278 lines
8.7 KiB
C
278 lines
8.7 KiB
C
/************************************************************************
|
|
* Copyright 1995 by Wietse Venema. All rights reserved. Some individual
|
|
* files may be covered by other copyrights.
|
|
*
|
|
* 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, with or without
|
|
* modification, 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.
|
|
************************************************************************/
|
|
/*
|
|
* 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 "login_locl.h"
|
|
|
|
RCSID("$Id: login_access.c,v 1.2 2001/06/04 14:09:45 assar Exp $");
|
|
|
|
/* Delimiters for fields and for lists of users, ttys or hosts. */
|
|
|
|
static char fs[] = ":"; /* field separator */
|
|
static char sep[] = ", \t"; /* list-element separator */
|
|
|
|
/* Constants to be used in assignments only, not in comparisons... */
|
|
|
|
#define YES 1
|
|
#define NO 0
|
|
|
|
/*
|
|
* A structure to bundle up all login-related information to keep the
|
|
* functional interfaces as generic as possible.
|
|
*/
|
|
struct login_info {
|
|
struct passwd *user;
|
|
char *from;
|
|
};
|
|
|
|
static int list_match(char *list, struct login_info *item,
|
|
int (*match_fn)(char *, struct login_info *));
|
|
static int user_match(char *tok, struct login_info *item);
|
|
static int from_match(char *tok, struct login_info *item);
|
|
static int string_match(char *tok, char *string);
|
|
|
|
/* login_access - match username/group and host/tty with access control file */
|
|
|
|
int login_access(struct passwd *user, char *from)
|
|
{
|
|
struct login_info item;
|
|
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 */
|
|
int match = NO;
|
|
int end;
|
|
int lineno = 0; /* for diagnostics */
|
|
char *foo;
|
|
|
|
/*
|
|
* Bundle up the arguments to avoid unnecessary clumsiness lateron.
|
|
*/
|
|
item.user = user;
|
|
item.from = from;
|
|
|
|
/*
|
|
* 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.
|
|
*/
|
|
|
|
if ((fp = fopen(_PATH_LOGACCESS, "r")) != 0) {
|
|
while (!match && fgets(line, sizeof(line), fp)) {
|
|
lineno++;
|
|
if (line[end = strlen(line) - 1] != '\n') {
|
|
syslog(LOG_ERR, "%s: line %d: missing newline or line too long",
|
|
_PATH_LOGACCESS, lineno);
|
|
continue;
|
|
}
|
|
if (line[0] == '#')
|
|
continue; /* comment line */
|
|
while (end > 0 && isspace((unsigned char)line[end - 1]))
|
|
end--;
|
|
line[end] = 0; /* strip trailing whitespace */
|
|
if (line[0] == 0) /* skip blank lines */
|
|
continue;
|
|
foo = NULL;
|
|
if (!(perm = strtok_r(line, fs, &foo))
|
|
|| !(users = strtok_r(NULL, fs, &foo))
|
|
|| !(froms = strtok_r(NULL, fs, &foo))
|
|
|| strtok_r(NULL, fs, &foo)) {
|
|
syslog(LOG_ERR, "%s: line %d: bad field count",
|
|
_PATH_LOGACCESS,
|
|
lineno);
|
|
continue;
|
|
}
|
|
if (perm[0] != '+' && perm[0] != '-') {
|
|
syslog(LOG_ERR, "%s: line %d: bad first field",
|
|
_PATH_LOGACCESS,
|
|
lineno);
|
|
continue;
|
|
}
|
|
match = (list_match(froms, &item, from_match)
|
|
&& list_match(users, &item, user_match));
|
|
}
|
|
fclose(fp);
|
|
} else if (errno != ENOENT) {
|
|
syslog(LOG_ERR, "cannot open %s: %m", _PATH_LOGACCESS);
|
|
}
|
|
return (match == 0 || (line[0] == '+'));
|
|
}
|
|
|
|
/* list_match - match an item against a list of tokens with exceptions */
|
|
|
|
static int
|
|
list_match(char *list,
|
|
struct login_info *item,
|
|
int (*match_fn)(char *, struct login_info *))
|
|
{
|
|
char *tok;
|
|
int match = NO;
|
|
char *foo = NULL;
|
|
|
|
/*
|
|
* 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_r(list, sep, &foo);
|
|
tok != NULL;
|
|
tok = strtok_r(NULL, sep, &foo)) {
|
|
if (strcasecmp(tok, "EXCEPT") == 0) /* EXCEPT: give up */
|
|
break;
|
|
if ((match = (*match_fn) (tok, item)) != 0) /* YES */
|
|
break;
|
|
}
|
|
/* Process exceptions to matches. */
|
|
|
|
if (match != NO) {
|
|
while ((tok = strtok_r(NULL, sep, &foo)) && strcasecmp(tok, "EXCEPT"))
|
|
/* VOID */ ;
|
|
if (tok == 0 || list_match(NULL, item, match_fn) == NO)
|
|
return (match);
|
|
}
|
|
return (NO);
|
|
}
|
|
|
|
/* 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);
|
|
}
|
|
|
|
/* netgroup_match - match group against machine or user */
|
|
|
|
static int netgroup_match(char *group, char *machine, char *user)
|
|
{
|
|
#ifdef HAVE_YP_GET_DEFAULT_DOMAIN
|
|
static char *mydomain = 0;
|
|
|
|
if (mydomain == 0)
|
|
yp_get_default_domain(&mydomain);
|
|
return (innetgr(group, machine, user, mydomain));
|
|
#else
|
|
syslog(LOG_ERR, "NIS netgroup support not configured");
|
|
return 0;
|
|
#endif
|
|
}
|
|
|
|
/* user_match - match a username against one token */
|
|
|
|
static int user_match(char *tok, struct login_info *item)
|
|
{
|
|
char *string = item->user->pw_name;
|
|
struct login_info fake_item;
|
|
struct group *group;
|
|
int i;
|
|
char *at;
|
|
|
|
/*
|
|
* If a token has the magic value "ALL" the match always succeeds.
|
|
* Otherwise, return YES if the token fully matches the username, if the
|
|
* token is a group that contains the username, or if the token is the
|
|
* name of the user's primary group.
|
|
*/
|
|
|
|
if ((at = strchr(tok + 1, '@')) != 0) { /* split user@host pattern */
|
|
*at = 0;
|
|
fake_item.from = myhostname();
|
|
return (user_match(tok, item) && from_match(at + 1, &fake_item));
|
|
} else if (tok[0] == '@') { /* netgroup */
|
|
return (netgroup_match(tok + 1, (char *) 0, string));
|
|
} else if (string_match(tok, string)) { /* ALL or exact match */
|
|
return (YES);
|
|
} else if ((group = getgrnam(tok)) != 0) { /* try group membership */
|
|
if (item->user->pw_gid == group->gr_gid)
|
|
return (YES);
|
|
for (i = 0; group->gr_mem[i]; i++)
|
|
if (strcasecmp(string, group->gr_mem[i]) == 0)
|
|
return (YES);
|
|
}
|
|
return (NO);
|
|
}
|
|
|
|
/* from_match - match a host or tty against a list of tokens */
|
|
|
|
static int from_match(char *tok, struct login_info *item)
|
|
{
|
|
char *string = item->from;
|
|
int tok_len;
|
|
int str_len;
|
|
|
|
/*
|
|
* If a token has the magic value "ALL" the match always succeeds. Return
|
|
* YES if the token fully matches the string. If the token is a domain
|
|
* name, return YES if it matches the last fields of the string. If the
|
|
* token has the magic value "LOCAL", return YES if the string does not
|
|
* contain a "." character. If the token is a network number, return YES
|
|
* if it matches the head of the string.
|
|
*/
|
|
|
|
if (tok[0] == '@') { /* netgroup */
|
|
return (netgroup_match(tok + 1, string, (char *) 0));
|
|
} else if (string_match(tok, string)) { /* ALL or exact match */
|
|
return (YES);
|
|
} else if (tok[0] == '.') { /* domain: match last fields */
|
|
if ((str_len = strlen(string)) > (tok_len = strlen(tok))
|
|
&& strcasecmp(tok, string + str_len - tok_len) == 0)
|
|
return (YES);
|
|
} else if (strcasecmp(tok, "LOCAL") == 0) { /* local: no dots */
|
|
if (strchr(string, '.') == 0)
|
|
return (YES);
|
|
} else if (tok[(tok_len = strlen(tok)) - 1] == '.' /* network */
|
|
&& strncmp(tok, string, tok_len) == 0) {
|
|
return (YES);
|
|
}
|
|
return (NO);
|
|
}
|
|
|
|
/* string_match - match a string against one token */
|
|
|
|
static int string_match(char *tok, char *string)
|
|
{
|
|
|
|
/*
|
|
* If the token has the magic value "ALL" the match always succeeds.
|
|
* Otherwise, return YES if the token fully matches the string.
|
|
*/
|
|
|
|
if (strcasecmp(tok, "ALL") == 0) { /* all: always matches */
|
|
return (YES);
|
|
} else if (strcasecmp(tok, string) == 0) { /* try exact match */
|
|
return (YES);
|
|
}
|
|
return (NO);
|
|
}
|