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