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