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Posted to modproxy-dev@apache.org by Ghislaine Labouret <Gh...@hsc.fr> on 2001/11/30 16:25:14 UTC

Re: mod_proxy/8724: Multiple occurences of response headers get removed by mod_proxy

On 9 Nov 2001 16:57:28 -0000, Ghislaine Labouret wrote:

> >Number:         8724
> >Category:       mod_proxy
> >Synopsis:       Multiple occurences of response headers get removed by mod_proxy
> >Confidential:   no
> >Severity:       non-critical
> >Priority:       medium
> >Responsible:    apache
> >State:          open
> >Quarter:        
> >Keywords:       
> >Date-Required:
> >Class:          sw-bug
> >Submitter-Id:   unknown
> >Arrival-Date:   Fri Nov 09 09:00:00 PST 2001
> >Closed-Date:
> >Last-Modified:
> >Originator:     Ghislaine.Labouret@hsc.fr
> >Release:        1.3.22
> >Organization:
> apache
> >Environment:
> Tested on Solaris 2.6
> >Description:
> When the answer from a web server to mod_proxy includes, for exemple, several
> "Expires:" headers (I know, this is unusual...), only the first one is 
> transmitted to the client by mod_proxy.
> 
> The cause is in proxy_http.c, line 511&512:
>     if ((datestr = ap_table_get(resp_hdrs, "Expires")) != NULL)
>         ap_table_set(resp_hdrs, "Expires", ap_proxy_date_canon(p, datestr));
> 
> In the above code, ap_table_get only gets the first occurence of the header,
> and ap_table_set removes all other occurences.
> 
> The same problem occurs for other response headers that are modified by 
> mod_proxy.
> >How-To-Repeat:
> 
> >Fix:

The following patch solves the issue. Would the mod_proxy team consider 
including it or somtehing to the same effect?


--- proxy_http.c-orig	Mon Nov 26 19:01:35 2001
+++ proxy_http.c	Fri Nov 30 18:09:39 2001
@@ -158,6 +158,29 @@
     ap_table_unset(headers, "Connection");
 }
 
+struct proxy_date_canon_parms {
+    pool *pool;
+    table *table;
+};
+
+static int proxy_date_canon(void *rec, const char *key, const char *value)
+{
+    pool *p; 
+    table *new_resp_hdrs;
+
+    p = ((struct proxy_date_canon_parms *) rec)->pool;
+    new_resp_hdrs = ((struct proxy_date_canon_parms *) rec)->table;
+
+    if (   (strcasecmp(key, "Date") == 0)
+	|| (strcasecmp(key, "Last-Modified") == 0)
+	|| (strcasecmp(key, "Expires") == 0))
+	ap_table_add(new_resp_hdrs, key, ap_proxy_date_canon(p, value));
+    else
+	ap_table_add(new_resp_hdrs, key, value);
+
+    return 1;
+}
+
 /*
  * This handles http:// URLs, and other URLs using a remote proxy over http
  * If proxyhost is NULL, then contact the server directly, otherwise
@@ -188,6 +211,7 @@
     int destport = 0;
     char *destportstr = NULL;
     const char *urlptr = NULL;
+    struct proxy_date_canon_parms do_par;
     const char *datestr;
     struct tbl_do_args tdo;
 #ifdef EAPI
@@ -504,12 +528,12 @@
  * HTTP/1.0 requires us to accept 3 types of dates, but only generate
  * one type
  */
-    if ((datestr = ap_table_get(resp_hdrs, "Date")) != NULL)
-	ap_table_set(resp_hdrs, "Date", ap_proxy_date_canon(p, datestr));
-    if ((datestr = ap_table_get(resp_hdrs, "Last-Modified")) != NULL)
-	ap_table_set(resp_hdrs, "Last-Modified", ap_proxy_date_canon(p, datestr));
-    if ((datestr = ap_table_get(resp_hdrs, "Expires")) != NULL)
-	ap_table_set(resp_hdrs, "Expires", ap_proxy_date_canon(p, datestr));
+    do_par.pool = p;
+    do_par.table = ap_make_table(p, 20);
+    ap_table_do((int (*)(void *, const char *, const char *))proxy_date_canon,
+                (void *) &do_par, resp_hdrs, NULL);
+    ap_clear_table(resp_hdrs);
+    resp_hdrs = do_par.table;
 
     if ((datestr = ap_table_get(resp_hdrs, "Location")) != NULL)
 	ap_table_set(resp_hdrs, "Location", proxy_location_reverse_map(r, datestr));


--
Ghislaine Labouret, Network security consultant
Hervé Schauer Consultants (HSC) - http://www.hsc.fr/
Phone (+33)-141-409-700 - Fax (+33)-141-409-709

Re: mod_proxy/8724: Multiple occurences of response headers get removed by mod_proxy

Posted by Graham Leggett <mi...@sharp.fm>.
Ghislaine Labouret wrote:

> > In the above code, ap_table_get only gets the first occurence of the header,
> > and ap_table_set removes all other occurences.
> >
> > The same problem occurs for other response headers that are modified by
> > mod_proxy.
> > >How-To-Repeat:
> >
> > >Fix:
> 
> The following patch solves the issue. Would the mod_proxy team consider
> including it or somtehing to the same effect?

What does RFC2616 (etc) say about duplicated Date, Expires and
Last-Modified headers?

I can't see an application for having more than one of these headers in
a request - is the current proxy behavior (reducing many occurences to
one occurence) not the correct behavior?

Regards,
Graham
-- 
-----------------------------------------
minfrin@sharp.fm		"There's a moon
					over Bourbon Street
						tonight..."

Re: mod_proxy/8724: Multiple occurences of response headers get removed by mod_proxy

Posted by Graham Leggett <mi...@sharp.fm>.
Ghislaine Labouret wrote:

> > In the above code, ap_table_get only gets the first occurence of the header,
> > and ap_table_set removes all other occurences.
> >
> > The same problem occurs for other response headers that are modified by
> > mod_proxy.
> > >How-To-Repeat:
> >
> > >Fix:
> 
> The following patch solves the issue. Would the mod_proxy team consider
> including it or somtehing to the same effect?

What does RFC2616 (etc) say about duplicated Date, Expires and
Last-Modified headers?

I can't see an application for having more than one of these headers in
a request - is the current proxy behavior (reducing many occurences to
one occurence) not the correct behavior?

Regards,
Graham
-- 
-----------------------------------------
minfrin@sharp.fm		"There's a moon
					over Bourbon Street
						tonight..."