login_fbtab.c revision 169342
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/* 17 SYNOPSIS 18 void login_fbtab(tty, uid, gid) 19 char *tty; 20 uid_t uid; 21 gid_t gid; 22 23 DESCRIPTION 24 This module implements device security as described in the 25 SunOS 4.1.x fbtab(5) and SunOS 5.x logindevperm(4) manual 26 pages. The program first looks for /etc/fbtab. If that file 27 cannot be opened it attempts to process /etc/logindevperm. 28 We expect entries with the folowing format: 29 30 Comments start with a # and extend to the end of the line. 31 32 Blank lines or lines with only a comment are ignored. 33 34 All other lines consist of three fields delimited by 35 whitespace: a login device (/dev/console), an octal 36 permission number (0600), and a ":"-delimited list of 37 devices (/dev/kbd:/dev/mouse). All device names are 38 absolute paths. A path that ends in "*" refers to all 39 directory entries except "." and "..". 40 41 If the tty argument (relative path) matches a login device 42 name (absolute path), the permissions of the devices in the 43 ":"-delimited list are set as specified in the second 44 field, and their ownership is changed to that of the uid 45 and gid arguments. 46 47 DIAGNOSTICS 48 Problems are reported via the syslog daemon with severity 49 LOG_ERR. 50 51 BUGS 52 This module uses strtok(3), which may cause conflicts with other 53 uses of that same routine. 54 55 AUTHOR 56 Wietse Venema (wietse@wzv.win.tue.nl) 57 Eindhoven University of Technology 58 The Netherlands 59 */ 60 61#include <sys/cdefs.h> 62__FBSDID("$FreeBSD: head/usr.bin/login/login_fbtab.c 169342 2007-05-07 11:01:36Z dwmalone $"); 63 64#include <sys/types.h> 65#include <sys/stat.h> 66#include <errno.h> 67#include <glob.h> 68#include <paths.h> 69#include <stdio.h> 70#include <string.h> 71#include <syslog.h> 72#include <unistd.h> 73 74#include "login.h" 75#include "pathnames.h" 76 77static void login_protect(const char *, char *, int, uid_t, gid_t); 78 79#define WSPACE " \t\n" 80 81/* login_fbtab - apply protections specified in /etc/fbtab or logindevperm */ 82 83void 84login_fbtab(tty, uid, gid) 85char *tty; 86uid_t uid; 87gid_t gid; 88{ 89 FILE *fp; 90 char buf[BUFSIZ]; 91 char *devname; 92 char *cp; 93 int prot; 94 const char *table; 95 96 if ((fp = fopen(table = _PATH_FBTAB, "r")) == 0 97 && (fp = fopen(table = _PATH_LOGINDEVPERM, "r")) == 0) 98 return; 99 100 while (fgets(buf, sizeof(buf), fp)) { 101 if ((cp = strchr(buf, '#'))) 102 *cp = 0; /* strip comment */ 103 if ((cp = devname = strtok(buf, WSPACE)) == 0) 104 continue; /* empty or comment */ 105 if (strncmp(devname, _PATH_DEV, sizeof _PATH_DEV - 1) != 0 106 || (cp = strtok((char *) 0, WSPACE)) == 0 107 || *cp != '0' 108 || sscanf(cp, "%o", &prot) == 0 109 || prot == 0 110 || (prot & 0777) != prot 111 || (cp = strtok((char *) 0, WSPACE)) == 0) { 112 syslog(LOG_ERR, "%s: bad entry: %s", table, cp ? cp : "(null)"); 113 continue; 114 } 115 if (strcmp(devname + 5, tty) == 0) { 116 for (cp = strtok(cp, ":"); cp; cp = strtok((char *) 0, ":")) { 117 login_protect(table, cp, prot, uid, gid); 118 } 119 } 120 } 121 fclose(fp); 122} 123 124/* login_protect - protect one device entry */ 125 126void 127login_protect(table, pattern, mask, uid, gid) 128const char *table; 129char *pattern; 130int mask; 131uid_t uid; 132gid_t gid; 133{ 134 glob_t gl; 135 char *path; 136 unsigned int i; 137 138 if (glob(pattern, GLOB_NOSORT, NULL, &gl) != 0) 139 return; 140 for (i = 0; i < gl.gl_pathc; i++) { 141 path = gl.gl_pathv[i]; 142 /* clear flags of the device */ 143 if (chflags(path, 0) && errno != ENOENT && errno != EOPNOTSUPP) 144 syslog(LOG_ERR, "%s: chflags(%s): %m", table, path); 145 if (chmod(path, mask) && errno != ENOENT) 146 syslog(LOG_ERR, "%s: chmod(%s): %m", table, path); 147 if (chown(path, uid, gid) && errno != ENOENT) 148 syslog(LOG_ERR, "%s: chown(%s): %m", table, path); 149 } 150 globfree(&gl); 151} 152