Commit | Line | Data |
---|---|---|
14aa5a05 PH |
1 | /* |
2 | * Copyright (c) 2004 Andrey Panin <pazke@donpac.ru> | |
9242a7e8 | 3 | * Copyright (c) 2006-2017 The Exim Maintainers |
14aa5a05 PH |
4 | * |
5 | * This program is free software; you can redistribute it and/or modify | |
6 | * it under the terms of the GNU General Public License as published | |
7 | * by the Free Software Foundation; either version 2 of the License, or | |
8 | * (at your option) any later version. | |
9 | */ | |
10 | ||
57c2c631 PH |
11 | /* A number of modifications have been made to the original code. Originally I |
12 | commented them specially, but now they are getting quite extensive, so I have | |
13 | ceased doing that. The biggest change is to use unbuffered I/O on the socket | |
14 | because using C buffered I/O gives problems on some operating systems. PH */ | |
15 | ||
3f1df0e3 PP |
16 | /* Protocol specifications: |
17 | * Dovecot 1, protocol version 1.1 | |
18 | * http://wiki.dovecot.org/Authentication%20Protocol | |
19 | * | |
20 | * Dovecot 2, protocol version 1.1 | |
21 | * http://wiki2.dovecot.org/Design/AuthProtocol | |
22 | */ | |
23 | ||
14aa5a05 PH |
24 | #include "../exim.h" |
25 | #include "dovecot.h" | |
26 | ||
27 | #define VERSION_MAJOR 1 | |
28 | #define VERSION_MINOR 0 | |
29 | ||
3f1df0e3 PP |
30 | /* http://wiki.dovecot.org/Authentication%20Protocol |
31 | "The maximum line length isn't defined, | |
32 | but it's currently expected to fit into 8192 bytes" | |
33 | */ | |
34 | #define DOVECOT_AUTH_MAXLINELEN 8192 | |
35 | ||
36 | /* This was hard-coded as 8. | |
37 | AUTH req C->S sends {"AUTH", id, mechanism, service } + params, 5 defined for | |
38 | Dovecot 1; Dovecot 2 (same protocol version) defines 9. | |
39 | ||
40 | Master->Server sends {"USER", id, userid} + params, 6 defined. | |
41 | Server->Client only gives {"OK", id} + params, unspecified, only 1 guaranteed. | |
42 | ||
43 | We only define here to accept S->C; max seen is 3+<unspecified>, plus the two | |
44 | for the command and id, where unspecified might include _at least_ user=... | |
45 | ||
46 | So: allow for more fields than we ever expect to see, while aware that count | |
47 | can go up without changing protocol version. | |
48 | The cost is the length of an array of pointers on the stack. | |
49 | */ | |
50 | #define DOVECOT_AUTH_MAXFIELDCOUNT 16 | |
51 | ||
14aa5a05 PH |
52 | /* Options specific to the authentication mechanism. */ |
53 | optionlist auth_dovecot_options[] = { | |
54 | { | |
57c2c631 PH |
55 | "server_socket", |
56 | opt_stringptr, | |
57 | (void *)(offsetof(auth_dovecot_options_block, server_socket)) | |
14aa5a05 PH |
58 | }, |
59 | }; | |
60 | ||
61 | /* Size of the options list. An extern variable has to be used so that its | |
62 | address can appear in the tables drtables.c. */ | |
57c2c631 | 63 | |
14aa5a05 PH |
64 | int auth_dovecot_options_count = |
65 | sizeof(auth_dovecot_options) / sizeof(optionlist); | |
66 | ||
67 | /* Default private options block for the authentication method. */ | |
57c2c631 | 68 | |
14aa5a05 PH |
69 | auth_dovecot_options_block auth_dovecot_option_defaults = { |
70 | NULL, /* server_socket */ | |
71 | }; | |
72 | ||
57c2c631 | 73 | |
d185889f JH |
74 | |
75 | ||
76 | #ifdef MACRO_PREDEF | |
77 | ||
78 | /* Dummy values */ | |
79 | void auth_dovecot_init(auth_instance *ablock) {} | |
80 | int auth_dovecot_server(auth_instance *ablock, uschar *data) {return 0;} | |
81 | int auth_dovecot_client(auth_instance *ablock, smtp_inblock *inblock, | |
82 | smtp_outblock *outblock, int timeout, uschar *buffer, int buffsize) {return 0;} | |
83 | ||
84 | #else /*!MACRO_PREDEF*/ | |
85 | ||
86 | ||
57c2c631 PH |
87 | /* Static variables for reading from the socket */ |
88 | ||
89 | static uschar sbuffer[256]; | |
3f1df0e3 | 90 | static int socket_buffer_left; |
57c2c631 PH |
91 | |
92 | ||
93 | ||
14aa5a05 PH |
94 | /************************************************* |
95 | * Initialization entry point * | |
96 | *************************************************/ | |
97 | ||
98 | /* Called for each instance, after its options have been read, to | |
99 | enable consistency checks to be done, or anything else that needs | |
100 | to be set up. */ | |
57c2c631 | 101 | |
14aa5a05 PH |
102 | void auth_dovecot_init(auth_instance *ablock) |
103 | { | |
104 | auth_dovecot_options_block *ob = | |
105 | (auth_dovecot_options_block *)(ablock->options_block); | |
106 | ||
107 | if (ablock->public_name == NULL) | |
108 | ablock->public_name = ablock->name; | |
109 | if (ob->server_socket != NULL) | |
110 | ablock->server = TRUE; | |
111 | ablock->client = FALSE; | |
112 | } | |
113 | ||
3f1df0e3 PP |
114 | /************************************************* |
115 | * "strcut" to split apart server lines * | |
116 | *************************************************/ | |
117 | ||
118 | /* Dovecot auth protocol uses TAB \t as delimiter; a line consists | |
119 | of a command-name, TAB, and then any parameters, each separated by a TAB. | |
120 | A parameter can be param=value or a bool, just param. | |
121 | ||
122 | This function modifies the original str in-place, inserting NUL characters. | |
123 | It initialises ptrs entries, setting all to NULL and only setting | |
124 | non-NULL N entries, where N is the return value, the number of fields seen | |
125 | (one more than the number of tabs). | |
126 | ||
127 | Note that the return value will always be at least 1, is the count of | |
128 | actual fields (so last valid offset into ptrs is one less). | |
129 | */ | |
130 | ||
131 | static int | |
132 | strcut(uschar *str, uschar **ptrs, int nptrs) | |
14aa5a05 | 133 | { |
3f1df0e3 | 134 | uschar *last_sub_start = str; |
14aa5a05 PH |
135 | int n; |
136 | ||
137 | for (n = 0; n < nptrs; n++) | |
138 | ptrs[n] = NULL; | |
139 | n = 1; | |
140 | ||
141 | while (*str) { | |
142 | if (*str == '\t') { | |
143 | if (n <= nptrs) { | |
3f1df0e3 PP |
144 | *ptrs++ = last_sub_start; |
145 | last_sub_start = str + 1; | |
146 | *str = '\0'; | |
14aa5a05 PH |
147 | } |
148 | n++; | |
149 | } | |
150 | str++; | |
151 | } | |
152 | ||
970ba64f PP |
153 | /* It's acceptable for the string to end with a tab character. We see |
154 | this in AUTH PLAIN without an initial response from the client, which | |
155 | causing us to send "334 " and get the data from the client. */ | |
156 | if (n <= nptrs) { | |
157 | *ptrs = last_sub_start; | |
3f1df0e3 | 158 | } else { |
970ba64f PP |
159 | HDEBUG(D_auth) debug_printf("dovecot: warning: too many results from tab-splitting; saw %d fields, room for %d\n", n, nptrs); |
160 | n = nptrs; | |
3f1df0e3 PP |
161 | } |
162 | ||
163 | return n <= nptrs ? n : nptrs; | |
164 | } | |
14aa5a05 | 165 | |
3f1df0e3 PP |
166 | static void debug_strcut(uschar **ptrs, int nlen, int alen) ARG_UNUSED; |
167 | static void | |
168 | debug_strcut(uschar **ptrs, int nlen, int alen) | |
169 | { | |
170 | int i; | |
171 | debug_printf("%d read but unreturned bytes; strcut() gave %d results: ", | |
172 | socket_buffer_left, nlen); | |
173 | for (i = 0; i < nlen; i++) { | |
174 | debug_printf(" {%s}", ptrs[i]); | |
175 | } | |
176 | if (nlen < alen) | |
177 | debug_printf(" last is %s\n", ptrs[i] ? ptrs[i] : US"<null>"); | |
178 | else | |
179 | debug_printf(" (max for capacity)\n"); | |
14aa5a05 PH |
180 | } |
181 | ||
182 | #define CHECK_COMMAND(str, arg_min, arg_max) do { \ | |
57c2c631 | 183 | if (strcmpic(US(str), args[0]) != 0) \ |
14aa5a05 PH |
184 | goto out; \ |
185 | if (nargs - 1 < (arg_min)) \ | |
186 | goto out; \ | |
6c588e74 | 187 | if ( (arg_max != -1) && (nargs - 1 > (arg_max)) ) \ |
14aa5a05 PH |
188 | goto out; \ |
189 | } while (0) | |
190 | ||
191 | #define OUT(msg) do { \ | |
192 | auth_defer_msg = (US msg); \ | |
193 | goto out; \ | |
194 | } while(0) | |
195 | ||
7befa435 PH |
196 | |
197 | ||
14aa5a05 | 198 | /************************************************* |
57c2c631 PH |
199 | * "fgets" to read directly from socket * |
200 | *************************************************/ | |
201 | ||
202 | /* Added by PH after a suggestion by Steve Usher because the previous use of | |
203 | C-style buffered I/O gave trouble. */ | |
204 | ||
205 | static uschar * | |
206 | dc_gets(uschar *s, int n, int fd) | |
207 | { | |
208 | int p = 0; | |
209 | int count = 0; | |
210 | ||
211 | for (;;) | |
212 | { | |
3f1df0e3 | 213 | if (socket_buffer_left == 0) |
57c2c631 | 214 | { |
3f1df0e3 PP |
215 | socket_buffer_left = read(fd, sbuffer, sizeof(sbuffer)); |
216 | if (socket_buffer_left == 0) { if (count == 0) return NULL; else break; } | |
51473862 | 217 | p = 0; |
57c2c631 PH |
218 | } |
219 | ||
3f1df0e3 | 220 | while (p < socket_buffer_left) |
57c2c631 PH |
221 | { |
222 | if (count >= n - 1) break; | |
223 | s[count++] = sbuffer[p]; | |
224 | if (sbuffer[p++] == '\n') break; | |
225 | } | |
226 | ||
3f1df0e3 PP |
227 | memmove(sbuffer, sbuffer + p, socket_buffer_left - p); |
228 | socket_buffer_left -= p; | |
57c2c631 PH |
229 | |
230 | if (s[count-1] == '\n' || count >= n - 1) break; | |
231 | } | |
232 | ||
3f1df0e3 | 233 | s[count] = '\0'; |
57c2c631 PH |
234 | return s; |
235 | } | |
236 | ||
237 | ||
238 | ||
239 | ||
240 | /************************************************* | |
241 | * Server entry point * | |
242 | *************************************************/ | |
14aa5a05 | 243 | |
96f5fe4c JH |
244 | int |
245 | auth_dovecot_server(auth_instance * ablock, uschar * data) | |
14aa5a05 | 246 | { |
96f5fe4c JH |
247 | auth_dovecot_options_block *ob = |
248 | (auth_dovecot_options_block *) ablock->options_block; | |
249 | struct sockaddr_un sa; | |
250 | uschar buffer[DOVECOT_AUTH_MAXLINELEN]; | |
251 | uschar *args[DOVECOT_AUTH_MAXFIELDCOUNT]; | |
252 | uschar *auth_command; | |
253 | uschar *auth_extra_data = US""; | |
254 | uschar *p; | |
255 | int nargs, tmp; | |
77560253 | 256 | int crequid = 1, cont = 1, fd = -1, ret = DEFER; |
96f5fe4c JH |
257 | BOOL found = FALSE, have_mech_line = FALSE; |
258 | ||
259 | HDEBUG(D_auth) debug_printf("dovecot authentication\n"); | |
260 | ||
261 | if (!data) | |
262 | { | |
263 | ret = FAIL; | |
264 | goto out; | |
265 | } | |
14aa5a05 | 266 | |
96f5fe4c JH |
267 | memset(&sa, 0, sizeof(sa)); |
268 | sa.sun_family = AF_UNIX; | |
14aa5a05 | 269 | |
96f5fe4c JH |
270 | /* This was the original code here: it is nonsense because strncpy() |
271 | does not return an integer. I have converted this to use the function | |
272 | that formats and checks length. PH */ | |
14aa5a05 | 273 | |
96f5fe4c JH |
274 | /* |
275 | if (strncpy(sa.sun_path, ob->server_socket, sizeof(sa.sun_path)) < 0) { | |
276 | } | |
277 | */ | |
14aa5a05 | 278 | |
96f5fe4c JH |
279 | if (!string_format(US sa.sun_path, sizeof(sa.sun_path), "%s", |
280 | ob->server_socket)) | |
281 | { | |
282 | auth_defer_msg = US"authentication socket path too long"; | |
283 | return DEFER; | |
284 | } | |
7befa435 | 285 | |
96f5fe4c | 286 | auth_defer_msg = US"authentication socket connection error"; |
7befa435 | 287 | |
96f5fe4c JH |
288 | if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) |
289 | return DEFER; | |
7befa435 | 290 | |
96f5fe4c JH |
291 | if (connect(fd, (struct sockaddr *) &sa, sizeof(sa)) < 0) |
292 | goto out; | |
7befa435 | 293 | |
96f5fe4c | 294 | auth_defer_msg = US"authentication socket protocol error"; |
14aa5a05 | 295 | |
96f5fe4c JH |
296 | socket_buffer_left = 0; /* Global, used to read more than a line but return by line */ |
297 | while (cont) | |
298 | { | |
299 | if (dc_gets(buffer, sizeof(buffer), fd) == NULL) | |
300 | OUT("authentication socket read error or premature eof"); | |
301 | p = buffer + Ustrlen(buffer) - 1; | |
302 | if (*p != '\n') | |
303 | OUT("authentication socket protocol line too long"); | |
304 | ||
305 | *p = '\0'; | |
306 | HDEBUG(D_auth) debug_printf("received: %s\n", buffer); | |
307 | ||
308 | nargs = strcut(buffer, args, sizeof(args) / sizeof(args[0])); | |
309 | ||
310 | /* HDEBUG(D_auth) debug_strcut(args, nargs, sizeof(args) / sizeof(args[0])); */ | |
311 | ||
312 | /* Code below rewritten by Kirill Miazine (km@krot.org). Only check commands that | |
313 | Exim will need. Original code also failed if Dovecot server sent unknown | |
314 | command. E.g. COOKIE in version 1.1 of the protocol would cause troubles. */ | |
315 | /* pdp: note that CUID is a per-connection identifier sent by the server, | |
316 | which increments at server discretion. | |
317 | By contrast, the "id" field of the protocol is a connection-specific request | |
318 | identifier, which needs to be unique per request from the client and is not | |
319 | connected to the CUID value, so we ignore CUID from server. It's purely for | |
320 | diagnostics. */ | |
321 | ||
322 | if (Ustrcmp(args[0], US"VERSION") == 0) | |
323 | { | |
324 | CHECK_COMMAND("VERSION", 2, 2); | |
325 | if (Uatoi(args[1]) != VERSION_MAJOR) | |
326 | OUT("authentication socket protocol version mismatch"); | |
327 | } | |
328 | else if (Ustrcmp(args[0], US"MECH") == 0) | |
329 | { | |
330 | CHECK_COMMAND("MECH", 1, INT_MAX); | |
331 | have_mech_line = TRUE; | |
332 | if (strcmpic(US args[1], ablock->public_name) == 0) | |
333 | found = TRUE; | |
334 | } | |
335 | else if (Ustrcmp(args[0], US"SPID") == 0) | |
336 | { | |
337 | /* Unfortunately the auth protocol handshake wasn't designed well | |
338 | to differentiate between auth-client/userdb/master. auth-userdb | |
339 | and auth-master send VERSION + SPID lines only and nothing | |
340 | afterwards, while auth-client sends VERSION + MECH + SPID + | |
341 | CUID + more. The simplest way that we can determine if we've | |
342 | connected to the correct socket is to see if MECH line exists or | |
343 | not (alternatively we'd have to have a small timeout after SPID | |
344 | to see if CUID is sent or not). */ | |
345 | ||
346 | if (!have_mech_line) | |
347 | OUT("authentication socket type mismatch" | |
348 | " (connected to auth-master instead of auth-client)"); | |
349 | } | |
350 | else if (Ustrcmp(args[0], US"DONE") == 0) | |
351 | { | |
352 | CHECK_COMMAND("DONE", 0, 0); | |
353 | cont = 0; | |
354 | } | |
355 | } | |
14aa5a05 | 356 | |
96f5fe4c JH |
357 | if (!found) |
358 | { | |
359 | auth_defer_msg = string_sprintf( | |
360 | "Dovecot did not advertise mechanism \"%s\" to us", ablock->public_name); | |
361 | goto out; | |
362 | } | |
14aa5a05 | 363 | |
96f5fe4c JH |
364 | /* Added by PH: data must not contain tab (as it is |
365 | b64 it shouldn't, but check for safety). */ | |
57c2c631 | 366 | |
96f5fe4c JH |
367 | if (Ustrchr(data, '\t') != NULL) |
368 | { | |
369 | ret = FAIL; | |
370 | goto out; | |
371 | } | |
14aa5a05 | 372 | |
96f5fe4c JH |
373 | /* Added by PH: extra fields when TLS is in use or if the TCP/IP |
374 | connection is local. */ | |
6c588e74 | 375 | |
96f5fe4c JH |
376 | if (tls_in.cipher != NULL) |
377 | auth_extra_data = string_sprintf("secured\t%s%s", | |
378 | tls_in.certificate_verified? "valid-client-cert" : "", | |
379 | tls_in.certificate_verified? "\t" : ""); | |
14aa5a05 | 380 | |
96f5fe4c JH |
381 | else if ( interface_address != NULL |
382 | && Ustrcmp(sender_host_address, interface_address) == 0) | |
383 | auth_extra_data = US"secured\t"; | |
14aa5a05 | 384 | |
14aa5a05 | 385 | |
96f5fe4c JH |
386 | /**************************************************************************** |
387 | The code below was the original code here. It didn't work. A reading of the | |
388 | file auth-protocol.txt.gz that came with Dovecot 1.0_beta8 indicated that | |
389 | this was not right. Maybe something changed. I changed it to move the | |
390 | service indication into the AUTH command, and it seems to be better. PH | |
391 | ||
392 | fprintf(f, "VERSION\t%d\t%d\r\nSERVICE\tSMTP\r\nCPID\t%d\r\n" | |
393 | "AUTH\t%d\t%s\trip=%s\tlip=%s\tresp=%s\r\n", | |
394 | VERSION_MAJOR, VERSION_MINOR, getpid(), cuid, | |
395 | ablock->public_name, sender_host_address, interface_address, | |
5903c6ff | 396 | data ? CS data : ""); |
96f5fe4c JH |
397 | |
398 | Subsequently, the command was modified to add "secured" and "valid-client- | |
399 | cert" when relevant. | |
400 | ****************************************************************************/ | |
14aa5a05 | 401 | |
96f5fe4c JH |
402 | auth_command = string_sprintf("VERSION\t%d\t%d\nCPID\t%d\n" |
403 | "AUTH\t%d\t%s\tservice=smtp\t%srip=%s\tlip=%s\tnologin\tresp=%s\n", | |
404 | VERSION_MAJOR, VERSION_MINOR, getpid(), crequid, | |
405 | ablock->public_name, auth_extra_data, sender_host_address, | |
406 | interface_address, data); | |
14aa5a05 | 407 | |
96f5fe4c JH |
408 | if (write(fd, auth_command, Ustrlen(auth_command)) < 0) |
409 | HDEBUG(D_auth) debug_printf("error sending auth_command: %s\n", | |
410 | strerror(errno)); | |
7befa435 | 411 | |
96f5fe4c | 412 | HDEBUG(D_auth) debug_printf("sent: %s", auth_command); |
7befa435 | 413 | |
96f5fe4c JH |
414 | while (1) |
415 | { | |
416 | uschar *temp; | |
417 | uschar *auth_id_pre = NULL; | |
418 | int i; | |
14aa5a05 | 419 | |
96f5fe4c JH |
420 | if (dc_gets(buffer, sizeof(buffer), fd) == NULL) |
421 | { | |
422 | auth_defer_msg = US"authentication socket read error or premature eof"; | |
423 | goto out; | |
424 | } | |
6c588e74 | 425 | |
96f5fe4c JH |
426 | buffer[Ustrlen(buffer) - 1] = 0; |
427 | HDEBUG(D_auth) debug_printf("received: %s\n", buffer); | |
428 | nargs = strcut(buffer, args, sizeof(args) / sizeof(args[0])); | |
6c588e74 | 429 | |
96f5fe4c JH |
430 | if (Uatoi(args[1]) != crequid) |
431 | OUT("authentication socket connection id mismatch"); | |
14aa5a05 | 432 | |
96f5fe4c JH |
433 | switch (toupper(*args[0])) |
434 | { | |
435 | case 'C': | |
436 | CHECK_COMMAND("CONT", 1, 2); | |
437 | ||
438 | if ((tmp = auth_get_no64_data(&data, US args[2])) != OK) | |
439 | { | |
440 | ret = tmp; | |
441 | goto out; | |
442 | } | |
443 | ||
444 | /* Added by PH: data must not contain tab (as it is | |
445 | b64 it shouldn't, but check for safety). */ | |
446 | ||
447 | if (Ustrchr(data, '\t') != NULL) | |
448 | { | |
449 | ret = FAIL; | |
450 | goto out; | |
451 | } | |
452 | ||
453 | temp = string_sprintf("CONT\t%d\t%s\n", crequid, data); | |
454 | if (write(fd, temp, Ustrlen(temp)) < 0) | |
455 | OUT("authentication socket write error"); | |
456 | break; | |
457 | ||
458 | case 'F': | |
459 | CHECK_COMMAND("FAIL", 1, -1); | |
460 | ||
461 | for (i=2; (i<nargs) && (auth_id_pre == NULL); i++) | |
462 | { | |
463 | if ( Ustrncmp(args[i], US"user=", 5) == 0 ) | |
464 | { | |
465 | auth_id_pre = args[i]+5; | |
466 | expand_nstring[1] = auth_vars[0] = string_copy(auth_id_pre); /* PH */ | |
467 | expand_nlength[1] = Ustrlen(auth_id_pre); | |
468 | expand_nmax = 1; | |
469 | } | |
470 | } | |
471 | ||
472 | ret = FAIL; | |
473 | goto out; | |
474 | ||
475 | case 'O': | |
476 | CHECK_COMMAND("OK", 2, -1); | |
477 | ||
478 | /* Search for the "user=$USER" string in the args array | |
479 | and return the proper value. */ | |
480 | ||
481 | for (i=2; (i<nargs) && (auth_id_pre == NULL); i++) | |
482 | { | |
483 | if ( Ustrncmp(args[i], US"user=", 5) == 0 ) | |
484 | { | |
485 | auth_id_pre = args[i]+5; | |
486 | expand_nstring[1] = auth_vars[0] = string_copy(auth_id_pre); /* PH */ | |
487 | expand_nlength[1] = Ustrlen(auth_id_pre); | |
488 | expand_nmax = 1; | |
489 | } | |
490 | } | |
491 | ||
492 | if (auth_id_pre == NULL) | |
493 | OUT("authentication socket protocol error, username missing"); | |
494 | ||
495 | ret = OK; | |
496 | /* fallthrough */ | |
497 | ||
498 | default: | |
499 | goto out; | |
500 | } | |
501 | } | |
14aa5a05 | 502 | |
57c2c631 | 503 | out: |
96f5fe4c JH |
504 | /* close the socket used by dovecot */ |
505 | if (fd >= 0) | |
506 | close(fd); | |
16ff981e | 507 | |
96f5fe4c JH |
508 | /* Expand server_condition as an authorization check */ |
509 | return ret == OK ? auth_check_serv_cond(ablock) : ret; | |
14aa5a05 | 510 | } |
d185889f JH |
511 | |
512 | ||
513 | #endif /*!MACRO_PREDEF*/ |