1 /* $Cambridge: exim/src/src/auths/spa.c,v 1.11 2010/06/05 10:16:36 pdp Exp $ */
3 /*************************************************
4 * Exim - an Internet mail transport agent *
5 *************************************************/
7 /* Copyright (c) University of Cambridge 1995 - 2009 */
8 /* See the file NOTICE for conditions of use and distribution. */
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.
15 http://www.innovation.ch/java/ntlm.html
16 http://www.kuro5hin.org/story/2002/4/28/1436/66154
17 http://download.microsoft.com/download/9/5/e/95ef66af-9026-4bb0-a41d-a4f81802d92c/%5bMS-SMTP%5d.pdf
19 * It seems that some systems have existing but different definitions of some
20 * of the following types. I received a complaint about "int16" causing
21 * compilation problems. So I (PH) have renamed them all, to be on the safe
22 * side, by adding 'x' on the end. See auths/auth-spa.h.
24 * typedef signed short int16;
25 * typedef unsigned short uint16;
26 * typedef unsigned uint32;
27 * typedef unsigned char uint8;
29 07-August-2003: PH: Patched up the code to avoid assert bombouts for stupid
30 input data. Find appropriate comment by grepping for "PH".
31 16-October-2006: PH: Added a call to auth_check_serv_cond() at the end
32 05-June-2010: PP: handle SASL initial response
39 /* #define DEBUG_SPA */
42 #define DSPA(x,y,z) debug_printf(x,y,z)
47 /* Options specific to the spa authentication mechanism. */
49 optionlist auth_spa_options
[] = {
50 { "client_domain", opt_stringptr
,
51 (void *)(offsetof(auth_spa_options_block
, spa_domain
)) },
52 { "client_password", opt_stringptr
,
53 (void *)(offsetof(auth_spa_options_block
, spa_password
)) },
54 { "client_username", opt_stringptr
,
55 (void *)(offsetof(auth_spa_options_block
, spa_username
)) },
56 { "server_password", opt_stringptr
,
57 (void *)(offsetof(auth_spa_options_block
, spa_serverpassword
)) }
60 /* Size of the options list. An extern variable has to be used so that its
61 address can appear in the tables drtables.c. */
63 int auth_spa_options_count
=
64 sizeof(auth_spa_options
)/sizeof(optionlist
);
66 /* Default private options block for the contidion authentication method. */
68 auth_spa_options_block auth_spa_option_defaults
= {
69 NULL
, /* spa_password */
70 NULL
, /* spa_username */
71 NULL
, /* spa_domain */
72 NULL
/* spa_serverpassword (for server side use) */
76 /*************************************************
77 * Initialization entry point *
78 *************************************************/
80 /* Called for each instance, after its options have been read, to
81 enable consistency checks to be done, or anything else that needs
85 auth_spa_init(auth_instance
*ablock
)
87 auth_spa_options_block
*ob
=
88 (auth_spa_options_block
*)(ablock
->options_block
);
90 /* The public name defaults to the authenticator name */
92 if (ablock
->public_name
== NULL
) ablock
->public_name
= ablock
->name
;
94 /* Both username and password must be set for a client */
96 if ((ob
->spa_username
== NULL
) != (ob
->spa_password
== NULL
))
97 log_write(0, LOG_PANIC_DIE
|LOG_CONFIG_FOR
, "%s authenticator:\n "
98 "one of client_username and client_password cannot be set without "
99 "the other", ablock
->name
);
100 ablock
->client
= ob
->spa_username
!= NULL
;
102 /* For a server we have just one option */
104 ablock
->server
= ob
->spa_serverpassword
!= NULL
;
109 /*************************************************
110 * Server entry point *
111 *************************************************/
113 /* For interface, see auths/README */
115 #define CVAL(buf,pos) (((unsigned char *)(buf))[pos])
116 #define PVAL(buf,pos) ((unsigned)CVAL(buf,pos))
117 #define SVAL(buf,pos) (PVAL(buf,pos)|PVAL(buf,(pos)+1)<<8)
118 #define IVAL(buf,pos) (SVAL(buf,pos)|SVAL(buf,(pos)+2)<<16)
121 auth_spa_server(auth_instance
*ablock
, uschar
*data
)
123 auth_spa_options_block
*ob
= (auth_spa_options_block
*)(ablock
->options_block
);
124 uint8x lmRespData
[24];
125 uint8x ntRespData
[24];
126 SPAAuthRequest request
;
127 SPAAuthChallenge challenge
;
128 SPAAuthResponse response
;
129 SPAAuthResponse
*responseptr
= &response
;
133 /* send a 334, MS Exchange style, and grab the client's request,
134 unless we already have it via an initial response. */
136 if ((*data
== '\0') &&
137 (auth_get_no64_data(&data
, US
"NTLM supported") != OK
))
139 /* something borked */
143 if (spa_base64_to_bits((char *)(&request
), sizeof(request
), (const char *)(data
)) < 0)
145 DEBUG(D_auth
) debug_printf("auth_spa_server(): bad base64 data in "
146 "request: %s\n", data
);
150 /* create a challenge and send it back */
152 spa_build_auth_challenge(&request
,&challenge
);
153 spa_bits_to_base64 (msgbuf
, (unsigned char*)&challenge
,
154 spa_request_length(&challenge
));
156 if (auth_get_no64_data(&data
, msgbuf
) != OK
)
158 /* something borked */
162 /* dump client response */
163 if (spa_base64_to_bits((char *)(&response
), sizeof(response
), (const char *)(data
)) < 0)
165 DEBUG(D_auth
) debug_printf("auth_spa_server(): bad base64 data in "
166 "response: %s\n", data
);
170 /***************************************************************
171 PH 07-Aug-2003: The original code here was this:
173 Ustrcpy(msgbuf, unicodeToString(((char*)responseptr) +
174 IVAL(&responseptr->uUser.offset,0),
175 SVAL(&responseptr->uUser.len,0)/2) );
177 However, if the response data is too long, unicodeToString bombs out on
178 an assertion failure. It uses a 1024 fixed buffer. Bombing out is not a good
179 idea. It's too messy to try to rework that function to return an error because
180 it is called from a number of other places in the auth-spa.c module. Instead,
181 since it is a very small function, I reproduce its code here, with a size check
182 that causes failure if the size of msgbuf is exceeded. ****/
186 char *p
= ((char*)responseptr
) + IVAL(&responseptr
->uUser
.offset
,0);
187 int len
= SVAL(&responseptr
->uUser
.len
,0)/2;
189 if (len
+ 1 >= sizeof(msgbuf
)) return FAIL
;
190 for (i
= 0; i
< len
; ++i
)
192 msgbuf
[i
] = *p
& 0x7f;
198 /***************************************************************/
200 /* Put the username in $auth1 and $1. The former is now the preferred variable;
201 the latter is the original variable. */
203 auth_vars
[0] = expand_nstring
[1] = msgbuf
;
204 expand_nlength
[1] = Ustrlen(msgbuf
);
207 debug_print_string(ablock
->server_debug_string
); /* customized debug */
209 /* look up password */
211 clearpass
= expand_string(ob
->spa_serverpassword
);
212 if (clearpass
== NULL
)
214 if (expand_string_forcedfail
)
216 DEBUG(D_auth
) debug_printf("auth_spa_server(): forced failure while "
217 "expanding spa_serverpassword\n");
222 DEBUG(D_auth
) debug_printf("auth_spa_server(): error while expanding "
223 "spa_serverpassword: %s\n", expand_string_message
);
228 /* create local hash copy */
230 spa_smb_encrypt (clearpass
, challenge
.challengeData
, lmRespData
);
231 spa_smb_nt_encrypt (clearpass
, challenge
.challengeData
, ntRespData
);
233 /* compare NT hash (LM may not be available) */
235 if (memcmp(ntRespData
,
236 ((unsigned char*)responseptr
)+IVAL(&responseptr
->ntResponse
.offset
,0),
238 /* success. we have a winner. */
240 /* Expand server_condition as an authorization check (PH) */
241 return auth_check_serv_cond(ablock
);
247 /*************************************************
248 * Client entry point *
249 *************************************************/
251 /* For interface, see auths/README */
255 auth_instance
*ablock
, /* authenticator block */
256 smtp_inblock
*inblock
, /* connection inblock */
257 smtp_outblock
*outblock
, /* connection outblock */
258 int timeout
, /* command timeout */
259 uschar
*buffer
, /* buffer for reading response */
260 int buffsize
) /* size of buffer */
262 auth_spa_options_block
*ob
=
263 (auth_spa_options_block
*)(ablock
->options_block
);
264 SPAAuthRequest request
;
265 SPAAuthChallenge challenge
;
266 SPAAuthResponse response
;
269 char *username
, *password
;
271 /* Code added by PH to expand the options */
273 *buffer
= 0; /* Default no message when cancelled */
275 username
= CS
expand_string(ob
->spa_username
);
276 if (username
== NULL
)
278 if (expand_string_forcedfail
) return CANCELLED
;
279 string_format(buffer
, buffsize
, "expansion of \"%s\" failed in %s "
280 "authenticator: %s", ob
->spa_username
, ablock
->name
,
281 expand_string_message
);
285 password
= CS
expand_string(ob
->spa_password
);
286 if (password
== NULL
)
288 if (expand_string_forcedfail
) return CANCELLED
;
289 string_format(buffer
, buffsize
, "expansion of \"%s\" failed in %s "
290 "authenticator: %s", ob
->spa_password
, ablock
->name
,
291 expand_string_message
);
295 if (ob
->spa_domain
!= NULL
)
297 domain
= CS
expand_string(ob
->spa_domain
);
300 if (expand_string_forcedfail
) return CANCELLED
;
301 string_format(buffer
, buffsize
, "expansion of \"%s\" failed in %s "
302 "authenticator: %s", ob
->spa_domain
, ablock
->name
,
303 expand_string_message
);
310 if (smtp_write_command(outblock
, FALSE
, "AUTH %s\r\n",
311 ablock
->public_name
) < 0)
314 /* wait for the 3XX OK message */
315 if (!smtp_read_response(inblock
, (uschar
*)buffer
, buffsize
, '3', timeout
))
318 DSPA("\n\n%s authenticator: using domain %s\n\n",
319 ablock
->name
, domain
);
321 spa_build_auth_request (&request
, CS username
, domain
);
322 spa_bits_to_base64 (US msgbuf
, (unsigned char*)&request
,
323 spa_request_length(&request
));
325 DSPA("\n\n%s authenticator: sending request (%s)\n\n", ablock
->name
,
328 /* send the encrypted password */
329 if (smtp_write_command(outblock
, FALSE
, "%s\r\n", msgbuf
) < 0)
332 /* wait for the auth challenge */
333 if (!smtp_read_response(inblock
, (uschar
*)buffer
, buffsize
, '3', timeout
))
336 /* convert the challenge into the challenge struct */
337 DSPA("\n\n%s authenticator: challenge (%s)\n\n",
338 ablock
->name
, buffer
+ 4);
339 spa_base64_to_bits ((char *)(&challenge
), sizeof(challenge
), (const char *)(buffer
+ 4));
341 spa_build_auth_response (&challenge
, &response
,
342 CS username
, CS password
);
343 spa_bits_to_base64 (US msgbuf
, (unsigned char*)&response
,
344 spa_request_length(&response
));
345 DSPA("\n\n%s authenticator: challenge response (%s)\n\n", ablock
->name
,
348 /* send the challenge response */
349 if (smtp_write_command(outblock
, FALSE
, "%s\r\n", msgbuf
) < 0)
352 /* If we receive a success response from the server, authentication
353 has succeeded. There may be more data to send, but is there any point
354 in provoking an error here? */
355 if (smtp_read_response(inblock
, US buffer
, buffsize
, '2', timeout
))
358 /* Not a success response. If errno != 0 there is some kind of transmission
359 error. Otherwise, check the response code in the buffer. If it starts with
360 '3', more data is expected. */
361 if (errno
!= 0 || buffer
[0] != '3')