login_fbtab.c revision 87233 
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
63__FBSDID("$FreeBSD: head/usr.bin/login/login_fbtab.c 87233 2001-12-02 20:54:57Z markm $");
64
65#include <sys/types.h>
66#include <sys/stat.h>
67#include <errno.h>
68#include <glob.h>
69#include <paths.h>
70#include <stdio.h>
71#include <string.h>
72#include <syslog.h>
73#include <unistd.h>
74
75#include "login.h"
76#include "pathnames.h"
77
78static void	login_protect	__P((const char *, char *, int, uid_t, gid_t));
79
80#define	WSPACE		" \t\n"
81
82/* login_fbtab - apply protections specified in /etc/fbtab or logindevperm */
83
84void
85login_fbtab(tty, uid, gid)
86char   *tty;
87uid_t   uid;
88gid_t   gid;
89{
90    FILE   *fp;
91    char    buf[BUFSIZ];
92    char   *devname;
93    char   *cp;
94    int     prot;
95    const char *table;
96
97    if ((fp = fopen(table = _PATH_FBTAB, "r")) == 0
98    && (fp = fopen(table = _PATH_LOGINDEVPERM, "r")) == 0)
99	return;
100
101    while (fgets(buf, sizeof(buf), fp)) {
102	if ((cp = strchr(buf, '#')))
103	    *cp = 0;				/* strip comment */
104	if ((cp = devname = strtok(buf, WSPACE)) == 0)
105	    continue;				/* empty or comment */
106	if (strncmp(devname, _PATH_DEV, sizeof _PATH_DEV - 1) != 0
107	       || (cp = strtok((char *) 0, WSPACE)) == 0
108	       || *cp != '0'
109	       || sscanf(cp, "%o", &prot) == 0
110	       || prot == 0
111	       || (prot & 0777) != prot
112	       || (cp = strtok((char *) 0, WSPACE)) == 0) {
113	    syslog(LOG_ERR, "%s: bad entry: %s", table, cp ? cp : "(null)");
114	    continue;
115	}
116	if (strcmp(devname + 5, tty) == 0) {
117	    for (cp = strtok(cp, ":"); cp; cp = strtok((char *) 0, ":")) {
118		login_protect(table, cp, prot, uid, gid);
119	    }
120	}
121    }
122    fclose(fp);
123}
124
125/* login_protect - protect one device entry */
126
127void
128login_protect(table, pattern, mask, uid, gid)
129const char *table;
130char *pattern;
131int mask;
132uid_t uid;
133gid_t gid;
134{
135    glob_t  gl;
136    char   *path;
137    int     i;
138
139    if (glob(pattern, GLOB_NOSORT, NULL, &gl) != 0)
140	return;
141    for (i = 0; i < gl.gl_pathc; i++) {
142	path = gl.gl_pathv[i];
143	/* clear flags of the device */
144	if (chflags(path, 0) && errno != ENOENT && errno != EOPNOTSUPP)
145	    syslog(LOG_ERR, "%s: chflags(%s): %m", table, path);
146	if (chmod(path, mask) && errno != ENOENT)
147	    syslog(LOG_ERR, "%s: chmod(%s): %m", table, path);
148	if (chown(path, uid, gid) && errno != ENOENT)
149	    syslog(LOG_ERR, "%s: chown(%s): %m", table, path);
150    }
151    globfree(&gl);
152}
153