240 lines
6.6 KiB
C
240 lines
6.6 KiB
C
/*
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* Copyright (c) 1990 - 1994, Julianne Frances Haugh
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* Copyright (c) 1996 - 2000, Marek Michałkiewicz
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* Copyright (c) 2002 - 2005, Tomasz Kłoczko
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* Copyright (c) 2007 - 2008, Nicolas François
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the copyright holders or contributors may not be used to
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* endorse or promote products derived from this software without
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* specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
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* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <config.h>
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#include <errno.h>
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#include <grp.h>
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#include <pwd.h>
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#include <stdio.h>
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#include <sys/types.h>
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#include "defines.h"
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#include "prototypes.h"
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#ifndef SUAUTHFILE
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#define SUAUTHFILE "/etc/suauth"
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#endif
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#define NOACTION 0
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#define NOPWORD 1
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#define DENY -1
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#define OWNPWORD 2
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#ifdef SU_ACCESS
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/* Really, I could do with a few const char's here defining all the
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* strings output to the user or the syslog. -- chris
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*/
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static int applies (const char *, char *);
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static int isgrp (const char *, const char *);
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static int lines = 0;
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int check_su_auth (const char *actual_id,
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const char *wanted_id,
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bool su_to_root)
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{
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int posn, endline;
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const char field[] = ":";
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FILE *authfile_fd;
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char temp[1024];
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char *to_users;
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char *from_users;
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char *action;
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if (!(authfile_fd = fopen (SUAUTHFILE, "r"))) {
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int err = errno;
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/*
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* If the file doesn't exist - default to the standard su
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* behaviour (no access control). If open fails for some
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* other reason - maybe someone is trying to fool us with
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* file descriptors limit etc., so deny access. --marekm
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*/
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if (ENOENT == err) {
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return NOACTION;
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}
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SYSLOG ((LOG_ERR,
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"could not open/read config file '%s': %s\n",
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SUAUTHFILE, strerror (err)));
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return DENY;
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}
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while (fgets (temp, sizeof (temp), authfile_fd) != NULL) {
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lines++;
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if (temp[endline = strlen (temp) - 1] != '\n') {
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SYSLOG ((LOG_ERR,
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"%s, line %d: line too long or missing newline",
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SUAUTHFILE, lines));
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continue;
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}
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while (endline > 0 && (temp[endline - 1] == ' '
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|| temp[endline - 1] == '\t'
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|| temp[endline - 1] == '\n'))
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endline--;
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temp[endline] = '\0';
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posn = 0;
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while (temp[posn] == ' ' || temp[posn] == '\t')
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posn++;
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if (temp[posn] == '\n' || temp[posn] == '#'
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|| temp[posn] == '\0') {
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continue;
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}
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if (!(to_users = strtok (temp + posn, field))
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|| !(from_users = strtok ((char *) NULL, field))
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|| !(action = strtok ((char *) NULL, field))
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|| strtok ((char *) NULL, field)) {
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SYSLOG ((LOG_ERR,
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"%s, line %d. Bad number of fields.\n",
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SUAUTHFILE, lines));
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continue;
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}
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if (!applies (wanted_id, to_users))
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continue;
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if (!applies (actual_id, from_users))
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continue;
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if (!strcmp (action, "DENY")) {
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SYSLOG ((su_to_root ? LOG_WARN : LOG_NOTICE,
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"DENIED su from '%s' to '%s' (%s)\n",
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actual_id, wanted_id, SUAUTHFILE));
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fputs (_("Access to su to that account DENIED.\n"),
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stderr);
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fclose (authfile_fd);
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return DENY;
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} else if (!strcmp (action, "NOPASS")) {
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SYSLOG ((su_to_root ? LOG_NOTICE : LOG_INFO,
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"NO password asked for su from '%s' to '%s' (%s)\n",
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actual_id, wanted_id, SUAUTHFILE));
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fputs (_("Password authentication bypassed.\n"),stderr);
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fclose (authfile_fd);
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return NOPWORD;
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} else if (!strcmp (action, "OWNPASS")) {
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SYSLOG ((su_to_root ? LOG_NOTICE : LOG_INFO,
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"su from '%s' to '%s': asking for user's own password (%s)\n",
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actual_id, wanted_id, SUAUTHFILE));
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fputs (_("Please enter your OWN password as authentication.\n"),
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stderr);
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fclose (authfile_fd);
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return OWNPWORD;
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} else {
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SYSLOG ((LOG_ERR,
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"%s, line %d: unrecognized action!\n",
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SUAUTHFILE, lines));
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}
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}
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fclose (authfile_fd);
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return NOACTION;
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}
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static int applies (const char *single, char *list)
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{
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const char split[] = ", ";
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char *tok;
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int state = 0;
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for (tok = strtok (list, split); tok != NULL;
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tok = strtok (NULL, split)) {
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if (!strcmp (tok, "ALL")) {
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if (state != 0) {
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SYSLOG ((LOG_ERR,
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"%s, line %d: ALL in bad place\n",
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SUAUTHFILE, lines));
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return 0;
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}
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state = 1;
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} else if (!strcmp (tok, "EXCEPT")) {
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if (state != 1) {
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SYSLOG ((LOG_ERR,
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"%s, line %d: EXCEPT in bas place\n",
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SUAUTHFILE, lines));
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return 0;
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}
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state = 2;
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} else if (!strcmp (tok, "GROUP")) {
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if ((state != 0) && (state != 2)) {
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SYSLOG ((LOG_ERR,
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"%s, line %d: GROUP in bad place\n",
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SUAUTHFILE, lines));
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return 0;
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}
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state = (state == 0) ? 3 : 4;
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} else {
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switch (state) {
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case 0: /* No control words yet */
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if (!strcmp (tok, single))
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return 1;
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break;
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case 1: /* An all */
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SYSLOG ((LOG_ERR,
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"%s, line %d: expect another token after ALL\n",
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SUAUTHFILE, lines));
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return 0;
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case 2: /* All except */
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if (!strcmp (tok, single))
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return 0;
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break;
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case 3: /* Group */
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if (isgrp (single, tok))
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return 1;
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break;
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case 4: /* All except group */
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if (isgrp (single, tok))
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return 0;
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/* FALL THRU */
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}
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}
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}
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if ((state != 0) && (state != 3))
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return 1;
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return 0;
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}
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static int isgrp (const char *name, const char *group)
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{
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struct group *grp;
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grp = getgrnam (group); /* local, no need for xgetgrnam */
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if (!grp || !grp->gr_mem)
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return 0;
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return is_on_list (grp->gr_mem, name);
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}
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#endif /* SU_ACCESS */
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