segatools/hooklib/createprocess.c

#include <windows.h>

#include <assert.h>
#include <stdbool.h>
#include <stdint.h>
#include <string.h>

#include "hook/table.h"

#include "hooklib/createprocess.h"

#include "util/dprintf.h"

void createprocess_hook_init();
static BOOL WINAPI my_CreateProcessA(
    LPCSTR                lpApplicationName,
    LPSTR                 lpCommandLine,
    LPSECURITY_ATTRIBUTES lpProcessAttributes,
    LPSECURITY_ATTRIBUTES lpThreadAttributes,
    BOOL                  bInheritHandles,
    DWORD                 dwCreationFlags,
    LPVOID                lpEnvironment,
    LPCSTR                lpCurrentDirectory,
    LPSTARTUPINFOA        lpStartupInfo,
    LPPROCESS_INFORMATION lpProcessInformation
);
BOOL my_CreateProcessW(
    LPCWSTR               lpApplicationName,
    LPWSTR                lpCommandLine,
    LPSECURITY_ATTRIBUTES lpProcessAttributes,
    LPSECURITY_ATTRIBUTES lpThreadAttributes,
    BOOL                  bInheritHandles,
    DWORD                 dwCreationFlags,
    LPVOID                lpEnvironment,
    LPCWSTR               lpCurrentDirectory,
    LPSTARTUPINFOW        lpStartupInfo,
    LPPROCESS_INFORMATION lpProcessInformation
);

static BOOL (WINAPI *next_CreateProcessA)(
    LPCSTR                lpApplicationName,
    LPSTR                 lpCommandLine,
    LPSECURITY_ATTRIBUTES lpProcessAttributes,
    LPSECURITY_ATTRIBUTES lpThreadAttributes,
    BOOL                  bInheritHandles,
    DWORD                 dwCreationFlags,
    LPVOID                lpEnvironment,
    LPCSTR                lpCurrentDirectory,
    LPSTARTUPINFOA        lpStartupInfo,
    LPPROCESS_INFORMATION lpProcessInformation
);

static BOOL (WINAPI *next_CreateProcessW)(
    LPCWSTR               lpApplicationName,
    LPWSTR                lpCommandLine,
    LPSECURITY_ATTRIBUTES lpProcessAttributes,
    LPSECURITY_ATTRIBUTES lpThreadAttributes,
    BOOL                  bInheritHandles,
    DWORD                 dwCreationFlags,
    LPVOID                lpEnvironment,
    LPCWSTR               lpCurrentDirectory,
    LPSTARTUPINFOW        lpStartupInfo,
    LPPROCESS_INFORMATION lpProcessInformation
);

static const struct hook_symbol win32_hooks[] = {
    {
        .name = "CreateProcessA",
        .patch = my_CreateProcessA,
        .link = (void **) &next_CreateProcessA
    },
    {
        .name = "CreateProcessW",
        .patch = my_CreateProcessW,
        .link = (void **) &next_CreateProcessW
    },
};

static bool did_init = false;

static struct process_hook_sym_w *process_syms_w;
static struct process_hook_sym_a *process_syms_a;

static size_t process_nsyms_a = 0;
static size_t process_nsyms_w = 0;

static CRITICAL_SECTION createproc_lock;

HRESULT createprocess_push_hook_w(const wchar_t *name, const wchar_t *head, const wchar_t *tail) {
    struct process_hook_sym_w *new_mem;
    struct process_hook_sym_w *new_proc;
    HRESULT hr;

    assert(name != NULL);
    assert(head != NULL);

    createprocess_hook_init();
    EnterCriticalSection(&createproc_lock);
    
    new_mem = realloc(
            process_syms_w,
            (process_nsyms_w + 1) * sizeof(struct process_hook_sym_w));

    if (new_mem == NULL) {

        LeaveCriticalSection(&createproc_lock);
        return E_OUTOFMEMORY;
    }

    new_proc = &new_mem[process_nsyms_w];
    memset(new_proc, 0, sizeof(*new_proc));
    new_proc->name = name;
    new_proc->head = head;
    new_proc->tail = tail;

    process_syms_w = new_mem;
    process_nsyms_w++;
    
    LeaveCriticalSection(&createproc_lock);
    return S_OK;
}

HRESULT createprocess_push_hook_a(const char *name, const char *head, const char *tail) {
    struct process_hook_sym_a *new_mem;
    struct process_hook_sym_a *new_proc;

    assert(name != NULL);
    assert(head != NULL);

    createprocess_hook_init();

    EnterCriticalSection(&createproc_lock);
    
    new_mem = realloc(
            process_syms_a,
            (process_nsyms_a + 1) * sizeof(struct process_hook_sym_a));

    if (new_mem == NULL) {

        LeaveCriticalSection(&createproc_lock);
        return E_OUTOFMEMORY;
    }

    new_proc = &new_mem[process_nsyms_a];
    memset(new_proc, 0, sizeof(*new_proc));
    new_proc->name = name;
    new_proc->head = head;
    new_proc->tail = tail;

    process_syms_a = new_mem;
    process_nsyms_a++;
    
    LeaveCriticalSection(&createproc_lock);
    return S_OK;
}

void createprocess_hook_init() {
    if (did_init) {
        return;
    }
    did_init = true;

    hook_table_apply(
            NULL,
            "kernel32.dll",
            win32_hooks,
            _countof(win32_hooks));
    InitializeCriticalSection(&createproc_lock);
    dprintf("CreateProcess: Init\n");
}


static BOOL WINAPI my_CreateProcessA(
    LPCSTR                lpApplicationName,
    LPSTR                 lpCommandLine,
    LPSECURITY_ATTRIBUTES lpProcessAttributes,
    LPSECURITY_ATTRIBUTES lpThreadAttributes,
    BOOL                  bInheritHandles,
    DWORD                 dwCreationFlags,
    LPVOID                lpEnvironment,
    LPCSTR                lpCurrentDirectory,
    LPSTARTUPINFOA        lpStartupInfo,
    LPPROCESS_INFORMATION lpProcessInformation
)
{
    for (int i = 0; i < process_nsyms_a; i++) {
        if (strncmp(process_syms_a->name, lpCommandLine, strlen(process_syms_a->name))) {
            continue;
        }

        dprintf("CreateProcess: Hooking child process %s %s\n", lpApplicationName, lpCommandLine);
        char new_cmd[MAX_PATH] = {0};
        strcat_s(new_cmd, MAX_PATH, process_syms_a->head);
        strcat_s(new_cmd, MAX_PATH, lpCommandLine);

        if (process_syms_a->tail != NULL) {
            strcat_s(new_cmd, MAX_PATH, process_syms_a->tail);
        }

        dprintf("CreateProcess: Replaced CreateProcessA %s\n", new_cmd);
        return next_CreateProcessA(
                lpApplicationName,
                new_cmd,
                lpProcessAttributes,
                lpThreadAttributes,
                bInheritHandles,
                dwCreationFlags,
                lpEnvironment,
                lpCurrentDirectory,
                lpStartupInfo,
                lpProcessInformation
            );
    }
    return next_CreateProcessA(
                lpApplicationName,
                lpCommandLine,
                lpProcessAttributes,
                lpThreadAttributes,
                bInheritHandles,
                dwCreationFlags,
                lpEnvironment,
                lpCurrentDirectory,
                lpStartupInfo,
                lpProcessInformation
            );
}

BOOL my_CreateProcessW(
    LPCWSTR               lpApplicationName,
    LPWSTR                lpCommandLine,
    LPSECURITY_ATTRIBUTES lpProcessAttributes,
    LPSECURITY_ATTRIBUTES lpThreadAttributes,
    BOOL                  bInheritHandles,
    DWORD                 dwCreationFlags,
    LPVOID                lpEnvironment,
    LPCWSTR               lpCurrentDirectory,
    LPSTARTUPINFOW        lpStartupInfo,
    LPPROCESS_INFORMATION lpProcessInformation)
{
    return next_CreateProcessW(
        lpApplicationName,
        lpCommandLine,
        lpProcessAttributes,
        lpThreadAttributes,
        bInheritHandles,
        dwCreationFlags,
        lpEnvironment,
        lpCurrentDirectory,
        lpStartupInfo,
        lpProcessInformation
    );
}