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')