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0756eb3c PH |
1 | /************************************************* |
2 | * Exim - an Internet mail transport agent * | |
3 | *************************************************/ | |
4 | ||
f9ba5e22 | 5 | /* Copyright (c) University of Cambridge 1995 - 2018 */ |
0756eb3c PH |
6 | /* See the file NOTICE for conditions of use and distribution. */ |
7 | ||
8 | /* This file, which provides support for Microsoft's Secure Password | |
9 | Authentication, was contributed by Marc Prud'hommeaux. Tom Kistner added SPA | |
10 | server support. I (PH) have only modified it in very trivial ways. | |
11 | ||
12 | References: | |
13 | http://www.innovation.ch/java/ntlm.html | |
14 | http://www.kuro5hin.org/story/2002/4/28/1436/66154 | |
55c75993 | 15 | http://download.microsoft.com/download/9/5/e/95ef66af-9026-4bb0-a41d-a4f81802d92c/%5bMS-SMTP%5d.pdf |
0756eb3c PH |
16 | |
17 | * It seems that some systems have existing but different definitions of some | |
18 | * of the following types. I received a complaint about "int16" causing | |
19 | * compilation problems. So I (PH) have renamed them all, to be on the safe | |
20 | * side, by adding 'x' on the end. See auths/auth-spa.h. | |
21 | ||
22 | * typedef signed short int16; | |
23 | * typedef unsigned short uint16; | |
24 | * typedef unsigned uint32; | |
25 | * typedef unsigned char uint8; | |
26 | ||
16ff981e PH |
27 | 07-August-2003: PH: Patched up the code to avoid assert bombouts for stupid |
28 | input data. Find appropriate comment by grepping for "PH". | |
29 | 16-October-2006: PH: Added a call to auth_check_serv_cond() at the end | |
55c75993 | 30 | 05-June-2010: PP: handle SASL initial response |
0756eb3c PH |
31 | */ |
32 | ||
33 | ||
34 | #include "../exim.h" | |
35 | #include "spa.h" | |
36 | ||
37 | /* #define DEBUG_SPA */ | |
38 | ||
39 | #ifdef DEBUG_SPA | |
40 | #define DSPA(x,y,z) debug_printf(x,y,z) | |
41 | #else | |
42 | #define DSPA(x,y,z) | |
43 | #endif | |
44 | ||
45 | /* Options specific to the spa authentication mechanism. */ | |
46 | ||
47 | optionlist auth_spa_options[] = { | |
48 | { "client_domain", opt_stringptr, | |
13a4b4c1 | 49 | OPT_OFF(auth_spa_options_block, spa_domain) }, |
0756eb3c | 50 | { "client_password", opt_stringptr, |
13a4b4c1 | 51 | OPT_OFF(auth_spa_options_block, spa_password) }, |
0756eb3c | 52 | { "client_username", opt_stringptr, |
13a4b4c1 | 53 | OPT_OFF(auth_spa_options_block, spa_username) }, |
0756eb3c | 54 | { "server_password", opt_stringptr, |
13a4b4c1 | 55 | OPT_OFF(auth_spa_options_block, spa_serverpassword) } |
0756eb3c PH |
56 | }; |
57 | ||
58 | /* Size of the options list. An extern variable has to be used so that its | |
59 | address can appear in the tables drtables.c. */ | |
60 | ||
61 | int auth_spa_options_count = | |
62 | sizeof(auth_spa_options)/sizeof(optionlist); | |
63 | ||
4c04137d | 64 | /* Default private options block for the condition authentication method. */ |
0756eb3c PH |
65 | |
66 | auth_spa_options_block auth_spa_option_defaults = { | |
67 | NULL, /* spa_password */ | |
68 | NULL, /* spa_username */ | |
69 | NULL, /* spa_domain */ | |
70 | NULL /* spa_serverpassword (for server side use) */ | |
71 | }; | |
72 | ||
73 | ||
d185889f JH |
74 | #ifdef MACRO_PREDEF |
75 | ||
76 | /* Dummy values */ | |
77 | void auth_spa_init(auth_instance *ablock) {} | |
78 | int auth_spa_server(auth_instance *ablock, uschar *data) {return 0;} | |
251b9eb4 JH |
79 | int auth_spa_client(auth_instance *ablock, void * sx, int timeout, |
80 | uschar *buffer, int buffsize) {return 0;} | |
d185889f JH |
81 | |
82 | #else /*!MACRO_PREDEF*/ | |
83 | ||
84 | ||
85 | ||
86 | ||
0756eb3c PH |
87 | /************************************************* |
88 | * Initialization entry point * | |
89 | *************************************************/ | |
90 | ||
91 | /* Called for each instance, after its options have been read, to | |
92 | enable consistency checks to be done, or anything else that needs | |
93 | to be set up. */ | |
94 | ||
95 | void | |
96 | auth_spa_init(auth_instance *ablock) | |
97 | { | |
98 | auth_spa_options_block *ob = | |
99 | (auth_spa_options_block *)(ablock->options_block); | |
100 | ||
101 | /* The public name defaults to the authenticator name */ | |
102 | ||
103 | if (ablock->public_name == NULL) ablock->public_name = ablock->name; | |
104 | ||
105 | /* Both username and password must be set for a client */ | |
106 | ||
107 | if ((ob->spa_username == NULL) != (ob->spa_password == NULL)) | |
108 | log_write(0, LOG_PANIC_DIE|LOG_CONFIG_FOR, "%s authenticator:\n " | |
109 | "one of client_username and client_password cannot be set without " | |
110 | "the other", ablock->name); | |
111 | ablock->client = ob->spa_username != NULL; | |
112 | ||
113 | /* For a server we have just one option */ | |
114 | ||
115 | ablock->server = ob->spa_serverpassword != NULL; | |
116 | } | |
117 | ||
118 | ||
119 | ||
120 | /************************************************* | |
121 | * Server entry point * | |
122 | *************************************************/ | |
123 | ||
124 | /* For interface, see auths/README */ | |
125 | ||
5903c6ff | 126 | #define CVAL(buf,pos) ((US (buf))[pos]) |
0756eb3c PH |
127 | #define PVAL(buf,pos) ((unsigned)CVAL(buf,pos)) |
128 | #define SVAL(buf,pos) (PVAL(buf,pos)|PVAL(buf,(pos)+1)<<8) | |
129 | #define IVAL(buf,pos) (SVAL(buf,pos)|SVAL(buf,(pos)+2)<<16) | |
130 | ||
131 | int | |
132 | auth_spa_server(auth_instance *ablock, uschar *data) | |
133 | { | |
134 | auth_spa_options_block *ob = (auth_spa_options_block *)(ablock->options_block); | |
135 | uint8x lmRespData[24]; | |
136 | uint8x ntRespData[24]; | |
137 | SPAAuthRequest request; | |
138 | SPAAuthChallenge challenge; | |
139 | SPAAuthResponse response; | |
140 | SPAAuthResponse *responseptr = &response; | |
141 | uschar msgbuf[2048]; | |
142 | uschar *clearpass; | |
143 | ||
55c75993 PP |
144 | /* send a 334, MS Exchange style, and grab the client's request, |
145 | unless we already have it via an initial response. */ | |
0756eb3c | 146 | |
55c75993 PP |
147 | if ((*data == '\0') && |
148 | (auth_get_no64_data(&data, US"NTLM supported") != OK)) | |
0756eb3c PH |
149 | { |
150 | /* something borked */ | |
151 | return FAIL; | |
152 | } | |
153 | ||
5903c6ff | 154 | if (spa_base64_to_bits(CS (&request), sizeof(request), CCS (data)) < 0) |
0756eb3c PH |
155 | { |
156 | DEBUG(D_auth) debug_printf("auth_spa_server(): bad base64 data in " | |
157 | "request: %s\n", data); | |
158 | return FAIL; | |
159 | } | |
160 | ||
161 | /* create a challenge and send it back */ | |
162 | ||
163 | spa_build_auth_challenge(&request,&challenge); | |
164 | spa_bits_to_base64 (msgbuf, (unsigned char*)&challenge, | |
165 | spa_request_length(&challenge)); | |
166 | ||
167 | if (auth_get_no64_data(&data, msgbuf) != OK) | |
168 | { | |
169 | /* something borked */ | |
170 | return FAIL; | |
171 | } | |
172 | ||
173 | /* dump client response */ | |
5903c6ff | 174 | if (spa_base64_to_bits(CS (&response), sizeof(response), CCS (data)) < 0) |
0756eb3c PH |
175 | { |
176 | DEBUG(D_auth) debug_printf("auth_spa_server(): bad base64 data in " | |
177 | "response: %s\n", data); | |
178 | return FAIL; | |
179 | } | |
180 | ||
0756eb3c PH |
181 | /*************************************************************** |
182 | PH 07-Aug-2003: The original code here was this: | |
183 | ||
184 | Ustrcpy(msgbuf, unicodeToString(((char*)responseptr) + | |
185 | IVAL(&responseptr->uUser.offset,0), | |
186 | SVAL(&responseptr->uUser.len,0)/2) ); | |
187 | ||
188 | However, if the response data is too long, unicodeToString bombs out on | |
189 | an assertion failure. It uses a 1024 fixed buffer. Bombing out is not a good | |
190 | idea. It's too messy to try to rework that function to return an error because | |
191 | it is called from a number of other places in the auth-spa.c module. Instead, | |
192 | since it is a very small function, I reproduce its code here, with a size check | |
193 | that causes failure if the size of msgbuf is exceeded. ****/ | |
194 | ||
195 | { | |
196 | int i; | |
197 | char *p = ((char*)responseptr) + IVAL(&responseptr->uUser.offset,0); | |
198 | int len = SVAL(&responseptr->uUser.len,0)/2; | |
199 | ||
200 | if (len + 1 >= sizeof(msgbuf)) return FAIL; | |
201 | for (i = 0; i < len; ++i) | |
202 | { | |
203 | msgbuf[i] = *p & 0x7f; | |
204 | p += 2; | |
205 | } | |
206 | msgbuf[i] = 0; | |
207 | } | |
208 | ||
209 | /***************************************************************/ | |
210 | ||
f78eb7c6 | 211 | /* Put the username in $auth1 and $1. The former is now the preferred variable; |
f68fe5f6 PP |
212 | the latter is the original variable. These have to be out of stack memory, and |
213 | need to be available once known even if not authenticated, for error messages | |
214 | (server_set_id, which only makes it to authenticated_id if we return OK) */ | |
f78eb7c6 | 215 | |
f68fe5f6 | 216 | auth_vars[0] = expand_nstring[1] = string_copy(msgbuf); |
0756eb3c PH |
217 | expand_nlength[1] = Ustrlen(msgbuf); |
218 | expand_nmax = 1; | |
219 | ||
f78eb7c6 PH |
220 | debug_print_string(ablock->server_debug_string); /* customized debug */ |
221 | ||
0756eb3c PH |
222 | /* look up password */ |
223 | ||
224 | clearpass = expand_string(ob->spa_serverpassword); | |
225 | if (clearpass == NULL) | |
226 | { | |
8768d548 | 227 | if (f.expand_string_forcedfail) |
0756eb3c PH |
228 | { |
229 | DEBUG(D_auth) debug_printf("auth_spa_server(): forced failure while " | |
230 | "expanding spa_serverpassword\n"); | |
f68fe5f6 | 231 | return FAIL; |
0756eb3c PH |
232 | } |
233 | else | |
234 | { | |
235 | DEBUG(D_auth) debug_printf("auth_spa_server(): error while expanding " | |
236 | "spa_serverpassword: %s\n", expand_string_message); | |
f68fe5f6 | 237 | return DEFER; |
0756eb3c PH |
238 | } |
239 | } | |
240 | ||
241 | /* create local hash copy */ | |
242 | ||
243 | spa_smb_encrypt (clearpass, challenge.challengeData, lmRespData); | |
244 | spa_smb_nt_encrypt (clearpass, challenge.challengeData, ntRespData); | |
245 | ||
246 | /* compare NT hash (LM may not be available) */ | |
247 | ||
248 | if (memcmp(ntRespData, | |
249 | ((unsigned char*)responseptr)+IVAL(&responseptr->ntResponse.offset,0), | |
250 | 24) == 0) | |
251 | /* success. we have a winner. */ | |
08488c86 | 252 | { |
f68fe5f6 | 253 | return auth_check_serv_cond(ablock); |
08488c86 | 254 | } |
16ff981e PH |
255 | |
256 | /* Expand server_condition as an authorization check (PH) */ | |
0756eb3c | 257 | |
f68fe5f6 | 258 | return FAIL; |
0756eb3c PH |
259 | } |
260 | ||
261 | ||
262 | /************************************************* | |
263 | * Client entry point * | |
264 | *************************************************/ | |
265 | ||
266 | /* For interface, see auths/README */ | |
267 | ||
268 | int | |
269 | auth_spa_client( | |
270 | auth_instance *ablock, /* authenticator block */ | |
251b9eb4 | 271 | void * sx, /* connection */ |
0756eb3c PH |
272 | int timeout, /* command timeout */ |
273 | uschar *buffer, /* buffer for reading response */ | |
274 | int buffsize) /* size of buffer */ | |
275 | { | |
4e910c01 JH |
276 | auth_spa_options_block *ob = |
277 | (auth_spa_options_block *)(ablock->options_block); | |
278 | SPAAuthRequest request; | |
279 | SPAAuthChallenge challenge; | |
280 | SPAAuthResponse response; | |
281 | char msgbuf[2048]; | |
282 | char *domain = NULL; | |
283 | char *username, *password; | |
284 | ||
285 | /* Code added by PH to expand the options */ | |
286 | ||
287 | *buffer = 0; /* Default no message when cancelled */ | |
288 | ||
289 | if (!(username = CS expand_string(ob->spa_username))) | |
290 | { | |
8768d548 | 291 | if (f.expand_string_forcedfail) return CANCELLED; |
4e910c01 JH |
292 | string_format(buffer, buffsize, "expansion of \"%s\" failed in %s " |
293 | "authenticator: %s", ob->spa_username, ablock->name, | |
294 | expand_string_message); | |
295 | return ERROR; | |
296 | } | |
297 | ||
298 | if (!(password = CS expand_string(ob->spa_password))) | |
299 | { | |
8768d548 | 300 | if (f.expand_string_forcedfail) return CANCELLED; |
4e910c01 JH |
301 | string_format(buffer, buffsize, "expansion of \"%s\" failed in %s " |
302 | "authenticator: %s", ob->spa_password, ablock->name, | |
303 | expand_string_message); | |
304 | return ERROR; | |
305 | } | |
306 | ||
307 | if (ob->spa_domain) | |
4e910c01 JH |
308 | if (!(domain = CS expand_string(ob->spa_domain))) |
309 | { | |
8768d548 | 310 | if (f.expand_string_forcedfail) return CANCELLED; |
4e910c01 JH |
311 | string_format(buffer, buffsize, "expansion of \"%s\" failed in %s " |
312 | "authenticator: %s", ob->spa_domain, ablock->name, | |
313 | expand_string_message); | |
314 | return ERROR; | |
315 | } | |
4e910c01 JH |
316 | |
317 | /* Original code */ | |
318 | ||
251b9eb4 | 319 | if (smtp_write_command(sx, SCMD_FLUSH, "AUTH %s\r\n", ablock->public_name) < 0) |
4e910c01 JH |
320 | return FAIL_SEND; |
321 | ||
322 | /* wait for the 3XX OK message */ | |
251b9eb4 | 323 | if (!smtp_read_response(sx, US buffer, buffsize, '3', timeout)) |
4e910c01 JH |
324 | return FAIL; |
325 | ||
326 | DSPA("\n\n%s authenticator: using domain %s\n\n", ablock->name, domain); | |
327 | ||
328 | spa_build_auth_request (&request, CS username, domain); | |
329 | spa_bits_to_base64 (US msgbuf, (unsigned char*)&request, | |
330 | spa_request_length(&request)); | |
331 | ||
332 | DSPA("\n\n%s authenticator: sending request (%s)\n\n", ablock->name, msgbuf); | |
333 | ||
334 | /* send the encrypted password */ | |
251b9eb4 | 335 | if (smtp_write_command(sx, SCMD_FLUSH, "%s\r\n", msgbuf) < 0) |
4e910c01 JH |
336 | return FAIL_SEND; |
337 | ||
338 | /* wait for the auth challenge */ | |
251b9eb4 | 339 | if (!smtp_read_response(sx, US buffer, buffsize, '3', timeout)) |
4e910c01 JH |
340 | return FAIL; |
341 | ||
342 | /* convert the challenge into the challenge struct */ | |
343 | DSPA("\n\n%s authenticator: challenge (%s)\n\n", ablock->name, buffer + 4); | |
5903c6ff | 344 | spa_base64_to_bits (CS (&challenge), sizeof(challenge), CCS (buffer + 4)); |
4e910c01 JH |
345 | |
346 | spa_build_auth_response (&challenge, &response, CS username, CS password); | |
347 | spa_bits_to_base64 (US msgbuf, (unsigned char*)&response, | |
348 | spa_request_length(&response)); | |
349 | DSPA("\n\n%s authenticator: challenge response (%s)\n\n", ablock->name, msgbuf); | |
350 | ||
351 | /* send the challenge response */ | |
251b9eb4 | 352 | if (smtp_write_command(sx, SCMD_FLUSH, "%s\r\n", msgbuf) < 0) |
4e910c01 JH |
353 | return FAIL_SEND; |
354 | ||
355 | /* If we receive a success response from the server, authentication | |
356 | has succeeded. There may be more data to send, but is there any point | |
357 | in provoking an error here? */ | |
358 | ||
251b9eb4 | 359 | if (smtp_read_response(sx, US buffer, buffsize, '2', timeout)) |
4e910c01 JH |
360 | return OK; |
361 | ||
362 | /* Not a success response. If errno != 0 there is some kind of transmission | |
363 | error. Otherwise, check the response code in the buffer. If it starts with | |
364 | '3', more data is expected. */ | |
365 | ||
366 | if (errno != 0 || buffer[0] != '3') | |
367 | return FAIL; | |
368 | ||
369 | return FAIL; | |
0756eb3c PH |
370 | } |
371 | ||
d185889f | 372 | #endif /*!MACRO_PREDEF*/ |
0756eb3c | 373 | /* End of spa.c */ |