freebsd-dev/usr.sbin/jexec/jexec.c
Jamie Gritton 3bbdb8a755 Run a shell in the jail when no command is specified.
Add a new flag, -l, for a clean environment, same as jail(8) exec.clean.
Change the GET_USER_INFO macro into a function.

PR:		201300
Submitted by:	Willem Jan Withagen
MFC after:	3 days
2015-07-12 17:03:50 +00:00

192 lines
4.8 KiB
C

/*-
* Copyright (c) 2003 Mike Barcroft <mike@FreeBSD.org>
* Copyright (c) 2008 Bjoern A. Zeeb <bz@FreeBSD.org>
* 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.
*
* 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.
*
* $FreeBSD$
*/
#include <sys/param.h>
#include <sys/jail.h>
#include <sys/socket.h>
#include <sys/sysctl.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <err.h>
#include <errno.h>
#include <jail.h>
#include <limits.h>
#include <login_cap.h>
#include <paths.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
extern char **environ;
static void get_user_info(const char *username, const struct passwd **pwdp,
login_cap_t **lcapp);
static void usage(void);
int
main(int argc, char *argv[])
{
int jid;
login_cap_t *lcap = NULL;
int ch, clean, uflag, Uflag;
char *cleanenv;
const struct passwd *pwd = NULL;
const char *username, *shell, *term;
ch = clean = uflag = Uflag = 0;
username = NULL;
while ((ch = getopt(argc, argv, "lnu:U:")) != -1) {
switch (ch) {
case 'l':
clean = 1;
break;
case 'n':
/* Specified name, now unused */
break;
case 'u':
username = optarg;
uflag = 1;
break;
case 'U':
username = optarg;
Uflag = 1;
break;
default:
usage();
}
}
argc -= optind;
argv += optind;
if (argc < 1)
usage();
if (uflag && Uflag)
usage();
if (uflag || (clean && !Uflag))
/* User info from the home environment */
get_user_info(username, &pwd, &lcap);
/* Attach to the jail */
jid = jail_getid(argv[0]);
if (jid < 0)
errx(1, "%s", jail_errmsg);
if (jail_attach(jid) == -1)
err(1, "jail_attach(%d)", jid);
if (chdir("/") == -1)
err(1, "chdir(): /");
/* Set up user environment */
if (clean || username != NULL) {
if (Uflag)
/* User info from the jail environment */
get_user_info(username, &pwd, &lcap);
if (clean) {
term = getenv("TERM");
cleanenv = NULL;
environ = &cleanenv;
setenv("PATH", "/bin:/usr/bin", 1);
if (term != NULL)
setenv("TERM", term, 1);
}
if (setgid(pwd->pw_gid) != 0)
err(1, "setgid");
if (setusercontext(lcap, pwd, pwd->pw_uid, username
? LOGIN_SETALL & ~LOGIN_SETGROUP & ~LOGIN_SETLOGIN
: LOGIN_SETPATH | LOGIN_SETENV) != 0)
err(1, "setusercontext");
login_close(lcap);
setenv("USER", pwd->pw_name, 1);
setenv("HOME", pwd->pw_dir, 1);
setenv("SHELL",
*pwd->pw_shell ? pwd->pw_shell : _PATH_BSHELL, 1);
if (clean && chdir(pwd->pw_dir) < 0)
err(1, "chdir: %s", pwd->pw_dir);
endpwent();
}
/* Run the specified command, or the shell */
if (argc > 1) {
if (execvp(argv[1], argv + 1) < 0)
err(1, "execvp: %s", argv[1]);
} else {
if (!(shell = getenv("SHELL")))
shell = _PATH_BSHELL;
if (execlp(shell, shell, "-i", NULL) < 0)
err(1, "execlp: %s", shell);
}
exit(0);
}
static void
get_user_info(const char *username, const struct passwd **pwdp,
login_cap_t **lcapp)
{
uid_t uid;
const struct passwd *pwd;
errno = 0;
if (username) {
pwd = getpwnam(username);
if (pwd == NULL) {
if (errno)
err(1, "getpwnam: %s", username);
else
errx(1, "%s: no such user", username);
}
} else {
uid = getuid();
pwd = getpwuid(uid);
if (pwd == NULL) {
if (errno)
err(1, "getpwuid: %d", uid);
else
errx(1, "unknown uid: %d", uid);
}
}
*pwdp = pwd;
*lcapp = login_getpwclass(pwd);
if (*lcapp == NULL)
err(1, "getpwclass: %s", pwd->pw_name);
if (initgroups(pwd->pw_name, pwd->pw_gid) < 0)
err(1, "initgroups: %s", pwd->pw_name);
}
static void
usage(void)
{
fprintf(stderr, "%s\n",
"usage: jexec [-l] [-u username | -U username] jail [command ...]");
exit(1);
}