auth.c

自己精简过的PPPD代码。在嵌入中应用可以更好的发挥。比原先的小了很多

/*
 * auth.c - PPP authentication and phase control.
 *
 * Copyright (c) 1993-2002 Paul Mackerras. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. The name(s) of the authors of this software must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission.
 *
 * 3. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by Paul Mackerras
 *     <[e-mail]>".
 *
 * THE AUTHORS OF THIS SOFTWARE DISCLAIM ALL WARRANTIES WITH REGARD TO
 * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS, IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
 * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
 * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 * Derived from main.c, which is:
 *
 * Copyright (c) 1984-2000 Carnegie Mellon University. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The name "Carnegie Mellon University" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For permission or any legal
 *    details, please contact
 *      Office of Technology Transfer
 *      Carnegie Mellon University
 *      5000 Forbes Avenue
 *      Pittsburgh, PA  15213-3890
 *      [phone], fax: [phone]
 *      [e-mail]
 *
 * 4. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by Computing Services
 *     at Carnegie Mellon University (http://www.cmu.edu/computing/)."
 *
 * CARNEGIE MELLON UNIVERSITY DISCLAIMS ALL WARRANTIES WITH REGARD TO
 * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS, IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY BE LIABLE
 * FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
 * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#define RCSID	"$Id: auth.c,v 1.112 2006/06/18 11:26:00 paulus Exp $"

#include <stdio.h>
#include <stddef.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <pwd.h>
#include <grp.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <utmp.h>
#include <fcntl.h>
#if defined(_PATH_LASTLOG) && defined(__linux__)
#include <lastlog.h>
#endif

#include <netdb.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#ifdef USE_PAM
#include <security/pam_appl.h>
#endif

#ifdef HAS_SHADOW
#include <shadow.h>
#ifndef PW_PPP
#define PW_PPP PW_LOGIN
#endif
#endif
#include <time.h>

#include "pppd.h"
#include "fsm.h"
#include "lcp.h"
#include "ccp.h"
#include "ecp.h"
#include "ipcp.h"
#include "upap.h"
#include "chap-new.h"
#include "eap.h"
#ifdef CBCP_SUPPORT
#include "cbcp.h"
#endif
#include "pathnames.h"

static const char rcsid[] = RCSID;

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

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

/* The name by which the peer authenticated itself to us. */
char peer_authname[MAXNAMELEN];

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

/* Records which authentication operations have been completed. */
int auth_done[NUM_PPP];

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

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

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

/* Remote telephone number, if available */
char remote_number[MAXNAMELEN];

/* Wordlist giving remote telephone numbers which may connect. */
static struct wordlist *permitted_numbers;

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

/* 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;

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

/* 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;

/* Hook for a plugin to say if we can possibly authenticate a peer using CHAP */
int (*chap_check_hook) __P((void)) = NULL;

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

/* Hook for a plugin to say whether it is OK if the peer
   refuses to authenticate. */
int (*null_auth_hook) __P((struct wordlist **paddrs,
			   struct wordlist **popts)) = NULL;

int (*allowed_address_hook) __P((u_int32_t addr)) = NULL;

/* A notifier for when the peer has authenticated itself,
   and we are proceeding to the network phase. */
struct notifier *auth_up_notifier = NULL;

/* A notifier for when the link goes down. */
struct notifier *link_down_notifier = 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;

static int used_login;		/* peer authenticated against login database */

/*
 * Option variables.
 */
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 refuse_eap = 0;		/* Don't wanna auth. ourselves with EAP */
#ifdef CHAPMS
bool refuse_mschap = 0;		/* Don't wanna auth. ourselves with MS-CHAP */
bool refuse_mschap_v2 = 0;	/* Don't wanna auth. ourselves with MS-CHAPv2 */
#else
bool refuse_mschap = 1;		/* Don't wanna auth. ourselves with MS-CHAP */
bool refuse_mschap_v2 = 1;	/* Don't wanna auth. ourselves with MS-CHAPv2 */
#endif
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 */

static char *uafname;		/* name of most recent +ua file */

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

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

static void network_phase __P((int));
static void check_idle __P((void *));
static void connect_time_expired __P((void *));
static int  plogin __P((char *, char *, char **));
static void plogout __P((void));
static int  null_login __P((int));
static int  get_pap_passwd __P((char *));
static int  have_pap_secret __P((int *));
static int  have_chap_secret __P((char *, char *, int, int *));
static int  have_srp_secret __P((char *client, char *server, int need_ip,
    int *lacks_ipp));
static int  ip_addr_check __P((u_int32_t, struct permitted_ip *));
static int  scan_authfile __P((FILE *, char *, char *, char *,
			       struct wordlist **, struct wordlist **,
			       char *, int));
static void free_wordlist __P((struct wordlist *));
static void auth_script __P((char *));
static void auth_script_done __P((void *));
static void set_allowed_addrs __P((int, struct wordlist *, struct wordlist *));
static int  some_ip_ok __P((struct wordlist *));
static int  setupapfile __P((char **));
static int  privgroup __P((char **));
static int  set_noauth_addr __P((char **));
static int  set_permitted_number __P((char **));
static void check_access __P((FILE *, char *));
static int  wordlist_count __P((struct wordlist *));

#ifdef MAXOCTETS
static void check_maxoctets __P((void *));
#endif

/*
 * Authentication-related options.
 */
option_t auth_options[] = {
    { "auth", o_bool, &auth_required,
      "Require authentication from peer", OPT_PRIO | 1 },
    { "noauth", o_bool, &auth_required,
      "Don't require peer to authenticate", OPT_PRIOSUB | OPT_PRIV,
      &allow_any_ip },
    { "require-pap", o_bool, &lcp_wantoptions[0].neg_upap,
      "Require PAP authentication from peer",
      OPT_PRIOSUB | 1, &auth_required },
    { "+pap", o_bool, &lcp_wantoptions[0].neg_upap,
      "Require PAP authentication from peer",
      OPT_ALIAS | OPT_PRIOSUB | 1, &auth_required },
    { "require-chap", o_bool, &auth_required,
      "Require CHAP authentication from peer",
      OPT_PRIOSUB | OPT_A2OR | MDTYPE_MD5,
      &lcp_wantoptions[0].chap_mdtype },
    { "+chap", o_bool, &auth_required,
      "Require CHAP authentication from peer",
      OPT_ALIAS | OPT_PRIOSUB | OPT_A2OR | MDTYPE_MD5,
      &lcp_wantoptions[0].chap_mdtype },
#ifdef CHAPMS
    { "require-mschap", o_bool, &auth_required,
      "Require MS-CHAP authentication from peer",
      OPT_PRIOSUB | OPT_A2OR | MDTYPE_MICROSOFT,
      &lcp_wantoptions[0].chap_mdtype },
    { "+mschap", o_bool, &auth_required,
      "Require MS-CHAP authentication from peer",
      OPT_ALIAS | OPT_PRIOSUB | OPT_A2OR | MDTYPE_MICROSOFT,
      &lcp_wantoptions[0].chap_mdtype },
    { "require-mschap-v2", o_bool, &auth_required,
      "Require MS-CHAPv2 authentication from peer",
      OPT_PRIOSUB | OPT_A2OR | MDTYPE_MICROSOFT_V2,
      &lcp_wantoptions[0].chap_mdtype },
    { "+mschap-v2", o_bool, &auth_required,
      "Require MS-CHAPv2 authentication from peer",
      OPT_ALIAS | OPT_PRIOSUB | OPT_A2OR | MDTYPE_MICROSOFT_V2,
      &lcp_wantoptions[0].chap_mdtype },
#endif

    { "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", OPT_ALIAS | 1 },
    { "refuse-chap", o_bool, &refuse_chap,
      "Don't agree to auth to peer with CHAP",
      OPT_A2CLRB | MDTYPE_MD5,
      &lcp_allowoptions[0].chap_mdtype },
    { "-chap", o_bool, &refuse_chap,
      "Don't allow CHAP authentication with peer",
      OPT_ALIAS | OPT_A2CLRB | MDTYPE_MD5,
      &lcp_allowoptions[0].chap_mdtype },
#ifdef CHAPMS
    { "refuse-mschap", o_bool, &refuse_mschap,
      "Don't agree to auth to peer with MS-CHAP",
      OPT_A2CLRB | MDTYPE_MICROSOFT,
      &lcp_allowoptions[0].chap_mdtype },
    { "-mschap", o_bool, &refuse_mschap,
      "Don't allow MS-CHAP authentication with peer",
      OPT_ALIAS | OPT_A2CLRB | MDTYPE_MICROSOFT,
      &lcp_allowoptions[0].chap_mdtype },
    { "refuse-mschap-v2", o_bool, &refuse_mschap_v2,
      "Don't agree to auth to peer with MS-CHAPv2",
      OPT_A2CLRB | MDTYPE_MICROSOFT_V2,
      &lcp_allowoptions[0].chap_mdtype },
    { "-mschap-v2", o_bool, &refuse_mschap_v2,
      "Don't allow MS-CHAPv2 authentication with peer",
      OPT_ALIAS | OPT_A2CLRB | MDTYPE_MICROSOFT_V2,
      &lcp_allowoptions[0].chap_mdtype },
#endif

    { "require-eap", o_bool, &lcp_wantoptions[0].neg_eap,
      "Require EAP authentication from peer", OPT_PRIOSUB | 1,
      &auth_required },
    { "refuse-eap", o_bool, &refuse_eap,
      "Don't agree to authenticate to peer with EAP", 1 },

    { "name", o_string, our_name,
      "Set local name for authentication",
      OPT_PRIO | OPT_PRIV | OPT_STATIC, NULL, MAXNAMELEN },

    /*/{ "+ua", o_special, (void *)setupapfile,
      "Get PAP user and password from file",
      OPT_PRIO | OPT_A2STRVAL, &uafname },*/

    { "user", o_string, user,
      "Set name for auth with peer", OPT_PRIO | OPT_STATIC, NULL, MAXNAMELEN },

    { "password", o_string, passwd,
      "Password for authenticating us to the peer",
      OPT_PRIO | OPT_STATIC | OPT_HIDE, NULL, MAXSECRETLEN },

    { "usehostname", o_bool, &usehostname,
      "Must use hostname for authentication", 1 },

    { "remotename", o_string, remote_name,
      "Set remote name for authentication", OPT_PRIO | OPT_STATIC,
      &explicit_remote, MAXNAMELEN },

    { "login", o_bool, &uselogin,
      "Use system password database for PAP", 1 },

    { "papcrypt", o_bool, &cryptpap,
      "PAP passwords are encrypted", 1 },

    /*/{ "privgroup", o_special, (void *)privgroup,
      "Allow group members to use privileged options", OPT_PRIV | OPT_A2LIST },

    { "allow-ip", o_special, (void *)set_noauth_addr,
      "Set IP address(es) which can be used without authentication",
      OPT_PRIV | OPT_A2LIST },*/

    { "remotenumber", o_string, remote_number,
      "Set remote telephone number for authentication", OPT_PRIO | OPT_STATIC,
      NULL, MAXNAMELEN },

    /*/{ "allow-number", o_special, (void *)set_permitted_number,
      "Set telephone number(s) which are allowed to connect",
      OPT_PRIV | OPT_A2LIST },*/

    { NULL }
};

#ifdef INCLUDE
/*
 * setupapfile - specifies UPAP info for authenticating with peer.
 */
static int
setupapfile(argv)
    char **argv;
{
    FILE *ufile;
    int l;
    uid_t euid;
    char u[MAXNAMELEN], p[MAXSECRETLEN];
    char *fname;

    lcp_allowoptions[0].neg_upap = 1;

    /* open user info file */
    fname = strdup(*argv);
    if (fname == NULL)
	novm("+ua file name");
    euid = geteuid();
    if (seteuid(getuid()) == -1) {
	option_error("unable to reset uid before opening %s: %m", fname);
	return 0;
    }
    ufile = fopen(fname, "r");
    if (seteuid(euid) == -1)
	fatal("unable to regain privileges: %m");
    if (ufile == NULL) {
	option_error("unable to open user login data file %s", fname);
	return 0;
    }
    check_access(ufile, fname);
    uafname = fname;

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

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

    if (override_value("user", option_priority, fname))
	strlcpy(user, u, sizeof(user));
    if (override_value("passwd", option_priority, fname))
	strlcpy(passwd, p, sizeof(passwd));

    return (1);
}


/*
 * privgroup - allow members of the group to have privileged access.
 */
static int
privgroup(argv)
    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;
}


/*
 * 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(argv)
    char **argv;
{
    char *addr = *argv;
    int l = strlen(addr) + 1;
    struct wordlist *wp;

    wp = (struct wordlist *) malloc(sizeof(struct wordlist) + l);
    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;
}


/*
 * set_permitted_number - set remote telephone number(s) that may connect.
 */
static int
set_permitted_number(argv)