1 /* $NetBSD: iruserok.c,v 1.2 2017/01/28 21:31:50 christos Exp $ */
2
3 /*
4 * Copyright (c) 1983, 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 #include <config.h>
33
34 #include <stdio.h>
35 #include <ctype.h>
36 #ifdef HAVE_SYS_TYPES_H
37 #include <sys/types.h>
38 #endif
39 #ifdef HAVE_NETINET_IN_H
40 #include <netinet/in.h>
41 #endif
42 #ifdef HAVE_NETINET_IN6_H
43 #include <netinet/in6.h>
44 #endif
45 #ifdef HAVE_NETINET6_IN6_H
46 #include <netinet6/in6.h>
47 #endif
48 #ifdef HAVE_RPCSVC_YPCLNT_H
49 #include <rpcsvc/ypclnt.h>
50 #endif
51
52 #include <krb5/roken.h>
53
54 int __check_rhosts_file = 1;
55 char *__rcmd_errstr = 0;
56
57 /*
58 * Returns "true" if match, 0 if no match.
59 */
60 static
61 int
__icheckhost(unsigned raddr,const char * lhost)62 __icheckhost(unsigned raddr, const char *lhost)
63 {
64 struct hostent *hp;
65 u_long laddr;
66 char **pp;
67
68 /* Try for raw ip address first. */
69 if (isdigit((unsigned char)*lhost)
70 && (long)(laddr = inet_addr(lhost)) != -1)
71 return (raddr == laddr);
72
73 /* Better be a hostname. */
74 if ((hp = gethostbyname(lhost)) == NULL)
75 return (0);
76
77 /* Spin through ip addresses. */
78 for (pp = hp->h_addr_list; *pp; ++pp)
79 if (memcmp(&raddr, *pp, sizeof(u_long)) == 0)
80 return (1);
81
82 /* No match. */
83 return (0);
84 }
85
86 /*
87 * Returns 0 if ok, -1 if not ok.
88 */
89 static
90 int
__ivaliduser(FILE * hostf,unsigned raddr,const char * luser,const char * ruser)91 __ivaliduser(FILE *hostf, unsigned raddr, const char *luser,
92 const char *ruser)
93 {
94 char *user, *p;
95 int ch;
96 char buf[MaxHostNameLen + 128]; /* host + login */
97 char hname[MaxHostNameLen];
98 struct hostent *hp;
99 /* Presumed guilty until proven innocent. */
100 int userok = 0, hostok = 0;
101 #ifdef HAVE_YP_GET_DEFAULT_DOMAIN
102 char *ypdomain;
103
104 if (yp_get_default_domain(&ypdomain))
105 ypdomain = NULL;
106 #else
107 #define ypdomain NULL
108 #endif
109 /* We need to get the damn hostname back for netgroup matching. */
110 if ((hp = gethostbyaddr((char *)&raddr,
111 sizeof(u_long),
112 AF_INET)) == NULL)
113 return (-1);
114 strlcpy(hname, hp->h_name, sizeof(hname));
115
116 while (fgets(buf, sizeof(buf), hostf)) {
117 p = buf;
118 /* Skip lines that are too long. */
119 if (strchr(p, '\n') == NULL) {
120 while ((ch = getc(hostf)) != '\n' && ch != EOF);
121 continue;
122 }
123 if (*p == '\n' || *p == '#') {
124 /* comment... */
125 continue;
126 }
127 while (*p != '\n' && *p != ' ' && *p != '\t' && *p != '\0') {
128 if (isupper((unsigned char)*p))
129 *p = tolower((unsigned char)*p);
130 p++;
131 }
132 if (*p == ' ' || *p == '\t') {
133 *p++ = '\0';
134 while (*p == ' ' || *p == '\t')
135 p++;
136 user = p;
137 while (*p != '\n' && *p != ' ' &&
138 *p != '\t' && *p != '\0')
139 p++;
140 } else
141 user = p;
142 *p = '\0';
143 /*
144 * Do +/- and +@/-@ checking. This looks really nasty,
145 * but it matches SunOS's behavior so far as I can tell.
146 */
147 switch(buf[0]) {
148 case '+':
149 if (!buf[1]) { /* '+' matches all hosts */
150 hostok = 1;
151 break;
152 }
153 if (buf[1] == '@') /* match a host by netgroup */
154 hostok = innetgr((char *)&buf[2],
155 (char *)&hname, NULL, ypdomain);
156 else /* match a host by addr */
157 hostok = __icheckhost(raddr,(char *)&buf[1]);
158 break;
159 case '-': /* reject '-' hosts and all their users */
160 if (buf[1] == '@') {
161 if (innetgr((char *)&buf[2],
162 (char *)&hname, NULL, ypdomain))
163 return(-1);
164 } else {
165 if (__icheckhost(raddr,(char *)&buf[1]))
166 return(-1);
167 }
168 break;
169 default: /* if no '+' or '-', do a simple match */
170 hostok = __icheckhost(raddr, buf);
171 break;
172 }
173 switch(*user) {
174 case '+':
175 if (!*(user+1)) { /* '+' matches all users */
176 userok = 1;
177 break;
178 }
179 if (*(user+1) == '@') /* match a user by netgroup */
180 userok = innetgr(user+2, NULL, (char *)ruser,
181 ypdomain);
182 else /* match a user by direct specification */
183 userok = !(strcmp(ruser, user+1));
184 break;
185 case '-': /* if we matched a hostname, */
186 if (hostok) { /* check for user field rejections */
187 if (!*(user+1))
188 return(-1);
189 if (*(user+1) == '@') {
190 if (innetgr(user+2, NULL,
191 (char *)ruser, ypdomain))
192 return(-1);
193 } else {
194 if (!strcmp(ruser, user+1))
195 return(-1);
196 }
197 }
198 break;
199 default: /* no rejections: try to match the user */
200 if (hostok)
201 userok = !(strcmp(ruser,*user ? user : luser));
202 break;
203 }
204 if (hostok && userok)
205 return(0);
206 }
207 return (-1);
208 }
209
210 /*
211 * New .rhosts strategy: We are passed an ip address. We spin through
212 * hosts.equiv and .rhosts looking for a match. When the .rhosts only
213 * has ip addresses, we don't have to trust a nameserver. When it
214 * contains hostnames, we spin through the list of addresses the nameserver
215 * gives us and look for a match.
216 *
217 * Returns 0 if ok, -1 if not ok.
218 */
219 ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
iruserok(unsigned raddr,int superuser,const char * ruser,const char * luser)220 iruserok(unsigned raddr, int superuser, const char *ruser, const char *luser)
221 {
222 char *cp;
223 struct stat sbuf;
224 struct passwd *pwd;
225 FILE *hostf;
226 uid_t uid;
227 int first;
228 char pbuf[MaxPathLen];
229
230 first = 1;
231 hostf = superuser ? NULL : fopen(_PATH_HEQUIV, "r");
232 again:
233 if (hostf) {
234 if (__ivaliduser(hostf, raddr, luser, ruser) == 0) {
235 fclose(hostf);
236 return (0);
237 }
238 fclose(hostf);
239 }
240 if (first == 1 && (__check_rhosts_file || superuser)) {
241 first = 0;
242 if ((pwd = k_getpwnam((char*)luser)) == NULL)
243 return (-1);
244 snprintf (pbuf, sizeof(pbuf), "%s/.rhosts", pwd->pw_dir);
245
246 /*
247 * Change effective uid while opening .rhosts. If root and
248 * reading an NFS mounted file system, can't read files that
249 * are protected read/write owner only.
250 */
251 uid = geteuid();
252 if (seteuid(pwd->pw_uid) < 0)
253 return (-1);
254 hostf = fopen(pbuf, "r");
255 seteuid(uid);
256
257 if (hostf == NULL)
258 return (-1);
259 /*
260 * If not a regular file, or is owned by someone other than
261 * user or root or if writeable by anyone but the owner, quit.
262 */
263 cp = NULL;
264 if (lstat(pbuf, &sbuf) < 0)
265 cp = ".rhosts lstat failed";
266 else if (!S_ISREG(sbuf.st_mode))
267 cp = ".rhosts not regular file";
268 else if (fstat(fileno(hostf), &sbuf) < 0)
269 cp = ".rhosts fstat failed";
270 else if (sbuf.st_uid && sbuf.st_uid != pwd->pw_uid)
271 cp = "bad .rhosts owner";
272 else if (sbuf.st_mode & (S_IWGRP|S_IWOTH))
273 cp = ".rhosts writeable by other than owner";
274 /* If there were any problems, quit. */
275 if (cp) {
276 __rcmd_errstr = cp;
277 fclose(hostf);
278 return (-1);
279 }
280 goto again;
281 }
282 return (-1);
283 }
284