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/*
* Copyright (C) 2005-2012 Free Software Foundation, Inc.
*
* Author: Nikos Mavrogiannopoulos
*
* This file is part of GnuTLS.
*
* The GnuTLS 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 3 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 program. If not, see <http://www.gnu.org/licenses/>
*
*/
/* Functions for operating in an PSK passwd file are included here */
#include <gnutls_int.h>
#ifdef ENABLE_PSK
#include "x509_b64.h"
#include "gnutls_errors.h"
#include <auth/psk_passwd.h>
#include <auth/psk.h>
#include "gnutls_auth.h"
#include "gnutls_dh.h"
#include "debug.h"
#include <gnutls_str.h>
#include <gnutls_datum.h>
#include <gnutls_num.h>
#include <random.h>
/* this function parses passwd.psk file. Format is:
* string(username):hex(passwd)
*/
static int
pwd_put_values (gnutls_datum_t * psk, char *str)
{
char *p;
int len, ret;
size_t size;
p = strchr (str, ':');
if (p == NULL)
{
gnutls_assert ();
return GNUTLS_E_SRP_PWD_PARSING_ERROR;
}
*p = '\0';
p++;
/* skip username
*/
/* read the key
*/
len = strlen (p);
if (p[len - 1] == '\n' || p[len - 1] == ' ')
len--;
size = psk->size = len / 2;
psk->data = gnutls_malloc (size);
if (psk->data == NULL)
{
gnutls_assert ();
return GNUTLS_E_MEMORY_ERROR;
}
ret = _gnutls_hex2bin (p, len, psk->data, &size);
psk->size = (unsigned int) size;
if (ret < 0)
{
gnutls_assert ();
return ret;
}
return 0;
}
/* Randomizes the given password entry. It actually sets a random password.
* Returns 0 on success.
*/
static int
_randomize_psk (gnutls_datum_t * psk)
{
int ret;
psk->data = gnutls_malloc (16);
if (psk->data == NULL)
{
gnutls_assert ();
return GNUTLS_E_MEMORY_ERROR;
}
psk->size = 16;
ret = _gnutls_rnd (GNUTLS_RND_NONCE, (char *) psk->data, 16);
if (ret < 0)
{
gnutls_assert ();
return ret;
}
return 0;
}
/* Returns the PSK key of the given user.
* If the user doesn't exist a random password is returned instead.
*/
int
_gnutls_psk_pwd_find_entry (gnutls_session_t session, char *username,
gnutls_datum_t * psk)
{
gnutls_psk_server_credentials_t cred;
FILE *fd;
char line[2 * 1024];
unsigned i, len;
int ret;
cred = (gnutls_psk_server_credentials_t)
_gnutls_get_cred (session, GNUTLS_CRD_PSK, NULL);
if (cred == NULL)
{
gnutls_assert ();
return GNUTLS_E_INSUFFICIENT_CREDENTIALS;
}
/* if the callback which sends the parameters is
* set, use it.
*/
if (cred->pwd_callback != NULL)
{
ret = cred->pwd_callback (session, username, psk);
if (ret == 1)
{ /* the user does not exist */
ret = _randomize_psk (psk);
if (ret < 0)
{
gnutls_assert ();
return ret;
}
return 0;
}
if (ret < 0)
{
gnutls_assert ();
return GNUTLS_E_SRP_PWD_ERROR;
}
return 0;
}
/* The callback was not set. Proceed.
*/
if (cred->password_file == NULL)
{
gnutls_assert ();
return GNUTLS_E_SRP_PWD_ERROR;
}
/* Open the selected password file.
*/
fd = fopen (cred->password_file, "r");
if (fd == NULL)
{
gnutls_assert ();
return GNUTLS_E_SRP_PWD_ERROR;
}
len = strlen (username);
while (fgets (line, sizeof (line), fd) != NULL)
{
/* move to first ':' */
i = 0;
while ((line[i] != ':') && (line[i] != '\0') && (i < sizeof (line)))
{
i++;
}
if (strncmp (username, line, MAX (i, len)) == 0)
{
ret = pwd_put_values (psk, line);
fclose (fd);
if (ret < 0)
{
gnutls_assert ();
return GNUTLS_E_SRP_PWD_ERROR;
}
return 0;
}
}
fclose (fd);
/* user was not found. Fake him.
* the last index found and randomize the entry.
*/
ret = _randomize_psk (psk);
if (ret < 0)
{
gnutls_assert ();
return ret;
}
return 0;
}
#endif /* ENABLE PSK */
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