diff --git a/crypto/openssl/doc/man3/SSL_CONF_cmd.pod b/crypto/openssl/doc/man3/SSL_CONF_cmd.pod index 900c4f3a5648..a3f447a986e3 100644 --- a/crypto/openssl/doc/man3/SSL_CONF_cmd.pod +++ b/crypto/openssl/doc/man3/SSL_CONF_cmd.pod @@ -1,704 +1,708 @@ =pod =head1 NAME SSL_CONF_cmd_value_type, SSL_CONF_cmd - send configuration command =head1 SYNOPSIS #include int SSL_CONF_cmd(SSL_CONF_CTX *cctx, const char *cmd, const char *value); int SSL_CONF_cmd_value_type(SSL_CONF_CTX *cctx, const char *cmd); =head1 DESCRIPTION The function SSL_CONF_cmd() performs configuration operation B with optional parameter B on B. Its purpose is to simplify application configuration of B or B structures by providing a common framework for command line options or configuration files. SSL_CONF_cmd_value_type() returns the type of value that B refers to. =head1 SUPPORTED COMMAND LINE COMMANDS Currently supported B names for command lines (i.e. when the flag B is set) are listed below. Note: all B names are case sensitive. Unless otherwise stated commands can be used by both clients and servers and the B parameter is not used. The default prefix for command line commands is B<-> and that is reflected below. =over 4 =item B<-sigalgs> This sets the supported signature algorithms for TLSv1.2 and TLSv1.3. For clients this value is used directly for the supported signature algorithms extension. For servers it is used to determine which signature algorithms to support. The B argument should be a colon separated list of signature algorithms in order of decreasing preference of the form B or B. B is one of B, B or B and B is a supported algorithm OID short name such as B, B, B, B of B. Note: algorithm and hash names are case sensitive. B is one of the signature schemes defined in TLSv1.3, specified using the IETF name, e.g., B, B, or B. If this option is not set then all signature algorithms supported by the OpenSSL library are permissible. Note: algorithms which specify a PKCS#1 v1.5 signature scheme (either by using B as the B or by using one of the B identifiers) are ignored in TLSv1.3 and will not be negotiated. =item B<-client_sigalgs> This sets the supported signature algorithms associated with client authentication for TLSv1.2 and TLSv1.3. For servers the value is used in the B field of a B message. For clients it is used to determine which signature algorithm to use with the client certificate. If a server does not request a certificate this option has no effect. The syntax of B is identical to B<-sigalgs>. If not set then the value set for B<-sigalgs> will be used instead. =item B<-groups> This sets the supported groups. For clients, the groups are sent using the supported groups extension. For servers, it is used to determine which group to use. This setting affects groups used for signatures (in TLSv1.2 and earlier) and key exchange. The first group listed will also be used for the B sent by a client in a TLSv1.3 B. The B argument is a colon separated list of groups. The group can be either the B name (e.g. B), some other commonly used name where applicable (e.g. B) or an OpenSSL OID name (e.g. B). Group names are case sensitive. The list should be in order of preference with the most preferred group first. =item B<-curves> This is a synonym for the "-groups" command. =item B<-named_curve> This sets the temporary curve used for ephemeral ECDH modes. Only used by servers The B argument is a curve name or the special value B which picks an appropriate curve based on client and server preferences. The curve can be either the B name (e.g. B) or an OpenSSL OID name (e.g. B). Curve names are case sensitive. =item B<-cipher> Sets the TLSv1.2 and below ciphersuite list to B. This list will be combined with any configured TLSv1.3 ciphersuites. Note: syntax checking of B is currently not performed unless a B or B structure is associated with B. =item B<-ciphersuites> Sets the available ciphersuites for TLSv1.3 to value. This is a simple colon (":") separated list of TLSv1.3 ciphersuite names in order of preference. This list will be combined any configured TLSv1.2 and below ciphersuites. See L for more information. =item B<-cert> Attempts to use the file B as the certificate for the appropriate context. It currently uses SSL_CTX_use_certificate_chain_file() if an B structure is set or SSL_use_certificate_file() with filetype PEM if an B structure is set. This option is only supported if certificate operations are permitted. =item B<-key> Attempts to use the file B as the private key for the appropriate context. This option is only supported if certificate operations are permitted. Note: if no B<-key> option is set then a private key is not loaded unless the flag B is set. =item B<-dhparam> Attempts to use the file B as the set of temporary DH parameters for the appropriate context. This option is only supported if certificate operations are permitted. =item B<-record_padding> Attempts to pad TLSv1.3 records so that they are a multiple of B in length on send. A B of 0 or 1 turns off padding. Otherwise, the B must be >1 or <=16384. =item B<-no_renegotiation> Disables all attempts at renegotiation in TLSv1.2 and earlier, same as setting B. =item B<-min_protocol>, B<-max_protocol> Sets the minimum and maximum supported protocol. Currently supported protocol values are B, B, B, B, B for TLS; B, B for DTLS, and B for no limit. If either the lower or upper bound is not specified then only the other bound applies, if specified. If your application supports both TLS and DTLS you can specify any of these options twice, once with a bound for TLS and again with an appropriate bound for DTLS. To restrict the supported protocol versions use these commands rather than the deprecated alternative commands below. =item B<-no_ssl3>, B<-no_tls1>, B<-no_tls1_1>, B<-no_tls1_2>, B<-no_tls1_3> Disables protocol support for SSLv3, TLSv1.0, TLSv1.1, TLSv1.2 or TLSv1.3 by setting the corresponding options B, B, B, B and B respectively. These options are deprecated, instead use B<-min_protocol> and B<-max_protocol>. =item B<-bugs> Various bug workarounds are set, same as setting B. =item B<-comp> Enables support for SSL/TLS compression, same as clearing B. This command was introduced in OpenSSL 1.1.0. As of OpenSSL 1.1.0, compression is off by default. =item B<-no_comp> Disables support for SSL/TLS compression, same as setting B. As of OpenSSL 1.1.0, compression is off by default. =item B<-no_ticket> Disables support for session tickets, same as setting B. =item B<-serverpref> Use server and not client preference order when determining which cipher suite, signature algorithm or elliptic curve to use for an incoming connection. Equivalent to B. Only used by servers. =item B<-prioritize_chacha> Prioritize ChaCha ciphers when the client has a ChaCha20 cipher at the top of its preference list. This usually indicates a client without AES hardware acceleration (e.g. mobile) is in use. Equivalent to B. Only used by servers. Requires B<-serverpref>. =item B<-no_resumption_on_reneg> set SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION flag. Only used by servers. =item B<-legacyrenegotiation> permits the use of unsafe legacy renegotiation. Equivalent to setting B. =item B<-legacy_server_connect>, B<-no_legacy_server_connect> permits or prohibits the use of unsafe legacy renegotiation for OpenSSL clients only. Equivalent to setting or clearing B. Set by default. =item B<-allow_no_dhe_kex> In TLSv1.3 allow a non-(ec)dhe based key exchange mode on resumption. This means that there will be no forward secrecy for the resumed session. =item B<-strict> enables strict mode protocol handling. Equivalent to setting B. =item B<-anti_replay>, B<-no_anti_replay> Switches replay protection, on or off respectively. With replay protection on, OpenSSL will automatically detect if a session ticket has been used more than once, TLSv1.3 has been negotiated, and early data is enabled on the server. A full handshake is forced if a session ticket is used a second or subsequent time. Anti-Replay is on by default unless overridden by a configuration file and is only used by servers. Anti-replay measures are required for compliance with the TLSv1.3 specification. Some applications may be able to mitigate the replay risks in other ways and in such cases the built-in OpenSSL functionality is not required. Switching off anti-replay is equivalent to B. =back =head1 SUPPORTED CONFIGURATION FILE COMMANDS Currently supported B names for configuration files (i.e. when the flag B is set) are listed below. All configuration file B names are case insensitive so B is recognised as well as B. Unless otherwise stated the B names are also case insensitive. Note: the command prefix (if set) alters the recognised B values. =over 4 =item B Sets the ciphersuite list for TLSv1.2 and below to B. This list will be combined with any configured TLSv1.3 ciphersuites. Note: syntax checking of B is currently not performed unless an B or B structure is associated with B. =item B Sets the available ciphersuites for TLSv1.3 to B. This is a simple colon (":") separated list of TLSv1.3 ciphersuite names in order of preference. This list will be combined any configured TLSv1.2 and below ciphersuites. See L for more information. =item B Attempts to use the file B as the certificate for the appropriate context. It currently uses SSL_CTX_use_certificate_chain_file() if an B structure is set or SSL_use_certificate_file() with filetype PEM if an B structure is set. This option is only supported if certificate operations are permitted. =item B Attempts to use the file B as the private key for the appropriate context. This option is only supported if certificate operations are permitted. Note: if no B option is set then a private key is not loaded unless the B is set. =item B, B, B, B These options indicate a file or directory used for building certificate chains or verifying certificate chains. These options are only supported if certificate operations are permitted. =item B This option indicates a file containing a set of certificates in PEM form. The subject names of the certificates are sent to the peer in the B extension for TLS 1.3 (in ClientHello or CertificateRequest) or in a certificate request for previous versions or TLS. =item B Attempts to use the file B in the "serverinfo" extension using the function SSL_CTX_use_serverinfo_file. =item B Attempts to use the file B as the set of temporary DH parameters for the appropriate context. This option is only supported if certificate operations are permitted. =item B Attempts to pad TLSv1.3 records so that they are a multiple of B in length on send. A B of 0 or 1 turns off padding. Otherwise, the B must be >1 or <=16384. =item B This sets the supported signature algorithms for TLSv1.2 and TLSv1.3. For clients this value is used directly for the supported signature algorithms extension. For servers it is used to determine which signature algorithms to support. The B argument should be a colon separated list of signature algorithms in order of decreasing preference of the form B or B. B is one of B, B or B and B is a supported algorithm OID short name such as B, B, B, B of B. Note: algorithm and hash names are case sensitive. B is one of the signature schemes defined in TLSv1.3, specified using the IETF name, e.g., B, B, or B. If this option is not set then all signature algorithms supported by the OpenSSL library are permissible. Note: algorithms which specify a PKCS#1 v1.5 signature scheme (either by using B as the B or by using one of the B identifiers) are ignored in TLSv1.3 and will not be negotiated. =item B This sets the supported signature algorithms associated with client authentication for TLSv1.2 and TLSv1.3. For servers the value is used in the B field of a B message. For clients it is used to determine which signature algorithm to use with the client certificate. If a server does not request a certificate this option has no effect. The syntax of B is identical to B. If not set then the value set for B will be used instead. =item B This sets the supported groups. For clients, the groups are sent using the supported groups extension. For servers, it is used to determine which group to use. This setting affects groups used for signatures (in TLSv1.2 and earlier) and key exchange. The first group listed will also be used for the B sent by a client in a TLSv1.3 B. The B argument is a colon separated list of groups. The group can be either the B name (e.g. B), some other commonly used name where applicable (e.g. B) or an OpenSSL OID name (e.g. B). Group names are case sensitive. The list should be in order of preference with the most preferred group first. =item B This is a synonym for the "Groups" command. =item B This sets the minimum supported SSL, TLS or DTLS version. Currently supported protocol values are B, B, B, B, B, B and B. The SSL and TLS bounds apply only to TLS-based contexts, while the DTLS bounds apply only to DTLS-based contexts. The command can be repeated with one instance setting a TLS bound, and the other setting a DTLS bound. The value B applies to both types of contexts and disables the limits. =item B This sets the maximum supported SSL, TLS or DTLS version. Currently supported protocol values are B, B, B, B, B, B and B. The SSL and TLS bounds apply only to TLS-based contexts, while the DTLS bounds apply only to DTLS-based contexts. The command can be repeated with one instance setting a TLS bound, and the other setting a DTLS bound. The value B applies to both types of contexts and disables the limits. =item B This can be used to enable or disable certain versions of the SSL, TLS or DTLS protocol. The B argument is a comma separated list of supported protocols to enable or disable. If a protocol is preceded by B<-> that version is disabled. All protocol versions are enabled by default. You need to disable at least one protocol version for this setting have any effect. Only enabling some protocol versions does not disable the other protocol versions. Currently supported protocol values are B, B, B, B, B, B and B. The special value B refers to all supported versions. This can't enable protocols that are disabled using B or B, but can disable protocols that are still allowed by them. The B command is fragile and deprecated; do not use it. Use B and B instead. If you do use B, make sure that the resulting range of enabled protocols has no "holes", e.g. if TLS 1.0 and TLS 1.2 are both enabled, make sure to also leave TLS 1.1 enabled. =item B The B argument is a comma separated list of various flags to set. If a flag string is preceded B<-> it is disabled. See the L function for more details of individual options. Each option is listed below. Where an operation is enabled by default the B<-flag> syntax is needed to disable it. B: session ticket support, enabled by default. Inverse of B: that is B<-SessionTicket> is the same as setting B. B: SSL/TLS compression support, enabled by default. Inverse of B. B: use empty fragments as a countermeasure against a SSL 3.0/TLS 1.0 protocol vulnerability affecting CBC ciphers. It is set by default. Inverse of B. B: enable various bug workarounds. Same as B. B: enable single use DH keys, set by default. Inverse of B. Only used by servers. B: enable single use ECDH keys, set by default. Inverse of B. Only used by servers. B: use server and not client preference order when determining which cipher suite, signature algorithm or elliptic curve to use for an incoming connection. Equivalent to B. Only used by servers. B: prioritizes ChaCha ciphers when the client has a ChaCha20 cipher at the top of its preference list. This usually indicates a mobile client is in use. Equivalent to B. Only used by servers. B: set B flag. Only used by servers. B: disables all attempts at renegotiation in TLSv1.2 and earlier, same as setting B. B: permits the use of unsafe legacy renegotiation. Equivalent to B. B: permits the use of unsafe legacy renegotiation for OpenSSL clients only. Equivalent to B. Set by default. B: use encrypt-then-mac extension, enabled by default. Inverse of B: that is, B<-EncryptThenMac> is the same as setting B. B: In TLSv1.3 allow a non-(ec)dhe based key exchange mode on resumption. This means that there will be no forward secrecy for the resumed session. Equivalent to B. B: If set then dummy Change Cipher Spec (CCS) messages are sent in TLSv1.3. This has the effect of making TLSv1.3 look more like TLSv1.2 so that middleboxes that do not understand TLSv1.3 will not drop the connection. This option is set by default. A future version of OpenSSL may not set this by default. Equivalent to B. B: If set then OpenSSL will automatically detect if a session ticket has been used more than once, TLSv1.3 has been negotiated, and early data is enabled on the server. A full handshake is forced if a session ticket is used a second or subsequent time. This option is set by default and is only used by servers. Anti-replay measures are required to comply with the TLSv1.3 specification. Some applications may be able to mitigate the replay risks in other ways and in such cases the built-in OpenSSL functionality is not required. Disabling anti-replay is equivalent to setting B. +B: Enables kernel TLS if support has been compiled in, and it is supported +by the negotiated ciphersuites and extensions. Equivalent to +B. + =item B The B argument is a comma separated list of flags to set. B enables peer verification: for clients only. B requests but does not require a certificate from the client. Servers only. B requests and requires a certificate from the client: an error occurs if the client does not present a certificate. Servers only. B requests a certificate from a client only on the initial connection: not when renegotiating. Servers only. B configures the connection to support requests but does not require a certificate from the client post-handshake. A certificate will not be requested during the initial handshake. The server application must provide a mechanism to request a certificate post-handshake. Servers only. TLSv1.3 only. B configures the connection to support requests and requires a certificate from the client post-handshake: an error occurs if the client does not present a certificate. A certificate will not be requested during the initial handshake. The server application must provide a mechanism to request a certificate post-handshake. Servers only. TLSv1.3 only. =item B, B A file or directory of certificates in PEM format whose names are used as the set of acceptable names for client CAs. Servers only. This option is only supported if certificate operations are permitted. =back =head1 SUPPORTED COMMAND TYPES The function SSL_CONF_cmd_value_type() currently returns one of the following types: =over 4 =item B The B string is unrecognised, this return value can be use to flag syntax errors. =item B The value is a string without any specific structure. =item B The value is a filename. =item B The value is a directory name. =item B The value string is not used e.g. a command line option which doesn't take an argument. =back =head1 NOTES The order of operations is significant. This can be used to set either defaults or values which cannot be overridden. For example if an application calls: SSL_CONF_cmd(ctx, "Protocol", "-SSLv3"); SSL_CONF_cmd(ctx, userparam, uservalue); it will disable SSLv3 support by default but the user can override it. If however the call sequence is: SSL_CONF_cmd(ctx, userparam, uservalue); SSL_CONF_cmd(ctx, "Protocol", "-SSLv3"); SSLv3 is B disabled and attempt to override this by the user are ignored. By checking the return code of SSL_CONF_cmd() it is possible to query if a given B is recognised, this is useful if SSL_CONF_cmd() values are mixed with additional application specific operations. For example an application might call SSL_CONF_cmd() and if it returns -2 (unrecognised command) continue with processing of application specific commands. Applications can also use SSL_CONF_cmd() to process command lines though the utility function SSL_CONF_cmd_argv() is normally used instead. One way to do this is to set the prefix to an appropriate value using SSL_CONF_CTX_set1_prefix(), pass the current argument to B and the following argument to B (which may be NULL). In this case if the return value is positive then it is used to skip that number of arguments as they have been processed by SSL_CONF_cmd(). If -2 is returned then B is not recognised and application specific arguments can be checked instead. If -3 is returned a required argument is missing and an error is indicated. If 0 is returned some other error occurred and this can be reported back to the user. The function SSL_CONF_cmd_value_type() can be used by applications to check for the existence of a command or to perform additional syntax checking or translation of the command value. For example if the return value is B an application could translate a relative pathname to an absolute pathname. =head1 RETURN VALUES SSL_CONF_cmd() returns 1 if the value of B is recognised and B is B used and 2 if both B and B are used. In other words it returns the number of arguments processed. This is useful when processing command lines. A return value of -2 means B is not recognised. A return value of -3 means B is recognised and the command requires a value but B is NULL. A return code of 0 indicates that both B and B are valid but an error occurred attempting to perform the operation: for example due to an error in the syntax of B in this case the error queue may provide additional information. =head1 EXAMPLES Set supported signature algorithms: SSL_CONF_cmd(ctx, "SignatureAlgorithms", "ECDSA+SHA256:RSA+SHA256:DSA+SHA256"); There are various ways to select the supported protocols. This set the minimum protocol version to TLSv1, and so disables SSLv3. This is the recommended way to disable protocols. SSL_CONF_cmd(ctx, "MinProtocol", "TLSv1"); The following also disables SSLv3: SSL_CONF_cmd(ctx, "Protocol", "-SSLv3"); The following will first enable all protocols, and then disable SSLv3. If no protocol versions were disabled before this has the same effect as "-SSLv3", but if some versions were disables this will re-enable them before disabling SSLv3. SSL_CONF_cmd(ctx, "Protocol", "ALL,-SSLv3"); Only enable TLSv1.2: SSL_CONF_cmd(ctx, "MinProtocol", "TLSv1.2"); SSL_CONF_cmd(ctx, "MaxProtocol", "TLSv1.2"); This also only enables TLSv1.2: SSL_CONF_cmd(ctx, "Protocol", "-ALL,TLSv1.2"); Disable TLS session tickets: SSL_CONF_cmd(ctx, "Options", "-SessionTicket"); Enable compression: SSL_CONF_cmd(ctx, "Options", "Compression"); Set supported curves to P-256, P-384: SSL_CONF_cmd(ctx, "Curves", "P-256:P-384"); =head1 SEE ALSO L, L, L, L, L, L =head1 HISTORY The SSL_CONF_cmd() function was added in OpenSSL 1.0.2. The B option doesn't have effect since 1.1.0, but the macro is retained for backwards compatibility. The B was added in OpenSSL 1.1.0. In earlier versions of OpenSSL passing a command which didn't take an argument would return B. B and B where added in OpenSSL 1.1.0. B and B were added in OpenSSL 1.1.1. =head1 COPYRIGHT Copyright 2012-2020 The OpenSSL Project Authors. All Rights Reserved. Licensed under the OpenSSL license (the "License"). You may not use this file except in compliance with the License. You can obtain a copy in the file LICENSE in the source distribution or at L. =cut diff --git a/crypto/openssl/doc/man3/SSL_CTX_set_mode.pod b/crypto/openssl/doc/man3/SSL_CTX_set_mode.pod index 27eaebad1ea0..85e3353e0e2c 100644 --- a/crypto/openssl/doc/man3/SSL_CTX_set_mode.pod +++ b/crypto/openssl/doc/man3/SSL_CTX_set_mode.pod @@ -1,164 +1,147 @@ =pod =head1 NAME SSL_CTX_set_mode, SSL_CTX_clear_mode, SSL_set_mode, SSL_clear_mode, SSL_CTX_get_mode, SSL_get_mode - manipulate SSL engine mode =head1 SYNOPSIS #include long SSL_CTX_set_mode(SSL_CTX *ctx, long mode); long SSL_CTX_clear_mode(SSL_CTX *ctx, long mode); long SSL_set_mode(SSL *ssl, long mode); long SSL_clear_mode(SSL *ssl, long mode); long SSL_CTX_get_mode(SSL_CTX *ctx); long SSL_get_mode(SSL *ssl); =head1 DESCRIPTION SSL_CTX_set_mode() adds the mode set via bit mask in B to B. Options already set before are not cleared. SSL_CTX_clear_mode() removes the mode set via bit mask in B from B. SSL_set_mode() adds the mode set via bit mask in B to B. Options already set before are not cleared. SSL_clear_mode() removes the mode set via bit mask in B from B. SSL_CTX_get_mode() returns the mode set for B. SSL_get_mode() returns the mode set for B. =head1 NOTES The following mode changes are available: =over 4 =item SSL_MODE_ENABLE_PARTIAL_WRITE Allow SSL_write_ex(..., n, &r) to return with 0 < r < n (i.e. report success when just a single record has been written). This works in a similar way for SSL_write(). When not set (the default), SSL_write_ex() or SSL_write() will only report success once the complete chunk was written. Once SSL_write_ex() or SSL_write() returns successful, B bytes have been written and the next call to SSL_write_ex() or SSL_write() must only send the n-r bytes left, imitating the behaviour of write(). =item SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER Make it possible to retry SSL_write_ex() or SSL_write() with changed buffer location (the buffer contents must stay the same). This is not the default to avoid the misconception that nonblocking SSL_write() behaves like nonblocking write(). =item SSL_MODE_AUTO_RETRY During normal operations, non-application data records might need to be sent or received that the application is not aware of. If a non-application data record was processed, L and L can return with a failure and indicate the need to retry with B. If such a non-application data record was processed, the flag B causes it to try to process the next record instead of returning. In a nonblocking environment applications must be prepared to handle incomplete read/write operations. Setting B for a nonblocking B will process non-application data records until either no more data is available or an application data record has been processed. In a blocking environment, applications are not always prepared to deal with the functions returning intermediate reports such as retry requests, and setting the B flag will cause the functions to only return after successfully processing an application data record or a failure. Turning off B can be useful with blocking Bs in case they are used in combination with something like select() or poll(). Otherwise the call to SSL_read() or SSL_read_ex() might hang when a non-application record was sent and no application data was sent. =item SSL_MODE_RELEASE_BUFFERS When we no longer need a read buffer or a write buffer for a given SSL, then release the memory we were using to hold it. Using this flag can save around 34k per idle SSL connection. This flag has no effect on SSL v2 connections, or on DTLS connections. =item SSL_MODE_SEND_FALLBACK_SCSV Send TLS_FALLBACK_SCSV in the ClientHello. To be set only by applications that reconnect with a downgraded protocol version; see draft-ietf-tls-downgrade-scsv-00 for details. DO NOT ENABLE THIS if your application attempts a normal handshake. Only use this in explicit fallback retries, following the guidance in draft-ietf-tls-downgrade-scsv-00. =item SSL_MODE_ASYNC Enable asynchronous processing. TLS I/O operations may indicate a retry with SSL_ERROR_WANT_ASYNC with this mode set if an asynchronous capable engine is used to perform cryptographic operations. See L. =item SSL_MODE_DTLS_SCTP_LABEL_LENGTH_BUG Older versions of OpenSSL had a bug in the computation of the label length used for computing the endpoint-pair shared secret. The bug was that the terminating zero was included in the length of the label. Setting this option enables this behaviour to allow interoperability with such broken implementations. Please note that setting this option breaks interoperability with correct implementations. This option only applies to DTLS over SCTP. -=item SSL_MODE_NO_KTLS_TX - -Disable the use of the kernel TLS egress data-path. -By default kernel TLS is enabled if it is supported by the negotiated ciphersuites -and extensions and OpenSSL has been compiled with support for it. -The kernel TLS data-path implements the record layer, -and the crypto algorithm. The kernel will utilize the best hardware -available for crypto. Using the kernel data-path should reduce the memory -footprint of OpenSSL because no buffering is required. Also, the throughput -should improve because data copy is avoided when user data is encrypted into -kernel memory instead of the usual encrypt than copy to kernel. - -Kernel TLS might not support all the features of OpenSSL. For instance, -renegotiation, and setting the maximum fragment size is not possible as of -Linux 4.20. - =back All modes are off by default except for SSL_MODE_AUTO_RETRY which is on by default since 1.1.1. =head1 RETURN VALUES SSL_CTX_set_mode() and SSL_set_mode() return the new mode bit mask after adding B. SSL_CTX_get_mode() and SSL_get_mode() return the current bit mask. =head1 SEE ALSO L, L, L, L or L, L =head1 HISTORY SSL_MODE_ASYNC was added in OpenSSL 1.1.0. -SSL_MODE_NO_KTLS_TX was first added to OpenSSL 3.0.0. =head1 COPYRIGHT Copyright 2001-2020 The OpenSSL Project Authors. All Rights Reserved. Licensed under the OpenSSL license (the "License"). You may not use this file except in compliance with the License. You can obtain a copy in the file LICENSE in the source distribution or at L. =cut diff --git a/crypto/openssl/doc/man3/SSL_CTX_set_options.pod b/crypto/openssl/doc/man3/SSL_CTX_set_options.pod index 969e0366c45a..231fe92d8e78 100644 --- a/crypto/openssl/doc/man3/SSL_CTX_set_options.pod +++ b/crypto/openssl/doc/man3/SSL_CTX_set_options.pod @@ -1,378 +1,401 @@ =pod =head1 NAME SSL_CTX_set_options, SSL_set_options, SSL_CTX_clear_options, SSL_clear_options, SSL_CTX_get_options, SSL_get_options, SSL_get_secure_renegotiation_support - manipulate SSL options =head1 SYNOPSIS #include long SSL_CTX_set_options(SSL_CTX *ctx, long options); long SSL_set_options(SSL *ssl, long options); long SSL_CTX_clear_options(SSL_CTX *ctx, long options); long SSL_clear_options(SSL *ssl, long options); long SSL_CTX_get_options(SSL_CTX *ctx); long SSL_get_options(SSL *ssl); long SSL_get_secure_renegotiation_support(SSL *ssl); =head1 DESCRIPTION SSL_CTX_set_options() adds the options set via bit mask in B to B. Options already set before are not cleared! SSL_set_options() adds the options set via bit mask in B to B. Options already set before are not cleared! SSL_CTX_clear_options() clears the options set via bit mask in B to B. SSL_clear_options() clears the options set via bit mask in B to B. SSL_CTX_get_options() returns the options set for B. SSL_get_options() returns the options set for B. SSL_get_secure_renegotiation_support() indicates whether the peer supports secure renegotiation. Note, this is implemented via a macro. =head1 NOTES The behaviour of the SSL library can be changed by setting several options. The options are coded as bit masks and can be combined by a bitwise B operation (|). 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 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 option setting is copied. Changes to B do not affect already created SSL objects. SSL_clear() does not affect the settings. The following B options are available: =over 4 =item SSL_OP_SAFARI_ECDHE_ECDSA_BUG Don't prefer ECDHE-ECDSA ciphers when the client appears to be Safari on OS X. OS X 10.8..10.8.3 has broken support for ECDHE-ECDSA ciphers. =item SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS Disables a countermeasure against a SSL 3.0/TLS 1.0 protocol vulnerability affecting CBC ciphers, which cannot be handled by some broken SSL implementations. This option has no effect for connections using other ciphers. =item SSL_OP_TLSEXT_PADDING Adds a padding extension to ensure the ClientHello size is never between 256 and 511 bytes in length. This is needed as a workaround for some implementations. =item SSL_OP_ALL All of the above bug workarounds plus B as mentioned below. =back It is usually safe to use B to enable the bug workaround options if compatibility with somewhat broken implementations is desired. The following B options are available: =over 4 =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_CIPHER_SERVER_PREFERENCE When choosing a cipher, use the server's preferences instead of the client preferences. When not set, the SSL server will always follow the clients preferences. When set, the SSL/TLS server will choose following its own preferences. =item SSL_OP_NO_SSLv3, SSL_OP_NO_TLSv1, SSL_OP_NO_TLSv1_1, SSL_OP_NO_TLSv1_2, SSL_OP_NO_TLSv1_3, SSL_OP_NO_DTLSv1, SSL_OP_NO_DTLSv1_2 These options turn off the SSLv3, TLSv1, TLSv1.1, TLSv1.2 or TLSv1.3 protocol versions with TLS or the DTLSv1, DTLSv1.2 versions with DTLS, respectively. As of OpenSSL 1.1.0, these options are deprecated, use L and L instead. =item SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION When performing renegotiation as a server, always start a new session (i.e., session resumption requests are only accepted in the initial handshake). This option is not needed for clients. =item SSL_OP_NO_COMPRESSION Do not use compression even if it is supported. =item SSL_OP_NO_QUERY_MTU Do not query the MTU. Only affects DTLS connections. =item SSL_OP_COOKIE_EXCHANGE Turn on Cookie Exchange as described in RFC4347 Section 4.2.1. Only affects DTLS connections. =item SSL_OP_NO_TICKET SSL/TLS supports two mechanisms for resuming sessions: session ids and stateless session tickets. When using session ids a copy of the session information is cached on the server and a unique id is sent to the client. When the client wishes to resume it provides the unique id so that the server can retrieve the session information from its cache. When using stateless session tickets the server uses a session ticket encryption key to encrypt the session information. This encrypted data is sent to the client as a "ticket". When the client wishes to resume it sends the encrypted data back to the server. The server uses its key to decrypt the data and resume the session. In this way the server can operate statelessly - no session information needs to be cached locally. The TLSv1.3 protocol only supports tickets and does not directly support session ids. However, OpenSSL allows two modes of ticket operation in TLSv1.3: stateful and stateless. Stateless tickets work the same way as in TLSv1.2 and below. Stateful tickets mimic the session id behaviour available in TLSv1.2 and below. The session information is cached on the server and the session id is wrapped up in a ticket and sent back to the client. When the client wishes to resume, it presents a ticket in the same way as for stateless tickets. The server can then extract the session id from the ticket and retrieve the session information from its cache. By default OpenSSL will use stateless tickets. The SSL_OP_NO_TICKET option will cause stateless tickets to not be issued. In TLSv1.2 and below this means no ticket gets sent to the client at all. In TLSv1.3 a stateful ticket will be sent. This is a server-side option only. In TLSv1.3 it is possible to suppress all tickets (stateful and stateless) from being sent by calling L or L. =item SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION Allow legacy insecure renegotiation between OpenSSL and unpatched clients or servers. See the B section for more details. =item SSL_OP_LEGACY_SERVER_CONNECT Allow legacy insecure renegotiation between OpenSSL and unpatched servers B: this option is currently set by default. See the B section for more details. =item SSL_OP_NO_ENCRYPT_THEN_MAC Normally clients and servers will transparently attempt to negotiate the RFC7366 Encrypt-then-MAC option on TLS and DTLS connection. If this option is set, Encrypt-then-MAC is disabled. Clients will not propose, and servers will not accept the extension. =item SSL_OP_NO_RENEGOTIATION Disable all renegotiation in TLSv1.2 and earlier. Do not send HelloRequest messages, and ignore renegotiation requests via ClientHello. =item SSL_OP_ALLOW_NO_DHE_KEX In TLSv1.3 allow a non-(ec)dhe based key exchange mode on resumption. This means that there will be no forward secrecy for the resumed session. =item SSL_OP_PRIORITIZE_CHACHA When SSL_OP_CIPHER_SERVER_PREFERENCE is set, temporarily reprioritize ChaCha20-Poly1305 ciphers to the top of the server cipher list if a ChaCha20-Poly1305 cipher is at the top of the client cipher list. This helps those clients (e.g. mobile) use ChaCha20-Poly1305 if that cipher is anywhere in the server cipher list; but still allows other clients to use AES and other ciphers. Requires B. =item SSL_OP_ENABLE_MIDDLEBOX_COMPAT If set then dummy Change Cipher Spec (CCS) messages are sent in TLSv1.3. This has the effect of making TLSv1.3 look more like TLSv1.2 so that middleboxes that do not understand TLSv1.3 will not drop the connection. Regardless of whether this option is set or not CCS messages received from the peer will always be ignored in TLSv1.3. This option is set by default. To switch it off use SSL_clear_options(). A future version of OpenSSL may not set this by default. =item SSL_OP_NO_ANTI_REPLAY By default, when a server is configured for early data (i.e., max_early_data > 0), OpenSSL will switch on replay protection. See L for a description of the replay protection feature. Anti-replay measures are required to comply with the TLSv1.3 specification. Some applications may be able to mitigate the replay risks in other ways and in such cases the built in OpenSSL functionality is not required. Those applications can turn this feature off by setting this option. This is a server-side opton only. It is ignored by clients. +=item SSL_OP_ENABLE_KTLS + +Enable the use of kernel TLS. In order to benefit from kernel TLS OpenSSL must +have been compiled with support for it, and it must be supported by the +negotiated ciphersuites and extensions. The specific ciphersuites and extensions +that are supported may vary by platform and kernel version. + +The kernel TLS data-path implements the record layer, and the encryption +algorithm. The kernel will utilize the best hardware +available for encryption. Using the kernel data-path should reduce the memory +footprint of OpenSSL because no buffering is required. Also, the throughput +should improve because data copy is avoided when user data is encrypted into +kernel memory instead of the usual encrypt then copy to kernel. + +Kernel TLS might not support all the features of OpenSSL. For instance, +renegotiation, and setting the maximum fragment size is not possible as of +Linux 4.20. + +Note that with kernel TLS enabled some cryptographic operations are performed +by the kernel directly and not via any available OpenSSL Providers. This might +be undesirable if, for example, the application requires all cryptographic +operations to be performed by the FIPS provider. + =back The following options no longer have any effect but their identifiers are retained for compatibility purposes: =over 4 =item SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG =item SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER =item SSL_OP_SSLEAY_080_CLIENT_DH_BUG =item SSL_OP_TLS_D5_BUG =item SSL_OP_TLS_BLOCK_PADDING_BUG =item SSL_OP_MSIE_SSLV2_RSA_PADDING =item SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG =item SSL_OP_MICROSOFT_SESS_ID_BUG =item SSL_OP_NETSCAPE_CHALLENGE_BUG =item SSL_OP_PKCS1_CHECK_1 =item SSL_OP_PKCS1_CHECK_2 =item SSL_OP_SINGLE_DH_USE =item SSL_OP_SINGLE_ECDH_USE =item SSL_OP_EPHEMERAL_RSA =back =head1 SECURE RENEGOTIATION OpenSSL always attempts to use secure renegotiation as described in RFC5746. This counters the prefix attack described in CVE-2009-3555 and elsewhere. This attack has far reaching consequences which application writers should be aware of. In the description below an implementation supporting secure renegotiation is referred to as I. A server not supporting secure renegotiation is referred to as I. The following sections describe the operations permitted by OpenSSL's secure renegotiation implementation. =head2 Patched client and server Connections and renegotiation are always permitted by OpenSSL implementations. =head2 Unpatched client and patched OpenSSL server The initial connection succeeds but client renegotiation is denied by the server with a B warning alert if TLS v1.0 is used or a fatal B alert in SSL v3.0. If the patched OpenSSL server attempts to renegotiate a fatal B alert is sent. This is because the server code may be unaware of the unpatched nature of the client. If the option B is set then renegotiation B succeeds. =head2 Patched OpenSSL client and unpatched server. If the option B or B is set then initial connections and renegotiation between patched OpenSSL clients and unpatched servers succeeds. If neither option is set then initial connections to unpatched servers will fail. The option B is currently set by default even though it has security implications: otherwise it would be impossible to connect to unpatched servers (i.e. all of them initially) and this is clearly not acceptable. Renegotiation is permitted because this does not add any additional security issues: during an attack clients do not see any renegotiations anyway. As more servers become patched the option B will B be set by default in a future version of OpenSSL. OpenSSL client applications wishing to ensure they can connect to unpatched servers should always B B OpenSSL client applications that want to ensure they can B connect to unpatched servers (and thus avoid any security issues) should always B B using SSL_CTX_clear_options() or SSL_clear_options(). The difference between the B and B options is that B enables initial connections and secure renegotiation between OpenSSL clients and unpatched servers B, while B allows initial connections and renegotiation between OpenSSL and unpatched clients or servers. =head1 RETURN VALUES SSL_CTX_set_options() and SSL_set_options() return the new options bit mask after adding B. SSL_CTX_clear_options() and SSL_clear_options() return the new options bit mask after clearing B. SSL_CTX_get_options() and SSL_get_options() return the current bit mask. SSL_get_secure_renegotiation_support() returns 1 is the peer supports secure renegotiation and 0 if it does not. =head1 SEE ALSO L, L, L, L, L, L =head1 HISTORY The attempt to always try to use secure renegotiation was added in OpenSSL 0.9.8m. The B and B options were added in OpenSSL 1.1.1. =head1 COPYRIGHT Copyright 2001-2020 The OpenSSL Project Authors. All Rights Reserved. Licensed under the OpenSSL license (the "License"). You may not use this file except in compliance with the License. You can obtain a copy in the file LICENSE in the source distribution or at L. =cut