LOOKUP_TYPE type,
                          const char *str, int len, X509_OBJECT *ret);

DESCRIPTION

The X509_LOOKUP structure holds the information needed to look up certificates and CRLs according to an associated X509_LOOKUP_METHOD(3). Multiple X509_LOOKUP instances can be added to an X509_STORE(3) to enable lookup in that store.

X509_LOOKUP_new() creates a new X509_LOOKUP using the given lookup method. It can also be created by calling X509_STORE_add_lookup(3), which will associate an X509_STORE with the lookup mechanism.

X509_LOOKUP_init() initializes the internal state and resources as needed by the given X509_LOOKUP to do its work.

X509_LOOKUP_shutdown() tears down the internal state and resources of the given X509_LOOKUP.

X509_LOOKUP_free() destructs the given X509_LOOKUP.

X509_LOOKUP_set_method_data() associates a pointer to application data to the given X509_LOOKUP.

X509_LOOKUP_get_method_data() retrieves a pointer to application data from the given X509_LOOKUP.

X509_LOOKUP_ctrl() is used to set or get additional data to or from an X509_LOOKUP structure or its associated X509_LOOKUP_METHOD(3). The arguments of the control command are passed via argc and argl, its return value via *ret. The meaning of the arguments depends on the cmd number of the control command. In general, this function is not called directly, but wrapped by a macro call, see below. The control cmds known to OpenSSL are discussed in more depth in ``Control Commands''.

X509_LOOKUP_load_file() passes a filename to be loaded immediately into the associated X509_STORE. type indicates what type of object is expected. This can only be used with a lookup using the implementation X509_LOOKUP_file(3).

X509_LOOKUP_add_dir() passes a directory specification from which certificates and CRLs are loaded on demand into the associated X509_STORE. type indicates what type of object is expected. This can only be used with a lookup using the implementation X509_LOOKUP_hash_dir(3).

X509_LOOKUP_load_file(), X509_LOOKUP_add_dir(), X509_LOOKUP_add_store(), and X509_LOOKUP_load_store() are implemented as macros that use X509_LOOKUP_ctrl().

X509_LOOKUP_by_subject(), X509_LOOKUP_by_issuer_serial(), X509_LOOKUP_by_fingerprint(), and X509_LOOKUP_by_alias() look up certificates and CRLs in the X509_STORE(3) associated with the X509_LOOKUP using different criteria, where the looked up object is stored in ret. Some of the underlying X509_LOOKUP_METHODs will also cache objects matching the criteria in the associated X509_STORE, which makes it possible to handle cases where the criteria have more than one hit.

File Types

X509_LOOKUP_load_file() and X509_LOOKUP_add_dir() take a type, which can be one of the following:

X509_FILETYPE_PEM: The file or files that are loaded are expected to be in PEM format.
X509_FILETYPE_ASN1: The file or files that are loaded are expected to be in raw DER format.
X509_FILETYPE_DEFAULT: The default certificate file or directory is used. In this case, name is ignored.

Control Commands

The X509_LOOKUP_METHODs built into OpenSSL recognise the following X509_LOOKUP_ctrl() cmds:

X509_L_FILE_LOAD: This is the command that X509_LOOKUP_load_file() uses. The filename is passed in argc, and the type in argl.
X509_L_ADD_DIR: This is the command that X509_LOOKUP_add_dir() uses. The directory specification is passed in argc, and the type in argl.
X509_L_ADD_STORE: This is the command that X509_LOOKUP_add_store() uses. The URI is passed in argc.
X509_L_LOAD_STORE: This is the command that X509_LOOKUP_load_store() uses. The URI is passed in argc.

RETURN VALUES

X509_LOOKUP_new() returns an X509_LOOKUP pointer when successful, or NULL on error.

X509_LOOKUP_init() and X509_LOOKUP_shutdown() return 1 on success, or 0 on error.

X509_LOOKUP_ctrl() returns -1 if the X509_LOOKUP doesn't have an associated X509_LOOKUP_METHOD, or 1 if the doesn't have a control function. Otherwise, it returns what the control function in the X509_LOOKUP_METHOD returns, which is usually 1 on success and 0 in error.

X509_LOOKUP_get_store() returns an X509_STORE pointer if there is one, otherwise NULL.

X509_LOOKUP_by_subject(), X509_LOOKUP_by_issuer_serial(), X509_LOOKUP_by_fingerprint(), and X509_LOOKUP_by_alias() all return 0 if there is no X509_LOOKUP_METHOD or that method doesn't implement the corresponding function. Otherwise, it returns what the corresponding function in the X509_LOOKUP_METHOD returns, which is usually 1 on success and 0 in error.

COPYRIGHT

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>.