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/*
* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License").
* You may not use this file except in compliance with the License.
* A copy of the License is located at
*
* http://aws.amazon.com/apache2.0
*
* or in the "license" file accompanying this file. This file is distributed
* on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
* express or implied. See the License for the specific language governing
* permissions and limitations under the License.
*/
#include "crypto/s2n_ecdsa.h"
#include "crypto/s2n_fips.h"
#include "crypto/s2n_rsa_pss.h"
#include "error/s2n_errno.h"
#include "s2n_test.h"
#include "testlib/s2n_testlib.h"
#include "tls/s2n_cipher_suites.h"
#include "tls/s2n_tls.h"
#include "tls/s2n_tls13.h"
#include "tls/s2n_tls13_certificate_verify.c"
uint8_t hello[] = "Hello, World!\n";
uint8_t goodbye[] = "Goodbye, World!\n";
struct s2n_tls13_cert_verify_test {
const char *const cert_file;
const char *const key_file;
const struct s2n_signature_scheme *sig_scheme;
const struct s2n_signature_scheme *with_wrong_hash;
};
const struct s2n_tls13_cert_verify_test test_cases[] = {
{
.cert_file = S2N_ECDSA_P256_PKCS1_CERT_CHAIN,
.key_file = S2N_ECDSA_P256_PKCS1_KEY,
.sig_scheme = &s2n_ecdsa_sha256,
.with_wrong_hash = &s2n_ecdsa_sha384,
},
#if RSA_PSS_CERTS_SUPPORTED
{
.cert_file = S2N_RSA_PSS_2048_SHA256_LEAF_CERT,
.key_file = S2N_RSA_PSS_2048_SHA256_LEAF_KEY,
.sig_scheme = &s2n_rsa_pss_pss_sha256,
.with_wrong_hash = &s2n_rsa_pss_pss_sha384,
},
#endif
};
S2N_RESULT s2n_cert_verify_connection_setup_and_send(
struct s2n_connection *sending_conn, struct s2n_connection *verifying_conn,
struct s2n_config *config, struct s2n_cert_chain_and_key *cert_chain,
struct s2n_signature_scheme *sig_scheme, struct s2n_blob *cert)
{
sending_conn->handshake_params.our_chain_and_key = cert_chain;
sending_conn->handshake_params.server_cert_sig_scheme = sig_scheme;
sending_conn->handshake_params.client_cert_sig_scheme = sig_scheme;
sending_conn->secure->cipher_suite = &s2n_tls13_aes_128_gcm_sha256;
sending_conn->actual_protocol_version = S2N_TLS13;
EXPECT_SUCCESS(s2n_connection_set_config(sending_conn, config));
verifying_conn->secure->cipher_suite = &s2n_tls13_aes_128_gcm_sha256;
verifying_conn->actual_protocol_version = S2N_TLS13;
EXPECT_SUCCESS(s2n_connection_set_config(verifying_conn, config));
/* Extract public key from certificate and set it for verifying connection */
s2n_pkey_type pkey_type = { 0 };
if (verifying_conn->mode == S2N_CLIENT) {
EXPECT_OK(s2n_asn1der_to_public_key_and_type(&verifying_conn->handshake_params.server_public_key, &pkey_type, cert));
EXPECT_SUCCESS(s2n_pkey_match(&verifying_conn->handshake_params.server_public_key, sending_conn->handshake_params.our_chain_and_key->private_key));
} else {
EXPECT_OK(s2n_asn1der_to_public_key_and_type(&verifying_conn->handshake_params.client_public_key, &pkey_type, cert));
EXPECT_SUCCESS(s2n_pkey_match(&verifying_conn->handshake_params.client_public_key, sending_conn->handshake_params.our_chain_and_key->private_key));
}
/* Hash initialization */
EXPECT_SUCCESS(s2n_hash_init(&sending_conn->handshake.hashes->sha256, S2N_HASH_SHA256));
EXPECT_SUCCESS(s2n_hash_update(&sending_conn->handshake.hashes->sha256, hello, sizeof(hello)));
EXPECT_SUCCESS(s2n_hash_init(&verifying_conn->handshake.hashes->sha256, S2N_HASH_SHA256));
EXPECT_SUCCESS(s2n_hash_update(&verifying_conn->handshake.hashes->sha256, hello, sizeof(hello)));
/* Send cert verify */
EXPECT_SUCCESS(s2n_tls13_cert_verify_send(sending_conn));
EXPECT_SUCCESS(s2n_stuffer_copy(&sending_conn->handshake.io, &verifying_conn->handshake.io,
s2n_stuffer_data_available(&sending_conn->handshake.io)));
return S2N_RESULT_OK;
}
int run_tests(const struct s2n_tls13_cert_verify_test *test_case, s2n_mode verifier_mode)
{
const char *cert_file = test_case->cert_file;
const char *key_file = test_case->key_file;
struct s2n_signature_scheme sig_scheme = *test_case->sig_scheme;
char cert_chain_pem[S2N_MAX_TEST_PEM_SIZE] = { 0 };
char private_key_pem[S2N_MAX_TEST_PEM_SIZE] = { 0 };
EXPECT_SUCCESS(s2n_read_test_pem(cert_file, &cert_chain_pem[0], S2N_MAX_TEST_PEM_SIZE));
EXPECT_SUCCESS(s2n_read_test_pem(key_file, &private_key_pem[0], S2N_MAX_TEST_PEM_SIZE));
DEFER_CLEANUP(struct s2n_cert_chain_and_key *cert_chain = s2n_cert_chain_and_key_new(),
s2n_cert_chain_and_key_ptr_free);
EXPECT_NOT_NULL(cert_chain);
EXPECT_SUCCESS(s2n_cert_chain_and_key_load_pem(cert_chain, cert_chain_pem, private_key_pem));
DEFER_CLEANUP(struct s2n_config *config = s2n_config_new(), s2n_config_ptr_free);
EXPECT_NOT_NULL(config);
EXPECT_SUCCESS(s2n_config_set_cipher_preferences(config, "20200207"));
EXPECT_SUCCESS(s2n_config_add_cert_chain_and_key_to_store(config, cert_chain));
/* Initialize a certificate */
DEFER_CLEANUP(struct s2n_stuffer certificate_in = { 0 }, s2n_stuffer_free);
DEFER_CLEANUP(struct s2n_stuffer certificate_out = { 0 }, s2n_stuffer_free);
EXPECT_SUCCESS(s2n_stuffer_alloc(&certificate_in, S2N_MAX_TEST_PEM_SIZE));
EXPECT_SUCCESS(s2n_stuffer_alloc(&certificate_out, S2N_MAX_TEST_PEM_SIZE));
EXPECT_SUCCESS(s2n_stuffer_write_bytes(&certificate_in, (uint8_t *) cert_chain_pem, sizeof(cert_chain_pem)));
EXPECT_SUCCESS(s2n_stuffer_certificate_from_pem(&certificate_in, &certificate_out));
uint32_t available_size = s2n_stuffer_data_available(&certificate_out);
struct s2n_blob cert = { 0 };
EXPECT_SUCCESS(s2n_blob_init(&cert, s2n_stuffer_raw_read(&certificate_out, available_size), available_size));
/* Successfully send and receive certificate verify */
{
DEFER_CLEANUP(struct s2n_connection *sending_conn = s2n_connection_new(S2N_PEER_MODE(verifier_mode)),
s2n_connection_ptr_free);
EXPECT_NOT_NULL(sending_conn);
DEFER_CLEANUP(struct s2n_connection *verifying_conn = s2n_connection_new(verifier_mode),
s2n_connection_ptr_free);
EXPECT_NOT_NULL(verifying_conn);
EXPECT_OK(s2n_cert_verify_connection_setup_and_send(sending_conn, verifying_conn, config, cert_chain, &sig_scheme, &cert));
/* Receive and verify cert */
EXPECT_SUCCESS(s2n_tls13_cert_verify_recv(verifying_conn));
/* Repeat the above test successfully */
EXPECT_SUCCESS(s2n_tls13_cert_verify_send(sending_conn));
EXPECT_SUCCESS(s2n_stuffer_copy(&sending_conn->handshake.io, &verifying_conn->handshake.io,
s2n_stuffer_data_available(&sending_conn->handshake.io)));
EXPECT_SUCCESS(s2n_tls13_cert_verify_recv(verifying_conn));
/* Test fails if cipher suites hash is configured incorrectly */
verifying_conn->secure->cipher_suite = &s2n_tls13_aes_256_gcm_sha384;
EXPECT_SUCCESS(s2n_tls13_cert_verify_send(sending_conn));
EXPECT_SUCCESS(s2n_stuffer_copy(&sending_conn->handshake.io, &verifying_conn->handshake.io,
s2n_stuffer_data_available(&sending_conn->handshake.io)));
EXPECT_FAILURE_WITH_ERRNO(s2n_tls13_cert_verify_recv(verifying_conn), S2N_ERR_VERIFY_SIGNATURE);
};
/* Verifying connection errors with incorrect signed content */
{
DEFER_CLEANUP(struct s2n_connection *sending_conn = s2n_connection_new(S2N_PEER_MODE(verifier_mode)),
s2n_connection_ptr_free);
EXPECT_NOT_NULL(sending_conn);
DEFER_CLEANUP(struct s2n_connection *verifying_conn = s2n_connection_new(verifier_mode),
s2n_connection_ptr_free);
EXPECT_NOT_NULL(verifying_conn);
EXPECT_OK(s2n_cert_verify_connection_setup_and_send(sending_conn, verifying_conn, config, cert_chain, &sig_scheme, &cert));
/* Update receive hash with goodbye */
EXPECT_SUCCESS(s2n_hash_update(&verifying_conn->handshake.hashes->sha256, goodbye, sizeof(goodbye)));
uint64_t verifying_bytes = 0;
uint64_t sending_bytes = 0;
EXPECT_SUCCESS(s2n_hash_get_currently_in_hash_total(&verifying_conn->handshake.hashes->sha256, &verifying_bytes));
EXPECT_SUCCESS(s2n_hash_get_currently_in_hash_total(&sending_conn->handshake.hashes->sha256, &sending_bytes));
EXPECT_NOT_EQUAL(sending_bytes, verifying_bytes);
EXPECT_FAILURE_WITH_ERRNO(s2n_tls13_cert_verify_recv(verifying_conn), S2N_ERR_VERIFY_SIGNATURE);
};
/* Verifying connection errors with even 1 bit incorrect */
{
DEFER_CLEANUP(struct s2n_connection *sending_conn = s2n_connection_new(S2N_PEER_MODE(verifier_mode)),
s2n_connection_ptr_free);
EXPECT_NOT_NULL(sending_conn);
DEFER_CLEANUP(struct s2n_connection *verifying_conn = s2n_connection_new(verifier_mode),
s2n_connection_ptr_free);
EXPECT_NOT_NULL(verifying_conn);
EXPECT_OK(s2n_cert_verify_connection_setup_and_send(sending_conn, verifying_conn, config, cert_chain, &sig_scheme, &cert));
/* Flip one bit in verifying_conn io buffer */
EXPECT_TRUE(10 < s2n_stuffer_data_available(&verifying_conn->handshake.io));
verifying_conn->handshake.io.blob.data[10] ^= 1;
EXPECT_FAILURE_WITH_ERRNO(s2n_tls13_cert_verify_recv(verifying_conn), S2N_ERR_VERIFY_SIGNATURE);
};
/* Verifying connection errors with wrong hash algorithms */
{
DEFER_CLEANUP(struct s2n_connection *sending_conn = s2n_connection_new(S2N_PEER_MODE(verifier_mode)),
s2n_connection_ptr_free);
EXPECT_NOT_NULL(sending_conn);
DEFER_CLEANUP(struct s2n_connection *verifying_conn = s2n_connection_new(verifier_mode),
s2n_connection_ptr_free);
EXPECT_NOT_NULL(verifying_conn);
EXPECT_OK(s2n_cert_verify_connection_setup_and_send(sending_conn, verifying_conn, config, cert_chain, &sig_scheme, &cert));
/* Use a hash algorithm different from sender by prepending corresponding iana value */
struct s2n_stuffer rereader = verifying_conn->handshake.io;
EXPECT_SUCCESS(s2n_stuffer_rewrite(&rereader));
EXPECT_SUCCESS(s2n_stuffer_write_uint16(&rereader, test_case->with_wrong_hash->iana_value));
EXPECT_FAILURE_WITH_ERRNO(s2n_tls13_cert_verify_recv(verifying_conn), S2N_ERR_VERIFY_SIGNATURE);
};
return 0;
}
int main(int argc, char **argv)
{
BEGIN_TEST();
EXPECT_SUCCESS(s2n_enable_tls13_in_test());
for (size_t i = 0; i < s2n_array_len(test_cases); i++) {
/* Run all tests for server sending and client receiving/verifying cert_verify message */
run_tests(&test_cases[i], S2N_CLIENT);
/* Run all tests for client sending and server receiving/verifying cert_verify message */
run_tests(&test_cases[i], S2N_SERVER);
}
/* Self-talk: Ensure that the signature algorithm used to sign the CertificateVerify message
* is validated against the certificate type
*/
if (s2n_is_tls13_fully_supported()) {
struct s2n_tls13_cert_verify_test test_server_parameters[] = {
{
.cert_file = S2N_RSA_2048_PKCS1_CERT_CHAIN,
.key_file = S2N_RSA_2048_PKCS1_KEY,
.sig_scheme = &s2n_rsa_pss_rsae_sha256,
},
{
.cert_file = S2N_RSA_PSS_2048_SHA256_LEAF_CERT,
.key_file = S2N_RSA_PSS_2048_SHA256_LEAF_KEY,
.sig_scheme = &s2n_rsa_pss_pss_sha256,
},
{
.cert_file = S2N_ECDSA_P256_PKCS1_CERT_CHAIN,
.key_file = S2N_ECDSA_P256_PKCS1_KEY,
.sig_scheme = &s2n_ecdsa_sha256,
}
};
const struct s2n_signature_scheme *test_client_sig_schemes[] = {
&s2n_rsa_pss_rsae_sha256,
&s2n_rsa_pss_pss_sha256,
&s2n_ecdsa_sha256,
};
for (size_t param_idx = 0; param_idx < s2n_array_len(test_server_parameters); param_idx++) {
struct s2n_tls13_cert_verify_test server_parameters = test_server_parameters[param_idx];
DEFER_CLEANUP(struct s2n_cert_chain_and_key *cert_chain = NULL, s2n_cert_chain_and_key_ptr_free);
EXPECT_SUCCESS(s2n_test_cert_chain_and_key_new(&cert_chain, server_parameters.cert_file,
server_parameters.key_file));
DEFER_CLEANUP(struct s2n_config *config = s2n_config_new(), s2n_config_ptr_free);
EXPECT_NOT_NULL(config);
EXPECT_SUCCESS(s2n_config_set_cipher_preferences(config, "test_all_tls13"));
EXPECT_SUCCESS(s2n_config_disable_x509_verification(config));
/* The server only supports the single test certificate. Due to the fallback logic in
* the s2n-tls server, the signature algorithm corresponding with the test certificate
* will always be used to sign the CertificateVerify message, regardless of the
* client's advertised signature schemes.
*/
EXPECT_SUCCESS(s2n_config_add_cert_chain_and_key_to_store(config, cert_chain));
for (size_t sig_idx = 0; sig_idx < s2n_array_len(test_client_sig_schemes); sig_idx++) {
DEFER_CLEANUP(struct s2n_connection *server_conn = s2n_connection_new(S2N_SERVER),
s2n_connection_ptr_free);
EXPECT_NOT_NULL(server_conn);
EXPECT_SUCCESS(s2n_connection_set_blinding(server_conn, S2N_SELF_SERVICE_BLINDING));
EXPECT_SUCCESS(s2n_connection_set_config(server_conn, config));
DEFER_CLEANUP(struct s2n_connection *client_conn = s2n_connection_new(S2N_CLIENT),
s2n_connection_ptr_free);
EXPECT_NOT_NULL(client_conn);
EXPECT_SUCCESS(s2n_connection_set_blinding(client_conn, S2N_SELF_SERVICE_BLINDING));
EXPECT_SUCCESS(s2n_connection_set_config(client_conn, config));
/* The client only supports the single test signature scheme, which allows for the
* server to sign the CertificateVerify message with a signature algorithm that
* isn't supported by the client.
*/
const struct s2n_signature_scheme *client_advertised_sig_scheme = test_client_sig_schemes[sig_idx];
struct s2n_signature_preferences test_sig_preferences = {
.count = 1,
.signature_schemes = &client_advertised_sig_scheme,
};
struct s2n_security_policy client_policy = security_policy_test_all_tls13;
client_policy.signature_preferences = &test_sig_preferences;
client_conn->security_policy_override = &client_policy;
DEFER_CLEANUP(struct s2n_test_io_pair io_pair = { 0 }, s2n_io_pair_close);
EXPECT_SUCCESS(s2n_io_pair_init_non_blocking(&io_pair));
EXPECT_SUCCESS(s2n_connections_set_io_pair(client_conn, server_conn, &io_pair));
/* Send the CertificateVerify message. */
EXPECT_OK(s2n_negotiate_test_server_and_client_until_message(server_conn, client_conn,
SERVER_CERT_VERIFY));
EXPECT_SUCCESS(s2n_stuffer_rewrite(&server_conn->handshake.io));
EXPECT_SUCCESS(s2n_tls13_cert_verify_send(server_conn));
/* Check that the expected signature algorithm was used by the server. */
EXPECT_EQUAL(server_conn->handshake_params.server_cert_sig_scheme, server_parameters.sig_scheme);
/* Overwrite the SignatureScheme field of the CertificateVerify message to lie to the
* client about which signature algorithm was used to sign the signature content. This
* will trick the client into always thinking its advertised signature algorithm was
* used.
*/
struct s2n_stuffer cert_verify_stuffer = server_conn->handshake.io;
EXPECT_SUCCESS(s2n_stuffer_rewrite(&cert_verify_stuffer));
EXPECT_SUCCESS(s2n_stuffer_write_uint16(&cert_verify_stuffer,
client_advertised_sig_scheme->iana_value));
EXPECT_SUCCESS(s2n_stuffer_wipe(&client_conn->handshake.io));
EXPECT_SUCCESS(s2n_stuffer_copy(&server_conn->handshake.io, &client_conn->handshake.io,
s2n_stuffer_data_available(&server_conn->handshake.io)));
int ret = s2n_tls13_cert_verify_recv(client_conn);
if (client_advertised_sig_scheme == server_parameters.sig_scheme) {
/* If the client's advertised signature scheme matches what the server actually
* used to sign the CertificateVerify message, validation should succeed.
*/
EXPECT_SUCCESS(ret);
} else {
/* Otherwise, the client should observe that the indicated signature algorithm
* from the server doesn't match the certificate type, and the connection
* should fail.
*/
EXPECT_FAILURE_WITH_ERRNO(ret, S2N_ERR_INVALID_SIGNATURE_ALGORITHM);
}
}
}
}
END_TEST();
}
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