[PATCH 09 of 31] Better handle various per-server ssl options with SNI

[Maxim Dounin]

# HG changeset patch
# User Maxim Dounin <mdounin at mdounin.ru>
# Date 1297776673 -10800
# Node ID b9e6b52e3baebb078a15f7e72566de8413a550af
# Parent  df54b6fc5e3f93f1132de6e686f4da53ce067696
Better handle various per-server ssl options with SNI.

SSL_set_SSL_CTX() doesn't touch values cached within ssl connection
structure, it only changes certificates (at least as of now, OpenSSL
1.0.0a and earlier).

As a result settings like ssl_verify_client, ssl_verify_depth,
ssl_prefer_server_ciphers are only configurable on per-socket basis while
with SNI it should be possible to specify them different for two servers
listening on the same socket.

Workaround is to explicitly re-apply settings we care about from context
to ssl connection in servername callback.

Note that SSL_clear_options() is only available in OpenSSL 0.9.8m+.  I.e.
with older versions it is not possible to clear ssl_prefer_server_ciphers
option if it's set in default server for a socket.

diff --git a/src/http/ngx_http_request.c b/src/http/ngx_http_request.c
--- a/src/http/ngx_http_request.c
+++ b/src/http/ngx_http_request.c
@@ -673,6 +673,24 @@ ngx_http_ssl_servername(ngx_ssl_conn_t *
 
     SSL_set_SSL_CTX(ssl_conn, sscf->ssl.ctx);
 
+    /*
+     * SSL_set_SSL_CTX() only changes certs as of 1.0.0a
+     * adjust other things we care about
+     */
+
+    SSL_set_verify(ssl_conn, SSL_CTX_get_verify_mode(sscf->ssl.ctx),
+                   SSL_CTX_get_verify_callback(sscf->ssl.ctx));
+
+    SSL_set_verify_depth(ssl_conn, SSL_CTX_get_verify_depth(sscf->ssl.ctx));
+
+#ifdef SSL_CTRL_CLEAR_OPTIONS
+    /* only in 0.9.8m+ */
+    SSL_clear_options(ssl_conn, SSL_get_options(ssl_conn) &
+                                ~SSL_CTX_get_options(sscf->ssl.ctx));
+#endif
+
+    SSL_set_options(ssl_conn, SSL_CTX_get_options(sscf->ssl.ctx));
+
     return SSL_TLSEXT_ERR_OK;
 }