1 /*
2 * Copyright (c) 1983, 1993, 1994
3 * The Regents of the University of California. All rights reserved.
4 *
5 * %sccs.include.redist.c%
6 */
7
8 #if defined(LIBC_SCCS) && !defined(lint)
9 static char sccsid[] = "@(#)rcmd.c 8.3 (Berkeley) 03/26/94";
10 #endif /* LIBC_SCCS and not lint */
11
12 #include <sys/param.h>
13 #include <sys/socket.h>
14 #include <sys/stat.h>
15
16 #include <netinet/in.h>
17 #include <arpa/inet.h>
18
19 #include <signal.h>
20 #include <fcntl.h>
21 #include <netdb.h>
22 #include <unistd.h>
23 #include <pwd.h>
24 #include <errno.h>
25 #include <stdio.h>
26 #include <ctype.h>
27 #include <string.h>
28
29 int __ivaliduser __P((FILE *, u_long, const char *, const char *));
30 static int __icheckhost __P((u_long, char *));
31
32 int
rcmd(ahost,rport,locuser,remuser,cmd,fd2p)33 rcmd(ahost, rport, locuser, remuser, cmd, fd2p)
34 char **ahost;
35 u_short rport;
36 const char *locuser, *remuser, *cmd;
37 int *fd2p;
38 {
39 struct hostent *hp;
40 struct sockaddr_in sin, from;
41 fd_set reads;
42 long oldmask;
43 pid_t pid;
44 int s, lport, timo;
45 char c;
46
47 pid = getpid();
48 hp = gethostbyname(*ahost);
49 if (hp == NULL) {
50 herror(*ahost);
51 return (-1);
52 }
53 *ahost = hp->h_name;
54 oldmask = sigblock(sigmask(SIGURG));
55 for (timo = 1, lport = IPPORT_RESERVED - 1;;) {
56 s = rresvport(&lport);
57 if (s < 0) {
58 if (errno == EAGAIN)
59 (void)fprintf(stderr,
60 "rcmd: socket: All ports in use\n");
61 else
62 (void)fprintf(stderr, "rcmd: socket: %s\n",
63 strerror(errno));
64 sigsetmask(oldmask);
65 return (-1);
66 }
67 fcntl(s, F_SETOWN, pid);
68 sin.sin_family = hp->h_addrtype;
69 bcopy(hp->h_addr_list[0], &sin.sin_addr, hp->h_length);
70 sin.sin_port = rport;
71 if (connect(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0)
72 break;
73 (void)close(s);
74 if (errno == EADDRINUSE) {
75 lport--;
76 continue;
77 }
78 if (errno == ECONNREFUSED && timo <= 16) {
79 (void)sleep(timo);
80 timo *= 2;
81 continue;
82 }
83 if (hp->h_addr_list[1] != NULL) {
84 int oerrno = errno;
85
86 (void)fprintf(stderr, "connect to address %s: ",
87 inet_ntoa(sin.sin_addr));
88 errno = oerrno;
89 perror(0);
90 hp->h_addr_list++;
91 bcopy(hp->h_addr_list[0], &sin.sin_addr, hp->h_length);
92 (void)fprintf(stderr, "Trying %s...\n",
93 inet_ntoa(sin.sin_addr));
94 continue;
95 }
96 (void)fprintf(stderr, "%s: %s\n", hp->h_name, strerror(errno));
97 sigsetmask(oldmask);
98 return (-1);
99 }
100 lport--;
101 if (fd2p == 0) {
102 write(s, "", 1);
103 lport = 0;
104 } else {
105 char num[8];
106 int s2 = rresvport(&lport), s3;
107 int len = sizeof(from);
108
109 if (s2 < 0)
110 goto bad;
111 listen(s2, 1);
112 (void)snprintf(num, sizeof(num), "%d", lport);
113 if (write(s, num, strlen(num)+1) != strlen(num)+1) {
114 (void)fprintf(stderr,
115 "rcmd: write (setting up stderr): %s\n",
116 strerror(errno));
117 (void)close(s2);
118 goto bad;
119 }
120 FD_ZERO(&reads);
121 FD_SET(s, &reads);
122 FD_SET(s2, &reads);
123 errno = 0;
124 if (select(32, &reads, 0, 0, 0) < 1 || !FD_ISSET(s2, &reads)) {
125 if (errno != 0)
126 (void)fprintf(stderr,
127 "rcmd: select (setting up stderr): %s\n",
128 strerror(errno));
129 else
130 (void)fprintf(stderr,
131 "select: protocol failure in circuit setup\n");
132 (void)close(s2);
133 goto bad;
134 }
135 s3 = accept(s2, (struct sockaddr *)&from, &len);
136 (void)close(s2);
137 if (s3 < 0) {
138 (void)fprintf(stderr,
139 "rcmd: accept: %s\n", strerror(errno));
140 lport = 0;
141 goto bad;
142 }
143 *fd2p = s3;
144 from.sin_port = ntohs((u_short)from.sin_port);
145 if (from.sin_family != AF_INET ||
146 from.sin_port >= IPPORT_RESERVED ||
147 from.sin_port < IPPORT_RESERVED / 2) {
148 (void)fprintf(stderr,
149 "socket: protocol failure in circuit setup.\n");
150 goto bad2;
151 }
152 }
153 (void)write(s, locuser, strlen(locuser)+1);
154 (void)write(s, remuser, strlen(remuser)+1);
155 (void)write(s, cmd, strlen(cmd)+1);
156 if (read(s, &c, 1) != 1) {
157 (void)fprintf(stderr,
158 "rcmd: %s: %s\n", *ahost, strerror(errno));
159 goto bad2;
160 }
161 if (c != 0) {
162 while (read(s, &c, 1) == 1) {
163 (void)write(STDERR_FILENO, &c, 1);
164 if (c == '\n')
165 break;
166 }
167 goto bad2;
168 }
169 sigsetmask(oldmask);
170 return (s);
171 bad2:
172 if (lport)
173 (void)close(*fd2p);
174 bad:
175 (void)close(s);
176 sigsetmask(oldmask);
177 return (-1);
178 }
179
180 int
rresvport(alport)181 rresvport(alport)
182 int *alport;
183 {
184 struct sockaddr_in sin;
185 int s;
186
187 sin.sin_family = AF_INET;
188 sin.sin_addr.s_addr = INADDR_ANY;
189 s = socket(AF_INET, SOCK_STREAM, 0);
190 if (s < 0)
191 return (-1);
192 for (;;) {
193 sin.sin_port = htons((u_short)*alport);
194 if (bind(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0)
195 return (s);
196 if (errno != EADDRINUSE) {
197 (void)close(s);
198 return (-1);
199 }
200 (*alport)--;
201 if (*alport == IPPORT_RESERVED/2) {
202 (void)close(s);
203 errno = EAGAIN; /* close */
204 return (-1);
205 }
206 }
207 }
208
209 int __check_rhosts_file = 1;
210 char *__rcmd_errstr;
211
212 int
ruserok(rhost,superuser,ruser,luser)213 ruserok(rhost, superuser, ruser, luser)
214 const char *rhost, *ruser, *luser;
215 int superuser;
216 {
217 struct hostent *hp;
218 u_long addr;
219 char **ap;
220
221 if ((hp = gethostbyname(rhost)) == NULL)
222 return (-1);
223 for (ap = hp->h_addr_list; *ap; ++ap) {
224 bcopy(*ap, &addr, sizeof(addr));
225 if (iruserok(addr, superuser, ruser, luser) == 0)
226 return (0);
227 }
228 return (-1);
229 }
230
231 /*
232 * New .rhosts strategy: We are passed an ip address. We spin through
233 * hosts.equiv and .rhosts looking for a match. When the .rhosts only
234 * has ip addresses, we don't have to trust a nameserver. When it
235 * contains hostnames, we spin through the list of addresses the nameserver
236 * gives us and look for a match.
237 *
238 * Returns 0 if ok, -1 if not ok.
239 */
240 int
iruserok(raddr,superuser,ruser,luser)241 iruserok(raddr, superuser, ruser, luser)
242 u_long raddr;
243 int superuser;
244 const char *ruser, *luser;
245 {
246 register char *cp;
247 struct stat sbuf;
248 struct passwd *pwd;
249 FILE *hostf;
250 uid_t uid;
251 int first;
252 char pbuf[MAXPATHLEN];
253
254 first = 1;
255 hostf = superuser ? NULL : fopen(_PATH_HEQUIV, "r");
256 again:
257 if (hostf) {
258 if (__ivaliduser(hostf, raddr, luser, ruser) == 0) {
259 (void)fclose(hostf);
260 return (0);
261 }
262 (void)fclose(hostf);
263 }
264 if (first == 1 && (__check_rhosts_file || superuser)) {
265 first = 0;
266 if ((pwd = getpwnam(luser)) == NULL)
267 return (-1);
268 (void)strcpy(pbuf, pwd->pw_dir);
269 (void)strcat(pbuf, "/.rhosts");
270
271 /*
272 * Change effective uid while opening .rhosts. If root and
273 * reading an NFS mounted file system, can't read files that
274 * are protected read/write owner only.
275 */
276 uid = geteuid();
277 (void)seteuid(pwd->pw_uid);
278 hostf = fopen(pbuf, "r");
279 (void)seteuid(uid);
280
281 if (hostf == NULL)
282 return (-1);
283 /*
284 * If not a regular file, or is owned by someone other than
285 * user or root or if writeable by anyone but the owner, quit.
286 */
287 cp = NULL;
288 if (lstat(pbuf, &sbuf) < 0)
289 cp = ".rhosts lstat failed";
290 else if (!S_ISREG(sbuf.st_mode))
291 cp = ".rhosts not regular file";
292 else if (fstat(fileno(hostf), &sbuf) < 0)
293 cp = ".rhosts fstat failed";
294 else if (sbuf.st_uid && sbuf.st_uid != pwd->pw_uid)
295 cp = "bad .rhosts owner";
296 else if (sbuf.st_mode & (S_IWGRP|S_IWOTH))
297 cp = ".rhosts writeable by other than owner";
298 /* If there were any problems, quit. */
299 if (cp) {
300 __rcmd_errstr = cp;
301 (void)fclose(hostf);
302 return (-1);
303 }
304 goto again;
305 }
306 return (-1);
307 }
308
309 /*
310 * XXX
311 * Don't make static, used by lpd(8).
312 *
313 * Returns 0 if ok, -1 if not ok.
314 */
315 int
__ivaliduser(hostf,raddr,luser,ruser)316 __ivaliduser(hostf, raddr, luser, ruser)
317 FILE *hostf;
318 u_long raddr;
319 const char *luser, *ruser;
320 {
321 register char *user, *p;
322 int ch;
323 char buf[MAXHOSTNAMELEN + 128]; /* host + login */
324
325 while (fgets(buf, sizeof(buf), hostf)) {
326 p = buf;
327 /* Skip lines that are too long. */
328 if (strchr(p, '\n') == NULL) {
329 while ((ch = getc(hostf)) != '\n' && ch != EOF);
330 continue;
331 }
332 while (*p != '\n' && *p != ' ' && *p != '\t' && *p != '\0') {
333 *p = isupper(*p) ? tolower(*p) : *p;
334 p++;
335 }
336 if (*p == ' ' || *p == '\t') {
337 *p++ = '\0';
338 while (*p == ' ' || *p == '\t')
339 p++;
340 user = p;
341 while (*p != '\n' && *p != ' ' &&
342 *p != '\t' && *p != '\0')
343 p++;
344 } else
345 user = p;
346 *p = '\0';
347 if (__icheckhost(raddr, buf) &&
348 strcmp(ruser, *user ? user : luser) == 0) {
349 return (0);
350 }
351 }
352 return (-1);
353 }
354
355 /*
356 * Returns "true" if match, 0 if no match.
357 */
358 static int
__icheckhost(raddr,lhost)359 __icheckhost(raddr, lhost)
360 u_long raddr;
361 register char *lhost;
362 {
363 register struct hostent *hp;
364 register u_long laddr;
365 register char **pp;
366
367 /* Try for raw ip address first. */
368 if (isdigit(*lhost) && (long)(laddr = inet_addr(lhost)) != -1)
369 return (raddr == laddr);
370
371 /* Better be a hostname. */
372 if ((hp = gethostbyname(lhost)) == NULL)
373 return (0);
374
375 /* Spin through ip addresses. */
376 for (pp = hp->h_addr_list; *pp; ++pp)
377 if (!bcmp(&raddr, *pp, sizeof(u_long)))
378 return (1);
379
380 /* No match. */
381 return (0);
382 }
383