From ad5138a341ff611963122942ff600dcfb667cc5b Mon Sep 17 00:00:00 2001
From: Niels Dossche <7771979+nielsdos@users.noreply.github.com>
Date: Sun, 19 May 2024 22:54:06 +0200
Subject: [PATCH] Fix undefined behaviour in fastcgi.c (#14269)

Arithmetic on NULL pointers is undefined.
---
 main/fastcgi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/main/fastcgi.c b/main/fastcgi.c
index 85e73f2d8bf..18eb4b394bc 100644
--- a/main/fastcgi.c
+++ b/main/fastcgi.c
@@ -744,7 +744,7 @@ int fcgi_listen(const char *path, int backlog)
 		memset(&sa.sa_unix, 0, sizeof(sa.sa_unix));
 		sa.sa_unix.sun_family = AF_UNIX;
 		memcpy(sa.sa_unix.sun_path, path, path_len + 1);
-		sock_len = (size_t)(((struct sockaddr_un *)0)->sun_path)	+ path_len;
+		sock_len = XtOffsetOf(struct sockaddr_un, sun_path) + path_len;
 #ifdef HAVE_SOCKADDR_UN_SUN_LEN
 		sa.sa_unix.sun_len = sock_len;
 #endif