Security fix for CVE-2009-1890:

* modules/proxy/mod_proxy_http.c (stream_reqbody_cl): Specify the base
  passed to apr_strtoff, and validate the Content-Length in the same
  way the HTTP_IN filter does.  If the number of bytes streamed
  exceeds the expected body length, bail out of the loop.

Thanks to: Toadie <toadie643 gmail.com> for reporting and diagnosis of
	this issue.
Submitted by: niq, jorton

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@790587 13f79535-47bb-0310-9956-ffa450edef68

diff --git a/CHANGES b/CHANGES
index 6d911b4bc804a19c5c19221f408228dd31318ec5..9ddb556e7e32991017ec722722e521c595190fa2 100644 (file)
--- a/CHANGES
+++ b/CHANGES
@@ -2,6 +2,11 @@
 
 Changes with Apache 2.3.3
 
+  *) SECURITY: CVE-2009-1890 (cve.mitre.org) 
+     Fix a potential Denial-of-Service attack against mod_proxy in a
+     reverse proxy configuration, where a remote attacker can force a
+     proxy process to consume CPU time indefinitely.  [Nick Kew, Joe Orton]
+
   *) SECURITY: CVE-2009-1191 (cve.mitre.org)
      mod_proxy_ajp: Avoid delivering content from a previous request which
      failed to send a request body. PR 46949 [Ruediger Pluem]

diff --git a/modules/proxy/mod_proxy_http.c b/modules/proxy/mod_proxy_http.c
index bc59aadc3d8bd65f40034e71891725e93181ddaa..bdfe594d69f78b1a995296ac5a2c6771ebbeeedd 100644 (file)
--- a/modules/proxy/mod_proxy_http.c
+++ b/modules/proxy/mod_proxy_http.c
@@ -427,10 +427,16 @@ static int stream_reqbody_cl(apr_pool_t *p,
     apr_off_t bytes_streamed = 0;
 
     if (old_cl_val) {
+        char *endstr;
+
         add_cl(p, bucket_alloc, header_brigade, old_cl_val);
-        if (APR_SUCCESS != (status = apr_strtoff(&cl_val, old_cl_val, NULL,
-                                                 0))) {
-            return HTTP_INTERNAL_SERVER_ERROR;
+        status = apr_strtoff(&cl_val, old_cl_val, &endstr, 10);
+        
+        if (status || *endstr || endstr == old_cl_val || cl_val < 0) {
+            ap_log_rerror(APLOG_MARK, APLOG_ERR, status, r,
+                          "proxy: could not parse request Content-Length (%s)",
+                          old_cl_val);
+            return HTTP_BAD_REQUEST;
         }
     }
     terminate_headers(bucket_alloc, header_brigade);
@@ -463,8 +469,13 @@ static int stream_reqbody_cl(apr_pool_t *p,
          *
          * Prevents HTTP Response Splitting.
          */
-        if (bytes_streamed > cl_val)
-             continue;
+        if (bytes_streamed > cl_val) {
+            ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
+                          "proxy: read more bytes of request body than expected "
+                          "(got %" APR_OFF_T_FMT ", expected %" APR_OFF_T_FMT ")",
+                          bytes_streamed, cl_val);
+            return HTTP_INTERNAL_SERVER_ERROR;
+        }
 
         if (header_brigade) {
             /* we never sent the header brigade, so go ahead and