signature-params: Add helpers to parse/build ASN.1 algorithmIdentifier for signature schemes

src/libstrongswan/credentials/keys/signature_params.c

@@ -159,6 +159,70 @@ void signature_params_clear(signature_params_t *this)
 	}
 }
 
+/*
+ * Described in header
+ */
+bool signature_params_parse(chunk_t asn1, int level0,
+							signature_params_t *params)
+{
+	chunk_t parameters = chunk_empty;
+	int oid;
+
+	oid = asn1_parse_algorithmIdentifier(asn1, level0, &parameters);
+	params->scheme = signature_scheme_from_oid(oid);
+	switch (params->scheme)
+	{
+		case SIGN_UNKNOWN:
+			return FALSE;
+		case SIGN_RSA_EMSA_PSS:
+		{
+			rsa_pss_params_t *pss = malloc_thing(rsa_pss_params_t);
+
+			if (!rsa_pss_params_parse(parameters, level0+1, pss))
+			{
+				DBG1(DBG_IKE, "failed parsing RSASSA-PSS parameters");
+				free(pss);
+				return FALSE;
+			}
+			params->params = pss;
+			break;
+		}
+		default:
+			params->params = NULL;
+			break;
+	}
+	return TRUE;
+}
+
+/*
+ * Described in header
+ */
+bool signature_params_build(signature_params_t *params, chunk_t *asn1)
+{
+	chunk_t parameters = chunk_empty;
+	int oid;
+
+	oid = signature_scheme_to_oid(params->scheme);
+	if (oid == OID_UNKNOWN)
+	{
+		return FALSE;
+	}
+	if (params->scheme == SIGN_RSA_EMSA_PSS &&
+		!rsa_pss_params_build(params->params, &parameters))
+	{
+		return FALSE;
+	}
+	if (parameters.len)
+	{
+		*asn1 = asn1_algorithmIdentifier_params(oid, parameters);
+	}
+	else
+	{
+		*asn1 = asn1_algorithmIdentifier(oid);
+	}
+	return TRUE;
+}
+
 /**
  * ASN.1 definition of RSASSA-PSS-params
  */

src/libstrongswan/credentials/keys/signature_params.h

@@ -71,6 +71,27 @@ void signature_params_destroy(signature_params_t *this);
  */
 void signature_params_clear(signature_params_t *this);
 
+/**
+ * Parse an ASN.1 algorithmIdentifier with parameters denoting a signature
+ * scheme.
+ *
+ * @param asn1		ASN.1 encoded RSASSA-PSS-params
+ * @param level0	current level of the ASN.1 parser
+ * @param params	parsed parameters
+ * @return			TRUE if successfully parsed
+ */
+bool signature_params_parse(chunk_t asn1, int level0,
+							signature_params_t *params);
+
+/**
+ * Build ASN.1 algorithmIdentifier with parameters denoting a signature scheme.
+ *
+ * @param params	signature scheme and parameters to encode
+ * @param asn1		ASN.1 encoded algorithmIdentifier (allocated)
+ * @return			TRUE if successfully built
+ */
+bool signature_params_build(signature_params_t *params, chunk_t *asn1);
+
 /**
  * Parameters for SIGN_RSA_EMSA_PSS signature scheme
  */

src/libstrongswan/tests/suites/test_signature_params.c

@@ -314,6 +314,105 @@ START_TEST(test_params_clear_null)
 }
 END_TEST
 
+START_TEST(test_params_parse_rsa_pss)
+{
+	signature_params_t parsed, res = { .scheme = SIGN_RSA_EMSA_PSS, };
+
+	ck_assert(signature_params_parse(rsa_pss_parse_tests[_i].aid, 0, &parsed));
+	res.params = &rsa_pss_parse_tests[_i].params;
+	ck_assert(signature_params_equal(&parsed, &res));
+	signature_params_clear(&parsed);
+}
+END_TEST
+
+START_TEST(test_params_parse_rsa_pss_invalid)
+{
+	signature_params_t parsed;
+
+	ck_assert(!signature_params_parse(rsa_pss_parse_invalid_tests[_i], 0, &parsed));
+}
+END_TEST
+
+static struct {
+	bool valid;
+	chunk_t aid;
+	signature_params_t params;
+} params_parse_tests[] = {
+	{ TRUE, chunk_from_chars(0x30,0x0d,0x06,0x09,0x2a,0x86,0x48,0x86,0xf7,0x0d,0x01,0x01,0x0b,0x05,0x00),
+	  { .scheme = SIGN_RSA_EMSA_PKCS1_SHA2_256, }},
+	{ TRUE, chunk_from_chars(0x30,0x0a,0x06,0x08,0x2a,0x86,0x48,0xce,0x3d,0x04,0x03,0x02),
+	  { .scheme = SIGN_ECDSA_WITH_SHA256_DER, }},
+	{ FALSE, chunk_from_chars(0x30,0x0a,0x06,0x08,0x2a,0x86,0x48,0xce,0x3d,0x04,0x03,0xff), },
+};
+
+START_TEST(test_params_parse_other)
+{
+	signature_params_t parsed;
+
+	if (params_parse_tests[_i].valid)
+	{
+		ck_assert(signature_params_parse(params_parse_tests[_i].aid, 0, &parsed));
+		ck_assert(signature_params_equal(&parsed, &params_parse_tests[_i].params));
+		signature_params_clear(&parsed);
+	}
+	else
+	{
+		ck_assert(!signature_params_parse(params_parse_tests[_i].aid, 0, &parsed));
+	}
+}
+END_TEST
+
+START_TEST(test_params_build_rsa_pss)
+{
+	signature_params_t scheme = { .scheme = SIGN_RSA_EMSA_PSS, };
+	chunk_t aid;
+
+	scheme.params = &rsa_pss_build_tests[_i].params;
+	ck_assert(signature_params_build(&scheme, &aid));
+	ck_assert_chunk_eq(rsa_pss_build_tests[_i].aid, aid);
+	chunk_free(&aid);
+}
+END_TEST
+
+START_TEST(test_params_build_rsa_pss_invalid)
+{
+	signature_params_t scheme = { .scheme = SIGN_RSA_EMSA_PSS, };
+	chunk_t aid;
+
+	scheme.params = &rsa_pss_build_invalid_tests[_i];
+	ck_assert(!signature_params_build(&scheme, &aid));
+}
+END_TEST
+
+static struct {
+	bool valid;
+	signature_params_t params;
+	chunk_t aid;
+} params_build_tests[] = {
+	{ TRUE, { .scheme = SIGN_RSA_EMSA_PKCS1_SHA2_256, },
+		chunk_from_chars(0x30,0x0d,0x06,0x09,0x2a,0x86,0x48,0x86,0xf7,0x0d,0x01,0x01,0x0b,0x05,0x00), },
+	{ TRUE, { .scheme = SIGN_ECDSA_WITH_SHA256_DER, },
+		chunk_from_chars(0x30,0x0a,0x06,0x08,0x2a,0x86,0x48,0xce,0x3d,0x04,0x03,0x02), },
+	{ FALSE, { .scheme = SIGN_UNKNOWN, }, },
+};
+
+START_TEST(test_params_build_other)
+{
+	chunk_t aid;
+
+	if (params_build_tests[_i].valid)
+	{
+		ck_assert(signature_params_build(&params_build_tests[_i].params, &aid));
+		ck_assert_chunk_eq(params_build_tests[_i].aid, aid);
+		chunk_free(&aid);
+	}
+	else
+	{
+		ck_assert(!signature_params_build(&params_build_tests[_i].params, &aid));
+	}
+}
+END_TEST
+
 Suite *signature_params_suite_create()
 {
 	Suite *s;
@@ -346,5 +445,17 @@ Suite *signature_params_suite_create()
 	tcase_add_test(tc, test_params_clear_null);
 	suite_add_tcase(s, tc);
 
+	tc = tcase_create("parse");
+	tcase_add_loop_test(tc, test_params_parse_rsa_pss, 0, countof(rsa_pss_parse_tests));
+	tcase_add_loop_test(tc, test_params_parse_rsa_pss_invalid, 0, countof(rsa_pss_parse_invalid_tests));
+	tcase_add_loop_test(tc, test_params_parse_other, 0, countof(params_parse_tests));
+	suite_add_tcase(s, tc);
+
+	tc = tcase_create("build");
+	tcase_add_loop_test(tc, test_params_build_rsa_pss, 0, countof(rsa_pss_build_tests));
+	tcase_add_loop_test(tc, test_params_build_rsa_pss_invalid, 0, countof(rsa_pss_build_invalid_tests));
+	tcase_add_loop_test(tc, test_params_build_other, 0, countof(params_build_tests));
+	suite_add_tcase(s, tc);
+
 	return s;
 }