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 | |
c71c454d | 64 | int auth_dovecot_options_count = nelem(auth_dovecot_options); |
14aa5a05 PH |
65 | |
66 | /* Default private options block for the authentication method. */ | |
57c2c631 | 67 | |
14aa5a05 PH |
68 | auth_dovecot_options_block auth_dovecot_option_defaults = { |
69 | NULL, /* server_socket */ | |
70 | }; | |
71 | ||
57c2c631 | 72 | |
d185889f JH |
73 | |
74 | ||
75 | #ifdef MACRO_PREDEF | |
76 | ||
77 | /* Dummy values */ | |
78 | void auth_dovecot_init(auth_instance *ablock) {} | |
79 | int auth_dovecot_server(auth_instance *ablock, uschar *data) {return 0;} | |
251b9eb4 JH |
80 | int auth_dovecot_client(auth_instance *ablock, void * sx, |
81 | int timeout, uschar *buffer, int buffsize) {return 0;} | |
d185889f JH |
82 | |
83 | #else /*!MACRO_PREDEF*/ | |
84 | ||
85 | ||
57c2c631 PH |
86 | /* Static variables for reading from the socket */ |
87 | ||
88 | static uschar sbuffer[256]; | |
3f1df0e3 | 89 | static int socket_buffer_left; |
57c2c631 PH |
90 | |
91 | ||
92 | ||
14aa5a05 PH |
93 | /************************************************* |
94 | * Initialization entry point * | |
95 | *************************************************/ | |
96 | ||
97 | /* Called for each instance, after its options have been read, to | |
98 | enable consistency checks to be done, or anything else that needs | |
99 | to be set up. */ | |
57c2c631 | 100 | |
14aa5a05 PH |
101 | void auth_dovecot_init(auth_instance *ablock) |
102 | { | |
c71c454d JH |
103 | auth_dovecot_options_block *ob = |
104 | (auth_dovecot_options_block *)(ablock->options_block); | |
105 | ||
106 | if (!ablock->public_name) ablock->public_name = ablock->name; | |
107 | if (ob->server_socket) ablock->server = TRUE; | |
108 | ablock->client = FALSE; | |
14aa5a05 PH |
109 | } |
110 | ||
3f1df0e3 PP |
111 | /************************************************* |
112 | * "strcut" to split apart server lines * | |
113 | *************************************************/ | |
114 | ||
115 | /* Dovecot auth protocol uses TAB \t as delimiter; a line consists | |
116 | of a command-name, TAB, and then any parameters, each separated by a TAB. | |
117 | A parameter can be param=value or a bool, just param. | |
118 | ||
119 | This function modifies the original str in-place, inserting NUL characters. | |
120 | It initialises ptrs entries, setting all to NULL and only setting | |
121 | non-NULL N entries, where N is the return value, the number of fields seen | |
122 | (one more than the number of tabs). | |
123 | ||
124 | Note that the return value will always be at least 1, is the count of | |
125 | actual fields (so last valid offset into ptrs is one less). | |
126 | */ | |
127 | ||
128 | static int | |
129 | strcut(uschar *str, uschar **ptrs, int nptrs) | |
14aa5a05 | 130 | { |
d7978c0f JH |
131 | uschar *last_sub_start = str; |
132 | int n; | |
133 | ||
134 | for (n = 0; n < nptrs; n++) | |
135 | ptrs[n] = NULL; | |
136 | n = 1; | |
137 | ||
138 | while (*str) | |
c71c454d JH |
139 | if (*str++ == '\t') |
140 | if (n++ <= nptrs) | |
d7978c0f JH |
141 | { |
142 | *ptrs++ = last_sub_start; | |
c71c454d JH |
143 | last_sub_start = str; |
144 | str[-1] = '\0'; | |
d7978c0f | 145 | } |
d7978c0f JH |
146 | |
147 | /* It's acceptable for the string to end with a tab character. We see | |
148 | this in AUTH PLAIN without an initial response from the client, which | |
149 | causing us to send "334 " and get the data from the client. */ | |
150 | if (n <= nptrs) | |
c71c454d | 151 | *ptrs = last_sub_start; |
d7978c0f | 152 | else |
c71c454d JH |
153 | { |
154 | HDEBUG(D_auth) | |
155 | debug_printf("dovecot: warning: too many results from tab-splitting;" | |
156 | " saw %d fields, room for %d\n", n, nptrs); | |
157 | n = nptrs; | |
158 | } | |
d7978c0f JH |
159 | |
160 | return n <= nptrs ? n : nptrs; | |
3f1df0e3 | 161 | } |
14aa5a05 | 162 | |
3f1df0e3 PP |
163 | static void debug_strcut(uschar **ptrs, int nlen, int alen) ARG_UNUSED; |
164 | static void | |
165 | debug_strcut(uschar **ptrs, int nlen, int alen) | |
166 | { | |
d7978c0f JH |
167 | int i; |
168 | debug_printf("%d read but unreturned bytes; strcut() gave %d results: ", | |
169 | socket_buffer_left, nlen); | |
170 | for (i = 0; i < nlen; i++) | |
171 | debug_printf(" {%s}", ptrs[i]); | |
172 | if (nlen < alen) | |
173 | debug_printf(" last is %s\n", ptrs[i] ? ptrs[i] : US"<null>"); | |
174 | else | |
175 | debug_printf(" (max for capacity)\n"); | |
14aa5a05 PH |
176 | } |
177 | ||
178 | #define CHECK_COMMAND(str, arg_min, arg_max) do { \ | |
57c2c631 | 179 | if (strcmpic(US(str), args[0]) != 0) \ |
14aa5a05 PH |
180 | goto out; \ |
181 | if (nargs - 1 < (arg_min)) \ | |
182 | goto out; \ | |
6c588e74 | 183 | if ( (arg_max != -1) && (nargs - 1 > (arg_max)) ) \ |
14aa5a05 PH |
184 | goto out; \ |
185 | } while (0) | |
186 | ||
187 | #define OUT(msg) do { \ | |
188 | auth_defer_msg = (US msg); \ | |
189 | goto out; \ | |
190 | } while(0) | |
191 | ||
7befa435 PH |
192 | |
193 | ||
14aa5a05 | 194 | /************************************************* |
57c2c631 PH |
195 | * "fgets" to read directly from socket * |
196 | *************************************************/ | |
197 | ||
198 | /* Added by PH after a suggestion by Steve Usher because the previous use of | |
199 | C-style buffered I/O gave trouble. */ | |
200 | ||
201 | static uschar * | |
202 | dc_gets(uschar *s, int n, int fd) | |
203 | { | |
204 | int p = 0; | |
205 | int count = 0; | |
206 | ||
207 | for (;;) | |
208 | { | |
3f1df0e3 | 209 | if (socket_buffer_left == 0) |
57c2c631 | 210 | { |
c9f1be94 BL |
211 | if ((socket_buffer_left = read(fd, sbuffer, sizeof(sbuffer))) <= 0) |
212 | if (count == 0) return NULL; else break; | |
51473862 | 213 | p = 0; |
57c2c631 PH |
214 | } |
215 | ||
3f1df0e3 | 216 | while (p < socket_buffer_left) |
57c2c631 PH |
217 | { |
218 | if (count >= n - 1) break; | |
219 | s[count++] = sbuffer[p]; | |
220 | if (sbuffer[p++] == '\n') break; | |
221 | } | |
222 | ||
3f1df0e3 PP |
223 | memmove(sbuffer, sbuffer + p, socket_buffer_left - p); |
224 | socket_buffer_left -= p; | |
57c2c631 PH |
225 | |
226 | if (s[count-1] == '\n' || count >= n - 1) break; | |
227 | } | |
228 | ||
3f1df0e3 | 229 | s[count] = '\0'; |
57c2c631 PH |
230 | return s; |
231 | } | |
232 | ||
233 | ||
234 | ||
235 | ||
236 | /************************************************* | |
237 | * Server entry point * | |
238 | *************************************************/ | |
14aa5a05 | 239 | |
96f5fe4c JH |
240 | int |
241 | auth_dovecot_server(auth_instance * ablock, uschar * data) | |
14aa5a05 | 242 | { |
96f5fe4c JH |
243 | auth_dovecot_options_block *ob = |
244 | (auth_dovecot_options_block *) ablock->options_block; | |
245 | struct sockaddr_un sa; | |
246 | uschar buffer[DOVECOT_AUTH_MAXLINELEN]; | |
247 | uschar *args[DOVECOT_AUTH_MAXFIELDCOUNT]; | |
248 | uschar *auth_command; | |
249 | uschar *auth_extra_data = US""; | |
250 | uschar *p; | |
251 | int nargs, tmp; | |
77560253 | 252 | int crequid = 1, cont = 1, fd = -1, ret = DEFER; |
96f5fe4c JH |
253 | BOOL found = FALSE, have_mech_line = FALSE; |
254 | ||
255 | HDEBUG(D_auth) debug_printf("dovecot authentication\n"); | |
256 | ||
257 | if (!data) | |
258 | { | |
259 | ret = FAIL; | |
260 | goto out; | |
261 | } | |
14aa5a05 | 262 | |
96f5fe4c JH |
263 | memset(&sa, 0, sizeof(sa)); |
264 | sa.sun_family = AF_UNIX; | |
14aa5a05 | 265 | |
96f5fe4c JH |
266 | /* This was the original code here: it is nonsense because strncpy() |
267 | does not return an integer. I have converted this to use the function | |
268 | that formats and checks length. PH */ | |
14aa5a05 | 269 | |
96f5fe4c JH |
270 | /* |
271 | if (strncpy(sa.sun_path, ob->server_socket, sizeof(sa.sun_path)) < 0) { | |
272 | } | |
273 | */ | |
14aa5a05 | 274 | |
96f5fe4c JH |
275 | if (!string_format(US sa.sun_path, sizeof(sa.sun_path), "%s", |
276 | ob->server_socket)) | |
277 | { | |
278 | auth_defer_msg = US"authentication socket path too long"; | |
279 | return DEFER; | |
280 | } | |
7befa435 | 281 | |
96f5fe4c | 282 | auth_defer_msg = US"authentication socket connection error"; |
7befa435 | 283 | |
96f5fe4c JH |
284 | if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) |
285 | return DEFER; | |
7befa435 | 286 | |
96f5fe4c JH |
287 | if (connect(fd, (struct sockaddr *) &sa, sizeof(sa)) < 0) |
288 | goto out; | |
7befa435 | 289 | |
96f5fe4c | 290 | auth_defer_msg = US"authentication socket protocol error"; |
14aa5a05 | 291 | |
96f5fe4c JH |
292 | socket_buffer_left = 0; /* Global, used to read more than a line but return by line */ |
293 | while (cont) | |
294 | { | |
c71c454d | 295 | if (!dc_gets(buffer, sizeof(buffer), fd)) |
96f5fe4c JH |
296 | OUT("authentication socket read error or premature eof"); |
297 | p = buffer + Ustrlen(buffer) - 1; | |
298 | if (*p != '\n') | |
299 | OUT("authentication socket protocol line too long"); | |
300 | ||
301 | *p = '\0'; | |
302 | HDEBUG(D_auth) debug_printf("received: %s\n", buffer); | |
303 | ||
c71c454d | 304 | nargs = strcut(buffer, args, nelem(args)); |
96f5fe4c | 305 | |
c71c454d | 306 | /* HDEBUG(D_auth) debug_strcut(args, nargs, nelem(args)); */ |
96f5fe4c JH |
307 | |
308 | /* Code below rewritten by Kirill Miazine (km@krot.org). Only check commands that | |
309 | Exim will need. Original code also failed if Dovecot server sent unknown | |
310 | command. E.g. COOKIE in version 1.1 of the protocol would cause troubles. */ | |
311 | /* pdp: note that CUID is a per-connection identifier sent by the server, | |
312 | which increments at server discretion. | |
313 | By contrast, the "id" field of the protocol is a connection-specific request | |
314 | identifier, which needs to be unique per request from the client and is not | |
315 | connected to the CUID value, so we ignore CUID from server. It's purely for | |
316 | diagnostics. */ | |
317 | ||
318 | if (Ustrcmp(args[0], US"VERSION") == 0) | |
319 | { | |
320 | CHECK_COMMAND("VERSION", 2, 2); | |
321 | if (Uatoi(args[1]) != VERSION_MAJOR) | |
322 | OUT("authentication socket protocol version mismatch"); | |
323 | } | |
324 | else if (Ustrcmp(args[0], US"MECH") == 0) | |
325 | { | |
326 | CHECK_COMMAND("MECH", 1, INT_MAX); | |
327 | have_mech_line = TRUE; | |
328 | if (strcmpic(US args[1], ablock->public_name) == 0) | |
329 | found = TRUE; | |
330 | } | |
331 | else if (Ustrcmp(args[0], US"SPID") == 0) | |
332 | { | |
333 | /* Unfortunately the auth protocol handshake wasn't designed well | |
334 | to differentiate between auth-client/userdb/master. auth-userdb | |
335 | and auth-master send VERSION + SPID lines only and nothing | |
336 | afterwards, while auth-client sends VERSION + MECH + SPID + | |
337 | CUID + more. The simplest way that we can determine if we've | |
338 | connected to the correct socket is to see if MECH line exists or | |
339 | not (alternatively we'd have to have a small timeout after SPID | |
340 | to see if CUID is sent or not). */ | |
341 | ||
342 | if (!have_mech_line) | |
343 | OUT("authentication socket type mismatch" | |
344 | " (connected to auth-master instead of auth-client)"); | |
345 | } | |
346 | else if (Ustrcmp(args[0], US"DONE") == 0) | |
347 | { | |
348 | CHECK_COMMAND("DONE", 0, 0); | |
349 | cont = 0; | |
350 | } | |
351 | } | |
14aa5a05 | 352 | |
96f5fe4c JH |
353 | if (!found) |
354 | { | |
355 | auth_defer_msg = string_sprintf( | |
356 | "Dovecot did not advertise mechanism \"%s\" to us", ablock->public_name); | |
357 | goto out; | |
358 | } | |
14aa5a05 | 359 | |
96f5fe4c JH |
360 | /* Added by PH: data must not contain tab (as it is |
361 | b64 it shouldn't, but check for safety). */ | |
57c2c631 | 362 | |
96f5fe4c JH |
363 | if (Ustrchr(data, '\t') != NULL) |
364 | { | |
365 | ret = FAIL; | |
366 | goto out; | |
367 | } | |
14aa5a05 | 368 | |
96f5fe4c JH |
369 | /* Added by PH: extra fields when TLS is in use or if the TCP/IP |
370 | connection is local. */ | |
6c588e74 | 371 | |
c71c454d | 372 | if (tls_in.cipher) |
96f5fe4c | 373 | auth_extra_data = string_sprintf("secured\t%s%s", |
c71c454d JH |
374 | tls_in.certificate_verified ? "valid-client-cert" : "", |
375 | tls_in.certificate_verified ? "\t" : ""); | |
14aa5a05 | 376 | |
c71c454d | 377 | else if ( interface_address |
96f5fe4c JH |
378 | && Ustrcmp(sender_host_address, interface_address) == 0) |
379 | auth_extra_data = US"secured\t"; | |
14aa5a05 | 380 | |
14aa5a05 | 381 | |
96f5fe4c JH |
382 | /**************************************************************************** |
383 | The code below was the original code here. It didn't work. A reading of the | |
384 | file auth-protocol.txt.gz that came with Dovecot 1.0_beta8 indicated that | |
385 | this was not right. Maybe something changed. I changed it to move the | |
386 | service indication into the AUTH command, and it seems to be better. PH | |
387 | ||
388 | fprintf(f, "VERSION\t%d\t%d\r\nSERVICE\tSMTP\r\nCPID\t%d\r\n" | |
389 | "AUTH\t%d\t%s\trip=%s\tlip=%s\tresp=%s\r\n", | |
390 | VERSION_MAJOR, VERSION_MINOR, getpid(), cuid, | |
391 | ablock->public_name, sender_host_address, interface_address, | |
5903c6ff | 392 | data ? CS data : ""); |
96f5fe4c JH |
393 | |
394 | Subsequently, the command was modified to add "secured" and "valid-client- | |
395 | cert" when relevant. | |
396 | ****************************************************************************/ | |
14aa5a05 | 397 | |
96f5fe4c JH |
398 | auth_command = string_sprintf("VERSION\t%d\t%d\nCPID\t%d\n" |
399 | "AUTH\t%d\t%s\tservice=smtp\t%srip=%s\tlip=%s\tnologin\tresp=%s\n", | |
400 | VERSION_MAJOR, VERSION_MINOR, getpid(), crequid, | |
401 | ablock->public_name, auth_extra_data, sender_host_address, | |
402 | interface_address, data); | |
14aa5a05 | 403 | |
96f5fe4c JH |
404 | if (write(fd, auth_command, Ustrlen(auth_command)) < 0) |
405 | HDEBUG(D_auth) debug_printf("error sending auth_command: %s\n", | |
406 | strerror(errno)); | |
7befa435 | 407 | |
96f5fe4c | 408 | HDEBUG(D_auth) debug_printf("sent: %s", auth_command); |
7befa435 | 409 | |
96f5fe4c JH |
410 | while (1) |
411 | { | |
412 | uschar *temp; | |
413 | uschar *auth_id_pre = NULL; | |
14aa5a05 | 414 | |
c71c454d | 415 | if (!dc_gets(buffer, sizeof(buffer), fd)) |
96f5fe4c JH |
416 | { |
417 | auth_defer_msg = US"authentication socket read error or premature eof"; | |
418 | goto out; | |
419 | } | |
6c588e74 | 420 | |
96f5fe4c JH |
421 | buffer[Ustrlen(buffer) - 1] = 0; |
422 | HDEBUG(D_auth) debug_printf("received: %s\n", buffer); | |
c71c454d | 423 | nargs = strcut(buffer, args, nelem(args)); |
6c588e74 | 424 | |
96f5fe4c JH |
425 | if (Uatoi(args[1]) != crequid) |
426 | OUT("authentication socket connection id mismatch"); | |
14aa5a05 | 427 | |
96f5fe4c JH |
428 | switch (toupper(*args[0])) |
429 | { | |
430 | case 'C': | |
431 | CHECK_COMMAND("CONT", 1, 2); | |
432 | ||
433 | if ((tmp = auth_get_no64_data(&data, US args[2])) != OK) | |
434 | { | |
435 | ret = tmp; | |
436 | goto out; | |
437 | } | |
438 | ||
439 | /* Added by PH: data must not contain tab (as it is | |
440 | b64 it shouldn't, but check for safety). */ | |
441 | ||
442 | if (Ustrchr(data, '\t') != NULL) | |
443 | { | |
444 | ret = FAIL; | |
445 | goto out; | |
446 | } | |
447 | ||
448 | temp = string_sprintf("CONT\t%d\t%s\n", crequid, data); | |
449 | if (write(fd, temp, Ustrlen(temp)) < 0) | |
450 | OUT("authentication socket write error"); | |
451 | break; | |
452 | ||
453 | case 'F': | |
454 | CHECK_COMMAND("FAIL", 1, -1); | |
455 | ||
c71c454d JH |
456 | for (int i = 2; i < nargs && !auth_id_pre; i++) |
457 | if (Ustrncmp(args[i], US"user=", 5) == 0) | |
96f5fe4c | 458 | { |
c71c454d | 459 | auth_id_pre = args[i] + 5; |
96f5fe4c JH |
460 | expand_nstring[1] = auth_vars[0] = string_copy(auth_id_pre); /* PH */ |
461 | expand_nlength[1] = Ustrlen(auth_id_pre); | |
462 | expand_nmax = 1; | |
463 | } | |
96f5fe4c JH |
464 | ret = FAIL; |
465 | goto out; | |
466 | ||
467 | case 'O': | |
468 | CHECK_COMMAND("OK", 2, -1); | |
469 | ||
470 | /* Search for the "user=$USER" string in the args array | |
471 | and return the proper value. */ | |
472 | ||
c71c454d JH |
473 | for (int i = 2; i < nargs && !auth_id_pre; i++) |
474 | if (Ustrncmp(args[i], US"user=", 5) == 0) | |
96f5fe4c | 475 | { |
c71c454d | 476 | auth_id_pre = args[i] + 5; |
96f5fe4c JH |
477 | expand_nstring[1] = auth_vars[0] = string_copy(auth_id_pre); /* PH */ |
478 | expand_nlength[1] = Ustrlen(auth_id_pre); | |
479 | expand_nmax = 1; | |
480 | } | |
96f5fe4c | 481 | |
c71c454d | 482 | if (!auth_id_pre) |
96f5fe4c JH |
483 | OUT("authentication socket protocol error, username missing"); |
484 | ||
485 | ret = OK; | |
486 | /* fallthrough */ | |
487 | ||
488 | default: | |
489 | goto out; | |
490 | } | |
491 | } | |
14aa5a05 | 492 | |
57c2c631 | 493 | out: |
96f5fe4c JH |
494 | /* close the socket used by dovecot */ |
495 | if (fd >= 0) | |
496 | close(fd); | |
16ff981e | 497 | |
96f5fe4c JH |
498 | /* Expand server_condition as an authorization check */ |
499 | return ret == OK ? auth_check_serv_cond(ablock) : ret; | |
14aa5a05 | 500 | } |
d185889f JH |
501 | |
502 | ||
503 | #endif /*!MACRO_PREDEF*/ |