From 0716cb868e847bb9f66c659f8662d905ba012de8 Mon Sep 17 00:00:00 2001
From: Sam Roberts <vieuxtech@gmail.com>
Date: Tue, 21 Feb 2012 13:13:46 -0800
Subject: [PATCH] Bounds check the argument to FD_SET

Failing to check the FD_SET argument against FD_SETSIZE causes
undefined behaviour (segfaults, for example).
---
 src/usocket.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/usocket.c b/src/usocket.c
index 3221cb9..f4c0a84 100644
--- a/src/usocket.c
+++ b/src/usocket.c
@@ -49,6 +49,7 @@ int socket_waitfd(p_socket ps, int sw, p_timeout tm) {
     fd_set rfds, wfds, *rp, *wp;
     struct timeval tv, *tp;
     double t;
+    if (*ps >= FD_SETSIZE) return EINVAL;
     if (timeout_iszero(tm)) return IO_TIMEOUT;  /* optimize timeout == 0 case */
     do {
         /* must set bits within loop, because select may have modifed them */