diff --git a/mercurial/manifest.py b/mercurial/manifest.py
--- a/mercurial/manifest.py
+++ b/mercurial/manifest.py
@@ -138,6 +138,10 @@ class manifest(revlog):
             return "".join([struct.pack(">lll", d[0], d[1], len(d[2])) + d[2] \
                             for d in x ])
 
+        def checkforbidden(f):
+            if '\n' in f or '\r' in f:
+                raise RevlogError(_("'\\n' and '\\r' disallowed in filenames"))
+
         # if we're using the listcache, make sure it is valid and
         # parented by the same node we're diffing against
         if not changed or not self.listcache or not p1 or \
@@ -145,6 +149,9 @@ class manifest(revlog):
             files = map.keys()
             files.sort()
 
+            for f in files:
+                checkforbidden(f)
+
             # if this is changed to support newlines in filenames,
             # be sure to check the templates/ dir again (especially *-raw.tmpl)
             text = ["%s\000%s%s\n" % (f, hex(map[f]), map.flags(f)) for f in files]
@@ -153,6 +160,8 @@ class manifest(revlog):
         else:
             addlist = self.listcache
 
+            for f in changed[0]:
+                checkforbidden(f)
             # combine the changed lists into one list for sorting
             work = [[x, 0] for x in changed[0]]
             work[len(work):] = [[x, 1] for x in changed[1]]