From: Felix Fietkau <nbd@nbd.name>
Date: Thu, 18 Apr 2024 10:42:01 +0000 (+0200)
Subject: mbedtls: handle session tickets for TLS 1.3
X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=60d8fbb5e669db4b85f0ccd9b86744a8355eb2d9;p=project%2Fustream-ssl.git

mbedtls: handle session tickets for TLS 1.3

Store them inside the context in order to handle reconnect

Signed-off-by: Felix Fietkau <nbd@nbd.name>
---

diff --git a/ustream-internal.h b/ustream-internal.h
index f8f28e1..50e105f 100644
--- a/ustream-internal.h
+++ b/ustream-internal.h
@@ -31,6 +31,7 @@ enum ssl_conn_status {
 	U_SSL_OK = 0,
 	U_SSL_PENDING = -1,
 	U_SSL_ERROR = -2,
+	U_SSL_RETRY = -3,
 };
 
 void ustream_set_io(struct ustream_ssl_ctx *ctx, void *ssl, struct ustream *s);
diff --git a/ustream-mbedtls.c b/ustream-mbedtls.c
index ff2c9a9..b671148 100644
--- a/ustream-mbedtls.c
+++ b/ustream-mbedtls.c
@@ -361,6 +361,7 @@ __hidden int __ustream_ssl_set_require_validation(struct ustream_ssl_ctx *ctx, b
 
 __hidden void __ustream_ssl_context_free(struct ustream_ssl_ctx *ctx)
 {
+	free(ctx->session_data);
 #if defined(MBEDTLS_SSL_CACHE_C)
 	mbedtls_ssl_cache_free(&ctx->cache);
 #endif
@@ -378,14 +379,48 @@ static void ustream_ssl_error(struct ustream_ssl *us, int ret)
 	uloop_timeout_set(&us->error_timer, 0);
 }
 
-static bool ssl_do_wait(int ret)
+static void
+__ustream_ssl_save_session(struct ustream_ssl *us)
+{
+	struct ustream_ssl_ctx *ctx = us->ctx;
+	mbedtls_ssl_session sess;
+
+	if (ctx->server)
+		return;
+
+	free(ctx->session_data);
+	ctx->session_data = NULL;
+
+	mbedtls_ssl_session_init(&sess);
+	if (mbedtls_ssl_get_session(us->ssl, &sess) != 0)
+		return;
+
+	mbedtls_ssl_session_save(&sess, NULL, 0, &ctx->session_data_len);
+	ctx->session_data = malloc(ctx->session_data_len);
+	if (mbedtls_ssl_session_save(&sess, ctx->session_data, ctx->session_data_len,
+				     &ctx->session_data_len))
+		ctx->session_data_len = 0;
+	mbedtls_ssl_session_free(&sess);
+}
+
+static int ssl_check_return(struct ustream_ssl *us, int ret)
 {
 	switch(ret) {
 	case MBEDTLS_ERR_SSL_WANT_READ:
 	case MBEDTLS_ERR_SSL_WANT_WRITE:
-		return true;
+		return U_SSL_PENDING;
+	case MBEDTLS_ERR_SSL_RECEIVED_NEW_SESSION_TICKET:
+#ifdef MBEDTLS_ECP_RESTARTABLE
+	case MBEDTLS_ERR_SSL_CRYPTO_IN_PROGRESS:
+#endif
+		__ustream_ssl_save_session(us);
+		return U_SSL_RETRY;
+	case MBEDTLS_ERR_SSL_PEER_CLOSE_NOTIFY:
+	case MBEDTLS_ERR_NET_CONN_RESET:
+		return 0;
 	default:
-		return false;
+		ustream_ssl_error(us, ret);
+		return U_SSL_ERROR;
 	}
 }
 
@@ -424,17 +459,17 @@ __hidden enum ssl_conn_status __ustream_ssl_connect(struct ustream_ssl *us)
 	void *ssl = us->ssl;
 	int r;
 
-	r = mbedtls_ssl_handshake(ssl);
-	if (r == 0) {
-		ustream_ssl_verify_cert(us);
-		return U_SSL_OK;
-	}
+	do {
+		r = mbedtls_ssl_handshake(ssl);
+		if (r == 0) {
+			ustream_ssl_verify_cert(us);
+			return U_SSL_OK;
+		}
 
-	if (ssl_do_wait(r))
-		return U_SSL_PENDING;
+		r = ssl_check_return(us, r);
+	} while (r == U_SSL_RETRY);
 
-	ustream_ssl_error(us, r);
-	return U_SSL_ERROR;
+	return r;
 }
 
 __hidden int __ustream_ssl_write(struct ustream_ssl *us, const char *buf, int len)
@@ -444,12 +479,14 @@ __hidden int __ustream_ssl_write(struct ustream_ssl *us, const char *buf, int le
 
 	while (done != len) {
 		ret = mbedtls_ssl_write(ssl, (const unsigned char *) buf + done, len - done);
-
 		if (ret < 0) {
-			if (ssl_do_wait(ret))
+			ret = ssl_check_return(us, ret);
+			if (ret == U_SSL_RETRY)
+				continue;
+
+			if (ret == U_SSL_PENDING)
 				return done;
 
-			ustream_ssl_error(us, ret);
 			return -1;
 		}
 
@@ -461,18 +498,15 @@ __hidden int __ustream_ssl_write(struct ustream_ssl *us, const char *buf, int le
 
 __hidden int __ustream_ssl_read(struct ustream_ssl *us, char *buf, int len)
 {
-	int ret = mbedtls_ssl_read(us->ssl, (unsigned char *) buf, len);
-
-	if (ret < 0) {
-		if (ssl_do_wait(ret))
-			return U_SSL_PENDING;
+	int ret;
 
-		if (ret == MBEDTLS_ERR_SSL_PEER_CLOSE_NOTIFY)
-			return 0;
+	do {
+		ret = mbedtls_ssl_read(us->ssl, (unsigned char *) buf, len);
+		if (ret >= 0)
+			return ret;
 
-		ustream_ssl_error(us, ret);
-		return U_SSL_ERROR;
-	}
+		ret = ssl_check_return(us, ret);
+	} while (ret == U_SSL_RETRY);
 
 	return ret;
 }
@@ -491,6 +525,7 @@ __hidden void __ustream_ssl_set_debug(struct ustream_ssl_ctx *ctx, int level,
 __hidden void *__ustream_ssl_session_new(struct ustream_ssl_ctx *ctx)
 {
 	mbedtls_ssl_context *ssl;
+	mbedtls_ssl_session sess;
 
 	ssl = calloc(1, sizeof(*ssl));
 	if (!ssl)
@@ -503,6 +538,13 @@ __hidden void *__ustream_ssl_session_new(struct ustream_ssl_ctx *ctx)
 		return NULL;
 	}
 
+	if (!ctx->session_data_len)
+		return ssl;
+
+	mbedtls_ssl_session_init(&sess);
+	if (mbedtls_ssl_session_load(&sess, ctx->session_data, ctx->session_data_len) == 0)
+		mbedtls_ssl_set_session(ssl, &sess);
+
 	return ssl;
 }
 
diff --git a/ustream-mbedtls.h b/ustream-mbedtls.h
index ff907f6..31df680 100644
--- a/ustream-mbedtls.h
+++ b/ustream-mbedtls.h
@@ -43,6 +43,9 @@ struct ustream_ssl_ctx {
 	void *debug_cb_priv;
 	bool server;
 	int *ciphersuites;
+
+	void *session_data;
+	size_t session_data_len;
 };
 
 static inline char *__ustream_ssl_strerror(int error, char *buffer, int len)