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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; |
a04174dc | 144 | unsigned off; |
0756eb3c | 145 | |
55c75993 PP |
146 | /* send a 334, MS Exchange style, and grab the client's request, |
147 | unless we already have it via an initial response. */ | |
0756eb3c | 148 | |
99dbdcf4 | 149 | if (!*data && auth_get_no64_data(&data, US"NTLM supported") != OK) |
0756eb3c | 150 | return FAIL; |
0756eb3c | 151 | |
99dbdcf4 | 152 | if (spa_base64_to_bits(CS &request, sizeof(request), CCS data) < 0) |
0756eb3c PH |
153 | { |
154 | DEBUG(D_auth) debug_printf("auth_spa_server(): bad base64 data in " | |
99dbdcf4 | 155 | "request: %s\n", data); |
0756eb3c PH |
156 | return FAIL; |
157 | } | |
158 | ||
159 | /* create a challenge and send it back */ | |
160 | ||
99dbdcf4 JH |
161 | spa_build_auth_challenge(&request, &challenge); |
162 | spa_bits_to_base64(msgbuf, US &challenge, spa_request_length(&challenge)); | |
0756eb3c PH |
163 | |
164 | if (auth_get_no64_data(&data, msgbuf) != OK) | |
0756eb3c | 165 | return FAIL; |
0756eb3c PH |
166 | |
167 | /* dump client response */ | |
99dbdcf4 | 168 | if (spa_base64_to_bits(CS &response, sizeof(response), CCS data) < 0) |
0756eb3c PH |
169 | { |
170 | DEBUG(D_auth) debug_printf("auth_spa_server(): bad base64 data in " | |
99dbdcf4 | 171 | "response: %s\n", data); |
0756eb3c PH |
172 | return FAIL; |
173 | } | |
174 | ||
0756eb3c PH |
175 | /*************************************************************** |
176 | PH 07-Aug-2003: The original code here was this: | |
177 | ||
178 | Ustrcpy(msgbuf, unicodeToString(((char*)responseptr) + | |
179 | IVAL(&responseptr->uUser.offset,0), | |
180 | SVAL(&responseptr->uUser.len,0)/2) ); | |
181 | ||
182 | However, if the response data is too long, unicodeToString bombs out on | |
183 | an assertion failure. It uses a 1024 fixed buffer. Bombing out is not a good | |
184 | idea. It's too messy to try to rework that function to return an error because | |
185 | it is called from a number of other places in the auth-spa.c module. Instead, | |
186 | since it is a very small function, I reproduce its code here, with a size check | |
187 | that causes failure if the size of msgbuf is exceeded. ****/ | |
188 | ||
189 | { | |
190 | int i; | |
a04174dc | 191 | char * p; |
0756eb3c PH |
192 | int len = SVAL(&responseptr->uUser.len,0)/2; |
193 | ||
a04174dc JH |
194 | if ( (off = IVAL(&responseptr->uUser.offset,0)) >= sizeof(SPAAuthResponse) |
195 | || len >= sizeof(responseptr->buffer)/2 | |
196 | || (p = (CS responseptr) + off) + len*2 >= CS (responseptr+1) | |
197 | ) | |
57aa14b2 JH |
198 | { |
199 | DEBUG(D_auth) | |
200 | debug_printf("auth_spa_server(): bad uUser spec in response\n"); | |
201 | return FAIL; | |
202 | } | |
203 | ||
0756eb3c PH |
204 | if (len + 1 >= sizeof(msgbuf)) return FAIL; |
205 | for (i = 0; i < len; ++i) | |
206 | { | |
207 | msgbuf[i] = *p & 0x7f; | |
208 | p += 2; | |
209 | } | |
210 | msgbuf[i] = 0; | |
211 | } | |
212 | ||
213 | /***************************************************************/ | |
214 | ||
f78eb7c6 | 215 | /* Put the username in $auth1 and $1. The former is now the preferred variable; |
f68fe5f6 PP |
216 | the latter is the original variable. These have to be out of stack memory, and |
217 | need to be available once known even if not authenticated, for error messages | |
218 | (server_set_id, which only makes it to authenticated_id if we return OK) */ | |
f78eb7c6 | 219 | |
f68fe5f6 | 220 | auth_vars[0] = expand_nstring[1] = string_copy(msgbuf); |
0756eb3c PH |
221 | expand_nlength[1] = Ustrlen(msgbuf); |
222 | expand_nmax = 1; | |
223 | ||
f78eb7c6 PH |
224 | debug_print_string(ablock->server_debug_string); /* customized debug */ |
225 | ||
0756eb3c PH |
226 | /* look up password */ |
227 | ||
99dbdcf4 | 228 | if (!(clearpass = expand_string(ob->spa_serverpassword))) |
8768d548 | 229 | if (f.expand_string_forcedfail) |
0756eb3c PH |
230 | { |
231 | DEBUG(D_auth) debug_printf("auth_spa_server(): forced failure while " | |
232 | "expanding spa_serverpassword\n"); | |
f68fe5f6 | 233 | return FAIL; |
0756eb3c PH |
234 | } |
235 | else | |
236 | { | |
237 | DEBUG(D_auth) debug_printf("auth_spa_server(): error while expanding " | |
238 | "spa_serverpassword: %s\n", expand_string_message); | |
f68fe5f6 | 239 | return DEFER; |
0756eb3c | 240 | } |
0756eb3c PH |
241 | |
242 | /* create local hash copy */ | |
243 | ||
99dbdcf4 JH |
244 | spa_smb_encrypt(clearpass, challenge.challengeData, lmRespData); |
245 | spa_smb_nt_encrypt(clearpass, challenge.challengeData, ntRespData); | |
0756eb3c PH |
246 | |
247 | /* compare NT hash (LM may not be available) */ | |
248 | ||
a04174dc JH |
249 | off = IVAL(&responseptr->ntResponse.offset,0); |
250 | if (off >= sizeof(SPAAuthResponse) - 24) | |
57aa14b2 JH |
251 | { |
252 | DEBUG(D_auth) | |
253 | debug_printf("auth_spa_server(): bad ntRespData spec in response\n"); | |
254 | return FAIL; | |
255 | } | |
a04174dc | 256 | s = (US responseptr) + off; |
57aa14b2 JH |
257 | |
258 | if (memcmp(ntRespData, s, 24) == 0) | |
99dbdcf4 | 259 | return auth_check_serv_cond(ablock); /* success. we have a winner. */ |
16ff981e PH |
260 | |
261 | /* Expand server_condition as an authorization check (PH) */ | |
0756eb3c | 262 | |
f68fe5f6 | 263 | return FAIL; |
0756eb3c PH |
264 | } |
265 | ||
266 | ||
267 | /************************************************* | |
268 | * Client entry point * | |
269 | *************************************************/ | |
270 | ||
271 | /* For interface, see auths/README */ | |
272 | ||
273 | int | |
274 | auth_spa_client( | |
275 | auth_instance *ablock, /* authenticator block */ | |
251b9eb4 | 276 | void * sx, /* connection */ |
0756eb3c PH |
277 | int timeout, /* command timeout */ |
278 | uschar *buffer, /* buffer for reading response */ | |
279 | int buffsize) /* size of buffer */ | |
280 | { | |
4e910c01 JH |
281 | auth_spa_options_block *ob = |
282 | (auth_spa_options_block *)(ablock->options_block); | |
283 | SPAAuthRequest request; | |
284 | SPAAuthChallenge challenge; | |
285 | SPAAuthResponse response; | |
286 | char msgbuf[2048]; | |
287 | char *domain = NULL; | |
288 | char *username, *password; | |
289 | ||
290 | /* Code added by PH to expand the options */ | |
291 | ||
292 | *buffer = 0; /* Default no message when cancelled */ | |
293 | ||
294 | if (!(username = CS expand_string(ob->spa_username))) | |
295 | { | |
8768d548 | 296 | if (f.expand_string_forcedfail) return CANCELLED; |
4e910c01 JH |
297 | string_format(buffer, buffsize, "expansion of \"%s\" failed in %s " |
298 | "authenticator: %s", ob->spa_username, ablock->name, | |
299 | expand_string_message); | |
300 | return ERROR; | |
301 | } | |
302 | ||
303 | if (!(password = CS expand_string(ob->spa_password))) | |
304 | { | |
8768d548 | 305 | if (f.expand_string_forcedfail) return CANCELLED; |
4e910c01 JH |
306 | string_format(buffer, buffsize, "expansion of \"%s\" failed in %s " |
307 | "authenticator: %s", ob->spa_password, ablock->name, | |
308 | expand_string_message); | |
309 | return ERROR; | |
310 | } | |
311 | ||
312 | if (ob->spa_domain) | |
4e910c01 JH |
313 | if (!(domain = CS expand_string(ob->spa_domain))) |
314 | { | |
8768d548 | 315 | if (f.expand_string_forcedfail) return CANCELLED; |
4e910c01 JH |
316 | string_format(buffer, buffsize, "expansion of \"%s\" failed in %s " |
317 | "authenticator: %s", ob->spa_domain, ablock->name, | |
318 | expand_string_message); | |
319 | return ERROR; | |
320 | } | |
4e910c01 JH |
321 | |
322 | /* Original code */ | |
323 | ||
251b9eb4 | 324 | if (smtp_write_command(sx, SCMD_FLUSH, "AUTH %s\r\n", ablock->public_name) < 0) |
4e910c01 JH |
325 | return FAIL_SEND; |
326 | ||
327 | /* wait for the 3XX OK message */ | |
251b9eb4 | 328 | if (!smtp_read_response(sx, US buffer, buffsize, '3', timeout)) |
4e910c01 JH |
329 | return FAIL; |
330 | ||
331 | DSPA("\n\n%s authenticator: using domain %s\n\n", ablock->name, domain); | |
332 | ||
99dbdcf4 JH |
333 | spa_build_auth_request(&request, CS username, domain); |
334 | spa_bits_to_base64(US msgbuf, US &request, spa_request_length(&request)); | |
4e910c01 JH |
335 | |
336 | DSPA("\n\n%s authenticator: sending request (%s)\n\n", ablock->name, msgbuf); | |
337 | ||
338 | /* send the encrypted password */ | |
251b9eb4 | 339 | if (smtp_write_command(sx, SCMD_FLUSH, "%s\r\n", msgbuf) < 0) |
4e910c01 JH |
340 | return FAIL_SEND; |
341 | ||
342 | /* wait for the auth challenge */ | |
251b9eb4 | 343 | if (!smtp_read_response(sx, US buffer, buffsize, '3', timeout)) |
4e910c01 JH |
344 | return FAIL; |
345 | ||
346 | /* convert the challenge into the challenge struct */ | |
347 | DSPA("\n\n%s authenticator: challenge (%s)\n\n", ablock->name, buffer + 4); | |
99dbdcf4 | 348 | spa_base64_to_bits(CS (&challenge), sizeof(challenge), CCS (buffer + 4)); |
4e910c01 | 349 | |
99dbdcf4 JH |
350 | spa_build_auth_response(&challenge, &response, CS username, CS password); |
351 | spa_bits_to_base64(US msgbuf, US &response, spa_request_length(&response)); | |
4e910c01 JH |
352 | DSPA("\n\n%s authenticator: challenge response (%s)\n\n", ablock->name, msgbuf); |
353 | ||
354 | /* send the challenge response */ | |
251b9eb4 | 355 | if (smtp_write_command(sx, SCMD_FLUSH, "%s\r\n", msgbuf) < 0) |
4e910c01 JH |
356 | return FAIL_SEND; |
357 | ||
358 | /* If we receive a success response from the server, authentication | |
359 | has succeeded. There may be more data to send, but is there any point | |
360 | in provoking an error here? */ | |
361 | ||
251b9eb4 | 362 | if (smtp_read_response(sx, US buffer, buffsize, '2', timeout)) |
4e910c01 JH |
363 | return OK; |
364 | ||
365 | /* Not a success response. If errno != 0 there is some kind of transmission | |
366 | error. Otherwise, check the response code in the buffer. If it starts with | |
367 | '3', more data is expected. */ | |
368 | ||
369 | if (errno != 0 || buffer[0] != '3') | |
370 | return FAIL; | |
371 | ||
372 | return FAIL; | |
0756eb3c PH |
373 | } |
374 | ||
d185889f | 375 | #endif /*!MACRO_PREDEF*/ |
0756eb3c | 376 | /* End of spa.c */ |