main.c

/* Copyright(c) 2018 Matthieu Buffet

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files(the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions :

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE. */

#pragma warning(push, 0)
#define WIN32_NO_STATUS
#include <Windows.h>
#include <stdio.h>
#include <Winternl.h>
#undef WIN32_NO_STATUS
#include <ntstatus.h>
#pragma warning(pop)

// Object manager specific access rights from wdm.h
#define DIRECTORY_QUERY                 (0x0001)
#define DIRECTORY_TRAVERSE              (0x0002)

// Struct definition from MSDN's help for NtQueryDirectoryObject (no header file)
typedef struct _OBJECT_DIRECTORY_INFORMATION {
	UNICODE_STRING Name;
	UNICODE_STRING TypeName;
} OBJECT_DIRECTORY_INFORMATION, *POBJECT_DIRECTORY_INFORMATION;

// ntdll.dll internal functions without header
typedef VOID(WINAPI *_RtlInitUnicodeString)(
	_Inout_  PUNICODE_STRING DestinationString,
	_In_opt_ PCWSTR          SourceString
	);
typedef NTSTATUS (WINAPI *_NtOpenDirectoryObject)(
	_Out_ PHANDLE            DirectoryHandle,
	_In_  ACCESS_MASK        DesiredAccess,
	_In_  POBJECT_ATTRIBUTES ObjectAttributes
);
typedef NTSTATUS (WINAPI *_NtQueryDirectoryObject)(
	_In_      HANDLE  DirectoryHandle,
	_Out_opt_ PVOID   Buffer,
	_In_      ULONG   Length,
	_In_      BOOLEAN ReturnSingleEntry,
	_In_      BOOLEAN RestartScan,
	_Inout_   PULONG  Context,
	_Out_opt_ PULONG  ReturnLength
);
typedef NTSTATUS (WINAPI *_NtOpenSymbolicLinkObject)(
	_Out_ PHANDLE            LinkHandle,
	_In_  ACCESS_MASK        DesiredAccess,
	_In_  POBJECT_ATTRIBUTES ObjectAttributes
);
typedef NTSTATUS (WINAPI *_NtQuerySymbolicLinkObject)(
	_In_      HANDLE          LinkHandle,
	_Inout_   PUNICODE_STRING LinkTarget,
	_Out_opt_ PULONG          ReturnedLength
);

typedef struct _obj_entry_t {
	SIZE_T entrySize;
	SIZE_T childObjCount;
	PWSTR pwszName;
	PWSTR pwszTypeName;
	PWSTR pwszSymlinkTarget;
	struct _obj_entry_t *pChildObj[1];
} obj_entry_t;

// Global function pointers

static _RtlInitUnicodeString pRtlInitUnicodeString = NULL;
static _NtOpenDirectoryObject pNtOpenDirectoryObject = NULL;
static _NtQueryDirectoryObject pNtQueryDirectoryObject = NULL;
static _NtOpenSymbolicLinkObject pNtOpenSymbolicLinkObject = NULL;
static _NtQuerySymbolicLinkObject pNtQuerySymbolicLinkObject = NULL;

void print_help()
{
	fprintf(stderr, "Usage: lsobj [-R to recurse] [directory path, otherwise \\ is listed]\n");
}

int cmp_obj_type_and_names(obj_entry_t *a, obj_entry_t *b)
{
	int res = _wcsicmp(a->pwszTypeName, b->pwszTypeName);
	if (res == 0)
		res = _wcsicmp(a->pwszName, b->pwszName);
	return res;
}

int cmp_obj_names(obj_entry_t *a, obj_entry_t *b)
{
	return _wcsicmp(a->pwszName, b->pwszName);
}

/**
 * Insertion sort applied to all child objects of the given directory,
 * using the given comparison function (which must take two pointers
 * to obj_entry_t and return a <0 , =0 or >0 int).
 */
VOID sort_child_objects_by(obj_entry_t *root, int (*cmp_func)(obj_entry_t*, obj_entry_t*))
{
	for (SIZE_T i = 1; i < root->childObjCount; i++)
	{
		obj_entry_t *to_insert = root->pChildObj[i];
		SIZE_T j = i;
		while (j > 0 && cmp_func(root->pChildObj[j-1], to_insert) >= 0)
		{
			root->pChildObj[j] = root->pChildObj[j-1];
			j--;
		}
		root->pChildObj[j] = to_insert;
	}
}

PVOID safe_alloc(SIZE_T bytes)
{
	void *res = calloc(bytes, 1);
	if (res == NULL)
	{
		printf(" [!] Out of memory\n");
		exit(1);
	}
	return res;
}

PVOID safe_realloc(PVOID buffer, SIZE_T bytes)
{
	PVOID res = realloc(buffer, bytes);
	if (res == NULL)
	{
		printf(" [!] Out of memory\n");
		exit(1);
	}
	return res;
}

int scanSymlink(HANDLE hParentDir, obj_entry_t *obj)
{
	int res = 0;
	NTSTATUS status = STATUS_SUCCESS;
	HANDLE hSymLink = NULL;
	UNICODE_STRING usSymLinkName = { 0 };
	UNICODE_STRING usSymLinkTarget = { 0 };
	ULONG ulTargetLen = 0;
	OBJECT_ATTRIBUTES symLinkAttr = { 0 };

	usSymLinkTarget.Length = usSymLinkTarget.MaximumLength = 0;
	pRtlInitUnicodeString(&usSymLinkName, obj->pwszName);
	InitializeObjectAttributes(&symLinkAttr, &usSymLinkName, 0, hParentDir, NULL);
	status = pNtOpenSymbolicLinkObject(&hSymLink, GENERIC_READ, &symLinkAttr);
	if (NT_ERROR(status))
	{
		res = status;
		fprintf(stderr, " [!] NtOpenSymbolicLinkObject(%S): code 0x%lX", obj->pwszName, res);
		if (status == STATUS_OBJECT_TYPE_MISMATCH)
			fprintf(stderr, " (not a symbolic link, or global symlink)");
		else if (status == STATUS_ACCESS_DENIED)
			fprintf(stderr, " (access denied)");
		fprintf(stderr, "\n");
		goto cleanup;
	}

	status = pNtQuerySymbolicLinkObject(hSymLink, &usSymLinkTarget, &ulTargetLen);
	if (status != STATUS_BUFFER_TOO_SMALL || ulTargetLen == 0 || ulTargetLen >= USHRT_MAX)
	{
		res = (status == STATUS_SUCCESS ? -1 : status);
		fprintf(stderr, " [!] NtQuerySymbolicLinkObject(): code %ld\n", res);
		goto cleanup;
	}

	usSymLinkTarget.Buffer = safe_alloc(ulTargetLen);
	usSymLinkTarget.Length = 0;
	usSymLinkTarget.MaximumLength = (USHORT)ulTargetLen;

	status = pNtQuerySymbolicLinkObject(hSymLink, &usSymLinkTarget, &ulTargetLen);
	if (NT_ERROR(status))
	{
		res = status;
		fprintf(stderr, " [!] NtQuerySymbolicLinkObject(): code 0x%lX\n", res);
		goto cleanup;
	}

	ulTargetLen = usSymLinkTarget.Length + sizeof(wchar_t);
	obj->pwszSymlinkTarget = safe_alloc(ulTargetLen);
	wcsncpy_s(obj->pwszSymlinkTarget, ulTargetLen / 2, usSymLinkTarget.Buffer, ulTargetLen / 2 - 1);

cleanup:
	CloseHandle(hSymLink);
	return res;
}

int scanDirectory(HANDLE hParentDir, PCWSTR pcwDirname, obj_entry_t **parentObj, BOOL bRecurse)
{
	int res = 0;
	UNICODE_STRING usObjName = { 0 };
	OBJECT_ATTRIBUTES objAttr = { 0 };
	NTSTATUS status = STATUS_SUCCESS;
	HANDLE hObjDir = NULL;
	ULONG ulQueryContext = 0;
	SIZE_T objInfoSize = 0x1000;
	POBJECT_DIRECTORY_INFORMATION pObjInfo = safe_alloc(objInfoSize);

	if (pcwDirname == NULL || parentObj == NULL || *parentObj == NULL)
		return EINVAL;

	if ((*parentObj)->pwszName == NULL)
	{
		(*parentObj)->pwszName = safe_alloc((wcslen(pcwDirname) + 1) * sizeof(wchar_t));
		wcscpy_s((*parentObj)->pwszName, wcslen(pcwDirname) + 1, pcwDirname);
	}
	if ((*parentObj)->pwszTypeName == NULL)
	{
		(*parentObj)->pwszTypeName = safe_alloc((wcslen(L"Directory") + 1) * sizeof(wchar_t));
		wcscpy_s((*parentObj)->pwszTypeName, wcslen(L"Directory") + 1, L"Directory");
	}

	pRtlInitUnicodeString(&usObjName, pcwDirname);
	InitializeObjectAttributes(&objAttr, &usObjName, 0, hParentDir, NULL);

	status = pNtOpenDirectoryObject(&hObjDir, DIRECTORY_QUERY | DIRECTORY_TRAVERSE, &objAttr);
	if (NT_ERROR(status))
	{
		res = status;
		fprintf(stderr, " [!] NtOpenDirectoryObject(%S): code 0x%lX", pcwDirname, res);
		if (status == STATUS_OBJECT_TYPE_MISMATCH)
			fprintf(stderr, " (not a directory)");
		else if (status == STATUS_ACCESS_DENIED)
			fprintf(stderr, " (access denied)");
		fprintf(stderr, "\n");
		goto cleanup;
	}

	while (1)
	{
		ZeroMemory(pObjInfo, objInfoSize);
		status = pNtQueryDirectoryObject(hObjDir, pObjInfo, (ULONG)objInfoSize, TRUE, FALSE, &ulQueryContext, NULL);
		if (status == STATUS_BUFFER_TOO_SMALL)
		{
			objInfoSize *= 2;
			pObjInfo = safe_realloc(pObjInfo, objInfoSize);
			continue;
		}
		else if (NT_ERROR(status))
		{
			res = status;
			fprintf(stderr, " [!] NtQueryDirectoryObject(): code 0x%lX\n", res);
			goto cleanup;
		}
		else if (pObjInfo->TypeName.Length == 0 || pObjInfo->Name.Length == 0)
		{
			break;
		}

		obj_entry_t *childObj = safe_alloc(sizeof(obj_entry_t));
		childObj->entrySize = sizeof(obj_entry_t);

		childObj->pwszName = safe_alloc(pObjInfo->Name.Length + sizeof(wchar_t));
		childObj->pwszTypeName = safe_alloc(pObjInfo->TypeName.Length + sizeof(wchar_t));
		wcscpy_s(childObj->pwszName, pObjInfo->Name.Length / 2 + sizeof(wchar_t), pObjInfo->Name.Buffer);
		wcscpy_s(childObj->pwszTypeName, pObjInfo->TypeName.Length / 2 + sizeof(wchar_t), pObjInfo->TypeName.Buffer);

		if (_wcsicmp(childObj->pwszTypeName, L"Directory") == 0 && bRecurse)
		{
			res = scanDirectory(hObjDir, childObj->pwszName, &childObj, bRecurse);
			if (res != 0)
			{
				fprintf(stderr, " [!] Failed to scan subdirectory %S (code %ld)\n", childObj->pwszName, res);
			}
		}
		else if (_wcsicmp(childObj->pwszTypeName, L"SymbolicLink") == 0)
		{
			res = scanSymlink(hObjDir, childObj);
		}

		*parentObj = safe_realloc(*parentObj, (*parentObj)->entrySize + sizeof(void*));
		(*parentObj)->entrySize += sizeof(void*);
		(*parentObj)->pChildObj[(*parentObj)->childObjCount] = childObj;
		(*parentObj)->childObjCount++;
	}

	sort_child_objects_by(*parentObj, &cmp_obj_names);

cleanup:
	if (hObjDir != NULL)
		CloseHandle(hObjDir);
	return res;
}

void printEntry(obj_entry_t *obj, int depth)
{
	wprintf(L"%20s  ", obj->pwszTypeName);
	for (int i = 0; i < depth - 1; i++)
	    printf("|  ");
	if (depth > 0)
		printf("+- ");
	printf("%S", obj->pwszName);
	if (_wcsicmp(obj->pwszTypeName, L"SymbolicLink") == 0)
	{
		printf(" -> %S", (obj->pwszSymlinkTarget == NULL ? L"(unknown)" : obj->pwszSymlinkTarget));
	}
	printf("\n");
	for (SIZE_T i = 0; i < obj->childObjCount; i++)
		printEntry(obj->pChildObj[i], depth + 1);
}

void printDirectory(obj_entry_t *objDir)
{
	printEntry(objDir, 0);
}

int wmain(int argc, wchar_t *argv[])
{
	int res = 0;
	HANDLE hNtdll = NULL;
	PWSTR pwzTarget = L"";
	SIZE_T targetLen = 0;
	BOOL bRecurse = FALSE;
	obj_entry_t *rootObj = NULL;

	hNtdll = GetModuleHandleA("ntdll.dll");
	if (hNtdll == NULL)
	{
		res = GetLastError();
		fprintf(stderr, " [!] GetModuleHandle(): code %ld\n", res);
		goto cleanup;
	}
	
	pRtlInitUnicodeString = (_RtlInitUnicodeString)GetProcAddress(hNtdll, "RtlInitUnicodeString");
	if (pRtlInitUnicodeString == NULL)
	{
		res = GetLastError();
		fprintf(stderr, " [!] GetProcAddress(ntdll, RtlInitUnicodeString): code %ld\n", res);
		goto cleanup;
	}

	pNtOpenDirectoryObject = (_NtOpenDirectoryObject)GetProcAddress(hNtdll, "NtOpenDirectoryObject");
	if (pNtOpenDirectoryObject == NULL)
	{
		res = GetLastError();
		fprintf(stderr, " [!] GetProcAddress(ntdll, NtOpenDirectoryObject): code %ld\n", res);
		goto cleanup;
	}

	pNtQueryDirectoryObject = (_NtQueryDirectoryObject)GetProcAddress(hNtdll, "NtQueryDirectoryObject");
	if (pNtQueryDirectoryObject == NULL)
	{
		res = GetLastError();
		fprintf(stderr, " [!] GetProcAddress(ntdll, NtQueryDirectoryObject): code %ld\n", res);
		goto cleanup;
	}

	pNtOpenSymbolicLinkObject = (_NtOpenSymbolicLinkObject)GetProcAddress(hNtdll, "NtOpenSymbolicLinkObject");
	if (pNtOpenSymbolicLinkObject == NULL)
	{
		res = GetLastError();
		fprintf(stderr, " [!] GetProcAddress(ntdll, NtOpenSymbolicLinkObject): code %ld\n", res);
		goto cleanup;
	}

	pNtQuerySymbolicLinkObject = (_NtQuerySymbolicLinkObject)GetProcAddress(hNtdll, "NtQuerySymbolicLinkObject");
	if (pNtQuerySymbolicLinkObject == NULL)
	{
		res = GetLastError();
		fprintf(stderr, " [!] GetProcAddress(ntdll, NtQuerySymbolicLinkObject): code %ld\n", res);
		goto cleanup;
	}

	if (argc >= 2 && _wcsicmp(argv[1], L"-H") == 0)
	{
		print_help();
		return 0;
	}
	else if (argc >= 2 && _wcsicmp(argv[1], L"-R") == 0)
	{
		bRecurse = TRUE;
		argc--;
		argv[1] = argv[0];
		argv++;
	}
	else if (argc >= 2 && argv[1][0] == L'-')
	{
		fprintf(stderr, "Error: unknown option %S\n", argv[1]);
		print_help();
		return 1;
	}

	if (argc > 2)
	{
		fprintf(stderr, "Error: too many arguments\n");
		print_help();
		return 1;
	}
	
	if (argc == 2)
		pwzTarget = argv[1];

	targetLen = wcslen(pwzTarget);
	if (targetLen == 0)
		pwzTarget = L"\\";
	else if (targetLen > 1 && pwzTarget[targetLen - 1] == L'\\')
		pwzTarget[targetLen - 1] = L'\0';

	rootObj = safe_alloc(sizeof(*rootObj));
	rootObj->entrySize = sizeof(*rootObj);
	
	res = scanDirectory(NULL, pwzTarget, &rootObj, bRecurse);

	printDirectory(rootObj);

cleanup:
	return res;
}