From 3d9d8819204c87f2f8deaf4d59937174a6465471 Mon Sep 17 00:00:00 2001
From: Hamish Coleman <hamish@zot.org>
Date: Sat, 9 Jul 2022 13:11:42 +0100
Subject: [PATCH] Guard against pointer overrun if sock is set negative

---
 src/edge_utils.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/edge_utils.c b/src/edge_utils.c
index 06d71e7..659b727 100644
--- a/src/edge_utils.c
+++ b/src/edge_utils.c
@@ -2869,7 +2869,7 @@ int run_edge_loop (n2n_edge_t *eee) {
             // any or all of the FDs could have input; check them all
 
             // external
-            if(FD_ISSET(eee->sock, &socket_mask)) {
+            if((eee->sock >= 0) && FD_ISSET(eee->sock, &socket_mask)) {
                 if(0 != fetch_and_eventually_process_data(eee, eee->sock,
                                                           pktbuf, &expected, &position,
                                                           now)) {