obs-studio/UI/win-update/updater/init-hook-files.c

#include <windows.h>
#include <strsafe.h>
#include <shlobj.h>
#include <stdbool.h>
#include <aclapi.h>
#include <sddl.h>

static bool add_aap_perms(const wchar_t *dir)
{
	PSECURITY_DESCRIPTOR sd = NULL;
	SID *aap_sid = NULL;
	SID *bu_sid = NULL;
	PACL new_dacl1 = NULL;
	PACL new_dacl2 = NULL;
	bool success = false;

	PACL dacl;
	if (GetNamedSecurityInfoW(dir, SE_FILE_OBJECT,
				  DACL_SECURITY_INFORMATION, NULL, NULL, &dacl,
				  NULL, &sd) != ERROR_SUCCESS) {
		goto fail;
	}

	EXPLICIT_ACCESSW ea = {0};
	ea.grfAccessPermissions = GENERIC_READ | GENERIC_EXECUTE;
	ea.grfAccessMode = GRANT_ACCESS;
	ea.grfInheritance = SUB_CONTAINERS_AND_OBJECTS_INHERIT;
	ea.Trustee.TrusteeForm = TRUSTEE_IS_SID;

	/* ALL_APP_PACKAGES */
	ConvertStringSidToSidW(L"S-1-15-2-1", &aap_sid);
	ea.Trustee.ptstrName = (wchar_t *)aap_sid;

	if (SetEntriesInAclW(1, &ea, dacl, &new_dacl1) != ERROR_SUCCESS) {
		goto fail;
	}

	ea.grfAccessPermissions = GENERIC_READ | GENERIC_WRITE |
				  GENERIC_EXECUTE;

	/* BUILTIN_USERS */
	ConvertStringSidToSidW(L"S-1-5-32-545", &bu_sid);
	ea.Trustee.ptstrName = (wchar_t *)bu_sid;

	DWORD s = SetEntriesInAclW(1, &ea, new_dacl1, &new_dacl2);
	if (s != ERROR_SUCCESS) {
		goto fail;
	}

	if (SetNamedSecurityInfoW((wchar_t *)dir, SE_FILE_OBJECT,
				  DACL_SECURITY_INFORMATION, NULL, NULL,
				  new_dacl2, NULL) != ERROR_SUCCESS) {
		goto fail;
	}

	success = true;
fail:
	if (sd)
		LocalFree(sd);
	if (new_dacl1)
		LocalFree(new_dacl1);
	if (new_dacl2)
		LocalFree(new_dacl2);
	if (aap_sid)
		LocalFree(aap_sid);
	if (bu_sid)
		LocalFree(bu_sid);
	return success;
}

static inline bool file_exists(const wchar_t *path)
{
	WIN32_FIND_DATAW wfd;
	HANDLE h = FindFirstFileW(path, &wfd);
	if (h == INVALID_HANDLE_VALUE)
		return false;
	FindClose(h);
	return true;
}

static LSTATUS get_reg(HKEY hkey, LPCWSTR sub_key, LPCWSTR value_name, bool b64)
{
	HKEY key;
	LSTATUS status;
	DWORD flags = b64 ? KEY_WOW64_64KEY : KEY_WOW64_32KEY;
	DWORD size = sizeof(DWORD);
	DWORD val;

	status = RegOpenKeyEx(hkey, sub_key, 0, KEY_READ | flags, &key);
	if (status == ERROR_SUCCESS) {
		status = RegQueryValueExW(key, value_name, NULL, NULL,
					  (LPBYTE)&val, &size);
		RegCloseKey(key);
	}
	return status;
}

#define get_programdata_path(path, subpath)                        \
	do {                                                       \
		SHGetFolderPathW(NULL, CSIDL_COMMON_APPDATA, NULL, \
				 SHGFP_TYPE_CURRENT, path);        \
		StringCbCatW(path, sizeof(path), L"\\");           \
		StringCbCatW(path, sizeof(path), subpath);         \
	} while (false)

#define make_filename(str, name, ext)                                \
	do {                                                         \
		StringCbCatW(str, sizeof(str), name);                \
		StringCbCatW(str, sizeof(str), b64 ? L"64" : L"32"); \
		StringCbCatW(str, sizeof(str), ext);                 \
	} while (false)

#define IMPLICIT_LAYERS L"SOFTWARE\\Khronos\\Vulkan\\ImplicitLayers"
#define HOOK_LOCATION L"\\data\\obs-plugins\\win-capture\\"

static bool update_hook_file(bool b64)
{
	wchar_t temp[MAX_PATH];
	wchar_t src[MAX_PATH];
	wchar_t dst[MAX_PATH];
	wchar_t src_json[MAX_PATH];
	wchar_t dst_json[MAX_PATH];

	GetCurrentDirectoryW(_countof(src_json), src_json);
	StringCbCat(src_json, sizeof(src_json), HOOK_LOCATION);
	make_filename(src_json, L"obs-vulkan", L".json");

	GetCurrentDirectoryW(_countof(src), src);
	StringCbCat(src, sizeof(src), HOOK_LOCATION);
	make_filename(src, L"graphics-hook", L".dll");

	get_programdata_path(temp, L"obs-studio-hook\\");
	StringCbCopyW(dst_json, sizeof(dst_json), temp);
	StringCbCopyW(dst, sizeof(dst), temp);
	make_filename(dst_json, L"obs-vulkan", L".json");
	make_filename(dst, L"graphics-hook", L".dll");

	if (!file_exists(src)) {
		return false;
	}

	CreateDirectoryW(temp, NULL);
	add_aap_perms(temp);
	CopyFileW(src, dst, false);
	CopyFileW(src_json, dst_json, false);
	return true;
}

static void update_vulkan_registry(bool b64)
{
	DWORD flags = b64 ? KEY_WOW64_64KEY : KEY_WOW64_32KEY;
	wchar_t path[MAX_PATH];
	DWORD temp;
	LSTATUS s;
	HKEY key;

	get_programdata_path(path, L"obs-studio-hook\\");
	make_filename(path, L"obs-vulkan", L".json");

	s = get_reg(HKEY_CURRENT_USER, IMPLICIT_LAYERS, path, b64);
	if (s == ERROR_SUCCESS) {
		s = RegOpenKeyEx(HKEY_CURRENT_USER, IMPLICIT_LAYERS, 0,
				 KEY_WRITE | flags, &key);
		if (s == ERROR_SUCCESS) {
			RegDeleteValueW(key, path);
			RegCloseKey(key);
		}
	}

	s = get_reg(HKEY_LOCAL_MACHINE, IMPLICIT_LAYERS, path, b64);
	if (s == ERROR_SUCCESS) {
		return;
	}

	/* ------------------- */

	s = RegCreateKeyExW(HKEY_LOCAL_MACHINE, IMPLICIT_LAYERS, 0, NULL, 0,
			    KEY_WRITE | flags, NULL, &key, &temp);
	if (s != ERROR_SUCCESS) {
		goto finish;
	}

	DWORD zero = 0;
	s = RegSetValueExW(key, path, 0, REG_DWORD, (const BYTE *)&zero,
			   sizeof(zero));
	if (s != ERROR_SUCCESS) {
		goto finish;
	}

finish:
	if (key)
		RegCloseKey(key);
}

void UpdateHookFiles(void)
{
	if (update_hook_file(true))
		update_vulkan_registry(true);
	if (update_hook_file(false))
		update_vulkan_registry(false);
}