	RSA BSAFE SSL-C	Security protocol components for C
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Option Codes

This section details the SSL_OP options that control the behavior of the protocol implementation. Pass SSL_OP_ALL as the parameter to SSL_CTX_set_options() to enable maximum bug-compatibility mode (that is, maximum interoperability).

Defines
#define	SSL_OP_MICROSOFT_SESS_ID_BUG
	Indicates a Microsoft SSLv2 session identifier reuse error. More...
#define	SSL_OP_NETSCAPE_CHALLENGE_BUG
	Indicates a Netscape SSLv2 challenge length error. More...
#define	SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG
	Indicates a Netscape SSLv3 changing reused cipher error. More...
#define	SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG
	Indicates an SSLv2 session identifier reuse certificate type error. More...
#define	SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER
	Indicates a large SSLv3 packet error. More...
#define	SSL_OP_MSIE_SSLV2_RSA_PADDING
	Indicates Microsoft SSLv2 rollback attacks on SSLv3 clients. More...
#define	SSL_OP_SSLEAY_080_CLIENT_DH_BUG
	Indicates an SSLeay version 0.8.0 Diffie-Hellman encoding error. More...
#define	SSL_OP_TLS_D5_BUG
	Indicates an ephemeral RSA encoding error. More...
#define	SSL_OP_TLS_BLOCK_PADDING_BUG
	Indicates a Transport Layer Security (TLS) block encoding error. More...
#define	SSL_OP_TLS_ROLLBACK_BUG
	Indicates a Transport Layer Security (TLS) protocol rollback checking error. More...
#define	SSL_OP_MS_SGC
	Turns on compatibility with Microsoft Server Gated Cryptography (SGC). More...
#define	SSL_OP_DHANON_NULL_SIGNATURE_OK
	Indicates that the client should allow a `NULL` Diffie-Hellman anonymous signature rather than rejecting it.
#define	SSL_OP_ALL
	Enables the following bug compatibility options: SSL_OP_DHANON_NULL_SIGNATURE_OK. SSL_OP_MS_SGC. SSL_OP_TLS_ROLLBACK_BUG. SSL_OP_TLS_BLOCK_PADDING_BUG. SSL_OP_TLS_D5_BUG. SSL_OP_SSLEAY_080_CLIENT_DH_BUG. SSL_OP_MSIE_SSLV2_RSA_PADDING. SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER. SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG. SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG. SSL_OP_NETSCAPE_CHALLENGE_BUG. SSL_OP_MICROSOFT_SESS_ID_BUG. More...
#define	SSL_OP_MULTIPRIME_TMP_RSA_KEYS
	Turns on MultiPrime for temporary RSA key generation.
#define	SSL_OP_QUIET_SHUTDOWN
	Enables shutdown without sending a notification to the peer. More...
#define	SSL_OP_ANYTIME_SHUTDOWN
	Enables shutdown at any time including during the handshake. More...
#define	SSL_OP_SSLC2_DH_BUG
	Enables compatibility with SSL-C 2.0 and SSL-J 4.x when using Diffie-Hellman key exchange.
#define	SSL_OP_SINGLE_DH_USE
	Ensures `tmp_dh` parameters are used only once.
#define	SSL_OP_EPHEMERAL_RSA
	Uses the `tmp_rsa` key during RSA operations.
#define	SSL_OP_REUSE_DELAY_CLIENT_FINISHED
	Indicates that reuse delay client is finished. More...
#define	SSL_OP_DELAY_READ_SERVER_FINISHED
	Delays reading of the server finished message on the client until the after sending the first block of application data. More...
#define	SSL_OP_NO_SSLv2
	Prevents an SSLv2 connection. More...
#define	SSL_OP_NO_SSLv3
	Prevents an SSLv3 connection. More...
#define	SSL_OP_NO_TLSv1
	Prevents a Transport Layer Security (TLS) v1 connection. More...
#define	SSL_OP_PKCS1_CHECK_1
	Deliberately changes the ciphertext and is a check for the PKCS #1 attack (that is, diagnostic code).
#define	SSL_OP_PKCS1_CHECK_2
	Deliberately changes the ciphertext and is a check for the PKCS #1 attack (that is, diagnostic code).
#define	SSL_OP_NETSCAPE_CA_DN_BUG
	Indicates a Netscape SSLv3 Certification Authority (CA) Distinguished Name (DN) encoding error. More...
#define	SSL_OP_NON_EXPORT_FIRST
	Prevents the server from automatically upgrading an SSLv23 handshake to SSLv3 where no strong (that is, non export) SSLv3 cipher suites are supported by the client (but strong SSLv2 cipher suites are available).
#define	SSL_OP_NETSCAPE_DEMO_CIPHER_CHANGE_BUG
	A bug compatibility flag.

Define Documentation

#define SSL_OP_ALL

Enables the following bug compatibility options:
SSL_OP_DHANON_NULL_SIGNATURE_OK.
SSL_OP_MS_SGC.
SSL_OP_TLS_ROLLBACK_BUG.
SSL_OP_TLS_BLOCK_PADDING_BUG.
SSL_OP_TLS_D5_BUG.
SSL_OP_SSLEAY_080_CLIENT_DH_BUG.
SSL_OP_MSIE_SSLV2_RSA_PADDING.
SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER.
SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG.
SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG.
SSL_OP_NETSCAPE_CHALLENGE_BUG.
SSL_OP_MICROSOFT_SESS_ID_BUG.

Further options can be combined using the bit wise operation.

#define SSL_OP_ANYTIME_SHUTDOWN

Enables shutdown at any time including during the handshake.
See also:
SSL_CTX_set_anytime_shutdown() and SSL_set_anytime_shutdown().

#define SSL_OP_DELAY_READ_SERVER_FINISHED

Delays reading of the server finished message on the client until the after sending the first block of application data. This option change deliberately deviates from the SSL protocol to increase the speed of the handshake.

#define SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER

Indicates a large SSLv3 packet error. Some versions of Microsoft IE send SSLv3 packets greater than 18k+5 Bytes which is prohibited by the SSLv3 specification. Navigator rejects the large packets. Enabling this option allows SSL connections to read the large packets.

#define SSL_OP_MICROSOFT_SESS_ID_BUG

Indicates a Microsoft SSLv2 session identifier reuse error. This error occurs with SSLv2 when using session identifier reuse - the session identifier returned in the ServerFinished message is different from the one the client originally passed in. Old versions of Microsoft servers may still contain this bug in their SSLv2 implementation.

#define SSL_OP_MS_SGC

Turns on compatibility with Microsoft Server Gated Cryptography (SGC). SGC allows the use of strong cryptography under export conditions in approved circumstances.

#define SSL_OP_MSIE_SSLV2_RSA_PADDING

Indicates Microsoft SSLv2 rollback attacks on SSLv3 clients. When doing SSLv2 (SSLv3 turned off), MSIE 3.02 always uses the SSLv23 special PKCS #1 padding (8 Bytes of value 3). This should not occur for connections that only request SSLv2.

#define SSL_OP_NETSCAPE_CA_DN_BUG

Indicates a Netscape SSLv3 Certification Authority (CA) Distinguished Name (DN) encoding error. Some Netscape web servers do not encode CAs' DNs correctly when prompting for a client certificate. The outer sequence on each DN is missing. This bug option provides an alternative encoding system.

#define SSL_OP_NETSCAPE_CHALLENGE_BUG

Indicates a Netscape SSLv2 challenge length error. Netscape-Commerce v1.12 using SSLv2 accepts a 32-Byte challenge. However, only 16 Bytes are used for generating the encryption keys. According to the SSLv3 specification the challenge should be 32 Bytes when operating in SSLv23 compatibility mode. However, since this breaks the server, developers must use only 16 Bytes. This error is serious because it means all SSLv23 client applications must use 16-Byte challenge keys, instead of 32 as recommended by the specification. Enabling this operation works around this issue.

#define SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG

Indicates a Netscape SSLv3 changing reused cipher error. The first available cipher is used when establishing an SSLv3 connection. If a session is resumed, a different cipher may be chosen if it precedes the previously chosen cipher in the list. Enabling this option permits cipher changes.

#define SSL_OP_NO_SSLv2

Prevents an SSLv2 connection. This option is only applicable when connecting with SSLv23. It prevents the peers choosing SSLv2 as the protocol version.

#define SSL_OP_NO_SSLv3

Prevents an SSLv3 connection. This option is only applicable when connecting with SSLv23. It prevents the peers choosing SSLv3 as the protocol version.

#define SSL_OP_NO_TLSv1

Prevents a Transport Layer Security (TLS) v1 connection. This option is only applicable when connecting with SSLv23. It prevents the peers choosing TLSv1 as the protocol version.

#define SSL_OP_QUIET_SHUTDOWN

Enables shutdown without sending a notification to the peer.
See also:
SSL_CTX_set_quiet_shutdown() and SSL_set_quiet_shutdown().

#define SSL_OP_REUSE_DELAY_CLIENT_FINISHED

Indicates that reuse delay client is finished. Enables a mode whereby if session identifier reuse occurs, the protocol's final Finish message is not sent until the first SSL_write() after the handshake. This flag removes a timeout at connection startup. If set, the client must write (rather than read) data as the first operation. If the first operation is a read, an application deadlock occurs because the ClientFinished message has not been sent to the server. Consequently the server has not sent data for the client to read.

#define SSL_OP_SSLEAY_080_CLIENT_DH_BUG

Indicates an SSLeay version 0.8.0 Diffie-Hellman encoding error. SSLeay version 0.8.0 incorrectly encoded Diffie-Hellman parameters. This bug enables handling of the incorrect format.

#define SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG

Indicates an SSLv2 session identifier reuse certificate type error. If SSL_reuse() is true then the CERTIFICATE-TYPE, CERTIFICATE-LENGTH and CIPHER-SPECS-LENGTH fields should be 0. Some Netscape web servers do not implement this correctly.

#define SSL_OP_TLS_BLOCK_PADDING_BUG

Indicates a Transport Layer Security (TLS) block encoding error. Some TLS implementations incorrectly implement the encoding of the padding length when using block ciphers.

#define SSL_OP_TLS_D5_BUG

Indicates an ephemeral RSA encoding error. Some TLS implementations incorrectly encode the length of ephemeral RSA parameters.

D5 refers to the fifth draft of the TLS protocol where this issue was first noted.

#define SSL_OP_TLS_ROLLBACK_BUG

Indicates a Transport Layer Security (TLS) protocol rollback checking error. Some TLS implementations did not check the protocol version encoded in the random data exchanged between the client and server. This option enables protocol version checking to provide compatibility with implementations that do not set this field correctly.

Option Codes

Defines

Define Documentation