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 __BEGIN_DECLS
50 
51 static __inline int
52 caph_limit_stream(int fd, int flags)
53 {
54 	cap_rights_t rights;
55 	unsigned long cmds[] = { TIOCGETA, TIOCGWINSZ, FIODTYPE };
56 
57 	cap_rights_init(&rights, CAP_EVENT, CAP_FCNTL, CAP_FSTAT,
58 	    CAP_IOCTL, CAP_SEEK);
59 
60 	if ((flags & CAPH_READ) != 0)
61 		cap_rights_set(&rights, CAP_READ);
62 	if ((flags & CAPH_WRITE) != 0)
63 		cap_rights_set(&rights, CAP_WRITE);
64 	if ((flags & CAPH_LOOKUP) != 0)
65 		cap_rights_set(&rights, CAP_LOOKUP);
66 
67 	if (cap_rights_limit(fd, &rights) < 0 && errno != ENOSYS) {
68 		if (errno == EBADF && (flags & CAPH_IGNORE_EBADF) != 0)
69 			return (0);
70 		return (-1);
71 	}
72 
73 	if (cap_ioctls_limit(fd, cmds, nitems(cmds)) < 0 && errno != ENOSYS)
74 		return (-1);
75 
76 	if (cap_fcntls_limit(fd, CAP_FCNTL_GETFL) < 0 && errno != ENOSYS)
77 		return (-1);
78 
79 	return (0);
80 }
81 
82 static __inline int
83 caph_limit_stdin(void)
84 {
85 
86 	return (caph_limit_stream(STDIN_FILENO, CAPH_READ));
87 }
88 
89 static __inline int
90 caph_limit_stderr(void)
91 {
92 
93 	return (caph_limit_stream(STDERR_FILENO, CAPH_WRITE));
94 }
95 
96 static __inline int
97 caph_limit_stdout(void)
98 {
99 
100 	return (caph_limit_stream(STDOUT_FILENO, CAPH_WRITE));
101 }
102 
103 static __inline int
104 caph_limit_stdio(void)
105 {
106 	const int iebadf = CAPH_IGNORE_EBADF;
107 
108 	if (caph_limit_stream(STDIN_FILENO, CAPH_READ | iebadf) == -1 ||
109 	    caph_limit_stream(STDOUT_FILENO, CAPH_WRITE | iebadf) == -1 ||
110 	    caph_limit_stream(STDERR_FILENO, CAPH_WRITE | iebadf) == -1)
111 		return (-1);
112 	return (0);
113 }
114 
115 static __inline void
116 caph_cache_tzdata(void)
117 {
118 
119 	tzset();
120 }
121 
122 static __inline void
123 caph_cache_catpages(void)
124 {
125 
126 	(void)catopen("libc", NL_CAT_LOCALE);
127 }
128 
129 static __inline int
130 caph_enter(void)
131 {
132 
133 	if (cap_enter() < 0 && errno != ENOSYS)
134 		return (-1);
135 
136 	return (0);
137 }
138 
139 static __inline int
140 caph_rights_limit(int fd, const cap_rights_t *rights)
141 {
142 
143 	if (cap_rights_limit(fd, rights) < 0 && errno != ENOSYS)
144 		return (-1);
145 
146 	return (0);
147 }
148 
149 static __inline int
150 caph_ioctls_limit(int fd, const unsigned long *cmds, size_t ncmds)
151 {
152 
153 	if (cap_ioctls_limit(fd, cmds, ncmds) < 0 && errno != ENOSYS)
154 		return (-1);
155 
156 	return (0);
157 }
158 
159 static __inline int
160 caph_fcntls_limit(int fd, uint32_t fcntlrights)
161 {
162 
163 	if (cap_fcntls_limit(fd, fcntlrights) < 0 && errno != ENOSYS)
164 		return (-1);
165 
166 	return (0);
167 }
168 
169 static __inline int
170 caph_enter_casper(void)
171 {
172 
173 	return (CASPER_SUPPORT == 0 ? 0 : caph_enter());
174 }
175 
176 __END_DECLS
177 
178 #endif /* _CAPSICUM_HELPERS_H_ */
179