175 lines
6.6 KiB
Plaintext
175 lines
6.6 KiB
Plaintext
=pod
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=head1 NAME
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SSL_CTX_new,
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SSLv23_method, SSLv23_server_method, SSLv23_client_method,
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TLSv1_2_method, TLSv1_2_server_method, TLSv1_2_client_method,
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TLSv1_1_method, TLSv1_1_server_method, TLSv1_1_client_method,
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TLSv1_method, TLSv1_server_method, TLSv1_client_method,
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SSLv3_method, SSLv3_server_method, SSLv3_client_method,
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SSLv2_method, SSLv2_server_method, SSLv2_client_method,
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DTLS_method, DTLS_server_method, DTLS_client_method,
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DTLSv1_2_method, DTLSv1_2_server_method, DTLSv1_2_client_method,
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DTLSv1_method, DTLSv1_server_method, DTLSv1_client_method -
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create a new SSL_CTX object as framework for TLS/SSL enabled functions
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=head1 SYNOPSIS
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#include <openssl/ssl.h>
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SSL_CTX *SSL_CTX_new(const SSL_METHOD *method);
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const SSL_METHOD *SSLv23_method(void);
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const SSL_METHOD *SSLv23_server_method(void);
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const SSL_METHOD *SSLv23_client_method(void);
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const SSL_METHOD *TLSv1_2_method(void);
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const SSL_METHOD *TLSv1_2_server_method(void);
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const SSL_METHOD *TLSv1_2_client_method(void);
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const SSL_METHOD *TLSv1_1_method(void);
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const SSL_METHOD *TLSv1_1_server_method(void);
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const SSL_METHOD *TLSv1_1_client_method(void);
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const SSL_METHOD *TLSv1_method(void);
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const SSL_METHOD *TLSv1_server_method(void);
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const SSL_METHOD *TLSv1_client_method(void);
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#ifndef OPENSSL_NO_SSL3_METHOD
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const SSL_METHOD *SSLv3_method(void);
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const SSL_METHOD *SSLv3_server_method(void);
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const SSL_METHOD *SSLv3_client_method(void);
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#endif
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#ifndef OPENSSL_NO_SSL2
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const SSL_METHOD *SSLv2_method(void);
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const SSL_METHOD *SSLv2_server_method(void);
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const SSL_METHOD *SSLv2_client_method(void);
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#endif
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const SSL_METHOD *DTLS_method(void);
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const SSL_METHOD *DTLS_server_method(void);
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const SSL_METHOD *DTLS_client_method(void);
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const SSL_METHOD *DTLSv1_2_method(void);
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const SSL_METHOD *DTLSv1_2_server_method(void);
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const SSL_METHOD *DTLSv1_2_client_method(void);
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const SSL_METHOD *DTLSv1_method(void);
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const SSL_METHOD *DTLSv1_server_method(void);
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const SSL_METHOD *DTLSv1_client_method(void);
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=head1 DESCRIPTION
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SSL_CTX_new() creates a new B<SSL_CTX> object as framework to establish
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TLS/SSL enabled connections.
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=head1 NOTES
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The SSL_CTX object uses B<method> as connection method. The methods exist
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in a generic type (for client and server use), a server only type, and a
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client only type. B<method> can be of the following types:
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=over 4
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=item SSLv23_method(), SSLv23_server_method(), SSLv23_client_method()
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These are the general-purpose I<version-flexible> SSL/TLS methods.
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The actual protocol version used will be negotiated to the highest version
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mutually supported by the client and the server.
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The supported protocols are SSLv2, SSLv3, TLSv1, TLSv1.1 and TLSv1.2.
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Most applications should use these method, and avoid the version specific
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methods described below.
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The list of protocols available can be further limited using the
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B<SSL_OP_NO_SSLv2>, B<SSL_OP_NO_SSLv3>, B<SSL_OP_NO_TLSv1>,
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B<SSL_OP_NO_TLSv1_1> and B<SSL_OP_NO_TLSv1_2> options of the
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L<SSL_CTX_set_options(3)> or L<SSL_set_options(3)> functions.
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Clients should avoid creating "holes" in the set of protocols they support,
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when disabling a protocol, make sure that you also disable either all previous
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or all subsequent protocol versions.
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In clients, when a protocol version is disabled without disabling I<all>
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previous protocol versions, the effect is to also disable all subsequent
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protocol versions.
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The SSLv2 and SSLv3 protocols are deprecated and should generally not be used.
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Applications should typically use L<SSL_CTX_set_options(3)> in combination with
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the B<SSL_OP_NO_SSLv3> flag to disable negotiation of SSLv3 via the above
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I<version-flexible> SSL/TLS methods.
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The B<SSL_OP_NO_SSLv2> option is set by default, and would need to be cleared
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via L<SSL_CTX_clear_options(3)> in order to enable negotiation of SSLv2.
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=item TLSv1_2_method(), TLSv1_2_server_method(), TLSv1_2_client_method()
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A TLS/SSL connection established with these methods will only understand the
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TLSv1.2 protocol. A client will send out TLSv1.2 client hello messages and
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will also indicate that it only understand TLSv1.2. A server will only
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understand TLSv1.2 client hello messages.
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=item TLSv1_1_method(), TLSv1_1_server_method(), TLSv1_1_client_method()
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A TLS/SSL connection established with these methods will only understand the
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TLSv1.1 protocol. A client will send out TLSv1.1 client hello messages and
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will also indicate that it only understand TLSv1.1. A server will only
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understand TLSv1.1 client hello messages.
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=item TLSv1_method(), TLSv1_server_method(), TLSv1_client_method()
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A TLS/SSL connection established with these methods will only understand the
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TLSv1 protocol. A client will send out TLSv1 client hello messages and will
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indicate that it only understands TLSv1. A server will only understand TLSv1
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client hello messages.
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=item SSLv3_method(), SSLv3_server_method(), SSLv3_client_method()
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A TLS/SSL connection established with these methods will only understand the
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SSLv3 protocol. A client will send out SSLv3 client hello messages and will
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indicate that it only understands SSLv3. A server will only understand SSLv3
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client hello messages. The SSLv3 protocol is deprecated and should not be
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used.
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=item SSLv2_method(), SSLv2_server_method(), SSLv2_client_method()
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A TLS/SSL connection established with these methods will only understand the
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SSLv2 protocol. A client will send out SSLv2 client hello messages and will
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also indicate that it only understand SSLv2. A server will only understand
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SSLv2 client hello messages. The SSLv2 protocol offers little to no security
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and should not be used.
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As of OpenSSL 1.0.2g, EXPORT ciphers and 56-bit DES are no longer available
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with SSLv2.
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=item DTLS_method(), DTLS_server_method(), DTLS_client_method()
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These are the version-flexible DTLS methods.
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=item DTLSv1_2_method(), DTLSv1_2_server_method(), DTLSv1_2_client_method()
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These are the version-specific methods for DTLSv1.2.
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=item DTLSv1_method(), DTLSv1_server_method(), DTLSv1_client_method()
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These are the version-specific methods for DTLSv1.
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=back
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SSL_CTX_new() initializes the list of ciphers, the session cache setting, the
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callbacks, the keys and certificates and the options to its default values.
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=head1 RETURN VALUES
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The following return values can occur:
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=over 4
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=item NULL
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The creation of a new SSL_CTX object failed. Check the error stack to find out
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the reason.
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=item Pointer to an SSL_CTX object
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The return value points to an allocated SSL_CTX object.
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=back
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=head1 SEE ALSO
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L<SSL_CTX_set_options(3)>, L<SSL_CTX_clear_options(3)>, L<SSL_set_options(3)>,
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L<SSL_CTX_free(3)|SSL_CTX_free(3)>, L<SSL_accept(3)|SSL_accept(3)>,
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L<ssl(3)|ssl(3)>, L<SSL_set_connect_state(3)|SSL_set_connect_state(3)>
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=cut
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