From c97c3571a009ee9f80b04880c721be012f458db5 Mon Sep 17 00:00:00 2001
From: Francois-Xavier Le Bail <devel.fx.lebail@orange.fr>
Date: Wed, 6 Mar 2019 14:52:14 +0100
Subject: [PATCH] TCP: Fix an undefined behavior at runtime

The error was:
print-tcp.c:831:22: runtime error: unsigned integer overflow: 0 - 1
cannot be represented in type 'u_int' (aka 'unsigned int')
---
 print-tcp.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/print-tcp.c b/print-tcp.c
index 1b8fb4c4..d2cb1520 100644
--- a/print-tcp.c
+++ b/print-tcp.c
@@ -828,10 +828,11 @@ print_tcp_rst_data(netdissect_options *ndo,
                 ND_PRINT("+");			/* indicate we truncate */
         }
         ND_PRINT(" ");
-        while (length-- && sp < ndo->ndo_snapend) {
+        while (length && sp < ndo->ndo_snapend) {
                 c = EXTRACT_U_1(sp);
                 sp++;
                 fn_print_char(ndo, c);
+		length--;
         }
         ND_PRINT("]");
 }
-- 
2.39.5