Automatically complete the handshake from tls13_legacy_{read,write}_bytes()

If the TLS handshake has not been completed, automatically complete the
handshake as part of the read/write call, implementing the current
SSL_read()/SSL_write() behaviour.

Once the TLS handshake is completed we push a WANT_POLLIN or WANT_POLLOUT
back up to the caller, since some applications appear to incorrectly call
SSL_read() or SSL_write(), rather than repeating the previous call. This
can lead to attempts to read data that does not exist, since the
WANT_POLLIN was actually triggered as part of the handshake.

ok inoguchi@ tb@

1 files changed, 13 insertions, 1 deletions

diff --git a/src/lib/libssl/tls13_lib.c b/src/lib/libssl/tls13_lib.c
index e371d71750..c5e2faf3fc 100644
--- a/src/lib/libssl/tls13_lib.c
+++ b/src/lib/libssl/tls13_lib.c
@@ -1,4 +1,4 @@
-/*      $OpenBSD: tls13_lib.c,v 1.7 2019/02/28 17:44:56 jsing Exp $ */
+/*      $OpenBSD: tls13_lib.c,v 1.8 2019/02/28 17:56:43 jsing Exp $ */
 /*
  * Copyright (c) 2018, 2019 Joel Sing <jsing@openbsd.org>
  *
@@ -241,6 +241,12 @@ tls13_legacy_read_bytes(SSL *ssl, int type, unsigned char *buf, int len, int pee
         struct tls13_ctx *ctx = ssl->internal->tls13;
         ssize_t ret;
 
+        if (ctx == NULL || !ctx->handshake_completed) {
+                if ((ret = ssl->internal->handshake_func(ssl)) <= 0)
+                        return ret;
+                return tls13_legacy_return_code(ssl, TLS13_IO_WANT_POLLIN);
+        }
+
         if (peek) {
                 /* XXX - support peek... */
                 SSLerror(ssl, ERR_R_INTERNAL_ERROR);
@@ -266,6 +272,12 @@ tls13_legacy_write_bytes(SSL *ssl, int type, const void *buf, int len)
         struct tls13_ctx *ctx = ssl->internal->tls13;
         ssize_t ret;
 
+        if (ctx == NULL || !ctx->handshake_completed) {
+                if ((ret = ssl->internal->handshake_func(ssl)) <= 0)
+                        return ret;
+                return tls13_legacy_return_code(ssl, TLS13_IO_WANT_POLLOUT);
+        }
+
         if (type != SSL3_RT_APPLICATION_DATA) {
                 SSLerror(ssl, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
                 return -1;