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0756eb3c PH |
1 | /************************************************* |
2 | * Exim - an Internet mail transport agent * | |
3 | *************************************************/ | |
4 | ||
0a49a7a4 | 5 | /* Copyright (c) University of Cambridge 1995 - 2009 */ |
0756eb3c PH |
6 | /* See the file NOTICE for conditions of use and distribution. */ |
7 | ||
c5ddb310 | 8 | /* This code was originally contributed by Matthew Byng-Maddick */ |
0756eb3c PH |
9 | |
10 | /* Copyright (c) A L Digital 2004 */ | |
11 | ||
12 | /* A generic (mechanism independent) Cyrus SASL authenticator. */ | |
13 | ||
14 | ||
15 | #include "../exim.h" | |
16 | ||
17 | ||
18 | /* We can't just compile this code and allow the library mechanism to omit the | |
19 | functions if they are not wanted, because we need to have the Cyrus SASL header | |
20 | available for compiling. Therefore, compile these functions only if | |
21 | AUTH_CYRUS_SASL is defined. However, some compilers don't like compiling empty | |
22 | modules, so keep them happy with a dummy when skipping the rest. Make it | |
23 | reference itself to stop picky compilers complaining that it is unused, and put | |
24 | in a dummy argument to stop even pickier compilers complaining about infinite | |
25 | loops. */ | |
26 | ||
27 | #ifndef AUTH_CYRUS_SASL | |
28 | static void dummy(int x) { dummy(x-1); } | |
29 | #else | |
30 | ||
31 | ||
32 | #include <sasl/sasl.h> | |
33 | #include "cyrus_sasl.h" | |
34 | ||
35 | /* Options specific to the cyrus_sasl authentication mechanism. */ | |
36 | ||
37 | optionlist auth_cyrus_sasl_options[] = { | |
38 | { "server_hostname", opt_stringptr, | |
39 | (void *)(offsetof(auth_cyrus_sasl_options_block, server_hostname)) }, | |
40 | { "server_mech", opt_stringptr, | |
41 | (void *)(offsetof(auth_cyrus_sasl_options_block, server_mech)) }, | |
42 | { "server_realm", opt_stringptr, | |
43 | (void *)(offsetof(auth_cyrus_sasl_options_block, server_realm)) }, | |
44 | { "server_service", opt_stringptr, | |
45 | (void *)(offsetof(auth_cyrus_sasl_options_block, server_service)) } | |
46 | }; | |
47 | ||
48 | /* Size of the options list. An extern variable has to be used so that its | |
49 | address can appear in the tables drtables.c. */ | |
50 | ||
51 | int auth_cyrus_sasl_options_count = | |
52 | sizeof(auth_cyrus_sasl_options)/sizeof(optionlist); | |
53 | ||
16ff981e | 54 | /* Default private options block for the cyrus_sasl authentication method. */ |
0756eb3c PH |
55 | |
56 | auth_cyrus_sasl_options_block auth_cyrus_sasl_option_defaults = { | |
57 | US"smtp", /* server_service */ | |
58 | US"$primary_hostname", /* server_hostname */ | |
59 | NULL, /* server_realm */ | |
60 | NULL /* server_mech */ | |
61 | }; | |
62 | ||
63 | ||
64 | /************************************************* | |
65 | * Initialization entry point * | |
66 | *************************************************/ | |
67 | ||
68 | /* Called for each instance, after its options have been read, to | |
69 | enable consistency checks to be done, or anything else that needs | |
70 | to be set up. */ | |
71 | ||
c5ddb310 PH |
72 | |
73 | /* Auxiliary function, passed in data to sasl_server_init(). */ | |
74 | ||
75 | static int | |
76 | mysasl_config(void *context, | |
77 | const char *plugin_name, | |
78 | const char *option, | |
79 | const char **result, | |
80 | unsigned int *len) | |
81 | { | |
82 | if (context && !strcmp(option, "mech_list")) | |
83 | { | |
84 | *result = context; | |
85 | if (len != NULL) *len = strlen(*result); | |
86 | return SASL_OK; | |
87 | } | |
88 | return SASL_FAIL; | |
89 | } | |
90 | ||
91 | /* Here's the real function */ | |
92 | ||
0756eb3c PH |
93 | void |
94 | auth_cyrus_sasl_init(auth_instance *ablock) | |
95 | { | |
96 | auth_cyrus_sasl_options_block *ob = | |
97 | (auth_cyrus_sasl_options_block *)(ablock->options_block); | |
0756eb3c PH |
98 | uschar *list, *listptr, *buffer; |
99 | int rc, i; | |
100 | unsigned int len; | |
101 | uschar *rs_point; | |
102 | ||
c5ddb310 PH |
103 | sasl_conn_t *conn; |
104 | sasl_callback_t cbs[]={ | |
105 | {SASL_CB_GETOPT, NULL, NULL }, | |
106 | {SASL_CB_LIST_END, NULL, NULL}}; | |
107 | ||
0756eb3c PH |
108 | /* default the mechanism to our "public name" */ |
109 | if(ob->server_mech == NULL) | |
110 | ob->server_mech=string_copy(ablock->public_name); | |
111 | ||
112 | /* we're going to initialise the library to check that there is an | |
113 | * authenticator of type whatever mechanism we're using | |
114 | */ | |
c5ddb310 PH |
115 | |
116 | cbs[0].proc = &mysasl_config; | |
117 | cbs[0].context = ob->server_mech; | |
118 | ||
0756eb3c | 119 | rc=sasl_server_init(cbs, "exim"); |
c5ddb310 | 120 | |
0756eb3c PH |
121 | if( rc != SASL_OK ) |
122 | log_write(0, LOG_PANIC_DIE|LOG_CONFIG_FOR, "%s authenticator: " | |
123 | "couldn't initialise Cyrus SASL library.", ablock->name); | |
124 | ||
125 | rc=sasl_server_new(CS ob->server_service, CS primary_hostname, | |
126 | CS ob->server_realm, NULL, NULL, NULL, 0, &conn); | |
127 | if( rc != SASL_OK ) | |
128 | log_write(0, LOG_PANIC_DIE|LOG_CONFIG_FOR, "%s authenticator: " | |
129 | "couldn't initialise Cyrus SASL server connection.", ablock->name); | |
130 | ||
131 | rc=sasl_listmech(conn, NULL, "", ":", "", (const char **)(&list), &len, &i); | |
132 | if( rc != SASL_OK ) | |
133 | log_write(0, LOG_PANIC_DIE|LOG_CONFIG_FOR, "%s authenticator: " | |
134 | "couldn't get Cyrus SASL mechanism list.", ablock->name); | |
135 | ||
136 | i=':'; | |
137 | listptr=list; | |
138 | ||
139 | HDEBUG(D_auth) debug_printf("Cyrus SASL knows about: %s\n", list); | |
140 | ||
141 | /* the store_get / store_reset mechanism is hierarchical | |
142 | * the hierarchy is stored for us behind our back. This point | |
143 | * creates a hierarchy point for this function. | |
144 | */ | |
145 | rs_point=store_get(0); | |
146 | ||
147 | /* loop until either we get to the end of the list, or we match the | |
148 | * public name of this authenticator | |
149 | */ | |
150 | while( ( buffer = string_nextinlist(&listptr, &i, NULL, 0) ) && | |
151 | strcmpic(buffer,ob->server_mech) ); | |
152 | ||
153 | if(!buffer) | |
154 | log_write(0, LOG_PANIC_DIE|LOG_CONFIG_FOR, "%s authenticator: " | |
155 | "Cyrus SASL doesn't know about mechanism %s.", ablock->name, ob->server_mech); | |
156 | ||
157 | store_reset(rs_point); | |
158 | ||
159 | HDEBUG(D_auth) debug_printf("Cyrus SASL driver %s: %s initialised\n", ablock->name, ablock->public_name); | |
160 | ||
161 | /* make sure that if we get here then we're allowed to advertise. */ | |
162 | ablock->server = TRUE; | |
163 | ||
164 | sasl_dispose(&conn); | |
165 | sasl_done(); | |
166 | } | |
167 | ||
168 | /************************************************* | |
169 | * Server entry point * | |
170 | *************************************************/ | |
171 | ||
172 | /* For interface, see auths/README */ | |
173 | ||
174 | /* note, we don't care too much about memory allocation in this, because this is entirely | |
175 | * within a shortlived child | |
176 | */ | |
177 | ||
178 | int | |
179 | auth_cyrus_sasl_server(auth_instance *ablock, uschar *data) | |
180 | { | |
181 | auth_cyrus_sasl_options_block *ob = | |
182 | (auth_cyrus_sasl_options_block *)(ablock->options_block); | |
183 | uschar *output, *out2, *input, *clear, *hname; | |
184 | uschar *debug = NULL; /* Stops compiler complaining */ | |
185 | sasl_callback_t cbs[]={{SASL_CB_LIST_END, NULL, NULL}}; | |
186 | sasl_conn_t *conn; | |
187 | int rc, firsttime=1, clen; | |
188 | unsigned int inlen, outlen; | |
189 | ||
190 | input=data; | |
191 | inlen=Ustrlen(data); | |
192 | ||
193 | HDEBUG(D_auth) debug=string_copy(data); | |
194 | ||
195 | hname=expand_string(ob->server_hostname); | |
196 | if(hname == NULL) | |
197 | { | |
198 | auth_defer_msg = expand_string_message; | |
199 | return DEFER; | |
200 | } | |
201 | ||
202 | if(inlen) | |
203 | { | |
204 | clen=auth_b64decode(input, &clear); | |
205 | if(clen < 0) | |
206 | { | |
207 | return BAD64; | |
208 | } | |
209 | input=clear; | |
210 | inlen=clen; | |
211 | } | |
212 | ||
213 | rc=sasl_server_init(cbs, "exim"); | |
214 | if (rc != SASL_OK) | |
215 | { | |
216 | auth_defer_msg = US"couldn't initialise Cyrus SASL library"; | |
217 | return DEFER; | |
218 | } | |
219 | ||
acb1b346 PH |
220 | rc=sasl_server_new(CS ob->server_service, CS hname, CS ob->server_realm, NULL, |
221 | NULL, NULL, 0, &conn); | |
222 | ||
0756eb3c PH |
223 | if( rc != SASL_OK ) |
224 | { | |
225 | auth_defer_msg = US"couldn't initialise Cyrus SASL connection"; | |
226 | sasl_done(); | |
227 | return DEFER; | |
228 | } | |
229 | ||
230 | rc=SASL_CONTINUE; | |
231 | ||
232 | while(rc==SASL_CONTINUE) | |
233 | { | |
234 | if(firsttime) | |
235 | { | |
236 | firsttime=0; | |
237 | HDEBUG(D_auth) debug_printf("Calling sasl_server_start(%s,\"%s\")\n", ob->server_mech, debug); | |
238 | rc=sasl_server_start(conn, CS ob->server_mech, inlen?CS input:NULL, inlen, | |
239 | (const char **)(&output), &outlen); | |
240 | } | |
241 | else | |
242 | { | |
243 | /* make sure that we have a null-terminated string */ | |
244 | out2=store_get(outlen+1); | |
245 | memcpy(out2,output,outlen); | |
246 | out2[outlen]='\0'; | |
247 | if((rc=auth_get_data(&input, out2, outlen))!=OK) | |
248 | { | |
249 | /* we couldn't get the data, so free up the library before | |
250 | * returning whatever error we get */ | |
251 | sasl_dispose(&conn); | |
252 | sasl_done(); | |
253 | return rc; | |
254 | } | |
255 | inlen=Ustrlen(input); | |
256 | ||
257 | HDEBUG(D_auth) debug=string_copy(input); | |
258 | if(inlen) | |
259 | { | |
260 | clen=auth_b64decode(input, &clear); | |
261 | if(clen < 0) | |
262 | { | |
263 | sasl_dispose(&conn); | |
264 | sasl_done(); | |
265 | return BAD64; | |
266 | } | |
267 | input=clear; | |
268 | inlen=clen; | |
269 | } | |
270 | ||
271 | HDEBUG(D_auth) debug_printf("Calling sasl_server_step(\"%s\")\n", debug); | |
272 | rc=sasl_server_step(conn, CS input, inlen, (const char **)(&output), &outlen); | |
273 | } | |
274 | if(rc==SASL_BADPROT) | |
275 | { | |
276 | sasl_dispose(&conn); | |
277 | sasl_done(); | |
278 | return UNEXPECTED; | |
279 | } | |
280 | else if( rc==SASL_FAIL || rc==SASL_BUFOVER | |
281 | || rc==SASL_BADMAC || rc==SASL_BADAUTH | |
282 | || rc==SASL_NOAUTHZ || rc==SASL_ENCRYPT | |
283 | || rc==SASL_EXPIRED || rc==SASL_DISABLED | |
284 | || rc==SASL_NOUSER ) | |
285 | { | |
286 | /* these are considered permanent failure codes */ | |
287 | HDEBUG(D_auth) | |
288 | debug_printf("Cyrus SASL permanent failure %d (%s)\n", rc, sasl_errstring(rc, NULL, NULL)); | |
289 | log_write(0, LOG_REJECT, "%s authenticator (%s):\n " | |
290 | "Cyrus SASL permanent failure: %s", ablock->name, ob->server_mech, | |
291 | sasl_errstring(rc, NULL, NULL)); | |
292 | sasl_dispose(&conn); | |
293 | sasl_done(); | |
294 | return FAIL; | |
295 | } | |
296 | else if(rc==SASL_NOMECH) | |
297 | { | |
298 | /* this is a temporary failure, because the mechanism is not | |
299 | * available for this user. If it wasn't available at all, we | |
300 | * shouldn't have got here in the first place... | |
301 | */ | |
302 | HDEBUG(D_auth) | |
303 | debug_printf("Cyrus SASL temporary failure %d (%s)\n", rc, sasl_errstring(rc, NULL, NULL)); | |
304 | auth_defer_msg = | |
305 | string_sprintf("Cyrus SASL: mechanism %s not available", ob->server_mech); | |
306 | sasl_dispose(&conn); | |
307 | sasl_done(); | |
308 | return DEFER; | |
309 | } | |
310 | else if(!(rc==SASL_OK || rc==SASL_CONTINUE)) | |
311 | { | |
312 | /* Anything else is a temporary failure, and we'll let SASL print out | |
313 | * the error string for us | |
314 | */ | |
315 | HDEBUG(D_auth) | |
316 | debug_printf("Cyrus SASL temporary failure %d (%s)\n", rc, sasl_errstring(rc, NULL, NULL)); | |
317 | auth_defer_msg = | |
318 | string_sprintf("Cyrus SASL: %s", sasl_errstring(rc, NULL, NULL)); | |
319 | sasl_dispose(&conn); | |
320 | sasl_done(); | |
321 | return DEFER; | |
322 | } | |
323 | else if(rc==SASL_OK) | |
324 | { | |
f78eb7c6 PH |
325 | /* Get the username and copy it into $auth1 and $1. The former is now the |
326 | preferred variable; the latter is the original variable. */ | |
327 | rc = sasl_getprop(conn, SASL_USERNAME, (const void **)(&out2)); | |
328 | auth_vars[0] = expand_nstring[1] = string_copy(out2); | |
329 | expand_nlength[1] = Ustrlen(expand_nstring[1]); | |
330 | expand_nmax = 1; | |
0756eb3c PH |
331 | |
332 | HDEBUG(D_auth) | |
16ff981e | 333 | debug_printf("Cyrus SASL %s authentication succeeded for %s\n", ob->server_mech, out2); |
0756eb3c PH |
334 | /* close down the connection, freeing up library's memory */ |
335 | sasl_dispose(&conn); | |
336 | sasl_done(); | |
16ff981e PH |
337 | |
338 | /* Expand server_condition as an authorization check */ | |
339 | return auth_check_serv_cond(ablock); | |
0756eb3c PH |
340 | } |
341 | } | |
342 | /* NOTREACHED */ | |
343 | return 0; /* Stop compiler complaints */ | |
344 | } | |
345 | ||
6545de78 PP |
346 | /************************************************* |
347 | * Diagnostic API * | |
348 | *************************************************/ | |
349 | ||
350 | void | |
351 | auth_cyrus_sasl_version_report(FILE *f) | |
352 | { | |
353 | const char *implementation, *version; | |
354 | sasl_version_info(&implementation, &version, NULL, NULL, NULL, NULL); | |
355 | fprintf(f, "Library version: Cyrus SASL: Compile: %d.%d.%d\n" | |
356 | " Runtime: %s [%s]\n", | |
357 | SASL_VERSION_MAJOR, SASL_VERSION_MINOR, SASL_VERSION_STEP, | |
358 | version, implementation); | |
359 | } | |
360 | ||
0756eb3c PH |
361 | /************************************************* |
362 | * Client entry point * | |
363 | *************************************************/ | |
364 | ||
365 | /* For interface, see auths/README */ | |
366 | ||
367 | int | |
368 | auth_cyrus_sasl_client( | |
369 | auth_instance *ablock, /* authenticator block */ | |
370 | smtp_inblock *inblock, /* input connection */ | |
371 | smtp_outblock *outblock, /* output connection */ | |
372 | int timeout, /* command timeout */ | |
373 | uschar *buffer, /* for reading response */ | |
374 | int buffsize) /* size of buffer */ | |
375 | { | |
376 | /* We don't support clients (yet) in this implementation of cyrus_sasl */ | |
377 | return FAIL; | |
378 | } | |
379 | ||
380 | #endif /* AUTH_CYRUS_SASL */ | |
381 | ||
382 | /* End of cyrus_sasl.c */ |