Fix overflow in mangle_dupechar_last function

OpenCL/inc_rp.cl

@@ -503,6 +503,7 @@ static int mangle_dupechar_last (MAYBE_UNUSED const u8 p0, MAYBE_UNUSED const u8
 {
   const int out_len = len + p0;
 
+  if (len     ==                0) return (len);
   if (out_len >= RP_PASSWORD_SIZE) return (len);
 
   const u8 c = buf[len - 1];

docs/changes.txt

@@ -41,6 +41,7 @@
 - Fixed the output of --show when used together with the collider modes -m 9710, 9810 or 10410
 - Fixed the use of --veracrypt-pim option. It was completely ignored without showing an error
 - Fixed the version number used in the restore file header
+- Fixed overflow in mangle_dupechar_last function
 
 ##
 ## Improvements

src/rp_kernel_on_cpu.c

@@ -528,6 +528,7 @@ static int mangle_dupechar_last (MAYBE_UNUSED const u8 p0, MAYBE_UNUSED const u8
 {
   const int out_len = len + p0;
 
+  if (len     ==                0) return (len);
   if (out_len >= RP_PASSWORD_SIZE) return (len);
 
   const u8 c = buf[len - 1];