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Update misleading informations in NtNotifyChangeMultipleKeys #2008

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Karl-Bridge-Microsoft merged 2 commits into from
Apr 30, 2025
Merged

Update misleading informations in NtNotifyChangeMultipleKeys #2008

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2b4e062
Update nf-winternl-ntnotifychangemultiplekeys.md
xmine64 Apr 30, 2025
c8c6397
Update nf-winternl-ntnotifychangemultiplekeys.md
Karl-Bridge-Microsoft Apr 30, 2025
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12 changes: 6 additions & 6 deletions sdk-api-src/content/winternl/nf-winternl-ntnotifychangemultiplekeys.md
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Expand Up @@ -6,7 +6,7 @@ helpviewer_keywords: ["NtNotifyChangeMultipleKeys","NtNotifyChangeMultipleKeys f
old-location: winprog\ntnotifychangemultiplekeys.htm
tech.root: winprog
ms.assetid: c1ee9793-490c-45de-a2a5-deab630917f6
ms.date: 12/05/2018
ms.date: 04/30/2025
ms.keywords: NtNotifyChangeMultipleKeys, NtNotifyChangeMultipleKeys function [Windows API], REG_NOTIFY_CHANGE_ATTRIBUTES, REG_NOTIFY_CHANGE_LAST_SET, REG_NOTIFY_CHANGE_NAME, REG_NOTIFY_CHANGE_SECURITY, base.ntnotifychangemultiplekeys, winprog.ntnotifychangemultiplekeys, winternl/NtNotifyChangeMultipleKeys
req.header: winternl.h
req.include-header:
Expand Down Expand Up @@ -62,23 +62,23 @@ A handle to an open key. The handle must be opened with the <b>KEY_NOTIFY</b> ac

### -param Count [in, optional]

The number of subkeys under the key specified by the <i>MasterKeyHandle</i> parameter. This parameter must be 1.
The number of keys objects provided in the <i>SubordinateObjects</i> parameter. This parameter must be 1.

### -param SubordinateObjects [in, optional]

Pointer to an array of <a href="/windows-hardware/drivers/ddi/content/wudfwdm/ns-wudfwdm-_object_attributes">OBJECT_ATTRIBUTES</a> structures, one for each subkey. This array can contain one <b>OBJECT_ATTRIBUTES</b> structure.
Pointer to an array of <a href="/windows-hardware/drivers/ddi/content/wudfwdm/ns-wudfwdm-_object_attributes">OBJECT_ATTRIBUTES</a> structures, one for each key. This array can contain one <b>OBJECT_ATTRIBUTES</b> structure and must not be a key in the same hive as the <i>MasterKeyHandle</i> key.
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@HBelusca HBelusca May 1, 2025

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If these aren't in the same hive as the master root key, how then could they be "subkeys" of a given registry key, as the summary description of this function claims they are?
What then would be the usefulness of the function altogether if this weren't the case?

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@xmine64 xmine64 May 1, 2025

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Being a subkey isn't a requirement, I tested the API on \Registry\User.Default\TestKey while the master key was \Registry\Machine\Software\TestKey and it worked. While being a subkey is not a requirement, it's possible to load a hive in a non-root key so that way a key would have a subkey from another hive. As far as I know that's how BCD and SAM database are loaded in to the registry, they're not a root key like HKLM but a subkey of a parent key, but they're from a separate hive compared to their parent.


### -param Event [in, optional]

A handle to an event created by the caller. If <i>Event</i> is not <b>NULL</b>, the caller waits until the operation succeeds, at which time the event is signaled.

### -param ApcRoutine [in, optional]

A pointer to an asynchronous procedure call (APC) function supplied by the caller. If <i>ApcRoutine</i> is not <b>NULL</b>, the specified APC function executes after the operation completes.
A pointer to an asynchronous procedure call (APC) function supplied by the caller. If <i>ApcRoutine</i> is not <b>NULL</b>, the specified APC function executes after the operation completes. A <a href="/windows-hardware/drivers/ddi/wdm/ns-wdm-_work_queue_item">WORK_QUEUE_ITEM</a> must be provided instead of ApcRoutine in the <i>ZwNotifyChangeMultipleKeys</i> variant.
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@HBelusca HBelusca May 1, 2025

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The proposed change is strange. Normally zw routines are == NT ones except for the detour back into the syscall table that changes the PreviousMode to KerneMode.
(When being invoked from user-mode via ntdll, both are the same thing.)
Are you suggesting that the parameter purpose completely changes altogether?

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@xmine64 xmine64 May 1, 2025

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The said parameters are just pointers, and they can be treated differently. This behavior was documented in ZwNotifyChangeKey but not here.


### -param ApcContext [in, optional]

A pointer to a context supplied by the caller for its APC function. This value is passed to the APC function when it is executed. The <i>Asynchronous</i> parameter must be <b>TRUE</b>. If <i>ApcContext</i> is specified, the <i>Event</i> parameter must be <b>NULL</b>.
A pointer to a context supplied by the caller for its APC function. This value is passed to the APC function when it is executed. The <i>Asynchronous</i> parameter must be <b>TRUE</b>. If <i>ApcContext</i> is specified, the <i>Event</i> parameter must be <b>NULL</b>. A <a href="/windows-hardware/drivers/ddi/wdm/ne-wdm-_work_queue_type">WORK_QUEUE_TYPE</a> must be provided instead of ApcContext in the <i>ZwNotifyChangeMultipleKeys</i> variant.

### -param IoStatusBlock [out]

Expand Down Expand Up @@ -165,4 +165,4 @@ This function has no associated header file. You can also use the <a href="/wind

## -see-also

<a href="/windows/desktop/SysInfo/registry-key-security-and-access-rights">Registry Key Security and Access Rights</a>
<a href="/windows/desktop/SysInfo/registry-key-security-and-access-rights">Registry Key Security and Access Rights</a>