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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 */ |
1e1ddfac | 6 | /* Copyright (c) The Exim Maintainers 2020 */ |
0756eb3c PH |
7 | /* See the file NOTICE for conditions of use and distribution. */ |
8 | ||
9 | /* This file, which provides support for Microsoft's Secure Password | |
10 | Authentication, was contributed by Marc Prud'hommeaux. Tom Kistner added SPA | |
11 | server support. I (PH) have only modified it in very trivial ways. | |
12 | ||
13 | References: | |
14 | http://www.innovation.ch/java/ntlm.html | |
15 | http://www.kuro5hin.org/story/2002/4/28/1436/66154 | |
55c75993 | 16 | http://download.microsoft.com/download/9/5/e/95ef66af-9026-4bb0-a41d-a4f81802d92c/%5bMS-SMTP%5d.pdf |
0756eb3c PH |
17 | |
18 | * It seems that some systems have existing but different definitions of some | |
19 | * of the following types. I received a complaint about "int16" causing | |
20 | * compilation problems. So I (PH) have renamed them all, to be on the safe | |
21 | * side, by adding 'x' on the end. See auths/auth-spa.h. | |
22 | ||
23 | * typedef signed short int16; | |
24 | * typedef unsigned short uint16; | |
25 | * typedef unsigned uint32; | |
26 | * typedef unsigned char uint8; | |
27 | ||
16ff981e PH |
28 | 07-August-2003: PH: Patched up the code to avoid assert bombouts for stupid |
29 | input data. Find appropriate comment by grepping for "PH". | |
30 | 16-October-2006: PH: Added a call to auth_check_serv_cond() at the end | |
55c75993 | 31 | 05-June-2010: PP: handle SASL initial response |
0756eb3c PH |
32 | */ |
33 | ||
34 | ||
35 | #include "../exim.h" | |
36 | #include "spa.h" | |
37 | ||
38 | /* #define DEBUG_SPA */ | |
39 | ||
40 | #ifdef DEBUG_SPA | |
41 | #define DSPA(x,y,z) debug_printf(x,y,z) | |
42 | #else | |
43 | #define DSPA(x,y,z) | |
44 | #endif | |
45 | ||
46 | /* Options specific to the spa authentication mechanism. */ | |
47 | ||
48 | optionlist auth_spa_options[] = { | |
49 | { "client_domain", opt_stringptr, | |
13a4b4c1 | 50 | OPT_OFF(auth_spa_options_block, spa_domain) }, |
0756eb3c | 51 | { "client_password", opt_stringptr, |
13a4b4c1 | 52 | OPT_OFF(auth_spa_options_block, spa_password) }, |
0756eb3c | 53 | { "client_username", opt_stringptr, |
13a4b4c1 | 54 | OPT_OFF(auth_spa_options_block, spa_username) }, |
0756eb3c | 55 | { "server_password", opt_stringptr, |
13a4b4c1 | 56 | OPT_OFF(auth_spa_options_block, spa_serverpassword) } |
0756eb3c PH |
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. */ | |
61 | ||
62 | int auth_spa_options_count = | |
63 | sizeof(auth_spa_options)/sizeof(optionlist); | |
64 | ||
4c04137d | 65 | /* Default private options block for the condition authentication method. */ |
0756eb3c PH |
66 | |
67 | auth_spa_options_block auth_spa_option_defaults = { | |
68 | NULL, /* spa_password */ | |
69 | NULL, /* spa_username */ | |
70 | NULL, /* spa_domain */ | |
71 | NULL /* spa_serverpassword (for server side use) */ | |
72 | }; | |
73 | ||
74 | ||
d185889f JH |
75 | #ifdef MACRO_PREDEF |
76 | ||
77 | /* Dummy values */ | |
78 | void auth_spa_init(auth_instance *ablock) {} | |
79 | int auth_spa_server(auth_instance *ablock, uschar *data) {return 0;} | |
251b9eb4 JH |
80 | int auth_spa_client(auth_instance *ablock, void * sx, int timeout, |
81 | uschar *buffer, int buffsize) {return 0;} | |
d185889f JH |
82 | |
83 | #else /*!MACRO_PREDEF*/ | |
84 | ||
85 | ||
86 | ||
87 | ||
0756eb3c PH |
88 | /************************************************* |
89 | * Initialization entry point * | |
90 | *************************************************/ | |
91 | ||
92 | /* Called for each instance, after its options have been read, to | |
93 | enable consistency checks to be done, or anything else that needs | |
94 | to be set up. */ | |
95 | ||
96 | void | |
97 | auth_spa_init(auth_instance *ablock) | |
98 | { | |
99 | auth_spa_options_block *ob = | |
100 | (auth_spa_options_block *)(ablock->options_block); | |
101 | ||
102 | /* The public name defaults to the authenticator name */ | |
103 | ||
104 | if (ablock->public_name == NULL) ablock->public_name = ablock->name; | |
105 | ||
106 | /* Both username and password must be set for a client */ | |
107 | ||
108 | if ((ob->spa_username == NULL) != (ob->spa_password == NULL)) | |
109 | log_write(0, LOG_PANIC_DIE|LOG_CONFIG_FOR, "%s authenticator:\n " | |
110 | "one of client_username and client_password cannot be set without " | |
111 | "the other", ablock->name); | |
112 | ablock->client = ob->spa_username != NULL; | |
113 | ||
114 | /* For a server we have just one option */ | |
115 | ||
116 | ablock->server = ob->spa_serverpassword != NULL; | |
117 | } | |
118 | ||
119 | ||
120 | ||
121 | /************************************************* | |
122 | * Server entry point * | |
123 | *************************************************/ | |
124 | ||
125 | /* For interface, see auths/README */ | |
126 | ||
5903c6ff | 127 | #define CVAL(buf,pos) ((US (buf))[pos]) |
0756eb3c PH |
128 | #define PVAL(buf,pos) ((unsigned)CVAL(buf,pos)) |
129 | #define SVAL(buf,pos) (PVAL(buf,pos)|PVAL(buf,(pos)+1)<<8) | |
130 | #define IVAL(buf,pos) (SVAL(buf,pos)|SVAL(buf,(pos)+2)<<16) | |
131 | ||
132 | int | |
133 | auth_spa_server(auth_instance *ablock, uschar *data) | |
134 | { | |
135 | auth_spa_options_block *ob = (auth_spa_options_block *)(ablock->options_block); | |
136 | uint8x lmRespData[24]; | |
137 | uint8x ntRespData[24]; | |
138 | SPAAuthRequest request; | |
139 | SPAAuthChallenge challenge; | |
140 | SPAAuthResponse response; | |
141 | SPAAuthResponse *responseptr = &response; | |
142 | uschar msgbuf[2048]; | |
57aa14b2 | 143 | uschar *clearpass, *s; |
0756eb3c | 144 | |
55c75993 PP |
145 | /* send a 334, MS Exchange style, and grab the client's request, |
146 | unless we already have it via an initial response. */ | |
0756eb3c | 147 | |
99dbdcf4 | 148 | if (!*data && auth_get_no64_data(&data, US"NTLM supported") != OK) |
0756eb3c | 149 | return FAIL; |
0756eb3c | 150 | |
99dbdcf4 | 151 | if (spa_base64_to_bits(CS &request, sizeof(request), CCS data) < 0) |
0756eb3c PH |
152 | { |
153 | DEBUG(D_auth) debug_printf("auth_spa_server(): bad base64 data in " | |
99dbdcf4 | 154 | "request: %s\n", data); |
0756eb3c PH |
155 | return FAIL; |
156 | } | |
157 | ||
158 | /* create a challenge and send it back */ | |
159 | ||
99dbdcf4 JH |
160 | spa_build_auth_challenge(&request, &challenge); |
161 | spa_bits_to_base64(msgbuf, US &challenge, spa_request_length(&challenge)); | |
0756eb3c PH |
162 | |
163 | if (auth_get_no64_data(&data, msgbuf) != OK) | |
0756eb3c | 164 | return FAIL; |
0756eb3c PH |
165 | |
166 | /* dump client response */ | |
99dbdcf4 | 167 | if (spa_base64_to_bits(CS &response, sizeof(response), CCS data) < 0) |
0756eb3c PH |
168 | { |
169 | DEBUG(D_auth) debug_printf("auth_spa_server(): bad base64 data in " | |
99dbdcf4 | 170 | "response: %s\n", data); |
0756eb3c PH |
171 | return FAIL; |
172 | } | |
173 | ||
0756eb3c PH |
174 | /*************************************************************** |
175 | PH 07-Aug-2003: The original code here was this: | |
176 | ||
177 | Ustrcpy(msgbuf, unicodeToString(((char*)responseptr) + | |
178 | IVAL(&responseptr->uUser.offset,0), | |
179 | SVAL(&responseptr->uUser.len,0)/2) ); | |
180 | ||
181 | However, if the response data is too long, unicodeToString bombs out on | |
182 | an assertion failure. It uses a 1024 fixed buffer. Bombing out is not a good | |
183 | idea. It's too messy to try to rework that function to return an error because | |
184 | it is called from a number of other places in the auth-spa.c module. Instead, | |
185 | since it is a very small function, I reproduce its code here, with a size check | |
186 | that causes failure if the size of msgbuf is exceeded. ****/ | |
187 | ||
188 | { | |
189 | int i; | |
99dbdcf4 | 190 | char * p = (CS responseptr) + IVAL(&responseptr->uUser.offset,0); |
0756eb3c PH |
191 | int len = SVAL(&responseptr->uUser.len,0)/2; |
192 | ||
57aa14b2 JH |
193 | if (p + len*2 >= CS (responseptr+1)) |
194 | { | |
195 | DEBUG(D_auth) | |
196 | debug_printf("auth_spa_server(): bad uUser spec in response\n"); | |
197 | return FAIL; | |
198 | } | |
199 | ||
0756eb3c PH |
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 | ||
99dbdcf4 | 224 | if (!(clearpass = expand_string(ob->spa_serverpassword))) |
8768d548 | 225 | if (f.expand_string_forcedfail) |
0756eb3c PH |
226 | { |
227 | DEBUG(D_auth) debug_printf("auth_spa_server(): forced failure while " | |
228 | "expanding spa_serverpassword\n"); | |
f68fe5f6 | 229 | return FAIL; |
0756eb3c PH |
230 | } |
231 | else | |
232 | { | |
233 | DEBUG(D_auth) debug_printf("auth_spa_server(): error while expanding " | |
234 | "spa_serverpassword: %s\n", expand_string_message); | |
f68fe5f6 | 235 | return DEFER; |
0756eb3c | 236 | } |
0756eb3c PH |
237 | |
238 | /* create local hash copy */ | |
239 | ||
99dbdcf4 JH |
240 | spa_smb_encrypt(clearpass, challenge.challengeData, lmRespData); |
241 | spa_smb_nt_encrypt(clearpass, challenge.challengeData, ntRespData); | |
0756eb3c PH |
242 | |
243 | /* compare NT hash (LM may not be available) */ | |
244 | ||
57aa14b2 JH |
245 | s = (US responseptr) + IVAL(&responseptr->ntResponse.offset,0); |
246 | if (s + 24 >= US (responseptr+1)) | |
247 | { | |
248 | DEBUG(D_auth) | |
249 | debug_printf("auth_spa_server(): bad ntRespData spec in response\n"); | |
250 | return FAIL; | |
251 | } | |
252 | ||
253 | if (memcmp(ntRespData, s, 24) == 0) | |
99dbdcf4 | 254 | return auth_check_serv_cond(ablock); /* success. we have a winner. */ |
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 | ||
99dbdcf4 JH |
328 | spa_build_auth_request(&request, CS username, domain); |
329 | spa_bits_to_base64(US msgbuf, US &request, spa_request_length(&request)); | |
4e910c01 JH |
330 | |
331 | DSPA("\n\n%s authenticator: sending request (%s)\n\n", ablock->name, msgbuf); | |
332 | ||
333 | /* send the encrypted password */ | |
251b9eb4 | 334 | if (smtp_write_command(sx, SCMD_FLUSH, "%s\r\n", msgbuf) < 0) |
4e910c01 JH |
335 | return FAIL_SEND; |
336 | ||
337 | /* wait for the auth challenge */ | |
251b9eb4 | 338 | if (!smtp_read_response(sx, US buffer, buffsize, '3', timeout)) |
4e910c01 JH |
339 | return FAIL; |
340 | ||
341 | /* convert the challenge into the challenge struct */ | |
342 | DSPA("\n\n%s authenticator: challenge (%s)\n\n", ablock->name, buffer + 4); | |
99dbdcf4 | 343 | spa_base64_to_bits(CS (&challenge), sizeof(challenge), CCS (buffer + 4)); |
4e910c01 | 344 | |
99dbdcf4 JH |
345 | spa_build_auth_response(&challenge, &response, CS username, CS password); |
346 | spa_bits_to_base64(US msgbuf, US &response, spa_request_length(&response)); | |
4e910c01 JH |
347 | DSPA("\n\n%s authenticator: challenge response (%s)\n\n", ablock->name, msgbuf); |
348 | ||
349 | /* send the challenge response */ | |
251b9eb4 | 350 | if (smtp_write_command(sx, SCMD_FLUSH, "%s\r\n", msgbuf) < 0) |
4e910c01 JH |
351 | return FAIL_SEND; |
352 | ||
353 | /* If we receive a success response from the server, authentication | |
354 | has succeeded. There may be more data to send, but is there any point | |
355 | in provoking an error here? */ | |
356 | ||
251b9eb4 | 357 | if (smtp_read_response(sx, US buffer, buffsize, '2', timeout)) |
4e910c01 JH |
358 | return OK; |
359 | ||
360 | /* Not a success response. If errno != 0 there is some kind of transmission | |
361 | error. Otherwise, check the response code in the buffer. If it starts with | |
362 | '3', more data is expected. */ | |
363 | ||
364 | if (errno != 0 || buffer[0] != '3') | |
365 | return FAIL; | |
366 | ||
367 | return FAIL; | |
0756eb3c PH |
368 | } |
369 | ||
d185889f | 370 | #endif /*!MACRO_PREDEF*/ |
0756eb3c | 371 | /* End of spa.c */ |