Make extra sure that authbuf can't overflow.
diff --git a/socket.c b/socket.c
index c850cd3..8a96061 100644
--- a/socket.c
+++ b/socket.c
@@ -58,7 +58,7 @@
 			 proxy_user, ":", proxy_pass, NULL);
 		len = strlen(buffer);
 
-		if ((len*8 + 5) / 6 >= (int)sizeof authbuf) {
+		if ((len*8 + 5) / 6 >= (int)sizeof authbuf - 3) {
 			rprintf(FERROR,
 				"authentication information is too long\n");
 			return -1;