Commit | Line | Data |
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44bbabb5 PP |
1 | /************************************************* |
2 | * Exim - an Internet mail transport agent * | |
3 | *************************************************/ | |
4 | ||
f9ba5e22 | 5 | /* Copyright (c) University of Cambridge 1995 - 2018 */ |
44bbabb5 PP |
6 | /* See the file NOTICE for conditions of use and distribution. */ |
7 | ||
df6303fa PP |
8 | /* Copyright (c) Twitter Inc 2012 |
9 | Author: Phil Pennock <pdp@exim.org> */ | |
10 | /* Copyright (c) Phil Pennock 2012 */ | |
44bbabb5 PP |
11 | |
12 | /* Interface to GNU SASL library for generic authentication. */ | |
13 | ||
14 | /* Trade-offs: | |
15 | ||
16 | GNU SASL does not provide authentication data itself, so we have to expose | |
17 | that decision to configuration. For some mechanisms, we need to act much | |
18 | like plaintext. For others, we only need to be able to provide some | |
19 | evaluated data on demand. There's no abstracted way (ie, without hardcoding | |
20 | knowledge of authenticators here) to know which need what properties; we | |
21 | can't query a session or the library for "we will need these for mechanism X". | |
22 | ||
23 | So: we always require server_condition, even if sometimes it will just be | |
24 | set as "yes". We do provide a number of other hooks, which might not make | |
25 | sense in all contexts. For some, we can do checks at init time. | |
26 | */ | |
27 | ||
28 | #include "../exim.h" | |
29 | ||
30 | #ifndef AUTH_GSASL | |
31 | /* dummy function to satisfy compilers when we link in an "empty" file. */ | |
e1d15f5e JH |
32 | static void dummy(int x); |
33 | static void dummy2(int x) { dummy(x-1); } | |
d9d29e05 | 34 | static void dummy(int x) { dummy2(x-1); } |
44bbabb5 PP |
35 | #else |
36 | ||
37 | #include <gsasl.h> | |
38 | #include "gsasl_exim.h" | |
39 | ||
40 | /* Authenticator-specific options. */ | |
41 | /* I did have server_*_condition options for various mechanisms, but since | |
42 | we only ever handle one mechanism at a time, I didn't see the point in keeping | |
43 | that. In case someone sees a point, I've left the condition_check() API | |
44 | alone. */ | |
45 | optionlist auth_gsasl_options[] = { | |
46 | { "server_channelbinding", opt_bool, | |
47 | (void *)(offsetof(auth_gsasl_options_block, server_channelbinding)) }, | |
48 | { "server_hostname", opt_stringptr, | |
49 | (void *)(offsetof(auth_gsasl_options_block, server_hostname)) }, | |
50 | { "server_mech", opt_stringptr, | |
51 | (void *)(offsetof(auth_gsasl_options_block, server_mech)) }, | |
52 | { "server_password", opt_stringptr, | |
53 | (void *)(offsetof(auth_gsasl_options_block, server_password)) }, | |
54 | { "server_realm", opt_stringptr, | |
55 | (void *)(offsetof(auth_gsasl_options_block, server_realm)) }, | |
56 | { "server_scram_iter", opt_stringptr, | |
57 | (void *)(offsetof(auth_gsasl_options_block, server_scram_iter)) }, | |
58 | { "server_scram_salt", opt_stringptr, | |
59 | (void *)(offsetof(auth_gsasl_options_block, server_scram_salt)) }, | |
60 | { "server_service", opt_stringptr, | |
61 | (void *)(offsetof(auth_gsasl_options_block, server_service)) } | |
62 | }; | |
63 | /* GSASL_SCRAM_SALTED_PASSWORD documented only for client, so not implementing | |
64 | hooks to avoid cleartext passwords in the Exim server. */ | |
65 | ||
66 | int auth_gsasl_options_count = | |
67 | sizeof(auth_gsasl_options)/sizeof(optionlist); | |
68 | ||
69 | /* Defaults for the authenticator-specific options. */ | |
70 | auth_gsasl_options_block auth_gsasl_option_defaults = { | |
71 | US"smtp", /* server_service */ | |
72 | US"$primary_hostname", /* server_hostname */ | |
73 | NULL, /* server_realm */ | |
74 | NULL, /* server_mech */ | |
75 | NULL, /* server_password */ | |
76 | NULL, /* server_scram_iter */ | |
77 | NULL, /* server_scram_salt */ | |
78 | FALSE /* server_channelbinding */ | |
79 | }; | |
80 | ||
d185889f JH |
81 | |
82 | #ifdef MACRO_PREDEF | |
83 | ||
84 | /* Dummy values */ | |
85 | void auth_gsasl_init(auth_instance *ablock) {} | |
86 | int auth_gsasl_server(auth_instance *ablock, uschar *data) {return 0;} | |
d0858b27 | 87 | int auth_gsasl_client(auth_instance *ablock, smtp_inblock * sx, |
251b9eb4 | 88 | int timeout, uschar *buffer, int buffsize) {return 0;} |
f9df71c0 | 89 | void auth_gsasl_version_report(FILE *f) {} |
d185889f JH |
90 | |
91 | #else /*!MACRO_PREDEF*/ | |
92 | ||
93 | ||
94 | ||
44bbabb5 PP |
95 | /* "Globals" for managing the gsasl interface. */ |
96 | ||
97 | static Gsasl *gsasl_ctx = NULL; | |
98 | static int | |
99 | main_callback(Gsasl *ctx, Gsasl_session *sctx, Gsasl_property prop); | |
100 | static int | |
101 | server_callback(Gsasl *ctx, Gsasl_session *sctx, Gsasl_property prop, auth_instance *ablock); | |
102 | static int | |
103 | client_callback(Gsasl *ctx, Gsasl_session *sctx, Gsasl_property prop, auth_instance *ablock); | |
104 | ||
105 | static BOOL sasl_error_should_defer = FALSE; | |
106 | static Gsasl_property callback_loop = 0; | |
107 | static BOOL checked_server_condition = FALSE; | |
108 | ||
109 | enum { CURRENTLY_SERVER = 1, CURRENTLY_CLIENT = 2 }; | |
110 | ||
111 | struct callback_exim_state { | |
112 | auth_instance *ablock; | |
113 | int currently; | |
114 | }; | |
115 | ||
116 | ||
117 | /************************************************* | |
118 | * Initialization entry point * | |
119 | *************************************************/ | |
120 | ||
121 | /* Called for each instance, after its options have been read, to | |
122 | enable consistency checks to be done, or anything else that needs | |
123 | to be set up. */ | |
124 | ||
125 | void | |
126 | auth_gsasl_init(auth_instance *ablock) | |
127 | { | |
d7978c0f JH |
128 | char *p; |
129 | int rc, supported; | |
130 | auth_gsasl_options_block *ob = | |
131 | (auth_gsasl_options_block *)(ablock->options_block); | |
132 | ||
133 | /* As per existing Cyrus glue, use the authenticator's public name as | |
134 | the default for the mechanism name; we don't handle multiple mechanisms | |
135 | in one authenticator, but the same driver can be used multiple times. */ | |
136 | ||
6a2c32cb | 137 | if (!ob->server_mech) |
d7978c0f JH |
138 | ob->server_mech = string_copy(ablock->public_name); |
139 | ||
140 | /* Can get multiple session contexts from one library context, so just | |
141 | initialise the once. */ | |
6a2c32cb JH |
142 | |
143 | if (!gsasl_ctx) | |
144 | { | |
145 | if ((rc = gsasl_init(&gsasl_ctx)) != GSASL_OK) | |
d7978c0f JH |
146 | log_write(0, LOG_PANIC_DIE|LOG_CONFIG_FOR, "%s authenticator: " |
147 | "couldn't initialise GNU SASL library: %s (%s)", | |
148 | ablock->name, gsasl_strerror_name(rc), gsasl_strerror(rc)); | |
6a2c32cb | 149 | |
d7978c0f | 150 | gsasl_callback_set(gsasl_ctx, main_callback); |
6a2c32cb | 151 | } |
44bbabb5 | 152 | |
d7978c0f | 153 | /* We don't need this except to log it for debugging. */ |
6a2c32cb JH |
154 | |
155 | if ((rc = gsasl_server_mechlist(gsasl_ctx, &p)) != GSASL_OK) | |
d7978c0f JH |
156 | log_write(0, LOG_PANIC_DIE|LOG_CONFIG_FOR, "%s authenticator: " |
157 | "failed to retrieve list of mechanisms: %s (%s)", | |
158 | ablock->name, gsasl_strerror_name(rc), gsasl_strerror(rc)); | |
6a2c32cb | 159 | |
d7978c0f | 160 | HDEBUG(D_auth) debug_printf("GNU SASL supports: %s\n", p); |
44bbabb5 | 161 | |
d7978c0f JH |
162 | supported = gsasl_client_support_p(gsasl_ctx, CCS ob->server_mech); |
163 | if (!supported) | |
164 | log_write(0, LOG_PANIC_DIE|LOG_CONFIG_FOR, "%s authenticator: " | |
165 | "GNU SASL does not support mechanism \"%s\"", | |
166 | ablock->name, ob->server_mech); | |
167 | ||
6a2c32cb JH |
168 | if ( !ablock->server_condition |
169 | && ( streqic(ob->server_mech, US"EXTERNAL") | |
170 | || streqic(ob->server_mech, US"ANONYMOUS") | |
171 | || streqic(ob->server_mech, US"PLAIN") | |
172 | || streqic(ob->server_mech, US"LOGIN") | |
173 | ) ) | |
d7978c0f JH |
174 | log_write(0, LOG_PANIC_DIE|LOG_CONFIG_FOR, "%s authenticator: " |
175 | "Need server_condition for %s mechanism", | |
176 | ablock->name, ob->server_mech); | |
44bbabb5 | 177 | |
d7978c0f JH |
178 | /* This does *not* scale to new SASL mechanisms. Need a better way to ask |
179 | which properties will be needed. */ | |
6a2c32cb JH |
180 | |
181 | if ( !ob->server_realm | |
182 | && streqic(ob->server_mech, US"DIGEST-MD5")) | |
d7978c0f JH |
183 | log_write(0, LOG_PANIC_DIE|LOG_CONFIG_FOR, "%s authenticator: " |
184 | "Need server_realm for %s mechanism", | |
185 | ablock->name, ob->server_mech); | |
ce52b325 | 186 | |
d7978c0f JH |
187 | /* At present, for mechanisms we don't panic on absence of server_condition; |
188 | need to figure out the most generically correct approach to deciding when | |
189 | it's critical and when it isn't. Eg, for simple validation (PLAIN mechanism, | |
190 | etc) it clearly is critical. | |
44bbabb5 | 191 | |
d7978c0f JH |
192 | So don't activate without server_condition, this might be relaxed in the future. |
193 | */ | |
6a2c32cb JH |
194 | |
195 | if (ablock->server_condition) ablock->server = TRUE; | |
d7978c0f | 196 | ablock->client = FALSE; |
44bbabb5 PP |
197 | } |
198 | ||
199 | ||
200 | /* GNU SASL uses one top-level callback, registered at library level. | |
201 | We dispatch to client and server functions instead. */ | |
202 | ||
203 | static int | |
204 | main_callback(Gsasl *ctx, Gsasl_session *sctx, Gsasl_property prop) | |
205 | { | |
d7978c0f JH |
206 | int rc = 0; |
207 | struct callback_exim_state *cb_state = | |
208 | (struct callback_exim_state *)gsasl_session_hook_get(sctx); | |
209 | ||
210 | HDEBUG(D_auth) | |
211 | debug_printf("GNU SASL Callback entered, prop=%d (loop prop=%d)\n", | |
212 | prop, callback_loop); | |
213 | ||
6a2c32cb | 214 | if (!cb_state) |
d7978c0f JH |
215 | { |
216 | HDEBUG(D_auth) debug_printf(" not from our server/client processing.\n"); | |
217 | return GSASL_NO_CALLBACK; | |
44bbabb5 PP |
218 | } |
219 | ||
d7978c0f JH |
220 | if (callback_loop > 0) |
221 | { | |
222 | /* Most likely is that we were asked for property foo, and to | |
223 | expand the string we asked for property bar to put into an auth | |
224 | variable, but property bar is not supplied for this mechanism. */ | |
225 | HDEBUG(D_auth) | |
226 | debug_printf("Loop, asked for property %d while handling property %d\n", | |
227 | prop, callback_loop); | |
228 | return GSASL_NO_CALLBACK; | |
44bbabb5 | 229 | } |
d7978c0f | 230 | callback_loop = prop; |
44bbabb5 | 231 | |
d7978c0f JH |
232 | if (cb_state->currently == CURRENTLY_CLIENT) |
233 | rc = client_callback(ctx, sctx, prop, cb_state->ablock); | |
234 | else if (cb_state->currently == CURRENTLY_SERVER) | |
235 | rc = server_callback(ctx, sctx, prop, cb_state->ablock); | |
236 | else | |
237 | log_write(0, LOG_PANIC_DIE|LOG_CONFIG_FOR, "%s authenticator: " | |
238 | "unhandled callback state, bug in Exim", cb_state->ablock->name); | |
239 | /* NOTREACHED */ | |
44bbabb5 | 240 | |
d7978c0f JH |
241 | callback_loop = 0; |
242 | return rc; | |
44bbabb5 PP |
243 | } |
244 | ||
245 | ||
246 | /************************************************* | |
247 | * Server entry point * | |
248 | *************************************************/ | |
249 | ||
250 | /* For interface, see auths/README */ | |
251 | ||
252 | int | |
253 | auth_gsasl_server(auth_instance *ablock, uschar *initial_data) | |
254 | { | |
d7978c0f JH |
255 | char *tmps; |
256 | char *to_send, *received; | |
257 | Gsasl_session *sctx = NULL; | |
258 | auth_gsasl_options_block *ob = | |
259 | (auth_gsasl_options_block *)(ablock->options_block); | |
260 | struct callback_exim_state cb_state; | |
261 | int rc, auth_result, exim_error, exim_error_override; | |
262 | ||
263 | HDEBUG(D_auth) | |
264 | debug_printf("GNU SASL: initialising session for %s, mechanism %s.\n", | |
265 | ablock->name, ob->server_mech); | |
266 | ||
6a2c32cb | 267 | if ((rc = gsasl_server_start(gsasl_ctx, CCS ob->server_mech, &sctx)) != GSASL_OK) |
d7978c0f JH |
268 | { |
269 | auth_defer_msg = string_sprintf("GNU SASL: session start failure: %s (%s)", | |
270 | gsasl_strerror_name(rc), gsasl_strerror(rc)); | |
271 | HDEBUG(D_auth) debug_printf("%s\n", auth_defer_msg); | |
272 | return DEFER; | |
44bbabb5 | 273 | } |
d7978c0f JH |
274 | /* Hereafter: gsasl_finish(sctx) please */ |
275 | ||
276 | gsasl_session_hook_set(sctx, (void *)ablock); | |
277 | cb_state.ablock = ablock; | |
278 | cb_state.currently = CURRENTLY_SERVER; | |
279 | gsasl_session_hook_set(sctx, (void *)&cb_state); | |
280 | ||
281 | tmps = CS expand_string(ob->server_service); | |
282 | gsasl_property_set(sctx, GSASL_SERVICE, tmps); | |
283 | tmps = CS expand_string(ob->server_hostname); | |
284 | gsasl_property_set(sctx, GSASL_HOSTNAME, tmps); | |
285 | if (ob->server_realm) | |
286 | { | |
287 | tmps = CS expand_string(ob->server_realm); | |
288 | if (tmps && *tmps) | |
289 | gsasl_property_set(sctx, GSASL_REALM, tmps); | |
44bbabb5 | 290 | } |
d7978c0f JH |
291 | /* We don't support protection layers. */ |
292 | gsasl_property_set(sctx, GSASL_QOPS, "qop-auth"); | |
6a2c32cb | 293 | |
01603eec | 294 | #ifndef DISABLE_TLS |
d7978c0f JH |
295 | if (tls_channelbinding_b64) |
296 | { | |
297 | /* Some auth mechanisms can ensure that both sides are talking withing the | |
298 | same security context; for TLS, this means that even if a bad certificate | |
299 | has been accepted, they remain MitM-proof because both sides must be within | |
300 | the same negotiated session; if someone is terminating one session and | |
301 | proxying data on within a second, authentication will fail. | |
302 | ||
303 | We might not have this available, depending upon TLS implementation, | |
304 | ciphersuite, phase of moon ... | |
305 | ||
306 | If we do, it results in extra SASL mechanisms being available; here, | |
307 | Exim's one-mechanism-per-authenticator potentially causes problems. | |
308 | It depends upon how GNU SASL will implement the PLUS variants of GS2 | |
309 | and whether it automatically mandates a switch to the bound PLUS | |
310 | if the data is available. Since default-on, despite being more secure, | |
311 | would then result in mechanism name changes on a library update, we | |
312 | have little choice but to default it off and let the admin choose to | |
313 | enable it. *sigh* | |
314 | */ | |
315 | if (ob->server_channelbinding) | |
316 | { | |
317 | HDEBUG(D_auth) debug_printf("Auth %s: Enabling channel-binding\n", | |
318 | ablock->name); | |
319 | gsasl_property_set(sctx, GSASL_CB_TLS_UNIQUE, | |
320 | CCS tls_channelbinding_b64); | |
44bbabb5 | 321 | } |
d7978c0f | 322 | else |
44bbabb5 | 323 | HDEBUG(D_auth) |
d7978c0f JH |
324 | debug_printf("Auth %s: Not enabling channel-binding (data available)\n", |
325 | ablock->name); | |
44bbabb5 | 326 | } |
d7978c0f JH |
327 | else |
328 | HDEBUG(D_auth) | |
329 | debug_printf("Auth %s: no channel-binding data available\n", | |
330 | ablock->name); | |
44bbabb5 PP |
331 | #endif |
332 | ||
d7978c0f JH |
333 | checked_server_condition = FALSE; |
334 | ||
335 | received = CS initial_data; | |
336 | to_send = NULL; | |
337 | exim_error = exim_error_override = OK; | |
338 | ||
339 | do { | |
6a2c32cb | 340 | switch (rc = gsasl_step64(sctx, received, &to_send)) |
d7978c0f JH |
341 | { |
342 | case GSASL_OK: | |
343 | if (!to_send) | |
344 | goto STOP_INTERACTION; | |
345 | break; | |
346 | ||
347 | case GSASL_NEEDS_MORE: | |
348 | break; | |
349 | ||
350 | case GSASL_AUTHENTICATION_ERROR: | |
351 | case GSASL_INTEGRITY_ERROR: | |
352 | case GSASL_NO_AUTHID: | |
353 | case GSASL_NO_ANONYMOUS_TOKEN: | |
354 | case GSASL_NO_AUTHZID: | |
355 | case GSASL_NO_PASSWORD: | |
356 | case GSASL_NO_PASSCODE: | |
357 | case GSASL_NO_PIN: | |
358 | case GSASL_BASE64_ERROR: | |
359 | HDEBUG(D_auth) debug_printf("GNU SASL permanent error: %s (%s)\n", | |
360 | gsasl_strerror_name(rc), gsasl_strerror(rc)); | |
361 | log_write(0, LOG_REJECT, "%s authenticator (%s):\n " | |
362 | "GNU SASL permanent failure: %s (%s)", | |
363 | ablock->name, ob->server_mech, | |
364 | gsasl_strerror_name(rc), gsasl_strerror(rc)); | |
365 | if (rc == GSASL_BASE64_ERROR) | |
366 | exim_error_override = BAD64; | |
367 | goto STOP_INTERACTION; | |
368 | ||
369 | default: | |
370 | auth_defer_msg = string_sprintf("GNU SASL temporary error: %s (%s)", | |
371 | gsasl_strerror_name(rc), gsasl_strerror(rc)); | |
372 | HDEBUG(D_auth) debug_printf("%s\n", auth_defer_msg); | |
373 | exim_error_override = DEFER; | |
374 | goto STOP_INTERACTION; | |
44bbabb5 PP |
375 | } |
376 | ||
6a2c32cb JH |
377 | if ((rc == GSASL_NEEDS_MORE) || (to_send && *to_send)) |
378 | exim_error = auth_get_no64_data((uschar **)&received, US to_send); | |
ce52b325 | 379 | |
d7978c0f JH |
380 | if (to_send) |
381 | { | |
382 | free(to_send); | |
383 | to_send = NULL; | |
ce52b325 PP |
384 | } |
385 | ||
d7978c0f JH |
386 | if (exim_error) |
387 | break; /* handles * cancelled check */ | |
44bbabb5 PP |
388 | |
389 | } while (rc == GSASL_NEEDS_MORE); | |
390 | ||
391 | STOP_INTERACTION: | |
d7978c0f | 392 | auth_result = rc; |
44bbabb5 | 393 | |
d7978c0f | 394 | gsasl_finish(sctx); |
44bbabb5 | 395 | |
d7978c0f | 396 | /* Can return: OK DEFER FAIL CANCELLED BAD64 UNEXPECTED */ |
44bbabb5 | 397 | |
d7978c0f JH |
398 | if (exim_error != OK) |
399 | return exim_error; | |
44bbabb5 | 400 | |
d7978c0f JH |
401 | if (auth_result != GSASL_OK) |
402 | { | |
403 | HDEBUG(D_auth) debug_printf("authentication returned %s (%s)\n", | |
404 | gsasl_strerror_name(auth_result), gsasl_strerror(auth_result)); | |
405 | if (exim_error_override != OK) | |
406 | return exim_error_override; /* might be DEFER */ | |
407 | if (sasl_error_should_defer) /* overriding auth failure SASL error */ | |
408 | return DEFER; | |
409 | return FAIL; | |
44bbabb5 PP |
410 | } |
411 | ||
d7978c0f JH |
412 | /* Auth succeeded, check server_condition unless already done in callback */ |
413 | return checked_server_condition ? OK : auth_check_serv_cond(ablock); | |
44bbabb5 PP |
414 | } |
415 | ||
d7978c0f | 416 | |
44bbabb5 PP |
417 | /* returns the GSASL status of expanding the Exim string given */ |
418 | static int | |
419 | condition_check(auth_instance *ablock, uschar *label, uschar *condition_string) | |
420 | { | |
6a2c32cb JH |
421 | int exim_rc = auth_check_some_cond(ablock, label, condition_string, FAIL); |
422 | switch (exim_rc) | |
d7978c0f | 423 | { |
6a2c32cb JH |
424 | case OK: return GSASL_OK; |
425 | case DEFER: sasl_error_should_defer = TRUE; | |
426 | return GSASL_AUTHENTICATION_ERROR; | |
427 | case FAIL: return GSASL_AUTHENTICATION_ERROR; | |
428 | default: log_write(0, LOG_PANIC_DIE|LOG_CONFIG_FOR, "%s authenticator: " | |
429 | "Unhandled return from checking %s: %d", | |
430 | ablock->name, label, exim_rc); | |
44bbabb5 | 431 | } |
d7978c0f | 432 | |
d7978c0f JH |
433 | /* NOTREACHED */ |
434 | return GSASL_AUTHENTICATION_ERROR; | |
44bbabb5 PP |
435 | } |
436 | ||
437 | static int | |
6a2c32cb JH |
438 | server_callback(Gsasl *ctx, Gsasl_session *sctx, Gsasl_property prop, |
439 | auth_instance *ablock) | |
44bbabb5 | 440 | { |
d7978c0f JH |
441 | char *tmps; |
442 | uschar *propval; | |
443 | int cbrc = GSASL_NO_CALLBACK; | |
444 | auth_gsasl_options_block *ob = | |
445 | (auth_gsasl_options_block *)(ablock->options_block); | |
446 | ||
447 | HDEBUG(D_auth) | |
448 | debug_printf("GNU SASL callback %d for %s/%s as server\n", | |
449 | prop, ablock->name, ablock->public_name); | |
450 | ||
451 | for (int i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; | |
452 | expand_nmax = 0; | |
453 | ||
454 | switch (prop) | |
455 | { | |
456 | case GSASL_VALIDATE_SIMPLE: | |
457 | /* GSASL_AUTHID, GSASL_AUTHZID, and GSASL_PASSWORD */ | |
458 | propval = US gsasl_property_fast(sctx, GSASL_AUTHID); | |
459 | auth_vars[0] = expand_nstring[1] = propval ? propval : US""; | |
460 | propval = US gsasl_property_fast(sctx, GSASL_AUTHZID); | |
461 | auth_vars[1] = expand_nstring[2] = propval ? propval : US""; | |
462 | propval = US gsasl_property_fast(sctx, GSASL_PASSWORD); | |
463 | auth_vars[2] = expand_nstring[3] = propval ? propval : US""; | |
464 | expand_nmax = 3; | |
465 | for (int i = 1; i <= 3; ++i) | |
466 | expand_nlength[i] = Ustrlen(expand_nstring[i]); | |
467 | ||
468 | cbrc = condition_check(ablock, US"server_condition", ablock->server_condition); | |
469 | checked_server_condition = TRUE; | |
470 | break; | |
471 | ||
472 | case GSASL_VALIDATE_EXTERNAL: | |
6a2c32cb | 473 | if (!ablock->server_condition) |
d7978c0f JH |
474 | { |
475 | HDEBUG(D_auth) debug_printf("No server_condition supplied, to validate EXTERNAL.\n"); | |
476 | cbrc = GSASL_AUTHENTICATION_ERROR; | |
44bbabb5 | 477 | break; |
44bbabb5 | 478 | } |
d7978c0f | 479 | propval = US gsasl_property_fast(sctx, GSASL_AUTHZID); |
6a2c32cb | 480 | |
d7978c0f JH |
481 | /* We always set $auth1, even if only to empty string. */ |
482 | auth_vars[0] = expand_nstring[1] = propval ? propval : US""; | |
483 | expand_nlength[1] = Ustrlen(expand_nstring[1]); | |
484 | expand_nmax = 1; | |
485 | ||
486 | cbrc = condition_check(ablock, | |
487 | US"server_condition (EXTERNAL)", ablock->server_condition); | |
488 | checked_server_condition = TRUE; | |
489 | break; | |
490 | ||
491 | case GSASL_VALIDATE_ANONYMOUS: | |
6a2c32cb | 492 | if (!ablock->server_condition) |
d7978c0f JH |
493 | { |
494 | HDEBUG(D_auth) debug_printf("No server_condition supplied, to validate ANONYMOUS.\n"); | |
495 | cbrc = GSASL_AUTHENTICATION_ERROR; | |
44bbabb5 | 496 | break; |
44bbabb5 | 497 | } |
d7978c0f | 498 | propval = US gsasl_property_fast(sctx, GSASL_ANONYMOUS_TOKEN); |
6a2c32cb | 499 | |
d7978c0f | 500 | /* We always set $auth1, even if only to empty string. */ |
6a2c32cb | 501 | |
d7978c0f JH |
502 | auth_vars[0] = expand_nstring[1] = propval ? propval : US""; |
503 | expand_nlength[1] = Ustrlen(expand_nstring[1]); | |
504 | expand_nmax = 1; | |
505 | ||
506 | cbrc = condition_check(ablock, | |
507 | US"server_condition (ANONYMOUS)", ablock->server_condition); | |
508 | checked_server_condition = TRUE; | |
509 | break; | |
510 | ||
511 | case GSASL_VALIDATE_GSSAPI: | |
512 | /* GSASL_AUTHZID and GSASL_GSSAPI_DISPLAY_NAME | |
513 | The display-name is authenticated as part of GSS, the authzid is claimed | |
514 | by the SASL integration after authentication; protected against tampering | |
515 | (if the SASL mechanism supports that, which Kerberos does) but is | |
516 | unverified, same as normal for other mechanisms. | |
6a2c32cb | 517 | First coding, we had these values swapped, but for consistency and prior |
d7978c0f JH |
518 | to the first release of Exim with this authenticator, they've been |
519 | switched to match the ordering of GSASL_VALIDATE_SIMPLE. */ | |
6a2c32cb | 520 | |
d7978c0f JH |
521 | propval = US gsasl_property_fast(sctx, GSASL_GSSAPI_DISPLAY_NAME); |
522 | auth_vars[0] = expand_nstring[1] = propval ? propval : US""; | |
523 | propval = US gsasl_property_fast(sctx, GSASL_AUTHZID); | |
524 | auth_vars[1] = expand_nstring[2] = propval ? propval : US""; | |
525 | expand_nmax = 2; | |
526 | for (int i = 1; i <= 2; ++i) | |
527 | expand_nlength[i] = Ustrlen(expand_nstring[i]); | |
528 | ||
529 | /* In this one case, it perhaps makes sense to default back open? | |
530 | But for consistency, let's just mandate server_condition here too. */ | |
6a2c32cb | 531 | |
d7978c0f JH |
532 | cbrc = condition_check(ablock, |
533 | US"server_condition (GSSAPI family)", ablock->server_condition); | |
534 | checked_server_condition = TRUE; | |
535 | break; | |
536 | ||
537 | case GSASL_PASSWORD: | |
538 | /* DIGEST-MD5: GSASL_AUTHID, GSASL_AUTHZID and GSASL_REALM | |
539 | CRAM-MD5: GSASL_AUTHID | |
540 | PLAIN: GSASL_AUTHID and GSASL_AUTHZID | |
541 | LOGIN: GSASL_AUTHID | |
542 | */ | |
543 | if (ob->server_scram_iter) | |
544 | { | |
545 | tmps = CS expand_string(ob->server_scram_iter); | |
546 | gsasl_property_set(sctx, GSASL_SCRAM_ITER, tmps); | |
44bbabb5 | 547 | } |
d7978c0f JH |
548 | if (ob->server_scram_salt) |
549 | { | |
550 | tmps = CS expand_string(ob->server_scram_salt); | |
551 | gsasl_property_set(sctx, GSASL_SCRAM_SALT, tmps); | |
44bbabb5 | 552 | } |
6a2c32cb | 553 | |
d7978c0f JH |
554 | /* Asking for GSASL_AUTHZID calls back into us if we use |
555 | gsasl_property_get(), thus the use of gsasl_property_fast(). | |
556 | Do we really want to hardcode limits per mechanism? What happens when | |
557 | a new mechanism is added to the library. It *shouldn't* result in us | |
558 | needing to add more glue, since avoiding that is a large part of the | |
559 | point of SASL. */ | |
6a2c32cb | 560 | |
d7978c0f JH |
561 | propval = US gsasl_property_fast(sctx, GSASL_AUTHID); |
562 | auth_vars[0] = expand_nstring[1] = propval ? propval : US""; | |
563 | propval = US gsasl_property_fast(sctx, GSASL_AUTHZID); | |
564 | auth_vars[1] = expand_nstring[2] = propval ? propval : US""; | |
565 | propval = US gsasl_property_fast(sctx, GSASL_REALM); | |
566 | auth_vars[2] = expand_nstring[3] = propval ? propval : US""; | |
567 | expand_nmax = 3; | |
568 | for (int i = 1; i <= 3; ++i) | |
569 | expand_nlength[i] = Ustrlen(expand_nstring[i]); | |
570 | ||
6a2c32cb | 571 | if (!(tmps = CS expand_string(ob->server_password))) |
d7978c0f JH |
572 | { |
573 | sasl_error_should_defer = f.expand_string_forcedfail ? FALSE : TRUE; | |
574 | HDEBUG(D_auth) debug_printf("server_password expansion failed, so " | |
575 | "can't tell GNU SASL library the password for %s\n", auth_vars[0]); | |
576 | return GSASL_AUTHENTICATION_ERROR; | |
44bbabb5 | 577 | } |
d7978c0f | 578 | gsasl_property_set(sctx, GSASL_PASSWORD, tmps); |
6a2c32cb | 579 | |
d7978c0f JH |
580 | /* This is inadequate; don't think Exim's store stacks are geared |
581 | for memory wiping, so expanding strings will leave stuff laying around. | |
582 | But no need to compound the problem, so get rid of the one we can. */ | |
6a2c32cb | 583 | |
d7978c0f JH |
584 | memset(tmps, '\0', strlen(tmps)); |
585 | cbrc = GSASL_OK; | |
586 | break; | |
587 | ||
588 | default: | |
589 | HDEBUG(D_auth) debug_printf("Unrecognised callback: %d\n", prop); | |
590 | cbrc = GSASL_NO_CALLBACK; | |
44bbabb5 PP |
591 | } |
592 | ||
d7978c0f JH |
593 | HDEBUG(D_auth) debug_printf("Returning %s (%s)\n", |
594 | gsasl_strerror_name(cbrc), gsasl_strerror(cbrc)); | |
44bbabb5 | 595 | |
d7978c0f | 596 | return cbrc; |
44bbabb5 PP |
597 | } |
598 | ||
599 | ||
600 | /************************************************* | |
601 | * Client entry point * | |
602 | *************************************************/ | |
603 | ||
604 | /* For interface, see auths/README */ | |
605 | ||
606 | int | |
607 | auth_gsasl_client( | |
d0858b27 JH |
608 | auth_instance *ablock, /* authenticator block */ |
609 | smtp_inblock * sx, /* connection */ | |
610 | int timeout, /* command timeout */ | |
611 | uschar *buffer, /* buffer for reading response */ | |
612 | int buffsize) /* size of buffer */ | |
44bbabb5 | 613 | { |
d7978c0f JH |
614 | HDEBUG(D_auth) |
615 | debug_printf("Client side NOT IMPLEMENTED: you should not see this!\n"); | |
616 | /* NOT IMPLEMENTED */ | |
617 | return FAIL; | |
44bbabb5 PP |
618 | } |
619 | ||
620 | static int | |
621 | client_callback(Gsasl *ctx, Gsasl_session *sctx, Gsasl_property prop, auth_instance *ablock) | |
622 | { | |
d7978c0f JH |
623 | int cbrc = GSASL_NO_CALLBACK; |
624 | HDEBUG(D_auth) | |
625 | debug_printf("GNU SASL callback %d for %s/%s as client\n", | |
626 | prop, ablock->name, ablock->public_name); | |
44bbabb5 | 627 | |
d7978c0f JH |
628 | HDEBUG(D_auth) |
629 | debug_printf("Client side NOT IMPLEMENTED: you should not see this!\n"); | |
44bbabb5 | 630 | |
d7978c0f | 631 | return cbrc; |
44bbabb5 PP |
632 | } |
633 | ||
634 | /************************************************* | |
635 | * Diagnostic API * | |
636 | *************************************************/ | |
637 | ||
638 | void | |
639 | auth_gsasl_version_report(FILE *f) | |
640 | { | |
d7978c0f JH |
641 | const char *runtime; |
642 | runtime = gsasl_check_version(NULL); | |
643 | fprintf(f, "Library version: GNU SASL: Compile: %s\n" | |
644 | " Runtime: %s\n", | |
645 | GSASL_VERSION, runtime); | |
44bbabb5 PP |
646 | } |
647 | ||
d185889f | 648 | #endif /*!MACRO_PREDEF*/ |
44bbabb5 PP |
649 | #endif /* AUTH_GSASL */ |
650 | ||
651 | /* End of gsasl_exim.c */ |