From 2be4aa71648e1f72530c53e2dc6f4ecb7bcfca2c Mon Sep 17 00:00:00 2001
From: David Benjamin <davidben@google.com>
Date: Mon, 2 Jan 2017 07:56:51 -0500
Subject: [PATCH] Add a helper function for resetting SSL_get_error state.

We repeat this in a bunch of places.

Change-Id: Iee2c95a13e1645453f101d8be4be9ac78d520387
Reviewed-on: https://boringssl-review.googlesource.com/13051
Reviewed-by: David Benjamin <davidben@google.com>
---
 ssl/d1_lib.c   |  4 +---
 ssl/internal.h |  3 +++
 ssl/ssl_lib.c  | 24 ++++++++++--------------
 3 files changed, 14 insertions(+), 17 deletions(-)

diff --git a/ssl/d1_lib.c b/ssl/d1_lib.c
index ba3c844b9..258e9ab29 100644
--- a/ssl/d1_lib.c
+++ b/ssl/d1_lib.c
@@ -236,9 +236,7 @@ int dtls1_check_timeout_num(SSL *ssl) {
 }
 
 int DTLSv1_handle_timeout(SSL *ssl) {
-  ssl->rwstate = SSL_NOTHING;
-  /* Functions which use SSL_get_error must clear the error queue on entry. */
-  ERR_clear_error();
+  ssl_reset_error_state(ssl);
 
   if (!SSL_is_dtls(ssl)) {
     return -1;
diff --git a/ssl/internal.h b/ssl/internal.h
index 97ae6a012..e26fa13ef 100644
--- a/ssl/internal.h
+++ b/ssl/internal.h
@@ -1946,6 +1946,9 @@ void ssl_set_client_disabled(SSL *ssl);
 
 void ssl_get_current_time(const SSL *ssl, struct timeval *out_clock);
 
+/* ssl_reset_error_state resets state for |SSL_get_error|. */
+void ssl_reset_error_state(SSL *ssl);
+
 
 #if defined(__cplusplus)
 } /* extern C */
diff --git a/ssl/ssl_lib.c b/ssl/ssl_lib.c
index 806bdba8d..2e9f4a6e2 100644
--- a/ssl/ssl_lib.c
+++ b/ssl/ssl_lib.c
@@ -612,11 +612,16 @@ BIO *SSL_get_wbio(const SSL *ssl) {
   return ssl->wbio;
 }
 
-int SSL_do_handshake(SSL *ssl) {
+void ssl_reset_error_state(SSL *ssl) {
+  /* Functions which use |SSL_get_error| must reset I/O and error state on
+   * entry. */
   ssl->rwstate = SSL_NOTHING;
-  /* Functions which use SSL_get_error must clear the error queue on entry. */
   ERR_clear_error();
   ERR_clear_system_error();
+}
+
+int SSL_do_handshake(SSL *ssl) {
+  ssl_reset_error_state(ssl);
 
   if (ssl->handshake_func == NULL) {
     OPENSSL_PUT_ERROR(SSL, SSL_R_CONNECTION_TYPE_NOT_SET);
@@ -735,10 +740,7 @@ static int ssl_do_post_handshake(SSL *ssl) {
 }
 
 static int ssl_read_impl(SSL *ssl, void *buf, int num, int peek) {
-  ssl->rwstate = SSL_NOTHING;
-  /* Functions which use SSL_get_error must clear the error queue on entry. */
-  ERR_clear_error();
-  ERR_clear_system_error();
+  ssl_reset_error_state(ssl);
 
   if (ssl->handshake_func == NULL) {
     OPENSSL_PUT_ERROR(SSL, SSL_R_UNINITIALIZED);
@@ -784,10 +786,7 @@ int SSL_peek(SSL *ssl, void *buf, int num) {
 }
 
 int SSL_write(SSL *ssl, const void *buf, int num) {
-  ssl->rwstate = SSL_NOTHING;
-  /* Functions which use SSL_get_error must clear the error queue on entry. */
-  ERR_clear_error();
-  ERR_clear_system_error();
+  ssl_reset_error_state(ssl);
 
   if (ssl->handshake_func == NULL) {
     OPENSSL_PUT_ERROR(SSL, SSL_R_UNINITIALIZED);
@@ -815,10 +814,7 @@ int SSL_write(SSL *ssl, const void *buf, int num) {
 }
 
 int SSL_shutdown(SSL *ssl) {
-  ssl->rwstate = SSL_NOTHING;
-  /* Functions which use SSL_get_error must clear the error queue on entry. */
-  ERR_clear_error();
-  ERR_clear_system_error();
+  ssl_reset_error_state(ssl);
 
   if (ssl->handshake_func == NULL) {
     OPENSSL_PUT_ERROR(SSL, SSL_R_UNINITIALIZED);