This bug was never noticed, because 10.6+ uses pam,
and the fallback is redundant. On 10.5 original code fails:
socket.c:1224:13: error: implicit declaration of function 'getpwnam_shadow' [-Wimplicit-function-declaration]
socket.c:1224:11: error: assignment to 'struct passwd *' from 'int' makes pointer from integer without a cast [-Wint-conversion]

--- socket.c
+++ socket.c	2025-07-22 16:54:39.000000000 +0800
@@ -1208,7 +1208,7 @@
 	bool ret = false;
 	char *passwd = 0;
 
-#ifndef _PWD_H
+#ifdef _PWD_H_
 	struct passwd *p;
 #else
 	struct spwd *p;
@@ -1220,8 +1220,8 @@
 	if (seteuid(0) || setegid(0))
 		Panic(0, "\r\ncan't get root uid/gid\r\n");
 
-#ifndef _PWD_H
-	p = getpwnam_shadow(ppp->pw_name);
+#ifdef _PWD_H_
+	p = getpwnam(ppp->pw_name);
 #else
 	p = getspnam(ppp->pw_name);
 #endif
@@ -1235,7 +1235,7 @@
 		AddStr("\r\ncan't open passwd file\r\n");
 		return false;
 	}
-#ifndef _PWD_H
+#ifdef _PWD_H_
 	passwd = crypt(password, p->pw_passwd);
 	ret    = (strcmp(passwd, p->pw_passwd) == 0);
 #else