2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Copyright (c) 2002 Tim J. Robbins.
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * newgrp -- change to a new group
33 #include <sys/cdefs.h>
34 __FBSDID("$FreeBSD$");
36 #include <sys/types.h>
42 #include <login_cap.h>
50 static void addgroup(const char *grpname);
51 static void doshell(void);
52 static int inarray(gid_t, const gid_t[], int);
53 static void loginshell(void);
54 static void restoregrps(void);
55 static void usage(void);
57 static struct passwd *pwd;
60 extern char **environ;
62 /* Manipulate effective user ID. */
63 #define PRIV_START do { \
64 if (seteuid(euid) < 0) \
67 #define PRIV_END do { \
68 if (seteuid(getuid()) < 0) \
73 main(int argc, char *argv[])
77 if ((euid = geteuid()) != 0)
78 warnx("need root permissions to function properly, check setuid bit");
79 if (seteuid(getuid()) < 0)
82 if ((pwd = getpwuid(getuid())) == NULL)
83 errx(1, "unknown user");
86 while ((ch = getopt(argc, argv, "-l")) != -1) {
88 case '-': /* Obsolescent */
110 if (seteuid(euid) < 0)
112 if (setuid(getuid()) < 0)
128 fprintf(stderr, "usage: newgrp [-l] [group]\n");
138 initres = initgroups(pwd->pw_name, pwd->pw_gid);
139 setres = setgid(pwd->pw_gid);
149 addgroup(const char *grpname)
152 long lgid, ngrps_max;
153 int dbmember, i, ngrps;
156 char *ep, *pass, *cryptpw;
161 /* Try it as a group name, then a group id. */
162 if ((grp = getgrnam(grpname)) == NULL)
163 if ((lgid = strtol(grpname, &ep, 10)) <= 0 || *ep != '\0' ||
164 (grp = getgrgid((gid_t)lgid)) == NULL ) {
165 warnx("%s: bad group name", grpname);
170 * If the user is not a member of the requested group and the group
171 * has a password, prompt and check it.
174 if (pwd->pw_gid == grp->gr_gid)
176 for (p = grp->gr_mem; *p != NULL; p++)
177 if (strcmp(*p, pwd->pw_name) == 0) {
181 if (!dbmember && *grp->gr_passwd != '\0' && getuid() != 0) {
182 pass = getpass("Password:");
185 cryptpw = crypt(pass, grp->gr_passwd);
186 if (cryptpw == NULL || strcmp(grp->gr_passwd, cryptpw) != 0) {
187 fprintf(stderr, "Sorry\n");
192 ngrps_max = sysconf(_SC_NGROUPS_MAX) + 1;
193 if ((grps = malloc(sizeof(gid_t) * ngrps_max)) == NULL)
195 if ((ngrps = getgroups(ngrps_max, (gid_t *)grps)) < 0) {
200 /* Remove requested gid from supp. list if it exists. */
201 if (grp->gr_gid != egid && inarray(grp->gr_gid, grps, ngrps)) {
202 for (i = 0; i < ngrps; i++)
203 if (grps[i] == grp->gr_gid)
206 memmove(&grps[i], &grps[i + 1], (ngrps - i) * sizeof(gid_t));
208 if (setgroups(ngrps, (const gid_t *)grps) < 0) {
217 if (setgid(grp->gr_gid)) {
223 grps[0] = grp->gr_gid;
225 /* Add old effective gid to supp. list if it does not exist. */
226 if (egid != grp->gr_gid && !inarray(egid, grps, ngrps)) {
227 if (ngrps == ngrps_max)
228 warnx("too many groups");
230 grps[ngrps++] = egid;
232 if (setgroups(ngrps, (const gid_t *)grps)) {
245 inarray(gid_t gid, const gid_t grps[], int ngrps)
249 for (i = 0; i < ngrps; i++)
256 * Set the environment to what would be expected if the user logged in
257 * again; this performs the same steps as su(1)'s -l option.
262 char *args[2], **cleanenv, *term, *ticket;
266 shell = pwd->pw_shell;
268 shell = _PATH_BSHELL;
269 if (chdir(pwd->pw_dir) < 0) {
270 warn("%s", pwd->pw_dir);
274 term = getenv("TERM");
275 ticket = getenv("KRBTKFILE");
277 if ((cleanenv = calloc(20, sizeof(char *))) == NULL)
282 lc = login_getpwclass(pwd);
283 setusercontext(lc, pwd, pwd->pw_uid,
284 LOGIN_SETPATH|LOGIN_SETUMASK|LOGIN_SETENV);
286 setenv("USER", pwd->pw_name, 1);
287 setenv("SHELL", shell, 1);
288 setenv("HOME", pwd->pw_dir, 1);
290 setenv("TERM", term, 1);
292 setenv("KRBTKFILE", ticket, 1);
294 if (asprintf(args, "-%s", shell) < 0)
307 shell = pwd->pw_shell;
309 shell = _PATH_BSHELL;
310 execl(shell, shell, (char *)NULL);