1 /*
2 * Copyright (C) 2017 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include <assert.h>
18 #include <stdint.h>
19 #include <stdlib.h>
20
21 // This library is built for all targets, including host tests, so __cfi_slowpath may not be
22 // present. But it is only used in the bionic loader tests.
23 extern "C" __attribute__((weak)) void __cfi_slowpath(uint64_t, void*);
24
25 static size_t g_count;
26 static uint64_t g_last_type_id;
27 static void* g_last_address;
28 static void* g_last_diag;
29
30 extern "C" {
31
32 // Make sure the library crosses at least one kLibraryAlignment(=256KB) boundary.
33 char bss[1024 * 1024];
34
35 // Mock a CFI-enabled library without relying on the compiler.
__cfi_check(uint64_t CallSiteTypeId,void * TargetAddr,void * Diag)36 __attribute__((aligned(4096))) void __cfi_check(uint64_t CallSiteTypeId, void* TargetAddr,
37 void* Diag) {
38 ++g_count;
39 g_last_type_id = CallSiteTypeId;
40 g_last_address = TargetAddr;
41 g_last_diag = Diag;
42 }
43
get_count()44 size_t get_count() {
45 return g_count;
46 }
47
get_last_type_id()48 uint64_t get_last_type_id() {
49 return g_last_type_id;
50 }
51
get_last_address()52 void* get_last_address() {
53 return g_last_address;
54 }
55
get_last_diag()56 void* get_last_diag() {
57 return g_last_diag;
58 }
59
get_global_address()60 void* get_global_address() {
61 return &g_count;
62 }
63 }
64
65 // Check that CFI is set up in module constructors and destructors.
66 struct A {
check_cfi_selfA67 void check_cfi_self() {
68 g_last_type_id = 0;
69 assert(&__cfi_slowpath);
70 // CFI check for an address inside this DSO. This goes to the current module's __cfi_check,
71 // which updates g_last_type_id.
72 __cfi_slowpath(13, static_cast<void*>(&g_last_type_id));
73 assert(g_last_type_id == 13);
74 // CFI check for a libc function. This never goes into this module's __cfi_check, and must pass.
75 __cfi_slowpath(14, reinterpret_cast<void*>(&exit));
76 assert(g_last_type_id == 13);
77 }
AA78 A() {
79 check_cfi_self();
80 }
~AA81 ~A() {
82 check_cfi_self();
83 }
84 } a;
85