[exim.git] / src / src / auths / spa.c

/* $Cambridge: exim/src/src/auths/spa.c,v 1.11 2010/06/05 10:16:36 pdp Exp $ */

/*************************************************
*     Exim - an Internet mail transport agent    *
*************************************************/

/* Copyright (c) University of Cambridge 1995 - 2009 */
/* See the file NOTICE for conditions of use and distribution. */

/* This file, which provides support for Microsoft's Secure Password
Authentication, was contributed by Marc Prud'hommeaux. Tom Kistner added SPA
server support. I (PH) have only modified it in very trivial ways.

References:
  http://www.innovation.ch/java/ntlm.html
  http://www.kuro5hin.org/story/2002/4/28/1436/66154
  http://download.microsoft.com/download/9/5/e/95ef66af-9026-4bb0-a41d-a4f81802d92c/%5bMS-SMTP%5d.pdf

 * It seems that some systems have existing but different definitions of some
 * of the following types. I received a complaint about "int16" causing
 * compilation problems. So I (PH) have renamed them all, to be on the safe
 * side, by adding 'x' on the end. See auths/auth-spa.h.

 * typedef signed short int16;
 * typedef unsigned short uint16;
 * typedef unsigned uint32;
 * typedef unsigned char  uint8;

07-August-2003:  PH: Patched up the code to avoid assert bombouts for stupid
                     input data. Find appropriate comment by grepping for "PH".
16-October-2006: PH: Added a call to auth_check_serv_cond() at the end
05-June-2010:    PP: handle SASL initial response
*/


#include "../exim.h"
#include "spa.h"

/* #define DEBUG_SPA */

#ifdef DEBUG_SPA
#define DSPA(x,y,z)   debug_printf(x,y,z)
#else
#define DSPA(x,y,z)
#endif

/* Options specific to the spa authentication mechanism. */

optionlist auth_spa_options[] = {
  { "client_domain",             opt_stringptr,
      (void *)(offsetof(auth_spa_options_block, spa_domain)) },
  { "client_password",           opt_stringptr,
      (void *)(offsetof(auth_spa_options_block, spa_password)) },
  { "client_username",           opt_stringptr,
      (void *)(offsetof(auth_spa_options_block, spa_username)) },
  { "server_password",           opt_stringptr,
      (void *)(offsetof(auth_spa_options_block, spa_serverpassword)) }
};

/* Size of the options list. An extern variable has to be used so that its
address can appear in the tables drtables.c. */

int auth_spa_options_count =
  sizeof(auth_spa_options)/sizeof(optionlist);

/* Default private options block for the contidion authentication method. */

auth_spa_options_block auth_spa_option_defaults = {
  NULL,              /* spa_password */
  NULL,              /* spa_username */
  NULL,              /* spa_domain */
  NULL               /* spa_serverpassword (for server side use) */
};


/*************************************************
*          Initialization entry point            *
*************************************************/

/* Called for each instance, after its options have been read, to
enable consistency checks to be done, or anything else that needs
to be set up. */

void
auth_spa_init(auth_instance *ablock)
{
auth_spa_options_block *ob =
  (auth_spa_options_block *)(ablock->options_block);

/* The public name defaults to the authenticator name */

if (ablock->public_name == NULL) ablock->public_name = ablock->name;

/* Both username and password must be set for a client */

if ((ob->spa_username == NULL) != (ob->spa_password == NULL))
  log_write(0, LOG_PANIC_DIE|LOG_CONFIG_FOR, "%s authenticator:\n  "
      "one of client_username and client_password cannot be set without "
      "the other", ablock->name);
ablock->client = ob->spa_username != NULL;

/* For a server we have just one option */

ablock->server = ob->spa_serverpassword != NULL;
}


/*************************************************
*             Server entry point                 *
*************************************************/

/* For interface, see auths/README */

#define CVAL(buf,pos) (((unsigned char *)(buf))[pos])
#define PVAL(buf,pos) ((unsigned)CVAL(buf,pos))
#define SVAL(buf,pos) (PVAL(buf,pos)|PVAL(buf,(pos)+1)<<8)
#define IVAL(buf,pos) (SVAL(buf,pos)|SVAL(buf,(pos)+2)<<16)

int
auth_spa_server(auth_instance *ablock, uschar *data)
{
auth_spa_options_block *ob = (auth_spa_options_block *)(ablock->options_block);
uint8x lmRespData[24];
uint8x ntRespData[24];
SPAAuthRequest request;
SPAAuthChallenge challenge;
SPAAuthResponse  response;
SPAAuthResponse  *responseptr = &response;
uschar msgbuf[2048];
uschar *clearpass;

/* send a 334, MS Exchange style, and grab the client's request,
unless we already have it via an initial response. */

if ((*data == '\0') &&
    (auth_get_no64_data(&data, US"NTLM supported") != OK))
  {
  /* something borked */
  return FAIL;
  }

if (spa_base64_to_bits((char *)(&request), sizeof(request), (const char *)(data)) < 0)
  {
  DEBUG(D_auth) debug_printf("auth_spa_server(): bad base64 data in "
  "request: %s\n", data);
  return FAIL;
  }

/* create a challenge and send it back */

spa_build_auth_challenge(&request,&challenge);
spa_bits_to_base64 (msgbuf, (unsigned char*)&challenge,
    spa_request_length(&challenge));

if (auth_get_no64_data(&data, msgbuf) != OK)
  {
  /* something borked */
  return FAIL;
  }

/* dump client response */
if (spa_base64_to_bits((char *)(&response), sizeof(response), (const char *)(data)) < 0)
  {
  DEBUG(D_auth) debug_printf("auth_spa_server(): bad base64 data in "
  "response: %s\n", data);
  return FAIL;
  }

/***************************************************************
PH 07-Aug-2003: The original code here was this:

Ustrcpy(msgbuf, unicodeToString(((char*)responseptr) +
  IVAL(&responseptr->uUser.offset,0),
  SVAL(&responseptr->uUser.len,0)/2) );

However, if the response data is too long, unicodeToString bombs out on
an assertion failure. It uses a 1024 fixed buffer. Bombing out is not a good
idea. It's too messy to try to rework that function to return an error because
it is called from a number of other places in the auth-spa.c module. Instead,
since it is a very small function, I reproduce its code here, with a size check
that causes failure if the size of msgbuf is exceeded. ****/

  {
  int i;
  char *p = ((char*)responseptr) + IVAL(&responseptr->uUser.offset,0);
  int len = SVAL(&responseptr->uUser.len,0)/2;

  if (len + 1 >= sizeof(msgbuf)) return FAIL;
  for (i = 0; i < len; ++i)
    {
    msgbuf[i] = *p & 0x7f;
    p += 2;
    }
  msgbuf[i] = 0;
  }

/***************************************************************/

/* Put the username in $auth1 and $1. The former is now the preferred variable;
the latter is the original variable. */

auth_vars[0] = expand_nstring[1] = msgbuf;
expand_nlength[1] = Ustrlen(msgbuf);
expand_nmax = 1;

debug_print_string(ablock->server_debug_string);    /* customized debug */

/* look up password */

clearpass = expand_string(ob->spa_serverpassword);
if (clearpass == NULL)
  {
  if (expand_string_forcedfail)
    {
    DEBUG(D_auth) debug_printf("auth_spa_server(): forced failure while "
      "expanding spa_serverpassword\n");
    return FAIL;
    }
  else
    {
    DEBUG(D_auth) debug_printf("auth_spa_server(): error while expanding "
      "spa_serverpassword: %s\n", expand_string_message);
    return DEFER;
    }
  }

/* create local hash copy */

spa_smb_encrypt (clearpass, challenge.challengeData, lmRespData);
spa_smb_nt_encrypt (clearpass, challenge.challengeData, ntRespData);

/* compare NT hash (LM may not be available) */

if (memcmp(ntRespData,
      ((unsigned char*)responseptr)+IVAL(&responseptr->ntResponse.offset,0),
      24) == 0)
  /* success. we have a winner. */

  /* Expand server_condition as an authorization check (PH) */
  return auth_check_serv_cond(ablock);

return FAIL;
}


/*************************************************
*              Client entry point                *
*************************************************/

/* For interface, see auths/README */

int
auth_spa_client(
  auth_instance *ablock,                 /* authenticator block */
  smtp_inblock *inblock,                 /* connection inblock */
  smtp_outblock *outblock,               /* connection outblock */
  int timeout,                           /* command timeout */
  uschar *buffer,                        /* buffer for reading response */
  int buffsize)                          /* size of buffer */
{
       auth_spa_options_block *ob =
               (auth_spa_options_block *)(ablock->options_block);
       SPAAuthRequest   request;
       SPAAuthChallenge challenge;
       SPAAuthResponse  response;
       char msgbuf[2048];
       char *domain = NULL;
       char *username, *password;

       /* Code added by PH to expand the options */

       *buffer = 0;    /* Default no message when cancelled */

       username = CS expand_string(ob->spa_username);
       if (username == NULL)
         {
         if (expand_string_forcedfail) return CANCELLED;
         string_format(buffer, buffsize, "expansion of \"%s\" failed in %s "
           "authenticator: %s", ob->spa_username, ablock->name,
           expand_string_message);
         return ERROR;
         }

       password = CS expand_string(ob->spa_password);
       if (password == NULL)
         {
         if (expand_string_forcedfail) return CANCELLED;
         string_format(buffer, buffsize, "expansion of \"%s\" failed in %s "
           "authenticator: %s", ob->spa_password, ablock->name,
           expand_string_message);
         return ERROR;
         }

       if (ob->spa_domain != NULL)
         {
         domain = CS expand_string(ob->spa_domain);
         if (domain == NULL)
           {
           if (expand_string_forcedfail) return CANCELLED;
           string_format(buffer, buffsize, "expansion of \"%s\" failed in %s "
             "authenticator: %s", ob->spa_domain, ablock->name,
             expand_string_message);
           return ERROR;
           }
         }

       /* Original code */

    if (smtp_write_command(outblock, FALSE, "AUTH %s\r\n",
         ablock->public_name) < 0)
               return FAIL_SEND;

       /* wait for the 3XX OK message */
       if (!smtp_read_response(inblock, (uschar *)buffer, buffsize, '3', timeout))
               return FAIL;

       DSPA("\n\n%s authenticator: using domain %s\n\n",
               ablock->name, domain);

       spa_build_auth_request (&request, CS username, domain);
       spa_bits_to_base64 (US msgbuf, (unsigned char*)&request,
               spa_request_length(&request));

       DSPA("\n\n%s authenticator: sending request (%s)\n\n", ablock->name,
               msgbuf);

       /* send the encrypted password */
       if (smtp_write_command(outblock, FALSE, "%s\r\n", msgbuf) < 0)
               return FAIL_SEND;

       /* wait for the auth challenge */
       if (!smtp_read_response(inblock, (uschar *)buffer, buffsize, '3', timeout))
               return FAIL;

       /* convert the challenge into the challenge struct */
       DSPA("\n\n%s authenticator: challenge (%s)\n\n",
               ablock->name, buffer + 4);
       spa_base64_to_bits ((char *)(&challenge), sizeof(challenge), (const char *)(buffer + 4));

       spa_build_auth_response (&challenge, &response,
               CS username, CS password);
       spa_bits_to_base64 (US msgbuf, (unsigned char*)&response,
               spa_request_length(&response));
       DSPA("\n\n%s authenticator: challenge response (%s)\n\n", ablock->name,
               msgbuf);

       /* send the challenge response */
       if (smtp_write_command(outblock, FALSE, "%s\r\n", msgbuf) < 0)
               return FAIL_SEND;

       /* If we receive a success response from the server, authentication
       has succeeded. There may be more data to send, but is there any point
       in provoking an error here? */
       if (smtp_read_response(inblock, US buffer, buffsize, '2', timeout))
               return OK;

       /* Not a success response. If errno != 0 there is some kind of transmission
       error. Otherwise, check the response code in the buffer. If it starts with
       '3', more data is expected. */
       if (errno != 0 || buffer[0] != '3')
               return FAIL;

       return FAIL;
}

/* End of spa.c */
Commit	Line	Data
55c75993	1	/* $Cambridge: exim/src/src/auths/spa.c,v 1.11 2010/06/05 10:16:36 pdp Exp $ */
0756eb3c PH	2
	3	/*************************************************
	4	* Exim - an Internet mail transport agent *
	5	*************************************************/
	6
0a49a7a4	7	/* Copyright (c) University of Cambridge 1995 - 2009 */
0756eb3c PH	8	/* See the file NOTICE for conditions of use and distribution. */
	9
	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.
	13
	14	References:
	15	http://www.innovation.ch/java/ntlm.html
	16	http://www.kuro5hin.org/story/2002/4/28/1436/66154
55c75993	17	http://download.microsoft.com/download/9/5/e/95ef66af-9026-4bb0-a41d-a4f81802d92c/%5bMS-SMTP%5d.pdf
0756eb3c PH	18
	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.
	23
	24	* typedef signed short int16;
	25	* typedef unsigned short uint16;
	26	* typedef unsigned uint32;
	27	* typedef unsigned char uint8;
	28
16ff981e PH	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
55c75993	32	05-June-2010: PP: handle SASL initial response
0756eb3c PH	33	*/
	34
	35
	36	#include "../exim.h"
	37	#include "spa.h"
	38
	39	/* #define DEBUG_SPA */
	40
	41	#ifdef DEBUG_SPA
	42	#define DSPA(x,y,z) debug_printf(x,y,z)
	43	#else
	44	#define DSPA(x,y,z)
	45	#endif
	46
	47	/* Options specific to the spa authentication mechanism. */
	48
	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)) }
	58	};
	59
	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. */
	62
	63	int auth_spa_options_count =
	64	sizeof(auth_spa_options)/sizeof(optionlist);
	65
	66	/* Default private options block for the contidion authentication method. */
	67
	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) */
	73	};
	74
	75
	76	/*************************************************
	77	* Initialization entry point *
	78	*************************************************/
	79
	80	/* Called for each instance, after its options have been read, to
	81	enable consistency checks to be done, or anything else that needs
	82	to be set up. */
	83
	84	void
	85	auth_spa_init(auth_instance *ablock)
	86	{
	87	auth_spa_options_block *ob =
	88	(auth_spa_options_block *)(ablock->options_block);
	89
	90	/* The public name defaults to the authenticator name */
	91
	92	if (ablock->public_name == NULL) ablock->public_name = ablock->name;
	93
	94	/* Both username and password must be set for a client */
	95
	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;
101
102	/* For a server we have just one option */
103
104	ablock->server = ob->spa_serverpassword != NULL;
105	}
106
107
108
109	/*************************************************
110	* Server entry point *
111	*************************************************/
112
113	/* For interface, see auths/README */
114
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)
119
120	int
121	auth_spa_server(auth_instance ablock, uschar data)
122	{
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;
130	uschar msgbuf[2048];
131	uschar *clearpass;
132
55c75993 PP	133	/* send a 334, MS Exchange style, and grab the client's request,
55c75993 PP	134	unless we already have it via an initial response. */
0756eb3c	135
55c75993 PP	136	if ((*data == '\0') &&
55c75993 PP	137	(auth_get_no64_data(&data, US"NTLM supported") != OK))
0756eb3c PH	138	{
	139	/* something borked */
	140	return FAIL;
	141	}
	142
85b87bc2	143	if (spa_base64_to_bits((char )(&request), sizeof(request), (const char )(data)) < 0)
0756eb3c PH	144	{
	145	DEBUG(D_auth) debug_printf("auth_spa_server(): bad base64 data in "
	146	"request: %s\n", data);
	147	return FAIL;
	148	}
	149
	150	/* create a challenge and send it back */
	151
	152	spa_build_auth_challenge(&request,&challenge);
	153	spa_bits_to_base64 (msgbuf, (unsigned char*)&challenge,
	154	spa_request_length(&challenge));
	155
	156	if (auth_get_no64_data(&data, msgbuf) != OK)
	157	{
	158	/* something borked */
	159	return FAIL;
	160	}
	161
	162	/* dump client response */
85b87bc2	163	if (spa_base64_to_bits((char )(&response), sizeof(response), (const char )(data)) < 0)
0756eb3c PH	164	{
	165	DEBUG(D_auth) debug_printf("auth_spa_server(): bad base64 data in "
	166	"response: %s\n", data);
	167	return FAIL;
	168	}
	169
0756eb3c PH	170	/***************************************************************
	171	PH 07-Aug-2003: The original code here was this:
	172
	173	Ustrcpy(msgbuf, unicodeToString(((char*)responseptr) +
	174	IVAL(&responseptr->uUser.offset,0),
	175	SVAL(&responseptr->uUser.len,0)/2) );
	176
	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. ****/
	183
	184	{
	185	int i;
	186	char p = ((char)responseptr) + IVAL(&responseptr->uUser.offset,0);
	187	int len = SVAL(&responseptr->uUser.len,0)/2;
	188
	189	if (len + 1 >= sizeof(msgbuf)) return FAIL;
	190	for (i = 0; i < len; ++i)
	191	{
	192	msgbuf[i] = *p & 0x7f;
	193	p += 2;
	194	}
	195	msgbuf[i] = 0;
	196	}
	197
	198	/***************************************************************/
	199
f78eb7c6 PH	200	/* Put the username in $auth1 and $1. The former is now the preferred variable;
	201	the latter is the original variable. */
	202
	203	auth_vars[0] = expand_nstring[1] = msgbuf;
0756eb3c PH	204	expand_nlength[1] = Ustrlen(msgbuf);
	205	expand_nmax = 1;
	206
f78eb7c6 PH	207	debug_print_string(ablock->server_debug_string); /* customized debug */
f78eb7c6 PH	208
0756eb3c PH	209	/* look up password */
	210
	211	clearpass = expand_string(ob->spa_serverpassword);
	212	if (clearpass == NULL)
	213	{
	214	if (expand_string_forcedfail)
	215	{
	216	DEBUG(D_auth) debug_printf("auth_spa_server(): forced failure while "
	217	"expanding spa_serverpassword\n");
	218	return FAIL;
	219	}
	220	else
	221	{
	222	DEBUG(D_auth) debug_printf("auth_spa_server(): error while expanding "
	223	"spa_serverpassword: %s\n", expand_string_message);
	224	return DEFER;
	225	}
	226	}
	227
	228	/* create local hash copy */
	229
	230	spa_smb_encrypt (clearpass, challenge.challengeData, lmRespData);
	231	spa_smb_nt_encrypt (clearpass, challenge.challengeData, ntRespData);
	232
	233	/* compare NT hash (LM may not be available) */
	234
	235	if (memcmp(ntRespData,
	236	((unsigned char*)responseptr)+IVAL(&responseptr->ntResponse.offset,0),
	237	24) == 0)
	238	/* success. we have a winner. */
16ff981e PH	239
	240	/* Expand server_condition as an authorization check (PH) */
	241	return auth_check_serv_cond(ablock);
0756eb3c PH	242
	243	return FAIL;
	244	}
	245
	246
	247	/*************************************************
	248	* Client entry point *
	249	*************************************************/
	250
	251	/* For interface, see auths/README */
	252
	253	int
	254	auth_spa_client(
	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 */
	261	{
	262	auth_spa_options_block *ob =
	263	(auth_spa_options_block *)(ablock->options_block);
	264	SPAAuthRequest request;
	265	SPAAuthChallenge challenge;
	266	SPAAuthResponse response;
	267	char msgbuf[2048];
	268	char *domain = NULL;
	269	char username, password;
	270
0756eb3c PH	271	/* Code added by PH to expand the options */
0756eb3c PH	272
4730f942 PH	273	buffer = 0; / Default no message when cancelled */
4730f942 PH	274
0756eb3c PH	275	username = CS expand_string(ob->spa_username);
	276	if (username == NULL)
	277	{
b1206957	278	if (expand_string_forcedfail) return CANCELLED;
0756eb3c PH	279	string_format(buffer, buffsize, "expansion of \"%s\" failed in %s "
	280	"authenticator: %s", ob->spa_username, ablock->name,
	281	expand_string_message);
	282	return ERROR;
	283	}
	284
	285	password = CS expand_string(ob->spa_password);
	286	if (password == NULL)
	287	{
b1206957	288	if (expand_string_forcedfail) return CANCELLED;
0756eb3c PH	289	string_format(buffer, buffsize, "expansion of \"%s\" failed in %s "
	290	"authenticator: %s", ob->spa_password, ablock->name,
	291	expand_string_message);
	292	return ERROR;
	293	}
	294
	295	if (ob->spa_domain != NULL)
	296	{
	297	domain = CS expand_string(ob->spa_domain);
	298	if (domain == NULL)
	299	{
b1206957	300	if (expand_string_forcedfail) return CANCELLED;
0756eb3c PH	301	string_format(buffer, buffsize, "expansion of \"%s\" failed in %s "
	302	"authenticator: %s", ob->spa_domain, ablock->name,
	303	expand_string_message);
	304	return ERROR;
	305	}
	306	}
	307
	308	/* Original code */
	309
b1206957 PH	310	if (smtp_write_command(outblock, FALSE, "AUTH %s\r\n",
	311	ablock->public_name) < 0)
	312	return FAIL_SEND;
	313
	314	/* wait for the 3XX OK message */
	315	if (!smtp_read_response(inblock, (uschar *)buffer, buffsize, '3', timeout))
	316	return FAIL;
	317
0756eb3c PH	318	DSPA("\n\n%s authenticator: using domain %s\n\n",
	319	ablock->name, domain);
	320
	321	spa_build_auth_request (&request, CS username, domain);
	322	spa_bits_to_base64 (US msgbuf, (unsigned char*)&request,
	323	spa_request_length(&request));
	324
	325	DSPA("\n\n%s authenticator: sending request (%s)\n\n", ablock->name,
	326	msgbuf);
	327
	328	/* send the encrypted password */
	329	if (smtp_write_command(outblock, FALSE, "%s\r\n", msgbuf) < 0)
	330	return FAIL_SEND;
	331
	332	/* wait for the auth challenge */
	333	if (!smtp_read_response(inblock, (uschar *)buffer, buffsize, '3', timeout))
	334	return FAIL;
	335
	336	/* convert the challenge into the challenge struct */
	337	DSPA("\n\n%s authenticator: challenge (%s)\n\n",
	338	ablock->name, buffer + 4);
85b87bc2	339	spa_base64_to_bits ((char )(&challenge), sizeof(challenge), (const char )(buffer + 4));
0756eb3c PH	340
	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,
	346	msgbuf);
	347
	348	/* send the challenge response */
	349	if (smtp_write_command(outblock, FALSE, "%s\r\n", msgbuf) < 0)
	350	return FAIL_SEND;
	351
	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))
	356	return OK;
	357
	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')
	362	return FAIL;
	363
	364	return FAIL;
	365	}
	366
	367	/* End of spa.c */