diff --git a/src/openvpn/buffer.c b/src/openvpn/buffer.c
index bf38c68..87d3094 100644
--- a/src/openvpn/buffer.c
+++ b/src/openvpn/buffer.c
@@ -500,7 +500,7 @@
 void
 buf_null_terminate(struct buffer *buf)
 {
-    const char *last = (char *)BLAST(buf);
+    const uint8_t *last = BLAST(buf);
     if (last && *last == '\0') /* already terminated? */
     {
         return;
@@ -523,12 +523,12 @@
 {
     while (true)
     {
-        const char *last = (char *)BLAST(buf);
+        const uint8_t *last = BLAST(buf);
         if (!last)
         {
             break;
         }
-        if (char_class((unsigned char)*last, CC_CRLF | CC_NULL))
+        if (char_class(*last, CC_CRLF | CC_NULL))
         {
             if (!buf_inc_len(buf, -1))
             {