max active locks

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1938651 13f79535-47bb-0310-9956-ffa450edef68

Author: covener

modules/dav/main/mod_dav.h

@@ -59,6 +59,9 @@ extern "C" {
 #define DAV_DO_COPY             0
 #define DAV_DO_MOVE             1
 
+#ifndef DAV_MAX_SHARED_LOCKS
+#define DAV_MAX_SHARED_LOCKS (1024)
+#endif
 
 #if 1
 #define DAV_DEBUG        1

modules/dav/main/util.c

@@ -1042,6 +1042,8 @@ static dav_error * dav_validate_resource_state(apr_pool_t *p,
         seen_locktoken = 1;
     }
     else if (flags & DAV_LOCKSCOPE_SHARED) {
+        unsigned count = 0;
+
         /*
         ** Strictly speaking, we don't need this loop. Either the first
         ** (and only) lock will be EXCLUSIVE, or none of them will be.
@@ -1052,6 +1054,13 @@ static dav_error * dav_validate_resource_state(apr_pool_t *p,
                                      "The requested resource is already "
                                      "locked exclusively.");
             }
+            /* Impose a maximum count of shared locks since the lock
+             * list is used in a linear-cost scan in many places. */
+            else if (count++ > DAV_MAX_SHARED_LOCKS) {
+                return dav_new_error(p, HTTP_FORBIDDEN, 0, 0,
+                                     "The maximum shared lock count has "
+                                     "been reached.");
+            }
         }
 
         /*