1 /*
2  * Check decoding of modify_ldt syscall.
3  *
4  * Copyright (c) 2018 The strace developers.
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. The name of the author may not be used to endorse or promote products
16  *    derived from this software without specific prior written permission.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28  */
29 
30 #include "tests.h"
31 
32 #include <asm/unistd.h>
33 
34 #if defined __NR_modify_ldt && defined HAVE_STRUCT_USER_DESC
35 
36 # include <errno.h>
37 # include <stdio.h>
38 # include <unistd.h>
39 
40 # include "print_user_desc.c"
41 
42 void
43 printrc(long rc)
44 {
45 #ifdef __x86_64__
46 	int err = -rc;
47 
48 	/* Thanks, long return type of syscall(2) */
49 	printf("%lld", zero_extend_signed_to_ull(rc));
50 
51 	if (err > 0 && err < 0x1000) {
52 		errno = err;
53 		printf(" %s (%m)", errno2name());
54 	}
55 #else
56 	printf("%s", sprintrc(rc));
57 #endif
58 
59 	puts("");
60 }
61 
62 int
63 main(void)
64 {
65 	static const kernel_ulong_t bogus_func =
66 		(kernel_ulong_t) 0xbadc0dedda7a1057ULL;
67 	static const kernel_ulong_t bogus_bytecount =
68 		(kernel_ulong_t) 0xdeadfacefa57beefULL;
69 
70 	struct user_desc *us = tail_alloc(sizeof(*us));
71 	unsigned int *bogus_int = tail_alloc(sizeof(*bogus_int));
72 	long rc;
73 
74 	fill_memory(us, sizeof(*us));
75 
76 	rc = syscall(__NR_modify_ldt, 0, 0, 0);
77 	printf("modify_ldt(0, NULL, 0) = ");
78 	printrc(rc);
79 
80 	rc = syscall(__NR_modify_ldt, bogus_func, (kernel_long_t) -1,
81 		     bogus_bytecount);
82 	printf("modify_ldt(%d, %#llx, %llu) = ",
83 	       (int) bogus_func,
84 	       zero_extend_signed_to_ull((kernel_long_t) -1),
85 	       (unsigned long long) bogus_bytecount);
86 	printrc(rc);
87 
88 	rc = syscall(__NR_modify_ldt, bogus_func, us + 1, 0);
89 	printf("modify_ldt(%d, %p, 0) = ", (int) bogus_func, us + 1);
90 	printrc(rc);
91 
92 	rc = syscall(__NR_modify_ldt, bogus_func, us, 42);
93 	printf("modify_ldt(%d, %p, 42) = ", (int) bogus_func, us);
94 	printrc(rc);
95 
96 	rc = syscall(__NR_modify_ldt, bogus_func, us + 1, sizeof(*us));
97 	printf("modify_ldt(%d, %p, %zu) = ",
98 	       (int) bogus_func, us + 1, sizeof(*us));
99 	printrc(rc);
100 
101 	/*
102 	 * print_user_desc handles entry_number field in a special way for
103 	 * get_thread_area syscall, so let's also check here that we don't
104 	 * retrieve it accidentally.
105 	 */
106 	rc = syscall(__NR_modify_ldt, bogus_func, bogus_int, sizeof(*us));
107 	printf("modify_ldt(%d, %p, %zu) = ",
108 	       (int) bogus_func, bogus_int, sizeof(*us));
109 	printrc(rc);
110 
111 	rc = syscall(__NR_modify_ldt, bogus_func, us, sizeof(*us));
112 	printf("modify_ldt(%d, ", (int) bogus_func);
113 	print_user_desc(us, NULL);
114 	printf(", %zu) = ", sizeof(*us));
115 	printrc(rc);
116 
117 	fill_memory_ex(us, sizeof(*us), 0x55, 80);
118 	us->entry_number = -1;
119 	us->base_addr = 0;
120 	us->limit = 0;
121 
122 	rc = syscall(__NR_modify_ldt, bogus_func, us, sizeof(*us));
123 	printf("modify_ldt(%d, ", (int) bogus_func);
124 	print_user_desc(us, "-1");
125 	printf(", %zu) = ", sizeof(*us));
126 	printrc(rc);
127 
128 	puts("+++ exited with 0 +++");
129 
130 	return 0;
131 }
132 
133 #else
134 
135 SKIP_MAIN_UNDEFINED("__NR_modify_ldt && HAVE_STRUCT_USER_DESC");
136 
137 #endif
138