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718bc25c | 1 | /* |
2 | * $Source$ | |
3 | * $Author$ | |
4 | * $Header$ | |
5 | * | |
6 | * Copyright (C) 1987 by the Massachusetts Institute of Technology | |
babbc197 | 7 | * For copying and distribution information, please see the file |
8 | * <mit-copyright.h>. | |
718bc25c | 9 | * |
10 | * Utility functions for communication with the Kerberos admin_server | |
11 | * | |
12 | * Original version written by Jeffery I. Schiller, January 1987 | |
13 | * Completely gutted and rewritten by Bill Sommerfeld, August 1987 | |
14 | * | |
718bc25c | 15 | */ |
16 | ||
17 | #ifndef lint | |
18 | static char *rcsid_admin_call_c = "$Header$"; | |
19 | #endif lint | |
20 | ||
babbc197 | 21 | #include <mit-copyright.h> |
718bc25c | 22 | #include <sys/errno.h> |
23 | #include <sys/types.h> | |
24 | #include <sys/time.h> | |
25 | #include <sys/ioctl.h> | |
26 | #include <sys/socket.h> | |
27 | #include <netinet/in.h> | |
28 | ||
29 | #include <netdb.h> | |
30 | #include <strings.h> | |
8670255d | 31 | #include <ctype.h> |
718bc25c | 32 | #include <stdio.h> |
33 | ||
34 | #include "admin_err.h" | |
35 | #include "admin_server.h" | |
36 | #include "prot.h" | |
37 | #include "krb.h" | |
a205ca20 | 38 | #include "krb_et.h" |
718bc25c | 39 | |
718bc25c | 40 | extern int errno; /* System call error numbers */ |
41 | ||
42 | extern long gethostid(); | |
43 | ||
44 | static u_char *strapp(); /* string append function */ | |
45 | ||
46 | static int inited = 0; /* are we initialized? */ | |
47 | static int admin_fd = -1; /* socket to talk to admin_server. */ | |
48 | ||
49 | static struct sockaddr_in admin_addr; /* address of admin server. */ | |
50 | static struct sockaddr_in my_addr; /* address bound to admin_fd. */ | |
51 | static int my_addr_len; /* size of above address. */ | |
52 | ||
53 | static char krbrlm[REALM_SZ]; /* Local kerberos realm */ | |
71a6c578 | 54 | static char krbhost[BUFSIZ]; /* Name of server for local realm */ |
074685e3 | 55 | char admin_errmsg[BUFSIZ]; /* Server error message */ |
718bc25c | 56 | |
57 | /* | |
58 | * Initialize socket, etc. to use to talk to admin_server. | |
59 | */ | |
60 | ||
61 | int admin_call_init() | |
62 | { | |
63 | register int status = 0; | |
64 | ||
65 | if (!inited) { | |
66 | struct hostent *hp; /* host to talk to */ | |
67 | struct servent *sp; /* service to talk to */ | |
3004ebdb | 68 | |
a205ca20 | 69 | initialize_kadm_error_table(); |
84638166 | 70 | if (status = krb_get_lrealm(krbrlm, 1)) { |
a205ca20 | 71 | status += ERROR_TABLE_BASE_krb; |
718bc25c | 72 | goto punt; |
73 | } | |
74 | ||
75 | /* | |
76 | * Locate server. | |
77 | */ | |
78 | ||
84638166 | 79 | if (status = krb_get_krbhst(krbhost, krbrlm, 1)) { |
a205ca20 | 80 | status += ERROR_TABLE_BASE_krb; |
71a6c578 | 81 | goto punt; |
82 | } | |
83 | hp = gethostbyname(krbhost); | |
718bc25c | 84 | if (!hp) { |
85 | status = ADMIN_UNKNOWN_HOST; | |
86 | goto punt; | |
87 | } | |
88 | sp = getservbyname("atest3", "udp"); | |
89 | if (!sp) { | |
90 | status = ADMIN_UNKNOWN_SERVICE; | |
91 | goto punt; | |
92 | } | |
93 | bzero((char *)&admin_addr, sizeof(admin_addr)); | |
94 | admin_addr.sin_family = hp->h_addrtype; | |
95 | bcopy((char *)hp->h_addr, (char *)&admin_addr.sin_addr, hp->h_length); | |
96 | admin_addr.sin_port = sp->s_port; | |
97 | ||
8670255d | 98 | /* lowercase & truncate hostname becuase it will be used as an |
99 | * instance name. | |
100 | */ | |
101 | { | |
102 | char *s; | |
103 | for (s = krbhost; *s && *s != '.'; s++) | |
104 | if (isupper(*s)) | |
105 | *s = tolower(*s); | |
106 | *s = 0; | |
107 | } | |
718bc25c | 108 | inited = 1; |
109 | } | |
110 | return 0; | |
111 | ||
112 | punt: | |
113 | (void) close(admin_fd); | |
114 | admin_fd = -1; | |
115 | return status; | |
116 | } | |
117 | ||
118 | /* | |
119 | * Build and transmit request to admin_server, and wait for | |
120 | * response from server. Returns a standard error code. | |
121 | */ | |
122 | ||
123 | int | |
124 | admin_call(opcode, pname, old_passwd, new_passwd, crypt_passwd) | |
125 | int opcode; | |
126 | char *pname; | |
127 | char *old_passwd; | |
128 | char *new_passwd; | |
129 | char *crypt_passwd; | |
130 | { | |
131 | int status; | |
132 | register u_char *bp; /* Pointer into buffer. */ | |
133 | u_char *ep; /* End of buffer pointer. */ | |
134 | ||
135 | u_char pvt_buf[BUFSIZ]; /* private message plaintext */ | |
136 | int pvt_len; /* length of valid data in pvt_buf */ | |
137 | ||
138 | u_char sealed_buf[BUFSIZ]; /* sealed version of private message */ | |
139 | int sealed_len; /* length of valid data in sealed_buf */ | |
140 | ||
141 | u_long checksum; /* quad_cksum of sealed request. */ | |
142 | ||
143 | C_Block sess_key; /* Session key. */ | |
144 | Key_schedule sess_sched; /* Key schedule for above. */ | |
145 | ||
146 | CREDENTIALS cred; /* Kerberos credentials. */ | |
147 | KTEXT_ST authent; /* Authenticator */ | |
148 | KTEXT_ST reply; /* Reply from admin_server */ | |
149 | MSG_DAT msg_data; /* Decrypted message */ | |
150 | int attempts; /* Number of retransmits so far */ | |
151 | ||
152 | struct sockaddr rec_addr; /* Address we got reply from */ | |
153 | int rec_addr_len; /* Length of that address */ | |
3004ebdb | 154 | int on = 1; /* ioctl argument */ |
155 | ||
718bc25c | 156 | |
157 | if (!inited) { | |
158 | status = admin_call_init(); | |
159 | if (status) goto bad; | |
160 | } | |
161 | ||
162 | /* | |
163 | * assemble packet: | |
164 | * | |
165 | * sealed message consists of: | |
166 | * version number (one byte). | |
167 | * request code (one byte). | |
168 | * principal name (null terminated). | |
169 | * new password (in the clear, null terminated). | |
170 | * old password or instance (null terminated) | |
171 | * crypt(new password, seed) (null terminated). | |
172 | * an extra null. | |
173 | * a '\001' character. | |
174 | * This is all sealed inside a private_message, with an | |
175 | * authenticator tacked on in front. | |
176 | */ | |
177 | ||
178 | bp = pvt_buf; | |
179 | ep = pvt_buf + sizeof(pvt_buf); | |
180 | ||
181 | *bp++ = PW_SRV_VERSION; | |
182 | *bp++ = opcode; | |
183 | if ((bp = strapp(bp, (u_char *)pname, ep)) && | |
184 | (bp = strapp(bp, (u_char *)new_passwd, ep)) && | |
185 | (bp = strapp(bp, (u_char *)old_passwd, ep)) && | |
186 | (bp = strapp(bp, (u_char *)crypt_passwd, ep))) { | |
187 | *bp++ = '\0'; | |
188 | *bp++ = '\1'; | |
189 | pvt_len = bp - pvt_buf; | |
190 | } else { | |
191 | status = ADMIN_TOO_LONG; | |
192 | goto bad; | |
193 | } | |
194 | ||
195 | /* | |
196 | * find our session key. | |
197 | */ | |
198 | ||
8670255d | 199 | if (status = krb_get_cred("changepw", krbhost, krbrlm, &cred)) { |
a205ca20 | 200 | status += ERROR_TABLE_BASE_krb; |
718bc25c | 201 | goto bad; |
202 | } | |
203 | ||
204 | bcopy((char *)cred.session, (char *)sess_key, sizeof(sess_key)); | |
205 | bzero((char *)cred.session, sizeof(sess_key)); /* lest we remember */ | |
206 | ||
207 | if(key_sched(sess_key, sess_sched)) { | |
208 | status = ADMIN_BAD_KEY; | |
209 | goto bad; | |
210 | } | |
211 | ||
3004ebdb | 212 | /* |
213 | * Set up socket. | |
214 | */ | |
215 | ||
216 | admin_fd = socket(admin_addr.sin_family, SOCK_DGRAM, 0); | |
217 | if (admin_fd < 0) { | |
218 | status = errno; | |
219 | goto bad; | |
220 | } | |
221 | ||
222 | bzero((char *)&my_addr, sizeof(my_addr)); | |
223 | ||
224 | my_addr.sin_family = admin_addr.sin_family; | |
225 | my_addr.sin_addr.s_addr = gethostid(); | |
226 | ||
227 | if (bind(admin_fd, &my_addr, sizeof(my_addr)) < 0) { | |
228 | status = errno; | |
229 | goto bad; | |
230 | } | |
231 | ||
232 | my_addr_len = sizeof(my_addr); | |
233 | ||
234 | if (getsockname(admin_fd, (struct sockaddr *)&my_addr, | |
235 | &my_addr_len) < 0) { | |
236 | status = errno; | |
237 | goto bad; | |
238 | } | |
239 | ||
240 | if (ioctl(admin_fd, FIONBIO, (char *)&on) < 0) { | |
241 | status = errno; | |
242 | goto bad; | |
243 | } | |
244 | ||
718bc25c | 245 | /* |
246 | * Encrypt the message using the session key. | |
247 | * Since this contains passwords, it must be kept from prying eyes. | |
248 | */ | |
249 | ||
e5fdb505 | 250 | sealed_len = krb_mk_priv(pvt_buf, sealed_buf, pvt_len, |
718bc25c | 251 | sess_sched, sess_key, &my_addr, |
252 | &admin_addr); | |
253 | if (sealed_len < 0) { | |
254 | status = ADMIN_CANT_ENCRYPT; | |
255 | goto bad; | |
256 | } | |
257 | ||
258 | /* | |
259 | * Checksum the cypher text, to guard against tampering in flight. | |
260 | */ | |
261 | ||
262 | checksum = quad_cksum(sealed_buf, NULL, sealed_len, 0, sess_key); | |
263 | ||
264 | /* | |
265 | * Make an authenticator, so the server can learn the session key | |
266 | * and know who we are. | |
267 | */ | |
268 | ||
8670255d | 269 | if (status = krb_mk_req(&authent, "changepw", krbhost, krbrlm, |
718bc25c | 270 | checksum)) { |
a205ca20 | 271 | status += ERROR_TABLE_BASE_krb; |
718bc25c | 272 | goto bad; |
273 | } | |
274 | ||
275 | /* | |
276 | * Add the sealed message to the end of the authenticator. | |
277 | */ | |
278 | ||
279 | if ((authent.length + sealed_len) > MAX_KTXT_LEN) { | |
280 | status = ADMIN_TOO_LONG; | |
281 | goto bad; | |
282 | } | |
283 | ||
284 | bcopy(sealed_buf, authent.dat + authent.length, sealed_len); | |
285 | authent.length += sealed_len; | |
286 | ||
287 | /* | |
288 | * send it off, and wait for a reply. | |
289 | */ | |
290 | ||
291 | attempts = 0; | |
292 | ||
293 | while (attempts++ < RETRY_LIMIT) { | |
294 | int active; /* number of active fds (from select). */ | |
295 | fd_set set; /* interesting fd's. */ | |
296 | struct timeval timeout; /* timeout on select. */ | |
297 | ||
298 | if (sendto(admin_fd, (char *)authent.dat, authent.length, | |
299 | 0, &admin_addr, sizeof(admin_addr)) != authent.length) { | |
300 | status = errno; | |
301 | goto bad; | |
302 | } | |
303 | ||
304 | FD_ZERO(&set); | |
305 | FD_SET(admin_fd, &set); | |
306 | ||
307 | timeout.tv_sec = USER_TIMEOUT; | |
308 | timeout.tv_usec = 0; | |
309 | ||
310 | active = select(admin_fd+1, &set, (fd_set *)0, (fd_set *)0, &timeout); | |
311 | if (active < 0) { | |
312 | status = errno; | |
313 | goto bad; | |
314 | } else if (active == 0) continue; | |
315 | else { | |
316 | reply.length = recvfrom(admin_fd, (char *)reply.dat, | |
317 | sizeof(reply.dat), 0, | |
318 | &rec_addr, &rec_addr_len); | |
319 | if (reply.length < 0) continue; | |
320 | #ifdef notdef | |
321 | if (!bcmp(&rec_addr, &admin_addr, sizeof(admin_addr))) | |
322 | /* the spoofers are out in force.. */ | |
323 | continue; | |
324 | #endif notdef | |
325 | break; /* got one.. */ | |
326 | } | |
327 | } | |
328 | ||
329 | if (attempts > RETRY_LIMIT) { | |
330 | status = ETIMEDOUT; | |
331 | goto bad; | |
332 | } | |
333 | ||
334 | if (pkt_version((&reply)) != KRB_PROT_VERSION) { | |
335 | status = ADMIN_BAD_VERSION; | |
336 | goto bad; | |
337 | } | |
338 | ||
339 | if ((pkt_msg_type((&reply)) & ~1) != AUTH_MSG_PRIVATE) { | |
340 | bp = reply.dat; | |
341 | if (*bp++ != KRB_PROT_VERSION) { | |
342 | status = ADMIN_BAD_VERSION; | |
343 | goto bad; | |
344 | } | |
345 | if (*bp++ != AUTH_MSG_ERR_REPLY) { | |
346 | status = ADMIN_UNKNOWN_CODE; | |
347 | goto bad; | |
348 | } | |
349 | bp += strlen((char *)bp) + 1; /* Skip name */ | |
350 | bp += strlen((char *)bp) + 1; /* Skip instance */ | |
351 | bp += strlen((char *)bp) + 1; /* Skip realm */ | |
352 | ||
353 | /* null-terminate error string */ | |
354 | reply.dat[reply.length] = '\0'; | |
355 | ||
356 | if (*bp++ == 126) { | |
357 | status = ADMIN_SERVER_ERROR; | |
358 | strcpy(admin_errmsg, bp); | |
359 | goto bad; | |
360 | } else { | |
361 | status = ADMIN_UNKNOWN_CODE; | |
362 | goto bad; | |
363 | } | |
364 | } | |
e5fdb505 | 365 | status = krb_rd_priv(reply.dat, reply.length, |
718bc25c | 366 | sess_sched, sess_key, |
367 | &admin_addr, &my_addr, | |
368 | &msg_data); | |
369 | if (status) { | |
a205ca20 | 370 | status += ERROR_TABLE_BASE_krb; |
718bc25c | 371 | goto bad; |
372 | } | |
373 | bp = msg_data.app_data; | |
374 | ||
375 | if (*bp++ != PW_SRV_VERSION) { | |
376 | status = ADMIN_BAD_VERSION; | |
377 | goto bad; | |
378 | } | |
379 | if (*bp++ != INSTALL_REPLY) { | |
380 | status = ADMIN_UNKNOWN_CODE; | |
381 | goto bad; | |
382 | } | |
383 | ||
384 | status = 0; | |
385 | /* fall through into cleanup */ | |
386 | ||
387 | bad: | |
388 | /* | |
389 | * Paranoia: shred all the incriminating evidence. | |
390 | * We'll let the caller shred the arguments. | |
391 | */ | |
392 | bzero((char *)sess_key, sizeof(sess_key)); | |
393 | bzero((char *)sess_sched, sizeof(sess_sched)); | |
394 | bzero(pvt_buf, sizeof(pvt_buf)); | |
3004ebdb | 395 | |
396 | if (admin_fd >= 0) { | |
397 | (void) close(admin_fd); | |
398 | admin_fd = -1; | |
399 | } | |
400 | ||
718bc25c | 401 | return status; |
402 | } | |
403 | ||
404 | /* | |
405 | * Copies characters from source to dest, returning a pointer to the | |
406 | * point in dest after the last character copied from source. | |
407 | * If this would be greater than end, no characters are copied, and NULL | |
408 | * is returned instead. | |
409 | */ | |
410 | ||
411 | static u_char *strapp(dest, source, end) | |
412 | register u_char *dest, *source, *end; | |
413 | { | |
414 | register int length = strlen(source) + 1; | |
415 | if (dest+length > end) return NULL; | |
416 | else { | |
417 | bcopy(source, dest, length); | |
418 | return dest + length; | |
419 | } | |
420 | } |