1 /*
2  * Copyright (c) 2014-2016 Dmitry V. Levin <ldv@altlinux.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  * 3. The name of the author may not be used to endorse or promote products
14  *    derived from this software without specific prior written permission.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26  */
27 
28 #include "tests.h"
29 #include <errno.h>
30 #include <fcntl.h>
31 #include <stdlib.h>
32 #include <unistd.h>
33 
34 int
35 read_int_from_file(const char *const fname, int *const pvalue)
36 {
37 	const int fd = open(fname, O_RDONLY);
38 	if (fd < 0)
39 		return -1;
40 
41 	long lval;
42 	char buf[sizeof(lval) * 3];
43 	int n = read(fd, buf, sizeof(buf) - 1);
44 	int saved_errno = errno;
45 	close(fd);
46 
47 	if (n < 0) {
48 		errno = saved_errno;
49 		return -1;
50 	}
51 
52 	buf[n] = '\0';
53 	char *endptr = 0;
54 	errno = 0;
55 	lval = strtol(buf, &endptr, 10);
56 	if (!endptr || (*endptr && '\n' != *endptr)
57 #if INT_MAX < LONG_MAX
58 	    || lval > INT_MAX || lval < INT_MIN
59 #endif
60 	    || ERANGE == errno) {
61 		if (!errno)
62 			errno = EINVAL;
63 		return -1;
64 	}
65 
66 	*pvalue = (int) lval;
67 	return 0;
68 }
69 
70 static void
71 check_overflow_id(const int id, const char *overflowid)
72 {
73 	int n;
74 
75 	if (read_int_from_file(overflowid, &n)) {
76 		if (ENOENT == errno)
77 			return;
78 		perror_msg_and_fail("read_int_from_file: %s", overflowid);
79 	}
80 
81 	if (id == n)
82 		error_msg_and_skip("%d matches %s", id, overflowid);
83 }
84 
85 void
86 check_overflowuid(const int uid)
87 {
88 	check_overflow_id(uid, "/proc/sys/kernel/overflowuid");
89 }
90 
91 void
92 check_overflowgid(const int gid)
93 {
94 	check_overflow_id(gid, "/proc/sys/kernel/overflowgid");
95 }
96