commit 9ef31f01af6c59efe65fe0c4ab3be7316046ccca
author David Benjamin <davidben@google.com> Mon Oct 31 18:01:13 2016 -0400
committer Adam Langley <agl@google.com> Wed Nov 02 18:06:23 2016 +0000
tree e37f5287cae05050be98dcdcae9ccd1d68cf721d
parent b2e2e32c35a228d9e690c90fd5e1bb575dbb0984

Negotiate the cipher suite before ALPN.

HTTP/2 places requirements on the cipher suite. So that servers can
decline HTTP/2 when these requirements aren't met, defer ALPN
negotiation.

See also b/32553041.

Change-Id: Idbcf049f9c8bda06a8be52a0154fe76e84607268
Reviewed-on: https://boringssl-review.googlesource.com/11982
Reviewed-by: Adam Langley <agl@google.com>

ssl/handshake_server.c

diff --git a/ssl/handshake_server.c b/ssl/handshake_server.c
index 9200b85..d17e659 100644
--- a/ssl/handshake_server.c
+++ b/ssl/handshake_server.c
@@ -556,7 +556,7 @@
 }
 
 static int negotiate_version(
-    SSL *ssl, int *out_alert,
+    SSL *ssl, uint8_t *out_alert,
     const struct ssl_early_callback_ctx *client_hello) {
   uint16_t min_version, max_version;
   if (!ssl_get_version_range(ssl, &min_version, &max_version)) {
@@ -665,7 +665,8 @@
 }
 
 static int ssl3_get_client_hello(SSL *ssl) {
-  int al = SSL_AD_INTERNAL_ERROR, ret = -1;
+  uint8_t al = SSL_AD_INTERNAL_ERROR;
+  int ret = -1;
   SSL_SESSION *session = NULL;
 
   if (ssl->state == SSL3_ST_SR_CLNT_HELLO_A) {
@@ -887,6 +888,12 @@
     }
   }
 
+  /* Resolve ALPN after the cipher suite is selected. HTTP/2 negotiation depends
+   * on the cipher suite. */
+  if (!ssl_negotiate_alpn(ssl, &al, &client_hello)) {
+    goto f_err;
+  }
+
   /* Now that the cipher is known, initialize the handshake hash. */
   if (!ssl3_init_handshake_hash(ssl)) {
     goto f_err;