xref: /freebsd/lib/libcapsicum/capsicum_helpers.h (revision 4f52dfbb8d6c4d446500c5b097e3806ec219fbd4)
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 #include <libcasper.h>
43 
44 #define	CAPH_IGNORE_EBADF	0x0001
45 #define	CAPH_READ		0x0002
46 #define	CAPH_WRITE		0x0004
47 #define	CAPH_LOOKUP		0x0008
48 
49 static __inline int
50 caph_limit_stream(int fd, int flags)
51 {
52 	cap_rights_t rights;
53 	unsigned long cmds[] = { TIOCGETA, TIOCGWINSZ, FIODTYPE };
54 
55 	cap_rights_init(&rights, CAP_EVENT, CAP_FCNTL, CAP_FSTAT,
56 	    CAP_IOCTL, CAP_SEEK);
57 
58 	if ((flags & CAPH_READ) != 0)
59 		cap_rights_set(&rights, CAP_READ);
60 	if ((flags & CAPH_WRITE) != 0)
61 		cap_rights_set(&rights, CAP_WRITE);
62 	if ((flags & CAPH_LOOKUP) != 0)
63 		cap_rights_set(&rights, CAP_LOOKUP);
64 
65 	if (cap_rights_limit(fd, &rights) < 0 && errno != ENOSYS) {
66 		if (errno == EBADF && (flags & CAPH_IGNORE_EBADF) != 0)
67 			return (0);
68 		return (-1);
69 	}
70 
71 	if (cap_ioctls_limit(fd, cmds, nitems(cmds)) < 0 && errno != ENOSYS)
72 		return (-1);
73 
74 	if (cap_fcntls_limit(fd, CAP_FCNTL_GETFL) < 0 && errno != ENOSYS)
75 		return (-1);
76 
77 	return (0);
78 }
79 
80 static __inline int
81 caph_limit_stdin(void)
82 {
83 
84 	return (caph_limit_stream(STDIN_FILENO, CAPH_READ));
85 }
86 
87 static __inline int
88 caph_limit_stderr(void)
89 {
90 
91 	return (caph_limit_stream(STDERR_FILENO, CAPH_WRITE));
92 }
93 
94 static __inline int
95 caph_limit_stdout(void)
96 {
97 
98 	return (caph_limit_stream(STDOUT_FILENO, CAPH_WRITE));
99 }
100 
101 static __inline int
102 caph_limit_stdio(void)
103 {
104 	const int iebadf = CAPH_IGNORE_EBADF;
105 
106 	if (caph_limit_stream(STDIN_FILENO, CAPH_READ | iebadf) == -1 ||
107 	    caph_limit_stream(STDOUT_FILENO, CAPH_WRITE | iebadf) == -1 ||
108 	    caph_limit_stream(STDERR_FILENO, CAPH_WRITE | iebadf) == -1)
109 		return (-1);
110 	return (0);
111 }
112 
113 static __inline void
114 caph_cache_tzdata(void)
115 {
116 
117 	tzset();
118 }
119 
120 static __inline void
121 caph_cache_catpages(void)
122 {
123 
124 	(void)catopen("libc", NL_CAT_LOCALE);
125 }
126 
127 static __inline int
128 caph_enter(void)
129 {
130 
131 	if (cap_enter() < 0 && errno != ENOSYS)
132 		return (-1);
133 
134 	return (0);
135 }
136 
137 
138 static __inline int
139 caph_enter_casper(void)
140 {
141 
142 	return (CASPER_SUPPORT == 0 ? 0 : caph_enter());
143 }
144 
145 #endif /* _CAPSICUM_HELPERS_H_ */
146