Commit | Line | Data |
---|---|---|
9f1d377b ILT |
1 | // relro_test.cc -- test -z relro for gold |
2 | ||
b3adc24a | 3 | // Copyright (C) 2008-2020 Free Software Foundation, Inc. |
9f1d377b ILT |
4 | // Written by Ian Lance Taylor <iant@google.com>. |
5 | ||
6 | // This file is part of gold. | |
7 | ||
8 | // This program is free software; you can redistribute it and/or modify | |
9 | // it under the terms of the GNU General Public License as published by | |
10 | // the Free Software Foundation; either version 3 of the License, or | |
11 | // (at your option) any later version. | |
12 | ||
13 | // This program is distributed in the hope that it will be useful, | |
14 | // but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | // GNU General Public License for more details. | |
17 | ||
18 | // You should have received a copy of the GNU General Public License | |
19 | // along with this program; if not, write to the Free Software | |
20 | // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, | |
21 | // MA 02110-1301, USA. | |
22 | ||
23 | #include <cassert> | |
24 | #include <csignal> | |
7b308235 ILT |
25 | #include <cstdio> |
26 | #include <cstdlib> | |
27 | #include <exception> | |
9f1d377b ILT |
28 | #include <stdint.h> |
29 | #include <unistd.h> | |
30 | ||
2d924fd9 ILT |
31 | // This tests we were linked with a script. If we were linked with a |
32 | // script, relro currently does not work. | |
33 | ||
34 | extern char using_script[] __attribute__ ((weak)); | |
35 | ||
9f1d377b ILT |
36 | // This code is put into a shared library linked with -z relro. |
37 | ||
38 | // i1 and i2 are not relro variables. | |
39 | int i1 = 1; | |
40 | static int i2 = 2; | |
41 | ||
42 | // P1 is a global relro variable. | |
fc497986 | 43 | int* const p1 __attribute__ ((aligned(64))) = &i1; |
9f1d377b ILT |
44 | |
45 | // P2 is a local relro variable. | |
fc497986 | 46 | int* const p2 __attribute__ ((aligned(64))) = &i2; |
9f1d377b | 47 | |
1007b503 CC |
48 | // Add a TLS variable to make sure -z relro works correctly with TLS. |
49 | __thread int i3 = 1; | |
50 | ||
9f1d377b ILT |
51 | // Test symbol addresses. |
52 | ||
53 | bool | |
54 | t1() | |
55 | { | |
2d924fd9 ILT |
56 | if (using_script) |
57 | return true; | |
58 | ||
9f1d377b ILT |
59 | void* i1addr = static_cast<void*>(&i1); |
60 | void* i2addr = static_cast<void*>(&i2); | |
61 | const void* p1addr = static_cast<const void*>(&p1); | |
62 | const void* p2addr = static_cast<const void*>(&p2); | |
63 | ||
64 | // The relro variables should precede the non-relro variables in the | |
65 | // memory image. | |
66 | assert(i1addr > p1addr); | |
67 | assert(i1addr > p2addr); | |
68 | assert(i2addr > p1addr); | |
69 | assert(i2addr > p2addr); | |
70 | ||
71 | // The relro variables should not be on the same page as the | |
72 | // non-relro variables. | |
73 | const size_t page_size = getpagesize(); | |
74 | uintptr_t i1page = reinterpret_cast<uintptr_t>(i1addr) & ~ (page_size - 1); | |
75 | uintptr_t i2page = reinterpret_cast<uintptr_t>(i2addr) & ~ (page_size - 1); | |
76 | uintptr_t p1page = reinterpret_cast<uintptr_t>(p1addr) & ~ (page_size - 1); | |
77 | uintptr_t p2page = reinterpret_cast<uintptr_t>(p2addr) & ~ (page_size - 1); | |
78 | assert(i1page != p1page); | |
79 | assert(i1page != p2page); | |
80 | assert(i2page != p1page); | |
81 | assert(i2page != p2page); | |
1007b503 | 82 | assert(i3 == 1); |
9f1d377b ILT |
83 | |
84 | return true; | |
85 | } | |
86 | ||
7b308235 ILT |
87 | // Tell terminate handler that we are throwing from a signal handler. |
88 | ||
89 | static bool throwing; | |
90 | ||
9f1d377b ILT |
91 | // A signal handler for SIGSEGV. |
92 | ||
93 | extern "C" | |
94 | void | |
95 | sigsegv_handler(int) | |
96 | { | |
7b308235 | 97 | throwing = true; |
9f1d377b ILT |
98 | throw 0; |
99 | } | |
100 | ||
7b308235 ILT |
101 | // The original terminate handler. |
102 | ||
103 | std::terminate_handler orig_terminate; | |
104 | ||
105 | // Throwing an exception out of a signal handler doesn't always work | |
106 | // reliably. When that happens the program will call terminate. We | |
107 | // set a terminate handler to indicate that the test probably passed. | |
108 | ||
109 | void | |
110 | terminate_handler() | |
111 | { | |
112 | if (!throwing) | |
113 | { | |
114 | orig_terminate(); | |
115 | ::exit(EXIT_FAILURE); | |
116 | } | |
117 | fprintf(stderr, | |
118 | "relro_test: terminate called due to failure to throw through signal handler\n"); | |
119 | fprintf(stderr, "relro_test: assuming test succeeded\n"); | |
120 | ::exit(EXIT_SUCCESS); | |
121 | } | |
122 | ||
9f1d377b ILT |
123 | // Use a separate function to throw the exception, so that we don't |
124 | // need to use -fnon-call-exceptions. | |
125 | ||
126 | void f2() __attribute__ ((noinline)); | |
127 | void | |
128 | f2() | |
129 | { | |
130 | int** pp1 = const_cast<int**>(&p1); | |
131 | *pp1 = &i2; | |
132 | ||
133 | // We shouldn't get here--the assignment to *pp1 should write to | |
134 | // memory which the dynamic linker marked as read-only, giving us a | |
135 | // SIGSEGV, causing sigsegv_handler to be invoked, to throw past us. | |
136 | assert(0); | |
137 | } | |
138 | ||
139 | // Changing a relro variable should give us a SIGSEGV. | |
140 | ||
141 | bool | |
142 | t2() | |
143 | { | |
2d924fd9 ILT |
144 | if (using_script) |
145 | return true; | |
146 | ||
9f1d377b | 147 | signal(SIGSEGV, sigsegv_handler); |
7b308235 | 148 | orig_terminate = std::set_terminate(terminate_handler); |
9f1d377b ILT |
149 | |
150 | try | |
151 | { | |
152 | f2(); | |
153 | return false; | |
154 | } | |
155 | catch (int i) | |
156 | { | |
157 | assert(i == 0); | |
158 | return true; | |
159 | } | |
160 | } |