auth.c

lwip-1.4.0

/*****************************************************************************
* auth.c - Network Authentication and Phase Control program file.
*
* Copyright (c) 2003 by Marc Boucher, Services Informatiques (MBSI) inc.
* Copyright (c) 1997 by Global Election Systems Inc.  All rights reserved.
*
* The authors hereby grant permission to use, copy, modify, distribute,
* and license this software and its documentation for any purpose, provided
* that existing copyright notices are retained in all copies and that this
* notice and the following disclaimer are included verbatim in any 
* distributions. No written agreement, license, or royalty fee is required
* for any of the authorized uses.
*
* THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS *AS IS* AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
* IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
******************************************************************************
* REVISION HISTORY
*
* 03-01-01 Marc Boucher <[e-mail]>
*   Ported to lwIP.
* 97-12-08 Guy Lancaster <[e-mail]>, Global Election Systems Inc.
*   Ported from public pppd code.
*****************************************************************************/
/*
 * auth.c - PPP authentication and phase control.
 *
 * Copyright (c) 1993 The Australian National University.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that the above copyright notice and this paragraph are
 * duplicated in all such forms and that any documentation,
 * advertising materials, and other materials related to such
 * distribution and use acknowledge that the software was developed
 * by the Australian National University.  The name of the University
 * may not be used to endorse or promote products derived from this
 * software without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 *
 * Copyright (c) 1989 Carnegie Mellon University.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that the above copyright notice and this paragraph are
 * duplicated in all such forms and that any documentation,
 * advertising materials, and other materials related to such
 * distribution and use acknowledge that the software was developed
 * by Carnegie Mellon University.  The name of the
 * University may not be used to endorse or promote products derived
 * from this software without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#include "lwip/opt.h"

#if PPP_SUPPORT /* don't build if not configured for use in lwipopts.h */

#include "ppp.h"
#include "pppdebug.h"

#include "fsm.h"
#include "lcp.h"
#include "pap.h"
#include "chap.h"
#include "auth.h"
#include "ipcp.h"

#if CBCP_SUPPORT
#include "cbcp.h"
#endif /* CBCP_SUPPORT */

#include "lwip/inet.h"

#include <string.h>

#if 0 /* UNUSED */
/* Bits in scan_authfile return value */
#define NONWILD_SERVER  1
#define NONWILD_CLIENT  2

#define ISWILD(word)  (word[0] == '*' && word[1] == 0)
#endif /* UNUSED */

#if PAP_SUPPORT || CHAP_SUPPORT
/* The name by which the peer authenticated itself to us. */
static char peer_authname[MAXNAMELEN];
#endif /* PAP_SUPPORT || CHAP_SUPPORT */

/* Records which authentication operations haven't completed yet. */
static int auth_pending[NUM_PPP];

/* Set if we have successfully called plogin() */
static int logged_in;

/* Set if we have run the /etc/ppp/auth-up script. */
static int did_authup; /* @todo, we don't need this in lwip*/

/* List of addresses which the peer may use. */
static struct wordlist *addresses[NUM_PPP];

#if 0 /* UNUSED */
/* Wordlist giving addresses which the peer may use
   without authenticating itself. */
static struct wordlist *noauth_addrs;

/* Extra options to apply, from the secrets file entry for the peer. */
static struct wordlist *extra_options;
#endif /* UNUSED */

/* Number of network protocols which we have opened. */
static int num_np_open;

/* Number of network protocols which have come up. */
static int num_np_up;

#if PAP_SUPPORT || CHAP_SUPPORT
/* Set if we got the contents of passwd[] from the pap-secrets file. */
static int passwd_from_file;
#endif /* PAP_SUPPORT || CHAP_SUPPORT */

#if 0 /* UNUSED */
/* Set if we require authentication only because we have a default route. */
static bool default_auth;

/* Hook to enable a plugin to control the idle time limit */
int (*idle_time_hook) __P((struct ppp_idle *)) = NULL;

/* Hook for a plugin to say whether we can possibly authenticate any peer */
int (*pap_check_hook) __P((void)) = NULL;

/* Hook for a plugin to check the PAP user and password */
int (*pap_auth_hook) __P((char *user, char *passwd, char **msgp,
        struct wordlist **paddrs,
        struct wordlist **popts)) = NULL;

/* Hook for a plugin to know about the PAP user logout */
void (*pap_logout_hook) __P((void)) = NULL;

/* Hook for a plugin to get the PAP password for authenticating us */
int (*pap_passwd_hook) __P((char *user, char *passwd)) = NULL;

/*
 * This is used to ensure that we don't start an auth-up/down
 * script while one is already running.
 */
enum script_state {
    s_down,
    s_up
};

static enum script_state auth_state = s_down;
static enum script_state auth_script_state = s_down;
static pid_t auth_script_pid = 0;

/*
 * Option variables.
 * lwip: some of these are present in the ppp_settings structure
 */
bool uselogin = 0;            /* Use /etc/passwd for checking PAP */
bool cryptpap = 0;            /* Passwords in pap-secrets are encrypted */
bool refuse_pap = 0;          /* Don't wanna auth. ourselves with PAP */
bool refuse_chap = 0;         /* Don't wanna auth. ourselves with CHAP */
bool usehostname = 0;         /* Use hostname for our_name */
bool auth_required = 0;       /* Always require authentication from peer */
bool allow_any_ip = 0;        /* Allow peer to use any IP address */
bool explicit_remote = 0;     /* User specified explicit remote name */
char remote_name[MAXNAMELEN]; /* Peer's name for authentication */

#endif /* UNUSED */

/* Bits in auth_pending[] */
#define PAP_WITHPEER    1
#define PAP_PEER        2
#define CHAP_WITHPEER   4
#define CHAP_PEER       8

/* @todo, move this somewhere */
/* Used for storing a sequence of words.  Usually malloced. */
struct wordlist {
  struct wordlist *next;
  char        word[1];
};


extern char *crypt (const char *, const char *);

/* Prototypes for procedures local to this file. */

static void network_phase (int);
static void check_idle (void *);
static void connect_time_expired (void *);
#if 0
static int  plogin (char *, char *, char **, int *);
#endif
static void plogout (void);
static int  null_login (int);
static int  get_pap_passwd (int, char *, char *);
static int  have_pap_secret (void);
static int  have_chap_secret (char *, char *, u32_t);
static int  ip_addr_check (u32_t, struct wordlist *);

#if 0 /* PAP_SUPPORT || CHAP_SUPPORT */
static int  scan_authfile (FILE *, char *, char *, char *,
             struct wordlist **, struct wordlist **,
             char *);
static void free_wordlist (struct wordlist *);
static void auth_script (char *);
static void auth_script_done (void *);
static void set_allowed_addrs (int unit, struct wordlist *addrs);
static int  some_ip_ok (struct wordlist *);
static int  setupapfile (char **);
static int  privgroup (char **);
static int  set_noauth_addr (char **);
static void check_access (FILE *, char *);
#endif /* 0 */ /* PAP_SUPPORT || CHAP_SUPPORT */

#if 0 /* UNUSED */
/*
 * Authentication-related options.
 */
option_t auth_options[] = {
    { "require-pap", o_bool, &lcp_wantoptions[0].neg_upap,
      "Require PAP authentication from peer", 1, &auth_required },
    { "+pap", o_bool, &lcp_wantoptions[0].neg_upap,
      "Require PAP authentication from peer", 1, &auth_required },
    { "refuse-pap", o_bool, &refuse_pap,
      "Don't agree to auth to peer with PAP", 1 },
    { "-pap", o_bool, &refuse_pap,
      "Don't allow PAP authentication with peer", 1 },
    { "require-chap", o_bool, &lcp_wantoptions[0].neg_chap,
      "Require CHAP authentication from peer", 1, &auth_required },
    { "+chap", o_bool, &lcp_wantoptions[0].neg_chap,
      "Require CHAP authentication from peer", 1, &auth_required },
    { "refuse-chap", o_bool, &refuse_chap,
      "Don't agree to auth to peer with CHAP", 1 },
    { "-chap", o_bool, &refuse_chap,
      "Don't allow CHAP authentication with peer", 1 },
    { "name", o_string, our_name,
      "Set local name for authentication",
      OPT_PRIV|OPT_STATIC, NULL, MAXNAMELEN },
    { "user", o_string, user,
      "Set name for auth with peer", OPT_STATIC, NULL, MAXNAMELEN },
    { "usehostname", o_bool, &usehostname,
      "Must use hostname for authentication", 1 },
    { "remotename", o_string, remote_name,
      "Set remote name for authentication", OPT_STATIC,
      &explicit_remote, MAXNAMELEN },
    { "auth", o_bool, &auth_required,
      "Require authentication from peer", 1 },
    { "noauth", o_bool, &auth_required,
      "Don't require peer to authenticate", OPT_PRIV, &allow_any_ip },
    {  "login", o_bool, &uselogin,
      "Use system password database for PAP", 1 },
    { "papcrypt", o_bool, &cryptpap,
      "PAP passwords are encrypted", 1 },
    { "+ua", o_special, (void *)setupapfile,
      "Get PAP user and password from file" },
    { "password", o_string, passwd,
      "Password for authenticating us to the peer", OPT_STATIC,
      NULL, MAXSECRETLEN },
    { "privgroup", o_special, (void *)privgroup,
      "Allow group members to use privileged options", OPT_PRIV },
    { "allow-ip", o_special, (void *)set_noauth_addr,
      "Set IP address(es) which can be used without authentication",
      OPT_PRIV },
    { NULL }
};
#endif /* UNUSED */
#if 0 /* UNUSED */
/*
 * setupapfile - specifies UPAP info for authenticating with peer.
 */
static int
setupapfile(char **argv)
{
    FILE * ufile;
    int l;

    lcp_allowoptions[0].neg_upap = 1;

    /* open user info file */
    seteuid(getuid());
    ufile = fopen(*argv, "r");
    seteuid(0);
    if (ufile == NULL) {
      option_error("unable to open user login data file %s", *argv);
      return 0;
    }
    check_access(ufile, *argv);

    /* get username */
    if (fgets(user, MAXNAMELEN - 1, ufile) == NULL
        || fgets(passwd, MAXSECRETLEN - 1, ufile) == NULL){
      option_error("unable to read user login data file %s", *argv);
      return 0;
    }
    fclose(ufile);

    /* get rid of newlines */
    l = strlen(user);
    if (l > 0 && user[l-1] == '\n')
      user[l-1] = 0;
    l = strlen(passwd);
    if (l > 0 && passwd[l-1] == '\n')
      passwd[l-1] = 0;

    return (1);
}
#endif /* UNUSED */

#if 0 /* UNUSED */
/*
 * privgroup - allow members of the group to have privileged access.
 */
static int
privgroup(char **argv)
{
    struct group *g;
    int i;

    g = getgrnam(*argv);
    if (g == 0) {
      option_error("group %s is unknown", *argv);
      return 0;
    }
    for (i = 0; i < ngroups; ++i) {
      if (groups[i] == g->gr_gid) {
        privileged = 1;
        break;
      }
    }
    return 1;
}
#endif

#if 0 /* UNUSED */
/*
 * set_noauth_addr - set address(es) that can be used without authentication.
 * Equivalent to specifying an entry like `"" * "" addr' in pap-secrets.
 */
static int
set_noauth_addr(char **argv)
{
    char *addr = *argv;
    int l = strlen(addr);
    struct wordlist *wp;

    wp = (struct wordlist *) malloc(sizeof(struct wordlist) + l + 1);
    if (wp == NULL)
      novm("allow-ip argument");
    wp->word = (char *) (wp + 1);
    wp->next = noauth_addrs;
    BCOPY(addr, wp->word, l);
    noauth_addrs = wp;
    return 1;
}
#endif /* UNUSED */

/*
 * An Open on LCP has requested a change from Dead to Establish phase.
 * Do what's necessary to bring the physical layer up.
 */
void
link_required(int unit)
{
  LWIP_UNUSED_ARG(unit);

  AUTHDEBUG(LOG_INFO, ("link_required: %d\n", unit));
}

/*
 * LCP has terminated the link; go to the Dead phase and take the
 * physical layer down.
 */
void
link_terminated(int unit)
{
  AUTHDEBUG(LOG_INFO, ("link_terminated: %d\n", unit));
  if (lcp_phase[unit] == PHASE_DEAD) {
    return;
  }
  if (logged_in) {
    plogout();
  }
  lcp_phase[unit] = PHASE_DEAD;
  AUTHDEBUG(LOG_NOTICE, ("Connection terminated.\n"));
  pppLinkTerminated(unit);
}

/*
 * LCP has gone down; it will either die or try to re-establish.
 */
void
link_down(int unit)
{
  int i;
  struct protent *protp;

  AUTHDEBUG(LOG_INFO, ("link_down: %d\n", unit));

  if (did_authup) {
    /* XXX Do link down processing. */
    did_authup = 0;
  }
  for (i = 0; (protp = ppp_protocols[i]) != NULL; ++i) {
    if (!protp->enabled_flag) {
      continue;
    }
    if (protp->protocol != PPP_LCP && protp->lowerdown != NULL) {
      (*protp->lowerdown)(unit);
    }
    if (protp->protocol < 0xC000 && protp->close != NULL) {
      (*protp->close)(unit, "LCP down");
    }
  }
  num_np_open = 0;  /* number of network protocols we have opened */
  num_np_up = 0;    /* Number of network protocols which have come up */

  if (lcp_phase[unit] != PHASE_DEAD) {
    lcp_phase[unit] = PHASE_TERMINATE;
  }
  pppLinkDown(unit);
}

/*
 * The link is established.
 * Proceed to the Dead, Authenticate or Network phase as appropriate.
 */
void
link_established(int unit)
{
  int auth;