From d70bd1f6728e8ac9c32086706e540280de44c588 Mon Sep 17 00:00:00 2001
From: Johannes Bauer <joe@johannes-bauer.com>
Date: Wed, 23 Oct 2019 14:28:42 +0200
Subject: [PATCH] TLS-PSK connection is working in TLSv1.3

Apparently, I need to spell out "-ciphersuites
TLS_CHACHA20_POLY1305_SHA256:TLS_AES_256_GCM_SHA384" in the openssl
s_client command, or it simply will not work.
---
 Makefile  |  2 +-
 openssl.c |  8 +-------
 server.c  | 22 +++++++++++++++++++---
 3 files changed, 21 insertions(+), 11 deletions(-)

diff --git a/Makefile b/Makefile
index d7a2cbd..e037cf6 100644
--- a/Makefile
+++ b/Makefile
@@ -6,7 +6,7 @@ INSTALL_PREFIX := /usr/local/
 CFLAGS := -Wall -Wextra -Wshadow -Wswitch -Wpointer-arith -Wcast-qual -Wstrict-prototypes -Wmissing-prototypes -Werror=implicit-function-declaration -Werror=format -Wno-unused-parameter
 CFLAGS += -O3 -std=c11 -pthread -D_POSIX_SOURCE -D_XOPEN_SOURCE=500 -DBUILD_REVISION='"$(BUILD_REVISION)"'
 CFLAGS += `pkg-config --cflags openssl`
-CFLAGS += -ggdb3 -DDEBUG -fsanitize=address -fsanitize=undefined -fsanitize=leak
+#CFLAGS += -ggdb3 -DDEBUG -fsanitize=address -fsanitize=undefined -fsanitize=leak
 PYPGMOPTS := ../Python/pypgmopts/pypgmopts
 
 LDFLAGS := `pkg-config --libs openssl`
diff --git a/openssl.c b/openssl.c
index 4337043..7881412 100644
--- a/openssl.c
+++ b/openssl.c
@@ -91,21 +91,15 @@ bool create_generic_tls_context(struct generic_tls_ctx_t *gctx, bool server) {
 		return false;
 	}
 
-	/* In the cipher suite we're using, none of these should be used anyways
-	 * (PSK); however for the future we want to have proper crypto here as
-	 * well. */
-#if 0
-	if (!SSL_CTX_set1_sigalgs_list(gctx->ctx, "ECDSA+SHA256:RSA+SHA256:ECDSA+SHA384:RSA+SHA384:ECDSA+SHA512:RSA+SHA512")) {
+	if (!SSL_CTX_set1_sigalgs_list(gctx->ctx, "ed448:ed25519")) {
 		log_openssl(LLVL_FATAL, "Cannot set TLS generic context signature algorithms.");
 		return false;
 	}
-#endif
 
 	if (!SSL_CTX_set1_curves_list(gctx->ctx, "X448:X25519")) {
 		log_openssl(LLVL_FATAL, "Cannot set TLS generic context ECDHE curves.");
 		return false;
 	}
-
 	return true;
 }
 
diff --git a/server.c b/server.c
index 4c31b63..e0f711c 100644
--- a/server.c
+++ b/server.c
@@ -308,9 +308,12 @@ static int psk_server_callback(SSL *ssl, const unsigned char *identity, size_t i
 	fprintf(stderr, "PSK server SSL %p identity %s len %ld sess %p\n", ssl, identity, identity_len, *sessptr);
 	SSL_SESSION *sess = SSL_SESSION_new();
 	SSL_SESSION_set1_master_key(sess, (const unsigned char*)"\x00\x11\x22", 3);
-	SSL_SESSION_set_cipher(sess, SSL_get_pending_cipher(ssl));
-	//const SSL_CIPHER *cipher = SSL_CIPHER_find(ssl, TLS13_AES_256_GCM_SHA384_BYTES);
-	//SSL_SESSION_set_cipher(sess, cipher);
+	const unsigned char tls13_aes128gcmsha256_id[] = { 0x13, 0x01 };
+	const SSL_CIPHER *cipher = SSL_CIPHER_find(ssl, tls13_aes128gcmsha256_id);
+	if (!cipher) {
+		return 0;
+	}
+	SSL_SESSION_set_cipher(sess, cipher);
 	SSL_SESSION_set_protocol_version(sess, TLS1_3_VERSION);
 	*sessptr = sess;
 	return 1;
@@ -331,8 +334,18 @@ static void *client_handler_thread(void *vctx) {
 		ERR_print_errors_fp(stderr);
 	} else {
 		log_msg(LLVL_DEBUG, "Client connected, waiting for data...");
+		while (true) {
+			struct msg_t msg;
+			int rxlen = SSL_read(ssl, &msg, sizeof(msg));
+			if (rxlen != sizeof(msg)) {
+				log_msg(LLVL_WARNING, "Tried to read message of %d bytes, recevied %d. Severing connection to client.", sizeof(msg), rxlen);
+				break;
+			}
+		}
+		fprintf(stderr, "done\n");
 	}
 
+	SSL_free(ssl);
 	shutdown(client->fd, SHUT_RDWR);
 	close(client->fd);
 	free(client);
@@ -348,6 +361,9 @@ bool keyserver_start(const struct pgmopts_server_t *opts) {
 
 	SSL_CTX_set_psk_find_session_callback(gctx.ctx, psk_server_callback);
 
+    if (!SSL_CTX_use_psk_identity_hint(gctx.ctx, "watwatwat")) {
+	}
+
 	int tcp_sock = create_tcp_server_socket(opts->port);
 	if (tcp_sock == -1) {
 		log_msg(LLVL_ERROR, "Cannot start server without server socket.");