From 110f5cb4427de0471b4bccaca29a29823aa6fa8e Mon Sep 17 00:00:00 2001
From: Andrew Hutchings <andrew@wolfssl.com>
Date: Thu, 26 Feb 2026 14:09:01 +0000
Subject: [PATCH] Fix ECH error code: use BUFFER_ERROR for malformed peer input

Change innerClientHelloLen underflow guard in TLSX_ECH_Parse from
BAD_FUNC_ARG to BUFFER_ERROR to match the convention used throughout
tls.c for wire-protocol length/bounds validation.
---
 src/tls.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/tls.c b/src/tls.c
index a4f83e0867..d0f7c9ea2a 100644
--- a/src/tls.c
+++ b/src/tls.c
@@ -13606,7 +13606,7 @@ static int TLSX_ECH_Parse(WOLFSSL* ssl, const byte* readBuf, word16 size,
         /* read hello inner len */
         ato16(readBuf_p, &ech->innerClientHelloLen);
         if (ech->innerClientHelloLen < WC_AES_BLOCK_SIZE) {
-            return BAD_FUNC_ARG;
+            return BUFFER_ERROR;
         }
         ech->innerClientHelloLen -= WC_AES_BLOCK_SIZE;
         readBuf_p += 2;