Ditch FEATURE_IMAGE_DETECT_MSIE

It's an obsolete workaround we inherited from Junkbuster
and was already disabled by default.

Users that feel the urge to work around issues with
image requests coming from an Internet Explorer version
from more than 15 years ago can still do this using tags.

diff --git a/acconfig.h b/acconfig.h
index 6d3639a..ab59de8 100644 (file)
--- a/acconfig.h
+++ b/acconfig.h
@@ -109,43 +109,9 @@
 /*
  * Allow blocking using images as well as HTML.
  * If you do not define this then everything is blocked as HTML.
- *
- * Note that this is required if you want to use FEATURE_IMAGE_DETECT_MSIE.
  */
 #undef FEATURE_IMAGE_BLOCKING
 
-/*
- * Detect image requests automatically for MSIE.  Will fall back to
- * other image-detection methods (i.e. "+image" permission) for other
- * browsers.
- *
- * You must also define FEATURE_IMAGE_BLOCKING to use this feature.
- *
- * It detects the following header pair as an image request:
- *
- * User-Agent: Mozilla/4.0 (compatible; MSIE 5.5; Windows NT 5.0)
- * Accept: * / *
- *
- * And the following as a HTML request:
- *
- * User-Agent: Mozilla/4.0 (compatible; MSIE 5.5; Windows NT 5.0)
- * Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, * / *
- *
- * And no, I haven't got that backwards - IE is being weird.
- *
- * Known limitations:
- * 1) If you press shift-reload on a blocked HTML page, you get
- *    the image "blocked" page, not the HTML "blocked" page.
- * 2) Once an image "blocked" page has been sent, viewing it
- *    in it's own browser window *should* bring up the HTML
- *    "blocked" page, but it doesn't.  You need to clear the
- *    browser cache to get the HTML version again.
- *
- * These limitations are due to IE making inconsistent choices
- * about which "Accept:" header to send.
- */
-#undef FEATURE_IMAGE_DETECT_MSIE
-
 /*
  * Use PNG instead of GIF for built-in images
  */

diff --git a/cgisimple.c b/cgisimple.c
index 078a001..74e5425 100644 (file)
--- a/cgisimple.c
+++ b/cgisimple.c
@@ -1,4 +1,4 @@
-const char cgisimple_rcs[] = "$Id: cgisimple.c,v 1.146 2017/02/20 13:45:14 fabiankeil Exp $";
+const char cgisimple_rcs[] = "$Id: cgisimple.c,v 1.147 2017/02/20 13:47:04 fabiankeil Exp $";
 /*********************************************************************
  *
  * File        :  $Source: /cvsroot/ijbswa/current/cgisimple.c,v $
@@ -1871,14 +1871,6 @@ static jb_err show_defines(struct map *exports)
          1,
 #else
          0,
-#endif
-      },
-      {
-         "FEATURE_IMAGE_DETECT_MSIE",
-#ifdef FEATURE_IMAGE_DETECT_MSIE
-         1,
-#else
-         0,
 #endif
       },
       {

diff --git a/configure.in b/configure.in
index 657edef..13f42a6 100644 (file)
--- a/configure.in
+++ b/configure.in
@@ -1,6 +1,6 @@
 dnl Process this file with autoconf to produce a configure script.
 dnl
-dnl $Id: configure.in,v 1.206 2016/09/27 22:48:28 ler762 Exp $
+dnl $Id: configure.in,v 1.207 2016/12/24 16:00:49 fabiankeil Exp $
 dnl
 dnl Written by and Copyright (C) 2001-2016 the
 dnl Privoxy team. https://www.privoxy.org/
@@ -32,7 +32,7 @@ dnl =================================================================
 dnl AutoConf Initialization
 dnl =================================================================
 
-AC_REVISION($Revision: 1.206 $)
+AC_REVISION($Revision: 1.207 $)
 AC_INIT(jcc.c)
 
 if test ! -f config.h.in; then
@@ -931,13 +931,6 @@ AC_ARG_ENABLE(stats,
   AC_DEFINE(FEATURE_STATISTICS)
 fi],AC_DEFINE(FEATURE_STATISTICS))
 
-AC_ARG_ENABLE(ie-images,
-[  --enable-ie-images              Enable a quick but not always reliable auto-detect whether requests from
-                                  MS Internet Explorer are for an image or not.],
-[if test $enableval = yes; then
-  AC_DEFINE(FEATURE_IMAGE_DETECT_MSIE)
-fi],)
-
 AC_ARG_ENABLE(image-blocking,
 [  --disable-image-blocking        Don't try to figure out whether a request is
                                   for an image or HTML - assume HTML.],

diff --git a/filters.c b/filters.c
index 0450f5a..49a9e89 100644 (file)
--- a/filters.c
+++ b/filters.c
@@ -1,4 +1,4 @@
-const char filters_rcs[] = "$Id: filters.c,v 1.202 2016/05/25 10:50:55 fabiankeil Exp $";
+const char filters_rcs[] = "$Id: filters.c,v 1.203 2016/12/24 16:00:49 fabiankeil Exp $";
 /*********************************************************************
  *
  * File        :  $Source: /cvsroot/ijbswa/current/filters.c,v $
@@ -1327,42 +1327,18 @@ struct http_response *redirect_url(struct client_state *csp)
  *
  * Function    :  is_imageurl
  *
- * Description :  Given a URL, decide whether it is an image or not,
- *                using either the info from a previous +image action
- *                or, #ifdef FEATURE_IMAGE_DETECT_MSIE, and the browser
- *                is MSIE and not on a Mac, tell from the browser's accept
- *                header.
+ * Description :  Given a URL, decide whether it should be treated
+ *                as image URL or not.
  *
  * Parameters  :
  *          1  :  csp = Current client state (buffers, headers, etc...)
  *
- * Returns     :  True (nonzero) if URL is an image, false (0)
+ * Returns     :  True (nonzero) if URL is an image URL, false (0)
  *                otherwise
  *
  *********************************************************************/
 int is_imageurl(const struct client_state *csp)
 {
-#ifdef FEATURE_IMAGE_DETECT_MSIE
-   char *tmp;
-
-   tmp = get_header_value(csp->headers, "User-Agent:");
-   if (tmp && strstr(tmp, "MSIE") && !strstr(tmp, "Mac_"))
-   {
-      tmp = get_header_value(csp->headers, "Accept:");
-      if (tmp && strstr(tmp, "image/gif"))
-      {
-         /* Client will accept HTML.  If this seems counterintuitive,
-          * blame Microsoft.
-          */
-         return(0);
-      }
-      else
-      {
-         return(1);
-      }
-   }
-#endif /* def FEATURE_IMAGE_DETECT_MSIE */
-
    return ((csp->action->flags & ACTION_IMAGE) != 0);
 
 }

diff --git a/templates/show-status b/templates/show-status
index b8c201c..d938b43 100644 (file)
--- a/templates/show-status
+++ b/templates/show-status
@@ -312,13 +312,6 @@
                IP addresses and in the configuration files.
               </td>
             </tr>
-            <tr>
-              <td><code>FEATURE_IMAGE_DETECT_MSIE</code></td>
-              <td>@if-FEATURE_IMAGE_DETECT_MSIE-then@ Yes @else-not-FEATURE_IMAGE_DETECT_MSIE@ No @endif-FEATURE_IMAGE_DETECT_MSIE@</td>
-              <td>Enables automatic detection of image and HTML requests from
-               Microsoft Internet Explorer users, overriding the setting of
-               +image in the actions file.</td>
-            </tr>
             <tr>
               <td><code>FEATURE_NO_GIFS</code></td>
               <td>@if-FEATURE_NO_GIFS-then@ Yes @else-not-FEATURE_NO_GIFS@ No @endif-FEATURE_NO_GIFS@</td>