--- /dev/null
+=pod
+
+=head1 NAME
+
+SSL_CTX_set_options, SSL_set_options, SSL_CTX_get_options, SSL_get_options - manipulate SSL engine options
+
+=head1 SYNOPSIS
+
+ #include <openssl/ssl.h>
+
+ long SSL_CTX_set_options(SSL_CTX *ctx, long options);
+ long SSL_set_options(SSL *ssl, long options);
+
+ long SSL_CTX_get_options(SSL_CTX *ctx);
+ long SSL_get_options(SSL *ssl);
+
+=head1 DESCRIPTION
+
+SSL_CTX_set_options() adds the options set via bitmask in B<options> to B<ctx>.
+Options already set before are not cleared.
+
+SSL_set_options() adds the options set via bitmask in B<options> to B<ssl>.
+Options already set before are not cleared.
+
+SSL_CTX_get_options() returns the options set for B<ctx>.
+
+SSL_get_options() returns the options set for B<ssl>.
+
+=head1 NOTES
+
+The behaviour of the SSL library can be changed by setting several options.
+The options are coded as bitmasks and can be combined by a logical B<or>
+operation (|). Options can only be added but can never be reset.
+
+During a handshake, the option settings of the SSL object used. When
+a new SSL object is created from a context using SSL_new(), the current
+option setting is copied. Changes to B<ctx> do not affect already created
+SSL objects. SSL_clear() does not affect the settings.
+
+The following B<bug workaround> options are available:
+
+=over 4
+
+=item SSL_OP_MICROSOFT_SESS_ID_BUG
+
+www.microsoft.com - when talking SSLv2, if session-id reuse is
+performed, the session-id passed back in the server-finished message
+is different from the one decided upon.
+
+=item SSL_OP_NETSCAPE_CHALLENGE_BUG
+
+Netscape-Commerce/1.12, when talking SSLv2, accepts a 32 byte
+challenge but then appears to only use 16 bytes when generating the
+encryption keys. Using 16 bytes is ok but it should be ok to use 32.
+According to the SSLv3 spec, one should use 32 bytes for the challenge
+when opperating in SSLv2/v3 compatablity mode, but as mentioned above,
+this breaks this server so 16 bytes is the way to go.
+
+=item SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG
+
+ssl3.netscape.com:443, first a connection is established with RC4-MD5.
+If it is then resumed, we end up using DES-CBC3-SHA. It should be
+RC4-MD5 according to 7.6.1.3, 'cipher_suite'.
+
+Netscape-Enterprise/2.01 (https://merchant.netscape.com) has this bug.
+It only really shows up when connecting via SSLv2/v3 then reconnecting
+via SSLv3. The cipher list changes....
+
+NEW INFORMATION. Try connecting with a cipher list of just
+DES-CBC-SHA:RC4-MD5. For some weird reason, each new connection uses
+RC4-MD5, but a re-connect tries to use DES-CBC-SHA. So netscape, when
+doing a re-connect, always takes the first cipher in the cipher list.
+
+=item SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG
+
+...
+
+=item SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER
+
+...
+
+=item SSL_OP_MSIE_SSLV2_RSA_PADDING
+
+...
+
+=item SSL_OP_SSLEAY_080_CLIENT_DH_BUG
+
+...
+
+=item SSL_OP_TLS_D5_BUG
+
+...
+
+=item SSL_OP_TLS_BLOCK_PADDING_BUG
+
+...
+
+=item SSL_OP_TLS_ROLLBACK_BUG
+
+Disable version rollback attack detection.
+
+During the client key exchange, the client must send the same information
+about acceptable SSL/TLS protocol levels as during the first hello. Some
+clients violate this rule by adapting to the server's answer. (Example:
+the client sends a SSLv2 hello and accepts up to SSLv3.1=TLSv1, the server
+only understands up to SSLv3. In this case the client must still use the
+same SSLv3.1=TLSv1 announcement. Some clients step down to SSLv3 with respect
+to the server's answer and violate the version rollback protection.)
+
+=item SSL_OP_ALL
+
+All of the above bug workarounds.
+
+=back
+
+It is save and recommended to use SSL_OP_ALL to enable the bug workaround
+options.
+
+The following B<modifying> options are available:
+
+=over 4
+
+=item SSL_OP_SINGLE_DH_USE
+
+Always create a new key when using temporary DH parameters.
+
+=item SSL_OP_EPHEMERAL_RSA
+
+Also use the temporary RSA key when doing RSA operations.
+
+=item SSL_OP_PKCS1_CHECK_1
+
+...
+
+=item SSL_OP_PKCS1_CHECK_2
+
+...
+
+=item SSL_OP_NETSCAPE_CA_DN_BUG
+
+If we accept a netscape connection, demand a client cert, have a
+non-self-sighed CA which does not have it's CA in netscape, and the
+browser has a cert, it will crash/hang. Works for 3.x and 4.xbeta
+
+=item SSL_OP_NON_EXPORT_FIRST
+
+On servers try to use non-export (stronger) ciphers first. This option does
+not work under all circumstances (in the code it is declared "broken").
+
+=item SSL_OP_NETSCAPE_DEMO_CIPHER_CHANGE_BUG
+
+...
+
+=item SSL_OP_NO_SSLv2
+
+Do not use the SSLv2 protocol.
+
+=item SSL_OP_NO_SSLv3
+
+Do not use the SSLv3 protocol.
+
+=item SSL_OP_NO_TLSv1
+
+Do not use the TLSv1 protocol.
+
+=back
+
+=head1 RETURN VALUES
+
+SSL_CTX_set_options() and SSL_set_options() return the new options bitmask
+after adding B<options>.
+
+SSL_CTX_get_options() and SSL_get_options() return the current bitmask.
+
+=head1 SEE ALSO
+
+L<ssl(3)|ssl(3)>, L<SSL_new(3)|SSL_new(3)>, L<SSL_clear(3)|SSL_clear(3)>
+
+=head1 HISTORY
+
+SSL_OP_TLS_ROLLBACK_BUG has been added in OpenSSL 0.9.6.
+
+=cut
projects / openssl.git / commitdiff