OpenSSL::PKey.from_parameters for generating PKey objects from parameter values

Author: anakinj

ext/openssl/ossl_pkey.c

@@ -446,6 +446,174 @@ pkey_generate(int argc, VALUE *argv, VALUE self, int genparam)
     return ossl_pkey_new(gen_arg.pkey);
 }
 
+#if OSSL_OPENSSL_PREREQ(3, 0, 0)
+#include <openssl/param_build.h>
+#include <openssl/core_names.h>
+
+struct pkey_from_parameters_alias {
+    char alias[10];
+    char param_name[20];
+};
+
+static const struct pkey_from_parameters_alias rsa_aliases[] = {
+    { "p",    OSSL_PKEY_PARAM_RSA_FACTOR1 },
+    { "q",    OSSL_PKEY_PARAM_RSA_FACTOR2 },
+    { "dmp1", OSSL_PKEY_PARAM_RSA_EXPONENT1 },
+    { "dmq1", OSSL_PKEY_PARAM_RSA_EXPONENT2 },
+    { "iqmp", OSSL_PKEY_PARAM_RSA_COEFFICIENT1 },
+    { "", "" }
+};
+
+static const struct pkey_from_parameters_alias fcc_aliases[] = {
+    { "pub_key",  OSSL_PKEY_PARAM_PUB_KEY },
+    { "priv_key", OSSL_PKEY_PARAM_PRIV_KEY },
+    { "", "" }
+};
+
+struct pkey_from_parameters_arg {
+    OSSL_PARAM_BLD *param_bld;
+    const OSSL_PARAM *settable_params;
+    const struct pkey_from_parameters_alias *aliases;
+};
+
+static int
+add_parameter_to_builder(VALUE key, VALUE value, VALUE arg) {
+    if(NIL_P(value))
+        return ST_CONTINUE;
+
+    if (SYMBOL_P(key))
+        key = rb_sym2str(key);
+
+    const char *key_ptr = StringValueCStr(key);
+    const struct pkey_from_parameters_arg *params = (const struct pkey_from_parameters_arg *) arg;
+
+    for(int i = 0; strlen(params->aliases[i].alias) > 0; i++) {
+        if(strcmp(params->aliases[i].alias, key_ptr) == 0) {
+            key_ptr = params->aliases[i].param_name;
+            break;
+        }
+    }
+
+    for (const OSSL_PARAM *settable_params = params->settable_params; settable_params->key != NULL; settable_params++) {
+        if(strcmp(settable_params->key, key_ptr) == 0) {
+            switch (settable_params->data_type) {
+            case OSSL_PARAM_INTEGER:
+            case OSSL_PARAM_UNSIGNED_INTEGER:
+                if(!OSSL_PARAM_BLD_push_BN(params->param_bld, key_ptr, GetBNPtr(value))) {
+                    OSSL_PARAM_BLD_free(params->param_bld);
+                    ossl_raise(ePKeyError, "OSSL_PARAM_BLD_push_BN");
+                }
+                break;
+            case OSSL_PARAM_UTF8_STRING:
+                StringValue(value);
+                if(!OSSL_PARAM_BLD_push_utf8_string(params->param_bld, key_ptr, RSTRING_PTR(value), RSTRING_LENINT(value))) {
+                    OSSL_PARAM_BLD_free(params->param_bld);
+                    ossl_raise(ePKeyError, "OSSL_PARAM_BLD_push_utf8_string");
+                }
+                break;
+
+            case OSSL_PARAM_OCTET_STRING:
+                StringValue(value);
+                if(!OSSL_PARAM_BLD_push_octet_string(params->param_bld, key_ptr, RSTRING_PTR(value), RSTRING_LENINT(value))) {
+                    OSSL_PARAM_BLD_free(params->param_bld);
+                    ossl_raise(ePKeyError, "OSSL_PARAM_BLD_push_octet_string");
+                }
+                break;
+            case OSSL_PARAM_UTF8_PTR:
+            case OSSL_PARAM_OCTET_PTR:
+                OSSL_PARAM_BLD_free(params->param_bld);
+                ossl_raise(ePKeyError, "Unsupported parameter \"%s\", handling of OSSL_PARAM_UTF8_PTR and OSSL_PARAM_OCTET_PTR not implemented", key_ptr);
+                break;
+            }
+
+            return ST_CONTINUE;
+        }
+    }
+    OSSL_PARAM_BLD_free(params->param_bld);
+
+    char message_buffer[512] = { 0 };
+    char *cur = message_buffer;
+    char *end = message_buffer + sizeof(message_buffer);
+    for (const OSSL_PARAM *settable_params = params->settable_params; settable_params->key != NULL; settable_params++) {
+        const char *fmt = cur == message_buffer ? "%s" : ", %s";
+        if (cur > end)
+            break;
+        cur += snprintf(cur, end-cur, fmt, settable_params->key);
+    }
+
+    for(int i = 0; strlen(params->aliases[i].alias) > 0; i++) {
+        const char *fmt = cur == message_buffer ? "%s" : ", %s";
+        if (cur > end)
+            break;
+        cur += snprintf(cur, end-cur, fmt, params->aliases[i].alias);
+    }
+
+    ossl_raise(ePKeyError, "Invalid parameter \"%s\". Supported parameters: \"%s\"", key_ptr, message_buffer);
+}
+
+static VALUE
+pkey_from_parameters(int argc, VALUE *argv, VALUE self)
+{
+    VALUE alg, options;
+    rb_scan_args(argc, argv, "11", &alg, &options);
+
+    const char* algorithm = StringValueCStr(alg);
+
+    EVP_PKEY_CTX *ctx = EVP_PKEY_CTX_new_from_name(NULL, algorithm, NULL);
+
+    if (ctx == NULL)
+        ossl_raise(ePKeyError, "EVP_PKEY_CTX_new_from_name");
+
+    struct pkey_from_parameters_arg from_params_args = { 0 };
+
+    from_params_args.param_bld = OSSL_PARAM_BLD_new();
+
+    if (from_params_args.param_bld == NULL) {
+        EVP_PKEY_CTX_free(ctx);
+        ossl_raise(ePKeyError, "OSSL_PARAM_BLD_new");
+    }
+
+    from_params_args.settable_params = EVP_PKEY_fromdata_settable(ctx, EVP_PKEY_KEYPAIR);
+
+    if (from_params_args.settable_params == NULL) {
+        EVP_PKEY_CTX_free(ctx);
+        ossl_raise(ePKeyError, "EVP_PKEY_fromdata_settable");
+    }
+
+    if (strcmp("RSA", algorithm) == 0)
+        from_params_args.aliases = rsa_aliases;
+    else
+        from_params_args.aliases = fcc_aliases;
+
+    rb_hash_foreach(options, &add_parameter_to_builder, (VALUE) &from_params_args);
+
+    OSSL_PARAM *params = OSSL_PARAM_BLD_to_param(from_params_args.param_bld);
+    OSSL_PARAM_BLD_free(from_params_args.param_bld);
+
+    if (params == NULL) {
+        EVP_PKEY_CTX_free(ctx);
+        ossl_raise(ePKeyError, "OSSL_PARAM_BLD_to_param");
+    }
+
+    EVP_PKEY *pkey = NULL;
+
+    if (EVP_PKEY_fromdata_init(ctx) <= 0) {
+        EVP_PKEY_CTX_free(ctx);
+        ossl_raise(ePKeyError, "EVP_PKEY_fromdata_init");
+    }
+
+    if (EVP_PKEY_fromdata(ctx, &pkey, EVP_PKEY_KEYPAIR, params) <= 0) {
+        EVP_PKEY_CTX_free(ctx);
+        EVP_PKEY_free(pkey);
+        ossl_raise(ePKeyError, "EVP_PKEY_fromdata");
+    }
+
+    EVP_PKEY_CTX_free(ctx);
+
+    return ossl_pkey_new(pkey);
+}
+#endif
+
 /*
  * call-seq:
  *    OpenSSL::PKey.generate_parameters(algo_name [, options]) -> pkey
@@ -498,6 +666,33 @@ ossl_pkey_s_generate_key(int argc, VALUE *argv, VALUE self)
     return pkey_generate(argc, argv, self, 0);
 }
 
+/*
+ * call-seq:
+ *    OpenSSL::PKey.from_parameters(algo_name, parameters) -> pkey
+ *
+ * Generates a new key based on given key parameters.
+ * NOTE: Requires OpenSSL 3.0 or later.
+ *
+ * The first parameter is the type of the key to create, given as a String, for example RSA, DSA, EC etc.
+ * Second parameter is the parameters to be used for the key.
+ *
+ * For details algorithms and parameters see https://www.openssl.org/docs/man3.0/man3/EVP_PKEY_fromdata.html
+ *
+ * == Example
+ *   pkey = OpenSSL::PKey.from_parameters("RSA", n: 3161751493, e: 65537, d: 2064855961)
+ *   pkey.private? #=> true
+ *   pkey.public_key #=> #<OpenSSL::PKey::RSA...
+ */
+static VALUE
+ossl_pkey_s_from_parameters(int argc, VALUE *argv, VALUE self)
+{
+    #if OSSL_OPENSSL_PREREQ(3, 0, 0)
+    return pkey_from_parameters(argc, argv, self);
+    #else
+    rb_raise(ePKeyError, "OpenSSL::PKey.from_parameters requires OpenSSL 3.0 or later");
+    #endif
+}
+
 /*
  * TODO: There is no convenient way to check the presence of public key
  * components on OpenSSL 3.0. But since keys are immutable on 3.0, pkeys without
@@ -1751,6 +1946,8 @@ Init_ossl_pkey(void)
     rb_define_module_function(mPKey, "read", ossl_pkey_new_from_data, -1);
     rb_define_module_function(mPKey, "generate_parameters", ossl_pkey_s_generate_parameters, -1);
     rb_define_module_function(mPKey, "generate_key", ossl_pkey_s_generate_key, -1);
+    rb_define_module_function(mPKey, "from_parameters", ossl_pkey_s_from_parameters, -1);
+
 #ifdef HAVE_EVP_PKEY_NEW_RAW_PRIVATE_KEY
     rb_define_module_function(mPKey, "new_raw_private_key", ossl_pkey_new_raw_private_key, 2);
     rb_define_module_function(mPKey, "new_raw_public_key", ossl_pkey_new_raw_public_key, 2);