SSL: preserve default server context in connection (ticket #235).

This context is needed for shared sessions cache to work in configurations
with multiple virtual servers sharing the same port.  Unfortunately, OpenSSL
does not provide an API to access the session context, thus storing it
separately.

In collaboration with Vladimir Homutov.

src/event/ngx_event_openssl.c

diff --git a/src/event/ngx_event_openssl.c b/src/event/ngx_event_openssl.c
index 8550da9..57dfc6c 100644
--- a/src/event/ngx_event_openssl.c
+++ b/src/event/ngx_event_openssl.c
@@ -1038,6 +1038,8 @@
     sc->buffer = ((flags & NGX_SSL_BUFFER) != 0);
     sc->buffer_size = ssl->buffer_size;
 
+    sc->session_ctx = ssl->ctx;
+
     sc->connection = SSL_new(ssl->ctx);
 
     if (sc->connection == NULL) {
@@ -2305,7 +2307,7 @@
 
     c = ngx_ssl_get_connection(ssl_conn);
 
-    ssl_ctx = SSL_get_SSL_CTX(ssl_conn);
+    ssl_ctx = c->ssl->session_ctx;
     shm_zone = SSL_CTX_get_ex_data(ssl_ctx, ngx_ssl_session_cache_index);
 
     cache = shm_zone->data;
@@ -2443,21 +2445,17 @@
     ngx_ssl_sess_id_t        *sess_id;
     ngx_ssl_session_cache_t  *cache;
     u_char                    buf[NGX_SSL_MAX_SESSION_SIZE];
-#if (NGX_DEBUG)
     ngx_connection_t         *c;
-#endif
 
     hash = ngx_crc32_short(id, (size_t) len);
     *copy = 0;
 
-#if (NGX_DEBUG)
     c = ngx_ssl_get_connection(ssl_conn);
 
     ngx_log_debug2(NGX_LOG_DEBUG_EVENT, c->log, 0,
                    "ssl get session: %08XD:%d", hash, len);
-#endif
 
-    shm_zone = SSL_CTX_get_ex_data(SSL_get_SSL_CTX(ssl_conn),
+    shm_zone = SSL_CTX_get_ex_data(c->ssl->session_ctx,
                                    ngx_ssl_session_cache_index);
 
     cache = shm_zone->data;
@@ -2836,13 +2834,14 @@
     SSL_CTX                       *ssl_ctx;
     ngx_uint_t                     i;
     ngx_array_t                   *keys;
+    ngx_connection_t              *c;
     ngx_ssl_session_ticket_key_t  *key;
 #if (NGX_DEBUG)
     u_char                         buf[32];
-    ngx_connection_t              *c;
 #endif
 
-    ssl_ctx = SSL_get_SSL_CTX(ssl_conn);
+    c = ngx_ssl_get_connection(ssl_conn);
+    ssl_ctx = c->ssl->session_ctx;
 
     keys = SSL_CTX_get_ex_data(ssl_ctx, ngx_ssl_session_ticket_keys_index);
     if (keys == NULL) {
@@ -2851,10 +2850,6 @@
 
     key = keys->elts;
 
-#if (NGX_DEBUG)
-    c = ngx_ssl_get_connection(ssl_conn);
-#endif
-
     if (enc == 1) {
         /* encrypt session ticket */
 

src/event/ngx_event_openssl.h

diff --git a/src/event/ngx_event_openssl.h b/src/event/ngx_event_openssl.h
index 08eff64..c86be2a 100644
--- a/src/event/ngx_event_openssl.h
+++ b/src/event/ngx_event_openssl.h
@@ -46,6 +46,7 @@
 
 typedef struct {
     ngx_ssl_conn_t             *connection;
+    SSL_CTX                    *session_ctx;
 
     ngx_int_t                   last;
     ngx_buf_t                  *buf;