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[] = { | |
13a4b4c1 JH |
54 | { "server_socket", opt_stringptr, |
55 | OPT_OFF(auth_dovecot_options_block, server_socket) | |
14aa5a05 PH |
56 | }, |
57 | }; | |
58 | ||
59 | /* Size of the options list. An extern variable has to be used so that its | |
60 | address can appear in the tables drtables.c. */ | |
57c2c631 | 61 | |
c71c454d | 62 | int auth_dovecot_options_count = nelem(auth_dovecot_options); |
14aa5a05 PH |
63 | |
64 | /* Default private options block for the authentication method. */ | |
57c2c631 | 65 | |
14aa5a05 PH |
66 | auth_dovecot_options_block auth_dovecot_option_defaults = { |
67 | NULL, /* server_socket */ | |
68 | }; | |
69 | ||
57c2c631 | 70 | |
d185889f JH |
71 | |
72 | ||
73 | #ifdef MACRO_PREDEF | |
74 | ||
75 | /* Dummy values */ | |
76 | void auth_dovecot_init(auth_instance *ablock) {} | |
77 | int auth_dovecot_server(auth_instance *ablock, uschar *data) {return 0;} | |
251b9eb4 JH |
78 | int auth_dovecot_client(auth_instance *ablock, void * sx, |
79 | int timeout, uschar *buffer, int buffsize) {return 0;} | |
d185889f JH |
80 | |
81 | #else /*!MACRO_PREDEF*/ | |
82 | ||
83 | ||
57c2c631 PH |
84 | /* Static variables for reading from the socket */ |
85 | ||
86 | static uschar sbuffer[256]; | |
3f1df0e3 | 87 | static int socket_buffer_left; |
57c2c631 PH |
88 | |
89 | ||
90 | ||
14aa5a05 PH |
91 | /************************************************* |
92 | * Initialization entry point * | |
93 | *************************************************/ | |
94 | ||
95 | /* Called for each instance, after its options have been read, to | |
96 | enable consistency checks to be done, or anything else that needs | |
97 | to be set up. */ | |
57c2c631 | 98 | |
14aa5a05 PH |
99 | void auth_dovecot_init(auth_instance *ablock) |
100 | { | |
c71c454d JH |
101 | auth_dovecot_options_block *ob = |
102 | (auth_dovecot_options_block *)(ablock->options_block); | |
103 | ||
104 | if (!ablock->public_name) ablock->public_name = ablock->name; | |
105 | if (ob->server_socket) ablock->server = TRUE; | |
106 | ablock->client = FALSE; | |
14aa5a05 PH |
107 | } |
108 | ||
3f1df0e3 PP |
109 | /************************************************* |
110 | * "strcut" to split apart server lines * | |
111 | *************************************************/ | |
112 | ||
113 | /* Dovecot auth protocol uses TAB \t as delimiter; a line consists | |
114 | of a command-name, TAB, and then any parameters, each separated by a TAB. | |
115 | A parameter can be param=value or a bool, just param. | |
116 | ||
117 | This function modifies the original str in-place, inserting NUL characters. | |
118 | It initialises ptrs entries, setting all to NULL and only setting | |
119 | non-NULL N entries, where N is the return value, the number of fields seen | |
120 | (one more than the number of tabs). | |
121 | ||
122 | Note that the return value will always be at least 1, is the count of | |
123 | actual fields (so last valid offset into ptrs is one less). | |
124 | */ | |
125 | ||
126 | static int | |
127 | strcut(uschar *str, uschar **ptrs, int nptrs) | |
14aa5a05 | 128 | { |
d7978c0f JH |
129 | uschar *last_sub_start = str; |
130 | int n; | |
131 | ||
132 | for (n = 0; n < nptrs; n++) | |
133 | ptrs[n] = NULL; | |
134 | n = 1; | |
135 | ||
136 | while (*str) | |
c71c454d JH |
137 | if (*str++ == '\t') |
138 | if (n++ <= nptrs) | |
d7978c0f JH |
139 | { |
140 | *ptrs++ = last_sub_start; | |
c71c454d JH |
141 | last_sub_start = str; |
142 | str[-1] = '\0'; | |
d7978c0f | 143 | } |
d7978c0f JH |
144 | |
145 | /* It's acceptable for the string to end with a tab character. We see | |
146 | this in AUTH PLAIN without an initial response from the client, which | |
147 | causing us to send "334 " and get the data from the client. */ | |
148 | if (n <= nptrs) | |
c71c454d | 149 | *ptrs = last_sub_start; |
d7978c0f | 150 | else |
c71c454d JH |
151 | { |
152 | HDEBUG(D_auth) | |
153 | debug_printf("dovecot: warning: too many results from tab-splitting;" | |
154 | " saw %d fields, room for %d\n", n, nptrs); | |
155 | n = nptrs; | |
156 | } | |
d7978c0f JH |
157 | |
158 | return n <= nptrs ? n : nptrs; | |
3f1df0e3 | 159 | } |
14aa5a05 | 160 | |
3f1df0e3 PP |
161 | static void debug_strcut(uschar **ptrs, int nlen, int alen) ARG_UNUSED; |
162 | static void | |
163 | debug_strcut(uschar **ptrs, int nlen, int alen) | |
164 | { | |
d7978c0f JH |
165 | int i; |
166 | debug_printf("%d read but unreturned bytes; strcut() gave %d results: ", | |
167 | socket_buffer_left, nlen); | |
168 | for (i = 0; i < nlen; i++) | |
169 | debug_printf(" {%s}", ptrs[i]); | |
170 | if (nlen < alen) | |
171 | debug_printf(" last is %s\n", ptrs[i] ? ptrs[i] : US"<null>"); | |
172 | else | |
173 | debug_printf(" (max for capacity)\n"); | |
14aa5a05 PH |
174 | } |
175 | ||
176 | #define CHECK_COMMAND(str, arg_min, arg_max) do { \ | |
57c2c631 | 177 | if (strcmpic(US(str), args[0]) != 0) \ |
14aa5a05 PH |
178 | goto out; \ |
179 | if (nargs - 1 < (arg_min)) \ | |
180 | goto out; \ | |
6c588e74 | 181 | if ( (arg_max != -1) && (nargs - 1 > (arg_max)) ) \ |
14aa5a05 PH |
182 | goto out; \ |
183 | } while (0) | |
184 | ||
185 | #define OUT(msg) do { \ | |
186 | auth_defer_msg = (US msg); \ | |
187 | goto out; \ | |
188 | } while(0) | |
189 | ||
7befa435 PH |
190 | |
191 | ||
14aa5a05 | 192 | /************************************************* |
57c2c631 PH |
193 | * "fgets" to read directly from socket * |
194 | *************************************************/ | |
195 | ||
196 | /* Added by PH after a suggestion by Steve Usher because the previous use of | |
197 | C-style buffered I/O gave trouble. */ | |
198 | ||
199 | static uschar * | |
200 | dc_gets(uschar *s, int n, int fd) | |
201 | { | |
202 | int p = 0; | |
203 | int count = 0; | |
204 | ||
205 | for (;;) | |
206 | { | |
3f1df0e3 | 207 | if (socket_buffer_left == 0) |
57c2c631 | 208 | { |
c9f1be94 BL |
209 | if ((socket_buffer_left = read(fd, sbuffer, sizeof(sbuffer))) <= 0) |
210 | if (count == 0) return NULL; else break; | |
51473862 | 211 | p = 0; |
57c2c631 PH |
212 | } |
213 | ||
3f1df0e3 | 214 | while (p < socket_buffer_left) |
57c2c631 PH |
215 | { |
216 | if (count >= n - 1) break; | |
217 | s[count++] = sbuffer[p]; | |
218 | if (sbuffer[p++] == '\n') break; | |
219 | } | |
220 | ||
3f1df0e3 PP |
221 | memmove(sbuffer, sbuffer + p, socket_buffer_left - p); |
222 | socket_buffer_left -= p; | |
57c2c631 PH |
223 | |
224 | if (s[count-1] == '\n' || count >= n - 1) break; | |
225 | } | |
226 | ||
3f1df0e3 | 227 | s[count] = '\0'; |
57c2c631 PH |
228 | return s; |
229 | } | |
230 | ||
231 | ||
232 | ||
233 | ||
234 | /************************************************* | |
235 | * Server entry point * | |
236 | *************************************************/ | |
14aa5a05 | 237 | |
96f5fe4c JH |
238 | int |
239 | auth_dovecot_server(auth_instance * ablock, uschar * data) | |
14aa5a05 | 240 | { |
96f5fe4c JH |
241 | auth_dovecot_options_block *ob = |
242 | (auth_dovecot_options_block *) ablock->options_block; | |
243 | struct sockaddr_un sa; | |
244 | uschar buffer[DOVECOT_AUTH_MAXLINELEN]; | |
245 | uschar *args[DOVECOT_AUTH_MAXFIELDCOUNT]; | |
246 | uschar *auth_command; | |
247 | uschar *auth_extra_data = US""; | |
248 | uschar *p; | |
249 | int nargs, tmp; | |
77560253 | 250 | int crequid = 1, cont = 1, fd = -1, ret = DEFER; |
96f5fe4c JH |
251 | BOOL found = FALSE, have_mech_line = FALSE; |
252 | ||
253 | HDEBUG(D_auth) debug_printf("dovecot authentication\n"); | |
254 | ||
255 | if (!data) | |
256 | { | |
257 | ret = FAIL; | |
258 | goto out; | |
259 | } | |
14aa5a05 | 260 | |
96f5fe4c JH |
261 | memset(&sa, 0, sizeof(sa)); |
262 | sa.sun_family = AF_UNIX; | |
14aa5a05 | 263 | |
96f5fe4c JH |
264 | /* This was the original code here: it is nonsense because strncpy() |
265 | does not return an integer. I have converted this to use the function | |
266 | that formats and checks length. PH */ | |
14aa5a05 | 267 | |
96f5fe4c JH |
268 | /* |
269 | if (strncpy(sa.sun_path, ob->server_socket, sizeof(sa.sun_path)) < 0) { | |
270 | } | |
271 | */ | |
14aa5a05 | 272 | |
96f5fe4c JH |
273 | if (!string_format(US sa.sun_path, sizeof(sa.sun_path), "%s", |
274 | ob->server_socket)) | |
275 | { | |
276 | auth_defer_msg = US"authentication socket path too long"; | |
277 | return DEFER; | |
278 | } | |
7befa435 | 279 | |
96f5fe4c | 280 | auth_defer_msg = US"authentication socket connection error"; |
7befa435 | 281 | |
96f5fe4c JH |
282 | if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) |
283 | return DEFER; | |
7befa435 | 284 | |
96f5fe4c JH |
285 | if (connect(fd, (struct sockaddr *) &sa, sizeof(sa)) < 0) |
286 | goto out; | |
7befa435 | 287 | |
96f5fe4c | 288 | auth_defer_msg = US"authentication socket protocol error"; |
14aa5a05 | 289 | |
96f5fe4c JH |
290 | socket_buffer_left = 0; /* Global, used to read more than a line but return by line */ |
291 | while (cont) | |
292 | { | |
c71c454d | 293 | if (!dc_gets(buffer, sizeof(buffer), fd)) |
96f5fe4c JH |
294 | OUT("authentication socket read error or premature eof"); |
295 | p = buffer + Ustrlen(buffer) - 1; | |
296 | if (*p != '\n') | |
297 | OUT("authentication socket protocol line too long"); | |
298 | ||
299 | *p = '\0'; | |
300 | HDEBUG(D_auth) debug_printf("received: %s\n", buffer); | |
301 | ||
c71c454d | 302 | nargs = strcut(buffer, args, nelem(args)); |
96f5fe4c | 303 | |
c71c454d | 304 | /* HDEBUG(D_auth) debug_strcut(args, nargs, nelem(args)); */ |
96f5fe4c JH |
305 | |
306 | /* Code below rewritten by Kirill Miazine (km@krot.org). Only check commands that | |
307 | Exim will need. Original code also failed if Dovecot server sent unknown | |
308 | command. E.g. COOKIE in version 1.1 of the protocol would cause troubles. */ | |
309 | /* pdp: note that CUID is a per-connection identifier sent by the server, | |
310 | which increments at server discretion. | |
311 | By contrast, the "id" field of the protocol is a connection-specific request | |
312 | identifier, which needs to be unique per request from the client and is not | |
313 | connected to the CUID value, so we ignore CUID from server. It's purely for | |
314 | diagnostics. */ | |
315 | ||
316 | if (Ustrcmp(args[0], US"VERSION") == 0) | |
317 | { | |
318 | CHECK_COMMAND("VERSION", 2, 2); | |
319 | if (Uatoi(args[1]) != VERSION_MAJOR) | |
320 | OUT("authentication socket protocol version mismatch"); | |
321 | } | |
322 | else if (Ustrcmp(args[0], US"MECH") == 0) | |
323 | { | |
324 | CHECK_COMMAND("MECH", 1, INT_MAX); | |
325 | have_mech_line = TRUE; | |
326 | if (strcmpic(US args[1], ablock->public_name) == 0) | |
327 | found = TRUE; | |
328 | } | |
329 | else if (Ustrcmp(args[0], US"SPID") == 0) | |
330 | { | |
331 | /* Unfortunately the auth protocol handshake wasn't designed well | |
332 | to differentiate between auth-client/userdb/master. auth-userdb | |
333 | and auth-master send VERSION + SPID lines only and nothing | |
334 | afterwards, while auth-client sends VERSION + MECH + SPID + | |
335 | CUID + more. The simplest way that we can determine if we've | |
336 | connected to the correct socket is to see if MECH line exists or | |
337 | not (alternatively we'd have to have a small timeout after SPID | |
338 | to see if CUID is sent or not). */ | |
339 | ||
340 | if (!have_mech_line) | |
341 | OUT("authentication socket type mismatch" | |
342 | " (connected to auth-master instead of auth-client)"); | |
343 | } | |
344 | else if (Ustrcmp(args[0], US"DONE") == 0) | |
345 | { | |
346 | CHECK_COMMAND("DONE", 0, 0); | |
347 | cont = 0; | |
348 | } | |
349 | } | |
14aa5a05 | 350 | |
96f5fe4c JH |
351 | if (!found) |
352 | { | |
353 | auth_defer_msg = string_sprintf( | |
354 | "Dovecot did not advertise mechanism \"%s\" to us", ablock->public_name); | |
355 | goto out; | |
356 | } | |
14aa5a05 | 357 | |
96f5fe4c JH |
358 | /* Added by PH: data must not contain tab (as it is |
359 | b64 it shouldn't, but check for safety). */ | |
57c2c631 | 360 | |
96f5fe4c JH |
361 | if (Ustrchr(data, '\t') != NULL) |
362 | { | |
363 | ret = FAIL; | |
364 | goto out; | |
365 | } | |
14aa5a05 | 366 | |
96f5fe4c JH |
367 | /* Added by PH: extra fields when TLS is in use or if the TCP/IP |
368 | connection is local. */ | |
6c588e74 | 369 | |
c71c454d | 370 | if (tls_in.cipher) |
96f5fe4c | 371 | auth_extra_data = string_sprintf("secured\t%s%s", |
c71c454d JH |
372 | tls_in.certificate_verified ? "valid-client-cert" : "", |
373 | tls_in.certificate_verified ? "\t" : ""); | |
14aa5a05 | 374 | |
c71c454d | 375 | else if ( interface_address |
96f5fe4c JH |
376 | && Ustrcmp(sender_host_address, interface_address) == 0) |
377 | auth_extra_data = US"secured\t"; | |
14aa5a05 | 378 | |
14aa5a05 | 379 | |
96f5fe4c JH |
380 | /**************************************************************************** |
381 | The code below was the original code here. It didn't work. A reading of the | |
382 | file auth-protocol.txt.gz that came with Dovecot 1.0_beta8 indicated that | |
383 | this was not right. Maybe something changed. I changed it to move the | |
384 | service indication into the AUTH command, and it seems to be better. PH | |
385 | ||
386 | fprintf(f, "VERSION\t%d\t%d\r\nSERVICE\tSMTP\r\nCPID\t%d\r\n" | |
387 | "AUTH\t%d\t%s\trip=%s\tlip=%s\tresp=%s\r\n", | |
388 | VERSION_MAJOR, VERSION_MINOR, getpid(), cuid, | |
389 | ablock->public_name, sender_host_address, interface_address, | |
5903c6ff | 390 | data ? CS data : ""); |
96f5fe4c JH |
391 | |
392 | Subsequently, the command was modified to add "secured" and "valid-client- | |
393 | cert" when relevant. | |
394 | ****************************************************************************/ | |
14aa5a05 | 395 | |
96f5fe4c JH |
396 | auth_command = string_sprintf("VERSION\t%d\t%d\nCPID\t%d\n" |
397 | "AUTH\t%d\t%s\tservice=smtp\t%srip=%s\tlip=%s\tnologin\tresp=%s\n", | |
398 | VERSION_MAJOR, VERSION_MINOR, getpid(), crequid, | |
399 | ablock->public_name, auth_extra_data, sender_host_address, | |
400 | interface_address, data); | |
14aa5a05 | 401 | |
96f5fe4c JH |
402 | if (write(fd, auth_command, Ustrlen(auth_command)) < 0) |
403 | HDEBUG(D_auth) debug_printf("error sending auth_command: %s\n", | |
404 | strerror(errno)); | |
7befa435 | 405 | |
96f5fe4c | 406 | HDEBUG(D_auth) debug_printf("sent: %s", auth_command); |
7befa435 | 407 | |
96f5fe4c JH |
408 | while (1) |
409 | { | |
410 | uschar *temp; | |
411 | uschar *auth_id_pre = NULL; | |
14aa5a05 | 412 | |
c71c454d | 413 | if (!dc_gets(buffer, sizeof(buffer), fd)) |
96f5fe4c JH |
414 | { |
415 | auth_defer_msg = US"authentication socket read error or premature eof"; | |
416 | goto out; | |
417 | } | |
6c588e74 | 418 | |
96f5fe4c JH |
419 | buffer[Ustrlen(buffer) - 1] = 0; |
420 | HDEBUG(D_auth) debug_printf("received: %s\n", buffer); | |
c71c454d | 421 | nargs = strcut(buffer, args, nelem(args)); |
6c588e74 | 422 | |
96f5fe4c JH |
423 | if (Uatoi(args[1]) != crequid) |
424 | OUT("authentication socket connection id mismatch"); | |
14aa5a05 | 425 | |
96f5fe4c JH |
426 | switch (toupper(*args[0])) |
427 | { | |
428 | case 'C': | |
429 | CHECK_COMMAND("CONT", 1, 2); | |
430 | ||
431 | if ((tmp = auth_get_no64_data(&data, US args[2])) != OK) | |
432 | { | |
433 | ret = tmp; | |
434 | goto out; | |
435 | } | |
436 | ||
437 | /* Added by PH: data must not contain tab (as it is | |
438 | b64 it shouldn't, but check for safety). */ | |
439 | ||
440 | if (Ustrchr(data, '\t') != NULL) | |
441 | { | |
442 | ret = FAIL; | |
443 | goto out; | |
444 | } | |
445 | ||
446 | temp = string_sprintf("CONT\t%d\t%s\n", crequid, data); | |
447 | if (write(fd, temp, Ustrlen(temp)) < 0) | |
448 | OUT("authentication socket write error"); | |
449 | break; | |
450 | ||
451 | case 'F': | |
452 | CHECK_COMMAND("FAIL", 1, -1); | |
453 | ||
c71c454d JH |
454 | for (int i = 2; i < nargs && !auth_id_pre; i++) |
455 | if (Ustrncmp(args[i], US"user=", 5) == 0) | |
96f5fe4c | 456 | { |
c71c454d | 457 | auth_id_pre = args[i] + 5; |
96f5fe4c JH |
458 | expand_nstring[1] = auth_vars[0] = string_copy(auth_id_pre); /* PH */ |
459 | expand_nlength[1] = Ustrlen(auth_id_pre); | |
460 | expand_nmax = 1; | |
461 | } | |
96f5fe4c JH |
462 | ret = FAIL; |
463 | goto out; | |
464 | ||
465 | case 'O': | |
466 | CHECK_COMMAND("OK", 2, -1); | |
467 | ||
468 | /* Search for the "user=$USER" string in the args array | |
469 | and return the proper value. */ | |
470 | ||
c71c454d JH |
471 | for (int i = 2; i < nargs && !auth_id_pre; i++) |
472 | if (Ustrncmp(args[i], US"user=", 5) == 0) | |
96f5fe4c | 473 | { |
c71c454d | 474 | auth_id_pre = args[i] + 5; |
96f5fe4c JH |
475 | expand_nstring[1] = auth_vars[0] = string_copy(auth_id_pre); /* PH */ |
476 | expand_nlength[1] = Ustrlen(auth_id_pre); | |
477 | expand_nmax = 1; | |
478 | } | |
96f5fe4c | 479 | |
c71c454d | 480 | if (!auth_id_pre) |
96f5fe4c JH |
481 | OUT("authentication socket protocol error, username missing"); |
482 | ||
483 | ret = OK; | |
484 | /* fallthrough */ | |
485 | ||
486 | default: | |
487 | goto out; | |
488 | } | |
489 | } | |
14aa5a05 | 490 | |
57c2c631 | 491 | out: |
96f5fe4c JH |
492 | /* close the socket used by dovecot */ |
493 | if (fd >= 0) | |
494 | close(fd); | |
16ff981e | 495 | |
96f5fe4c JH |
496 | /* Expand server_condition as an authorization check */ |
497 | return ret == OK ? auth_check_serv_cond(ablock) : ret; | |
14aa5a05 | 498 | } |
d185889f JH |
499 | |
500 | ||
501 | #endif /*!MACRO_PREDEF*/ |