From e6d4b388b9b5268be5e9cfe7c080c94084947315 Mon Sep 17 00:00:00 2001
From: Tom Rhodes <trhodes@FreeBSD.org>
Date: Mon, 19 Mar 2007 12:12:53 +0000
Subject: [PATCH] Improve previous commit by using setusercontext(3) and
 removing the group option.  Bump doc date for manual page changes.

Reviewed by:	rwatson, ru, will (older version)
---
 usr.sbin/daemon/daemon.8 | 15 +++++-------
 usr.sbin/daemon/daemon.c | 52 +++++++++++++---------------------------
 2 files changed, 23 insertions(+), 44 deletions(-)

diff --git a/usr.sbin/daemon/daemon.8 b/usr.sbin/daemon/daemon.8
index e94834f6f3c2..c284427fab36 100644
--- a/usr.sbin/daemon/daemon.8
+++ b/usr.sbin/daemon/daemon.8
@@ -26,7 +26,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd March 9, 2007
+.Dd March 19, 2007
 .Dt DAEMON 8
 .Os
 .Sh NAME
@@ -35,16 +35,15 @@
 .Sh SYNOPSIS
 .Nm
 .Op Fl cf
-.Op Fl u Ar user
-.Op Fl g Ar group
 .Op Fl p Ar pidfile
+.Op Fl u Ar user
 .Ar command arguments ...
 .Sh DESCRIPTION
 The
 .Nm
 utility detaches itself from the controlling terminal and
 executes the program specified by its arguments.
-Privileges may be lowered to specified user and/or group.
+Privileges may be lowered to the specified user.
 .Pp
 The options are as follows:
 .Bl -tag -width indent
@@ -54,19 +53,17 @@ Change the current working directory to the root
 .It Fl f
 Redirect standard input, standard output and standard error to
 .Pa /dev/null .
-.It Fl g Ar group
-Drop privileges to specified group.
 .It Fl p Ar file
 Write the ID of the created process into the
 .Ar file
-using
-.It Fl u Ar user
-Drop privileges to specified user.
+using the
 .Xr pidfile 3
 functionality.
 Note, that the file will be created shortly before the process is
 actually executed, and will remain after the process exits (although
 it will be removed if the execution fails).
+.It Fl u Ar user
+Run the program with the rights of user specified, requires privilege.
 .El
 .Sh EXIT STATUS
 The
diff --git a/usr.sbin/daemon/daemon.c b/usr.sbin/daemon/daemon.c
index 43c6f8ca4f85..4fca144b498b 100644
--- a/usr.sbin/daemon/daemon.c
+++ b/usr.sbin/daemon/daemon.c
@@ -36,13 +36,13 @@ __FBSDID("$FreeBSD$");
 #include <err.h>
 #include <errno.h>
 #include <pwd.h>
-#include <grp.h>
 #include <libutil.h>
+#include <login_cap.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
 
-static void restrict_process(const char *, const char *);
+static void restrict_process(const char *);
 static void usage(void);
 
 int
@@ -50,12 +50,12 @@ main(int argc, char *argv[])
 {
 	struct pidfh *pfh = NULL;
 	int ch, nochdir, noclose, errcode;
-	const char *pidfile, *user, *group;
+	const char *pidfile, *user;
 	pid_t otherpid;
 
 	nochdir = noclose = 1;
-	pidfile = user = group = NULL;
-	while ((ch = getopt(argc, argv, "-cfg:p:u:")) != -1) {
+	pidfile = user = NULL;
+	while ((ch = getopt(argc, argv, "-cf:p:u:")) != -1) {
 		switch (ch) {
 		case 'c':
 			nochdir = 0;
@@ -63,15 +63,12 @@ main(int argc, char *argv[])
 		case 'f':
 			noclose = 0;
 			break;
-		case 'u':
-			user = optarg;
-			break;
-		case 'g':
-			group = optarg;
-			break;
 		case 'p':
 			pidfile = optarg;
 			break;
+		case 'u':
+			user = optarg;
+			break;
 		default:
 			usage();
 		}
@@ -82,12 +79,8 @@ main(int argc, char *argv[])
 	if (argc == 0)
 		usage();
 
-	if (user || group) {
-		if (getuid() != 0)
-			errx(1, "only root user is allowed to chroot "
-			    "and change UID/GID");
-		restrict_process(user, group);
-	}
+	if (user != NULL)
+		restrict_process(user);
 
 	/*
 	 * Try to open the pidfile before calling daemon(3),
@@ -126,34 +119,23 @@ main(int argc, char *argv[])
 }
 
 static void
-restrict_process(const char *user, const char *group)
+restrict_process(const char *user)
 {
-	struct group *gr = NULL;
 	struct passwd *pw = NULL;
-	errno = 0;
 
-	if (group != NULL) {
-		if (initgroups(user, gr->gr_gid) == -1)
-			errx(1, "User not in group list");
-		if ((gr = getgrnam(group)) == NULL)
-			errx(1, "Group %s does not exist", group);
-		if (setgid(gr->gr_gid) == -1)
-			err(1, "%s", group);
-	}
+	pw = getpwnam(user);
+	if (pw == NULL)
+		errx(1, "unknown user: %s", user);
 
-	if (user != NULL) {
-		if ((pw = getpwnam(user)) == NULL)
-			errx(1, "User %s does not exist", user);
-		if (setuid(pw->pw_uid) == -1)
-			err(1, "%s", user);
-	}
+	if (setusercontext(NULL, pw, pw->pw_uid, LOGIN_SETALL) != 0)
+		errx(1, "failed to set user environment");
 }
 
 static void
 usage(void)
 {
 	(void)fprintf(stderr,
-	    "usage: daemon [-cf] [-g group] [-p pidfile] [-u user] command "
+	    "usage: daemon [-cf] [-p pidfile] [-u user] command "
 		"arguments ...\n");
 	exit(1);
 }