2004-03-13  Dmitry V. Levin  <ldv@altlinux.org>

	Improve chroot jailing support.

	* common/common.c:

	(become_user): Moved initgroups call from here ...

	(get_user_pwent): ... to here.

	(chroot_start): Call tzset(3) before chroot(2) call.

	Preopen /dev/null before chroot(2) call ...

	(background): ... and use the descriptor for redirection.

	(background): Do not close standard descriptors in parent process.

--- nut-2.0.0/common/common.c.orig	2004-03-08 15:09:54 +0300

+++ nut-2.0.0/common/common.c	2004-04-04 23:53:38 +0400

@@ -26,6 +26,7 @@

 	int	nut_debug_level = 0;

 	static	int	upslog_flags = UPSLOG_STDERR;

+	static	int	null_fd = -1;

 static void xbit_set(int *val, int flag)

 {

@@ -66,28 +67,29 @@

 /* close ttys and become a daemon */

 void background(void)

 {

-	int	pid;

+	int fd;

+	pid_t	pid;

 	if ((pid = fork()) < 0)

 		fatal("Unable to enter background");

-	xbit_set(&upslog_flags, UPSLOG_SYSLOG);

-	xbit_clear(&upslog_flags, UPSLOG_STDERR);

-

-	close(0);

-	close(1);

-	close(2);

-

 	if (pid != 0) 

 		_exit(EXIT_SUCCESS);		/* parent */

 	/* child */

+	xbit_set(&upslog_flags, UPSLOG_SYSLOG);

+	xbit_clear(&upslog_flags, UPSLOG_STDERR);

+

 	/* make fds 0-2 point somewhere defined */

-	if (open("/dev/null", O_RDWR) != 0)

+	if ((null_fd < 0) && ((null_fd = open("/dev/null", O_RDWR)) < 0))

 		fatal("open /dev/null");

-	dup(0);

-	dup(0);

+	for (fd = 0; fd<= 2; ++fd)

+		if ((null_fd != fd) && (dup2(null_fd, fd) < 0))

+			fatal("dup2 /dev/null");

+	if ((null_fd > 2) && (close(null_fd) < 0))

+		fatal("close /dev/null");

+	null_fd = -1;

 #ifdef HAVE_SETSID

 	setsid();		/* make a new session to dodge signals */

@@ -99,7 +101,12 @@

 /* do this here to keep pwd/grp stuff out of the main files */

 struct passwd *get_user_pwent(const char *name)

 {

-	return getpwnam(name);

+	struct passwd *pw = getpwnam(name);

+

+	if (pw && !geteuid() && initgroups(pw->pw_name, pw->pw_gid) == -1)

+		fatal("initgroups");

+

+	return pw;

 }

 /* change to the user defined in the struct */

@@ -113,9 +120,6 @@ void become_user(struct passwd *pw)

 		if (seteuid(0))

 			fatal("getuid gave 0, but seteuid(0) failed");

-	if (initgroups(pw->pw_name, pw->pw_gid) == -1)

-		fatal("initgroups");

-

 	if (setgid(pw->pw_gid) == -1)

 		fatal("setgid");

@@ -126,6 +130,11 @@

 /* drop down into a directory and throw away pointers to the old path */

 void chroot_start(const char *path)

 {

+	tzset();

+	

+	if ((null_fd = open("/dev/null", O_RDWR)) < 0)

+		fatal("open /dev/null");

+

 	if (chdir(path))

 		fatal("chdir(%s)", path);