Add translation for ECX group parameter

Legacy EVP_PKEY_CTX objects did not support the "group" parameter for X25519
and X448.  The translation of this parameter resulted in an error.  This
caused errors for legacy keys and engines.

Fix this situation by adding a translation that simply checks that the correct
parameter is to be set, but does not actually set anything.  This is correct
since the group name is anyway optional for these two curves.

Fixes #19313

Signed-off-by: Juergen Christ <jchrist@linux.ibm.com>

Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Paul Dale <pauli@openssl.org>
Reviewed-by: Hugo Landau <hlandau@openssl.org>
(Merged from #19348)

crypto/evp/ctrl_params_translate.c

@@ -1953,6 +1953,32 @@ IMPL_GET_RSA_PAYLOAD_COEFFICIENT(7)
 IMPL_GET_RSA_PAYLOAD_COEFFICIENT(8)
 IMPL_GET_RSA_PAYLOAD_COEFFICIENT(9)
 
+static int fix_group_ecx(enum state state,
+                         const struct translation_st *translation,
+                         struct translation_ctx_st *ctx)
+{
+    const char *value = NULL;
+
+    switch (state) {
+    case PRE_PARAMS_TO_CTRL:
+        if (!EVP_PKEY_CTX_IS_GEN_OP(ctx->pctx))
+            return 0;
+        ctx->action_type = NONE;
+        return 1;
+    case POST_PARAMS_TO_CTRL:
+        if (OSSL_PARAM_get_utf8_string_ptr(ctx->params, &value) == 0 ||
+            OPENSSL_strcasecmp(ctx->pctx->keytype, value) != 0) {
+            ERR_raise(ERR_LIB_EVP, ERR_R_PASSED_INVALID_ARGUMENT);
+            ctx->p1 = 0;
+            return 0;
+        }
+        ctx->p1 = 1;
+        return 1;
+    default:
+        return 0;
+    }
+}
+
 /*-
  * The translation table itself
  * ============================
@@ -2272,6 +2298,15 @@ static const struct translation_st evp_pkey_ctx_translations[] = {
     { GET, -1, -1, EVP_PKEY_OP_TYPE_SIG,
       EVP_PKEY_CTRL_GET_MD, NULL, NULL,
       OSSL_SIGNATURE_PARAM_DIGEST, OSSL_PARAM_UTF8_STRING, fix_md },
+
+    /*-
+     * ECX
+     * ===
+     */
+    { SET, EVP_PKEY_X25519, EVP_PKEY_X25519, EVP_PKEY_OP_KEYGEN, -1, NULL, NULL,
+      OSSL_PKEY_PARAM_GROUP_NAME, OSSL_PARAM_UTF8_STRING, fix_group_ecx },
+    { SET, EVP_PKEY_X448, EVP_PKEY_X448, EVP_PKEY_OP_KEYGEN, -1, NULL, NULL,
+      OSSL_PKEY_PARAM_GROUP_NAME, OSSL_PARAM_UTF8_STRING, fix_group_ecx },
 };
 
 static const struct translation_st evp_pkey_translations[] = {
@@ -2690,7 +2725,7 @@ static int evp_pkey_ctx_setget_params_to_ctrl(EVP_PKEY_CTX *pctx,
 
         ret = fixup(PRE_PARAMS_TO_CTRL, translation, &ctx);
 
-        if (ret > 0 && action_type != NONE)
+        if (ret > 0 && ctx.action_type != NONE)
             ret = EVP_PKEY_CTX_ctrl(pctx, keytype, optype,
                                     ctx.ctrl_cmd, ctx.p1, ctx.p2);