From bdaca6afc6bc7b9a92f0fa6a1a2c18fb7da7bb54 Mon Sep 17 00:00:00 2001
From: Oldes <oldes.huhuman@gmail.com>
Date: Sat, 31 Oct 2020 13:02:38 +0100
Subject: [PATCH] FIX: Crash when loading specially crafted binary

fixes: https://github.com/Oldes/Rebol-issues/issues/2435
---
 src/core/s-crc.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/core/s-crc.c b/src/core/s-crc.c
index 77b7eb14e0..7a01a96130 100644
--- a/src/core/s-crc.c
+++ b/src/core/s-crc.c
@@ -169,7 +169,11 @@ static REBCNT *CRC32_Table = 0;
 
 	for (; ulen > 0; str++, ulen--) {
 		n = *str;
-		if (n > 127 && NZ(m = Decode_UTF8_Char(&str, &ulen))) n = m; // mods str, ulen
+		if (n > 127) {
+			m = Decode_UTF8_Char(&str, &ulen); // mods str, ulen
+			if (!m) Trap0(RE_INVALID_CHARS);
+			n = m; 
+		}
 		if (n < UNICODE_CASES) n = LO_CASE(n);
 		n = (REBYTE)((hash >> CRCSHIFTS) ^ (REBYTE)n); // drop upper 8 bits
 		hash = MASK_CRC(hash << 8) ^ (REBINT)CRC24_Table[n];