FwpmFilterAdd0 function (fwpmk.h)

Artikel
07/12/2024

The FwpmFilterAdd0 function adds a new filter object to the system.

Syntax

NTSTATUS FwpmFilterAdd0(
  [in]            HANDLE               engineHandle,
  [in]            const FWPM_FILTER0   *filter,
  [in, optional]  PSECURITY_DESCRIPTOR sd,
  [out, optional] UINT64               *id
);

Parameters

[in] engineHandle

Handle for an open session to the filter engine. Call FwpmEngineOpen0 to open a session to the filter engine.

[in] filter

The filter object to be added.

[in, optional] sd

Security information about the filter object.

[out, optional] id

The runtime identifier for this filter.

Return value

Return code/value	Description
ERROR_SUCCESS 0	The filter was successfully added.
ERROR_INVALID_SECURITY_DESCR 0x8007053A	The security descriptor structure is invalid. Or, a filter condition contains a security descriptor in absolute format.
FWP_E_CALLOUT_NOTIFICATION_FAILED 0x80320037	The caller added a callout filter and the callout returned an error from its notification routine.
FWP_E_* error code 0x80320001—0x80320039	A Windows Filtering Platform (WFP) specific error. See WFP Error Codes for details.
RPC_* error code 0x80010001—0x80010122	Failure to communicate with the remote or local firewall engine.
Other NTSTATUS codes	An error occurred.

Remarks

FwpmFilterAdd0 adds the filter to the specified sub-layer at every filtering layer in the system.

Some fields in the FWPM_FILTER0 structure are assigned by the system, not the caller, and are ignored in the call to FwpmFilterAdd0.

If the caller supplies a NULL security descriptor, the system will assign a default security descriptor.

To block connections to particular locations, add a FWP_ACTION_BLOCK filter specifying the local address at the FWPM_LAYER_ALE_AUTH_CONNECT_V* layer, or add a FWP_ACTION_BLOCK filter without specifying the local address at the FWPM_LAYER_ALE_RESOURCE_ASSIGNMENT_V* layer.

If a local address is specified at the resource assignment layer, an implicit bind would succeed because address, address type, and port may come back as FWP_EMPTY.

The FWPM_FILTER0 structure can label a filter as a boot-time or persistent filter. Boot-time filters are added to the Base Filtering Engine (BFE) when the TCP/IP driver starts, and are removed once the BFE finishes initialization. Persistent objects are added when the BFE starts.

This function cannot be called from within a read-only transaction, it fails with FWP_E_INCOMPATIBLE_TXN. See Object Management for more information about transactions.

The caller needs the following access rights:

FWPM_ACTRL_ADD access to the filter's container
FWPM_ACTRL_ADD_LINK access to the provider (if any)
FWPM_ACTRL_ADD_LINK access to the applicable layer
FWPM_ACTRL_ADD_LINK access to the applicable sub-layer
FWPM_ACTRL_ADD_LINK access to the callout (if any)
FWPM_ACTRL_ADD_LINK access to the provider context (if any).

See Access Control for more information.

To add a filter that references a callout, invoke the functions in the following order.

Call FwpsCalloutRegister0 (documented in the Windows Driver Kit (WDK)), to register the callout with the filter engine.
Call FwpmCalloutAdd0 to add the callout to the system.
Call FwpmFilterAdd0 to add the filter that references the callout to the system.

By default filters that reference callouts that have been added but have not yet registered with the filter engine are treated as Block filters.

FwpmFilterAdd0 is a specific implementation of FwpmFilterAdd. See WFP Version-Independent Names and Targeting Specific Versions of Windows for more information.

Examples

The following C++ example shows how to initialize and add a filter using FwpmFilterAdd0 that specifically blocks traffic on IP V4 for all applications.

// Add filter to block traffic on IP V4 for all applications. 
//
FWPM_FILTER0      fwpFilter;
FWPM_SUBLAYER0    fwpFilterSubLayer;  

RtlZeroMemory(&fwpFilter, sizeof(FWPM_FILTER0));

fwpFilter.layerKey = FWPM_LAYER_ALE_AUTH_RECV_ACCEPT_V4;
fwpFilter.action.type = FWP_ACTION_BLOCK;

if (&fwpFilterSubLayer.subLayerKey != NULL)
    fwpFilter.subLayerKey = fwpFilterSubLayer.subLayerKey;

fwpFilter.weight.type = FWP_EMPTY; // auto-weight.
fwpFilter.numFilterConditions = 0; // this applies to all application traffic
fwpFilter.displayData.name = L"Receive/Accept Layer Block";
fwpFilter.displayData.description = L"Filter to block all inbound connections.";

printf("Adding filter to block all inbound connections.\n");
result = FwpmFilterAdd0(engineHandle, &fwpFilter, NULL, NULL);

if (result != ERROR_SUCCESS)
    printf("FwpmFilterAdd0 failed. Return value: %d.\n", result);
else
    printf("Filter added successfully.\n");

Requirements

Requirement	Value
Minimum supported client	Available starting with Windows Vista.
Target Platform	Universal
Header	fwpmk.h
Library	fwpkclnt.lib
IRQL	<= PASSIVE_LEVEL

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