[PATCH] make mod_proxy not accept HTTP/0.9

[Adam Sussman]

This patch adds a configuration directive "ProxyRequireValidHTTPStatus".
When enabled, mod_proxy will require a valid HTTP status line from the
destination server and throw a 502 Bad Gateway error if it does not
get it.  Basicaly, this disallows backasswards reponses.

Why would one want to do this?  Well, I have a setup where my handler
is first attempting one proxy destination, and if that does not work,
it tries another.  It works by discarding the output of any response
that isn't a 200 and then trying another gateway.

If the gateway doesn't return a valid HTTP 1.0 or better status line,
mod_proxy assumes a 200 OK response.  In my environment, I control all
the gateway servers so I know that a working gateway will always give
me a real HTTP status line.  If it doesn't, I want to consider it a
bad gateway and try another.

-adam


Index: mod_proxy.c
===================================================================
RCS file: /home/cvspublic/httpd-2.0/modules/proxy/mod_proxy.c,v
retrieving revision 1.76
diff -u -r1.76 mod_proxy.c
--- mod_proxy.c 21 Mar 2002 12:05:45 -0000      1.76
+++ mod_proxy.c 30 Mar 2002 01:40:52 -0000
@@ -502,6 +502,7 @@
     ps->preserve_host =0;    
     ps->timeout=0;
     ps->timeout_set=0;
+    ps->require_valid_http_status=0;
     return ps;
 }
 
@@ -833,6 +834,16 @@
 }
 
 static const char *
+    set_require_valid_http_status(cmd_parms *parms, void *dummy, int flag)
+{
+    proxy_server_conf *psf =
+    ap_get_module_config(parms->server->module_config, &proxy_module);
+
+    psf->require_valid_http_status = flag;
+    return NULL;
+}
+
+static const char *
     set_recv_buffer_size(cmd_parms *parms, void *dummy, const char *arg)
 {
     proxy_server_conf *psf =
@@ -1041,6 +1052,8 @@
     AP_INIT_TAKE1("ProxyTimeout", set_proxy_timeout, NULL, RSRC_CONF,
      "Set the timeout (in seconds) for a proxied connection. "
      "This overrides the server timeout"),
+    AP_INIT_FLAG("ProxyRequireValidHTTPStatus", set_require_valid_http_status, NULL, 
+RSRC_CONF,
+     "on if proxy should not accept reponses that don't give a valid HTTP 1.0 (or 
+better) status line"),
  
     {NULL}
 };
Index: mod_proxy.h
===================================================================
RCS file: /home/cvspublic/httpd-2.0/modules/proxy/mod_proxy.h,v
retrieving revision 1.76
diff -u -r1.76 mod_proxy.h
--- mod_proxy.h 13 Mar 2002 20:47:53 -0000      1.76
+++ mod_proxy.h 30 Mar 2002 01:40:52 -0000
@@ -196,6 +196,8 @@
     int timeout;
     int timeout_set;
 
+    int require_valid_http_status;
+
 } proxy_server_conf;
 
 typedef struct {
Index: proxy_http.c
===================================================================
RCS file: /home/cvspublic/httpd-2.0/modules/proxy/proxy_http.c,v
retrieving revision 1.138
diff -u -r1.138 proxy_http.c
--- proxy_http.c        21 Mar 2002 12:05:45 -0000      1.138
+++ proxy_http.c        30 Mar 2002 01:40:52 -0000
@@ -730,6 +730,12 @@
                 p_conn->close += 1;
                 origin->keepalive = 0;
             }
+        } else if (conf->require_valid_http_status) {
+            apr_socket_close(p_conn->sock);
+            backend->connection = NULL;
+            return ap_proxyerror(r, HTTP_BAD_GATEWAY,
+                        apr_pstrcat(p, "Corrupt status line returned by remote "
+                                    "server: ", buffer, NULL));
         } else {
             /* an http/0.9 response */
             backasswards = 1;