Latest update.

doc/man7/provider-keyexch.pod

@@ -31,6 +31,8 @@ provider-keyexch - The keyexch library E<lt>-E<gt> provider functions
  /* Key Exchange parameters */
  int OP_keyexch_set_ctx_params(void *ctx, const OSSL_PARAM params[]);
  const OSSL_PARAM *OP_keyexch_settable_ctx_params(void);
+ int OP_keyexch_get_ctx_params(void *ctx, OSSL_PARAM params[]);
+ const OSSL_PARAM *OP_keyexch_gettable_ctx_params(void);
 
 =head1 DESCRIPTION
 
@@ -71,6 +73,8 @@ macros in L<openssl-core_numbers.h(7)>, as follows:
 
  OP_keyexch_set_ctx_params        OSSL_FUNC_KEYEXCH_SET_CTX_PARAMS
  OP_keyexch_settable_ctx_params   OSSL_FUNC_KEYEXCH_SETTABLE_CTX_PARAMS
+ OP_keyexch_get_ctx_params        OSSL_FUNC_KEYEXCH_GET_CTX_PARAMS
+ OP_keyexch_gettable_ctx_params   OSSL_FUNC_KEYEXCH_GETTABLE_CTX_PARAMS
 
 A key exchange algorithm implementation may not implement all of these functions.
 In order to be a consistent set of functions a provider must implement
@@ -123,14 +127,35 @@ The length of the shared secret should be written to I<*secretlen>.
 If I<secret> is NULL then the maximum length of the shared secret should be
 written to I<*secretlen>.
 
+=head2 Key Exchange Parameters Functions
+
+OP_keyexch_set_ctx_params() sets key exchange parameters associated with the
+given provider side key exchange context I<ctx> to I<params>,
+see L</Key Exchange Parameters>.
+Any parameter settings are additional to any that were previously set.
+
+OP_keyexch_get_ctx_params() gets key exchange parameters associated with the
+given provider side key exchange context I<ctx> into I<params>,
+see L</Key Exchange Parameters>.
+
+OP_keyexch_settable_ctx_params() yields a constant B<OSSL_PARAM> array that
+describes the settable parameters, i.e. parameters that can be used with
+OP_signature_set_ctx_params().
+If OP_keyexch_settable_ctx_params() is present, OP_keyexch_set_ctx_params() must
+also be present, and vice versa.
+Similarly, OP_keyexch_gettable_ctx_params() yields a constant B<OSSL_PARAM>
+array that describes the gettable parameters, i.e. parameters that can be
+handled by OP_signature_get_ctx_params().
+If OP_keyexch_gettable_ctx_params() is present, OP_keyexch_get_ctx_params() must
+also be present, and vice versa.
+See L<OSSL_PARAM(3)> for the use of B<OSSL_PARAM> as parameter descriptor.
+
+Notice that not all settable parameters are also gettable, and vice versa.
+
 =head2 Key Exchange Parameters
 
 See L<OSSL_PARAM(3)> for further details on the parameters structure used by
-the OP_keyexch_set_params() function.
-
-OP_keyexch_set_ctx_params() sets key exchange parameters associated with the
-given provider side key exchange context I<ctx> to I<params>.
-Any parameter settings are additional to any that were previously set.
+the OP_keyexch_set_ctx_params() and OP_keyexch_get_ctx_params() functions.
 
 Parameters currently recognised by built-in key exchange algorithms are as
 follows.
@@ -150,20 +175,69 @@ If padding is on then the derived shared secret will have its first bytes filled
 with 0s where necessary to make the shared secret the same size as the largest
 possible secret size.
 
-=back
+=item "ecdh-cofactor-mode" (B<OSSL_EXCHANGE_PARAM_EC_ECDH_COFACTOR_MODE>) <integer>
 
-OP_keyexch_settable_ctx_params() gets a constant B<OSSL_PARAM> array that
-describes the settable parameters, i.e. parameters that can be used with
-OP_signature_set_ctx_params().
-See L<OSSL_PARAM(3)> for the use of B<OSSL_PARAM> as parameter descriptor.
+Sets/gets the ECDH mode of operation for the associated key exchange ctx.
+
+In the context of an Elliptic Curve Diffie-Hellman key exchange, this parameter
+can be used to select between the plain Diffie-Hellman (DH) or Cofactor
+Diffie-Hellman (CDH) variants of the key exchange algorithm.
+
+When setting, the value should be 1, 0 or -1, respectively forcing cofactor mode
+on, off, or resetting it to the default for the private key associated with the
+given key exchange ctx.
+
+When getting, the value should be either 1 or 0, respectively signaling if the
+cofactor mode is on or off.
+
+See also L<provider-keymgmt(7)> for the related
+B<OSSL_PKEY_PARAM_USE_COFACTOR_ECDH> parameter that can be set on a
+per-key basis.
+
+=item "kdf-type" (B<OSSL_EXCHANGE_PARAM_KDF_TYPE>) <utf8_string>
+
+Sets/gets the Key Derivation Function type to apply within the associated key
+exchange ctx.
+
+=item "kdf-digest" (B<OSSL_EXCHANGE_PARAM_KDF_DIGEST>) <utf8_string>
+
+Sets/gets the Digest algorithm to be used as part of the Key Derivation Function
+associated with the given key exchange ctx.
+
+=item "kdf-digest-props" (B<OSSL_EXCHANGE_PARAM_KDF_DIGEST_PROPS>) <utf8_string>
+
+Sets properties to be used upon look up of the implementation for the selected
+Digest algorithm for the Key Derivation Function associated with the given key
+exchange ctx.
+
+=item "kdf-outlen" (B<OSSL_EXCHANGE_PARAM_KDF_OUTLEN>) <size_t>
+
+Sets/gets the desired size for the output of the chosen Key Derivation Function
+associated with the given key exchange ctx.
+
+=item "kdf-ukm" (B<OSSL_EXCHANGE_PARAM_KDF_UKM>) <octet_string>
+
+Sets/gets User Key Material to be used as part of the selected Key Derivation
+Function associated with the given key exchange ctx.
+
+=item "kdf-ukm-len" (B<OSSL_EXCHANGE_PARAM_KDF_UKM_LEN>) <size_t>
+
+Sets/gets the size of the User Key Material to be used as part of the selected
+Key Derivation Function associated with the given key exchange ctx.
+
+=back
 
 =head1 RETURN VALUES
 
 OP_keyexch_newctx() and OP_keyexch_dupctx() should return the newly created
 provider side key exchange context, or NULL on failure.
 
-OP_keyexch_init(), OP_keyexch_set_peer(), OP_keyexch_derive() and
-OP_keyexch_set_params() should return 1 for success or 0 on error.
+OP_keyexch_init(), OP_keyexch_set_peer(), OP_keyexch_derive(),
+OP_keyexch_set_params(), and OP_keyexch_get_params() should return 1 for success
+or 0 on error.
+
+OP_keyexch_settable_ctx_params() and OP_keyexch_gettable_ctx_params() should
+always return a constant B<OSSL_PARAM> array.
 
 =head1 SEE ALSO