SSL_GET_PEER_CERTIFICATE(3)                           Library Functions Manual

NAME
     SSL_get_peer_certificate - get the X509 certificate of the peer

SYNOPSIS
     #include <openssl/ssl.h>

     X509 *
     SSL_get_peer_certificate(const SSL *ssl);

DESCRIPTION
     SSL_get_peer_certificate() returns a pointer to the X509 certificate the
     peer presented.  If the peer did not present a certificate, NULL is
     returned.

     Due to the protocol definition, a TLS/SSL server will always send a
     certificate, if present.  A client will only send a certificate when
     explicitly requested to do so by the server (see SSL_CTX_set_verify(3)).
     If an anonymous cipher is used, no certificates are sent.

     That a certificate is returned does not indicate information about the
     verification state.  Use SSL_get_verify_result(3) to check the
     verification state.

     The reference count of the X509 object is incremented by one, so that it
     will not be destroyed when the session containing the peer certificate is
     freed.  The X509 object must be explicitly freed using X509_free(3).

RETURN VALUES
     The following return values can occur:

     NULL    No certificate was presented by the peer or no connection was
             established.

     Pointer to an X509 certificate
             The return value points to the certificate presented by the peer.

SEE ALSO
     ssl(3), SSL_CTX_set_verify(3), SSL_get0_peername(3),
     SSL_get_verify_result(3)

HISTORY
     SSL_get_peer_certificate() appeared in SSLeay 0.4 or earlier and has been
     available since OpenBSD 2.4.

Linux 6.8.7-arch1-1              June 26, 2021             Linux 6.8.7-arch1-1