1 files changed, 63 insertions, 16 deletions

diff --git a/modules/http/http_request.c b/modules/http/http_request.c
index 3a7e5ef9..251aa33b 100644
--- a/modules/http/http_request.c
+++ b/modules/http/http_request.c
@@ -399,16 +399,46 @@ static request_rec *internal_internal_redirect(const char *new_uri,
     new->proto_output_filters  = r->proto_output_filters;
     new->proto_input_filters   = r->proto_input_filters;
 
-    new->output_filters  = new->proto_output_filters;
     new->input_filters   = new->proto_input_filters;
 
     if (new->main) {
-        /* Add back the subrequest filter, which we lost when
-         * we set output_filters to include only the protocol
-         * output filters from the original request.
-         */
-        ap_add_output_filter_handle(ap_subreq_core_filter_handle,
-                                    NULL, new, new->connection);
+        ap_filter_t *f, *nextf;
+
+        /* If this is a subrequest, the filter chain may contain a
+         * mixture of filters specific to the old request (r), and
+         * some inherited from r->main.  Here, inherit that filter
+         * chain, and remove all those which are specific to the old
+         * request; ensuring the subreq filter is left in place. */
+        new->output_filters = r->output_filters;
+
+        f = new->output_filters;
+        do {
+            nextf = f->next;
+
+            if (f->r == r && f->frec != ap_subreq_core_filter_handle) {
+                ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r,
+                              "dropping filter '%s' in internal redirect from %s to %s",
+                              f->frec->name, r->unparsed_uri, new_uri);
+
+                /* To remove the filter, first set f->r to the *new*
+                 * request_rec, so that ->output_filters on 'new' is
+                 * changed (if necessary) when removing the filter. */
+                f->r = new;
+                ap_remove_output_filter(f);
+            }
+
+            f = nextf;
+
+            /* Stop at the protocol filters.  If a protocol filter has
+             * been newly installed for this resource, better leave it
+             * in place, though it's probably a misconfiguration or
+             * filter bug to get into this state. */
+        } while (f && f != new->proto_output_filters);
+    }
+    else {
+        /* If this is not a subrequest, clear out all
+         * resource-specific filters. */
+        new->output_filters  = new->proto_output_filters;
     }
 
     update_r_in_filters(new->input_filters, r, new);
@@ -466,15 +496,6 @@ AP_DECLARE(void) ap_internal_fast_redirect(request_rec *rr, request_rec *r)
     r->output_filters = rr->output_filters;
     r->input_filters = rr->input_filters;
 
-    if (r->main) {
-        ap_add_output_filter_handle(ap_subreq_core_filter_handle,
-                                    NULL, r, r->connection);
-    }
-    else if (r->output_filters->frec == ap_subreq_core_filter_handle) {
-        ap_remove_output_filter(r->output_filters);
-        r->output_filters = r->output_filters->next;
-    }
-
     /* If any filters pointed at the now-defunct rr, we must point them
      * at our "new" instance of r.  In particular, some of rr's structures
      * will now be bogus (say rr->headers_out).  If a filter tried to modify
@@ -483,6 +504,32 @@ AP_DECLARE(void) ap_internal_fast_redirect(request_rec *rr, request_rec *r)
      */
     update_r_in_filters(r->input_filters, rr, r);
     update_r_in_filters(r->output_filters, rr, r);
+
+    if (r->main) {
+        ap_add_output_filter_handle(ap_subreq_core_filter_handle,
+                                    NULL, r, r->connection);
+    }
+    else {
+        /*
+         * We need to check if we now have the SUBREQ_CORE filter in our filter
+         * chain. If this is the case we need to remove it since we are NO
+         * subrequest. But we need to keep in mind that the SUBREQ_CORE filter
+         * does not necessarily need to be the first filter in our chain. So we
+         * need to go through the chain. But we only need to walk up the chain
+         * until the proto_output_filters as the SUBREQ_CORE filter is below the
+         * protocol filters.
+         */
+        ap_filter_t *next;
+
+        next = r->output_filters;
+        while (next && (next->frec != ap_subreq_core_filter_handle)
+               && (next != r->proto_output_filters)) {
+                next = next->next;
+        }
+        if (next && (next->frec == ap_subreq_core_filter_handle)) {
+            ap_remove_output_filter(next);
+        }
+    }
 }
 
 AP_DECLARE(void) ap_internal_redirect(const char *new_uri, request_rec *r)