Index: modules/http/http_protocol.c
===================================================================
--- modules/http/http_protocol.c	(revision 1373281)
+++ modules/http/http_protocol.c	(working copy)
@@ -299,9 +299,10 @@
     /* All of our comparisons must be in seconds, because that's the
      * highest time resolution the HTTP specification allows.
      */
-    /* XXX: we should define a "time unset" constant */
-    tmp_time = ((r->mtime != 0) ? r->mtime : apr_time_now());
-    mtime =  apr_time_sec(tmp_time);
+    /* XXX: we should define a "time unset" constant
+     * XXX: meanwhile we interpret 0 as unset
+     */
+    mtime = apr_time_sec(r->mtime);
 
     /* If an If-Match request-header field was given
      * AND the field value is not "*" (meaning match anything)
@@ -325,7 +326,8 @@
         if (if_unmodified != NULL) {
             apr_time_t ius = apr_date_parse_http(if_unmodified);
 
-            if ((ius != APR_DATE_BAD) && (mtime > apr_time_sec(ius))) {
+            if ((ius != APR_DATE_BAD)
+                && (mtime == 0 || mtime > apr_time_sec(ius))) {
                 return HTTP_PRECONDITION_FAILED;
             }
         }
@@ -376,6 +378,7 @@
      * A date later than the server's current request time is invalid.
      */
     if (r->method_number == M_GET
+        && (mtime != 0)
         && (not_modified || !if_nonematch)
         && (if_modified_since =
               apr_table_get(r->headers_in,
@@ -384,10 +387,13 @@
         apr_int64_t ims, reqtime;
 
         ims_time = apr_date_parse_http(if_modified_since);
-        ims = apr_time_sec(ims_time);
-        reqtime = apr_time_sec(r->request_time);
 
-        not_modified = ims >= mtime && ims <= reqtime;
+        if (ims_time != APR_DATE_BAD) {
+            ims = apr_time_sec(ims_time);
+            reqtime = apr_time_sec(r->request_time);
+
+            not_modified = ims >= mtime && ims <= reqtime;
+        }
     }
 
     if (not_modified) {