xref: /illumos-gate/usr/src/cmd/newgrp/newgrp.c (revision 16cac786)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
28 /*	  All Rights Reserved  	*/
29 
30 #pragma ident	"%Z%%M%	%I%	%E% SMI"
31 
32 /*
33  * newgrp [-l | -] [group]
34  *
35  * rules
36  *	if no arg, group id in password file is used
37  *	else if group id == id in password file
38  *	else if login name is in member list
39  *	else if password is present and user knows it
40  *	else too bad
41  */
42 #include <stdio.h>
43 #include <sys/types.h>
44 #include <pwd.h>
45 #include <grp.h>
46 #include <crypt.h>
47 #include <string.h>
48 #include <stdlib.h>
49 #include <locale.h>
50 #include <syslog.h>
51 #include <unistd.h>
52 
53 #include <bsm/adt_event.h>
54 
55 #define	SHELL	"/usr/bin/sh"
56 
57 #define	PATH	"PATH=:/usr/bin:"
58 #define	SUPATH	"PATH=:/usr/sbin:/usr/bin"
59 #define	ELIM	128
60 
61 char	PW[] = "newgrp: Password: ";
62 char	NG[] = "newgrp: Sorry";
63 char	PD[] = "newgrp: Permission denied";
64 char	UG[] = "newgrp: Unknown group";
65 char	NS[] = "newgrp: You have no shell";
66 
67 char *homedir;
68 char *logname;
69 
70 char *envinit[ELIM];
71 extern char **environ;
72 char *path = PATH;
73 char *supath = SUPATH;
74 
75 void error(char *s) __NORETURN;
76 void warn(char *s);
77 void usage(void);
78 
79 int
80 main(int argc, char *argv[])
81 {
82 	struct passwd *p;
83 	gid_t chkgrp();
84 	int eflag = 0;
85 	int flag;
86 	uid_t uid;
87 	char *shell, *dir, *name;
88 	size_t len;
89 
90 #ifdef	DEBUG
91 	chroot(".");
92 #endif
93 
94 	(void) setlocale(LC_ALL, "");
95 #if !defined(TEXT_DOMAIN)		/* Should be defined by cc -D */
96 #define	TEXT_DOMAIN	"SYS_TEST"	/* Use this only if it weren't */
97 #endif
98 	(void) textdomain(TEXT_DOMAIN);
99 
100 	if ((p = getpwuid(getuid())) == NULL)
101 		error(NG);
102 	endpwent();
103 
104 	while ((flag = getopt(argc, argv, "l")) != EOF) {
105 		switch (flag) {
106 		case 'l':
107 			eflag++;
108 			break;
109 
110 		default:
111 			usage();
112 			break;
113 		}
114 	}
115 
116 	argc -= optind;
117 	argv = &argv[optind];
118 
119 	if (argc > 0 && *argv[0] == '-') {
120 		if (eflag)
121 			usage();
122 		eflag++;
123 		argv++;
124 		--argc;
125 	}
126 
127 	if (argc > 0)
128 		p->pw_gid = chkgrp(argv[0], p);
129 
130 	uid = p->pw_uid;
131 
132 	len = strlen(p->pw_dir) + 1;
133 	if ((dir = (char *)malloc(len)) == NULL)
134 		error("newgrp: Memory request failed");
135 	(void) strncpy(dir, p->pw_dir, len);
136 	len = strlen(p->pw_name) + 1;
137 	if ((name = (char *)malloc(len)) == NULL)
138 		error("newgrp: Memory request failed");
139 	(void) strncpy(name, p->pw_name, len);
140 
141 	if (setgid(p->pw_gid) < 0 || setuid(getuid()) < 0)
142 		error(NG);
143 
144 	if (!*p->pw_shell) {
145 		if ((shell = getenv("SHELL")) != NULL) {
146 			p->pw_shell = shell;
147 		} else {
148 			p->pw_shell = SHELL;
149 		}
150 	}
151 
152 	if (eflag) {
153 		char *simple;
154 
155 		len = strlen(dir) + 6;
156 		if ((homedir = (char *)malloc(len)) == NULL)
157 			error("newgrp: Memory request failed");
158 		(void) snprintf(homedir, len, "HOME=%s", dir);
159 		len = strlen(name) + 9;
160 		if ((logname = (char *)malloc(len)) == NULL)
161 			error("newgrp: Memory request failed");
162 		(void) snprintf(logname, len, "LOGNAME=%s", name);
163 
164 
165 		envinit[2] = logname;
166 		(void) chdir(dir);
167 		envinit[0] = homedir;
168 		if (uid == 0)
169 			envinit[1] = supath;
170 		else
171 			envinit[1] = path;
172 		envinit[3] = NULL;
173 		environ = envinit;
174 
175 		len = strlen(p->pw_shell) + 2;
176 		if ((shell = (char *)malloc(len)) == NULL)
177 			error("newgrp: Memory request failed");
178 		(void) snprintf(shell, len, "-%s", p->pw_shell);
179 		simple = strrchr(shell, '/');
180 		if (simple) {
181 			*(shell+1) = '\0';
182 			shell = strcat(shell, ++simple);
183 		}
184 	}
185 	else
186 		shell = p->pw_shell;
187 
188 	(void) execl(p->pw_shell, shell, NULL);
189 	warn(NS);
190 	return (1);
191 }
192 
193 void
194 warn(char *s)
195 {
196 	(void) fprintf(stderr, "%s\n", gettext(s));
197 }
198 
199 void
200 error(char *s)
201 {
202 	warn(s);
203 	exit(1);
204 }
205 
206 void
207 put_event(char *gname, int sorf)
208 {
209 	adt_session_data_t	*ah;
210 	adt_event_data_t	*event;
211 
212 	if (adt_start_session(&ah, NULL, ADT_USE_PROC_DATA) != 0) {
213 		syslog(LOG_AUTH | LOG_ALERT,
214 		    "adt_start_session(ADT_newgrp_login): %m");
215 	}
216 	if ((event = adt_alloc_event(ah, ADT_newgrp_login)) == NULL) {
217 		syslog(LOG_AUTH | LOG_ALERT,
218 		    "adt_alloc_event(ADT_newgrp_login): %m");
219 	} else {
220 		event->adt_newgrp_login.groupname = gname;
221 	}
222 
223 	if (adt_put_event(event, sorf, sorf) != 0) {
224 		syslog(LOG_AUTH | LOG_ALERT,
225 		    "adt_put_event(ADT_newgrp, %d): %m", sorf);
226 	}
227 	adt_free_event(event);
228 	(void) adt_end_session(ah);
229 }
230 
231 gid_t
232 chkgrp(gname, p)
233 char	*gname;
234 struct	passwd *p;
235 {
236 	char **t;
237 	struct group *g;
238 
239 	g = getgrnam(gname);
240 	endgrent();
241 	if (g == NULL) {
242 		warn(UG);
243 		put_event(gname, ADT_FAILURE);
244 		return (getgid());
245 	}
246 	if (p->pw_gid == g->gr_gid || getuid() == 0) {
247 		put_event(gname, ADT_SUCCESS);
248 		return (g->gr_gid);
249 	}
250 	for (t = g->gr_mem; *t; ++t) {
251 		if (strcmp(p->pw_name, *t) == 0) {
252 			put_event(gname, ADT_SUCCESS);
253 			return (g->gr_gid);
254 		}
255 	}
256 	if (*g->gr_passwd) {
257 		if (!isatty(fileno(stdin))) {
258 			put_event(gname, ADT_FAILURE);
259 			error(PD);
260 		}
261 		if (strcmp(g->gr_passwd,
262 		    crypt(getpassphrase(PW), g->gr_passwd)) == 0) {
263 			put_event(gname, ADT_SUCCESS);
264 			return (g->gr_gid);
265 		}
266 	}
267 	put_event(gname, ADT_FAILURE);
268 	warn(NG);
269 	return (getgid());
270 }
271 
272 void
273 usage(void)
274 {
275 	(void) fprintf(stderr, gettext(
276 		"usage: newgrp [-l | -] [group]\n"));
277 	exit(2);
278 }
279