You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 
 
 
 
 
 
shadow/src/login_nopam.c

341 lines
9.9 KiB

/* 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 */