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/************************************************************************
* NCSA HTTPd Server
* Software Development Group
* National Center for Supercomputing Applications
* University of Illinois at Urbana-Champaign
* 605 E. Springfield, Champaign, IL 61820
* httpd@ncsa.uiuc.edu
*
* Copyright (C) 1995, Board of Trustees of the University of Illinois
*
************************************************************************
*
* open_logfile.c,v 1.5 1995/11/03 21:57:23 blong Exp
*
************************************************************************
*
* open_logfile.c: Save me from myself safe logs openning to prevent security
* holes.
*
*/
#include "config.h"
#include "portability.h"
#include <stdio.h>
#ifndef NO_STDLIB_H
# include <stdlib.h>
#endif /* NO_STDLIB_H */
#ifndef NO_MALLOC_H
# ifdef NEED_SYS_MALLOC_H
# include <sys/malloc.h>
# else
# include <malloc.h>
# endif /* NEED_SYS_MALLOC_H */
#endif /* NO_MALLOC_H */
#include <sys/types.h>
#include <sys/stat.h>
#include <string.h>
#include <fcntl.h>
#include "constants.h"
#include "http_config.h"
#include "open_logfile.h"
#include "util.h"
/* Enough systems don't have this that we define it here if necessary
*/
#ifndef S_ISLNK
#define S_ISLNK(m) (((m)&(S_IFMT)) == (S_IFLNK))
#endif /* S_ISLNK */
struct mystat
{
struct stat real, link;
int rok, lok;
};
static
int
is_symbolic_link(struct mystat *x)
{
return x->lok == 0 && (S_ISLNK(x->link.st_mode));
}
static
int
group_write_allowed(struct mystat *x)
{
return x->rok == 0 && (S_IWGRP & x->real.st_mode);
}
static
int
other_write_allowed(struct mystat *x)
{
return x->rok == 0 && (S_IWOTH & x->real.st_mode);
}
static
int
inode_changed (struct mystat *before, struct mystat *after)
{
if (before->rok != 0) return 0;
if (before->lok != 0) return 0;
if (after->rok != 0) return 1;
if (after->lok != 0) return 1;
if (before->real.st_ino != after->real.st_ino) return 1;
if (before->link.st_ino != after->link.st_ino) return 1;
return 0;
}
static
int
running_as_root()
{
return geteuid() == 0 ;
}
/* this routine doesn't do what I need. It needs to return
* a name which can be used "as is" - now it only returns
* the name given on the ln -s command, which is a name relative
* to the link name itself
* For example, if "logs/b" is linked by
* cd logs
* ln -s b c
* ls -l
* lrwx------ c -> b
*
* then the link name returned for "logs/c" is "b" not "logs/b"
* I need to work harder to get the name right
*/
static
char *
symbolic_link_name (char * name)
{
static char linkname[1024];
int n;
n = readlink (name, linkname, sizeof(linkname) - 1);
if (n <= 0) return (char *)NULL;
linkname[n] = 0;
return linkname;
}
static
char *
parent_directory (char *name)
{
char *slash;
char *dir;
dir = strdup(name);
slash = strrchr(dir,'/');
if (slash)
{
*slash = 0;
}
else
{
free (dir);
dir = strdup (".");
}
return dir;
}
static
void
mystat(char *name, struct mystat *x)
{
x->rok = stat (name, &x->real);
x->lok = lstat (name, &x->link);
}
static
void
check_before (char *name, struct mystat *before)
{
char *dir;
if (!running_as_root()) return;
dir = parent_directory (name);
mystat (dir, before);
if (!log_directory_group_write_ok && group_write_allowed(before))
{
fprintf (stderr, "ERROR: log directory <%s> has 'group' write permission set\n", dir);
exit(1);
}
if (!log_directory_other_write_ok && other_write_allowed(before))
{
fprintf (stderr, "ERROR: log directory <%s> has 'other' write permission set\n", dir);
exit(1);
}
free (dir);
}
static
void
check_after (char *name, struct mystat *before, struct mystat *after)
{
char *dir;
if (!running_as_root()) return;
dir = parent_directory (name);
mystat (dir, after);
if(inode_changed (before, after))
{
fprintf (stderr, "WARNING: possible security breach\n");
fprintf (stderr, "Log directory <%s> has new inode number after opening logfile <%s>\n", dir, name);
fprintf (stderr, "This means that the log directory <%s> has been moved or removed and a new one put in it's place after the log file <%s> had been opened\n", dir, name);
exit(1);
}
free (dir);
}
FILE *
fopen_logfile (char *name, char *mode)
{
struct mystat before, after;
FILE *fd;
check_before (name, &before);
fd = fopen (name, mode);
if (fd == NULL) return fd;
check_after (name, &before, &after);
return fd;
}
int
open_logfile (char *name, int flags, mode_t mode)
{
struct mystat before, after;
int fd;
check_before (name, &before);
fd = open (name, flags, mode);
if (fd < 0) return fd;
check_after (name, &before, &after);
return fd;
}
These are the contents of the former NiCE NeXT User Group NeXTSTEP/OpenStep software archive, currently hosted by Netfuture.ch.