py/binary: Change internal bytearray typecode from 0 to 1.

The value of 0 can't be used because otherwise mp_binary_get_size will let
a null byte through as the type code (intepreted as byterray).  This can
lead to invalid type-specifier strings being let through without an error
in the struct module, and even buffer overruns.

1 files changed, 3 insertions, 2 deletions

diff --git a/py/binary.h b/py/binary.h
index 7b5c60f1a..0dae6a29e 100644
--- a/py/binary.h
+++ b/py/binary.h
@@ -29,8 +29,9 @@
 #include "py/obj.h"
 
 // Use special typecode to differentiate repr() of bytearray vs array.array('B')
-// (underlyingly they're same).
-#define BYTEARRAY_TYPECODE 0
+// (underlyingly they're same).  Can't use 0 here because that's used to detect
+// type-specification errors due to end-of-string.
+#define BYTEARRAY_TYPECODE 1
 
 size_t mp_binary_get_size(char struct_type, char val_type, mp_uint_t *palign);
 mp_obj_t mp_binary_get_val_array(char typecode, void *p, mp_uint_t index);