1 /*
2 *
3 * Copyright (c) International Business Machines Corp., 2001
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
13 * the GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
18 */
19
20 /*
21 * NAME
22 * modify_ldt02.c
23 *
24 * DESCRIPTION
25 * Testcase to check the error conditions for modify_ldt(2)
26 *
27 * ALGORITHM
28 * block1:
29 * Create a segment at entry 0 and a valid base address.
30 * Read the contents of the segment thru' fs register.
31 * Validate the data.
32 * Write an invalid base address into entry 0.
33 * Read the contents of entry 0 in the child process.
34 * Verify that a SIGSEGV is incurred.
35 *
36 * USAGE
37 * modify_ldt02
38 *
39 * HISTORY
40 * 07/2001 Ported by Wayne Boyer
41 *
42 * RESTRICTIONS
43 * None
44 */
45
46 #include "config.h"
47 #include "test.h"
48
49 TCID_DEFINE(modify_ldt02);
50 int TST_TOTAL = 1;
51
52 #if defined(__i386__) && defined(HAVE_MODIFY_LDT)
53
54 #ifdef HAVE_ASM_LDT_H
55 #include <asm/ldt.h>
56 #endif
57 extern int modify_ldt(int, void *, unsigned long);
58
59 #include <asm/unistd.h>
60 #include <string.h>
61 #include <sys/wait.h>
62 #include <errno.h>
63
64 /* Newer ldt.h files use user_desc, instead of modify_ldt_ldt_s */
65 #ifdef HAVE_STRUCT_USER_DESC
66 typedef struct user_desc modify_ldt_s;
67 #elif HAVE_STRUCT_MODIFY_LDT_LDT_S
68 typedef struct modify_ldt_ldt_s modify_ldt_s;
69 #else
70 typedef struct modify_ldt_ldt_t {
71 unsigned int entry_number;
72 unsigned long int base_addr;
73 unsigned int limit;
74 unsigned int seg_32bit:1;
75 unsigned int contents:2;
76 unsigned int read_exec_only:1;
77 unsigned int limit_in_pages:1;
78 unsigned int seg_not_present:1;
79 unsigned int useable:1;
80 unsigned int empty:25;
81 } modify_ldt_s;
82 #endif
83
84 int create_segment(void *, size_t);
85 int read_segment(unsigned int);
86 void cleanup(void);
87 void setup(void);
88
main(int ac,char ** av)89 int main(int ac, char **av)
90 {
91 int lc;
92
93 int val, pid, status;
94
95 int seg[4];
96
97 tst_parse_opts(ac, av, NULL, NULL);
98
99 setup();
100
101 for (lc = 0; TEST_LOOPING(lc); lc++) {
102 tst_count = 0;
103
104 seg[0] = 12345;
105 if (create_segment(seg, sizeof(seg)) == -1) {
106 tst_brkm(TBROK, cleanup, "Creation of segment failed");
107 }
108
109 val = read_segment(0);
110
111 if (val != seg[0]) {
112 tst_resm(TFAIL, "Invalid value read %d, expected %d",
113 val, seg[0]);
114 } else
115 tst_resm(TPASS, "value read as expected");
116
117 if (create_segment(0, 10) == -1) {
118 tst_brkm(TBROK, cleanup, "Creation of segment failed");
119 }
120
121 tst_old_flush();
122 if ((pid = FORK_OR_VFORK()) == 0) {
123 signal(SIGSEGV, SIG_DFL);
124 val = read_segment(0);
125 exit(1);
126 }
127
128 (void)waitpid(pid, &status, 0);
129
130 if (WEXITSTATUS(status) != 0) {
131 tst_resm(TFAIL, "Did not generate SEGV, child returned "
132 "unexpected status");
133 } else {
134 if (WIFSIGNALED(status) && (WTERMSIG(status) == SIGSEGV))
135 tst_resm(TPASS, "generate SEGV as expected");
136 else
137 tst_resm(TFAIL, "Did not generate SEGV");
138 }
139 }
140 cleanup();
141 tst_exit();
142
143 }
144
create_segment(void * seg,size_t size)145 int create_segment(void *seg, size_t size)
146 {
147 modify_ldt_s entry;
148
149 entry.entry_number = 0;
150 entry.base_addr = (unsigned long)seg;
151 entry.limit = size;
152 entry.seg_32bit = 1;
153 entry.contents = 0;
154 entry.read_exec_only = 0;
155 entry.limit_in_pages = 0;
156 entry.seg_not_present = 0;
157
158 return modify_ldt(1, &entry, sizeof(entry));
159 }
160
read_segment(unsigned int index)161 int read_segment(unsigned int index)
162 {
163 int res;
164 __asm__ __volatile__("\n\
165 push $0x0007;\n\
166 pop %%fs;\n\
167 movl %%fs:(%1), %0":"=r"(res)
168 :"r"(index * sizeof(int)));
169 return res;
170 }
171
setup(void)172 void setup(void)
173 {
174 tst_sig(FORK, DEF_HANDLER, cleanup);
175
176 TEST_PAUSE;
177 }
178
cleanup(void)179 void cleanup(void)
180 {
181
182 }
183 #elif HAVE_MODIFY_LDT
main(void)184 int main(void)
185 {
186 tst_brkm(TCONF,
187 NULL,
188 "modify_ldt is available but not tested on the platform than __i386__");
189 }
190
191 #else /* if defined(__i386__) */
192
main(void)193 int main(void)
194 {
195 tst_resm(TINFO, "modify_ldt02 test only for ix86");
196 tst_exit();
197 }
198
199 #endif /* if defined(__i386__) */
200