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
89 #define FAILED 1
90
main(int ac,char ** av)91 int main(int ac, char **av)
92 {
93 int lc;
94
95 int val, pid, status;
96
97 int flag;
98 int seg[4];
99
100 tst_parse_opts(ac, av, NULL, NULL);
101
102 setup(); /* global setup */
103
104 /* The following loop checks looping state if -i option given */
105 for (lc = 0; TEST_LOOPING(lc); lc++) {
106
107 /* reset tst_count in case we are looping */
108 tst_count = 0;
109
110 //block1:
111 tst_resm(TINFO, "Enter block 1");
112 flag = 0;
113
114 seg[0] = 12345;
115 if (create_segment(seg, sizeof(seg)) == -1) {
116 tst_brkm(TINFO, cleanup, "Creation of segment failed");
117 }
118
119 val = read_segment(0);
120
121 if (val != seg[0]) {
122 tst_resm(TFAIL, "Invalid value read %d, expected %d",
123 val, seg[0]);
124 flag = FAILED;
125 }
126
127 if (flag) {
128 tst_resm(TINFO, "block 1 FAILED");
129 } else {
130 tst_resm(TINFO, "block 1 PASSED");
131 }
132
133 tst_resm(TINFO, "Exit block 1");
134
135 //block2:
136 tst_resm(TINFO, "Enter block 2");
137 flag = 0;
138
139 if (create_segment(0, 10) == -1) {
140 tst_brkm(TINFO, cleanup, "Creation of segment failed");
141 }
142
143 tst_old_flush();
144 if ((pid = FORK_OR_VFORK()) == 0) {
145 val = read_segment(0);
146 exit(1);
147 }
148
149 (void)waitpid(pid, &status, 0);
150
151 if (WEXITSTATUS(status) != 0) {
152 flag = FAILED;
153 tst_resm(TFAIL, "Did not generate SEGV, child returned "
154 "unexpected status");
155 }
156
157 if (flag) {
158 tst_resm(TINFO, "block 2 FAILED");
159 } else {
160 tst_resm(TINFO, "block 2 PASSED");
161 }
162 }
163 cleanup();
164 tst_exit();
165
166 }
167
create_segment(void * seg,size_t size)168 int create_segment(void *seg, size_t size)
169 {
170 modify_ldt_s entry;
171
172 entry.entry_number = 0;
173 entry.base_addr = (unsigned long)seg;
174 entry.limit = size;
175 entry.seg_32bit = 1;
176 entry.contents = 0;
177 entry.read_exec_only = 0;
178 entry.limit_in_pages = 0;
179 entry.seg_not_present = 0;
180
181 return modify_ldt(1, &entry, sizeof(entry));
182 }
183
read_segment(unsigned int index)184 int read_segment(unsigned int index)
185 {
186 int res;
187 __asm__ __volatile__("\n\
188 push $0x0007;\n\
189 pop %%fs;\n\
190 movl %%fs:(%1), %0":"=r"(res)
191 :"r"(index * sizeof(int)));
192 return res;
193 }
194
sigsegv_handler(int sig)195 void sigsegv_handler(int sig)
196 {
197 tst_resm(TINFO, "received signal: %d", sig);
198 exit(0);
199 }
200
201 /*
202 * setup() - performs all ONE TIME setup for this test
203 */
setup(void)204 void setup(void)
205 {
206 struct sigaction act;
207
208 memset(&act, 0, sizeof(act));
209 sigemptyset(&act.sa_mask);
210
211 tst_sig(FORK, DEF_HANDLER, cleanup);
212
213 act.sa_handler = sigsegv_handler;
214 (void)sigaction(SIGSEGV, &act, NULL);
215
216 TEST_PAUSE;
217 }
218
219 /*
220 * cleanup() - performs all the ONE TIME cleanup for this test at completion
221 * or premature exit.
222 */
cleanup(void)223 void cleanup(void)
224 {
225
226 }
227 #elif HAVE_MODIFY_LDT
main(void)228 int main(void)
229 {
230 tst_brkm(TCONF,
231 NULL,
232 "modify_ldt is available but not tested on the platform than __i386__");
233 }
234
235 #else /* if defined(__i386__) */
236
main(void)237 int main(void)
238 {
239 tst_resm(TINFO, "modify_ldt02 test only for ix86");
240 tst_exit();
241 }
242
243 #endif /* if defined(__i386__) */
244