[NTOS:PNP]

Fix IopGetParentIdPrefix:
- Do not include null terminator in UNICODE_STRING::Length
- Use pool tagging
- Use strsafe printf
- Avoid a magic number

svn path=/trunk/; revision=74049
This commit is contained in:
Thomas Faber 2017-03-04 13:50:55 +00:00
parent 54688094ac
commit 4c03c1a55a

View file

@ -1634,6 +1634,7 @@ NTSTATUS
IopGetParentIdPrefix(PDEVICE_NODE DeviceNode,
PUNICODE_STRING ParentIdPrefix)
{
const UNICODE_STRING EnumKeyPath = RTL_CONSTANT_STRING(L"\\Registry\\Machine\\System\\CurrentControlSet\\Enum\\");
ULONG KeyNameBufferLength;
PKEY_VALUE_PARTIAL_INFORMATION ParentIdPrefixInformation = NULL;
UNICODE_STRING KeyName = {0, 0, NULL};
@ -1655,22 +1656,28 @@ IopGetParentIdPrefix(PDEVICE_NODE DeviceNode,
/* 1. Try to retrieve ParentIdPrefix from registry */
KeyNameBufferLength = FIELD_OFFSET(KEY_VALUE_PARTIAL_INFORMATION, Data[0]) + MAX_PATH * sizeof(WCHAR);
ParentIdPrefixInformation = ExAllocatePool(PagedPool, KeyNameBufferLength + sizeof(WCHAR));
ParentIdPrefixInformation = ExAllocatePoolWithTag(PagedPool,
KeyNameBufferLength + sizeof(UNICODE_NULL),
TAG_IO);
if (!ParentIdPrefixInformation)
{
return STATUS_INSUFFICIENT_RESOURCES;
}
KeyName.Buffer = ExAllocatePool(PagedPool, (49 * sizeof(WCHAR)) + DeviceNode->Parent->InstancePath.Length);
KeyName.Length = 0;
KeyName.MaximumLength = EnumKeyPath.Length +
DeviceNode->Parent->InstancePath.Length +
sizeof(UNICODE_NULL);
KeyName.Buffer = ExAllocatePoolWithTag(PagedPool,
KeyName.MaximumLength,
TAG_IO);
if (!KeyName.Buffer)
{
Status = STATUS_INSUFFICIENT_RESOURCES;
goto cleanup;
}
KeyName.Length = 0;
KeyName.MaximumLength = (49 * sizeof(WCHAR)) + DeviceNode->Parent->InstancePath.Length;
RtlAppendUnicodeToString(&KeyName, L"\\Registry\\Machine\\System\\CurrentControlSet\\Enum\\");
RtlCopyUnicodeString(&KeyName, &EnumKeyPath);
RtlAppendUnicodeStringToString(&KeyName, &DeviceNode->Parent->InstancePath);
Status = IopOpenRegistryKeyEx(&hKey, NULL, &KeyName, KEY_QUERY_VALUE | KEY_SET_VALUE);
@ -1693,15 +1700,20 @@ IopGetParentIdPrefix(PDEVICE_NODE DeviceNode,
}
else
{
KeyValue.Length = KeyValue.MaximumLength = (USHORT)ParentIdPrefixInformation->DataLength;
KeyValue.MaximumLength = (USHORT)ParentIdPrefixInformation->DataLength;
KeyValue.Length = KeyValue.MaximumLength - sizeof(UNICODE_NULL);
KeyValue.Buffer = (PWSTR)ParentIdPrefixInformation->Data;
ASSERT(KeyValue.Buffer[KeyValue.Length / sizeof(WCHAR)] == UNICODE_NULL);
}
goto cleanup;
}
if (Status != STATUS_OBJECT_NAME_NOT_FOUND)
{
KeyValue.Length = KeyValue.MaximumLength = (USHORT)ParentIdPrefixInformation->DataLength;
/* FIXME how do we get here and why is ParentIdPrefixInformation valid? */
KeyValue.MaximumLength = (USHORT)ParentIdPrefixInformation->DataLength;
KeyValue.Length = KeyValue.MaximumLength - sizeof(UNICODE_NULL);
KeyValue.Buffer = (PWSTR)ParentIdPrefixInformation->Data;
ASSERT(KeyValue.Buffer[KeyValue.Length / sizeof(WCHAR)] == UNICODE_NULL);
goto cleanup;
}
@ -1710,8 +1722,12 @@ IopGetParentIdPrefix(PDEVICE_NODE DeviceNode,
(PUCHAR)DeviceNode->Parent->InstancePath.Buffer,
DeviceNode->Parent->InstancePath.Length);
swprintf((PWSTR)ParentIdPrefixInformation->Data, L"%lx&%lx", DeviceNode->Parent->Level, crc32);
RtlInitUnicodeString(&KeyValue, (PWSTR)ParentIdPrefixInformation->Data);
RtlStringCbPrintfW((PWSTR)ParentIdPrefixInformation,
KeyNameBufferLength,
L"%lx&%lx",
DeviceNode->Parent->Level,
crc32);
RtlInitUnicodeString(&KeyValue, (PWSTR)ParentIdPrefixInformation);
/* 3. Try to write the ParentIdPrefix to registry */
Status = ZwSetValueKey(hKey,
@ -1729,7 +1745,7 @@ cleanup:
&KeyValue,
ParentIdPrefix);
}
ExFreePool(ParentIdPrefixInformation);
ExFreePoolWithTag(ParentIdPrefixInformation, TAG_IO);
RtlFreeUnicodeString(&KeyName);
if (hKey != NULL)
{