auth.c

基于STM32F107的UDP服务器程序

    /* no further use for the link: shut up shop. */
    lcp_close(0, "No network protocols running");
  }
}

/*
 * auth_reset - called when LCP is starting negotiations to recheck
 * authentication options, i.e. whether we have appropriate secrets
 * to use for authenticating ourselves and/or the peer.
 */
void
auth_reset(int unit)
{
  lcp_options *go = &lcp_gotoptions[unit];
  lcp_options *ao = &lcp_allowoptions[0];
  ipcp_options *ipwo = &ipcp_wantoptions[0];
  u32_t remote;

  AUTHDEBUG((LOG_INFO, "auth_reset: %d\n", unit));
  ao->neg_upap = !ppp_settings.refuse_pap && (ppp_settings.passwd[0] != 0 || get_pap_passwd(unit, NULL, NULL));
  ao->neg_chap = !ppp_settings.refuse_chap && ppp_settings.passwd[0] != 0 /*have_chap_secret(ppp_settings.user, ppp_settings.remote_name, (u32_t)0)*/;

  if (go->neg_upap && !have_pap_secret()) {
    go->neg_upap = 0;
  }
  if (go->neg_chap) {
    remote = ipwo->accept_remote? 0: ipwo->hisaddr;
    if (!have_chap_secret(ppp_settings.remote_name, ppp_settings.our_name, remote)) {
      go->neg_chap = 0;
    }
  }
}

#if PAP_SUPPORT
/*
 * check_passwd - Check the user name and passwd against the PAP secrets
 * file.  If requested, also check against the system password database,
 * and login the user if OK.
 *
 * returns:
 *  UPAP_AUTHNAK: Authentication failed.
 *  UPAP_AUTHACK: Authentication succeeded.
 * In either case, msg points to an appropriate message.
 */
int
check_passwd( int unit, char *auser, int userlen, char *apasswd, int passwdlen, char **msg, int *msglen)
{
#if 1
  LWIP_UNUSED_ARG(unit);
  LWIP_UNUSED_ARG(auser);
  LWIP_UNUSED_ARG(userlen);
  LWIP_UNUSED_ARG(apasswd);
  LWIP_UNUSED_ARG(passwdlen);
  LWIP_UNUSED_ARG(msglen);
  *msg = (char *) 0;
  return UPAP_AUTHACK;     /* XXX Assume all entries OK. */
#else
  int ret = 0;
  struct wordlist *addrs = NULL;
  char passwd[256], user[256];
  char secret[MAXWORDLEN];
  static u_short attempts = 0;
  
  /*
   * Make copies of apasswd and auser, then null-terminate them.
   */
  BCOPY(apasswd, passwd, passwdlen);
  passwd[passwdlen] = '\0';
  BCOPY(auser, user, userlen);
  user[userlen] = '\0';
  *msg = (char *) 0;

  /* XXX Validate user name and password. */
  ret = UPAP_AUTHACK;     /* XXX Assume all entries OK. */
      
  if (ret == UPAP_AUTHNAK) {
    if (*msg == (char *) 0) {
      *msg = "Login incorrect";
    }
    *msglen = strlen(*msg);
    /*
     * Frustrate passwd stealer programs.
     * Allow 10 tries, but start backing off after 3 (stolen from login).
     * On 10'th, drop the connection.
     */
    if (attempts++ >= 10) {
      AUTHDEBUG((LOG_WARNING, "%d LOGIN FAILURES BY %s\n", attempts, user));
      /*ppp_panic("Excess Bad Logins");*/
    }
    if (attempts > 3) {
      sys_msleep((attempts - 3) * 5);
    }
    if (addrs != NULL) {
      free_wordlist(addrs);
    }
  } else {
    attempts = 0; /* Reset count */
    if (*msg == (char *) 0) {
      *msg = "Login ok";
    }
    *msglen = strlen(*msg);
    set_allowed_addrs(unit, addrs);
  }

  BZERO(passwd, sizeof(passwd));
  BZERO(secret, sizeof(secret));

  return ret;
#endif
}
#endif /* PAP_SUPPORT */


/*
 * auth_ip_addr - check whether the peer is authorized to use
 * a given IP address.  Returns 1 if authorized, 0 otherwise.
 */
int
auth_ip_addr(int unit, u32_t addr)
{
  return ip_addr_check(addr, addresses[unit]);
}

/*
 * bad_ip_adrs - return 1 if the IP address is one we don't want
 * to use, such as an address in the loopback net or a multicast address.
 * addr is in network byte order.
 */
int
bad_ip_adrs(u32_t addr)
{
  addr = ntohl(addr);
  return (addr >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET
      || IN_MULTICAST(addr) || IN_BADCLASS(addr);
}


#if CHAP_SUPPORT
/*
 * get_secret - open the CHAP secret file and return the secret
 * for authenticating the given client on the given server.
 * (We could be either client or server).
 */
int get_secret( int unit, char *client, char *server, char *secret, int *secret_len, int save_addrs)
{
#if 1
  int len;
  struct wordlist *addrs;

  LWIP_UNUSED_ARG(unit);
  LWIP_UNUSED_ARG(server);
  LWIP_UNUSED_ARG(save_addrs);

  addrs = NULL;

  if(!client || !client[0] || strcmp(client, ppp_settings.user)) {
    return 0;
  }

  len = strlen(ppp_settings.passwd);
  if (len > MAXSECRETLEN) {
    AUTHDEBUG((LOG_ERR, "Secret for %s on %s is too long\n", client, server));
    len = MAXSECRETLEN;
  }

  BCOPY(ppp_settings.passwd, secret, len);
  *secret_len = len;

  return 1;
#else
  int ret = 0, len;
  struct wordlist *addrs;
  char secbuf[MAXWORDLEN];
  
  addrs = NULL;
  secbuf[0] = 0;

  /* XXX Find secret. */
  if (ret < 0) {
    return 0;
  }

  if (save_addrs) {
    set_allowed_addrs(unit, addrs);
  }

  len = strlen(secbuf);
  if (len > MAXSECRETLEN) {
    AUTHDEBUG((LOG_ERR, "Secret for %s on %s is too long\n", client, server));
    len = MAXSECRETLEN;
  }

  BCOPY(secbuf, secret, len);
  BZERO(secbuf, sizeof(secbuf));
  *secret_len = len;

  return 1;
#endif
}
#endif /* CHAP_SUPPORT */


#if 0 /* UNUSED */
/*
 * auth_check_options - called to check authentication options.
 */
void
auth_check_options(void)
{
  lcp_options *wo = &lcp_wantoptions[0];
  int can_auth;
  ipcp_options *ipwo = &ipcp_wantoptions[0];
  u32_t remote;

  /* Default our_name to hostname, and user to our_name */
  if (ppp_settings.our_name[0] == 0 || ppp_settings.usehostname) {
      strcpy(ppp_settings.our_name, ppp_settings.hostname);
  }

  if (ppp_settings.user[0] == 0) {
    strcpy(ppp_settings.user, ppp_settings.our_name);
  }

  /* If authentication is required, ask peer for CHAP or PAP. */
  if (ppp_settings.auth_required && !wo->neg_chap && !wo->neg_upap) {
    wo->neg_chap = 1;
    wo->neg_upap = 1;
  }
  
  /*
   * Check whether we have appropriate secrets to use
   * to authenticate the peer.
   */
  can_auth = wo->neg_upap && have_pap_secret();
  if (!can_auth && wo->neg_chap) {
    remote = ipwo->accept_remote? 0: ipwo->hisaddr;
    can_auth = have_chap_secret(ppp_settings.remote_name, ppp_settings.our_name, remote);
  }

  if (ppp_settings.auth_required && !can_auth) {
    ppp_panic("No auth secret");
  }
}
#endif


/**********************************/
/*** LOCAL FUNCTION DEFINITIONS ***/
/**********************************/
/*
 * Proceed to the network phase.
 */
static void
network_phase(int unit)
{
  int i;
  struct protent *protp;
  lcp_options *go = &lcp_gotoptions[unit];
  
  /*
   * If the peer had to authenticate, run the auth-up script now.
   */
  if ((go->neg_chap || go->neg_upap) && !did_authup) {
    /* XXX Do setup for peer authentication. */
    did_authup = 1;
  }

#if CBCP_SUPPORT
  /*
   * If we negotiated callback, do it now.
   */
  if (go->neg_cbcp) {
    lcp_phase[unit] = PHASE_CALLBACK;
    (*cbcp_protent.open)(unit);
    return;
  }
#endif /* CBCP_SUPPORT */

  lcp_phase[unit] = PHASE_NETWORK;
  for (i = 0; (protp = ppp_protocols[i]) != NULL; ++i) {
    if (protp->protocol < 0xC000 && protp->enabled_flag && protp->open != NULL) {
      (*protp->open)(unit);
      if (protp->protocol != PPP_CCP) {
        ++num_np_open;
      }
    }
  }

  if (num_np_open == 0) {
    /* nothing to do */
    lcp_close(0, "No network protocols running");
  }
}

/*
 * check_idle - check whether the link has been idle for long
 * enough that we can shut it down.
 */
static void
check_idle(void *arg)
{
  struct ppp_idle idle;
  u_short itime;
  
  LWIP_UNUSED_ARG(arg);
  if (!get_idle_time(0, &idle)) {
    return;
  }
  itime = LWIP_MIN(idle.xmit_idle, idle.recv_idle);
  if (itime >= ppp_settings.idle_time_limit) {
    /* link is idle: shut it down. */
    AUTHDEBUG((LOG_INFO, "Terminating connection due to lack of activity.\n"));
    lcp_close(0, "Link inactive");
  } else {
    TIMEOUT(check_idle, NULL, ppp_settings.idle_time_limit - itime);
  }
}

/*
 * connect_time_expired - log a message and close the connection.
 */
static void
connect_time_expired(void *arg)
{
  LWIP_UNUSED_ARG(arg);

  AUTHDEBUG((LOG_INFO, "Connect time expired\n"));
  lcp_close(0, "Connect time expired");   /* Close connection */
}

#if 0
/*
 * login - Check the user name and password against the system
 * password database, and login the user if OK.
 *
 * returns:
 *  UPAP_AUTHNAK: Login failed.
 *  UPAP_AUTHACK: Login succeeded.
 * In either case, msg points to an appropriate message.
 */
static int
login(char *user, char *passwd, char **msg, int *msglen)
{
  /* XXX Fail until we decide that we want to support logins. */
  return (UPAP_AUTHNAK);
}
#endif

/*
 * logout - Logout the user.
 */
static void
logout(void)
{
  logged_in = 0;
}

/*
 * null_login - Check if a username of "" and a password of "" are
 * acceptable, and iff so, set the list of acceptable IP addresses
 * and return 1.
 */
static int
null_login(int unit)
{
  LWIP_UNUSED_ARG(unit);
  /* XXX Fail until we decide that we want to support logins. */
  return 0;
}

/*
 * get_pap_passwd - get a password for authenticating ourselves with
 * our peer using PAP.  Returns 1 on success, 0 if no suitable password
 * could be found.
 */
static int
get_pap_passwd(int unit, char *user, char *passwd)
{
  LWIP_UNUSED_ARG(unit);
/* normally we would reject PAP if no password is provided,
   but this causes problems with some providers (like CHT in Taiwan)
   who incorrectly request PAP and expect a bogus/empty password, so
   always provide a default user/passwd of "none"/"none"
*/
  if(user) {
    strcpy(user, "none");
  }
  if(passwd) {
    strcpy(passwd, "none");
  }
  return 1;
}

/*
 * have_pap_secret - check whether we have a PAP file with any
 * secrets that we could possibly use for authenticating the peer.
 */
static int
have_pap_secret(void)
{
  /* XXX Fail until we set up our passwords. */
  return 0;
}

/*
 * have_chap_secret - check whether we have a CHAP file with a
 * secret that we could possibly use for authenticating `client'
 * on `server'.  Either can be the null string, meaning we don't
 * know the identity yet.
 */
static int
have_chap_secret(char *client, char *server, u32_t remote)
{
  LWIP_UNUSED_ARG(client);
  LWIP_UNUSED_ARG(server);
  LWIP_UNUSED_ARG(remote);
  /* XXX Fail until we set up our passwords. */
  return 0;
}

#if 0 /* PAP_SUPPORT || CHAP_SUPPORT */
/*
 * set_allowed_addrs() - set the list of allowed addresses.
 */
static void
set_allowed_addrs(int unit, struct wordlist *addrs)
{
  if (addresses[unit] != NULL) {
    free_wordlist(addresses[unit]);
  }
  addresses[unit] = addrs;

#if 0
  /*
   * If there's only one authorized address we might as well
   * ask our peer for that one right away
   */
  if (addrs != NULL && addrs->next == NULL) {
    char *p = addrs->word;
    struct ipcp_options *wo = &ipcp_wantoptions[unit];
    u32_t a;
    struct hostent *hp;
    
    if (wo->hisaddr == 0 && *p != '!' && *p != '-' && strchr(p, '/') == NULL) {
      hp = gethostbyname(p);
      if (hp != NULL && hp->h_addrtype == AF_INET) {
        a = *(u32_t *)hp->h_addr;
      } else {
        a = inet_addr(p);
      }
      if (a != (u32_t) -1) {
        wo->hisaddr = a;
      }
    }
  }
#endif
}
#endif /* 0 */ /* PAP_SUPPORT || CHAP_SUPPORT */

static int
ip_addr_check(u32_t addr, struct wordlist *addrs)
{
  /* don't allow loopback or multicast address */
  if (bad_ip_adrs(addr)) {
    return 0;
  }

  if (addrs == NULL) {
    return !ppp_settings.auth_required; /* no addresses authorized */
  }

  /* XXX All other addresses allowed. */
  return 1;
}

#if 0 /* PAP_SUPPORT || CHAP_SUPPORT */
/*
 * free_wordlist - release memory allocated for a wordlist.
 */
static void
free_wordlist(struct wordlist *wp)
{
  struct wordlist *next;
  
  while (wp != NULL) {
    next = wp->next;
    free(wp);
    wp = next;
  }
}
#endif  /* 0 */ /* PAP_SUPPORT || CHAP_SUPPORT */

#endif /* PPP_SUPPORT */