2 * Copyright (c) 2002 Tim J. Robbins.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * $FreeBSD: /src/usr.bin/newgrp/newgrp.c,v 1.2 2003/10/30 15:14:34 harti Exp $
27 * $DragonFly: src/usr.bin/newgrp/newgrp.c,v 1.3 2004/12/08 22:26:42 liamfoy Exp $
31 * newgrp -- change to a new group
34 #include <sys/types.h>
41 #include <login_cap.h>
49 static void addgroup(const char *grpname);
50 static void doshell(void);
51 static int inarray(gid_t, const gid_t[], int);
52 static void loginshell(void);
53 static void restoregrps(void);
54 static void usage(void);
56 static struct passwd *pwd;
59 extern char **environ;
61 /* Manipulate effective user ID. */
62 #define PRIV_START do { \
63 if (seteuid(euid) < 0) \
66 #define PRIV_END do { \
67 if (seteuid(getuid()) < 0) \
72 main(int argc, char *argv[])
76 if ((euid = geteuid()) != 0)
77 warnx("need root permissions to function properly, check setuid bit");
78 if (seteuid(getuid()) < 0)
81 if ((pwd = getpwuid(getuid())) == NULL)
82 errx(1, "unknown user");
85 while ((ch = getopt(argc, argv, "-l")) != -1) {
87 case '-': /* Obsolescent */
109 if (seteuid(euid) < 0)
111 if (setuid(getuid()) < 0)
127 fprintf(stderr, "usage: newgrp [-l] [group]\n");
137 initres = initgroups(pwd->pw_name, pwd->pw_gid);
138 setres = setgid(pwd->pw_gid);
148 addgroup(const char *grpname)
150 gid_t grps[NGROUPS_MAX];
152 int dbmember, i, ngrps;
155 char *ep, *pass, *cryptpw;
160 /* Try it as a group name, then a group id. */
161 if ((grp = getgrnam(grpname)) == NULL)
162 if ((lgid = strtol(grpname, &ep, 10)) <= 0 || *ep != '\0' ||
163 (grp = getgrgid((gid_t)lgid)) == NULL ) {
164 warnx("%s: bad group name", grpname);
169 * If the user is not a member of the requested group and the group
170 * has a password, prompt and check it.
173 if (pwd->pw_gid == grp->gr_gid)
175 for (p = grp->gr_mem; *p != NULL; p++)
176 if (strcmp(*p, pwd->pw_name) == 0) {
180 if (!dbmember && *grp->gr_passwd != '\0' && getuid() != 0) {
181 pass = getpass("Password:");
184 cryptpw = crypt(pass, grp->gr_passwd);
185 if (cryptpw == NULL || strcmp(grp->gr_passwd, cryptpw) != 0) {
186 fprintf(stderr, "Sorry\n");
191 if ((ngrps = getgroups(NGROUPS_MAX, (gid_t *)grps)) < 0) {
196 /* Remove requested gid from supp. list if it exists. */
197 if (grp->gr_gid != egid && inarray(grp->gr_gid, grps, ngrps)) {
198 for (i = 0; i < ngrps; i++)
199 if (grps[i] == grp->gr_gid)
202 memmove(&grps[i], &grps[i + 1], (ngrps - i) * sizeof(gid_t));
204 if (setgroups(ngrps, (const gid_t *)grps) < 0) {
213 if (setgid(grp->gr_gid)) {
219 grps[0] = grp->gr_gid;
221 /* Add old effective gid to supp. list if it does not exist. */
222 if (egid != grp->gr_gid && !inarray(egid, grps, ngrps)) {
223 if (ngrps == NGROUPS_MAX)
224 warnx("too many groups");
226 grps[ngrps++] = egid;
228 if (setgroups(ngrps, (const gid_t *)grps)) {
240 inarray(gid_t gid, const gid_t grps[], int ngrps)
244 for (i = 0; i < ngrps; i++)
251 * Set the environment to what would be expected if the user logged in
252 * again; this performs the same steps as su(1)'s -l option.
257 char *args[2], **cleanenv, *term, *ticket;
261 shell = pwd->pw_shell;
263 shell = _PATH_BSHELL;
264 if (chdir(pwd->pw_dir) < 0) {
265 warn("%s", pwd->pw_dir);
269 term = getenv("TERM");
270 ticket = getenv("KRBTKFILE");
272 if ((cleanenv = calloc(20, sizeof(char *))) == NULL)
277 lc = login_getpwclass(pwd);
278 setusercontext(lc, pwd, pwd->pw_uid,
279 LOGIN_SETPATH|LOGIN_SETUMASK|LOGIN_SETENV);
281 if (setenv("USER", pwd->pw_name, 1) == -1)
282 err(EXIT_FAILURE, "setenv failed");
284 if (setenv("SHELL", shell, 1) == -1)
285 err(EXIT_FAILURE, "setenv failed");
287 if (setenv("HOME", pwd->pw_dir, 1) == -1)
288 err(EXIT_FAILURE, "setenv failed");
291 if (setenv("TERM", term, 1) == -1)
292 err(EXIT_FAILURE, "setenv failed");
294 if (setenv("KRBTKFILE", ticket, 1) == -1)
295 err(EXIT_FAILURE, "setenv failed");
297 if (asprintf(args, "-%s", basename(shell)) < 0)
310 shell = pwd->pw_shell;
312 shell = _PATH_BSHELL;
313 execl(shell, basename(shell), NULL);