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 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 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 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 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 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 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