=head1 NAME
SSL_CTX_set1_groups, SSL_CTX_set1_groups_list, SSL_set1_groups,
-SSL_set1_groups_list, SSL_get1_groups, SSL_get_shared_group,
-SSL_CTX_set1_curves, SSL_CTX_set1_curves_list, SSL_set1_curves,
-SSL_set1_curves_list, SSL_get1_curves, SSL_get_shared_curve
+SSL_set1_groups_list, SSL_get1_groups, SSL_get0_iana_groups,
+SSL_get_shared_group, SSL_get_negotiated_group, SSL_CTX_set1_curves,
+SSL_CTX_set1_curves_list, SSL_set1_curves, SSL_set1_curves_list,
+SSL_get1_curves, SSL_get_shared_curve
- EC supported curve functions
=head1 SYNOPSIS
int SSL_set1_groups_list(SSL *ssl, char *list);
int SSL_get1_groups(SSL *ssl, int *groups);
+ int SSL_get0_iana_groups(SSL *ssl, uint16_t **out);
int SSL_get_shared_group(SSL *s, int n);
+ int SSL_get_negotiated_group(SSL *s);
int SSL_CTX_set1_curves(SSL_CTX *ctx, int *clist, int clistlen);
int SSL_CTX_set1_curves_list(SSL_CTX *ctx, char *list);
=head1 DESCRIPTION
For all of the functions below that set the supported groups there must be at
-least one group in the list.
+least one group in the list. A number of these functions identify groups via a
+unique integer NID value. However, support for some groups may be added by
+external providers. In this case there will be no NID assigned for the group.
+When setting such groups applications should use the "list" form of these
+functions (i.e. SSL_CTX_set1_groups_list() and SSL_set1_groups_list).
SSL_CTX_set1_groups() sets the supported groups for B<ctx> to B<glistlen>
groups in the array B<glist>. The array consist of all NIDs of groups in
preference order. For a TLS client the groups are used directly in the
supported groups extension. For a TLS server the groups are used to
-determine the set of shared groups.
+determine the set of shared groups. Currently supported groups for
+B<TLSv1.3> are B<NID_X9_62_prime256v1>, B<NID_secp384r1>, B<NID_secp521r1>,
+B<NID_X25519>, B<NID_X448>, B<NID_brainpoolP256r1tls13>,
+B<NID_brainpoolP384r1tls13>, B<NID_brainpoolP512r1tls13>, B<NID_ffdhe2048>,
+B<NID_ffdhe3072>, B<NID_ffdhe4096>, B<NID_ffdhe6144> and B<NID_ffdhe8192>.
SSL_CTX_set1_groups_list() sets the supported groups for B<ctx> to
-string B<list>. The string is a colon separated list of group NIDs or
-names, for example "P-521:P-384:P-256".
+string B<list>. The string is a colon separated list of group names, for example
+"P-521:P-384:P-256:X25519:ffdhe2048". Currently supported groups for B<TLSv1.3>
+are B<P-256>, B<P-384>, B<P-521>, B<X25519>, B<X448>, B<brainpoolP256r1tls13>,
+B<brainpoolP384r1tls13>, B<brainpoolP512r1tls13>, B<ffdhe2048>, B<ffdhe3072>,
+B<ffdhe4096>, B<ffdhe6144> and B<ffdhe8192>. Support for other groups may be
+added by external providers. If a group name is preceded with the C<?>
+character, it will be ignored if an implementation is missing.
SSL_set1_groups() and SSL_set1_groups_list() are similar except they set
supported groups for the SSL structure B<ssl>.
return the number of groups for memory allocation purposes. The
B<groups> array is in the form of a set of group NIDs in preference
order. It can return zero if the client did not send a supported groups
-extension.
-
-SSL_get_shared_group() returns shared group B<n> for a server-side
-SSL B<ssl>. If B<n> is -1 then the total number of shared groups is
+extension. If a supported group NID is unknown then the value is set to the
+bitwise OR of TLSEXT_nid_unknown (0x1000000) and the id of the group.
+
+SSL_get0_iana_groups() retrieves the list of groups sent by the
+client in the supported_groups extension. The B<*out> array of bytes
+is populated with the host-byte-order representation of the uint16_t group
+identifiers, as assigned by IANA. The group list is returned in the same order
+that was received in the ClientHello. The return value is the number of groups,
+not the number of bytes written.
+
+SSL_get_shared_group() returns the NID of the shared group B<n> for a
+server-side SSL B<ssl>. If B<n> is -1 then the total number of shared groups is
returned, which may be zero. Other than for diagnostic purposes,
most applications will only be interested in the first shared group
so B<n> is normally set to zero. If the value B<n> is out of range,
-NID_undef is returned.
+NID_undef is returned. If the NID for the shared group is unknown then the value
+is set to the bitwise OR of TLSEXT_nid_unknown (0x1000000) and the id of the
+group.
+
+SSL_get_negotiated_group() returns the NID of the negotiated group used for
+the handshake key exchange process. For TLSv1.3 connections this typically
+reflects the state of the current connection, though in the case of PSK-only
+resumption, the returned value will be from a previous connection. For earlier
+TLS versions, when a session has been resumed, it always reflects the group
+used for key exchange during the initial handshake (otherwise it is from the
+current, non-resumption, connection). This can be called by either client or
+server. If the NID for the shared group is unknown then the value is set to the
+bitwise OR of TLSEXT_nid_unknown (0x1000000) and the id of the group.
All these functions are implemented as macros.
SSL_get1_groups() returns the number of groups, which may be zero.
+SSL_get0_iana_groups() returns the number of (uint16_t) groups, which may be zero.
+
SSL_get_shared_group() returns the NID of shared group B<n> or NID_undef if there
is no shared group B<n>; or the total number of shared groups if B<n>
is -1.
When called on a client B<ssl>, SSL_get_shared_group() has no meaning and
returns -1.
+SSL_get_negotiated_group() returns the NID of the negotiated group used for
+key exchange, or NID_undef if there was no negotiated group.
+
=head1 SEE ALSO
+L<ssl(7)>,
L<SSL_CTX_add_extra_chain_cert(3)>
=head1 HISTORY
-The curve functions were first added to OpenSSL 1.0.2. The equivalent group
-functions were first added to OpenSSL 1.1.1.
+The curve functions were added in OpenSSL 1.0.2. The equivalent group
+functions were added in OpenSSL 1.1.1. The SSL_get_negotiated_group() function
+was added in OpenSSL 3.0.0.
+
+Support for ignoring unknown groups in SSL_CTX_set1_groups_list() and
+SSL_set1_groups_list() was added in OpenSSL 3.3.
=head1 COPYRIGHT
-Copyright 2013-2016 The OpenSSL Project Authors. All Rights Reserved.
+Copyright 2013-2024 The OpenSSL Project Authors. All Rights Reserved.
-Licensed under the OpenSSL license (the "License"). You may not use
+Licensed under the Apache License 2.0 (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<https://www.openssl.org/source/license.html>.
projects / openssl.git / blobdiff