xref: /illumos-gate/usr/src/cmd/newgrp/newgrp.c (revision ddb365bfc9e868ad24ccdcb0dc91af18b10df082)
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 /*
31  * newgrp [-l | -] [group]
32  *
33  * rules
34  *	if no arg, group id in password file is used
35  *	else if group id == id in password file
36  *	else if login name is in member list
37  *	else if password is present and user knows it
38  *	else too bad
39  */
40 #include <stdio.h>
41 #include <sys/types.h>
42 #include <pwd.h>
43 #include <grp.h>
44 #include <crypt.h>
45 #include <string.h>
46 #include <stdlib.h>
47 #include <locale.h>
48 #include <syslog.h>
49 #include <unistd.h>
50 
51 #include <bsm/adt_event.h>
52 
53 #define	SHELL	"/usr/bin/sh"
54 
55 #define	PATH	"PATH=:/usr/bin:"
56 #define	SUPATH	"PATH=:/usr/sbin:/usr/bin"
57 #define	ELIM	128
58 
59 char	PW[] = "newgrp: Password: ";
60 char	NG[] = "newgrp: Sorry";
61 char	PD[] = "newgrp: Permission denied";
62 char	UG[] = "newgrp: Unknown group";
63 char	NS[] = "newgrp: You have no shell";
64 
65 char *homedir;
66 char *logname;
67 
68 char *envinit[ELIM];
69 extern char **environ;
70 char *path = PATH;
71 char *supath = SUPATH;
72 
73 void error(char *s) __NORETURN;
74 static void warn(char *s);
75 void usage(void);
76 
77 int
78 main(int argc, char *argv[])
79 {
80 	struct passwd *p;
81 	gid_t chkgrp();
82 	int eflag = 0;
83 	int flag;
84 	uid_t uid;
85 	char *shell, *dir, *name;
86 	size_t len;
87 
88 #ifdef	DEBUG
89 	chroot(".");
90 #endif
91 
92 	(void) setlocale(LC_ALL, "");
93 #if !defined(TEXT_DOMAIN)		/* Should be defined by cc -D */
94 #define	TEXT_DOMAIN	"SYS_TEST"	/* Use this only if it weren't */
95 #endif
96 	(void) textdomain(TEXT_DOMAIN);
97 
98 	if ((p = getpwuid(getuid())) == NULL)
99 		error(NG);
100 	endpwent();
101 
102 	while ((flag = getopt(argc, argv, "l")) != EOF) {
103 		switch (flag) {
104 		case 'l':
105 			eflag++;
106 			break;
107 
108 		default:
109 			usage();
110 			break;
111 		}
112 	}
113 
114 	argc -= optind;
115 	argv = &argv[optind];
116 
117 	if (argc > 0 && *argv[0] == '-') {
118 		if (eflag)
119 			usage();
120 		eflag++;
121 		argv++;
122 		--argc;
123 	}
124 
125 	if (argc > 0)
126 		p->pw_gid = chkgrp(argv[0], p);
127 
128 	uid = p->pw_uid;
129 
130 	len = strlen(p->pw_dir) + 1;
131 	if ((dir = (char *)malloc(len)) == NULL)
132 		error("newgrp: Memory request failed");
133 	(void) strncpy(dir, p->pw_dir, len);
134 	len = strlen(p->pw_name) + 1;
135 	if ((name = (char *)malloc(len)) == NULL)
136 		error("newgrp: Memory request failed");
137 	(void) strncpy(name, p->pw_name, len);
138 
139 	if (setgid(p->pw_gid) < 0 || setuid(getuid()) < 0)
140 		error(NG);
141 
142 	if (!*p->pw_shell) {
143 		if ((shell = getenv("SHELL")) != NULL) {
144 			p->pw_shell = shell;
145 		} else {
146 			p->pw_shell = SHELL;
147 		}
148 	}
149 
150 	if (eflag) {
151 		char *simple;
152 
153 		len = strlen(dir) + 6;
154 		if ((homedir = (char *)malloc(len)) == NULL)
155 			error("newgrp: Memory request failed");
156 		(void) snprintf(homedir, len, "HOME=%s", dir);
157 		len = strlen(name) + 9;
158 		if ((logname = (char *)malloc(len)) == NULL)
159 			error("newgrp: Memory request failed");
160 		(void) snprintf(logname, len, "LOGNAME=%s", name);
161 
162 
163 		envinit[2] = logname;
164 		(void) chdir(dir);
165 		envinit[0] = homedir;
166 		if (uid == 0)
167 			envinit[1] = supath;
168 		else
169 			envinit[1] = path;
170 		envinit[3] = NULL;
171 		environ = envinit;
172 
173 		len = strlen(p->pw_shell) + 2;
174 		if ((shell = (char *)malloc(len)) == NULL)
175 			error("newgrp: Memory request failed");
176 		(void) snprintf(shell, len, "-%s", p->pw_shell);
177 		simple = strrchr(shell, '/');
178 		if (simple) {
179 			*(shell+1) = '\0';
180 			shell = strcat(shell, ++simple);
181 		}
182 	}
183 	else
184 		shell = p->pw_shell;
185 
186 	(void) execl(p->pw_shell, shell, NULL);
187 	warn(NS);
188 	return (1);
189 }
190 
191 static void
192 warn(char *s)
193 {
194 	(void) fprintf(stderr, "%s\n", gettext(s));
195 }
196 
197 void
198 error(char *s)
199 {
200 	warn(s);
201 	exit(1);
202 }
203 
204 void
205 put_event(char *gname, int sorf)
206 {
207 	adt_session_data_t	*ah;
208 	adt_event_data_t	*event;
209 
210 	if (adt_start_session(&ah, NULL, ADT_USE_PROC_DATA) != 0) {
211 		syslog(LOG_AUTH | LOG_ALERT,
212 		    "adt_start_session(ADT_newgrp_login): %m");
213 	}
214 	if ((event = adt_alloc_event(ah, ADT_newgrp_login)) == NULL) {
215 		syslog(LOG_AUTH | LOG_ALERT,
216 		    "adt_alloc_event(ADT_newgrp_login): %m");
217 	} else {
218 		event->adt_newgrp_login.groupname = gname;
219 	}
220 
221 	if (adt_put_event(event, sorf, sorf) != 0) {
222 		syslog(LOG_AUTH | LOG_ALERT,
223 		    "adt_put_event(ADT_newgrp, %d): %m", sorf);
224 	}
225 	adt_free_event(event);
226 	(void) adt_end_session(ah);
227 }
228 
229 gid_t
230 chkgrp(gname, p)
231 char	*gname;
232 struct	passwd *p;
233 {
234 	char **t;
235 	struct group *g;
236 
237 	g = getgrnam(gname);
238 	endgrent();
239 	if (g == NULL) {
240 		warn(UG);
241 		put_event(gname, ADT_FAILURE);
242 		return (getgid());
243 	}
244 	if (p->pw_gid == g->gr_gid || getuid() == 0) {
245 		put_event(gname, ADT_SUCCESS);
246 		return (g->gr_gid);
247 	}
248 	for (t = g->gr_mem; *t; ++t) {
249 		if (strcmp(p->pw_name, *t) == 0) {
250 			put_event(gname, ADT_SUCCESS);
251 			return (g->gr_gid);
252 		}
253 	}
254 	if (*g->gr_passwd) {
255 		if (!isatty(fileno(stdin))) {
256 			put_event(gname, ADT_FAILURE);
257 			error(PD);
258 		}
259 		if (strcmp(g->gr_passwd,
260 		    crypt(getpassphrase(PW), g->gr_passwd)) == 0) {
261 			put_event(gname, ADT_SUCCESS);
262 			return (g->gr_gid);
263 		}
264 	}
265 	put_event(gname, ADT_FAILURE);
266 	warn(NG);
267 	return (getgid());
268 }
269 
270 void
271 usage(void)
272 {
273 	(void) fprintf(stderr, gettext(
274 	    "usage: newgrp [-l | -] [group]\n"));
275 	exit(2);
276 }
277