From: Joe Orton <jorton@apache.org>
Date: Mon, 2 Jul 2012 08:51:01 +0000 (+0000)
Subject: * modules/mappers/mod_rewrite.c (cmd_rewriteoptions, hook_uri2file):
X-Git-Tag: 2.5.0-alpha~6683
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=83acd755ee086266e9fa1c85bddadf6b14ad5c1e;p=thirdparty%2Fapache%2Fhttpd.git

* modules/mappers/mod_rewrite.c (cmd_rewriteoptions, hook_uri2file):
  Add "AllowAnyURI" flag which disables the strict URL-path input
  string check introduced to fix CVE-2011-3368/CVE-2011-4317.

* docs/manual: Update docs.

Inspired by: covener


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1356115 13f79535-47bb-0310-9956-ffa450edef68
---

diff --git a/CHANGES b/CHANGES
index 706120633f8..e153e7eb647 100644
--- a/CHANGES
+++ b/CHANGES
@@ -6,6 +6,8 @@ Changes with Apache 2.5.0
      possible XSS for a site where untrusted users can upload files to
      a location with MultiViews enabled. [Niels Heinen <heinenn google.com>]
 
+  *) mod_rewrite: Add "AllowAnyURI" option. PR 52774. [Joe Orton]
+
   *) mod_ssl: Add RFC 5878 support. [Ben Laurie]
 
   *) mod_authz_core: If an expression in "Require expr" returns denied and
diff --git a/docs/manual/mod/mod_rewrite.xml b/docs/manual/mod/mod_rewrite.xml
index 7ba1eddd3f5..ae2b9acc6a1 100644
--- a/docs/manual/mod/mod_rewrite.xml
+++ b/docs/manual/mod/mod_rewrite.xml
@@ -188,6 +188,38 @@ later</compatibility>
       later.</p>
       </dd>
 
+      <dt><code>AllowAnyURI</code></dt>
+      <dd>
+
+      <p>When <directive module="mod_rewrite">RewriteRule</directive>
+      is used in <code>VirtualHost</code> or server context with
+      version 2.2.22 or later of httpd, <module>mod_rewrite</module>
+      will only process the rewrite rules if the request URI is a <a
+      href="./directive-dict.html#Syntax">URL-path</a>.  This avoids
+      some security issues where particular rules could allow
+      "surprising" pattern expansions (see <a
+      href="http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2011-3368">CVE-2011-3368</a>
+      and <a
+      href="http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2011-4317">CVE-2011-4317</a>).
+      To lift the restriction on matching a URL-path, the
+      <code>AllowAnyURI</code> option can be enabled, and
+      <module>mod_rewrite</module> will apply the rule set to any
+      request URI string, regardless of whether that string matches
+      the URL-path grammar required by the HTTP specification.</p>
+
+      <note type="warning">
+      <title>Security Warning</title> 
+
+      <p>Enabling this option will make the server vulnerable to
+      security issues if used with rewrite rules which are not
+      carefully authored.  It is <strong>strongly recommended</strong>
+      that this option is not used.  In particular, beware of input
+      strings containing the '<code>@</code>' character which could
+      change the interpretation of the transformed URI, as per the
+      above CVE names.</p>
+      </note>
+      </dd>
+
       </dl>
 
 </usage>
diff --git a/modules/mappers/mod_rewrite.c b/modules/mappers/mod_rewrite.c
index 314b48a1e51..7024eae7d4e 100644
--- a/modules/mappers/mod_rewrite.c
+++ b/modules/mappers/mod_rewrite.c
@@ -190,6 +190,7 @@ static const char* really_last_key = "rewrite_really_last";
 #define OPTION_INHERIT              1<<1
 #define OPTION_INHERIT_BEFORE       1<<2
 #define OPTION_NOSLASH              1<<3
+#define OPTION_ANYURI               1<<4
 
 #ifndef RAND_MAX
 #define RAND_MAX 32767
@@ -2895,6 +2896,9 @@ static const char *cmd_rewriteoptions(cmd_parms *cmd,
                          "LimitInternalRecursion directive and will be "
                          "ignored.");
         }
+        else if (!strcasecmp(w, "allowanyuri")) {
+            options |= OPTION_ANYURI;
+        }
         else {
             return apr_pstrcat(cmd->pool, "RewriteOptions: unknown option '",
                                w, "'", NULL);
@@ -4443,8 +4447,14 @@ static int hook_uri2file(request_rec *r)
         return DECLINED;
     }
 
-    if ((r->unparsed_uri[0] == '*' && r->unparsed_uri[1] == '\0')
-        || !r->uri || r->uri[0] != '/') {
+    /* Unless the anyuri option is set, ensure that the input to the
+     * first rule really is a URL-path, avoiding security issues with
+     * poorly configured rules.  See CVE-2011-3368, CVE-2011-4317. */
+    if ((dconf->options & OPTION_ANYURI) == 0
+        && ((r->unparsed_uri[0] == '*' && r->unparsed_uri[1] == '\0')
+            || !r->uri || r->uri[0] != '/')) {
+        rewritelog((r, 8, NULL, "Declining, request-URI '%s' is not a URL-path",
+                    r->uri));
         return DECLINED;
     }