From 1b461200ccbad9368846c140013ee3370df14749 Mon Sep 17 00:00:00 2001
From: Eric Covener <covener@apache.org>
Date: Thu, 29 Dec 2016 18:39:24 +0000
Subject: [PATCH] PR60009: RewriteRule local prefix checking update

  *) mod_rewrite: When a substitution is a fully qualified URL, and the
     scheme/host/port matches the current virtual host, stop interpreting the
     path component as a local path just because the first component of the
     path exists in the filesystem.  Adds RewriteOption "LegacyPrefixDocRoot"
     to revert to previous behavior. PR60009.

Submitted By: Hank Ibell <hwibell gmail.com>




git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1776463 13f79535-47bb-0310-9956-ffa450edef68
---
 CHANGES                         |  7 +++++++
 docs/manual/mod/mod_rewrite.xml | 19 +++++++++++++++++++
 modules/mappers/mod_rewrite.c   | 19 ++++++++++++++++++-
 3 files changed, 44 insertions(+), 1 deletion(-)

diff --git a/CHANGES b/CHANGES
index a5f089c6e9..f6025e404e 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,5 +1,12 @@
                                                          -*- coding: utf-8 -*-
 Changes with Apache 2.5.0
+
+  *) mod_rewrite: When a substitution is a fully qualified URL, and the 
+     scheme/host/port matches the current virtual host, stop interpreting the 
+     path component as a local path just because the first component of the 
+     path exists in the filesystem.  Adds RewriteOption "LegacyPrefixDocRoot" 
+     to revert to previous behavior. PR60009.
+     [Hank Ibell <hwibell gmail.com>]
  
   *) core: Add %{REMOTE_PORT} to the expression parser. PR59938
      [Hank Ibell <hwibell gmail.com>]
diff --git a/docs/manual/mod/mod_rewrite.xml b/docs/manual/mod/mod_rewrite.xml
index 039d5bec5d..e6e53daf59 100644
--- a/docs/manual/mod/mod_rewrite.xml
+++ b/docs/manual/mod/mod_rewrite.xml
@@ -272,6 +272,25 @@ LogLevel alert rewrite:trace3
          supply this extended context info.  Available in 2.4.16 and later.</p>
       </dd>
 
+
+      <dt><code>LegacyPrefixDocRoot</code></dt>
+      <dd>
+
+      <p>Prior to 2.4.25, if a substitution was an absolute URL that matched
+         the current virtual host, the URL might first be reduced to a URL-path
+         and then later reduced to a local path. Since the URL can be reduced 
+         to a local path, the path should be prefixed with the document root. 
+         This prevents a file such as /tmp/myfile from being accessed when a 
+         request is made to http://host/file/myfile with the following 
+         <directive module="mod_rewrite">RewriteRule</directive>.</p>
+      <highlight language="config">
+          RewriteRule /file/(.*) http://localhost/tmp/$1
+      </highlight>
+      <p>This option allows the old behavior to be used where the document
+         root is not prefixed to a local path that was reduced from a 
+         URL.  Available in 2.4.25 and later.</p>
+      </dd>
+
       </dl>
 </usage>
 
diff --git a/modules/mappers/mod_rewrite.c b/modules/mappers/mod_rewrite.c
index e026f38ca3..67d692a71b 100644
--- a/modules/mappers/mod_rewrite.c
+++ b/modules/mappers/mod_rewrite.c
@@ -202,6 +202,7 @@ static const char* really_last_key = "rewrite_really_last";
 #define OPTION_INHERIT_DOWN_BEFORE  (1<<7)
 #define OPTION_IGNORE_INHERIT       (1<<8)
 #define OPTION_IGNORE_CONTEXT_INFO  (1<<9)
+#define OPTION_LEGACY_PREFIX_DOCROOT (1<<10)
 
 #ifndef RAND_MAX
 #define RAND_MAX 32767
@@ -870,8 +871,15 @@ static void reduce_uri(request_rec *r)
 
         /* now check whether we could reduce it to a local path... */
         if (ap_matches_request_vhost(r, host, port)) {
+            rewrite_server_conf *conf = 
+                ap_get_module_config(r->server->module_config, &rewrite_module);
             rewritelog((r, 3, NULL, "reduce %s -> %s", r->filename, url));
             r->filename = apr_pstrdup(r->pool, url);
+
+            /* remember that the uri was reduced */
+            if(!(conf->options & OPTION_LEGACY_PREFIX_DOCROOT)) {
+                apr_table_setn(r->notes, "mod_rewrite_uri_reduced", "true");
+            }
         }
     }
 
@@ -3026,6 +3034,9 @@ static const char *cmd_rewriteoptions(cmd_parms *cmd,
         else if (!strcasecmp(w, "ignorecontextinfo")) {
             options |= OPTION_IGNORE_CONTEXT_INFO;
         }
+        else if (!strcasecmp(w, "legacyprefixdocroot")) {
+            options |= OPTION_LEGACY_PREFIX_DOCROOT;
+        }
         else {
             return apr_pstrcat(cmd->pool, "RewriteOptions: unknown option '",
                                w, "'", NULL);
@@ -4804,6 +4815,7 @@ static int hook_uri2file(request_rec *r)
         }
         else {
             /* it was finally rewritten to a local path */
+            const char *uri_reduced = NULL;
 
             /* expand "/~user" prefix */
 #if APR_HAS_USER
@@ -4839,7 +4851,12 @@ static int hook_uri2file(request_rec *r)
              * because we only do stat() on the first directory
              * and this gets cached by the kernel for along time!
              */
-            if (!prefix_stat(r->filename, r->pool)) {
+
+            if(!(conf->options & OPTION_LEGACY_PREFIX_DOCROOT)) {
+                uri_reduced = apr_table_get(r->notes, "mod_rewrite_uri_reduced");
+            }
+
+            if (!prefix_stat(r->filename, r->pool) || uri_reduced != NULL) {
                 int res;
                 char *tmp = r->uri;
 
-- 
2.40.0