From 2454682ee3e534fdacd5897e5f911d93060ece87 Mon Sep 17 00:00:00 2001
From: aafbsd <45147422+aafbsd@users.noreply.github.com>
Date: Sun, 22 Dec 2024 08:35:03 +0000
Subject: [PATCH] Fix: do not use strlcpy() if buffers overlap

This resulted in messed up d= tags on FreeBSD. The result was that mails using the SubDomains feature were signed improperly.
---
 opendkim/opendkim.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/opendkim/opendkim.c b/opendkim/opendkim.c
index 803f37b0..eaa1c086 100644
--- a/opendkim/opendkim.c
+++ b/opendkim/opendkim.c
@@ -12303,8 +12303,10 @@ mlfi_eoh(SMFICTX *ctx)
 
 				if (domainok)
 				{
-					strlcpy((char *) dfc->mctx_domain, p,
-					        sizeof dfc->mctx_domain);
+					// We must not use strlcpy() here since
+					// src and dst overlap.
+					char* p2 = dfc->mctx_domain;
+					while( (*p2++ = *p++) );
 					break;
 				}
 			}