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diff --git a/src/util/unsafe.c b/src/util/unsafe.c
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+++ b/src/util/unsafe.c
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+/*++
+/* NAME
+/*	unsafe 3
+/* SUMMARY
+/*	are we running at non-user privileges
+/* SYNOPSIS
+/*	#include <safe.h>
+/*
+/*	int	unsafe()
+/* DESCRIPTION
+/*	The \fBunsafe()\fR routine attempts to determine if the process
+/*	(runs with privileges or has access to information) that the
+/*	controlling user has no access to. The purpose is to prevent
+/*	misuse of privileges, including access to protected information.
+/*
+/*	The result is always false when both of the following conditions
+/*	are true:
+/* .IP \(bu
+/*	The real UID is zero.
+/* .IP \(bu
+/*	The effective UID is zero.
+/* .PP
+/*	Otherwise, the result is true if any of the following conditions
+/*	is true:
+/* .IP \(bu
+/*	The issetuid kernel flag is non-zero (on systems that support
+/*	this concept).
+/* .IP \(bu
+/*	The real and effective user id differ.
+/* .IP \(bu
+/*	The real and effective group id differ.
+/* LICENSE
+/* .ad
+/* .fi
+/*	The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/*	Wietse Venema
+/*	IBM T.J. Watson Research
+/*	P.O. Box 704
+/*	Yorktown Heights, NY 10598, USA
+/*
+/*	Wietse Venema
+/*	Google, Inc.
+/*	111 8th Avenue
+/*	New York, NY 10011, USA
+/*--*/
+
+/* System library. */
+
+#include <sys_defs.h>
+#include <unistd.h>
+
+/* Utility library. */
+
+#include "safe.h"
+
+/* unsafe - can we trust user-provided environment, working directory, etc. */
+
+int     unsafe(void)
+{
+
+    /*
+     * The super-user is trusted.
+     */
+    if (getuid() == 0 && geteuid() == 0)
+	return (0);
+
+    /*
+     * Danger: don't trust inherited process attributes, and don't leak
+     * privileged info that the parent has no access to.
+     */
+    return (geteuid() != getuid()
+#ifdef HAS_ISSETUGID
+	    || issetugid()
+#endif
+	    || getgid() != getegid());
+}