From c336121fb5a5c1b9cb9b2cd4cea50f0788270505 Mon Sep 17 00:00:00 2001
From: Brian Wellington <source@isc.org>
Date: Fri, 7 Jul 2000 23:53:35 +0000
Subject: [PATCH] Hopefully the last change to the setuid code.  Only call
 initgroups() if getuid() == 0.  Don't call ns_os_changeuser() more than once
 (it could happen on Linux).

The code in its current form doesn't check for root before calling
setgid() or setuid(), since they'll fail and print reasonable error
messages (unless -u is supplied with the non-root user that ran named,
in which case it would succeed).  The call to initgroups() would fail for
non root, so it shouldn't be tried.

The previous (as of a few days ago) code just ignored the -u parameter
when named was run as non-root.  This was not good.
---
 bin/named/unix/os.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/bin/named/unix/os.c b/bin/named/unix/os.c
index dcae3d1f81..e9ae0584b6 100644
--- a/bin/named/unix/os.c
+++ b/bin/named/unix/os.c
@@ -15,7 +15,7 @@
  * SOFTWARE.
  */
 
-/* $Id: os.c,v 1.24 2000/07/07 22:10:54 bwelling Exp $ */
+/* $Id: os.c,v 1.25 2000/07/07 23:53:35 bwelling Exp $ */
 
 #include <config.h>
 
@@ -44,6 +44,7 @@ static isc_boolean_t non_root = ISC_FALSE;
 #endif
 
 static struct passwd *runas_pw = NULL;
+static isc_boolean_t done_setuid = ISC_FALSE;
 
 #ifdef HAVE_LINUX_CAPABILITY_H
 
@@ -263,7 +264,7 @@ ns_os_chroot(const char *root) {
 
 void
 ns_os_inituserinfo(const char *username) {
-	if (username == NULL || getuid() != 0)
+	if (username == NULL)
 		return;
 
 	if (all_digits(username))
@@ -278,17 +279,21 @@ ns_os_inituserinfo(const char *username) {
 
 void
 ns_os_changeuser(void) {
-	if (runas_pw == NULL)
+	if (runas_pw == NULL || done_setuid)
 		return;
 
+	done_setuid = ISC_TRUE;
+
 #ifdef HAVE_LINUXTHREADS
 	if (!non_root_caps)
 		ns_main_earlyfatal(
 		   "-u not supported on Linux kernels older than 2.3.99-pre3");
 #endif	
 
-	if (initgroups(runas_pw->pw_name, runas_pw->pw_gid) < 0)
-		ns_main_earlyfatal("initgroups(): %s", strerror(errno));
+	if (getuid() == 0) {
+		if (initgroups(runas_pw->pw_name, runas_pw->pw_gid) < 0)
+			ns_main_earlyfatal("initgroups(): %s", strerror(errno));
+	}
 
 	if (setgid(runas_pw->pw_gid) < 0)
 		ns_main_earlyfatal("setgid(): %s", strerror(errno));