Revise EVP_PKEY param handling

We add new functions for getting parameters and discovering the gettable
and settable parameters. We also make EVP_PKEY_CTX_get_signature_md() a
function and implement it in terms of the new functions.

This enables applications to discover the set of parameters that are
supported for a given algorithm implementation.

Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/9753)

2 files changed, 22 insertions, 10 deletions

diff --git a/include/openssl/core_numbers.h b/include/openssl/core_numbers.h
index 35e6056ba1..002582012e 100644
--- a/include/openssl/core_numbers.h
+++ b/include/openssl/core_numbers.h
@@ -389,7 +389,8 @@ OSSL_CORE_MAKE_FUNC(const OSSL_PARAM *, OP_keymgmt_exportkey_types, (void))
 # define OSSL_FUNC_KEYEXCH_SET_PEER                    4
 # define OSSL_FUNC_KEYEXCH_FREECTX                     5
 # define OSSL_FUNC_KEYEXCH_DUPCTX                      6
-# define OSSL_FUNC_KEYEXCH_SET_PARAMS                  7
+# define OSSL_FUNC_KEYEXCH_SET_CTX_PARAMS              7
+# define OSSL_FUNC_KEYEXCH_SETTABLE_CTX_PARAMS         8
 
 OSSL_CORE_MAKE_FUNC(void *, OP_keyexch_newctx, (void *provctx))
 OSSL_CORE_MAKE_FUNC(int, OP_keyexch_init, (void *ctx, void *provkey))
@@ -398,8 +399,10 @@ OSSL_CORE_MAKE_FUNC(int, OP_keyexch_derive, (void *ctx,  unsigned char *secret,
 OSSL_CORE_MAKE_FUNC(int, OP_keyexch_set_peer, (void *ctx, void *provkey))
 OSSL_CORE_MAKE_FUNC(void, OP_keyexch_freectx, (void *ctx))
 OSSL_CORE_MAKE_FUNC(void *, OP_keyexch_dupctx, (void *ctx))
-OSSL_CORE_MAKE_FUNC(int, OP_keyexch_set_params, (void *ctx,
-                                                 const OSSL_PARAM params[]))
+OSSL_CORE_MAKE_FUNC(int, OP_keyexch_set_ctx_params, (void *ctx,
+                                                     const OSSL_PARAM params[]))
+OSSL_CORE_MAKE_FUNC(const OSSL_PARAM *, OP_keyexch_settable_ctx_params,
+                    (void))
 
 /* Signature */
 
@@ -412,7 +415,10 @@ OSSL_CORE_MAKE_FUNC(int, OP_keyexch_set_params, (void *ctx,
 # define OSSL_FUNC_SIGNATURE_VERIFY_RECOVER          7
 # define OSSL_FUNC_SIGNATURE_FREECTX                 8
 # define OSSL_FUNC_SIGNATURE_DUPCTX                  9
-# define OSSL_FUNC_SIGNATURE_SET_PARAMS             10
+# define OSSL_FUNC_SIGNATURE_GET_CTX_PARAMS         10
+# define OSSL_FUNC_SIGNATURE_GETTABLE_CTX_PARAMS    11
+# define OSSL_FUNC_SIGNATURE_SET_CTX_PARAMS         12
+# define OSSL_FUNC_SIGNATURE_SETTABLE_CTX_PARAMS    13
 
 OSSL_CORE_MAKE_FUNC(void *, OP_signature_newctx, (void *provctx))
 OSSL_CORE_MAKE_FUNC(int, OP_signature_sign_init, (void *ctx, void *provkey))
@@ -436,8 +442,14 @@ OSSL_CORE_MAKE_FUNC(int, OP_signature_verify_recover, (void *ctx,
                                                        size_t siglen))
 OSSL_CORE_MAKE_FUNC(void, OP_signature_freectx, (void *ctx))
 OSSL_CORE_MAKE_FUNC(void *, OP_signature_dupctx, (void *ctx))
-OSSL_CORE_MAKE_FUNC(int, OP_signature_set_params, (void *ctx,
-                                                   const OSSL_PARAM params[]))
+OSSL_CORE_MAKE_FUNC(int, OP_signature_get_ctx_params,
+                    (void *ctx, OSSL_PARAM params[]))
+OSSL_CORE_MAKE_FUNC(const OSSL_PARAM *, OP_signature_gettable_ctx_params,
+                    (void))
+OSSL_CORE_MAKE_FUNC(int, OP_signature_set_ctx_params,
+                    (void *ctx, const OSSL_PARAM params[]))
+OSSL_CORE_MAKE_FUNC(const OSSL_PARAM *, OP_signature_settable_ctx_params,
+                    (void))
 
 # ifdef __cplusplus
 }
diff --git a/include/openssl/evp.h b/include/openssl/evp.h
index 2ea8d2799f..69d70e5e9c 100644
--- a/include/openssl/evp.h
+++ b/include/openssl/evp.h
@@ -1337,6 +1337,7 @@ void EVP_PKEY_asn1_set_security_bits(EVP_PKEY_ASN1_METHOD *ameth,
                                      int (*pkey_security_bits) (const EVP_PKEY
                                                                 *pk));
 
+int EVP_PKEY_CTX_get_signature_md(EVP_PKEY_CTX *ctx, const EVP_MD **md);
 int EVP_PKEY_CTX_set_signature_md(EVP_PKEY_CTX *ctx, const EVP_MD *md);
 
 # define EVP_PKEY_OP_UNDEFINED           0
@@ -1364,10 +1365,6 @@ int EVP_PKEY_CTX_set_signature_md(EVP_PKEY_CTX *ctx, const EVP_MD *md);
 # define EVP_PKEY_OP_TYPE_GEN \
                 (EVP_PKEY_OP_PARAMGEN | EVP_PKEY_OP_KEYGEN)
 
-# define  EVP_PKEY_CTX_get_signature_md(ctx, pmd)        \
-                EVP_PKEY_CTX_ctrl(ctx, -1, EVP_PKEY_OP_TYPE_SIG,  \
-                                        EVP_PKEY_CTRL_GET_MD, 0, (void *)(pmd))
-
 # define  EVP_PKEY_CTX_set_mac_key(ctx, key, len)        \
                 EVP_PKEY_CTX_ctrl(ctx, -1, EVP_PKEY_OP_KEYGEN,  \
                                   EVP_PKEY_CTRL_SET_MAC_KEY, len, (void *)(key))
@@ -1427,7 +1424,10 @@ EVP_PKEY_CTX *EVP_PKEY_CTX_new_id(int id, ENGINE *e);
 EVP_PKEY_CTX *EVP_PKEY_CTX_dup(const EVP_PKEY_CTX *ctx);
 void EVP_PKEY_CTX_free(EVP_PKEY_CTX *ctx);
 
+int EVP_PKEY_CTX_get_params(EVP_PKEY_CTX *ctx, OSSL_PARAM *params);
+const OSSL_PARAM *EVP_PKEY_CTX_gettable_params(EVP_PKEY_CTX *ctx);
 int EVP_PKEY_CTX_set_params(EVP_PKEY_CTX *ctx, OSSL_PARAM *params);
+const OSSL_PARAM *EVP_PKEY_CTX_settable_params(EVP_PKEY_CTX *ctx);
 int EVP_PKEY_CTX_ctrl(EVP_PKEY_CTX *ctx, int keytype, int optype,
                       int cmd, int p1, void *p2);
 int EVP_PKEY_CTX_ctrl_str(EVP_PKEY_CTX *ctx, const char *type,