enable_execute_stack_test.c revision 1.1.1.1 
1//===-- enable_execute_stack_test.c - Test __enable_execute_stack ----------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is dual licensed under the MIT and the University of Illinois Open
6// Source Licenses. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9
10
11#include <stdio.h>
12#include <string.h>
13#include <stdint.h>
14#if defined(_WIN32)
15#include <windows.h>
16void __clear_cache(void* start, void* end)
17{
18    if (!FlushInstructionCache(GetCurrentProcess(), start, end-start))
19        exit(1);
20}
21void __enable_execute_stack(void *addr)
22{
23    MEMORY_BASIC_INFORMATION b;
24
25    if (!VirtualQuery(addr, &b, sizeof(b)))
26        exit(1);
27    if (!VirtualProtect(b.BaseAddress, b.RegionSize, PAGE_EXECUTE_READWRITE, &b.Protect))
28        exit(1);
29}
30#else
31#include <sys/mman.h>
32extern void __clear_cache(void* start, void* end);
33extern void __enable_execute_stack(void* addr);
34#endif
35
36typedef int (*pfunc)(void);
37
38int func1()
39{
40    return 1;
41}
42
43int func2()
44{
45    return 2;
46}
47
48
49
50
51int main()
52{
53    unsigned char execution_buffer[128];
54    // mark stack page containing execution_buffer to be executable
55    __enable_execute_stack(execution_buffer);
56
57    // verify you can copy and execute a function
58    memcpy(execution_buffer, (void *)(uintptr_t)&func1, 128);
59    __clear_cache(execution_buffer, &execution_buffer[128]);
60    pfunc f1 = (pfunc)(uintptr_t)execution_buffer;
61    if ((*f1)() != 1)
62        return 1;
63
64    // verify you can overwrite a function with another
65    memcpy(execution_buffer, (void *)(uintptr_t)&func2, 128);
66    __clear_cache(execution_buffer, &execution_buffer[128]);
67    pfunc f2 = (pfunc)(uintptr_t)execution_buffer;
68    if ((*f2)() != 2)
69        return 1;
70
71    return 0;
72}
73