1 /* $Cambridge: exim/src/src/auths/spa.c,v 1.7 2006/02/23 12:41:22 ph10 Exp $ */
3 /*************************************************
4 * Exim - an Internet mail transport agent *
5 *************************************************/
7 /* Copyright (c) University of Cambridge 1995 - 2006 */
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".
36 /* #define DEBUG_SPA */
39 #define DSPA(x,y,z) debug_printf(x,y,z)
44 /* Options specific to the spa authentication mechanism. */
46 optionlist auth_spa_options
[] = {
47 { "client_domain", opt_stringptr
,
48 (void *)(offsetof(auth_spa_options_block
, spa_domain
)) },
49 { "client_password", opt_stringptr
,
50 (void *)(offsetof(auth_spa_options_block
, spa_password
)) },
51 { "client_username", opt_stringptr
,
52 (void *)(offsetof(auth_spa_options_block
, spa_username
)) },
53 { "server_password", opt_stringptr
,
54 (void *)(offsetof(auth_spa_options_block
, spa_serverpassword
)) }
57 /* Size of the options list. An extern variable has to be used so that its
58 address can appear in the tables drtables.c. */
60 int auth_spa_options_count
=
61 sizeof(auth_spa_options
)/sizeof(optionlist
);
63 /* Default private options block for the contidion authentication method. */
65 auth_spa_options_block auth_spa_option_defaults
= {
66 NULL
, /* spa_password */
67 NULL
, /* spa_username */
68 NULL
, /* spa_domain */
69 NULL
/* spa_serverpassword (for server side use) */
73 /*************************************************
74 * Initialization entry point *
75 *************************************************/
77 /* Called for each instance, after its options have been read, to
78 enable consistency checks to be done, or anything else that needs
82 auth_spa_init(auth_instance
*ablock
)
84 auth_spa_options_block
*ob
=
85 (auth_spa_options_block
*)(ablock
->options_block
);
87 /* The public name defaults to the authenticator name */
89 if (ablock
->public_name
== NULL
) ablock
->public_name
= ablock
->name
;
91 /* Both username and password must be set for a client */
93 if ((ob
->spa_username
== NULL
) != (ob
->spa_password
== NULL
))
94 log_write(0, LOG_PANIC_DIE
|LOG_CONFIG_FOR
, "%s authenticator:\n "
95 "one of client_username and client_password cannot be set without "
96 "the other", ablock
->name
);
97 ablock
->client
= ob
->spa_username
!= NULL
;
99 /* For a server we have just one option */
101 ablock
->server
= ob
->spa_serverpassword
!= NULL
;
106 /*************************************************
107 * Server entry point *
108 *************************************************/
110 /* For interface, see auths/README */
112 #define CVAL(buf,pos) (((unsigned char *)(buf))[pos])
113 #define PVAL(buf,pos) ((unsigned)CVAL(buf,pos))
114 #define SVAL(buf,pos) (PVAL(buf,pos)|PVAL(buf,(pos)+1)<<8)
115 #define IVAL(buf,pos) (SVAL(buf,pos)|SVAL(buf,(pos)+2)<<16)
118 auth_spa_server(auth_instance
*ablock
, uschar
*data
)
120 auth_spa_options_block
*ob
= (auth_spa_options_block
*)(ablock
->options_block
);
121 uint8x lmRespData
[24];
122 uint8x ntRespData
[24];
123 SPAAuthRequest request
;
124 SPAAuthChallenge challenge
;
125 SPAAuthResponse response
;
126 SPAAuthResponse
*responseptr
= &response
;
130 /* send a 334, MS Exchange style, and grab the client's request */
132 if (auth_get_no64_data(&data
, US
"NTLM supported") != OK
)
134 /* something borked */
138 if (spa_base64_to_bits((char *)(&request
), sizeof(request
), (const char *)(data
)) < 0)
140 DEBUG(D_auth
) debug_printf("auth_spa_server(): bad base64 data in "
141 "request: %s\n", data
);
145 /* create a challenge and send it back */
147 spa_build_auth_challenge(&request
,&challenge
);
148 spa_bits_to_base64 (msgbuf
, (unsigned char*)&challenge
,
149 spa_request_length(&challenge
));
151 if (auth_get_no64_data(&data
, msgbuf
) != OK
)
153 /* something borked */
157 /* dump client response */
158 if (spa_base64_to_bits((char *)(&response
), sizeof(response
), (const char *)(data
)) < 0)
160 DEBUG(D_auth
) debug_printf("auth_spa_server(): bad base64 data in "
161 "response: %s\n", data
);
165 /***************************************************************
166 PH 07-Aug-2003: The original code here was this:
168 Ustrcpy(msgbuf, unicodeToString(((char*)responseptr) +
169 IVAL(&responseptr->uUser.offset,0),
170 SVAL(&responseptr->uUser.len,0)/2) );
172 However, if the response data is too long, unicodeToString bombs out on
173 an assertion failure. It uses a 1024 fixed buffer. Bombing out is not a good
174 idea. It's too messy to try to rework that function to return an error because
175 it is called from a number of other places in the auth-spa.c module. Instead,
176 since it is a very small function, I reproduce its code here, with a size check
177 that causes failure if the size of msgbuf is exceeded. ****/
181 char *p
= ((char*)responseptr
) + IVAL(&responseptr
->uUser
.offset
,0);
182 int len
= SVAL(&responseptr
->uUser
.len
,0)/2;
184 if (len
+ 1 >= sizeof(msgbuf
)) return FAIL
;
185 for (i
= 0; i
< len
; ++i
)
187 msgbuf
[i
] = *p
& 0x7f;
193 /***************************************************************/
195 /* Put the username in $auth1 and $1. The former is now the preferred variable;
196 the latter is the original variable. */
198 auth_vars
[0] = expand_nstring
[1] = msgbuf
;
199 expand_nlength
[1] = Ustrlen(msgbuf
);
202 debug_print_string(ablock
->server_debug_string
); /* customized debug */
204 /* look up password */
206 clearpass
= expand_string(ob
->spa_serverpassword
);
207 if (clearpass
== NULL
)
209 if (expand_string_forcedfail
)
211 DEBUG(D_auth
) debug_printf("auth_spa_server(): forced failure while "
212 "expanding spa_serverpassword\n");
217 DEBUG(D_auth
) debug_printf("auth_spa_server(): error while expanding "
218 "spa_serverpassword: %s\n", expand_string_message
);
223 /* create local hash copy */
225 spa_smb_encrypt (clearpass
, challenge
.challengeData
, lmRespData
);
226 spa_smb_nt_encrypt (clearpass
, challenge
.challengeData
, ntRespData
);
228 /* compare NT hash (LM may not be available) */
230 if (memcmp(ntRespData
,
231 ((unsigned char*)responseptr
)+IVAL(&responseptr
->ntResponse
.offset
,0),
233 /* success. we have a winner. */
240 /*************************************************
241 * Client entry point *
242 *************************************************/
244 /* For interface, see auths/README */
248 auth_instance
*ablock
, /* authenticator block */
249 smtp_inblock
*inblock
, /* connection inblock */
250 smtp_outblock
*outblock
, /* connection outblock */
251 int timeout
, /* command timeout */
252 uschar
*buffer
, /* buffer for reading response */
253 int buffsize
) /* size of buffer */
255 auth_spa_options_block
*ob
=
256 (auth_spa_options_block
*)(ablock
->options_block
);
257 SPAAuthRequest request
;
258 SPAAuthChallenge challenge
;
259 SPAAuthResponse response
;
262 char *username
, *password
;
264 /* Code added by PH to expand the options */
266 *buffer
= 0; /* Default no message when cancelled */
268 username
= CS
expand_string(ob
->spa_username
);
269 if (username
== NULL
)
271 if (expand_string_forcedfail
) return CANCELLED
;
272 string_format(buffer
, buffsize
, "expansion of \"%s\" failed in %s "
273 "authenticator: %s", ob
->spa_username
, ablock
->name
,
274 expand_string_message
);
278 password
= CS
expand_string(ob
->spa_password
);
279 if (password
== NULL
)
281 if (expand_string_forcedfail
) return CANCELLED
;
282 string_format(buffer
, buffsize
, "expansion of \"%s\" failed in %s "
283 "authenticator: %s", ob
->spa_password
, ablock
->name
,
284 expand_string_message
);
288 if (ob
->spa_domain
!= NULL
)
290 domain
= CS
expand_string(ob
->spa_domain
);
293 if (expand_string_forcedfail
) return CANCELLED
;
294 string_format(buffer
, buffsize
, "expansion of \"%s\" failed in %s "
295 "authenticator: %s", ob
->spa_domain
, ablock
->name
,
296 expand_string_message
);
303 if (smtp_write_command(outblock
, FALSE
, "AUTH %s\r\n",
304 ablock
->public_name
) < 0)
307 /* wait for the 3XX OK message */
308 if (!smtp_read_response(inblock
, (uschar
*)buffer
, buffsize
, '3', timeout
))
311 DSPA("\n\n%s authenticator: using domain %s\n\n",
312 ablock
->name
, domain
);
314 spa_build_auth_request (&request
, CS username
, domain
);
315 spa_bits_to_base64 (US msgbuf
, (unsigned char*)&request
,
316 spa_request_length(&request
));
318 DSPA("\n\n%s authenticator: sending request (%s)\n\n", ablock
->name
,
321 /* send the encrypted password */
322 if (smtp_write_command(outblock
, FALSE
, "%s\r\n", msgbuf
) < 0)
325 /* wait for the auth challenge */
326 if (!smtp_read_response(inblock
, (uschar
*)buffer
, buffsize
, '3', timeout
))
329 /* convert the challenge into the challenge struct */
330 DSPA("\n\n%s authenticator: challenge (%s)\n\n",
331 ablock
->name
, buffer
+ 4);
332 spa_base64_to_bits ((char *)(&challenge
), sizeof(challenge
), (const char *)(buffer
+ 4));
334 spa_build_auth_response (&challenge
, &response
,
335 CS username
, CS password
);
336 spa_bits_to_base64 (US msgbuf
, (unsigned char*)&response
,
337 spa_request_length(&response
));
338 DSPA("\n\n%s authenticator: challenge response (%s)\n\n", ablock
->name
,
341 /* send the challenge response */
342 if (smtp_write_command(outblock
, FALSE
, "%s\r\n", msgbuf
) < 0)
345 /* If we receive a success response from the server, authentication
346 has succeeded. There may be more data to send, but is there any point
347 in provoking an error here? */
348 if (smtp_read_response(inblock
, US buffer
, buffsize
, '2', timeout
))
351 /* Not a success response. If errno != 0 there is some kind of transmission
352 error. Otherwise, check the response code in the buffer. If it starts with
353 '3', more data is expected. */
354 if (errno
!= 0 || buffer
[0] != '3')