diff options
Diffstat (limited to 'bin/su/su.c')
| -rw-r--r-- | bin/su/su.c | 188 |
1 files changed, 188 insertions, 0 deletions
diff --git a/bin/su/su.c b/bin/su/su.c new file mode 100644 index 0000000..4c7d0eb --- /dev/null +++ b/bin/su/su.c @@ -0,0 +1,188 @@ +/*- + * Copyright (c) 2002-2003 Networks Associates Technology, Inc. + * Copyright (c) 2004-2007 Dag-Erling Smørgrav + * All rights reserved. + * + * This software was developed for the FreeBSD Project by ThinkSec AS and + * Network Associates Laboratories, the Security Research Division of + * Network Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 + * ("CBOSS"), as part of the DARPA CHATS research program. + * + * 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. The name of the author may not be used to endorse or promote + * products derived from this software without specific prior written + * permission. + * + * 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. + * + * $Id: su.c 408 2007-12-21 11:36:24Z des $ + */ + +#include <sys/param.h> +#include <sys/wait.h> + +#include <err.h> +#include <grp.h> +#include <pwd.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <syslog.h> +#include <unistd.h> + +#include <security/pam_appl.h> +#include <security/openpam.h> /* for openpam_ttyconv() */ + +extern char **environ; + +static pam_handle_t *pamh; +static struct pam_conv pamc; + +static void +usage(void) +{ + + fprintf(stderr, "Usage: su [login [args]]\n"); + exit(1); +} + +int +main(int argc, char *argv[]) +{ + char hostname[MAXHOSTNAMELEN]; + const char *user, *tty; + const void *item; + char **args, **pam_envlist, **pam_env; + struct passwd *pwd; + int o, pam_err, status; + pid_t pid; + + while ((o = getopt(argc, argv, "h")) != -1) + switch (o) { + case 'h': + default: + usage(); + } + + argc -= optind; + argv += optind; + + if (argc > 0) { + user = *argv; + --argc; + ++argv; + } else { + user = "root"; + } + + /* initialize PAM */ + pamc.conv = &openpam_ttyconv; + pam_start("su", user, &pamc, &pamh); + + /* set some items */ + gethostname(hostname, sizeof(hostname)); + if ((pam_err = pam_set_item(pamh, PAM_RHOST, hostname)) != PAM_SUCCESS) + goto pamerr; + user = getlogin(); + if ((pam_err = pam_set_item(pamh, PAM_RUSER, user)) != PAM_SUCCESS) + goto pamerr; + tty = ttyname(STDERR_FILENO); + if ((pam_err = pam_set_item(pamh, PAM_TTY, tty)) != PAM_SUCCESS) + goto pamerr; + + /* authenticate the applicant */ + if ((pam_err = pam_authenticate(pamh, 0)) != PAM_SUCCESS) + goto pamerr; + if ((pam_err = pam_acct_mgmt(pamh, 0)) == PAM_NEW_AUTHTOK_REQD) + pam_err = pam_chauthtok(pamh, PAM_CHANGE_EXPIRED_AUTHTOK); + if (pam_err != PAM_SUCCESS) + goto pamerr; + + /* establish the requested credentials */ + if ((pam_err = pam_setcred(pamh, PAM_ESTABLISH_CRED)) != PAM_SUCCESS) + goto pamerr; + + /* authentication succeeded; open a session */ + if ((pam_err = pam_open_session(pamh, 0)) != PAM_SUCCESS) + goto pamerr; + + /* get mapped user name; PAM may have changed it */ + pam_err = pam_get_item(pamh, PAM_USER, &item); + if (pam_err != PAM_SUCCESS || (pwd = getpwnam(user = item)) == NULL) + goto pamerr; + + /* export PAM environment */ + if ((pam_envlist = pam_getenvlist(pamh)) != NULL) { + for (pam_env = pam_envlist; *pam_env != NULL; ++pam_env) { + putenv(*pam_env); + free(*pam_env); + } + free(pam_envlist); + } + + /* build argument list */ + if ((args = calloc(argc + 2, sizeof *args)) == NULL) { + warn("calloc()"); + goto err; + } + *args = pwd->pw_shell; + memcpy(args + 1, argv, argc * sizeof *args); + + /* fork and exec */ + switch ((pid = fork())) { + case -1: + warn("fork()"); + goto err; + case 0: + /* child: give up privs and start a shell */ + + /* set uid and groups */ + if (initgroups(pwd->pw_name, pwd->pw_gid) == -1) { + warn("initgroups()"); + _exit(1); + } + if (setgid(pwd->pw_gid) == -1) { + warn("setgid()"); + _exit(1); + } + if (setuid(pwd->pw_uid) == -1) { + warn("setuid()"); + _exit(1); + } + execve(*args, args, environ); + warn("execve()"); + _exit(1); + default: + /* parent: wait for child to exit */ + waitpid(pid, &status, 0); + + /* close the session and release PAM resources */ + pam_err = pam_close_session(pamh, 0); + pam_end(pamh, pam_err); + + exit(WEXITSTATUS(status)); + } + +pamerr: + fprintf(stderr, "Sorry\n"); +err: + pam_end(pamh, pam_err); + exit(1); +} |
