Cryptography and SSL/TLS Toolkit



SSL_CTX_get0_param, SSL_get0_param, SSL_CTX_set1_param, SSL_set1_param, SSL_CTX_set_purpose, SSL_CTX_set_trust, SSL_set_purpose, SSL_set_trust - get and set verification parameters


 #include <openssl/ssl.h>

 X509_VERIFY_PARAM *SSL_CTX_get0_param(SSL_CTX *ctx);
 X509_VERIFY_PARAM *SSL_get0_param(SSL *ssl);
 int SSL_CTX_set1_param(SSL_CTX *ctx, X509_VERIFY_PARAM *vpm);
 int SSL_set1_param(SSL *ssl, X509_VERIFY_PARAM *vpm);

 int SSL_CTX_set_purpose(SSL_CTX *ctx, int purpose);
 int SSL_set_purpose(SSL *ssl, int purpose);

 int SSL_CTX_set_trust(SSL_CTX *ctx, int trust);
 int SSL_set_trust(SSL *ssl, int trust);


SSL_CTX_get0_param() and SSL_get0_param() retrieve an internal pointer to the verification parameters for ctx or ssl respectively. The returned pointer must not be freed by the calling application.

SSL_CTX_set1_param() and SSL_set1_param() set the verification parameters to vpm for ctx or ssl.

The functions SSL_CTX_set_purpose() and SSL_set_purpose() are shorthands which set the purpose parameter on the verification parameters object. These functions are equivalent to calling X509_VERIFY_PARAM_set_purpose() directly.

The functions SSL_CTX_set_trust() and SSL_set_trust() are similarly shorthands which set the trust parameter on the verification parameters object. These functions are equivalent to calling X509_VERIFY_PARAM_set_trust() directly.


Typically parameters are retrieved from an SSL_CTX or SSL structure using SSL_CTX_get0_param() or SSL_get0_param() and an application modifies them to suit its needs: for example to add a hostname check.


SSL_CTX_get0_param() and SSL_get0_param() return a pointer to an X509_VERIFY_PARAM structure.

SSL_CTX_set1_param(), SSL_set1_param(), SSL_CTX_set_purpose(), SSL_set_purpose(), SSL_CTX_set_trust() and SSL_set_trust() return 1 for success and 0 for failure.


Check hostname matches "" in peer certificate:

 X509_VERIFY_PARAM *vpm = SSL_get0_param(ssl);
 X509_VERIFY_PARAM_set1_host(vpm, "", 0);


ssl(7), X509_VERIFY_PARAM_set_flags(3)


These functions were added in OpenSSL 1.0.2.

Copyright 2015-2022 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