1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1990, 1993, 1994
5 * The Regents of the University of California. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
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.
15 * 3. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32 /*
33 * This module is used to "verify" password entries by chpass(1) and
34 * pwd_mkdb(8).
35 */
36
37 #include <sys/param.h>
38
39 #include <err.h>
40 #include <errno.h>
41 #include <pwd.h>
42 #include <string.h>
43 #include <stdlib.h>
44 #include <unistd.h>
45
46 #include "pw_scan.h"
47
48 /*
49 * Some software assumes that IDs are short. We should emit warnings
50 * for id's which cannot be stored in a short, but we are more liberal
51 * by default, warning for IDs greater than USHRT_MAX.
52 *
53 * If pw_big_ids_warning is -1 on entry to pw_scan(), it will be set based
54 * on the existence of PW_SCAN_BIG_IDS in the environment.
55 *
56 * It is believed all baseline system software that can not handle the
57 * normal ID sizes is now gone so pw_big_ids_warning is disabled for now.
58 * But the code has been left in place in case end-users want to re-enable
59 * it and/or for the next time the ID sizes get bigger but pieces of the
60 * system lag behind.
61 */
62 static int pw_big_ids_warning = 0;
63
64 void
__pw_initpwd(struct passwd * pwd)65 __pw_initpwd(struct passwd *pwd)
66 {
67 static char nul[] = "";
68
69 memset(pwd, 0, sizeof(*pwd));
70 pwd->pw_uid = (uid_t)-1; /* Considered least likely to lead to */
71 pwd->pw_gid = (gid_t)-1; /* a security issue. */
72 pwd->pw_name = nul;
73 pwd->pw_passwd = nul;
74 pwd->pw_class = nul;
75 pwd->pw_gecos = nul;
76 pwd->pw_dir = nul;
77 pwd->pw_shell = nul;
78 }
79
80 int
__pw_scan(char * bp,struct passwd * pw,int flags)81 __pw_scan(char *bp, struct passwd *pw, int flags)
82 {
83 uid_t id;
84 int root;
85 char *ep, *p, *sh;
86 unsigned long temp;
87
88 if (pw_big_ids_warning == -1)
89 pw_big_ids_warning = getenv("PW_SCAN_BIG_IDS") == NULL ? 1 : 0;
90
91 pw->pw_fields = 0;
92 if (!(pw->pw_name = strsep(&bp, ":"))) /* login */
93 goto fmt;
94 root = !strcmp(pw->pw_name, "root");
95 if (pw->pw_name[0] && (pw->pw_name[0] != '+' || pw->pw_name[1] == '\0'))
96 pw->pw_fields |= _PWF_NAME;
97
98 if (!(pw->pw_passwd = strsep(&bp, ":"))) /* passwd */
99 goto fmt;
100 if (pw->pw_passwd[0])
101 pw->pw_fields |= _PWF_PASSWD;
102
103 if (!(p = strsep(&bp, ":"))) /* uid */
104 goto fmt;
105 if (p[0])
106 pw->pw_fields |= _PWF_UID;
107 else {
108 if (pw->pw_name[0] != '+' && pw->pw_name[0] != '-') {
109 if (flags & _PWSCAN_WARN)
110 warnx("no uid for user %s", pw->pw_name);
111 return (0);
112 }
113 }
114 errno = 0;
115 temp = strtoul(p, &ep, 10);
116 if ((temp == ULONG_MAX && errno == ERANGE) || temp > UID_MAX) {
117 if (flags & _PWSCAN_WARN)
118 warnx("%s > max uid value (%u)", p, UID_MAX);
119 return (0);
120 }
121 id = temp;
122 if (*ep != '\0') {
123 if (flags & _PWSCAN_WARN)
124 warnx("%s uid is incorrect", p);
125 return (0);
126 }
127 if (root && id) {
128 if (flags & _PWSCAN_WARN)
129 warnx("root uid should be 0");
130 return (0);
131 }
132 if (flags & _PWSCAN_WARN && pw_big_ids_warning && id > USHRT_MAX) {
133 warnx("%s > recommended max uid value (%u)", p, USHRT_MAX);
134 /*return (0);*/ /* THIS SHOULD NOT BE FATAL! */
135 }
136 pw->pw_uid = id;
137
138 if (!(p = strsep(&bp, ":"))) /* gid */
139 goto fmt;
140 if (p[0])
141 pw->pw_fields |= _PWF_GID;
142 else {
143 if (pw->pw_name[0] != '+' && pw->pw_name[0] != '-') {
144 if (flags & _PWSCAN_WARN)
145 warnx("no gid for user %s", pw->pw_name);
146 return (0);
147 }
148 }
149 errno = 0;
150 temp = strtoul(p, &ep, 10);
151 if ((temp == ULONG_MAX && errno == ERANGE) || temp > GID_MAX) {
152 if (flags & _PWSCAN_WARN)
153 warnx("%s > max gid value (%u)", p, GID_MAX);
154 return (0);
155 }
156 id = temp;
157 if (*ep != '\0') {
158 if (flags & _PWSCAN_WARN)
159 warnx("%s gid is incorrect", p);
160 return (0);
161 }
162 if (flags & _PWSCAN_WARN && pw_big_ids_warning && id > USHRT_MAX) {
163 warnx("%s > recommended max gid value (%u)", p, USHRT_MAX);
164 /* return (0); This should not be fatal! */
165 }
166 pw->pw_gid = id;
167
168 if (flags & _PWSCAN_MASTER ) {
169 if (!(pw->pw_class = strsep(&bp, ":"))) /* class */
170 goto fmt;
171 if (pw->pw_class[0])
172 pw->pw_fields |= _PWF_CLASS;
173
174 if (!(p = strsep(&bp, ":"))) /* change */
175 goto fmt;
176 if (p[0])
177 pw->pw_fields |= _PWF_CHANGE;
178 pw->pw_change = atol(p);
179
180 if (!(p = strsep(&bp, ":"))) /* expire */
181 goto fmt;
182 if (p[0])
183 pw->pw_fields |= _PWF_EXPIRE;
184 pw->pw_expire = atol(p);
185 }
186 if (!(pw->pw_gecos = strsep(&bp, ":"))) /* gecos */
187 goto fmt;
188 if (pw->pw_gecos[0])
189 pw->pw_fields |= _PWF_GECOS;
190
191 if (!(pw->pw_dir = strsep(&bp, ":"))) /* directory */
192 goto fmt;
193 if (pw->pw_dir[0])
194 pw->pw_fields |= _PWF_DIR;
195
196 if (!(pw->pw_shell = strsep(&bp, ":"))) /* shell */
197 goto fmt;
198
199 p = pw->pw_shell;
200 if (root && *p) { /* empty == /bin/sh */
201 for (setusershell();;) {
202 if (!(sh = getusershell())) {
203 if (flags & _PWSCAN_WARN)
204 warnx("warning, unknown root shell");
205 break;
206 }
207 if (!strcmp(p, sh))
208 break;
209 }
210 endusershell();
211 }
212 if (p[0])
213 pw->pw_fields |= _PWF_SHELL;
214
215 if ((p = strsep(&bp, ":"))) { /* too many */
216 fmt:
217 if (flags & _PWSCAN_WARN)
218 warnx("corrupted entry");
219 return (0);
220 }
221 return (1);
222 }
223