=encoding utf-8

=head1 NAME

ngx_stream_ssl_module - Module ngx_stream_ssl_module




=head1



The C<ngx_stream_ssl_module> module (1.9.0)
provides the necessary support for a stream proxy server to work with
the SSLE<sol>TLS protocol.
This module is not built by default, it should be enabled with the
C<--with-stream_ssl_module>
configuration parameter.




=head1 Example Configuration



To reduce the processor load, it is recommended to

=over




=item *

set the number of
L<worker processes|ngx_core_module>
equal to the number of processors,



=item *

enable the shared session cache,



=item *

disable the built-in session cache,



=item *

and possibly increase the session lifetime
(by default, 5 minutes):



=back




    
    <emphasis>worker_processes auto;</emphasis>
    
    stream {
    
        ...
    
        server {
            listen              12345 ssl;
    
            ssl_protocols       TLSv1 TLSv1.1 TLSv1.2;
            ssl_ciphers         AES128-SHA:AES256-SHA:RC4-SHA:DES-CBC3-SHA:RC4-MD5;
            ssl_certificate     /usr/local/nginx/conf/cert.pem;
            ssl_certificate_key /usr/local/nginx/conf/cert.key;
            <emphasis>ssl_session_cache   shared:SSL:10m;</emphasis>
            <emphasis>ssl_session_timeout 10m;</emphasis>
    
            ...
        }






=head1 Directives

=head2 ssl_alpn


B<syntax:> ssl_alpn I<I<C<protocol>> ...>



B<context:> I<stream>


B<context:> I<server>



This directive appeared in version 1.21.4.





Specifies the list of supported
L<ALPN|https://datatracker.ietf.org/doc/html/rfc7301> protocols.
One of the protocols must be
negotiated if the client uses ALPN:

    
    map $ssl_alpn_protocol $proxy {
        h2                127.0.0.1:8001;
        http/1.1          127.0.0.1:8002;
    }
    
    server {
        listen      12346;
        proxy_pass  $proxy;
        ssl_alpn    h2 http/1.1;
    }









=head2 ssl_certificate


B<syntax:> ssl_certificate I<I<C<file>>>



B<context:> I<stream>


B<context:> I<server>





Specifies a I<C<file>> with the certificate in the PEM format
for the given server.
If intermediate certificates should be specified in addition to a primary
certificate, they should be specified in the same file in the following
order: the primary certificate comes first, then the intermediate certificates.
A secret key in the PEM format may be placed in the same file.





Since version 1.11.0,
this directive can be specified multiple times
to load certificates of different types, for example, RSA and ECDSA:

    
    server {
        listen              12345 ssl;
    
        ssl_certificate     example.com.rsa.crt;
        ssl_certificate_key example.com.rsa.key;
    
        ssl_certificate     example.com.ecdsa.crt;
        ssl_certificate_key example.com.ecdsa.key;
    
        ...
    }



B<NOTE>

Only OpenSSL 1.0.2 or higher supports separate certificate chains
for different certificates.
With older versions, only one certificate chain can be used.






Since version 1.15.9, variables can be used in the I<C<file>> name
when using OpenSSL 1.0.2 or higher:

    
    ssl_certificate     $ssl_server_name.crt;
    ssl_certificate_key $ssl_server_name.key;


Note that using variables implies that
a certificate will be loaded for each SSL handshake,
and this may have a negative impact on performance.





The value
C<data>:I<C<$variable>>
can be specified instead of the I<C<file>> (1.15.10),
which loads a certificate from a variable without using intermediate files.
Note that inappropriate use of this syntax may have its security implications,
such as writing secret key data to
L<error log|ngx_core_module>.







=head2 ssl_certificate_key


B<syntax:> ssl_certificate_key I<I<C<file>>>



B<context:> I<stream>


B<context:> I<server>





Specifies a I<C<file>> with the secret key in the PEM format
for the given server.





The value
C<engine>:I<C<name>>:I<C<id>>
can be specified instead of the I<C<file>>,
which loads a secret key with a specified I<C<id>>
from the OpenSSL engine I<C<name>>.





The value
C<data>:I<C<$variable>>
can be specified instead of the I<C<file>> (1.15.10),
which loads a secret key from a variable without using intermediate files.
Note that inappropriate use of this syntax may have its security implications,
such as writing secret key data to
L<error log|ngx_core_module>.





Since version 1.15.9, variables can be used in the I<C<file>> name
when using OpenSSL 1.0.2 or higher.







=head2 ssl_ciphers


B<syntax:> ssl_ciphers I<I<C<ciphers>>>


B<default:> I<HIGH:!aNULL:!MD5>


B<context:> I<stream>


B<context:> I<server>





Specifies the enabled ciphers.
The ciphers are specified in the format understood by the
OpenSSL library, for example:

    
    ssl_ciphers ALL:!aNULL:!EXPORT56:RC4+RSA:+HIGH:+MEDIUM:+LOW:+SSLv2:+EXP;







The full list can be viewed using the
“C<openssl ciphers>” command.







=head2 ssl_client_certificate


B<syntax:> ssl_client_certificate I<I<C<file>>>



B<context:> I<stream>


B<context:> I<server>



This directive appeared in version 1.11.8.





Specifies a I<C<file>> with trusted CA certificates in the PEM format
used to verify client certificates.





The list of certificates will be sent to clients.
If this is not desired, the L</ssl_trusted_certificate>
directive can be used.







=head2 ssl_conf_command


B<syntax:> ssl_conf_command I<I<C<command>> ...>



B<context:> I<stream>


B<context:> I<server>



This directive appeared in version 1.19.4.





Sets arbitrary OpenSSL configuration
L<commands|https://www.openssl.org/docs/man1.1.1/man3/SSL_CONF_cmd.html>.

B<NOTE>

The directive is supported when using OpenSSL 1.0.2 or higher.






Several C<ssl_conf_command> directives
can be specified on the same level:

    
    ssl_conf_command Options PrioritizeChaCha;
    ssl_conf_command Ciphersuites TLS_CHACHA20_POLY1305_SHA256;


These directives are inherited from the previous configuration level
if and only if there are no C<ssl_conf_command> directives
defined on the current level.






B<NOTE>

Note that configuring OpenSSL directly
might result in unexpected behavior.








=head2 ssl_crl


B<syntax:> ssl_crl I<I<C<file>>>



B<context:> I<stream>


B<context:> I<server>



This directive appeared in version 1.11.8.





Specifies a I<C<file>> with revoked certificates (CRL)
in the PEM format used to verify
client certificates.







=head2 ssl_dhparam


B<syntax:> ssl_dhparam I<I<C<file>>>



B<context:> I<stream>


B<context:> I<server>





Specifies a I<C<file>> with DH parameters for DHE ciphers.





By default no parameters are set,
and therefore DHE ciphers will not be used.

B<NOTE>

Prior to version 1.11.0, builtin parameters were used by default.








=head2 ssl_ecdh_curve


B<syntax:> ssl_ecdh_curve I<I<C<curve>>>


B<default:> I<auto>


B<context:> I<stream>


B<context:> I<server>





Specifies a I<C<curve>> for ECDHE ciphers.





When using OpenSSL 1.0.2 or higher,
it is possible to specify multiple curves (1.11.0), for example:

    
    ssl_ecdh_curve prime256v1:secp384r1;







The special value C<auto> (1.11.0) instructs nginx to use
a list built into the OpenSSL library when using OpenSSL 1.0.2 or higher,
or C<prime256v1> with older versions.






B<NOTE>

Prior to version 1.11.0,
the C<prime256v1> curve was used by default.







B<NOTE>

When using OpenSSL 1.0.2 or higher,
this directive sets the list of curves supported by the server.
Thus, in order for ECDSA certificates to work,
it is important to include the curves used in the certificates.








=head2 ssl_handshake_timeout


B<syntax:> ssl_handshake_timeout I<I<C<time>>>


B<default:> I<60s>


B<context:> I<stream>


B<context:> I<server>





Specifies a timeout for the SSL handshake to complete.







=head2 ssl_password_file


B<syntax:> ssl_password_file I<I<C<file>>>



B<context:> I<stream>


B<context:> I<server>





Specifies a I<C<file>> with passphrases for
secret keys
where each passphrase is specified on a separate line.
Passphrases are tried in turn when loading the key.





Example:

    
    stream {
        ssl_password_file /etc/keys/global.pass;
        ...
    
        server {
            listen 127.0.0.1:12345;
            ssl_certificate_key /etc/keys/first.key;
        }
    
        server {
            listen 127.0.0.1:12346;
    
            # named pipe can also be used instead of a file
            ssl_password_file /etc/keys/fifo;
            ssl_certificate_key /etc/keys/second.key;
        }
    }









=head2 ssl_prefer_server_ciphers


B<syntax:> ssl_prefer_server_ciphers I<C<on> E<verbar> C<off>>


B<default:> I<off>


B<context:> I<stream>


B<context:> I<server>





Specifies that server ciphers should be preferred over client ciphers
when the SSLv3 and TLS protocols are used.







=head2 ssl_protocols


B<syntax:> ssl_protocols I<
    [C<SSLv2>]
    [C<SSLv3>]
    [C<TLSv1>]
    [C<TLSv1.1>]
    [C<TLSv1.2>]
    [C<TLSv1.3>]>


B<default:> I<TLSv1 TLSv1.1 TLSv1.2>


B<context:> I<stream>


B<context:> I<server>





Enables the specified protocols.

B<NOTE>

The C<TLSv1.1> and C<TLSv1.2> parameters work
only when OpenSSL 1.0.1 or higher is used.


B<NOTE>

The C<TLSv1.3> parameter (1.13.0) works only when
OpenSSL 1.1.1 or higher is used.








=head2 ssl_session_cache


B<syntax:> ssl_session_cache I<
    C<off> E<verbar>
    C<none> E<verbar>
    [C<builtin>[:I<C<size>>]]
    [C<shared>:I<C<name>>:I<C<size>>]>


B<default:> I<none>


B<context:> I<stream>


B<context:> I<server>





Sets the types and sizes of caches that store session parameters.
A cache can be of any of the following types:

=over



=item C<off>




the use of a session cache is strictly prohibited:
nginx explicitly tells a client that sessions may not be reused.



=item C<none>




the use of a session cache is gently disallowed:
nginx tells a client that sessions may be reused, but does not
actually store session parameters in the cache.



=item C<builtin>




a cache built in OpenSSL; used by one worker process only.
The cache size is specified in sessions.
If size is not given, it is equal to 20480 sessions.
Use of the built-in cache can cause memory fragmentation.



=item C<shared>




a cache shared between all worker processes.
The cache size is specified in bytes; one megabyte can store
about 4000 sessions.
Each shared cache should have an arbitrary name.
A cache with the same name can be used in several
servers.




=back







Both cache types can be used simultaneously, for example:

    
    ssl_session_cache builtin:1000 shared:SSL:10m;


but using only shared cache without the built-in cache should
be more efficient.







=head2 ssl_session_ticket_key


B<syntax:> ssl_session_ticket_key I<I<C<file>>>



B<context:> I<stream>


B<context:> I<server>





Sets a I<C<file>> with the secret key used to encrypt
and decrypt TLS session tickets.
The directive is necessary if the same key has to be shared between
multiple servers.
By default, a randomly generated key is used.





If several keys are specified, only the first key is
used to encrypt TLS session tickets.
This allows configuring key rotation, for example:

    
    ssl_session_ticket_key current.key;
    ssl_session_ticket_key previous.key;







The I<C<file>> must contain 80 or 48 bytes
of random data and can be created using the following command:

    
    openssl rand 80 > ticket.key


Depending on the file size either AES256 (for 80-byte keys, 1.11.8)
or AES128 (for 48-byte keys) is used for encryption.







=head2 ssl_session_tickets


B<syntax:> ssl_session_tickets I<C<on> E<verbar> C<off>>


B<default:> I<on>


B<context:> I<stream>


B<context:> I<server>





Enables or disables session resumption through
L<TLS session tickets|https://datatracker.ietf.org/doc/html/rfc5077>.







=head2 ssl_session_timeout


B<syntax:> ssl_session_timeout I<I<C<time>>>


B<default:> I<5m>


B<context:> I<stream>


B<context:> I<server>





Specifies a time during which a client may reuse the
session parameters.







=head2 ssl_trusted_certificate


B<syntax:> ssl_trusted_certificate I<I<C<file>>>



B<context:> I<stream>


B<context:> I<server>



This directive appeared in version 1.11.8.





Specifies a I<C<file>> with trusted CA certificates in the PEM format
used to verify client certificates.





In contrast to the certificate set by L</ssl_client_certificate>,
the list of these certificates will not be sent to clients.







=head2 ssl_verify_client


B<syntax:> ssl_verify_client I<
    C<on> E<verbar> C<off> E<verbar>
    C<optional> E<verbar> C<optional_no_ca>>


B<default:> I<off>


B<context:> I<stream>


B<context:> I<server>



This directive appeared in version 1.11.8.





Enables verification of client certificates.
The verification result is stored in the
$ssl_client_verify variable.
If an error has occurred during the client certificate verification
or a client has not presented the required certificate,
the connection is closed.





The C<optional> parameter requests the client
certificate and verifies it if the certificate is present.





The C<optional_no_ca> parameter
requests the client
certificate but does not require it to be signed by a trusted CA certificate.
This is intended for the use in cases when a service that is external to nginx
performs the actual certificate verification.
The contents of the certificate is accessible through the
$ssl_client_cert variable.







=head2 ssl_verify_depth


B<syntax:> ssl_verify_depth I<I<C<number>>>


B<default:> I<1>


B<context:> I<stream>


B<context:> I<server>



This directive appeared in version 1.11.8.





Sets the verification depth in the client certificates chain.







=head1 Embedded Variables



The C<ngx_stream_ssl_module> module supports variables
since 1.11.2.

=over



=item C<$ssl_alpn_protocol>




returns the protocol selected by ALPN during the SSL handshake,
or an empty string otherwise (1.21.4);



=item C<$ssl_cipher>




returns the name of the cipher used
for an established SSL connection;



=item C<$ssl_ciphers>




returns the list of ciphers supported by the client (1.11.7).
Known ciphers are listed by names, unknown are shown in hexadecimal,
for example:

    
    AES128-SHA:AES256-SHA:0x00ff



B<NOTE>

The variable is fully supported only when using OpenSSL version 1.0.2 or higher.
With older versions, the variable is available
only for new sessions and lists only known ciphers.




=item C<$ssl_client_cert>




returns the client certificate in the PEM format
for an established SSL connection, with each line except the first
prepended with the tab character (1.11.8);



=item C<$ssl_client_fingerprint>




returns the SHA1 fingerprint of the client certificate
for an established SSL connection (1.11.8);



=item C<$ssl_client_i_dn>




returns the “issuer DN” string of the client certificate
for an established SSL connection according to
L<RFC 2253|https://datatracker.ietf.org/doc/html/rfc2253> (1.11.8);



=item C<$ssl_client_raw_cert>





returns the client certificate in the PEM format
for an established SSL connection (1.11.8);



=item C<$ssl_client_s_dn>




returns the “subject DN” string of the client certificate
for an established SSL connection according to
L<RFC 2253|https://datatracker.ietf.org/doc/html/rfc2253> (1.11.8);



=item C<$ssl_client_serial>




returns the serial number of the client certificate
for an established SSL connection (1.11.8);



=item C<$ssl_client_v_end>




returns the end date of the client certificate (1.11.8);



=item C<$ssl_client_v_remain>




returns the number of days
until the client certificate expires (1.11.8);



=item C<$ssl_client_v_start>




returns the start date of the client certificate (1.11.8);



=item C<$ssl_client_verify>




returns the result of client certificate verification (1.11.8):
“C<SUCCESS>”, “C<FAILED:>I<C<reason>>”,
and “C<NONE>” if a certificate was not present;



=item C<$ssl_curve>




returns the negotiated curve used for
SSL handshake key exchange process (1.21.5).
Known curves are listed by names, unknown are shown in hexadecimal,
for example:

    
    prime256v1



B<NOTE>

The variable is supported only when using OpenSSL version 3.0 or higher.
With older versions, the variable value will be an empty string.




=item C<$ssl_curves>




returns the list of curves supported by the client (1.11.7).
Known curves are listed by names, unknown are shown in hexadecimal,
for example:

    
    0x001d:prime256v1:secp521r1:secp384r1



B<NOTE>

The variable is supported only when using OpenSSL version 1.0.2 or higher.
With older versions, the variable value will be an empty string.


B<NOTE>

The variable is available only for new sessions.




=item C<$ssl_protocol>




returns the protocol of an established SSL connection;



=item C<$ssl_server_name>




returns the server name requested through
L<SNI|http://en.wikipedia.org/wiki/Server_Name_Indication>;



=item C<$ssl_session_id>




returns the session identifier of an established SSL connection;



=item C<$ssl_session_reused>




returns “C<r>” if an SSL session was reused,
or “C<.>” otherwise.




=back