mirror of
https://github.com/reactos/reactos.git
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0f9be53985
And remove the "!NT_SUCCESS(Status)" check which is excessive, the expected status will always be STATUS_BUFFER_TOO_SMALL anyway. This should fix some compilation warnings spotted by GCC. Courtesy goes to Hermes for letting me know of these warnings.
565 lines
18 KiB
C
565 lines
18 KiB
C
/*
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* PROJECT: ReactOS Win32k subsystem
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* LICENSE: GPL-2.0-or-later (https://spdx.org/licenses/GPL-2.0-or-later)
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* PURPOSE: Security infrastructure of NTUSER component of Win32k
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* COPYRIGHT: Copyright 2022-2023 George Bișoc <george.bisoc@reactos.org>
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*/
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/* INCLUDES ******************************************************************/
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#include <win32k.h>
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DBG_DEFAULT_CHANNEL(UserSecurity);
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/* FUNCTIONS *****************************************************************/
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/**
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* @brief
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* Opens an access token that represents the effective security
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* context of the caller. The purpose of this function is to query
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* the authenticated user that is associated with the security
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* context.
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*
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* @return
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* Returns a handle to an opened access token that represents the
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* security context of the authenticated user, otherwise NULL.
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*/
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HANDLE
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IntGetCurrentAccessToken(VOID)
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{
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NTSTATUS Status;
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HANDLE TokenHandle;
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/*
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* Try acquiring the security context by opening
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* the current thread (or so called impersonation)
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* token. Such token represents the effective caller.
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* Otherwise if the current thread does not have a
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* token (hence no impersonation occurs) then open
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* the token of main calling process instead.
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*/
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Status = ZwOpenThreadToken(ZwCurrentThread(),
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TOKEN_QUERY,
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FALSE,
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&TokenHandle);
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if (!NT_SUCCESS(Status))
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{
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/*
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* We might likely fail to open the thread
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* token if the process isn't impersonating
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* a client. In scenarios where the server
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* isn't impersonating, open the main process
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* token.
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*/
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if (Status == STATUS_NO_TOKEN)
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{
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TRACE("IntGetCurrentAccessToken(): The thread doesn't have a token, trying to open the process one...\n");
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Status = ZwOpenProcessToken(ZwCurrentProcess(),
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TOKEN_QUERY,
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&TokenHandle);
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if (!NT_SUCCESS(Status))
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{
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/* We failed opening process token as well, bail out... */
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ERR("IntGetCurrentAccessToken(): Failed to capture security context, couldn't open the process token (Status 0x%08lx)\n", Status);
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return NULL;
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}
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/* Return the opened token handle */
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return TokenHandle;
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}
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/* There's a thread token but we couldn't open it so bail out */
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ERR("IntGetCurrentAccessToken(): Failed to capture security context, couldn't open the thread token (Status 0x%08lx)\n", Status);
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return NULL;
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}
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/* Return the opened token handle */
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return TokenHandle;
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}
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/**
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* @brief
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* Allocates a buffer within UM (user mode) address
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* space area. Such buffer is reserved for security
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* purposes, such as allocating a buffer for a DACL
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* or a security descriptor.
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*
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* @param[in] Length
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* The length of the buffer that has to be allocated,
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* in bytes.
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*
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* @return
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* Returns a pointer to an allocated buffer whose
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* contents are arbitrary. If the function fails,
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* it means no pages are available to reserve for
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* memory allocation for this buffer.
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*/
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PVOID
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IntAllocateSecurityBuffer(
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_In_ SIZE_T Length)
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{
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NTSTATUS Status;
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PVOID Buffer = NULL;
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/* Allocate the buffer in UM memory space */
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Status = ZwAllocateVirtualMemory(ZwCurrentProcess(),
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&Buffer,
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0,
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&Length,
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MEM_COMMIT,
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PAGE_READWRITE);
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if (!NT_SUCCESS(Status))
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{
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ERR("IntAllocateSecurityBuffer(): Failed to allocate the buffer (Status 0x%08lx)\n", Status);
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return NULL;
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}
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return Buffer;
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}
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/**
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* @brief
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* Frees an allocated security buffer from UM
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* memory that is been previously allocated by
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* IntAllocateSecurityBuffer function.
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*
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* @param[in] Buffer
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* A pointer to a buffer whose contents are
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* arbitrary, to be freed from UM memory space.
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*
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* @return
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* Nothing.
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*/
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VOID
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IntFreeSecurityBuffer(
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_In_ PVOID Buffer)
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{
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SIZE_T Size = 0;
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ZwFreeVirtualMemory(ZwCurrentProcess(),
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&Buffer,
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&Size,
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MEM_RELEASE);
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}
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/**
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* @brief
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* Queries the authenticated user security identifier
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* (SID) that is associated with the security context
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* of the access token that is being opened.
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*
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* @param[out] User
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* A pointer to the token user that contains the security
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* identifier of the authenticated user.
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*
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* @return
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* Returns STATUS_SUCCESS if the function has successfully
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* queried the token user. STATUS_UNSUCCESSFUL is returned
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* if the effective token of the caller couldn't be opened.
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* STATUS_NO_MEMORY is returned if memory allocation for
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* token user buffer has failed because of lack of necessary
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* pages reserved for such allocation. A failure NTSTATUS
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* code is returned otherwise.
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*
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* @remarks
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* !!!WARNING!!! -- THE CALLER WHO QUERIES THE TOKEN USER IS
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* RESPONSIBLE TO FREE THE ALLOCATED TOKEN USER BUFFER THAT IS
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* BEING GIVEN.
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*/
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NTSTATUS
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IntQueryUserSecurityIdentification(
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_Out_ PTOKEN_USER *User)
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{
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NTSTATUS Status;
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PTOKEN_USER UserToken = NULL;
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HANDLE Token;
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ULONG BufferLength;
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/* Initialize the parameter */
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*User = NULL;
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/* Open the current token of the caller */
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Token = IntGetCurrentAccessToken();
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if (!Token)
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{
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ERR("IntQueryUserSecurityIdentification(): Couldn't capture the token!\n");
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return STATUS_UNSUCCESSFUL;
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}
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/*
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* Since we do not know what the length
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* of the buffer size should be exactly to
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* hold the user data, let the function
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* tell us the size.
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*/
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Status = ZwQueryInformationToken(Token,
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TokenUser,
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NULL,
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0,
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&BufferLength);
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if (Status == STATUS_BUFFER_TOO_SMALL)
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{
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/*
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* Allocate some memory for the buffer
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* based on the size that the function
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* gave us.
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*/
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UserToken = IntAllocateSecurityBuffer(BufferLength);
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if (!UserToken)
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{
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/* Bail out if we failed */
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ERR("IntQueryUserSecurityIdentification(): Couldn't allocate memory for the token user!\n");
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ZwClose(Token);
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return STATUS_NO_MEMORY;
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}
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}
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else if (!NT_SUCCESS(Status))
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{
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ERR("IntQueryUserSecurityIdentification(): Failed to query the necessary length for the buffer (Status 0x%08lx)!\n", Status);
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ZwClose(Token);
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return Status;
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}
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/* Query the user now as we have plenty of space to hold it */
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Status = ZwQueryInformationToken(Token,
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TokenUser,
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UserToken,
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BufferLength,
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&BufferLength);
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if (!NT_SUCCESS(Status))
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{
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/* We failed, bail out */
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ERR("IntQueryUserSecurityIdentification(): Failed to query token user (Status 0x%08lx)\n", Status);
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IntFreeSecurityBuffer(UserToken);
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ZwClose(Token);
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return Status;
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}
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/* All good, give the buffer to the caller and close the captured token */
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*User = UserToken;
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ZwClose(Token);
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return STATUS_SUCCESS;
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}
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/**
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* @brief
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* Assigns a security descriptor to the desktop
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* object during a desktop object parse procedure.
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*
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* @param[in] WinSta
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* A pointer to a window station object, of which
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* such object contains its own security descriptor
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* that will be captured.
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*
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* @param[in] Desktop
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* A pointer to a desktop object that is created
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* during a parse procedure.
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*
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* @param[in] AccessState
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* A pointer to an access state structure that
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* describes the progress state of an access in
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* action.
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*
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* @return
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* Returns STATUS_SUCCESS if the function has successfully
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* assigned new security descriptor to the desktop object.
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* A NTSTATUS failure code is returned otherwise.
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*/
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NTSTATUS
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NTAPI
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IntAssignDesktopSecurityOnParse(
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_In_ PWINSTATION_OBJECT WinSta,
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_In_ PDESKTOP Desktop,
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_In_ PACCESS_STATE AccessState)
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{
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NTSTATUS Status;
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PSECURITY_DESCRIPTOR CapturedDescriptor;
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BOOLEAN MemoryAllocated;
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/*
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* Capture the security descriptor from
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* the window station. The window station
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* in question has a descriptor that is
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* inheritable and contains desktop access
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* rights as well.
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*/
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Status = ObGetObjectSecurity(WinSta,
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&CapturedDescriptor,
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&MemoryAllocated);
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if (!NT_SUCCESS(Status))
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{
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ERR("IntAssignDesktopSecurityOnParse(): Failed to capture the security descriptor from window station (Status 0x%08lx)\n", Status);
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return Status;
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}
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/* Assign new security to the desktop */
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Status = ObAssignSecurity(AccessState,
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CapturedDescriptor,
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Desktop,
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ExDesktopObjectType);
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if (!NT_SUCCESS(Status))
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{
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ERR("IntAssignDesktopSecurityOnParse(): Failed to assign security information to the desktop object (Status 0x%08lx)\n", Status);
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}
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/* Release the descriptor that we have captured */
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ObReleaseObjectSecurity(CapturedDescriptor, MemoryAllocated);
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return Status;
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}
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/**
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* @brief
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* Creates a security descriptor for the service.
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*
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* @param[out] ServiceSd
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* A pointer to a newly allocated and created security
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* descriptor for the service.
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*
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* @return
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* Returns STATUS_SUCCESS if the function has successfully
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* queried created the security descriptor. STATUS_NO_MEMORY
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* is returned if memory allocation for security buffers because
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* of a lack of needed pages to reserve for such allocation. A
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* failure NTSTATUS code is returned otherwise.
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*/
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NTSTATUS
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NTAPI
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IntCreateServiceSecurity(
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_Out_ PSECURITY_DESCRIPTOR *ServiceSd)
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{
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NTSTATUS Status;
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PACL ServiceDacl;
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ULONG DaclSize;
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ULONG RelSDSize;
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SECURITY_DESCRIPTOR AbsSD;
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PSECURITY_DESCRIPTOR RelSD;
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PTOKEN_USER TokenUser;
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/* Initialize our local variables */
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RelSDSize = 0;
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TokenUser = NULL;
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RelSD = NULL;
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ServiceDacl = NULL;
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/* Query the logged in user of the current security context (aka token) */
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Status = IntQueryUserSecurityIdentification(&TokenUser);
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if (!TokenUser)
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{
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ERR("IntCreateServiceSecurity(): Failed to query the token user (Status 0x%08lx)\n", Status);
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return Status;
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}
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/* Initialize the absolute security descriptor */
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Status = RtlCreateSecurityDescriptor(&AbsSD, SECURITY_DESCRIPTOR_REVISION);
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if (!NT_SUCCESS(Status))
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{
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ERR("IntCreateServiceSecurity(): Failed to initialize absolute SD (Status 0x%08lx)\n", Status);
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goto Quit;
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}
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/*
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* Build up the size of access control
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* list (the DACL) necessary to initialize
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* our ACL. The first two entry members
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* of ACL field are the authenticated user
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* that is associated with the security
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* context of the token. Then here come
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* the last two entries which are admins.
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* Why the ACL contains two ACEs of the
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* same SID is because of service access
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* rights and ACE inheritance.
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*
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* A service is composed of a default
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* desktop and window station upon
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* booting the system. On Windows connection
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* to such service is being made if no
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* default window station and desktop handles
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* were created before. The desktop and winsta
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* objects grant access on a separate type basis.
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* The user is granted full access to the window
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* station first and then full access to the desktop.
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* After that admins are granted specific rights
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* separately, just like the user. Ultimately the
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* ACEs that handle desktop rights management are
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* inherited to the default desktop object so
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* that there's no need to have a separate security
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* descriptor for the desktop object alone.
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*/
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DaclSize = sizeof(ACL) +
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sizeof(ACCESS_ALLOWED_ACE) + RtlLengthSid(TokenUser->User.Sid) +
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sizeof(ACCESS_ALLOWED_ACE) + RtlLengthSid(TokenUser->User.Sid) +
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sizeof(ACCESS_ALLOWED_ACE) + RtlLengthSid(SeExports->SeAliasAdminsSid) +
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sizeof(ACCESS_ALLOWED_ACE) + RtlLengthSid(SeExports->SeAliasAdminsSid);
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/* Allocate memory for service DACL */
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ServiceDacl = IntAllocateSecurityBuffer(DaclSize);
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if (!ServiceDacl)
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{
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ERR("IntCreateServiceSecurity(): Failed to allocate memory for service DACL!\n");
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Status = STATUS_NO_MEMORY;
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goto Quit;
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}
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/* Now create the DACL */
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Status = RtlCreateAcl(ServiceDacl,
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DaclSize,
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ACL_REVISION);
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if (!NT_SUCCESS(Status))
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{
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ERR("IntCreateServiceSecurity(): Failed to create service DACL (Status 0x%08lx)\n", Status);
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goto Quit;
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}
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/*
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* The authenticated user is the ultimate and absolute
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* king in charge of the created (or opened, whatever that is)
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* window station object.
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*/
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Status = RtlAddAccessAllowedAceEx(ServiceDacl,
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ACL_REVISION,
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0,
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WINSTA_ACCESS_ALL,
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TokenUser->User.Sid);
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if (!NT_SUCCESS(Status))
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{
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ERR("IntCreateServiceSecurity(): Failed to set up window station ACE for authenticated user (Status 0x%08lx)\n", Status);
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goto Quit;
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}
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/*
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* The authenticated user also has the ultimate power
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* over the desktop object as well. This ACE cannot
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* be propagated but inherited. See the comment
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* above regarding ACL size for further explanation.
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*/
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Status = RtlAddAccessAllowedAceEx(ServiceDacl,
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ACL_REVISION,
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INHERIT_ONLY_ACE | NO_PROPAGATE_INHERIT_ACE | OBJECT_INHERIT_ACE,
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DESKTOP_ALL_ACCESS,
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TokenUser->User.Sid);
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if (!NT_SUCCESS(Status))
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{
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ERR("IntCreateServiceSecurity(): Failed to set up desktop ACE for authenticated user (Status 0x%08lx)\n", Status);
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goto Quit;
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}
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/*
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* Administrators can only enumerate window
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* stations within a desktop.
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*/
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Status = RtlAddAccessAllowedAceEx(ServiceDacl,
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ACL_REVISION,
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0,
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WINSTA_ENUMERATE,
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SeExports->SeAliasAdminsSid);
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if (!NT_SUCCESS(Status))
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{
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ERR("IntCreateServiceSecurity(): Failed to set up window station ACE for admins (Status 0x%08lx)\n", Status);
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goto Quit;
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}
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/*
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* Administrators have some share of power over
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* the desktop object. They can enumerate desktops,
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* write and read upon the object itself.
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*/
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Status = RtlAddAccessAllowedAceEx(ServiceDacl,
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ACL_REVISION,
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INHERIT_ONLY_ACE | NO_PROPAGATE_INHERIT_ACE | OBJECT_INHERIT_ACE,
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DESKTOP_ENUMERATE | DESKTOP_READOBJECTS | DESKTOP_WRITEOBJECTS,
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SeExports->SeAliasAdminsSid);
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if (!NT_SUCCESS(Status))
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{
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ERR("IntCreateServiceSecurity(): Failed to set up desktop ACE for admins (Status 0x%08lx)\n", Status);
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goto Quit;
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}
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/* Set the DACL to absolute SD */
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Status = RtlSetDaclSecurityDescriptor(&AbsSD,
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TRUE,
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ServiceDacl,
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FALSE);
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if (!NT_SUCCESS(Status))
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{
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ERR("IntCreateServiceSecurity(): Failed to set up service DACL to absolute SD (Status 0x%08lx)\n", Status);
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goto Quit;
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}
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|
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/* This descriptor is ownerless */
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Status = RtlSetOwnerSecurityDescriptor(&AbsSD,
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NULL,
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FALSE);
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if (!NT_SUCCESS(Status))
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{
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ERR("IntCreateServiceSecurity(): Failed to make the absolute SD as ownerless (Status 0x%08lx)\n", Status);
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goto Quit;
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}
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|
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/* This descriptor has no primary group */
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Status = RtlSetGroupSecurityDescriptor(&AbsSD,
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NULL,
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FALSE);
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if (!NT_SUCCESS(Status))
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{
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ERR("IntCreateServiceSecurity(): Failed to make the absolute SD as having no primary group (Status 0x%08lx)\n", Status);
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goto Quit;
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}
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|
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/*
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* Determine how much size is needed to allocate
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* memory space for our relative security descriptor.
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*/
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Status = RtlAbsoluteToSelfRelativeSD(&AbsSD,
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NULL,
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&RelSDSize);
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if (Status != STATUS_BUFFER_TOO_SMALL)
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{
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ERR("IntCreateServiceSecurity(): Unexpected status code, must be STATUS_BUFFER_TOO_SMALL (Status 0x%08lx)\n", Status);
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goto Quit;
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}
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/* Allocate memory for this */
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RelSD = IntAllocateSecurityBuffer(RelSDSize);
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if (!RelSD)
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{
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ERR("IntCreateServiceSecurity(): Failed to allocate memory pool for relative SD!\n");
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Status = STATUS_NO_MEMORY;
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goto Quit;
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}
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|
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/* Convert the absolute SD into a relative one now */
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Status = RtlAbsoluteToSelfRelativeSD(&AbsSD,
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RelSD,
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&RelSDSize);
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if (!NT_SUCCESS(Status))
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{
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ERR("IntCreateServiceSecurity(): Failed to convert absolute SD to a relative one (Status 0x%08lx)\n", Status);
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goto Quit;
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}
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/* All good, give the SD to the caller */
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*ServiceSd = RelSD;
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Quit:
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|
if (ServiceDacl)
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|
{
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IntFreeSecurityBuffer(ServiceDacl);
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}
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|
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if (TokenUser)
|
|
{
|
|
IntFreeSecurityBuffer(TokenUser);
|
|
}
|
|
|
|
if (!NT_SUCCESS(Status))
|
|
{
|
|
if (RelSD)
|
|
{
|
|
IntFreeSecurityBuffer(RelSD);
|
|
}
|
|
}
|
|
|
|
return Status;
|
|
}
|
|
|
|
/* EOF */
|