1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
|
// RUN: %clangxx_cfi_dso -DSHARED_LIB %s -fPIC -shared -o %t1-so.so
// RUN: %clangxx_cfi_dso %s -o %t1
// RUN: %expect_crash %t1 2>&1 | FileCheck --check-prefix=CFI %s
// RUN: %expect_crash %t1 cast 2>&1 | FileCheck --check-prefix=CFI-CAST %s
// RUN: %expect_crash %t1 dlclose 2>&1 | FileCheck --check-prefix=CFI %s
// RUN: %clangxx_cfi_dso -DB32 -DSHARED_LIB %s -fPIC -shared -o %t2-so.so
// RUN: %clangxx_cfi_dso -DB32 %s -o %t2
// RUN: %expect_crash %t2 2>&1 | FileCheck --check-prefix=CFI %s
// RUN: %expect_crash %t2 cast 2>&1 | FileCheck --check-prefix=CFI-CAST %s
// RUN: %expect_crash %t2 dlclose 2>&1 | FileCheck --check-prefix=CFI %s
// RUN: %clangxx_cfi_dso -DB64 -DSHARED_LIB %s -fPIC -shared -o %t3-so.so
// RUN: %clangxx_cfi_dso -DB64 %s -o %t3
// RUN: %expect_crash %t3 2>&1 | FileCheck --check-prefix=CFI %s
// RUN: %expect_crash %t3 cast 2>&1 | FileCheck --check-prefix=CFI-CAST %s
// RUN: %expect_crash %t3 dlclose 2>&1 | FileCheck --check-prefix=CFI %s
// RUN: %clangxx_cfi_dso -DBM -DSHARED_LIB %s -fPIC -shared -o %t4-so.so
// RUN: %clangxx_cfi_dso -DBM %s -o %t4
// RUN: %expect_crash %t4 2>&1 | FileCheck --check-prefix=CFI %s
// RUN: %expect_crash %t4 cast 2>&1 | FileCheck --check-prefix=CFI-CAST %s
// RUN: %expect_crash %t4 dlclose 2>&1 | FileCheck --check-prefix=CFI %s
// RUN: %clangxx -g -DBM -DSHARED_LIB -DNOCFI %s -fPIC -shared -o %t5-so.so
// RUN: %clangxx -g -DBM -DNOCFI %s -ldl -o %t5
// RUN: %t5 2>&1 | FileCheck --check-prefix=NCFI %s
// RUN: %t5 cast 2>&1 | FileCheck --check-prefix=NCFI %s
// RUN: %t5 dlclose 2>&1 | FileCheck --check-prefix=NCFI %s
// Test that calls to uninstrumented library are unchecked.
// RUN: %clangxx -DBM -DSHARED_LIB %s -fPIC -shared -o %t6-so.so
// RUN: %clangxx_cfi_dso -DBM %s -o %t6
// RUN: %t6 2>&1 | FileCheck --check-prefix=NCFI %s
// RUN: %t6 cast 2>&1 | FileCheck --check-prefix=NCFI %s
// Call-after-dlclose is checked on the caller side.
// RUN: %expect_crash %t6 dlclose 2>&1 | FileCheck --check-prefix=CFI %s
// Tests calls into dlopen-ed library.
// REQUIRES: cxxabi
#include <assert.h>
#include <dlfcn.h>
#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <sys/mman.h>
#include <string>
struct A {
virtual void f();
};
#ifdef SHARED_LIB
#include "../../utils.h"
struct B {
virtual void f();
};
void B::f() {}
extern "C" void *create_B() {
create_derivers<B>();
return (void *)(new B());
}
extern "C" __attribute__((aligned(4096))) void do_nothing() {}
#else
void A::f() {}
static const int kCodeAlign = 4096;
static const int kCodeSize = 4096;
static char saved_code[kCodeSize];
static char *real_start;
static void save_code(char *p) {
real_start = (char *)(((uintptr_t)p) & ~(kCodeAlign - 1));
memcpy(saved_code, real_start, kCodeSize);
}
static void restore_code() {
char *code =
(char *)mmap(real_start, kCodeSize, PROT_READ | PROT_WRITE | PROT_EXEC,
MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED, 0, 0);
assert(code == real_start);
memcpy(code, saved_code, kCodeSize);
__builtin___clear_cache(code, code + kCodeSize);
}
int main(int argc, char *argv[]) {
const bool test_cast = argc > 1 && strcmp(argv[1], "cast") == 0;
const bool test_dlclose = argc > 1 && strcmp(argv[1], "dlclose") == 0;
std::string name = std::string(argv[0]) + "-so.so";
void *handle = dlopen(name.c_str(), RTLD_NOW);
assert(handle);
void *(*create_B)() = (void *(*)())dlsym(handle, "create_B");
assert(create_B);
void *p = create_B();
A *a;
// CFI: =0=
// CFI-CAST: =0=
// NCFI: =0=
fprintf(stderr, "=0=\n");
if (test_cast) {
// Test cast. BOOM.
a = (A*)p;
} else {
// Invisible to CFI. Test virtual call later.
memcpy(&a, &p, sizeof(a));
}
// CFI: =1=
// CFI-CAST-NOT: =1=
// NCFI: =1=
fprintf(stderr, "=1=\n");
if (test_dlclose) {
// Imitate an attacker sneaking in an executable page where a dlclose()d
// library was loaded. This needs to pass w/o CFI, so for the testing
// purpose, we just copy the bytes of a "void f() {}" function back and
// forth.
void (*do_nothing)() = (void (*)())dlsym(handle, "do_nothing");
assert(do_nothing);
save_code((char *)do_nothing);
int res = dlclose(handle);
assert(res == 0);
restore_code();
do_nothing(); // UB here
} else {
a->f(); // UB here
}
// CFI-NOT: =2=
// CFI-CAST-NOT: =2=
// NCFI: =2=
fprintf(stderr, "=2=\n");
}
#endif
|
