apache2/apache2-mod_ssl_npn.patch

# This patch adds hooks for Next Protocol Negotiation (NPN) into mod_ssl.  This
# change is under review to be included in Apache trunk:
#   https://issues.apache.org/bugzilla/show_bug.cgi?id=52210
# But until it becomes part of an Apache 2.2 release, we need to apply the patch
# ourselves.
Index: modules/ssl/ssl_private.h
===================================================================
--- modules/ssl/ssl_private.h	(revision 1202283)
+++ modules/ssl/ssl_private.h	(working copy)
@@ -603,6 +603,7 @@
 #ifndef OPENSSL_NO_TLSEXT
 int          ssl_callback_ServerNameIndication(SSL *, int *, modssl_ctx_t *);
 #endif
+int ssl_callback_AdvertiseNextProtos(SSL *ssl, const unsigned char **data, unsigned int *len, void *arg);
 
 /**  Session Cache Support  */
 void         ssl_scache_init(server_rec *, apr_pool_t *);
@@ -714,4 +715,3 @@
 
 #endif /* SSL_PRIVATE_H */
 /** @} */
-
Index: modules/ssl/ssl_engine_init.c
===================================================================
--- modules/ssl/ssl_engine_init.c	(revision 1202283)
+++ modules/ssl/ssl_engine_init.c	(working copy)
@@ -559,6 +559,11 @@
     SSL_CTX_set_tmp_dh_callback(ctx,  ssl_callback_TmpDH);
 
     SSL_CTX_set_info_callback(ctx, ssl_callback_Info);
+
+#if OPENSSL_VERSION_NUMBER >= 0x10001000L && !defined(OPENSSL_NO_TLSEXT) && !defined(OPENSSL_NO_NEXTPROTONEG)
+    SSL_CTX_set_next_protos_advertised_cb(
+        ctx, ssl_callback_AdvertiseNextProtos, NULL);
+#endif
 }
 
 static void ssl_init_ctx_verify(server_rec *s,
@@ -1352,4 +1357,3 @@
 
     return APR_SUCCESS;
 }
-
Index: modules/ssl/ssl_engine_io.c
===================================================================
--- modules/ssl/ssl_engine_io.c	(revision 1202283)
+++ modules/ssl/ssl_engine_io.c	(working copy)
@@ -338,6 +338,7 @@
     apr_pool_t *pool;
     char buffer[AP_IOBUFSIZE];
     ssl_filter_ctx_t *filter_ctx;
+    int npn_finished;  /* 1 if NPN has finished, 0 otherwise */
 } bio_filter_in_ctx_t;
 
 /*
@@ -1409,6 +1410,21 @@
         APR_BRIGADE_INSERT_TAIL(bb, bucket);
     }
 
+    /* By this point, Next Protocol Negotiation (NPN) should be completed (if
+     * our version of OpenSSL supports it).  If we haven't already, find out
+     * which protocol was decided upon and inform other modules by calling
+     * npn_proto_negotiated_hook. */
+    if (!inctx->npn_finished) {
+        inctx->npn_finished = 1;
+#if OPENSSL_VERSION_NUMBER >= 0x10001000L && !defined(OPENSSL_NO_TLSEXT) && !defined(OPENSSL_NO_NEXTPROTONEG)
+        const unsigned char *next_proto = NULL;
+        unsigned next_proto_len = 0;
+        SSL_get0_next_proto_negotiated(inctx->ssl, &next_proto,
+                                       &next_proto_len);
+        ssl_run_npn_proto_negotiated_hook(f->c, next_proto, next_proto_len);
+#endif
+    }
+
     return APR_SUCCESS;
 }
 
@@ -1753,6 +1769,7 @@
     inctx->block = APR_BLOCK_READ;
     inctx->pool = c->pool;
     inctx->filter_ctx = filter_ctx;
+    inctx->npn_finished = 0;
 }
 
 void ssl_io_filter_init(conn_rec *c, SSL *ssl)
Index: modules/ssl/ssl_engine_kernel.c
===================================================================
--- modules/ssl/ssl_engine_kernel.c	(revision 1202283)
+++ modules/ssl/ssl_engine_kernel.c	(working copy)
@@ -1969,6 +1969,77 @@
     }
 }
 
+/*
+ * This callback function is executed when SSL needs to decide what protocols
+ * to advertise during Next Protocol Negotiation (NPN).  It must produce a
+ * string in wire format -- a sequence of length-prefixed strings -- indicating
+ * the advertised protocols.  Refer to SSL_CTX_set_next_protos_advertised_cb
+ * in OpenSSL for reference.
+ */
+int ssl_callback_AdvertiseNextProtos(SSL *ssl, const unsigned char **data_out,
+                                     unsigned int *size_out, void *arg)
+{
+    *data_out = NULL;
+    *size_out = 0;
+
+    /* Get the connection object.  If it's not available, then there's nothing
+     * for us to do. */
+    conn_rec *c = (conn_rec*)SSL_get_app_data(ssl);
+    if (c == NULL) {
+        return SSL_TLSEXT_ERR_OK;
+    }
+
+    /* Invoke our npn_advertise_protos hook, giving other modules a chance to
+     * add alternate protocol names to advertise. */
+    apr_array_header_t *protos = apr_array_make(c->pool, 0, sizeof(char*));
+    ssl_run_npn_advertise_protos_hook(c, protos);
+    int num_protos = protos->nelts;
+
+    /* If no other modules added any alternate protocols, then we're done. */
+    if (num_protos == 0) {
+        return SSL_TLSEXT_ERR_OK;
+    }
+
+    /* We now have a list of null-terminated strings; we need to concatenate
+     * them together into a single string, where each protocol name is prefixed
+     * by its length.  First, calculate how long that string will be. */
+    unsigned int size = 0;
+    int i;
+    for (i = 0; i < num_protos; ++i) {
+        const char* string = APR_ARRAY_IDX(protos, i, const char*);
+        unsigned int length = strlen(string);
+        /* If the protocol name is too long (the length must fit in one byte),
+         * then log an error and quit. */
+        if (length > 255) {
+            ap_log_cerror(APLOG_MARK, APLOG_ERR, 0, c,
+                          "SSL NPN protocol name too long (length=%u): %s",
+                          length, string);
+            return SSL_TLSEXT_ERR_OK;
+        }
+        /* Leave room for the length prefix (one byte) plus the protocol name
+         * itself. */
+        size += 1 + length;
+    }
+
+    /* Now we can build the string.  Copy each protocol name string into the
+     * larger string, prefixed by its length. */
+    unsigned char* data = apr_palloc(c->pool, size * sizeof(unsigned char));
+    unsigned char* start = data;
+    for (i = 0; i < num_protos; ++i) {
+        const char* string = APR_ARRAY_IDX(protos, i, const char*);
+        size_t length = strlen(string);
+        *start = (unsigned char)length;
+        ++start;
+        memcpy(start, string, length * sizeof(unsigned char));
+        start += length;
+    }
+
+    /* Success. */
+    *data_out = data;
+    *size_out = size;
+    return SSL_TLSEXT_ERR_OK;
+}
+
 #ifndef OPENSSL_NO_TLSEXT
 /*
  * This callback function is executed when OpenSSL encounters an extended
Index: modules/ssl/mod_ssl.c
===================================================================
--- modules/ssl/mod_ssl.c	(revision 1202283)
+++ modules/ssl/mod_ssl.c	(working copy)
@@ -220,6 +220,18 @@
     AP_END_CMD
 };
 
+/* Implement 'ssl_run_npn_advertise_protos_hook'. */
+APR_IMPLEMENT_OPTIONAL_HOOK_RUN_ALL(
+    ssl, AP, int, npn_advertise_protos_hook,
+    (conn_rec* connection, apr_array_header_t* protos),
+    (connection, protos), OK, DECLINED);
+
+/* Implement 'ssl_run_npn_proto_negotiated_hook'. */
+APR_IMPLEMENT_OPTIONAL_HOOK_RUN_ALL(
+    ssl, AP, int, npn_proto_negotiated_hook,
+    (conn_rec* connection, char* proto_name, apr_size_t proto_name_len),
+    (connection, proto_name, proto_name_len), OK, DECLINED);
+
 /*
  *  the various processing hooks
  */
Index: modules/ssl/mod_ssl.h
===================================================================
--- modules/ssl/mod_ssl.h	(revision 1202283)
+++ modules/ssl/mod_ssl.h	(working copy)
@@ -60,5 +60,26 @@
 
 APR_DECLARE_OPTIONAL_FN(apr_array_header_t *, ssl_extlist_by_oid, (request_rec *r, const char *oidstr));
 
+/** The npn_advertise_protos optional hook allows other modules to add entries
+ * to the list of protocol names advertised by the server during the Next
+ * Protocol Negotiation (NPN) portion of the SSL handshake.  The hook callee is
+ * given the connection and an APR array; it should push one or more char*'s
+ * pointing to null-terminated strings (such as "http/1.1" or "spdy/2") onto
+ * the array and return OK, or do nothing and return DECLINED. */
+APR_DECLARE_EXTERNAL_HOOK(ssl, AP, int, npn_advertise_protos_hook,
+                          (conn_rec* connection, apr_array_header_t* protos));
+
+/** The npn_proto_negotiated optional hook allows other modules to discover the
+ * name of the protocol that was chosen during the Next Protocol Negotiation
+ * (NPN) portion of the SSL handshake.  Note that this may be the empty string
+ * (in which case modules should probably assume HTTP), or it may be a protocol
+ * that was never even advertised by the server.  The hook callee is given the
+ * connection, a non-null-terminated string containing the protocol name, and
+ * the length of the string; it should do something appropriate (i.e. insert or
+ * remove filters) and return OK, or do nothing and return DECLINED. */
+APR_DECLARE_EXTERNAL_HOOK(ssl, AP, int, npn_proto_negotiated_hook,
+                          (conn_rec* connection, char* proto_name,
+                           apr_size_t proto_name_len));
+
 #endif /* __MOD_SSL_H__ */
 /** @} */