Unfix the fix for an off-by-zero.

arg_ulong_index_integer(argno, n) takes n as _exclusive_ upper bound.

In this case, n - 64 is a valid starting index.  So the exclusive
upper bound is n - 64 + 1 = n - 63.

diff --git a/src/microcode/prchacha.c b/src/microcode/prchacha.c
index 1bfa74fe49ef7e002dc0e28764fb43e98839eccd..bc77900f175f421692aa97b6ab4eaa97dc0fef46 100644 (file)
--- a/src/microcode/prchacha.c
+++ b/src/microcode/prchacha.c
@@ -36,7 +36,7 @@ do_chacha_core (void (*core) (uint8_t *, const uint8_t *, const uint8_t *,
   if (noutput < 64)
     error_bad_range_arg (1);
 
-  unsigned long offset = (arg_ulong_index_integer (2, (noutput - 64)));
+  unsigned long offset = (arg_ulong_index_integer (2, (noutput - 64 + 1)));
 
   unsigned long ninput;
   const uint8_t * input = (arg_bytevector (3, (&ninput)));