#include <windows.h>

int p_data[10], idx;
int load_kernel32_base(void)
{
    struct _ldr {
        int module_list;
    };
   
    struct _peb {
        struct _ldr *ldr;
    };
#define PEB_OFFSET        30h
#define LDR_OFFSET        0x0c
#define MODULELIST_OFFSET 0x1c
#define UNKNOWN_A         0x08
#define UNKNOWN_B         0x20
#define UNKNOWN_C         12
#define LOCK_DATA(__data)      \
    p_data[idx++] = (__data)
#define UNLOCK_DATA(__data)    \
    (__data) = p_data[--idx]

    struct _peb *peb;
    int kernel32, tmp;

    __asm mov eax, fs:[PEB_OFFSET]
    __asm mov dword ptr [peb], eax

    //LOCK_DATA(peb->ldr->module_list);
    LOCK_DATA((int)peb->ldr);
    peb->ldr = (struct _ldr *)*(int *)((int)peb + LDR_OFFSET);
    peb->ldr->module_list = *(int *)((int)peb->ldr + MODULELIST_OFFSET);
   
    do {
        kernel32 = *(int *)((int)peb->ldr->module_list + UNKNOWN_A);
        tmp = *(int *)((int)peb->ldr->module_list + UNKNOWN_B);
        peb->ldr->module_list = *(int *)peb->ldr->module_list;
    } while (*(short *)(tmp + UNKNOWN_C * sizeof(short)) != 0);
    UNLOCK_DATA((int)peb->ldr);
    //UNLOCK_DATA(peb->ldr->module_list);

   
    return kernel32;
}

typedef FARPROC (WINAPI *FUNC_G)(HMODULE, LPCSTR);
typedef HMODULE(WINAPI *FUNC_L)(LPCTSTR);
typedef int (WINAPI *FUNC_M)(HWND, LPCTSTR, LPCTSTR, UINT);
typedef VOID (WINAPI *FUNC_E)(UINT);

const char *usr_literal[] = {
    "GetProcAddress",
    "LoadLibraryA",
    "user32",
    "MessageBoxA",
    "hello",
    "ExitProcess"
};

FUNC_G load_GetProcAddress(int kernel32)
{
#define RVA_2_VA(__rva)      ((kernel32) + (__rva))
#define MY_PREFIX(__name)    (my_##__name)
    int offset;
    IMAGE_NT_HEADERS *nt_headers;
    IMAGE_EXPORT_DIRECTORY *exp_dir;
    int ent, eno, ordin, eat;
    char *system_literal;
    unsigned int idx;
    FUNC_G MY_PREFIX(GetProcAddress);


    offset = ((IMAGE_DOS_HEADER *)kernel32)->e_lfanew;
    nt_headers = (IMAGE_NT_HEADERS *)RVA_2_VA(offset);
    offset = nt_headers->OptionalHeader.DataDirectory->VirtualAddress;
    exp_dir = (IMAGE_EXPORT_DIRECTORY *)RVA_2_VA(offset);
    offset = *(int *)(RVA_2_VA((int)exp_dir->AddressOfNames));
    ent = RVA_2_VA(offset);
    system_literal = (char *)ent;
    for (idx = 0; idx < exp_dir->NumberOfNames; idx++) {
        if (strcmp(system_literal, usr_literal[0])) {
            system_literal += strlen(system_literal) + 1;
        } else {
            break;
        }
    }
    eno = RVA_2_VA(exp_dir->AddressOfNameOrdinals);
    ordin = *(short *)(eno + idx * 2);
    eat = RVA_2_VA(exp_dir->AddressOfFunctions);
    offset = *(int *)(eat + idx * 4);
    return my_GetProcAddress = (FUNC_G)RVA_2_VA(offset);
}

FUNC_L load_LoadLibraryA(FUNC_G func_g, int kernel32)
{
    FUNC_L MY_PREFIX(LoadLibraryA);

    return my_LoadLibraryA =
        (FUNC_L)func_g((HMODULE)kernel32, (LPCSTR)usr_literal[1]);

}

FUNC_M load_MessageBoxA(FUNC_G func_g, FUNC_L func_l)
{
    FUNC_M MY_PREFIX(MessageBoxA);

    return my_MessageBoxA =
        (FUNC_M)(func_g((HMODULE)func_l((LPCSTR)usr_literal[2]),
            (LPCSTR)usr_literal[3]));
}

FUNC_E load_ExitProcess(FUNC_G func_g, int kernel32)
{
    FUNC_E MY_PREFIX(ExitProcess);

    return my_ExitProcess =
        (FUNC_E)func_g((HMODULE)kernel32, (LPCSTR)usr_literal[5]);
}

enum func_type_t {
    GetProcAddress_E = 0,
    LoadLibraryA_E,
    MessageBoxA_E,
    ExitProcess_E,
    FUNC_MAX_E
};
int show_my_function(int addr, int type)
{
    switch(type) {
    case MessageBoxA_E:
        {
            FUNC_M func_m = (FUNC_M)addr;
            func_m(NULL, usr_literal[4], NULL, MB_OK);
        }
    break;
    case ExitProcess_E:
        {
            FUNC_E func_e = (FUNC_E)addr;
            func_e(0);
        }
    break;
    default:

    break;
    }
   
    return 0;
}

int main(int argc, char *argv[])
{
    int kernel_base;
    int func[FUNC_MAX_E];

    kernel_base = load_kernel32_base();
    func[GetProcAddress_E] = (int)load_GetProcAddress(kernel_base);
    func[LoadLibraryA_E] =
        (int)load_LoadLibraryA((FUNC_G)func[GetProcAddress_E], kernel_base);
    func[MessageBoxA_E] =
        (int)load_MessageBoxA((FUNC_G)func[GetProcAddress_E],
            (FUNC_L)func[LoadLibraryA_E]);
    func[ExitProcess_E] =
        (int)load_ExitProcess((FUNC_G)func[GetProcAddress_E], kernel_base);
   
    show_my_function(func[MessageBoxA_E], MessageBoxA_E);
    show_my_function(func[ExitProcess_E], ExitProcess_E);

    return 0;
}

对您的大作"一个shellcode的实例"c化了,有几个偏移能否帮着命名下,我懒的去细翻nt和pe的结构了,代码用vc6直接能跑
主要是这几个
#define UNKNOWN_A         0x08
#define UNKNOWN_B         0x20
#define UNKNOWN_C         12


[ 本帖最后由 bccnyouke 于 2012-11-23 21:08 编辑 ]

感谢水哥的建议,互相学习,共同进步