8b84495380
Add support for ServerInfo SSL_CONF option and update documentation. This was wrongly omitted from the 1.0.2 release. Reviewed-by: Richard Levitte <levitte@openssl.org>
438 lines
16 KiB
Text
438 lines
16 KiB
Text
=pod
|
|
|
|
=head1 NAME
|
|
|
|
SSL_CONF_cmd - send configuration command
|
|
|
|
=head1 SYNOPSIS
|
|
|
|
#include <openssl/ssl.h>
|
|
|
|
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);
|
|
int SSL_CONF_finish(SSL_CONF_CTX *cctx);
|
|
|
|
=head1 DESCRIPTION
|
|
|
|
The function SSL_CONF_cmd() performs configuration operation B<cmd> with
|
|
optional parameter B<value> on B<ctx>. Its purpose is to simplify application
|
|
configuration of B<SSL_CTX> or B<SSL> 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<cmd> refers to.
|
|
|
|
The function SSL_CONF_finish() must be called after all configuration
|
|
operations have been completed. It is used to finalise any operations
|
|
or to process defaults.
|
|
|
|
=head1 SUPPORTED COMMAND LINE COMMANDS
|
|
|
|
Currently supported B<cmd> names for command lines (i.e. when the
|
|
flag B<SSL_CONF_CMDLINE> is set) are listed below. Note: all B<cmd> names
|
|
are case sensitive. Unless otherwise stated commands can be used by
|
|
both clients and servers and the B<value> 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 TLS v1.2. 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<value> argument should be a colon separated list of signature algorithms
|
|
in order of decreasing preference of the form B<algorithm+hash>. B<algorithm>
|
|
is one of B<RSA>, B<DSA> or B<ECDSA> and B<hash> is a supported algorithm
|
|
OID short name such as B<SHA1>, B<SHA224>, B<SHA256>, B<SHA384> of B<SHA512>.
|
|
Note: algorithm and hash names are case sensitive.
|
|
|
|
If this option is not set then all signature algorithms supported by the
|
|
OpenSSL library are permissible.
|
|
|
|
=item B<-client_sigalgs>
|
|
|
|
This sets the supported signature algorithms associated with client
|
|
authentication for TLS v1.2. For servers the value is used in the supported
|
|
signature algorithms field of a certificate request. For clients it is
|
|
used to determine which signature algorithm to with the client certificate.
|
|
If a server does not request a certificate this option has no effect.
|
|
|
|
The syntax of B<value> is identical to B<-sigalgs>. If not set then
|
|
the value set for B<-sigalgs> will be used instead.
|
|
|
|
=item B<-curves>
|
|
|
|
This sets the supported elliptic curves. For clients the curves are
|
|
sent using the supported curves extension. For servers it is used
|
|
to determine which curve to use. This setting affects curves used for both
|
|
signatures and key exchange, if applicable.
|
|
|
|
The B<value> argument is a colon separated list of curves. The curve can be
|
|
either the B<NIST> name (e.g. B<P-256>) or an OpenSSL OID name (e.g
|
|
B<prime256v1>). Curve names are case sensitive.
|
|
|
|
=item B<-named_curve>
|
|
|
|
This sets the temporary curve used for ephemeral ECDH modes. Only used by
|
|
servers
|
|
|
|
The B<value> argument is a curve name or the special value B<auto> which
|
|
picks an appropriate curve based on client and server preferences. The curve
|
|
can be either the B<NIST> name (e.g. B<P-256>) or an OpenSSL OID name
|
|
(e.g B<prime256v1>). Curve names are case sensitive.
|
|
|
|
=item B<-cipher>
|
|
|
|
Sets the cipher suite list to B<value>. Note: syntax checking of B<value> is
|
|
currently not performed unless a B<SSL> or B<SSL_CTX> structure is
|
|
associated with B<cctx>.
|
|
|
|
=item B<-cert>
|
|
|
|
Attempts to use the file B<value> as the certificate for the appropriate
|
|
context. It currently uses SSL_CTX_use_certificate_chain_file() if an B<SSL_CTX>
|
|
structure is set or SSL_use_certificate_file() with filetype PEM if an B<SSL>
|
|
structure is set. This option is only supported if certificate operations
|
|
are permitted.
|
|
|
|
=item B<-key>
|
|
|
|
Attempts to use the file B<value> 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: it does not currently use the B<-cert> file.
|
|
|
|
=item B<-dhparam>
|
|
|
|
Attempts to use the file B<value> as the set of temporary DH parameters for
|
|
the appropriate context. This option is only supported if certificate
|
|
operations are permitted.
|
|
|
|
=item B<-no_ssl2>, B<-no_ssl3>, B<-no_tls1>, B<-no_tls1_1>, B<-no_tls1_2>
|
|
|
|
Disables protocol support for SSLv2, SSLv3, TLS 1.0, TLS 1.1 or TLS 1.2
|
|
by setting the corresponding options B<SSL_OP_NO_SSL2>, B<SSL_OP_NO_SSL3>,
|
|
B<SSL_OP_NO_TLS1>, B<SSL_OP_NO_TLS1_1> and B<SSL_OP_NO_TLS1_2> respectively.
|
|
|
|
=item B<-bugs>
|
|
|
|
Various bug workarounds are set, same as setting B<SSL_OP_ALL>.
|
|
|
|
=item B<-no_comp>
|
|
|
|
Disables support for SSL/TLS compression, same as setting B<SSL_OP_NO_COMPRESS>.
|
|
|
|
=item B<-no_ticket>
|
|
|
|
Disables support for session tickets, same as setting B<SSL_OP_NO_TICKET>.
|
|
|
|
=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<SSL_OP_CIPHER_SERVER_PREFERENCE>. Only used by servers.
|
|
|
|
=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<SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION>.
|
|
|
|
=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<SSL_OP_LEGACY_SERVER_CONNECT>.
|
|
Set by default.
|
|
|
|
=item B<-strict>
|
|
|
|
enables strict mode protocol handling. Equivalent to setting
|
|
B<SSL_CERT_FLAG_TLS_STRICT>.
|
|
|
|
=item B<-debug_broken_protocol>
|
|
|
|
disables various checks and permits several kinds of broken protocol behaviour
|
|
for testing purposes: it should B<NEVER> be used in anything other than a test
|
|
environment. Only supported if OpenSSL is configured with
|
|
B<-DOPENSSL_SSL_DEBUG_BROKEN_PROTOCOL>.
|
|
|
|
=back
|
|
|
|
=head1 SUPPORTED CONFIGURATION FILE COMMANDS
|
|
|
|
Currently supported B<cmd> names for configuration files (i.e. when the
|
|
flag B<SSL_CONF_FLAG_FILE> is set) are listed below. All configuration file
|
|
B<cmd> names and are case insensitive so B<signaturealgorithms> is recognised
|
|
as well as B<SignatureAlgorithms>. Unless otherwise stated the B<value> names
|
|
are also case insensitive.
|
|
|
|
Note: the command prefix (if set) alters the recognised B<cmd> values.
|
|
|
|
=over 4
|
|
|
|
=item B<CipherString>
|
|
|
|
Sets the cipher suite list to B<value>. Note: syntax checking of B<value> is
|
|
currently not performed unless an B<SSL> or B<SSL_CTX> structure is
|
|
associated with B<cctx>.
|
|
|
|
=item B<Certificate>
|
|
|
|
Attempts to use the file B<value> as the certificate for the appropriate
|
|
context. It currently uses SSL_CTX_use_certificate_chain_file() if an B<SSL_CTX>
|
|
structure is set or SSL_use_certificate_file() with filetype PEM if an B<SSL>
|
|
structure is set. This option is only supported if certificate operations
|
|
are permitted.
|
|
|
|
=item B<PrivateKey>
|
|
|
|
Attempts to use the file B<value> 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: it does not currently use the B<Certificate> file.
|
|
|
|
=item B<ServerInfoFile>
|
|
|
|
Attempts to use the file B<value> in the "serverinfo" extension using the
|
|
function SSL_CTX_use_serverinfo_file.
|
|
|
|
=item B<DHParameters>
|
|
|
|
Attempts to use the file B<value> as the set of temporary DH parameters for
|
|
the appropriate context. This option is only supported if certificate
|
|
operations are permitted.
|
|
|
|
=item B<SignatureAlgorithms>
|
|
|
|
This sets the supported signature algorithms for TLS v1.2. 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<value> argument should be a colon separated list of signature algorithms
|
|
in order of decreasing preference of the form B<algorithm+hash>. B<algorithm>
|
|
is one of B<RSA>, B<DSA> or B<ECDSA> and B<hash> is a supported algorithm
|
|
OID short name such as B<SHA1>, B<SHA224>, B<SHA256>, B<SHA384> of B<SHA512>.
|
|
Note: algorithm and hash names are case sensitive.
|
|
|
|
If this option is not set then all signature algorithms supported by the
|
|
OpenSSL library are permissible.
|
|
|
|
=item B<ClientSignatureAlgorithms>
|
|
|
|
This sets the supported signature algorithms associated with client
|
|
authentication for TLS v1.2. For servers the value is used in the supported
|
|
signature algorithms field of a certificate request. For clients it is
|
|
used to determine which signature algorithm to with the client certificate.
|
|
|
|
The syntax of B<value> is identical to B<SignatureAlgorithms>. If not set then
|
|
the value set for B<SignatureAlgorithms> will be used instead.
|
|
|
|
=item B<Curves>
|
|
|
|
This sets the supported elliptic curves. For clients the curves are
|
|
sent using the supported curves extension. For servers it is used
|
|
to determine which curve to use. This setting affects curves used for both
|
|
signatures and key exchange, if applicable.
|
|
|
|
The B<value> argument is a colon separated list of curves. The curve can be
|
|
either the B<NIST> name (e.g. B<P-256>) or an OpenSSL OID name (e.g
|
|
B<prime256v1>). Curve names are case sensitive.
|
|
|
|
=item B<ECDHParameters>
|
|
|
|
This sets the temporary curve used for ephemeral ECDH modes. Only used by
|
|
servers
|
|
|
|
The B<value> argument is a curve name or the special value B<Automatic> which
|
|
picks an appropriate curve based on client and server preferences. The curve
|
|
can be either the B<NIST> name (e.g. B<P-256>) or an OpenSSL OID name
|
|
(e.g B<prime256v1>). Curve names are case sensitive.
|
|
|
|
=item B<Protocol>
|
|
|
|
The supported versions of the SSL or TLS protocol.
|
|
|
|
The B<value> argument is a comma separated list of supported protocols to
|
|
enable or disable. If an protocol is preceded by B<-> that version is disabled.
|
|
All versions are enabled by default, though applications may choose to
|
|
explicitly disable some. Currently supported protocol values are B<SSLv2>,
|
|
B<SSLv3>, B<TLSv1>, B<TLSv1.1> and B<TLSv1.2>. The special value B<ALL> refers
|
|
to all supported versions.
|
|
|
|
=item B<Options>
|
|
|
|
The B<value> argument is a comma separated list of various flags to set.
|
|
If a flag string is preceded B<-> it is disabled. See the
|
|
B<SSL_CTX_set_options> 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<SessionTicket>: session ticket support, enabled by default. Inverse of
|
|
B<SSL_OP_NO_TICKET>: that is B<-SessionTicket> is the same as setting
|
|
B<SSL_OP_NO_TICKET>.
|
|
|
|
B<Compression>: SSL/TLS compression support, enabled by default. Inverse
|
|
of B<SSL_OP_NO_COMPRESSION>.
|
|
|
|
B<EmptyFragments>: 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<SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS>.
|
|
|
|
B<Bugs>: enable various bug workarounds. Same as B<SSL_OP_ALL>.
|
|
|
|
B<DHSingle>: enable single use DH keys, set by default. Inverse of
|
|
B<SSL_OP_DH_SINGLE>. Only used by servers.
|
|
|
|
B<ECDHSingle> enable single use ECDH keys, set by default. Inverse of
|
|
B<SSL_OP_ECDH_SINGLE>. Only used by servers.
|
|
|
|
B<ServerPreference> 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<SSL_OP_CIPHER_SERVER_PREFERENCE>. Only used by servers.
|
|
|
|
B<NoResumptionOnRenegotiation> set
|
|
B<SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION> flag. Only used by servers.
|
|
|
|
B<UnsafeLegacyRenegotiation> permits the use of unsafe legacy renegotiation.
|
|
Equivalent to B<SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION>.
|
|
|
|
B<UnsafeLegacyServerConnect> permits the use of unsafe legacy renegotiation
|
|
for OpenSSL clients only. Equivalent to B<SSL_OP_LEGACY_SERVER_CONNECT>.
|
|
Set by default.
|
|
|
|
=back
|
|
|
|
=head1 SUPPORTED COMMAND TYPES
|
|
|
|
The function SSL_CONF_cmd_value_type() currently returns one of the following
|
|
types:
|
|
|
|
=over 4
|
|
|
|
=item B<SSL_CONF_TYPE_UNKNOWN>
|
|
|
|
The B<cmd> string is unrecognised, this return value can be use to flag
|
|
syntax errors.
|
|
|
|
=item B<SSL_CONF_TYPE_STRING>
|
|
|
|
The value is a string without any specific structure.
|
|
|
|
=item B<SSL_CONF_TYPE_FILE>
|
|
|
|
The value is a file name.
|
|
|
|
=item B<SSL_CONF_TYPE_DIR>
|
|
|
|
The value is a directory name.
|
|
|
|
=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", "-SSLv2");
|
|
SSL_CONF_cmd(ctx, userparam, uservalue);
|
|
|
|
it will disable SSLv2 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", "-SSLv2");
|
|
|
|
SSLv2 is B<always> disabled and attempt to override this by the user are
|
|
ignored.
|
|
|
|
By checking the return code of SSL_CTX_cmd() it is possible to query if a
|
|
given B<cmd> is recognised, this is useful is SSL_CTX_cmd() values are
|
|
mixed with additional application specific operations.
|
|
|
|
For example an application might call SSL_CTX_cmd() and if it returns
|
|
-2 (unrecognised command) continue with processing of application specific
|
|
commands.
|
|
|
|
Applications can also use SSL_CTX_cmd() to process command lines though the
|
|
utility function SSL_CTX_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<cmd> and the
|
|
following argument to B<value> (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_CTX_cmd(). If -2 is
|
|
returned then B<cmd> 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<SSL_CONF_TYPE_FILE> an application could translate a relative
|
|
pathname to an absolute pathname.
|
|
|
|
=head1 EXAMPLES
|
|
|
|
Set supported signature algorithms:
|
|
|
|
SSL_CONF_cmd(ctx, "SignatureAlgorithms", "ECDSA+SHA256:RSA+SHA256:DSA+SHA256");
|
|
|
|
Enable all protocols except SSLv3 and SSLv2:
|
|
|
|
SSL_CONF_cmd(ctx, "Protocol", "ALL,-SSLv3,-SSLv2");
|
|
|
|
Only enable TLSv1.2:
|
|
|
|
SSL_CONF_cmd(ctx, "Protocol", "-ALL,TLSv1.2");
|
|
|
|
Disable TLS session tickets:
|
|
|
|
SSL_CONF_cmd(ctx, "Options", "-SessionTicket");
|
|
|
|
Set supported curves to P-256, P-384:
|
|
|
|
SSL_CONF_cmd(ctx, "Curves", "P-256:P-384");
|
|
|
|
Set automatic support for any elliptic curve for key exchange:
|
|
|
|
SSL_CONF_cmd(ctx, "ECDHParameters", "Automatic");
|
|
|
|
=head1 RETURN VALUES
|
|
|
|
SSL_CONF_cmd() returns 1 if the value of B<cmd> is recognised and B<value> is
|
|
B<NOT> used and 2 if both B<cmd> and B<value> 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<cmd> is not recognised.
|
|
|
|
A return value of -3 means B<cmd> is recognised and the command requires a
|
|
value but B<value> is NULL.
|
|
|
|
A return code of 0 indicates that both B<cmd> and B<value> are valid but an
|
|
error occurred attempting to perform the operation: for example due to an
|
|
error in the syntax of B<value> in this case the error queue may provide
|
|
additional information.
|
|
|
|
SSL_CONF_finish() returns 1 for success and 0 for failure.
|
|
|
|
=head1 SEE ALSO
|
|
|
|
L<SSL_CONF_CTX_new(3)|SSL_CONF_CTX_new(3)>,
|
|
L<SSL_CONF_CTX_set_flags(3)|SSL_CONF_CTX_set_flags(3)>,
|
|
L<SSL_CONF_CTX_set1_prefix(3)|SSL_CONF_CTX_set1_prefix(3)>,
|
|
L<SSL_CONF_CTX_set_ssl_ctx(3)|SSL_CONF_CTX_set_ssl_ctx(3)>,
|
|
L<SSL_CONF_cmd_argv(3)|SSL_CONF_cmd_argv(3)>
|
|
|
|
=head1 HISTORY
|
|
|
|
SSL_CONF_cmd() was first added to OpenSSL 1.0.2
|
|
|
|
=cut
|