d5d1932370
It is a user, not an user. Signed-off-by: Samanta Navarro <ferivoz@riseup.net>
350 lines
10 KiB
C
350 lines
10 KiB
C
/* Taken from logdaemon-5.0, only minimal changes. --marekm */
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/*
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* SPDX-FileCopyrightText: 1990 - 1995, Wietse Venema.
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*
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* SPDX-License-Identifier: Unlicense
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*/
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/************************************************************************
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* Copyright 1995 by Wietse Venema. All rights reserved. Individual files
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* may be covered by other copyrights (as noted in the file itself.)
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*
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* This material was originally written and compiled by Wietse Venema at
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* Eindhoven University of Technology, The Netherlands, in 1990, 1991,
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* 1992, 1993, 1994 and 1995.
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*
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* Redistribution and use in source and binary forms are permitted
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* provided that this entire copyright notice is duplicated in all such
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* copies.
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*
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* This software is provided "as is" and without any expressed or implied
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* warranties, including, without limitation, the implied warranties of
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* merchantibility and fitness for any particular purpose.
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************************************************************************/
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#ifdef HAVE_CONFIG_H
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#include <config.h>
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#endif
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#ifndef USE_PAM
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#ident "$Id$"
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#include "prototypes.h"
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/*
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* This module implements a simple but effective form of login access
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* control based on login names and on host (or domain) names, internet
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* addresses (or network numbers), or on terminal line names in case of
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* non-networked logins. Diagnostics are reported through syslog(3).
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*
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* Author: Wietse Venema, Eindhoven University of Technology, The Netherlands.
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*/
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#include <sys/types.h>
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#include <stddef.h>
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#include <stdio.h>
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#include <syslog.h>
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#include <ctype.h>
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#include <netdb.h>
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#include <grp.h>
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#ifdef PRIMARY_GROUP_MATCH
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#include <pwd.h>
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#endif
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#include <errno.h>
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#include <string.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <sys/socket.h>
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#include <netinet/in.h>
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#include <arpa/inet.h> /* for inet_ntoa() */
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#if !defined(MAXHOSTNAMELEN) || (MAXHOSTNAMELEN < 64)
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#undef MAXHOSTNAMELEN
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#define MAXHOSTNAMELEN 256
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#endif
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/* Path name of the access control file. */
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#ifndef TABLE
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#define TABLE "/etc/login.access"
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#endif
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/* Delimiters for fields and for lists of users, ttys or hosts. */
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static char fs[] = ":"; /* field separator */
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static char sep[] = ", \t"; /* list-element separator */
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static bool list_match (char *list, const char *item, bool (*match_fn) (const char *, const char *));
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static bool user_match (const char *tok, const char *string);
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static bool from_match (const char *tok, const char *string);
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static bool string_match (const char *tok, const char *string);
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static const char *resolve_hostname (const char *string);
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/* login_access - match username/group and host/tty with access control file */
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int login_access (const char *user, const char *from)
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{
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FILE *fp;
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char line[BUFSIZ];
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char *perm; /* becomes permission field */
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char *users; /* becomes list of login names */
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char *froms; /* becomes list of terminals or hosts */
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bool match = false;
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/*
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* Process the table one line at a time and stop at the first match.
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* Blank lines and lines that begin with a '#' character are ignored.
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* Non-comment lines are broken at the ':' character. All fields are
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* mandatory. The first field should be a "+" or "-" character. A
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* non-existing table means no access control.
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*/
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fp = fopen (TABLE, "r");
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if (NULL != fp) {
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int lineno = 0; /* for diagnostics */
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while ( !match
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&& (fgets (line, sizeof (line), fp) == line)) {
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ptrdiff_t end;
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lineno++;
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end = strlen (line) - 1;
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if (line[0] == '\0' || line[end] != '\n') {
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SYSLOG ((LOG_ERR,
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"%s: line %d: missing newline or line too long",
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TABLE, lineno));
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continue;
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}
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if (line[0] == '#') {
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continue; /* comment line */
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}
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while (end > 0 && isspace (line[end - 1])) {
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end--;
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}
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line[end] = '\0'; /* strip trailing whitespace */
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if (line[0] == '\0') { /* skip blank lines */
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continue;
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}
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if ( ((perm = strtok (line, fs)) == NULL)
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|| ((users = strtok (NULL, fs)) == NULL)
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|| ((froms = strtok (NULL, fs)) == NULL)
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|| (strtok (NULL, fs) != NULL)) {
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SYSLOG ((LOG_ERR,
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"%s: line %d: bad field count",
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TABLE, lineno));
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continue;
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}
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if (perm[0] != '+' && perm[0] != '-') {
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SYSLOG ((LOG_ERR,
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"%s: line %d: bad first field",
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TABLE, lineno));
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continue;
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}
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match = ( list_match (froms, from, from_match)
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&& list_match (users, user, user_match));
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}
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(void) fclose (fp);
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} else if (errno != ENOENT) {
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int err = errno;
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SYSLOG ((LOG_ERR, "cannot open %s: %s", TABLE, strerror (err)));
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}
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return (!match || (line[0] == '+'))?1:0;
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}
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/* list_match - match an item against a list of tokens with exceptions */
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static bool list_match (char *list, const char *item, bool (*match_fn) (const char *, const char*))
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{
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char *tok;
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bool match = false;
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/*
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* Process tokens one at a time. We have exhausted all possible matches
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* when we reach an "EXCEPT" token or the end of the list. If we do find
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* a match, look for an "EXCEPT" list and recurse to determine whether
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* the match is affected by any exceptions.
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*/
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for (tok = strtok (list, sep); tok != NULL; tok = strtok (NULL, sep)) {
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if (strcasecmp (tok, "EXCEPT") == 0) { /* EXCEPT: give up */
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break;
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}
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match = (*match_fn) (tok, item);
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if (match) {
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break;
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}
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}
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/* Process exceptions to matches. */
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if (match) {
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while ( ((tok = strtok (NULL, sep)) != NULL)
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&& (strcasecmp (tok, "EXCEPT") != 0))
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/* VOID */ ;
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if (tok == 0 || !list_match (NULL, item, match_fn)) {
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return (match);
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}
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}
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return false;
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}
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/* myhostname - figure out local machine name */
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static char *myhostname (void)
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{
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static char name[MAXHOSTNAMELEN + 1] = "";
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if (name[0] == '\0') {
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gethostname (name, sizeof (name));
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name[MAXHOSTNAMELEN] = '\0';
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}
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return (name);
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}
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#if HAVE_INNETGR
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/* netgroup_match - match group against machine or user */
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static bool
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netgroup_match (const char *group, const char *machine, const char *user)
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{
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static char *mydomain = NULL;
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if (mydomain == NULL) {
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static char domain[MAXHOSTNAMELEN + 1];
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getdomainname (domain, MAXHOSTNAMELEN);
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mydomain = domain;
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}
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return (innetgr (group, machine, user, mydomain) != 0);
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}
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#endif
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/* user_match - match a username against one token */
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static bool user_match (const char *tok, const char *string)
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{
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struct group *group;
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#ifdef PRIMARY_GROUP_MATCH
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struct passwd *userinf;
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#endif
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char *at;
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/*
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* If a token has the magic value "ALL" the match always succeeds.
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* Otherwise, return true if the token fully matches the username, or if
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* the token is a group that contains the username.
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*/
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at = strchr (tok + 1, '@');
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if (NULL != at) { /* split user@host pattern */
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*at = '\0';
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return ( user_match (tok, string)
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&& from_match (at + 1, myhostname ()));
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#if HAVE_INNETGR
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} else if (tok[0] == '@') { /* netgroup */
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return (netgroup_match (tok + 1, NULL, string));
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#endif
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} else if (string_match (tok, string)) { /* ALL or exact match */
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return true;
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/* local, no need for xgetgrnam */
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} else if ((group = getgrnam (tok)) != NULL) { /* try group membership */
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int i;
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for (i = 0; NULL != group->gr_mem[i]; i++) {
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if (strcasecmp (string, group->gr_mem[i]) == 0) {
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return true;
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}
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}
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#ifdef PRIMARY_GROUP_MATCH
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/*
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* If the string is a user whose initial GID matches the token,
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* accept it. May avoid excessively long lines in /etc/group.
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* Radu-Adrian Feurdean <raf@licj.soroscj.ro>
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*
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* XXX - disabled by default for now. Need to verify that
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* getpwnam() doesn't have some nasty side effects. --marekm
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*/
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/* local, no need for xgetpwnam */
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userinf = getpwnam (string);
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if (NULL != userinf) {
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if (userinf->pw_gid == group->gr_gid) {
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return true;
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}
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}
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#endif
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}
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return false;
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}
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static const char *resolve_hostname (const char *string)
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{
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int gai_err;
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char *addr_str;
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struct addrinfo *addrs;
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static char host[MAXHOSTNAMELEN];
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gai_err = getaddrinfo(string, NULL, NULL, &addrs);
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if (gai_err != 0) {
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SYSLOG ((LOG_ERR, "getaddrinfo(%s): %s", string, gai_strerror(gai_err)));
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return string;
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}
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addr_str = host;
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gai_err = getnameinfo(addrs[0].ai_addr, addrs[0].ai_addrlen,
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host, NITEMS(host), NULL, 0, NI_NUMERICHOST);
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if (gai_err != 0) {
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SYSLOG ((LOG_ERR, "getnameinfo(%s): %s", string, gai_strerror(gai_err)));
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addr_str = string;
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}
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freeaddrinfo(addrs);
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return addr_str;
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}
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/* from_match - match a host or tty against a list of tokens */
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static bool from_match (const char *tok, const char *string)
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{
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size_t tok_len;
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/*
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* If a token has the magic value "ALL" the match always succeeds. Return
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* true if the token fully matches the string. If the token is a domain
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* name, return true if it matches the last fields of the string. If the
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* token has the magic value "LOCAL", return true if the string does not
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* contain a "." character. If the token is a network number, return true
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* if it matches the head of the string.
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*/
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#if HAVE_INNETGR
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if (tok[0] == '@') { /* netgroup */
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return (netgroup_match (tok + 1, string, NULL));
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} else
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#endif
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if (string_match (tok, string)) { /* ALL or exact match */
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return true;
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} else if (tok[0] == '.') { /* domain: match last fields */
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size_t str_len;
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str_len = strlen (string);
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tok_len = strlen (tok);
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if ( (str_len > tok_len)
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&& (strcasecmp (tok, string + str_len - tok_len) == 0)) {
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return true;
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}
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} else if (strcasecmp (tok, "LOCAL") == 0) { /* local: no dots */
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if (strchr (string, '.') == NULL) {
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return true;
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}
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} else if ( (tok[0] != '\0' && tok[(tok_len = strlen (tok)) - 1] == '.') /* network */
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&& (strncmp (tok, resolve_hostname (string), tok_len) == 0)) {
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return true;
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}
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return false;
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}
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/* string_match - match a string against one token */
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static bool string_match (const char *tok, const char *string)
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{
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/*
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* If the token has the magic value "ALL" the match always succeeds.
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* Otherwise, return true if the token fully matches the string.
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*/
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if (strcasecmp (tok, "ALL") == 0) { /* all: always matches */
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return true;
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} else if (strcasecmp (tok, string) == 0) { /* try exact match */
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return true;
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}
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return false;
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}
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#else /* !USE_PAM */
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extern int ISO_C_forbids_an_empty_translation_unit;
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#endif /* !USE_PAM */
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