/* MODULE: auth_shadow */

/* COPYRIGHT
 * Copyright (c) 1997 Messaging Direct Ltd.
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY MESSAGING DIRECT LTD. ``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 MESSAGING DIRECT LTD. OR
 * ITS EMPLOYEES OR AGENTS 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.
 * END COPYRIGHT */

#ifdef __GNUC__
#ident "$Id: auth_shadow.c,v 1.2 2002/05/23 18:58:39 snsimon Exp $"
#endif

/* PUBLIC DEPENDENCIES */
#include "mechanisms.h"

#ifdef AUTH_SHADOW

# include <unistd.h>
# include <stdlib.h>
# include <string.h>
# include <sys/types.h>
# include <time.h>
# include <pwd.h>
# include <syslog.h>
# ifndef HAVE_GETSPNAM
/* XXX Is this header only available on AIX? */
#   include <des.h>
#endif /* ! HAVE_GETSPNAM */
# ifdef HAVE_GETUSERPW
#  include <userpw.h>
#  include <usersec.h>
# else /* ! HAVE_GETUSERPW */
#  include <shadow.h>
# endif /* ! HAVE_GETUSERPW */

# include "auth_shadow.h"
# include "globals.h"
/* END PUBLIC DEPENDENCIES */

/* FUNCTION: auth_shadow */

/* SYNOPSIS
 * Authenticate against the system shadow password database. Where
 * possible (and if enabled by the command line arguments), enforce
 * time-of-day and other login restrictions.
 */

char *					/* R: allocated response string */
auth_shadow (
  /* PARAMETERS */
  const char *login,			/* I: plaintext authenticator */
  const char *password,			/* I: plaintext password */
  const char *service __attribute__((unused)),
  const char *realm __attribute__((unused))
  /* END PARAMETERS */
  )
{

/************************************************************************
 *									*
 * This is gross. Everyone wants to do this differently, thus we have   *
 * to #ifdef the whole mess for each system type.                       *
 *									*
 ***********************************************************************/

# ifdef HAVE_GETSPNAM

/**************
 * getspnam() *
 *************/

    /* VARIABLES */
    struct passwd	*pw;		/* return from getpwent() */
    struct spwd   	*sp;		/* return from getspnam() */
    long today;				/* the current time */
    char *cpw;				/* pointer to crypt() result */
    /* END VARIABLES */

#  define RETURN(x) return strdup(x)

    /*
     * "Magic" password field entries for SunOS.
     *
     * *LK* is hinted at in the shadow(4) man page, but the
     * only definition for it (that I could find) is in the passmgmt(1M)
     * man page.
     *
     * *NP* is documented in getspnam(3) and indicates the caller had
     * insufficient permission to read the shadow password database
     * (generally this is a NIS error).
     */

#  define SHADOW_PW_LOCKED "*LK*"	/* account locked (not used by us) */
#  define SHADOW_PW_EPERM  "*NP*"	/* insufficient database perms */

    pw = getpwnam(login);
    endpwent();
    if (pw == NULL) {
	if (debug) {
	    syslog(LOG_DEBUG, "DEBUG: auth_shadow: getpwnam(%s) returned NULL", login);
	}
	RETURN("NO");
    }

    today = (long)time(NULL)/(24L*60*60);

    sp = getspnam(login);
    endspent();

    if (sp == NULL) {
	if (debug) {
	    syslog(LOG_DEBUG, "DEBUG: auth_shadow: getspnam(%s) returned NULL", login);
	}
	RETURN("NO");
    }

    if (!strcmp(sp->sp_pwdp, SHADOW_PW_EPERM)) {
	if (debug) {
	    syslog(LOG_DEBUG, "DEBUG: auth_shadow: sp->sp_pwdp == SHADOW_PW_EPERM");
	}
	RETURN("NO Insufficient permission to access NIS authentication database (saslauthd)");
    }

    /*
     * Note: no check for SHADOW_PW_LOCKED. Returning a "locked" notification
     * would allow login-id namespace probes, and violates our policy of
     * not returning any information about a login until we have validated
     * the password.
     */
    cpw = strdup((const char *)crypt(password, sp->sp_pwdp));
    if (strcmp(sp->sp_pwdp, cpw)) {
	if (debug) {
	    syslog(LOG_DEBUG, "DEBUG: auth_shadow: pw mismatch: '%s' != '%s'",
		   sp->sp_pwdp, cpw);
	}
	free(cpw);
	RETURN("NO");
    }
    free(cpw);

    /*
     * The following fields will be set to -1 if:
     *
     *	1) They are not specified in the shadow database, or
     *	2) The database is being served up by NIS.
     */

    if ((sp->sp_expire != -1) && (today > sp->sp_expire)) {
	if (debug) {
	    syslog(LOG_DEBUG, "DEBUG: auth_shadow: account expired: %dl > %dl",
		   today, sp->sp_expire);
	}
	RETURN("NO Account expired");
    }

    /* Remaining tests are relative to the last change date for the password */

    if (sp->sp_lstchg != -1) {

	if ((sp->sp_max != -1) && ((sp->sp_lstchg + sp->sp_max) < today)) {
	    if (debug) {
		syslog(LOG_DEBUG,
		       "DEBUG: auth_shadow: password expired: %ld + %ld < %ld",
		       sp->sp_lstchg, sp->sp_max, today);
	    }
	    RETURN("NO Password expired");
	}
    }
    if (debug) {
	syslog(LOG_DEBUG, "DEBUG: auth_shadow: OK: %s", login);
    }
    RETURN("OK");


# elif defined(HAVE_GETUSERPW)

/*************
 * AIX 4.1.4 *
 ************/
    /* VARIABLES */
    struct userpw *upw;				/* return from getuserpw() */
    /* END VARIABLES */

#  define RETURN(x) { endpwdb(); return strdup(x); }

    if (setpwdb(S_READ) == -1) {
	syslog(LOG_ERR, "setpwdb: %m");
	RETURN("NO setpwdb() internal failure (saslauthd)");
    }
  
    upw = getuserpw(login);
  
    if (upw == 0) {
	if (debug) {
	    syslog(LOG_DEBUG, "auth_shadow: getuserpw(%s) == 0",
		   login);
	}
	RETURN("NO");
    }
  
    if (strcmp(upw->upw_passwd, crypt(password, upw->upw_passwd)) != 0) {
	if (debug) {
	    syslog(LOG_DEBUG, "auth_shadow: pw mismatch: %s != %s",
		   password, upw->upw_passwd);
	}
	RETURN("NO");
    }

    RETURN("OK");
  
# else /* HAVE_GETUSERPW */

#  error "unknown shadow authentication type"

# endif /* ! HAVE_GETUSERPW */
}

#else /* !AUTH_SHADOW */

char *
auth_shadow (
  const char *login __attribute__((unused)),
  const char *passwd __attribute__((unused)),
  const char *service __attribute__((unused)),
  const char *realm __attribute__((unused))
  )
{
    return NULL;
}

#endif /* !AUTH_SHADOW */

/* END FUNCTION: auth_shadow */

/* END MODULE: auth_shadow */
