From 123cfe3ab499f0d7805aa64c43070c1cc856cd86 Mon Sep 17 00:00:00 2001
From: Felix Schladt <82309717+FelixSchladt@users.noreply.github.com>
Date: Mon, 19 Feb 2024 14:28:50 +0100
Subject: [PATCH] Correct the MSS option size check

---
 modules/pico_tcp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/modules/pico_tcp.c b/modules/pico_tcp.c
index f24ee3db..7bcefe3c 100644
--- a/modules/pico_tcp.c
+++ b/modules/pico_tcp.c
@@ -868,7 +868,7 @@ static inline void tcp_parse_option_mss(struct pico_socket_tcp *t, uint8_t len,
     if (tcpopt_len_check(idx, len, PICO_TCPOPTLEN_MSS) < 0)
         return;
 
-    if ((*idx + PICO_TCPOPTLEN_MSS) > len)
+    if ((*idx + PICO_TCPOPTLEN_MSS - 2) > len)
         return;
 
     t->mss_ok = 1;