usr.bin/login/login_fbtab.c

   1 /************************************************************************
   2 * Copyright 1995 by Wietse Venema.  All rights reserved.
   3 *
   4 * This material was originally written and compiled by Wietse Venema at
   5 * Eindhoven University of Technology, The Netherlands, in 1990, 1991,
   6 * 1992, 1993, 1994 and 1995.
   7 *
   8 * Redistribution and use in source and binary forms are permitted
   9 * provided that this entire copyright notice is duplicated in all such
  10 * copies.
  11 *
  12 * This software is provided "as is" and without any expressed or implied
  13 * warranties, including, without limitation, the implied warranties of
  14 * merchantibility and fitness for any particular purpose.
  15 ************************************************************************/
  16 /* $FreeBSD: src/usr.bin/login/login_fbtab.c,v 1.18 2007/09/21 01:55:11 kevlo Exp $ */
  17 /* $DragonFly: src/usr.bin/login/login_fbtab.c,v 1.3 2003/10/04 20:36:48 hmp Exp $ */
  18 /*
  19     SYNOPSIS
  20         void login_fbtab(tty, uid, gid)
  21         char *tty;
  22         uid_t uid;
  23         gid_t gid;
  24
  25     DESCRIPTION
  26         This module implements device security as described in the
  27         SunOS 4.1.x fbtab(5) and SunOS 5.x logindevperm(4) manual
  28         pages. The program first looks for /etc/fbtab. If that file
  29         cannot be opened it attempts to process /etc/logindevperm.
  30         We expect entries with the folowing format:
  31
  32             Comments start with a # and extend to the end of the line.
  33
  34             Blank lines or lines with only a comment are ignored.
  35
  36             All other lines consist of three fields delimited by
  37             whitespace: a login device (/dev/console), an octal
  38             permission number (0600), and a ":"-delimited list of
  39             devices (/dev/kbd:/dev/mouse). All device names are
  40             absolute paths. A path that ends in "*" refers to all
  41             directory entries except "." and "..".
  42
  43             If the tty argument (relative path) matches a login device
  44             name (absolute path), the permissions of the devices in the
  45             ":"-delimited list are set as specified in the second
  46             field, and their ownership is changed to that of the uid
  47             and gid arguments.
  48
  49     DIAGNOSTICS
  50         Problems are reported via the syslog daemon with severity
  51         LOG_ERR.
  52
  53     BUGS
  54         This module uses strtok(3), which may cause conflicts with other
  55         uses of that same routine.
  56
  57     AUTHOR
  58         Wietse Venema (wietse@wzv.win.tue.nl)
  59         Eindhoven University of Technology
  60         The Netherlands
  61  */
  62
  63 #include <sys/types.h>
  64 #include <sys/stat.h>
  65 #include <errno.h>
  66 #include <glob.h>
  67 #include <paths.h>
  68 #include <stdio.h>
  69 #include <string.h>
  70 #include <syslog.h>
  71 #include <unistd.h>
  72
  73 #include "login.h"
  74 #include "pathnames.h"
  75
  76 static void     login_protect(const char *, char *, int, uid_t, gid_t);
  77
  78 #define WSPACE          " \t\n"
  79
  80 /* login_fbtab - apply protections specified in /etc/fbtab or logindevperm */
  81
  82 void
  83 login_fbtab(char *tty, uid_t uid, gid_t gid)
  84 {
  85     FILE   *fp;
  86     char    buf[BUFSIZ];
  87     char   *devname;
  88     char   *cp;
  89     int     prot;
  90     const char *table;
  91
  92     if ((fp = fopen(table = _PATH_FBTAB, "r")) == NULL
  93     && (fp = fopen(table = _PATH_LOGINDEVPERM, "r")) == NULL)
  94         return;
  95
  96     while (fgets(buf, sizeof(buf), fp)) {
  97         if ((cp = strchr(buf, '#')))
  98             *cp = 0;                            /* strip comment */
  99         if ((cp = devname = strtok(buf, WSPACE)) == 0)
 100             continue;                           /* empty or comment */
 101         if (strncmp(devname, _PATH_DEV, sizeof _PATH_DEV - 1) != 0
 102                || (cp = strtok(NULL, WSPACE)) == 0
 103                || *cp != '0'
 104                || sscanf(cp, "%o", &prot) == 0
 105                || prot == 0
 106                || (prot & 0777) != prot
 107                || (cp = strtok(NULL, WSPACE)) == 0) {
 108             syslog(LOG_ERR, "%s: bad entry: %s", table, cp ? cp : "(null)");
 109             continue;
 110         }
 111         if (strcmp(devname + 5, tty) == 0) {
 112             for (cp = strtok(cp, ":"); cp; cp = strtok(NULL, ":")) {
 113                 login_protect(table, cp, prot, uid, gid);
 114             }
 115         }
 116     }
 117     fclose(fp);
 118 }
 119
 120 /* login_protect - protect one device entry */
 121
 122 void
 123 login_protect(const char *table, char *pattern, int mask, uid_t uid, gid_t gid)
 124 {
 125     glob_t  gl;
 126     char   *path;
 127     unsigned int     i;
 128
 129     if (glob(pattern, GLOB_NOSORT, NULL, &gl) != 0)
 130         return;
 131     for (i = 0; i < gl.gl_pathc; i++) {
 132         path = gl.gl_pathv[i];
 133         /* clear flags of the device */
 134         if (chflags(path, 0) && errno != ENOENT && errno != EOPNOTSUPP)
 135             syslog(LOG_ERR, "%s: chflags(%s): %m", table, path);
 136         if (chmod(path, mask) && errno != ENOENT)
 137             syslog(LOG_ERR, "%s: chmod(%s): %m", table, path);
 138         if (chown(path, uid, gid) && errno != ENOENT)
 139             syslog(LOG_ERR, "%s: chown(%s): %m", table, path);
 140     }
 141     globfree(&gl);
 142 }