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16ff981e | 1 | /* $Cambridge: exim/src/src/auths/spa.c,v 1.8 2006/10/16 15:44:36 ph10 Exp $ */ |
0756eb3c PH |
2 | |
3 | /************************************************* | |
4 | * Exim - an Internet mail transport agent * | |
5 | *************************************************/ | |
6 | ||
d7d7b7b9 | 7 | /* Copyright (c) University of Cambridge 1995 - 2006 */ |
0756eb3c PH |
8 | /* See the file NOTICE for conditions of use and distribution. */ |
9 | ||
10 | /* This file, which provides support for Microsoft's Secure Password | |
11 | Authentication, was contributed by Marc Prud'hommeaux. Tom Kistner added SPA | |
12 | server support. I (PH) have only modified it in very trivial ways. | |
13 | ||
14 | References: | |
15 | http://www.innovation.ch/java/ntlm.html | |
16 | http://www.kuro5hin.org/story/2002/4/28/1436/66154 | |
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 | |
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, | |
49 | (void *)(offsetof(auth_spa_options_block, spa_domain)) }, | |
50 | { "client_password", opt_stringptr, | |
51 | (void *)(offsetof(auth_spa_options_block, spa_password)) }, | |
52 | { "client_username", opt_stringptr, | |
53 | (void *)(offsetof(auth_spa_options_block, spa_username)) }, | |
54 | { "server_password", opt_stringptr, | |
55 | (void *)(offsetof(auth_spa_options_block, spa_serverpassword)) } | |
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 | ||
64 | /* Default private options block for the contidion authentication method. */ | |
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 | ||
74 | /************************************************* | |
75 | * Initialization entry point * | |
76 | *************************************************/ | |
77 | ||
78 | /* Called for each instance, after its options have been read, to | |
79 | enable consistency checks to be done, or anything else that needs | |
80 | to be set up. */ | |
81 | ||
82 | void | |
83 | auth_spa_init(auth_instance *ablock) | |
84 | { | |
85 | auth_spa_options_block *ob = | |
86 | (auth_spa_options_block *)(ablock->options_block); | |
87 | ||
88 | /* The public name defaults to the authenticator name */ | |
89 | ||
90 | if (ablock->public_name == NULL) ablock->public_name = ablock->name; | |
91 | ||
92 | /* Both username and password must be set for a client */ | |
93 | ||
94 | if ((ob->spa_username == NULL) != (ob->spa_password == NULL)) | |
95 | log_write(0, LOG_PANIC_DIE|LOG_CONFIG_FOR, "%s authenticator:\n " | |
96 | "one of client_username and client_password cannot be set without " | |
97 | "the other", ablock->name); | |
98 | ablock->client = ob->spa_username != NULL; | |
99 | ||
100 | /* For a server we have just one option */ | |
101 | ||
102 | ablock->server = ob->spa_serverpassword != NULL; | |
103 | } | |
104 | ||
105 | ||
106 | ||
107 | /************************************************* | |
108 | * Server entry point * | |
109 | *************************************************/ | |
110 | ||
111 | /* For interface, see auths/README */ | |
112 | ||
113 | #define CVAL(buf,pos) (((unsigned char *)(buf))[pos]) | |
114 | #define PVAL(buf,pos) ((unsigned)CVAL(buf,pos)) | |
115 | #define SVAL(buf,pos) (PVAL(buf,pos)|PVAL(buf,(pos)+1)<<8) | |
116 | #define IVAL(buf,pos) (SVAL(buf,pos)|SVAL(buf,(pos)+2)<<16) | |
117 | ||
118 | int | |
119 | auth_spa_server(auth_instance *ablock, uschar *data) | |
120 | { | |
121 | auth_spa_options_block *ob = (auth_spa_options_block *)(ablock->options_block); | |
122 | uint8x lmRespData[24]; | |
123 | uint8x ntRespData[24]; | |
124 | SPAAuthRequest request; | |
125 | SPAAuthChallenge challenge; | |
126 | SPAAuthResponse response; | |
127 | SPAAuthResponse *responseptr = &response; | |
128 | uschar msgbuf[2048]; | |
129 | uschar *clearpass; | |
130 | ||
131 | /* send a 334, MS Exchange style, and grab the client's request */ | |
132 | ||
133 | if (auth_get_no64_data(&data, US"NTLM supported") != OK) | |
134 | { | |
135 | /* something borked */ | |
136 | return FAIL; | |
137 | } | |
138 | ||
85b87bc2 | 139 | if (spa_base64_to_bits((char *)(&request), sizeof(request), (const char *)(data)) < 0) |
0756eb3c PH |
140 | { |
141 | DEBUG(D_auth) debug_printf("auth_spa_server(): bad base64 data in " | |
142 | "request: %s\n", data); | |
143 | return FAIL; | |
144 | } | |
145 | ||
146 | /* create a challenge and send it back */ | |
147 | ||
148 | spa_build_auth_challenge(&request,&challenge); | |
149 | spa_bits_to_base64 (msgbuf, (unsigned char*)&challenge, | |
150 | spa_request_length(&challenge)); | |
151 | ||
152 | if (auth_get_no64_data(&data, msgbuf) != OK) | |
153 | { | |
154 | /* something borked */ | |
155 | return FAIL; | |
156 | } | |
157 | ||
158 | /* dump client response */ | |
85b87bc2 | 159 | if (spa_base64_to_bits((char *)(&response), sizeof(response), (const char *)(data)) < 0) |
0756eb3c PH |
160 | { |
161 | DEBUG(D_auth) debug_printf("auth_spa_server(): bad base64 data in " | |
162 | "response: %s\n", data); | |
163 | return FAIL; | |
164 | } | |
165 | ||
0756eb3c PH |
166 | /*************************************************************** |
167 | PH 07-Aug-2003: The original code here was this: | |
168 | ||
169 | Ustrcpy(msgbuf, unicodeToString(((char*)responseptr) + | |
170 | IVAL(&responseptr->uUser.offset,0), | |
171 | SVAL(&responseptr->uUser.len,0)/2) ); | |
172 | ||
173 | However, if the response data is too long, unicodeToString bombs out on | |
174 | an assertion failure. It uses a 1024 fixed buffer. Bombing out is not a good | |
175 | idea. It's too messy to try to rework that function to return an error because | |
176 | it is called from a number of other places in the auth-spa.c module. Instead, | |
177 | since it is a very small function, I reproduce its code here, with a size check | |
178 | that causes failure if the size of msgbuf is exceeded. ****/ | |
179 | ||
180 | { | |
181 | int i; | |
182 | char *p = ((char*)responseptr) + IVAL(&responseptr->uUser.offset,0); | |
183 | int len = SVAL(&responseptr->uUser.len,0)/2; | |
184 | ||
185 | if (len + 1 >= sizeof(msgbuf)) return FAIL; | |
186 | for (i = 0; i < len; ++i) | |
187 | { | |
188 | msgbuf[i] = *p & 0x7f; | |
189 | p += 2; | |
190 | } | |
191 | msgbuf[i] = 0; | |
192 | } | |
193 | ||
194 | /***************************************************************/ | |
195 | ||
f78eb7c6 PH |
196 | /* Put the username in $auth1 and $1. The former is now the preferred variable; |
197 | the latter is the original variable. */ | |
198 | ||
199 | auth_vars[0] = expand_nstring[1] = msgbuf; | |
0756eb3c PH |
200 | expand_nlength[1] = Ustrlen(msgbuf); |
201 | expand_nmax = 1; | |
202 | ||
f78eb7c6 PH |
203 | debug_print_string(ablock->server_debug_string); /* customized debug */ |
204 | ||
0756eb3c PH |
205 | /* look up password */ |
206 | ||
207 | clearpass = expand_string(ob->spa_serverpassword); | |
208 | if (clearpass == NULL) | |
209 | { | |
210 | if (expand_string_forcedfail) | |
211 | { | |
212 | DEBUG(D_auth) debug_printf("auth_spa_server(): forced failure while " | |
213 | "expanding spa_serverpassword\n"); | |
214 | return FAIL; | |
215 | } | |
216 | else | |
217 | { | |
218 | DEBUG(D_auth) debug_printf("auth_spa_server(): error while expanding " | |
219 | "spa_serverpassword: %s\n", expand_string_message); | |
220 | return DEFER; | |
221 | } | |
222 | } | |
223 | ||
224 | /* create local hash copy */ | |
225 | ||
226 | spa_smb_encrypt (clearpass, challenge.challengeData, lmRespData); | |
227 | spa_smb_nt_encrypt (clearpass, challenge.challengeData, ntRespData); | |
228 | ||
229 | /* compare NT hash (LM may not be available) */ | |
230 | ||
231 | if (memcmp(ntRespData, | |
232 | ((unsigned char*)responseptr)+IVAL(&responseptr->ntResponse.offset,0), | |
233 | 24) == 0) | |
234 | /* success. we have a winner. */ | |
16ff981e PH |
235 | |
236 | /* Expand server_condition as an authorization check (PH) */ | |
237 | return auth_check_serv_cond(ablock); | |
0756eb3c PH |
238 | |
239 | return FAIL; | |
240 | } | |
241 | ||
242 | ||
243 | /************************************************* | |
244 | * Client entry point * | |
245 | *************************************************/ | |
246 | ||
247 | /* For interface, see auths/README */ | |
248 | ||
249 | int | |
250 | auth_spa_client( | |
251 | auth_instance *ablock, /* authenticator block */ | |
252 | smtp_inblock *inblock, /* connection inblock */ | |
253 | smtp_outblock *outblock, /* connection outblock */ | |
254 | int timeout, /* command timeout */ | |
255 | uschar *buffer, /* buffer for reading response */ | |
256 | int buffsize) /* size of buffer */ | |
257 | { | |
258 | auth_spa_options_block *ob = | |
259 | (auth_spa_options_block *)(ablock->options_block); | |
260 | SPAAuthRequest request; | |
261 | SPAAuthChallenge challenge; | |
262 | SPAAuthResponse response; | |
263 | char msgbuf[2048]; | |
264 | char *domain = NULL; | |
265 | char *username, *password; | |
266 | ||
0756eb3c PH |
267 | /* Code added by PH to expand the options */ |
268 | ||
4730f942 PH |
269 | *buffer = 0; /* Default no message when cancelled */ |
270 | ||
0756eb3c PH |
271 | username = CS expand_string(ob->spa_username); |
272 | if (username == NULL) | |
273 | { | |
b1206957 | 274 | if (expand_string_forcedfail) return CANCELLED; |
0756eb3c PH |
275 | string_format(buffer, buffsize, "expansion of \"%s\" failed in %s " |
276 | "authenticator: %s", ob->spa_username, ablock->name, | |
277 | expand_string_message); | |
278 | return ERROR; | |
279 | } | |
280 | ||
281 | password = CS expand_string(ob->spa_password); | |
282 | if (password == NULL) | |
283 | { | |
b1206957 | 284 | if (expand_string_forcedfail) return CANCELLED; |
0756eb3c PH |
285 | string_format(buffer, buffsize, "expansion of \"%s\" failed in %s " |
286 | "authenticator: %s", ob->spa_password, ablock->name, | |
287 | expand_string_message); | |
288 | return ERROR; | |
289 | } | |
290 | ||
291 | if (ob->spa_domain != NULL) | |
292 | { | |
293 | domain = CS expand_string(ob->spa_domain); | |
294 | if (domain == NULL) | |
295 | { | |
b1206957 | 296 | if (expand_string_forcedfail) return CANCELLED; |
0756eb3c PH |
297 | string_format(buffer, buffsize, "expansion of \"%s\" failed in %s " |
298 | "authenticator: %s", ob->spa_domain, ablock->name, | |
299 | expand_string_message); | |
300 | return ERROR; | |
301 | } | |
302 | } | |
303 | ||
304 | /* Original code */ | |
305 | ||
b1206957 PH |
306 | if (smtp_write_command(outblock, FALSE, "AUTH %s\r\n", |
307 | ablock->public_name) < 0) | |
308 | return FAIL_SEND; | |
309 | ||
310 | /* wait for the 3XX OK message */ | |
311 | if (!smtp_read_response(inblock, (uschar *)buffer, buffsize, '3', timeout)) | |
312 | return FAIL; | |
313 | ||
0756eb3c PH |
314 | DSPA("\n\n%s authenticator: using domain %s\n\n", |
315 | ablock->name, domain); | |
316 | ||
317 | spa_build_auth_request (&request, CS username, domain); | |
318 | spa_bits_to_base64 (US msgbuf, (unsigned char*)&request, | |
319 | spa_request_length(&request)); | |
320 | ||
321 | DSPA("\n\n%s authenticator: sending request (%s)\n\n", ablock->name, | |
322 | msgbuf); | |
323 | ||
324 | /* send the encrypted password */ | |
325 | if (smtp_write_command(outblock, FALSE, "%s\r\n", msgbuf) < 0) | |
326 | return FAIL_SEND; | |
327 | ||
328 | /* wait for the auth challenge */ | |
329 | if (!smtp_read_response(inblock, (uschar *)buffer, buffsize, '3', timeout)) | |
330 | return FAIL; | |
331 | ||
332 | /* convert the challenge into the challenge struct */ | |
333 | DSPA("\n\n%s authenticator: challenge (%s)\n\n", | |
334 | ablock->name, buffer + 4); | |
85b87bc2 | 335 | spa_base64_to_bits ((char *)(&challenge), sizeof(challenge), (const char *)(buffer + 4)); |
0756eb3c PH |
336 | |
337 | spa_build_auth_response (&challenge, &response, | |
338 | CS username, CS password); | |
339 | spa_bits_to_base64 (US msgbuf, (unsigned char*)&response, | |
340 | spa_request_length(&response)); | |
341 | DSPA("\n\n%s authenticator: challenge response (%s)\n\n", ablock->name, | |
342 | msgbuf); | |
343 | ||
344 | /* send the challenge response */ | |
345 | if (smtp_write_command(outblock, FALSE, "%s\r\n", msgbuf) < 0) | |
346 | return FAIL_SEND; | |
347 | ||
348 | /* If we receive a success response from the server, authentication | |
349 | has succeeded. There may be more data to send, but is there any point | |
350 | in provoking an error here? */ | |
351 | if (smtp_read_response(inblock, US buffer, buffsize, '2', timeout)) | |
352 | return OK; | |
353 | ||
354 | /* Not a success response. If errno != 0 there is some kind of transmission | |
355 | error. Otherwise, check the response code in the buffer. If it starts with | |
356 | '3', more data is expected. */ | |
357 | if (errno != 0 || buffer[0] != '3') | |
358 | return FAIL; | |
359 | ||
360 | return FAIL; | |
361 | } | |
362 | ||
363 | /* End of spa.c */ |