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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 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 program. If not, see <https://www.gnu.org/licenses/>
*
*/
/* Functions for operating in an PSK passwd file are included here */
#include "gnutls_int.h"
#include "x509_b64.h"
#include "errors.h"
#include <auth/psk_passwd.h>
#include <auth/psk.h>
#include "auth.h"
#include "dh.h"
#include "debug.h"
#include <str.h>
#include <datum.h>
#include <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;
gnutls_datum_t tmp;
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--;
tmp.data = (void*)p;
tmp.size = len;
ret = gnutls_hex_decode2(&tmp, psk);
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 = NULL;
size_t line_size = 0;
unsigned i, len;
int ret;
cred = (gnutls_psk_server_credentials_t)
_gnutls_get_cred(session, GNUTLS_CRD_PSK);
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 (getline(&line, &line_size, fd) > 0) {
/* move to first ':' */
i = 0;
while ((i < line_size) && (line[i] != '\0')
&& (line[i] != ':')) {
i++;
}
if (strncmp(username, line, MAX(i, len)) == 0) {
ret = pwd_put_values(psk, line);
if (ret < 0) {
gnutls_assert();
ret = GNUTLS_E_SRP_PWD_ERROR;
goto cleanup;
}
ret = 0;
goto cleanup;
}
}
/* user was not found. Fake him.
*/
ret = _randomize_psk(psk);
if (ret < 0) {
goto cleanup;
}
ret = 0;
cleanup:
if (fd != NULL)
fclose(fd);
zeroize_key(line, line_size);
free(line);
return ret;
}
/* returns the username and they key for the PSK session.
* Free is non (0) if they have to be freed.
*/
int _gnutls_find_psk_key(gnutls_session_t session,
gnutls_psk_client_credentials_t cred,
gnutls_datum_t * username, gnutls_datum_t * key,
int *free)
{
char *user_p;
int ret;
*free = 0;
if (cred->username.data != NULL && cred->key.data != NULL) {
username->data = cred->username.data;
username->size = cred->username.size;
key->data = cred->key.data;
key->size = cred->key.size;
} else if (cred->get_function != NULL) {
ret = cred->get_function(session, &user_p, key);
if (ret)
return gnutls_assert_val(ret);
username->data = (uint8_t *) user_p;
username->size = strlen(user_p);
*free = 1;
} else
return
gnutls_assert_val(GNUTLS_E_INSUFFICIENT_CREDENTIALS);
return 0;
}
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