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