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/*
* This file is part of libESMTP, a library for submission of RFC 2822
* formatted electronic mail messages using the SMTP protocol described
* in RFC 2821.
*
* Copyright (C) 2001,2002 Brian Stafford <brian@stafford.uklinux.net>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <assert.h>
#include <string.h>
#include <stdlib.h>
#include <sys/types.h>
#include "hmacmd5.h"
#include "auth-client.h"
#include "auth-plugin.h"
#define NELT(x) (sizeof x / sizeof x[0])
static int crammd5_init (void *pctx);
static void crammd5_destroy (void *ctx);
static const char *crammd5_response (void *ctx,
const char *challenge, int *len,
auth_interact_t interact, void *arg);
const struct auth_client_plugin sasl_client =
{
/* Plugin information */
"CRAM-MD5",
"Challenge-Response Authentication Mechanism (RFC 2195)",
/* Plugin instance */
crammd5_init,
crammd5_destroy,
/* Authentication */
crammd5_response,
0,
/* Security Layer */
0,
NULL,
NULL,
};
static const struct auth_client_request client_request[] =
{
{ "user", AUTH_CLEARTEXT | AUTH_USER, "User Name", 0, },
{ "passphrase", AUTH_PASS, "Pass Phrase", 0, },
};
struct crammd5_context
{
int state;
char *response;
int response_len;
};
static int
crammd5_init (void *pctx)
{
struct crammd5_context *context;
context = malloc (sizeof (struct crammd5_context));
memset (context, 0, sizeof (struct crammd5_context));
*(void **) pctx = context;
return 1;
}
static void
crammd5_destroy (void *ctx)
{
struct crammd5_context *context = ctx;
if (context->response != NULL)
{
memset (context->response, 0, context->response_len);
free (context->response);
}
free (context);
}
static const char *
crammd5_response (void *ctx, const char *challenge, int *len,
auth_interact_t interact, void *arg)
{
struct crammd5_context *context = ctx;
char *result[NELT (client_request)];
unsigned char digest[16];
char *p, *response;
int response_len;
size_t i;
static const char hex[] = "0123456789abcdef";
switch (context->state)
{
case 0: /* No initial response */
context->state = 1;
*len = 0;
return NULL;
case 1: /* Digest the challenge and compute a response. */
if (!(*interact) (client_request, result, NELT (client_request), arg))
break;
hmac_md5 (challenge, *len, result[1], strlen (result[1]), digest);
response_len = strlen (result[0]) + 1 + 2 * sizeof digest;
response = malloc (response_len);
strcpy (response, result[0]);
strcat (response, " ");
p = strchr (response, '\0');
for (i = 0; i < sizeof digest; i++)
{
*p++ = hex[(digest[i] >> 4) & 0x0F];
*p++ = hex[digest[i] & 0x0F];
}
/* Note no \0 termination */
context->state = -1;
context->response = response;
context->response_len = response_len;
*len = response_len;
return response;
}
*len = 0;
return NULL;
}
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