SSL_CTX_set_options() and SSL_set_options() affect the (external)
protocol behaviour of the SSL library. The (internal) behaviour of
the API can be changed by using the similar
-L<SSL_CTX_set_mode(3)|SSL_CTX_set_mode(3)> and SSL_set_mode() functions.
+L<SSL_CTX_set_mode(3)> and SSL_set_mode() functions.
During a handshake, the option settings of the SSL object are used. When
a new SSL object is created from a context using SSL_new(), the current
=over 4
-=item SSL_OP_MICROSOFT_SESS_ID_BUG
-
-As of OpenSSL 1.0.0 this option has no effect.
-
-=item SSL_OP_NETSCAPE_CHALLENGE_BUG
-
-As of OpenSSL 1.0.0 this option has no effect.
-
-=item SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG
-
-As of OpenSSL 0.9.8q and 1.0.0c, this option has no effect.
-
=item SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG
...
...
-=item SSL_OP_TLS_BLOCK_PADDING_BUG
-
-...
-
=item SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS
Disables a countermeasure against a SSL 3.0/TLS 1.0 protocol
=item SSL_OP_SINGLE_DH_USE
Always create a new key when using temporary/ephemeral DH parameters
-(see L<SSL_CTX_set_tmp_dh_callback(3)|SSL_CTX_set_tmp_dh_callback(3)>).
+(see L<SSL_CTX_set_tmp_dh_callback(3)>).
This option must be used to prevent small subgroup attacks, when
the DH parameters were not generated using "strong" primes
-(e.g. when using DSA-parameters, see L<dhparam(1)|dhparam(1)>).
+(e.g. when using DSA-parameters, see L<dhparam(1)>).
If "strong" primes were used, it is not strictly necessary to generate
a new DH key during each handshake but it is also recommended.
B<SSL_OP_SINGLE_DH_USE> should therefore be enabled whenever
=item SSL_OP_EPHEMERAL_RSA
-Always use ephemeral (temporary) RSA key when doing RSA operations
-(see L<SSL_CTX_set_tmp_rsa_callback(3)|SSL_CTX_set_tmp_rsa_callback(3)>).
-According to the specifications this is only done, when a RSA key
-can only be used for signature operations (namely under export ciphers
-with restricted RSA keylength). By setting this option, ephemeral
-RSA keys are always used. This option breaks compatibility with the
-SSL/TLS specifications and may lead to interoperability problems with
-clients and should therefore never be used. Ciphers with DHE (ephemeral
-Diffie-Hellman) key exchange should be used instead.
+This option is no longer implemented and is treated as no op.
=item SSL_OP_CIPHER_SERVER_PREFERENCE
...
-=item SSL_OP_NETSCAPE_CA_DN_BUG
-If we accept a netscape connection, demand a client cert, have a
-non-self-signed CA which does not have its CA in netscape, and the
-browser has a cert, it will crash/hang. Works for 3.x and 4.xbeta
-
-=item SSL_OP_NETSCAPE_DEMO_CIPHER_CHANGE_BUG
-
-...
=item SSL_OP_NO_SSLv2
=head1 SECURE RENEGOTIATION
-OpenSSL 0.9.8m and later always attempts to use secure renegotiation as
+OpenSSL always attempts to use secure renegotiation as
described in RFC5746. This counters the prefix attack described in
CVE-2009-3555 and elsewhere.
If the option B<SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION> is set then
renegotiation B<always> succeeds.
-B<NB:> a bug in OpenSSL clients earlier than 0.9.8m (all of which are
-unpatched) will result in the connection hanging if it receives a
-B<no_renegotiation> alert. OpenSSL versions 0.9.8m and later will regard
-a B<no_renegotiation> alert as fatal and respond with a fatal
-B<handshake_failure> alert. This is because the OpenSSL API currently has
-no provision to indicate to an application that a renegotiation attempt
-was refused.
-
=head2 Patched OpenSSL client and unpatched server.
If the option B<SSL_OP_LEGACY_SERVER_CONNECT> or
=head1 SEE ALSO
-L<ssl(3)|ssl(3)>, L<SSL_new(3)|SSL_new(3)>, L<SSL_clear(3)|SSL_clear(3)>,
-L<SSL_CTX_set_tmp_dh_callback(3)|SSL_CTX_set_tmp_dh_callback(3)>,
-L<SSL_CTX_set_tmp_rsa_callback(3)|SSL_CTX_set_tmp_rsa_callback(3)>,
-L<dhparam(1)|dhparam(1)>
+L<ssl(3)>, L<SSL_new(3)>, L<SSL_clear(3)>,
+L<SSL_CTX_set_tmp_dh_callback(3)>,
+L<SSL_CTX_set_tmp_rsa_callback(3)>,
+L<dhparam(1)>
=head1 HISTORY
-B<SSL_OP_CIPHER_SERVER_PREFERENCE> and
-B<SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION> have been added in
-OpenSSL 0.9.7.
-
-B<SSL_OP_TLS_ROLLBACK_BUG> has been added in OpenSSL 0.9.6 and was automatically
-enabled with B<SSL_OP_ALL>. As of 0.9.7, it is no longer included in B<SSL_OP_ALL>
-and must be explicitly set.
-
-B<SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS> has been added in OpenSSL 0.9.6e.
-Versions up to OpenSSL 0.9.6c do not include the countermeasure that
-can be disabled with this option (in OpenSSL 0.9.6d, it was always
-enabled).
-
-SSL_CTX_clear_options() and SSL_clear_options() were first added in OpenSSL
-0.9.8m.
-
-B<SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION>, B<SSL_OP_LEGACY_SERVER_CONNECT>
-and the function SSL_get_secure_renegotiation_support() were first added in
-OpenSSL 0.9.8m.
+The attempt to always try to use secure renegotiation was added in
+Openssl 0.9.8m.
=cut
projects / openssl.git / blobdiff