From 79d2ff2760d59fbaf2b4e1c040fcd211323fa052 Mon Sep 17 00:00:00 2001
From: John Safranek <john@wolfssl.com>
Date: Tue, 27 Oct 2020 09:38:02 -0700
Subject: [PATCH] KEX Packet Follows Fix 1. When filtering out the unknown
 names from name lists, the one that    will be the client's guess KEX type
 can get removed if unknown. Let    the first item in the client's list be
 added if unknown.

---
 src/internal.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/internal.c b/src/internal.c
index cdd5dfb..5892ab2 100644
--- a/src/internal.c
+++ b/src/internal.c
@@ -1914,7 +1914,10 @@ static int GetNameList(byte* idList, word32* idListSz,
                         WLOG(WS_LOG_DEBUG, "DNL: name ID = %s", displayName);
                     }
                 }
-                if (id != ID_UNKNOWN) {
+                if (id != ID_UNKNOWN || idListIdx == 0) {
+                    /* Intentionally save the first one if unknown. This helps
+                     * skipping the KexDhInit if the client sends the wrong one
+                     * as a guess. */
                     if (idListIdx >= *idListSz) {
                         WLOG(WS_LOG_ERROR, "No more space left for names");
                         return WS_BUFFER_E;