1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) University of Cambridge 1995 - 2009 */
6 /* See the file NOTICE for conditions of use and distribution. */
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.
13 http://www.innovation.ch/java/ntlm.html
14 http://www.kuro5hin.org/story/2002/4/28/1436/66154
15 http://download.microsoft.com/download/9/5/e/95ef66af-9026-4bb0-a41d-a4f81802d92c/%5bMS-SMTP%5d.pdf
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.
22 * typedef signed short int16;
23 * typedef unsigned short uint16;
24 * typedef unsigned uint32;
25 * typedef unsigned char uint8;
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
30 05-June-2010: PP: handle SASL initial response
37 /* #define DEBUG_SPA */
40 #define DSPA(x,y,z) debug_printf(x,y,z)
45 /* Options specific to the spa authentication mechanism. */
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)) }
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. */
61 int auth_spa_options_count =
62 sizeof(auth_spa_options)/sizeof(optionlist);
64 /* Default private options block for the contidion authentication method. */
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) */
74 /*************************************************
75 * Initialization entry point *
76 *************************************************/
78 /* Called for each instance, after its options have been read, to
79 enable consistency checks to be done, or anything else that needs
83 auth_spa_init(auth_instance *ablock)
85 auth_spa_options_block *ob =
86 (auth_spa_options_block *)(ablock->options_block);
88 /* The public name defaults to the authenticator name */
90 if (ablock->public_name == NULL) ablock->public_name = ablock->name;
92 /* Both username and password must be set for a client */
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;
100 /* For a server we have just one option */
102 ablock->server = ob->spa_serverpassword != NULL;
107 /*************************************************
108 * Server entry point *
109 *************************************************/
111 /* For interface, see auths/README */
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)
119 auth_spa_server(auth_instance *ablock, uschar *data)
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;
131 /* send a 334, MS Exchange style, and grab the client's request,
132 unless we already have it via an initial response. */
134 if ((*data == '\0') &&
135 (auth_get_no64_data(&data, US"NTLM supported") != OK))
137 /* something borked */
141 if (spa_base64_to_bits((char *)(&request), sizeof(request), (const char *)(data)) < 0)
143 DEBUG(D_auth) debug_printf("auth_spa_server(): bad base64 data in "
144 "request: %s\n", data);
148 /* create a challenge and send it back */
150 spa_build_auth_challenge(&request,&challenge);
151 spa_bits_to_base64 (msgbuf, (unsigned char*)&challenge,
152 spa_request_length(&challenge));
154 if (auth_get_no64_data(&data, msgbuf) != OK)
156 /* something borked */
160 /* dump client response */
161 if (spa_base64_to_bits((char *)(&response), sizeof(response), (const char *)(data)) < 0)
163 DEBUG(D_auth) debug_printf("auth_spa_server(): bad base64 data in "
164 "response: %s\n", data);
168 /***************************************************************
169 PH 07-Aug-2003: The original code here was this:
171 Ustrcpy(msgbuf, unicodeToString(((char*)responseptr) +
172 IVAL(&responseptr->uUser.offset,0),
173 SVAL(&responseptr->uUser.len,0)/2) );
175 However, if the response data is too long, unicodeToString bombs out on
176 an assertion failure. It uses a 1024 fixed buffer. Bombing out is not a good
177 idea. It's too messy to try to rework that function to return an error because
178 it is called from a number of other places in the auth-spa.c module. Instead,
179 since it is a very small function, I reproduce its code here, with a size check
180 that causes failure if the size of msgbuf is exceeded. ****/
184 char *p = ((char*)responseptr) + IVAL(&responseptr->uUser.offset,0);
185 int len = SVAL(&responseptr->uUser.len,0)/2;
187 if (len + 1 >= sizeof(msgbuf)) return FAIL;
188 for (i = 0; i < len; ++i)
190 msgbuf[i] = *p & 0x7f;
196 /***************************************************************/
198 /* Put the username in $auth1 and $1. The former is now the preferred variable;
199 the latter is the original variable. */
201 auth_vars[0] = expand_nstring[1] = msgbuf;
202 expand_nlength[1] = Ustrlen(msgbuf);
205 /* clean up globals which aren't referenced, but still shouldn't be left
206 pointing to stack memory */
207 #define CLEANUP_RETURN(Code) do { auth_vars[0] = expand_nstring[1] = NULL; \
208 expand_nlength[1] = expand_nmax = 0; return (Code); } while (0);
210 debug_print_string(ablock->server_debug_string); /* customized debug */
212 /* look up password */
214 clearpass = expand_string(ob->spa_serverpassword);
215 if (clearpass == NULL)
217 if (expand_string_forcedfail)
219 DEBUG(D_auth) debug_printf("auth_spa_server(): forced failure while "
220 "expanding spa_serverpassword\n");
221 CLEANUP_RETURN(FAIL);
225 DEBUG(D_auth) debug_printf("auth_spa_server(): error while expanding "
226 "spa_serverpassword: %s\n", expand_string_message);
227 CLEANUP_RETURN(DEFER);
231 /* create local hash copy */
233 spa_smb_encrypt (clearpass, challenge.challengeData, lmRespData);
234 spa_smb_nt_encrypt (clearpass, challenge.challengeData, ntRespData);
236 /* compare NT hash (LM may not be available) */
238 if (memcmp(ntRespData,
239 ((unsigned char*)responseptr)+IVAL(&responseptr->ntResponse.offset,0),
241 /* success. we have a winner. */
243 int rc = auth_check_serv_cond(ablock);
247 /* Expand server_condition as an authorization check (PH) */
249 CLEANUP_RETURN(FAIL);
253 /*************************************************
254 * Client entry point *
255 *************************************************/
257 /* For interface, see auths/README */
261 auth_instance *ablock, /* authenticator block */
262 smtp_inblock *inblock, /* connection inblock */
263 smtp_outblock *outblock, /* connection outblock */
264 int timeout, /* command timeout */
265 uschar *buffer, /* buffer for reading response */
266 int buffsize) /* size of buffer */
268 auth_spa_options_block *ob =
269 (auth_spa_options_block *)(ablock->options_block);
270 SPAAuthRequest request;
271 SPAAuthChallenge challenge;
272 SPAAuthResponse response;
275 char *username, *password;
277 /* Code added by PH to expand the options */
279 *buffer = 0; /* Default no message when cancelled */
281 username = CS expand_string(ob->spa_username);
282 if (username == NULL)
284 if (expand_string_forcedfail) return CANCELLED;
285 string_format(buffer, buffsize, "expansion of \"%s\" failed in %s "
286 "authenticator: %s", ob->spa_username, ablock->name,
287 expand_string_message);
291 password = CS expand_string(ob->spa_password);
292 if (password == NULL)
294 if (expand_string_forcedfail) return CANCELLED;
295 string_format(buffer, buffsize, "expansion of \"%s\" failed in %s "
296 "authenticator: %s", ob->spa_password, ablock->name,
297 expand_string_message);
301 if (ob->spa_domain != NULL)
303 domain = CS expand_string(ob->spa_domain);
306 if (expand_string_forcedfail) return CANCELLED;
307 string_format(buffer, buffsize, "expansion of \"%s\" failed in %s "
308 "authenticator: %s", ob->spa_domain, ablock->name,
309 expand_string_message);
316 if (smtp_write_command(outblock, FALSE, "AUTH %s\r\n",
317 ablock->public_name) < 0)
320 /* wait for the 3XX OK message */
321 if (!smtp_read_response(inblock, (uschar *)buffer, buffsize, '3', timeout))
324 DSPA("\n\n%s authenticator: using domain %s\n\n",
325 ablock->name, domain);
327 spa_build_auth_request (&request, CS username, domain);
328 spa_bits_to_base64 (US msgbuf, (unsigned char*)&request,
329 spa_request_length(&request));
331 DSPA("\n\n%s authenticator: sending request (%s)\n\n", ablock->name,
334 /* send the encrypted password */
335 if (smtp_write_command(outblock, FALSE, "%s\r\n", msgbuf) < 0)
338 /* wait for the auth challenge */
339 if (!smtp_read_response(inblock, (uschar *)buffer, buffsize, '3', timeout))
342 /* convert the challenge into the challenge struct */
343 DSPA("\n\n%s authenticator: challenge (%s)\n\n",
344 ablock->name, buffer + 4);
345 spa_base64_to_bits ((char *)(&challenge), sizeof(challenge), (const char *)(buffer + 4));
347 spa_build_auth_response (&challenge, &response,
348 CS username, CS password);
349 spa_bits_to_base64 (US msgbuf, (unsigned char*)&response,
350 spa_request_length(&response));
351 DSPA("\n\n%s authenticator: challenge response (%s)\n\n", ablock->name,
354 /* send the challenge response */
355 if (smtp_write_command(outblock, FALSE, "%s\r\n", msgbuf) < 0)
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 if (smtp_read_response(inblock, US buffer, buffsize, '2', timeout))
364 /* Not a success response. If errno != 0 there is some kind of transmission
365 error. Otherwise, check the response code in the buffer. If it starts with
366 '3', more data is expected. */
367 if (errno != 0 || buffer[0] != '3')