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1 | /* $Cambridge: exim/src/src/auths/cyrus_sasl.c,v 1.1 2004/10/07 13:10:01 ph10 Exp $ */ |
2 | ||
3 | /************************************************* | |
4 | * Exim - an Internet mail transport agent * | |
5 | *************************************************/ | |
6 | ||
7 | /* Copyright (c) University of Cambridge 1995 - 2003 */ | |
8 | /* See the file NOTICE for conditions of use and distribution. */ | |
9 | ||
10 | /* This code was contributed by Matthew Byng-Maddick */ | |
11 | ||
12 | /* Copyright (c) A L Digital 2004 */ | |
13 | ||
14 | /* A generic (mechanism independent) Cyrus SASL authenticator. */ | |
15 | ||
16 | ||
17 | #include "../exim.h" | |
18 | ||
19 | ||
20 | /* We can't just compile this code and allow the library mechanism to omit the | |
21 | functions if they are not wanted, because we need to have the Cyrus SASL header | |
22 | available for compiling. Therefore, compile these functions only if | |
23 | AUTH_CYRUS_SASL is defined. However, some compilers don't like compiling empty | |
24 | modules, so keep them happy with a dummy when skipping the rest. Make it | |
25 | reference itself to stop picky compilers complaining that it is unused, and put | |
26 | in a dummy argument to stop even pickier compilers complaining about infinite | |
27 | loops. */ | |
28 | ||
29 | #ifndef AUTH_CYRUS_SASL | |
30 | static void dummy(int x) { dummy(x-1); } | |
31 | #else | |
32 | ||
33 | ||
34 | #include <sasl/sasl.h> | |
35 | #include "cyrus_sasl.h" | |
36 | ||
37 | /* Options specific to the cyrus_sasl authentication mechanism. */ | |
38 | ||
39 | optionlist auth_cyrus_sasl_options[] = { | |
40 | { "server_hostname", opt_stringptr, | |
41 | (void *)(offsetof(auth_cyrus_sasl_options_block, server_hostname)) }, | |
42 | { "server_mech", opt_stringptr, | |
43 | (void *)(offsetof(auth_cyrus_sasl_options_block, server_mech)) }, | |
44 | { "server_realm", opt_stringptr, | |
45 | (void *)(offsetof(auth_cyrus_sasl_options_block, server_realm)) }, | |
46 | { "server_service", opt_stringptr, | |
47 | (void *)(offsetof(auth_cyrus_sasl_options_block, server_service)) } | |
48 | }; | |
49 | ||
50 | /* Size of the options list. An extern variable has to be used so that its | |
51 | address can appear in the tables drtables.c. */ | |
52 | ||
53 | int auth_cyrus_sasl_options_count = | |
54 | sizeof(auth_cyrus_sasl_options)/sizeof(optionlist); | |
55 | ||
56 | /* Default private options block for the contidion authentication method. */ | |
57 | ||
58 | auth_cyrus_sasl_options_block auth_cyrus_sasl_option_defaults = { | |
59 | US"smtp", /* server_service */ | |
60 | US"$primary_hostname", /* server_hostname */ | |
61 | NULL, /* server_realm */ | |
62 | NULL /* server_mech */ | |
63 | }; | |
64 | ||
65 | ||
66 | /************************************************* | |
67 | * Initialization entry point * | |
68 | *************************************************/ | |
69 | ||
70 | /* Called for each instance, after its options have been read, to | |
71 | enable consistency checks to be done, or anything else that needs | |
72 | to be set up. */ | |
73 | ||
74 | void | |
75 | auth_cyrus_sasl_init(auth_instance *ablock) | |
76 | { | |
77 | auth_cyrus_sasl_options_block *ob = | |
78 | (auth_cyrus_sasl_options_block *)(ablock->options_block); | |
79 | sasl_callback_t cbs[]={{SASL_CB_LIST_END, NULL, NULL}}; | |
80 | sasl_conn_t *conn; | |
81 | uschar *list, *listptr, *buffer; | |
82 | int rc, i; | |
83 | unsigned int len; | |
84 | uschar *rs_point; | |
85 | ||
86 | /* default the mechanism to our "public name" */ | |
87 | if(ob->server_mech == NULL) | |
88 | ob->server_mech=string_copy(ablock->public_name); | |
89 | ||
90 | /* we're going to initialise the library to check that there is an | |
91 | * authenticator of type whatever mechanism we're using | |
92 | */ | |
93 | rc=sasl_server_init(cbs, "exim"); | |
94 | if( rc != SASL_OK ) | |
95 | log_write(0, LOG_PANIC_DIE|LOG_CONFIG_FOR, "%s authenticator: " | |
96 | "couldn't initialise Cyrus SASL library.", ablock->name); | |
97 | ||
98 | rc=sasl_server_new(CS ob->server_service, CS primary_hostname, | |
99 | CS ob->server_realm, NULL, NULL, NULL, 0, &conn); | |
100 | if( rc != SASL_OK ) | |
101 | log_write(0, LOG_PANIC_DIE|LOG_CONFIG_FOR, "%s authenticator: " | |
102 | "couldn't initialise Cyrus SASL server connection.", ablock->name); | |
103 | ||
104 | rc=sasl_listmech(conn, NULL, "", ":", "", (const char **)(&list), &len, &i); | |
105 | if( rc != SASL_OK ) | |
106 | log_write(0, LOG_PANIC_DIE|LOG_CONFIG_FOR, "%s authenticator: " | |
107 | "couldn't get Cyrus SASL mechanism list.", ablock->name); | |
108 | ||
109 | i=':'; | |
110 | listptr=list; | |
111 | ||
112 | HDEBUG(D_auth) debug_printf("Cyrus SASL knows about: %s\n", list); | |
113 | ||
114 | /* the store_get / store_reset mechanism is hierarchical | |
115 | * the hierarchy is stored for us behind our back. This point | |
116 | * creates a hierarchy point for this function. | |
117 | */ | |
118 | rs_point=store_get(0); | |
119 | ||
120 | /* loop until either we get to the end of the list, or we match the | |
121 | * public name of this authenticator | |
122 | */ | |
123 | while( ( buffer = string_nextinlist(&listptr, &i, NULL, 0) ) && | |
124 | strcmpic(buffer,ob->server_mech) ); | |
125 | ||
126 | if(!buffer) | |
127 | log_write(0, LOG_PANIC_DIE|LOG_CONFIG_FOR, "%s authenticator: " | |
128 | "Cyrus SASL doesn't know about mechanism %s.", ablock->name, ob->server_mech); | |
129 | ||
130 | store_reset(rs_point); | |
131 | ||
132 | HDEBUG(D_auth) debug_printf("Cyrus SASL driver %s: %s initialised\n", ablock->name, ablock->public_name); | |
133 | ||
134 | /* make sure that if we get here then we're allowed to advertise. */ | |
135 | ablock->server = TRUE; | |
136 | ||
137 | sasl_dispose(&conn); | |
138 | sasl_done(); | |
139 | } | |
140 | ||
141 | /************************************************* | |
142 | * Server entry point * | |
143 | *************************************************/ | |
144 | ||
145 | /* For interface, see auths/README */ | |
146 | ||
147 | /* note, we don't care too much about memory allocation in this, because this is entirely | |
148 | * within a shortlived child | |
149 | */ | |
150 | ||
151 | int | |
152 | auth_cyrus_sasl_server(auth_instance *ablock, uschar *data) | |
153 | { | |
154 | auth_cyrus_sasl_options_block *ob = | |
155 | (auth_cyrus_sasl_options_block *)(ablock->options_block); | |
156 | uschar *output, *out2, *input, *clear, *hname; | |
157 | uschar *debug = NULL; /* Stops compiler complaining */ | |
158 | sasl_callback_t cbs[]={{SASL_CB_LIST_END, NULL, NULL}}; | |
159 | sasl_conn_t *conn; | |
160 | int rc, firsttime=1, clen; | |
161 | unsigned int inlen, outlen; | |
162 | ||
163 | input=data; | |
164 | inlen=Ustrlen(data); | |
165 | ||
166 | HDEBUG(D_auth) debug=string_copy(data); | |
167 | ||
168 | hname=expand_string(ob->server_hostname); | |
169 | if(hname == NULL) | |
170 | { | |
171 | auth_defer_msg = expand_string_message; | |
172 | return DEFER; | |
173 | } | |
174 | ||
175 | if(inlen) | |
176 | { | |
177 | clen=auth_b64decode(input, &clear); | |
178 | if(clen < 0) | |
179 | { | |
180 | return BAD64; | |
181 | } | |
182 | input=clear; | |
183 | inlen=clen; | |
184 | } | |
185 | ||
186 | rc=sasl_server_init(cbs, "exim"); | |
187 | if (rc != SASL_OK) | |
188 | { | |
189 | auth_defer_msg = US"couldn't initialise Cyrus SASL library"; | |
190 | return DEFER; | |
191 | } | |
192 | ||
193 | rc=sasl_server_new(CS ob->server_service, CS ob->server_hostname, | |
194 | CS ob->server_realm, NULL, NULL, NULL, 0, &conn); | |
195 | if( rc != SASL_OK ) | |
196 | { | |
197 | auth_defer_msg = US"couldn't initialise Cyrus SASL connection"; | |
198 | sasl_done(); | |
199 | return DEFER; | |
200 | } | |
201 | ||
202 | rc=SASL_CONTINUE; | |
203 | ||
204 | while(rc==SASL_CONTINUE) | |
205 | { | |
206 | if(firsttime) | |
207 | { | |
208 | firsttime=0; | |
209 | HDEBUG(D_auth) debug_printf("Calling sasl_server_start(%s,\"%s\")\n", ob->server_mech, debug); | |
210 | rc=sasl_server_start(conn, CS ob->server_mech, inlen?CS input:NULL, inlen, | |
211 | (const char **)(&output), &outlen); | |
212 | } | |
213 | else | |
214 | { | |
215 | /* make sure that we have a null-terminated string */ | |
216 | out2=store_get(outlen+1); | |
217 | memcpy(out2,output,outlen); | |
218 | out2[outlen]='\0'; | |
219 | if((rc=auth_get_data(&input, out2, outlen))!=OK) | |
220 | { | |
221 | /* we couldn't get the data, so free up the library before | |
222 | * returning whatever error we get */ | |
223 | sasl_dispose(&conn); | |
224 | sasl_done(); | |
225 | return rc; | |
226 | } | |
227 | inlen=Ustrlen(input); | |
228 | ||
229 | HDEBUG(D_auth) debug=string_copy(input); | |
230 | if(inlen) | |
231 | { | |
232 | clen=auth_b64decode(input, &clear); | |
233 | if(clen < 0) | |
234 | { | |
235 | sasl_dispose(&conn); | |
236 | sasl_done(); | |
237 | return BAD64; | |
238 | } | |
239 | input=clear; | |
240 | inlen=clen; | |
241 | } | |
242 | ||
243 | HDEBUG(D_auth) debug_printf("Calling sasl_server_step(\"%s\")\n", debug); | |
244 | rc=sasl_server_step(conn, CS input, inlen, (const char **)(&output), &outlen); | |
245 | } | |
246 | if(rc==SASL_BADPROT) | |
247 | { | |
248 | sasl_dispose(&conn); | |
249 | sasl_done(); | |
250 | return UNEXPECTED; | |
251 | } | |
252 | else if( rc==SASL_FAIL || rc==SASL_BUFOVER | |
253 | || rc==SASL_BADMAC || rc==SASL_BADAUTH | |
254 | || rc==SASL_NOAUTHZ || rc==SASL_ENCRYPT | |
255 | || rc==SASL_EXPIRED || rc==SASL_DISABLED | |
256 | || rc==SASL_NOUSER ) | |
257 | { | |
258 | /* these are considered permanent failure codes */ | |
259 | HDEBUG(D_auth) | |
260 | debug_printf("Cyrus SASL permanent failure %d (%s)\n", rc, sasl_errstring(rc, NULL, NULL)); | |
261 | log_write(0, LOG_REJECT, "%s authenticator (%s):\n " | |
262 | "Cyrus SASL permanent failure: %s", ablock->name, ob->server_mech, | |
263 | sasl_errstring(rc, NULL, NULL)); | |
264 | sasl_dispose(&conn); | |
265 | sasl_done(); | |
266 | return FAIL; | |
267 | } | |
268 | else if(rc==SASL_NOMECH) | |
269 | { | |
270 | /* this is a temporary failure, because the mechanism is not | |
271 | * available for this user. If it wasn't available at all, we | |
272 | * shouldn't have got here in the first place... | |
273 | */ | |
274 | HDEBUG(D_auth) | |
275 | debug_printf("Cyrus SASL temporary failure %d (%s)\n", rc, sasl_errstring(rc, NULL, NULL)); | |
276 | auth_defer_msg = | |
277 | string_sprintf("Cyrus SASL: mechanism %s not available", ob->server_mech); | |
278 | sasl_dispose(&conn); | |
279 | sasl_done(); | |
280 | return DEFER; | |
281 | } | |
282 | else if(!(rc==SASL_OK || rc==SASL_CONTINUE)) | |
283 | { | |
284 | /* Anything else is a temporary failure, and we'll let SASL print out | |
285 | * the error string for us | |
286 | */ | |
287 | HDEBUG(D_auth) | |
288 | debug_printf("Cyrus SASL temporary failure %d (%s)\n", rc, sasl_errstring(rc, NULL, NULL)); | |
289 | auth_defer_msg = | |
290 | string_sprintf("Cyrus SASL: %s", sasl_errstring(rc, NULL, NULL)); | |
291 | sasl_dispose(&conn); | |
292 | sasl_done(); | |
293 | return DEFER; | |
294 | } | |
295 | else if(rc==SASL_OK) | |
296 | { | |
297 | /* get the username and copy it into $1 */ | |
298 | rc=sasl_getprop(conn, SASL_USERNAME, (const void **)(&out2)); | |
299 | expand_nstring[1]=string_copy(out2); | |
300 | expand_nlength[1]=Ustrlen(expand_nstring[1]); | |
301 | expand_nmax=1; | |
302 | ||
303 | HDEBUG(D_auth) | |
304 | debug_printf("Cyrus SASL %s authentiction succeeded for %s\n", ob->server_mech, out2); | |
305 | /* close down the connection, freeing up library's memory */ | |
306 | sasl_dispose(&conn); | |
307 | sasl_done(); | |
308 | return OK; | |
309 | } | |
310 | } | |
311 | /* NOTREACHED */ | |
312 | return 0; /* Stop compiler complaints */ | |
313 | } | |
314 | ||
315 | /************************************************* | |
316 | * Client entry point * | |
317 | *************************************************/ | |
318 | ||
319 | /* For interface, see auths/README */ | |
320 | ||
321 | int | |
322 | auth_cyrus_sasl_client( | |
323 | auth_instance *ablock, /* authenticator block */ | |
324 | smtp_inblock *inblock, /* input connection */ | |
325 | smtp_outblock *outblock, /* output connection */ | |
326 | int timeout, /* command timeout */ | |
327 | uschar *buffer, /* for reading response */ | |
328 | int buffsize) /* size of buffer */ | |
329 | { | |
330 | /* We don't support clients (yet) in this implementation of cyrus_sasl */ | |
331 | return FAIL; | |
332 | } | |
333 | ||
334 | #endif /* AUTH_CYRUS_SASL */ | |
335 | ||
336 | /* End of cyrus_sasl.c */ |