sane-project-backends/sanei/sanei_auth.c

284 wiersze
6.6 KiB
C

/* sane - Scanner Access Now Easy.
Copyright (C) 2000 Jochen Eisinger <jochen.eisinger@gmx.net>
This file is part of the SANE package.
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
This program 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
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston,
MA 02111-1307, USA.
As a special exception, the authors of SANE give permission for
additional uses of the libraries contained in this release of SANE.
The exception is that, if you link a SANE library with other files
to produce an executable, this does not by itself cause the
resulting executable to be covered by the GNU General Public
License. Your use of that executable is in no way restricted on
account of linking the SANE library code into it.
This exception does not, however, invalidate any other reasons why
the executable file might be covered by the GNU General Public
License.
If you submit changes to SANE to the maintainers to be included in
a subsequent release, you agree by submitting the changes that
those changes may be distributed with this exception intact.
If you write modifications of your own for SANE, it is your choice
whether to permit this exception to apply to your modifications.
If you do not wish that, delete this exception notice.
This file implements an interface for user authorization using MD5 digest */
#include "../include/sane/config.h"
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <time.h>
#define BACKEND_NAME sanei_auth
#include "../include/sane/sanei_backend.h"
#include "../include/sane/sanei_debug.h"
#include "../include/sane/sane.h"
#include "../include/sane/sanei.h"
#include "../include/sane/sanei_auth.h"
#include "../include/sane/sanei_config.h"
#include "../include/md5.h"
static int random_seeded = 0;
#define INIT_RND() do { \
if (random_seeded == 0) { \
random_seeded = 1; \
srand(time(NULL)); \
DBG_INIT(); \
} \
} while (0)
#ifdef HAVE_DEV_URANDOM
static unsigned long
randombits (void)
{
FILE *dev_urandom;
unsigned long result = 0;
char buffer[4];
if ((dev_urandom = fopen ("/dev/urandom", "r")) == NULL)
{
DBG (2, "randombits: could not open /dev/urandom...\n");
return rand ();
}
fread (buffer, 1, 4, dev_urandom);
fclose (dev_urandom);
result = buffer[0];
result <<= 8;
result += buffer[1];
result <<= 8;
result += buffer[2];
result <<= 8;
result += buffer[3];
return result;
}
#else
#define randombits rand
#endif
static int
check_passwd (const char *upassword,
const char *password,
const char *randomstring, const char *username)
{
unsigned char md5digest[16];
char tmpstr[512];
if (strncmp (upassword, "$MD5$", 5) == 0)
{
sprintf (tmpstr, "%s%.128s",
strstr (randomstring, "$MD5$") + 5, password);
md5_buffer (tmpstr, strlen (tmpstr), md5digest);
sprintf (tmpstr, "$MD5$%02x%02x%02x%02x%02x%02x%02x%02x"
"%02x%02x%02x%02x%02x%02x%02x%02x",
md5digest[0], md5digest[1],
md5digest[2], md5digest[3],
md5digest[4], md5digest[5],
md5digest[6], md5digest[7],
md5digest[8], md5digest[9],
md5digest[10], md5digest[11],
md5digest[12], md5digest[13], md5digest[14], md5digest[15]);
return (strcmp (upassword, tmpstr) == 0);
}
else
{
DBG (1, "check_passwd: received plain-text reply from user ``%s''\n",
username);
return (strcmp (upassword, password) == 0);
}
}
SANE_Status
sanei_authorize (const char *resource,
const char *backend, SANE_Auth_Callback authorize)
{
FILE *passwd_file;
char passwd_filename[256];
char line[1024], *linep;
SANE_Bool entry_found = SANE_FALSE;
char md5resource[256];
char username[SANE_MAX_USERNAME_LEN];
char password[SANE_MAX_PASSWORD_LEN];
INIT_RND ();
DBG (4, "called for ``%s'' by %s\n", resource, backend);
if (strlen (resource) > 127)
DBG (1, "resource is longer than 127 chars...\n");
sprintf (passwd_filename, "%s.users", backend);
passwd_file = sanei_config_open (passwd_filename);
if (passwd_file == NULL)
{
DBG (3, "could not open ``%s''...\n", passwd_filename);
return SANE_STATUS_GOOD;
}
while (sanei_config_read (line, 1024, passwd_file))
{
if (strchr (line, ':') != NULL)
{
if (strchr (strchr (line, ':') + 1, ':') != NULL)
{
if (strcmp (strchr (strchr (line, ':') + 1, ':') + 1, resource)
== 0)
{
entry_found = SANE_TRUE;
break;
}
}
}
}
if (entry_found == SANE_FALSE)
{
fclose (passwd_file);
DBG (3, "could not find resource ``%s''...\n", resource);
return SANE_STATUS_GOOD;
}
if (authorize == NULL)
{
DBG (2, "no authorization callback supplied by frontend\n");
return SANE_STATUS_ACCESS_DENIED;
}
sprintf (md5resource, "%.128s$MD5$%x%lx%08lx",
resource, getpid (), (long int) time (NULL), randombits ());
DBG(0, "resource=%s\n", md5resource);
memset (username, 0, SANE_MAX_USERNAME_LEN);
memset (password, 0, SANE_MAX_PASSWORD_LEN);
(*authorize) (md5resource, username, password);
fseek (passwd_file, 0L, SEEK_SET);
while (sanei_config_read (line, 1024, passwd_file))
{
if ((strlen (line) > 0) && (line[strlen (line) - 1] == '\n'))
line[strlen (line) - 1] = '\n';
if ((strlen (line) > 0) && (line[strlen (line) - 1] == '\r'))
line[strlen (line) - 1] = '\r';
if ((strncmp (line, username, strlen (username)) == 0) &&
(((strchr (line, ':')) - line) == (signed) strlen (username)))
{
linep = strchr (line, ':') + 1;
if ((strchr (linep, ':') != NULL)
&& (strcmp (strchr (linep, ':') + 1, resource) == 0))
{
*(strchr (linep, ':')) = 0;
if (check_passwd (password, linep, md5resource, username))
{
fclose (passwd_file);
DBG (2, "authorization succeeded\n");
return SANE_STATUS_GOOD;
}
}
}
}
fclose (passwd_file);
DBG (1, "authorization failed\n");
return SANE_STATUS_ACCESS_DENIED;
}