1 files changed, 241 insertions, 0 deletions
diff --git a/lib/tls13/certificate_verify.c b/lib/tls13/certificate_verify.c
new file mode 100644
index 0000000..45ff6fa
--- /dev/null
+++ b/lib/tls13/certificate_verify.c
@@ -0,0 +1,241 @@
+/*
+ * Copyright (C) 2017 Red Hat, Inc.
+ *
+ * Author: Nikos Mavrogiannopoulos
+ *
+ * This file is part of GnuTLS.
+ *
+ * The GnuTLS is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * as published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>
+ *
+ */
+
+#include "gnutls_int.h"
+#include "errors.h"
+#include "handshake.h"
+#include "auth/cert.h"
+#include "ext/signature.h"
+#include "algorithms.h"
+#include "tls13-sig.h"
+#include "mbuffers.h"
+#include "tls13/certificate_verify.h"
+
+#define SRV_CTX "TLS 1.3, server CertificateVerify"
+static const gnutls_datum_t srv_ctx = {
+	(void*)SRV_CTX, sizeof(SRV_CTX)-1
+};
+
+#define CLI_CTX "TLS 1.3, client CertificateVerify"
+static const gnutls_datum_t cli_ctx = {
+	(void*)CLI_CTX, sizeof(CLI_CTX)-1
+};
+
+int _gnutls13_recv_certificate_verify(gnutls_session_t session)
+{
+	int ret;
+	gnutls_buffer_st buf;
+	const gnutls_sign_entry_st *se;
+	gnutls_datum_t sig_data;
+	gnutls_certificate_credentials_t cred;
+	unsigned vflags;
+	gnutls_pcert_st peer_cert;
+	cert_auth_info_t info = _gnutls_get_auth_info(session, GNUTLS_CRD_CERTIFICATE);
+	bool server = 0;
+	gnutls_certificate_type_t cert_type;
+
+	memset(&peer_cert, 0, sizeof(peer_cert));
+
+	/* this message is only expected if we have received
+	 * a certificate message */
+	if (!(session->internals.hsk_flags & HSK_CRT_VRFY_EXPECTED))
+		return 0;
+
+	if (session->security_parameters.entity == GNUTLS_SERVER)
+		server = 1;
+
+	cred = (gnutls_certificate_credentials_t)
+		_gnutls_get_cred(session, GNUTLS_CRD_CERTIFICATE);
+	if (unlikely(cred == NULL))
+		return gnutls_assert_val(GNUTLS_E_INSUFFICIENT_CREDENTIALS);
+	if (unlikely(info == NULL))
+		return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
+
+	ret = _gnutls_recv_handshake(session, GNUTLS_HANDSHAKE_CERTIFICATE_VERIFY, 0, &buf);
+	if (ret < 0)
+		return gnutls_assert_val(ret);
+
+	_gnutls_handshake_log("HSK[%p]: Parsing certificate verify\n", session);
+
+	if (buf.length < 2) {
+		gnutls_assert();
+		ret = GNUTLS_E_UNEXPECTED_PACKET_LENGTH;
+		goto cleanup;
+	}
+
+	se = _gnutls_tls_aid_to_sign_entry(buf.data[0], buf.data[1], get_version(session));
+	if (se == NULL) {
+		_gnutls_handshake_log("Found unsupported signature (%d.%d)\n", (int)buf.data[0], (int)buf.data[1]);
+		ret = gnutls_assert_val(GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER);
+		goto cleanup;
+	}
+
+	if (server)
+		gnutls_sign_algorithm_set_client(session, se->id);
+	else
+		gnutls_sign_algorithm_set_server(session, se->id);
+
+	buf.data+=2;
+	buf.length-=2;
+
+	/* we check during verification whether the algorithm is enabled */
+
+	ret = _gnutls_buffer_pop_datum_prefix16(&buf, &sig_data);
+	if (ret < 0) {
+		gnutls_assert();
+		goto cleanup;
+	}
+
+	if (sig_data.size == 0) {
+		gnutls_assert();
+		ret = GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER;
+		goto cleanup;
+	}
+
+	/* We verify the certificate of the peer. Therefore we need to
+	 * retrieve the negotiated certificate type for the peer. */
+	cert_type = get_certificate_type(session, GNUTLS_CTYPE_PEERS);
+
+	/* Verify the signature */
+	ret = _gnutls_get_auth_info_pcert(&peer_cert, cert_type, info);
+	if (ret < 0) {
+		gnutls_assert();
+		goto cleanup;
+	}
+
+	vflags = cred->verify_flags | session->internals.additional_verify_flags;
+
+	ret = _gnutls13_handshake_verify_data(session, vflags, &peer_cert,
+					      server?(&cli_ctx):(&srv_ctx),
+					      &sig_data, se);
+	if (ret < 0) {
+		gnutls_assert();
+		goto cleanup;
+	}
+
+	if (buf.length > 0) {
+		gnutls_assert();
+		ret = GNUTLS_E_UNEXPECTED_PACKET_LENGTH;
+		goto cleanup;
+	}
+
+	ret = 0;
+ cleanup:
+	gnutls_pcert_deinit(&peer_cert);
+	_gnutls_buffer_clear(&buf);
+	return ret;
+}
+
+int _gnutls13_send_certificate_verify(gnutls_session_t session, unsigned again)
+{
+	int ret;
+	gnutls_pcert_st *apr_cert_list;
+	gnutls_privkey_t apr_pkey;
+	int apr_cert_list_length;
+	mbuffer_st *bufel = NULL;
+	gnutls_buffer_st buf;
+	gnutls_datum_t sig = {NULL, 0};
+	gnutls_sign_algorithm_t algo;
+	const gnutls_sign_entry_st *se;
+	bool server = 0;
+
+	if (again == 0) {
+		if (!session->internals.initial_negotiation_completed &&
+		    session->internals.hsk_flags & HSK_PSK_SELECTED)
+			return 0;
+
+		if (session->security_parameters.entity == GNUTLS_SERVER &&
+		    session->internals.resumed)
+			return 0;
+
+		if (session->security_parameters.entity == GNUTLS_SERVER)
+			server = 1;
+
+		ret = _gnutls_get_selected_cert(session, &apr_cert_list,
+						&apr_cert_list_length, &apr_pkey);
+		if (ret < 0)
+			return gnutls_assert_val(ret);
+
+		if (apr_cert_list_length == 0) {
+			if (server) {
+				return gnutls_assert_val(GNUTLS_E_INSUFFICIENT_CREDENTIALS);
+			} else {
+				/* for client, this means either we
+				 * didn't get a cert request or we are
+				 * declining authentication; in either
+				 * case we don't send a cert verify */
+				return 0;
+			}
+		}
+
+		if (server) {
+			algo = _gnutls_session_get_sign_algo(session, &apr_cert_list[0], apr_pkey, 0, GNUTLS_KX_UNKNOWN);
+			if (algo == GNUTLS_SIGN_UNKNOWN)
+				return gnutls_assert_val(GNUTLS_E_INCOMPATIBLE_SIG_WITH_KEY);
+
+			gnutls_sign_algorithm_set_server(session, algo);
+		} else {
+			/* for client, signature algorithm is already
+			 * determined from Certificate Request */
+			algo = gnutls_sign_algorithm_get_client(session);
+			if (unlikely(algo == GNUTLS_SIGN_UNKNOWN))
+				return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
+		}
+
+		se = _gnutls_sign_to_entry(algo);
+
+		ret = _gnutls13_handshake_sign_data(session, &apr_cert_list[0], apr_pkey,
+						    server?(&srv_ctx):(&cli_ctx),
+						    &sig, se);
+		if (ret < 0)
+			return gnutls_assert_val(ret);
+
+		ret = _gnutls_buffer_init_handshake_mbuffer(&buf);
+		if (ret < 0) {
+			gnutls_assert();
+			goto cleanup;
+		}
+
+		ret = _gnutls_buffer_append_data(&buf, se->aid.id, 2);
+		if (ret < 0) {
+			gnutls_assert();
+			goto cleanup;
+		}
+
+		ret = _gnutls_buffer_append_data_prefix(&buf, 16, sig.data, sig.size);
+		if (ret < 0) {
+			gnutls_assert();
+			goto cleanup;
+		}
+
+		bufel = _gnutls_buffer_to_mbuffer(&buf);
+
+		gnutls_free(sig.data);
+	}
+
+	return _gnutls_send_handshake(session, bufel, GNUTLS_HANDSHAKE_CERTIFICATE_VERIFY);
+
+ cleanup:
+	gnutls_free(sig.data);
+	_gnutls_buffer_clear(&buf);
+	return ret;
+}