If su(1) is run without an effective uid of 0, generate an error to

the user indicating that su is not running setuid, which may help
suggest to the user that it should be setuid, or should not be
running from a file system mounted nosuid.

Suggsted by:	Ivan Voras <ivoras at fer dot hr>
MFC after:	2 weeks

1 files changed, 33 insertions, 3 deletions

diff --git a/usr.bin/su/su.c b/usr.bin/su/su.c
index 57122e2..f6e0c86 100644
--- a/usr.bin/su/su.c
+++ b/usr.bin/su/su.c
@@ -1,7 +1,5 @@
 /*
- * Copyright (c) 1988, 1993, 1994
- *	The Regents of the University of California.  All rights reserved.
- * Copyright (c) 2002 Networks Associates Technologies, Inc.
+ * Copyright (c) 2002, 2005 Networks Associates Technologies, Inc.
  * All rights reserved.
  *
  * Portions of this software were developed for the FreeBSD Project by
@@ -17,6 +15,31 @@
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+/*-
+ * Copyright (c) 1988, 1993, 1994
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
  * 3. All advertising materials mentioning features or use of this software
  *    must display the following acknowledgement:
  *	This product includes software developed by the University of
@@ -184,6 +207,13 @@ main(int argc, char *argv[])
 	if (strlen(user) > MAXLOGNAME - 1)
 		errx(1, "username too long");
 
+	/*
+	 * Try to provide more helpful debugging output if su(1) is running
+	 * non-setuid, or was run from a file system not mounted setuid.
+	 */
+	if (geteuid() != 0)
+		errx(1, "not running setuid");
+
 	nargv = malloc(sizeof(char *) * (size_t)(argc + 4));
 	if (nargv == NULL)
 		errx(1, "malloc failure");