1 files changed, 6 insertions, 1 deletions
diff --git a/generic/tclBinary.c b/generic/tclBinary.c
index f321b28..8c95305 100644
--- a/generic/tclBinary.c
+++ b/generic/tclBinary.c
@@ -273,10 +273,15 @@ Tcl_SetByteArrayObj(
     TclFreeIntRep(objPtr);
     Tcl_InvalidateStringRep(objPtr);
 
+    if (length < 0) {
+	length = 0;
+    }
     byteArrayPtr = (ByteArray *) ckalloc(BYTEARRAY_SIZE(length));
     byteArrayPtr->used = length;
     byteArrayPtr->allocated = length;
-    memcpy(byteArrayPtr->bytes, bytes, (size_t) length);
+    if (length && bytes) {
+	memcpy(byteArrayPtr->bytes, bytes, (size_t) length);
+    }
 
     objPtr->typePtr = &tclByteArrayType;
     SET_BYTEARRAY(objPtr, byteArrayPtr);