login_fbtab.c revision 33358 
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/types.h>
62#include <sys/stat.h>
63#include <stdio.h>
64#include <syslog.h>
65#include <string.h>
66#include <errno.h>
67#include <dirent.h>
68#include <unistd.h>
69#include "pathnames.h"
70
71void	login_protect	__P((char *, char *, int, uid_t, gid_t));
72void	login_fbtab	__P((char *tty, uid_t uid, gid_t gid));
73
74#define	WSPACE		" \t\n"
75
76/* login_fbtab - apply protections specified in /etc/fbtab or logindevperm */
77
78void
79login_fbtab(tty, uid, gid)
80char   *tty;
81uid_t   uid;
82gid_t   gid;
83{
84    FILE   *fp;
85    char    buf[BUFSIZ];
86    char   *devname;
87    char   *cp;
88    int     prot;
89    char *table;
90
91    if ((fp = fopen(table = _PATH_FBTAB, "r")) == 0
92    && (fp = fopen(table = _PATH_LOGINDEVPERM, "r")) == 0)
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)) == 0)
99	    continue;				/* empty or comment */
100	if (strncmp(devname, "/dev/", 5) != 0
101	       || (cp = strtok((char *) 0, WSPACE)) == 0
102	       || *cp != '0'
103	       || sscanf(cp, "%o", &prot) == 0
104	       || prot == 0
105	       || (prot & 0777) != prot
106	       || (cp = strtok((char *) 0, WSPACE)) == 0) {
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((char *) 0, ":")) {
112		login_protect(table, cp, prot, uid, gid);
113	    }
114	}
115    }
116    fclose(fp);
117}
118
119/* login_protect - protect one device entry */
120
121void
122login_protect(table, path, mask, uid, gid)
123char *table;
124char *path;
125int mask;
126uid_t uid;
127gid_t gid;
128{
129    char    buf[BUFSIZ];
130    int     pathlen = strlen(path);
131    struct dirent *ent;
132    DIR    *dir;
133
134    if (strcmp("/*", path + pathlen - 2) != 0) {
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    } else {
140	strcpy(buf, path);
141	buf[pathlen - 1] = 0;
142	if ((dir = opendir(buf)) == 0) {
143	    syslog(LOG_ERR, "%s: opendir(%s): %m", table, path);
144	} else {
145	    while ((ent = readdir(dir)) != 0) {
146		if (strcmp(ent->d_name, ".") != 0
147		    && strcmp(ent->d_name, "..") != 0) {
148		    strcpy(buf + pathlen - 1, ent->d_name);
149		    login_protect(table, buf, mask, uid, gid);
150		}
151	    }
152	    closedir(dir);
153	}
154    }
155}
156