Split tls_handshake() out from tls_accept/tls_connect. By doing this the

tls_accept/tls_connect functions can be guaranteed to succeed or fail and
will no longer return TLS_READ_AGAIN/TLS_WRITE_AGAIN. This also resolves
the semantics of tls_accept_*.

The tls_handshake() function now does I/O and can return
TLS_READ_AGAIN/TLS_WRITE_AGAIN. Calls to tls_read() and tls_write() will
trigger the handshake if it has not already completed, meaning that in many
cases existing code will continue to work.

Discussed over many coffees at l2k15.

ok beck@ bluhm@

1 files changed, 46 insertions, 30 deletions

diff --git a/lib/libtls/tls_server.c b/lib/libtls/tls_server.c
index a3cee095962..3dfd29ac19f 100644
--- a/lib/libtls/tls_server.c
+++ b/lib/libtls/tls_server.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: tls_server.c,v 1.14 2015/09/10 09:10:42 jsing Exp $ */
+/* $OpenBSD: tls_server.c,v 1.15 2015/09/10 10:14:20 jsing Exp $ */
 /*
  * Copyright (c) 2014 Joel Sing <jsing@openbsd.org>
  *
@@ -110,54 +110,70 @@ tls_configure_server(struct tls *ctx)
 }
 
 int
+tls_accept_socket(struct tls *ctx, struct tls **cctx, int socket)
+{
+	return (tls_accept_fds(ctx, cctx, socket, socket));
+}
+
+int
 tls_accept_fds(struct tls *ctx, struct tls **cctx, int fd_read, int fd_write)
 {
-	struct tls *conn_ctx = *cctx;
-	int ret, err;
+	struct tls *conn_ctx = NULL;
 	
 	if ((ctx->flags & TLS_SERVER) == 0) {
 		tls_set_errorx(ctx, "not a server context");
 		goto err;
 	}
 
-	if (conn_ctx == NULL) {
-		if ((conn_ctx = tls_server_conn(ctx)) == NULL) {
-			tls_set_errorx(ctx, "connection context failure");
-			goto err;
-		}
-		*cctx = conn_ctx;
-
-		if ((conn_ctx->ssl_conn = SSL_new(ctx->ssl_ctx)) == NULL) {
-			tls_set_errorx(ctx, "ssl failure");
-			goto err;
-		}
-		if (SSL_set_app_data(conn_ctx->ssl_conn, conn_ctx) != 1) {
-			tls_set_errorx(ctx, "ssl application data failure");
-			goto err;
-		}
-		if (SSL_set_rfd(conn_ctx->ssl_conn, fd_read) != 1 ||
-		    SSL_set_wfd(conn_ctx->ssl_conn, fd_write) != 1) {
-			tls_set_errorx(ctx, "ssl file descriptor failure");
-			goto err;
-		}
+	if ((conn_ctx = tls_server_conn(ctx)) == NULL) {
+		tls_set_errorx(ctx, "connection context failure");
+		goto err;
 	}
 
-	if ((ret = SSL_accept(conn_ctx->ssl_conn)) != 1) {
-		err = tls_ssl_error(ctx, conn_ctx->ssl_conn, ret, "accept");
-		if (err == TLS_READ_AGAIN || err == TLS_WRITE_AGAIN) {
-			return (err);
-		}
+	if ((conn_ctx->ssl_conn = SSL_new(ctx->ssl_ctx)) == NULL) {
+		tls_set_errorx(ctx, "ssl failure");
+		goto err;
+	}
+	if (SSL_set_app_data(conn_ctx->ssl_conn, conn_ctx) != 1) {
+		tls_set_errorx(ctx, "ssl application data failure");
+		goto err;
+	}
+	if (SSL_set_rfd(conn_ctx->ssl_conn, fd_read) != 1 ||
+	    SSL_set_wfd(conn_ctx->ssl_conn, fd_write) != 1) {
+		tls_set_errorx(ctx, "ssl file descriptor failure");
 		goto err;
 	}
 
+	*cctx = conn_ctx;
+
 	return (0);
 
  err:
+	tls_free(conn_ctx);
+
+	*cctx = NULL;
+
 	return (-1);
 }
 
 int
-tls_accept_socket(struct tls *ctx, struct tls **cctx, int socket)
+tls_handshake_server(struct tls *ctx)
 {
-	return (tls_accept_fds(ctx, cctx, socket, socket));
+	int ssl_ret;
+	int rv = -1;
+
+	if ((ctx->flags & TLS_SERVER_CONN) == 0) {
+		tls_set_errorx(ctx, "not a server connection context");
+		goto err;
+	}
+
+	if ((ssl_ret = SSL_accept(ctx->ssl_conn)) != 1) {
+		rv = tls_ssl_error(ctx, ctx->ssl_conn, ssl_ret, "handshake");
+		goto err;
+	}
+
+	ctx->state |= TLS_HANDSHAKE_COMPLETE;
+
+ err:
+	return (rv);
 }