- NAME
- SYNOPSIS
- DESCRIPTION
  - File Types
  - Control Commands
- RETURN VALUES
- SEE ALSO
- COPYRIGHT

# 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.

# SEE ALSO

X509_LOOKUP_METHOD(3), X509_STORE(3)

# COPYRIGHT

Copyright 2020 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.