xref: /freebsd/lib/libcapsicum/capsicum_helpers.h (revision 8657387683946d0c03e09fe77029edfe309eeb20)
1 /*-
2  * Copyright (c) 2016 Mariusz Zaborski <oshogbo@FreeBSD.org>
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  *
26  * $FreeBSD$
27  */
28 
29 #ifndef _CAPSICUM_HELPERS_H_
30 #define	_CAPSICUM_HELPERS_H_
31 
32 #include <sys/param.h>
33 #include <sys/capsicum.h>
34 #include <sys/ioctl.h>
35 
36 #include <errno.h>
37 #include <nl_types.h>
38 #include <termios.h>
39 #include <time.h>
40 #include <unistd.h>
41 
42 #define	CAPH_IGNORE_EBADF	0x0001
43 #define	CAPH_READ		0x0002
44 #define	CAPH_WRITE		0x0004
45 #define	CAPH_LOOKUP		0x0008
46 
47 static __inline int
48 caph_limit_stream(int fd, int flags)
49 {
50 	cap_rights_t rights;
51 	unsigned long cmds[] = { TIOCGETA, TIOCGWINSZ, FIODTYPE };
52 
53 	cap_rights_init(&rights, CAP_FCNTL, CAP_FSTAT, CAP_IOCTL);
54 
55 	if ((flags & CAPH_READ) != 0)
56 		cap_rights_set(&rights, CAP_READ);
57 	if ((flags & CAPH_WRITE) != 0)
58 		cap_rights_set(&rights, CAP_WRITE);
59 	if ((flags & CAPH_LOOKUP) != 0)
60 		cap_rights_set(&rights, CAP_LOOKUP);
61 
62 	if (cap_rights_limit(fd, &rights) < 0 && errno != ENOSYS) {
63 		if (errno == EBADF && (flags & CAPH_IGNORE_EBADF) != 0)
64 			return (0);
65 		return (-1);
66 	}
67 
68 	if (cap_ioctls_limit(fd, cmds, nitems(cmds)) < 0 && errno != ENOSYS)
69 		return (-1);
70 
71 	if (cap_fcntls_limit(fd, CAP_FCNTL_GETFL) < 0 && errno != ENOSYS)
72 		return (-1);
73 
74 	return (0);
75 }
76 
77 static __inline int
78 caph_limit_stdin(void)
79 {
80 
81 	return (caph_limit_stream(STDIN_FILENO, CAPH_READ));
82 }
83 
84 static __inline int
85 caph_limit_stderr(void)
86 {
87 
88 	return (caph_limit_stream(STDERR_FILENO, CAPH_WRITE));
89 }
90 
91 static __inline int
92 caph_limit_stdout(void)
93 {
94 
95 	return (caph_limit_stream(STDOUT_FILENO, CAPH_WRITE));
96 }
97 
98 static __inline int
99 caph_limit_stdio(void)
100 {
101 	const int iebadf = CAPH_IGNORE_EBADF;
102 
103 	if (caph_limit_stream(STDIN_FILENO, CAPH_READ | iebadf) == -1 ||
104 	    caph_limit_stream(STDOUT_FILENO, CAPH_WRITE | iebadf) == -1 ||
105 	    caph_limit_stream(STDERR_FILENO, CAPH_WRITE | iebadf) == -1)
106 		return (-1);
107 	return (0);
108 }
109 
110 static __inline void
111 caph_cache_tzdata(void)
112 {
113 
114 	tzset();
115 }
116 
117 static __inline void
118 caph_cache_catpages(void)
119 {
120 
121 	(void)catopen("libc", NL_CAT_LOCALE);
122 }
123 
124 #endif /* _CAPSICUM_HELPERS_H_ */
125