=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 2013-2018 The OpenSSL Project Authors. All Rights Reserved.
+Copyright 2013-2024 The OpenSSL Project Authors. All Rights Reserved.
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
projects / openssl.git / blobdiff