1 /* $Cambridge: exim/src/src/auths/spa.c,v 1.9 2007/01/08 10:50:19 ph10 Exp $ */
3 /*************************************************
4 * Exim - an Internet mail transport agent *
5 *************************************************/
7 /* Copyright (c) University of Cambridge 1995 - 2007 */
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
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.
23 * typedef signed short int16;
24 * typedef unsigned short uint16;
25 * typedef unsigned uint32;
26 * typedef unsigned char uint8;
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
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 */
133 if (auth_get_no64_data(&data
, US
"NTLM supported") != OK
)
135 /* something borked */
139 if (spa_base64_to_bits((char *)(&request
), sizeof(request
), (const char *)(data
)) < 0)
141 DEBUG(D_auth
) debug_printf("auth_spa_server(): bad base64 data in "
142 "request: %s\n", data
);
146 /* create a challenge and send it back */
148 spa_build_auth_challenge(&request
,&challenge
);
149 spa_bits_to_base64 (msgbuf
, (unsigned char*)&challenge
,
150 spa_request_length(&challenge
));
152 if (auth_get_no64_data(&data
, msgbuf
) != OK
)
154 /* something borked */
158 /* dump client response */
159 if (spa_base64_to_bits((char *)(&response
), sizeof(response
), (const char *)(data
)) < 0)
161 DEBUG(D_auth
) debug_printf("auth_spa_server(): bad base64 data in "
162 "response: %s\n", data
);
166 /***************************************************************
167 PH 07-Aug-2003: The original code here was this:
169 Ustrcpy(msgbuf, unicodeToString(((char*)responseptr) +
170 IVAL(&responseptr->uUser.offset,0),
171 SVAL(&responseptr->uUser.len,0)/2) );
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. ****/
182 char *p
= ((char*)responseptr
) + IVAL(&responseptr
->uUser
.offset
,0);
183 int len
= SVAL(&responseptr
->uUser
.len
,0)/2;
185 if (len
+ 1 >= sizeof(msgbuf
)) return FAIL
;
186 for (i
= 0; i
< len
; ++i
)
188 msgbuf
[i
] = *p
& 0x7f;
194 /***************************************************************/
196 /* Put the username in $auth1 and $1. The former is now the preferred variable;
197 the latter is the original variable. */
199 auth_vars
[0] = expand_nstring
[1] = msgbuf
;
200 expand_nlength
[1] = Ustrlen(msgbuf
);
203 debug_print_string(ablock
->server_debug_string
); /* customized debug */
205 /* look up password */
207 clearpass
= expand_string(ob
->spa_serverpassword
);
208 if (clearpass
== NULL
)
210 if (expand_string_forcedfail
)
212 DEBUG(D_auth
) debug_printf("auth_spa_server(): forced failure while "
213 "expanding spa_serverpassword\n");
218 DEBUG(D_auth
) debug_printf("auth_spa_server(): error while expanding "
219 "spa_serverpassword: %s\n", expand_string_message
);
224 /* create local hash copy */
226 spa_smb_encrypt (clearpass
, challenge
.challengeData
, lmRespData
);
227 spa_smb_nt_encrypt (clearpass
, challenge
.challengeData
, ntRespData
);
229 /* compare NT hash (LM may not be available) */
231 if (memcmp(ntRespData
,
232 ((unsigned char*)responseptr
)+IVAL(&responseptr
->ntResponse
.offset
,0),
234 /* success. we have a winner. */
236 /* Expand server_condition as an authorization check (PH) */
237 return auth_check_serv_cond(ablock
);
243 /*************************************************
244 * Client entry point *
245 *************************************************/
247 /* For interface, see auths/README */
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 */
258 auth_spa_options_block
*ob
=
259 (auth_spa_options_block
*)(ablock
->options_block
);
260 SPAAuthRequest request
;
261 SPAAuthChallenge challenge
;
262 SPAAuthResponse response
;
265 char *username
, *password
;
267 /* Code added by PH to expand the options */
269 *buffer
= 0; /* Default no message when cancelled */
271 username
= CS
expand_string(ob
->spa_username
);
272 if (username
== NULL
)
274 if (expand_string_forcedfail
) return CANCELLED
;
275 string_format(buffer
, buffsize
, "expansion of \"%s\" failed in %s "
276 "authenticator: %s", ob
->spa_username
, ablock
->name
,
277 expand_string_message
);
281 password
= CS
expand_string(ob
->spa_password
);
282 if (password
== NULL
)
284 if (expand_string_forcedfail
) return CANCELLED
;
285 string_format(buffer
, buffsize
, "expansion of \"%s\" failed in %s "
286 "authenticator: %s", ob
->spa_password
, ablock
->name
,
287 expand_string_message
);
291 if (ob
->spa_domain
!= NULL
)
293 domain
= CS
expand_string(ob
->spa_domain
);
296 if (expand_string_forcedfail
) return CANCELLED
;
297 string_format(buffer
, buffsize
, "expansion of \"%s\" failed in %s "
298 "authenticator: %s", ob
->spa_domain
, ablock
->name
,
299 expand_string_message
);
306 if (smtp_write_command(outblock
, FALSE
, "AUTH %s\r\n",
307 ablock
->public_name
) < 0)
310 /* wait for the 3XX OK message */
311 if (!smtp_read_response(inblock
, (uschar
*)buffer
, buffsize
, '3', timeout
))
314 DSPA("\n\n%s authenticator: using domain %s\n\n",
315 ablock
->name
, domain
);
317 spa_build_auth_request (&request
, CS username
, domain
);
318 spa_bits_to_base64 (US msgbuf
, (unsigned char*)&request
,
319 spa_request_length(&request
));
321 DSPA("\n\n%s authenticator: sending request (%s)\n\n", ablock
->name
,
324 /* send the encrypted password */
325 if (smtp_write_command(outblock
, FALSE
, "%s\r\n", msgbuf
) < 0)
328 /* wait for the auth challenge */
329 if (!smtp_read_response(inblock
, (uschar
*)buffer
, buffsize
, '3', timeout
))
332 /* convert the challenge into the challenge struct */
333 DSPA("\n\n%s authenticator: challenge (%s)\n\n",
334 ablock
->name
, buffer
+ 4);
335 spa_base64_to_bits ((char *)(&challenge
), sizeof(challenge
), (const char *)(buffer
+ 4));
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
,
344 /* send the challenge response */
345 if (smtp_write_command(outblock
, FALSE
, "%s\r\n", msgbuf
) < 0)
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
))
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')