tokenlif.c File Reference

#include <ntoskrnl.h>
#include <debug.h>

Include dependency graph for tokenlif.c:

Go to the source code of this file.

Macros
#define	NDEBUG
#define	SE_TOKEN_DYNAMIC_SLIM   500

Functions
NTSTATUS NTAPI	SepCreateToken (_Out_ PHANDLE TokenHandle, _In_ KPROCESSOR_MODE PreviousMode, _In_ ACCESS_MASK DesiredAccess, _In_opt_ POBJECT_ATTRIBUTES ObjectAttributes, _In_ TOKEN_TYPE TokenType, _In_ SECURITY_IMPERSONATION_LEVEL ImpersonationLevel, _In_ PLUID AuthenticationId, _In_ PLARGE_INTEGER ExpirationTime, _In_ PSID_AND_ATTRIBUTES User, _In_ ULONG GroupCount, _In_ PSID_AND_ATTRIBUTES Groups, _In_ ULONG GroupsLength, _In_ ULONG PrivilegeCount, _In_ PLUID_AND_ATTRIBUTES Privileges, _In_opt_ PSID Owner, _In_ PSID PrimaryGroup, _In_opt_ PACL DefaultDacl, _In_ PTOKEN_SOURCE TokenSource, _In_ BOOLEAN SystemToken)
	Internal function responsible for access token object creation in the kernel. A fully created token objected is inserted into the token handle, thus the handle becoming a valid handle to an access token object and ready for use.
NTSTATUS NTAPI	SepDuplicateToken (_In_ PTOKEN Token, _In_opt_ POBJECT_ATTRIBUTES ObjectAttributes, _In_ BOOLEAN EffectiveOnly, _In_ TOKEN_TYPE TokenType, _In_ SECURITY_IMPERSONATION_LEVEL Level, _In_ KPROCESSOR_MODE PreviousMode, _Out_ PTOKEN *NewAccessToken)
	Duplicates an access token, from an existing valid token.
static NTSTATUS	SepPerformTokenFiltering (_In_ PTOKEN Token, _In_opt_ PLUID_AND_ATTRIBUTES PrivilegesToBeDeleted, _In_opt_ PSID_AND_ATTRIBUTES SidsToBeDisabled, _In_opt_ PSID_AND_ATTRIBUTES RestrictedSidsIntoToken, _When_(PrivilegesToBeDeleted !=NULL, _In_) ULONG PrivilegesCount, _When_(SidsToBeDisabled !=NULL, _In_) ULONG RegularGroupsSidCount, _When_(RestrictedSidsIntoToken !=NULL, _In_) ULONG RestrictedSidsCount, _In_ ULONG PrivilegeFlags, _In_ KPROCESSOR_MODE PreviousMode, _Out_ PTOKEN *FilteredToken)
	Private helper function responsible for creating a restricted access token, that is, a filtered token from privileges and groups and with restricted SIDs added into the token on demand by the caller.
NTSTATUS NTAPI	SeFilterToken (_In_ PACCESS_TOKEN ExistingToken, _In_ ULONG Flags, _In_opt_ PTOKEN_GROUPS SidsToDisable, _In_opt_ PTOKEN_PRIVILEGES PrivilegesToDelete, _In_opt_ PTOKEN_GROUPS RestrictedSids, _Out_ PACCESS_TOKEN *FilteredToken)
	Filters an access token from an existing token, making it more restricted than the previous one.
__kernel_entry NTSTATUS NTAPI	NtCreateToken (_Out_ PHANDLE TokenHandle, _In_ ACCESS_MASK DesiredAccess, _In_opt_ POBJECT_ATTRIBUTES ObjectAttributes, _In_ TOKEN_TYPE TokenType, _In_ PLUID AuthenticationId, _In_ PLARGE_INTEGER ExpirationTime, _In_ PTOKEN_USER TokenUser, _In_ PTOKEN_GROUPS TokenGroups, _In_ PTOKEN_PRIVILEGES TokenPrivileges, _In_opt_ PTOKEN_OWNER TokenOwner, _In_ PTOKEN_PRIMARY_GROUP TokenPrimaryGroup, _In_opt_ PTOKEN_DEFAULT_DACL TokenDefaultDacl, _In_ PTOKEN_SOURCE TokenSource)
	Creates an access token.
_Must_inspect_result_ __kernel_entry NTSTATUS NTAPI	NtDuplicateToken (_In_ HANDLE ExistingTokenHandle, _In_ ACCESS_MASK DesiredAccess, _In_opt_ POBJECT_ATTRIBUTES ObjectAttributes, _In_ BOOLEAN EffectiveOnly, _In_ TOKEN_TYPE TokenType, _Out_ PHANDLE NewTokenHandle)
	Duplicates a token.
NTSTATUS NTAPI	NtFilterToken (_In_ HANDLE ExistingTokenHandle, _In_ ULONG Flags, _In_opt_ PTOKEN_GROUPS SidsToDisable, _In_opt_ PTOKEN_PRIVILEGES PrivilegesToDelete, _In_opt_ PTOKEN_GROUPS RestrictedSids, _Out_ PHANDLE NewTokenHandle)
	Creates an access token in a restricted form from the original existing token, that is, such action is called filtering.

Macro Definition Documentation

NDEBUG

#define NDEBUG

Definition at line 12 of file tokenlif.c.

SE_TOKEN_DYNAMIC_SLIM

#define SE_TOKEN_DYNAMIC_SLIM   500

Definition at line 17 of file tokenlif.c.

Function Documentation

NtCreateToken()

__kernel_entry NTSTATUS NTAPI NtCreateToken	(	_Out_ PHANDLE	TokenHandle,
		_In_ ACCESS_MASK	DesiredAccess,
		_In_opt_ POBJECT_ATTRIBUTES	ObjectAttributes,
		_In_ TOKEN_TYPE	TokenType,
		_In_ PLUID	AuthenticationId,
		_In_ PLARGE_INTEGER	ExpirationTime,
		_In_ PTOKEN_USER	TokenUser,
		_In_ PTOKEN_GROUPS	TokenGroups,
		_In_ PTOKEN_PRIVILEGES	TokenPrivileges,
		_In_opt_ PTOKEN_OWNER	TokenOwner,
		_In_ PTOKEN_PRIMARY_GROUP	TokenPrimaryGroup,
		_In_opt_ PTOKEN_DEFAULT_DACL	TokenDefaultDacl,
		_In_ PTOKEN_SOURCE	TokenSource
	)

Creates an access token.

Parameters

[out]	TokenHandle	The returned created token handle to the caller.
[in]	DesiredAccess	The desired access rights for the token that we're creating.
[in]	ObjectAttributes	The object attributes for the token object that we're creating.
[in]	TokenType	The type of token to assign for the newly created token.
[in]	AuthenticationId	Authentication ID that represents the token's identity.
[in]	ExpirationTime	Expiration time for the token. If set to -1, the token never expires.
[in]	TokenUser	The main user entity for the token to assign.
[in]	TokenGroups	Group list of SIDs for the token to assign.
[in]	TokenPrivileges	Privileges for the token.
[in]	TokenOwner	The main user that owns the newly created token.
[in]	TokenPrimaryGroup	The primary group that represents as the main group of the token.
[in]	TokenDefaultDacl	Discretionary access control list for the token. This limits on how the token can be used, accessed and used by whom.
[in]	TokenSource	The source origin of the token who creates it.

Returns

Returns STATUS_SUCCESS if the function has successfully created the token. A failure NTSTATUS code is returned otherwise.

Definition at line 1558 of file tokenlif.c.

{
    HANDLE hToken;
    KPROCESSOR_MODE PreviousMode;
    ULONG PrivilegeCount, GroupCount;
    PSID OwnerSid, PrimaryGroupSid;
    PACL DefaultDacl;
    LARGE_INTEGER LocalExpirationTime = {{0, 0}};
    LUID LocalAuthenticationId;
    TOKEN_SOURCE LocalTokenSource;
    SECURITY_QUALITY_OF_SERVICE LocalSecurityQos;
    PLUID_AND_ATTRIBUTES CapturedPrivileges = NULL;
    PSID_AND_ATTRIBUTES CapturedUser = NULL;
    PSID_AND_ATTRIBUTES CapturedGroups = NULL;
    PSID CapturedOwnerSid = NULL;
    PSID CapturedPrimaryGroupSid = NULL;
    PACL CapturedDefaultDacl = NULL;
    ULONG PrivilegesLength, UserLength, GroupsLength;
    NTSTATUS Status;
 
    PAGED_CODE();
 
    PreviousMode = ExGetPreviousMode();
 
    if (PreviousMode != KernelMode)
    {
        _SEH2_TRY
        {
            ProbeForWriteHandle(TokenHandle);
 
            if (ObjectAttributes != NULL)
            {
                ProbeForRead(ObjectAttributes,
                             sizeof(OBJECT_ATTRIBUTES),
                             sizeof(ULONG));
                LocalSecurityQos = *(SECURITY_QUALITY_OF_SERVICE*)ObjectAttributes->SecurityQualityOfService;
            }
 
            ProbeForRead(AuthenticationId,
                         sizeof(LUID),
                         sizeof(ULONG));
            LocalAuthenticationId = *AuthenticationId;
 
            LocalExpirationTime = ProbeForReadLargeInteger(ExpirationTime);
 
            ProbeForRead(TokenUser,
                         sizeof(TOKEN_USER),
                         sizeof(ULONG));
 
            ProbeForRead(TokenGroups,
                         sizeof(TOKEN_GROUPS),
                         sizeof(ULONG));
            GroupCount = TokenGroups->GroupCount;
 
            ProbeForRead(TokenPrivileges,
                         sizeof(TOKEN_PRIVILEGES),
                         sizeof(ULONG));
            PrivilegeCount = TokenPrivileges->PrivilegeCount;
 
            if (TokenOwner != NULL)
            {
                ProbeForRead(TokenOwner,
                             sizeof(TOKEN_OWNER),
                             sizeof(ULONG));
                OwnerSid = TokenOwner->Owner;
            }
            else
            {
                OwnerSid = NULL;
            }
 
            ProbeForRead(TokenPrimaryGroup,
                         sizeof(TOKEN_PRIMARY_GROUP),
                         sizeof(ULONG));
            PrimaryGroupSid = TokenPrimaryGroup->PrimaryGroup;
 
            if (TokenDefaultDacl != NULL)
            {
                ProbeForRead(TokenDefaultDacl,
                             sizeof(TOKEN_DEFAULT_DACL),
                             sizeof(ULONG));
                DefaultDacl = TokenDefaultDacl->DefaultDacl;
            }
            else
            {
                DefaultDacl = NULL;
            }
 
            ProbeForRead(TokenSource,
                         sizeof(TOKEN_SOURCE),
                         sizeof(ULONG));
            LocalTokenSource = *TokenSource;
        }
        _SEH2_EXCEPT(EXCEPTION_EXECUTE_HANDLER)
        {
            /* Return the exception code */
            _SEH2_YIELD(return _SEH2_GetExceptionCode());
        }
        _SEH2_END;
    }
    else
    {
        if (ObjectAttributes != NULL)
            LocalSecurityQos = *(SECURITY_QUALITY_OF_SERVICE*)ObjectAttributes->SecurityQualityOfService;
        LocalAuthenticationId = *AuthenticationId;
        LocalExpirationTime = *ExpirationTime;
        GroupCount = TokenGroups->GroupCount;
        PrivilegeCount = TokenPrivileges->PrivilegeCount;
        OwnerSid = TokenOwner ? TokenOwner->Owner : NULL;
        PrimaryGroupSid = TokenPrimaryGroup->PrimaryGroup;
        DefaultDacl = TokenDefaultDacl ? TokenDefaultDacl->DefaultDacl : NULL;
        LocalTokenSource = *TokenSource;
    }
 
    /* Check token type */
    if ((TokenType < TokenPrimary) ||
        (TokenType > TokenImpersonation))
    {
        return STATUS_BAD_TOKEN_TYPE;
    }
 
    /* Check for token creation privilege */
    if (!SeSinglePrivilegeCheck(SeCreateTokenPrivilege, PreviousMode))
    {
        return STATUS_PRIVILEGE_NOT_HELD;
    }
 
    /* Capture the user SID and attributes */
    Status = SeCaptureSidAndAttributesArray(&TokenUser->User,
                                            1,
                                            PreviousMode,
                                            NULL,
                                            0,
                                            PagedPool,
                                            FALSE,
                                            &CapturedUser,
                                            &UserLength);
    if (!NT_SUCCESS(Status))
    {
        goto Cleanup;
    }
 
    /* Capture the groups SID and attributes array */
    Status = SeCaptureSidAndAttributesArray(&TokenGroups->Groups[0],
                                            GroupCount,
                                            PreviousMode,
                                            NULL,
                                            0,
                                            PagedPool,
                                            FALSE,
                                            &CapturedGroups,
                                            &GroupsLength);
    if (!NT_SUCCESS(Status))
    {
        goto Cleanup;
    }
 
    /* Capture privileges */
    Status = SeCaptureLuidAndAttributesArray(&TokenPrivileges->Privileges[0],
                                             PrivilegeCount,
                                             PreviousMode,
                                             NULL,
                                             0,
                                             PagedPool,
                                             FALSE,
                                             &CapturedPrivileges,
                                             &PrivilegesLength);
    if (!NT_SUCCESS(Status))
    {
        goto Cleanup;
    }
 
    /* Capture the token owner SID */
    if (TokenOwner != NULL)
    {
        Status = SepCaptureSid(OwnerSid,
                               PreviousMode,
                               PagedPool,
                               FALSE,
                               &CapturedOwnerSid);
        if (!NT_SUCCESS(Status))
        {
            goto Cleanup;
        }
    }
 
    /* Capture the token primary group SID */
    Status = SepCaptureSid(PrimaryGroupSid,
                           PreviousMode,
                           PagedPool,
                           FALSE,
                           &CapturedPrimaryGroupSid);
    if (!NT_SUCCESS(Status))
    {
        goto Cleanup;
    }
 
    /* Capture DefaultDacl */
    if (DefaultDacl != NULL)
    {
        Status = SepCaptureAcl(DefaultDacl,
                               PreviousMode,
                               NonPagedPool,
                               FALSE,
                               &CapturedDefaultDacl);
        if (!NT_SUCCESS(Status))
        {
            goto Cleanup;
        }
    }
 
    /* Call the internal function */
    Status = SepCreateToken(&hToken,
                            PreviousMode,
                            DesiredAccess,
                            ObjectAttributes,
                            TokenType,
                            LocalSecurityQos.ImpersonationLevel,
                            &LocalAuthenticationId,
                            &LocalExpirationTime,
                            CapturedUser,
                            GroupCount,
                            CapturedGroups,
                            GroupsLength,
                            PrivilegeCount,
                            CapturedPrivileges,
                            CapturedOwnerSid,
                            CapturedPrimaryGroupSid,
                            CapturedDefaultDacl,
                            &LocalTokenSource,
                            FALSE);
    if (NT_SUCCESS(Status))
    {
        _SEH2_TRY
        {
            *TokenHandle = hToken;
        }
        _SEH2_EXCEPT(EXCEPTION_EXECUTE_HANDLER)
        {
            Status = _SEH2_GetExceptionCode();
        }
        _SEH2_END;
    }
 
Cleanup:
 
    /* Release what we captured */
    SeReleaseSidAndAttributesArray(CapturedUser, PreviousMode, FALSE);
    SeReleaseSidAndAttributesArray(CapturedGroups, PreviousMode, FALSE);
    SeReleaseLuidAndAttributesArray(CapturedPrivileges, PreviousMode, FALSE);
    SepReleaseSid(CapturedOwnerSid, PreviousMode, FALSE);
    SepReleaseSid(CapturedPrimaryGroupSid, PreviousMode, FALSE);
    SepReleaseAcl(CapturedDefaultDacl, PreviousMode, FALSE);
 
    return Status;
}

Referenced by LsapLogonUser().

NtDuplicateToken()

_Must_inspect_result_ __kernel_entry NTSTATUS NTAPI NtDuplicateToken	(	_In_ HANDLE	ExistingTokenHandle,
		_In_ ACCESS_MASK	DesiredAccess,
		_In_opt_ POBJECT_ATTRIBUTES	ObjectAttributes,
		_In_ BOOLEAN	EffectiveOnly,
		_In_ TOKEN_TYPE	TokenType,
		_Out_ PHANDLE	NewTokenHandle
	)

Duplicates a token.

Parameters

[in]	ExistingTokenHandle	An existing token to duplicate.
[in]	DesiredAccess	The desired access rights for the new duplicated token.
[in]	ObjectAttributes	Object attributes for the new duplicated token.
[in]	EffectiveOnly	If set to TRUE, the function removes all the disabled privileges and groups of the token to duplicate.
[in]	TokenType	Type of token to assign to the duplicated token.
[out]	NewTokenHandle	The returned duplicated token handle.

Returns

STATUS_SUCCESS is returned if token duplication has completed successfully. STATUS_BAD_IMPERSONATION_LEVEL is returned if the caller erroneously wants to raise the impersonation level even though the conditions do not permit it. A failure NTSTATUS code is returned otherwise.

Remarks

Some sources claim 4th param is ImpersonationLevel, but on W2K this is certainly NOT true, although I can't say for sure that EffectiveOnly is correct either. -Gunnar This is true. EffectiveOnly overrides SQOS.EffectiveOnly. - IAI NOTE for readers: http://hex.pp.ua/nt/NtDuplicateToken.php is therefore wrong in that regard, while MSDN documentation is correct.

Definition at line 1869 of file tokenlif.c.

{
    KPROCESSOR_MODE PreviousMode;
    HANDLE hToken;
    PTOKEN Token;
    PTOKEN NewToken;
    PSECURITY_QUALITY_OF_SERVICE CapturedSecurityQualityOfService;
    BOOLEAN QoSPresent;
    OBJECT_HANDLE_INFORMATION HandleInformation;
    NTSTATUS Status;
 
    PAGED_CODE();
 
    if (TokenType != TokenImpersonation &&
        TokenType != TokenPrimary)
    {
        return STATUS_INVALID_PARAMETER;
    }
 
    PreviousMode = KeGetPreviousMode();
 
    if (PreviousMode != KernelMode)
    {
        _SEH2_TRY
        {
            ProbeForWriteHandle(NewTokenHandle);
        }
        _SEH2_EXCEPT(EXCEPTION_EXECUTE_HANDLER)
        {
            /* Return the exception code */
            _SEH2_YIELD(return _SEH2_GetExceptionCode());
        }
        _SEH2_END;
    }
 
    Status = SepCaptureSecurityQualityOfService(ObjectAttributes,
                                                PreviousMode,
                                                PagedPool,
                                                FALSE,
                                                &CapturedSecurityQualityOfService,
                                                &QoSPresent);
    if (!NT_SUCCESS(Status))
    {
        DPRINT1("NtDuplicateToken() failed to capture QoS! Status: 0x%x\n", Status);
        return Status;
    }
 
    Status = ObReferenceObjectByHandle(ExistingTokenHandle,
                                       TOKEN_DUPLICATE,
                                       SeTokenObjectType,
                                       PreviousMode,
                                       (PVOID*)&Token,
                                       &HandleInformation);
    if (!NT_SUCCESS(Status))
    {
        DPRINT1("Failed to reference token (Status 0x%lx)\n", Status);
        SepReleaseSecurityQualityOfService(CapturedSecurityQualityOfService,
                                           PreviousMode,
                                           FALSE);
        return Status;
    }
 
    /*
     * Fail, if the original token is an impersonation token and the caller
     * tries to raise the impersonation level of the new token above the
     * impersonation level of the original token.
     */
    if (Token->TokenType == TokenImpersonation)
    {
        if (QoSPresent &&
            CapturedSecurityQualityOfService->ImpersonationLevel >Token->ImpersonationLevel)
        {
            ObDereferenceObject(Token);
            SepReleaseSecurityQualityOfService(CapturedSecurityQualityOfService,
                                               PreviousMode,
                                               FALSE);
            return STATUS_BAD_IMPERSONATION_LEVEL;
        }
    }
 
    /*
     * Fail, if a primary token is to be created from an impersonation token
     * and and the impersonation level of the impersonation token is below SecurityImpersonation.
     */
    if (Token->TokenType == TokenImpersonation &&
        TokenType == TokenPrimary &&
        Token->ImpersonationLevel < SecurityImpersonation)
    {
        ObDereferenceObject(Token);
        SepReleaseSecurityQualityOfService(CapturedSecurityQualityOfService,
                                           PreviousMode,
                                           FALSE);
        return STATUS_BAD_IMPERSONATION_LEVEL;
    }
 
    Status = SepDuplicateToken(Token,
                               ObjectAttributes,
                               EffectiveOnly,
                               TokenType,
                               (QoSPresent ? CapturedSecurityQualityOfService->ImpersonationLevel : SecurityAnonymous),
                               PreviousMode,
                               &NewToken);
 
    ObDereferenceObject(Token);
 
    if (NT_SUCCESS(Status))
    {
        Status = ObInsertObject(NewToken,
                                NULL,
                                (DesiredAccess ? DesiredAccess : HandleInformation.GrantedAccess),
                                0,
                                NULL,
                                &hToken);
        if (NT_SUCCESS(Status))
        {
            _SEH2_TRY
            {
                *NewTokenHandle = hToken;
            }
            _SEH2_EXCEPT(EXCEPTION_EXECUTE_HANDLER)
            {
                Status = _SEH2_GetExceptionCode();
            }
            _SEH2_END;
        }
    }
 
    /* Free the captured structure */
    SepReleaseSecurityQualityOfService(CapturedSecurityQualityOfService,
                                       PreviousMode,
                                       FALSE);
 
    return Status;
}

Referenced by CreateProcessAsUserCommon(), DuplicateTokenAsEffective(), DuplicateTokenEx(), GetToken(), GetTokenProcess(), ImpersonateLoggedOnUser(), QueryTokenImpersonationTests(), and START_TEST().

NtFilterToken()

NTSTATUS NTAPI NtFilterToken	(	_In_ HANDLE	ExistingTokenHandle,
		_In_ ULONG	Flags,
		_In_opt_ PTOKEN_GROUPS	SidsToDisable,
		_In_opt_ PTOKEN_PRIVILEGES	PrivilegesToDelete,
		_In_opt_ PTOKEN_GROUPS	RestrictedSids,
		_Out_ PHANDLE	NewTokenHandle
	)

Creates an access token in a restricted form from the original existing token, that is, such action is called filtering.

Parameters

[in]	ExistingTokenHandle	A handle to an access token which is to be filtered.
[in]	Flags	Privilege flag options. This parameter argument influences how the token's privileges are filtered. For further details see remarks.
[in]	SidsToDisable	Array of SIDs to disable. The action of doing so assigns the SE_GROUP_USE_FOR_DENY_ONLY attribute to the respective group SID and takes away SE_GROUP_ENABLED and SE_GROUP_ENABLED_BY_DEFAULT. This parameter can be NULL. This can be a UM pointer.
[in]	PrivilegesToDelete	Array of privileges to delete. The function will walk within this array to determine if the specified privileges do exist in the access token. Any missing privileges gets ignored. This parameter can be NULL. This can be a UM pointer.
[in]	RestrictedSids	An array list of restricted groups SID to be added in the access token. A token that is already restricted the newly added restricted SIDs are redundant information in addition to the existing restricted SIDs in the token. This parameter can be NULL. This can be a UM pointer.
[out]	NewTokenHandle	A new handle to the restricted (filtered) access token. This can be a UM pointer.

Returns

Returns STATUS_SUCCESS if the routine has successfully filtered the access token. STATUS_INVALID_PARAMETER is returned if one or more parameters are not valid (see SepPerformTokenFiltering routine call for more information). A failure NTSTATUS code is returned otherwise.

Remarks

The Flags parameter determines the final outcome of how the privileges in an access token are filtered. This parameter can take these supported values (these can be combined):

0 – Filter the token's privileges in the usual way. The function expects that the caller MUST PROVIDE a valid array list of privileges to be deleted (that is, PrivilegesToDelete MUSTN'T BE NULL).

DISABLE_MAX_PRIVILEGE – Disables (deletes) all the privileges except SeChangeNotifyPrivilege in the new access token. Bear in mind if this flag is specified the routine ignores PrivilegesToDelete.

SANDBOX_INERT – Stores the TOKEN_SANDBOX_INERT token flag within the access token.

LUA_TOKEN – The newly filtered access token is a LUA token. This flag is not supported in Windows Server 2003.

WRITE_RESTRICTED – The newly filtered token has the restricted SIDs that are considered only when evaluating write access onto the token. This value is not supported in Windows Server 2003.

Definition at line 2075 of file tokenlif.c.

{
    PTOKEN Token, FilteredToken;
    HANDLE FilteredTokenHandle;
    NTSTATUS Status;
    KPROCESSOR_MODE PreviousMode;
    OBJECT_HANDLE_INFORMATION HandleInfo;
    ULONG ResultLength;
    ULONG CapturedSidsCount = 0;
    ULONG CapturedPrivilegesCount = 0;
    ULONG CapturedRestrictedSidsCount = 0;
    ULONG ProbeSize = 0;
    PSID_AND_ATTRIBUTES CapturedSids = NULL;
    PSID_AND_ATTRIBUTES CapturedRestrictedSids = NULL;
    PLUID_AND_ATTRIBUTES CapturedPrivileges = NULL;
 
    PAGED_CODE();
 
    PreviousMode = ExGetPreviousMode();
 
    _SEH2_TRY
    {
        /* Probe SidsToDisable */
        if (SidsToDisable != NULL)
        {
            /* Probe the header */
            ProbeForRead(SidsToDisable, sizeof(*SidsToDisable), sizeof(ULONG));
 
            CapturedSidsCount = SidsToDisable->GroupCount;
            ProbeSize = FIELD_OFFSET(TOKEN_GROUPS, Groups[CapturedSidsCount]);
 
            ProbeForRead(SidsToDisable, ProbeSize, sizeof(ULONG));
        }
 
        /* Probe PrivilegesToDelete */
        if (PrivilegesToDelete != NULL)
        {
            /* Probe the header */
            ProbeForRead(PrivilegesToDelete, sizeof(*PrivilegesToDelete), sizeof(ULONG));
 
            CapturedPrivilegesCount = PrivilegesToDelete->PrivilegeCount;
            ProbeSize = FIELD_OFFSET(TOKEN_PRIVILEGES, Privileges[CapturedPrivilegesCount]);
 
            ProbeForRead(PrivilegesToDelete, ProbeSize, sizeof(ULONG));
        }
 
        /* Probe RestrictedSids */
        if (RestrictedSids != NULL)
        {
            /* Probe the header */
            ProbeForRead(RestrictedSids, sizeof(*RestrictedSids), sizeof(ULONG));
 
            CapturedRestrictedSidsCount = RestrictedSids->GroupCount;
            ProbeSize = FIELD_OFFSET(TOKEN_GROUPS, Groups[CapturedRestrictedSidsCount]);
 
            ProbeForRead(RestrictedSids, ProbeSize, sizeof(ULONG));
        }
 
        /* Probe the handle */
        ProbeForWriteHandle(NewTokenHandle);
    }
    _SEH2_EXCEPT(EXCEPTION_EXECUTE_HANDLER)
    {
        /* Return the exception code */
        _SEH2_YIELD(return _SEH2_GetExceptionCode());
    }
    _SEH2_END;
 
    /* Reference the token */
    Status = ObReferenceObjectByHandle(ExistingTokenHandle,
                                       TOKEN_DUPLICATE,
                                       SeTokenObjectType,
                                       PreviousMode,
                                       (PVOID*)&Token,
                                       &HandleInfo);
    if (!NT_SUCCESS(Status))
    {
        DPRINT1("NtFilterToken(): Failed to reference the token (Status 0x%lx)\n", Status);
        return Status;
    }
 
    /* Capture the group SIDs */
    if (SidsToDisable != NULL)
    {
        Status = SeCaptureSidAndAttributesArray(SidsToDisable->Groups,
                                                CapturedSidsCount,
                                                PreviousMode,
                                                NULL,
                                                0,
                                                PagedPool,
                                                TRUE,
                                                &CapturedSids,
                                                &ResultLength);
        if (!NT_SUCCESS(Status))
        {
            DPRINT1("NtFilterToken(): Failed to capture the SIDs (Status 0x%lx)\n", Status);
            goto Quit;
        }
    }
 
    /* Capture the privileges */
    if (PrivilegesToDelete != NULL)
    {
        Status = SeCaptureLuidAndAttributesArray(PrivilegesToDelete->Privileges,
                                                 CapturedPrivilegesCount,
                                                 PreviousMode,
                                                 NULL,
                                                 0,
                                                 PagedPool,
                                                 TRUE,
                                                 &CapturedPrivileges,
                                                 &ResultLength);
        if (!NT_SUCCESS(Status))
        {
            DPRINT1("NtFilterToken(): Failed to capture the privileges (Status 0x%lx)\n", Status);
            goto Quit;
        }
    }
 
    /* Capture the restricted SIDs */
    if (RestrictedSids != NULL)
    {
        Status = SeCaptureSidAndAttributesArray(RestrictedSids->Groups,
                                                CapturedRestrictedSidsCount,
                                                PreviousMode,
                                                NULL,
                                                0,
                                                PagedPool,
                                                TRUE,
                                                &CapturedRestrictedSids,
                                                &ResultLength);
        if (!NT_SUCCESS(Status))
        {
            DPRINT1("NtFilterToken(): Failed to capture the restricted SIDs (Status 0x%lx)\n", Status);
            goto Quit;
        }
    }
 
    /* Call the internal API */
    Status = SepPerformTokenFiltering(Token,
                                      CapturedPrivileges,
                                      CapturedSids,
                                      CapturedRestrictedSids,
                                      CapturedPrivilegesCount,
                                      CapturedSidsCount,
                                      CapturedRestrictedSidsCount,
                                      Flags,
                                      PreviousMode,
                                      &FilteredToken);
    if (!NT_SUCCESS(Status))
    {
        DPRINT1("NtFilterToken(): Failed to filter the token (Status 0x%lx)\n", Status);
        goto Quit;
    }
 
    /* Insert the filtered token and retrieve a handle to it */
    Status = ObInsertObject(FilteredToken,
                            NULL,
                            HandleInfo.GrantedAccess,
                            0,
                            NULL,
                            &FilteredTokenHandle);
    if (!NT_SUCCESS(Status))
    {
        DPRINT1("NtFilterToken(): Failed to insert the filtered token (Status 0x%lx)\n", Status);
        goto Quit;
    }
 
    /* And return it to the caller once we're done */
    _SEH2_TRY
    {
        *NewTokenHandle = FilteredTokenHandle;
    }
    _SEH2_EXCEPT(EXCEPTION_EXECUTE_HANDLER)
    {
        Status = _SEH2_GetExceptionCode();
        _SEH2_YIELD(goto Quit);
    }
    _SEH2_END;
 
Quit:
    /* Dereference the token */
    ObDereferenceObject(Token);
 
    /* Release all the captured data */
    if (CapturedSids != NULL)
    {
        SeReleaseSidAndAttributesArray(CapturedSids,
                                       PreviousMode,
                                       TRUE);
    }
 
    if (CapturedPrivileges != NULL)
    {
        SeReleaseLuidAndAttributesArray(CapturedPrivileges,
                                        PreviousMode,
                                        TRUE);
    }
 
    if (CapturedRestrictedSids != NULL)
    {
        SeReleaseSidAndAttributesArray(CapturedRestrictedSids,
                                       PreviousMode,
                                       TRUE);
    }
 
    return Status;
}

Referenced by CreateRestrictedToken(), QueryTokenIsSandboxInert(), QueryTokenPrivilegesAndGroupsTests(), QueryTokenRestrictedSidsTest(), and START_TEST().

SeFilterToken()

NTSTATUS NTAPI SeFilterToken	(	_In_ PACCESS_TOKEN	ExistingToken,
		_In_ ULONG	Flags,
		_In_opt_ PTOKEN_GROUPS	SidsToDisable,
		_In_opt_ PTOKEN_PRIVILEGES	PrivilegesToDelete,
		_In_opt_ PTOKEN_GROUPS	RestrictedSids,
		_Out_ PACCESS_TOKEN *	FilteredToken
	)

Filters an access token from an existing token, making it more restricted than the previous one.

Parameters

[in]	ExistingToken	An existing token for filtering.
[in]	Flags	Privilege flag options. This parameter argument influences how the token is filtered. Such parameter can be 0. See NtFilterToken syscall for more information.
[in]	SidsToDisable	Array of SIDs to disable. Such parameter can be NULL.
[in]	PrivilegesToDelete	Array of privileges to delete. If DISABLE_MAX_PRIVILEGE flag is specified in the Flags parameter, PrivilegesToDelete is ignored.
[in]	RestrictedSids	An array of restricted SIDs for the new filtered token. Such parameter can be NULL.
[out]	FilteredToken	The newly filtered token, returned to the caller.

Returns

Returns STATUS_SUCCESS if the function has successfully completed its operations and that the access token has been filtered. STATUS_INVALID_PARAMETER is returned if one or more of the parameter are not valid. A failure NTSTATUS code is returned otherwise.

Definition at line 1438 of file tokenlif.c.

{
    NTSTATUS Status;
    PTOKEN AccessToken;
    ULONG PrivilegesCount = 0;
    ULONG SidsCount = 0;
    ULONG RestrictedSidsCount = 0;
 
    PAGED_CODE();
 
    /* Begin copying the counters */
    if (SidsToDisable != NULL)
    {
        SidsCount = SidsToDisable->GroupCount;
    }
 
    if (PrivilegesToDelete != NULL)
    {
        PrivilegesCount = PrivilegesToDelete->PrivilegeCount;
    }
 
    if (RestrictedSids != NULL)
    {
        RestrictedSidsCount = RestrictedSids->GroupCount;
    }
 
    /* Call the internal API */
    Status = SepPerformTokenFiltering(ExistingToken,
                                      PrivilegesToDelete->Privileges,
                                      SidsToDisable->Groups,
                                      RestrictedSids->Groups,
                                      PrivilegesCount,
                                      SidsCount,
                                      RestrictedSidsCount,
                                      Flags,
                                      KernelMode,
                                      &AccessToken);
    if (!NT_SUCCESS(Status))
    {
        DPRINT1("SeFilterToken(): Failed to filter the token (Status 0x%lx)\n", Status);
        return Status;
    }
 
    /* Insert the filtered token */
    Status = ObInsertObject(AccessToken,
                            NULL,
                            0,
                            0,
                            NULL,
                            NULL);
    if (!NT_SUCCESS(Status))
    {
        DPRINT1("SeFilterToken(): Failed to insert the filtered token (Status 0x%lx)\n", Status);
        return Status;
    }
 
    /* Return it to the caller */
    *FilteredToken = AccessToken;
    return Status;
}

Referenced by FatCreateRestrictEveryoneToken(), and FilterToken().

SepCreateToken()

NTSTATUS NTAPI SepCreateToken	(	_Out_ PHANDLE	TokenHandle,
		_In_ KPROCESSOR_MODE	PreviousMode,
		_In_ ACCESS_MASK	DesiredAccess,
		_In_opt_ POBJECT_ATTRIBUTES	ObjectAttributes,
		_In_ TOKEN_TYPE	TokenType,
		_In_ SECURITY_IMPERSONATION_LEVEL	ImpersonationLevel,
		_In_ PLUID	AuthenticationId,
		_In_ PLARGE_INTEGER	ExpirationTime,
		_In_ PSID_AND_ATTRIBUTES	User,
		_In_ ULONG	GroupCount,
		_In_ PSID_AND_ATTRIBUTES	Groups,
		_In_ ULONG	GroupsLength,
		_In_ ULONG	PrivilegeCount,
		_In_ PLUID_AND_ATTRIBUTES	Privileges,
		_In_opt_ PSID	Owner,
		_In_ PSID	PrimaryGroup,
		_In_opt_ PACL	DefaultDacl,
		_In_ PTOKEN_SOURCE	TokenSource,
		_In_ BOOLEAN	SystemToken
	)

Internal function responsible for access token object creation in the kernel. A fully created token objected is inserted into the token handle, thus the handle becoming a valid handle to an access token object and ready for use.

Parameters

[out]	TokenHandle	Valid token handle that's ready for use after token creation and object insertion.
[in]	PreviousMode	Processor request level mode.
[in]	DesiredAccess	Desired access right for the token object to be granted. This kind of access right impacts how the token can be used and who.
[in]	ObjectAttributes	Object attributes for the token to be created.
[in]	TokenType	Type of token to assign upon creation.
[in]	ImpersonationLevel	Security impersonation level of token to assign upon creation.
[in]	AuthenticationId	Authentication ID that represents the authentication information of the token.
[in]	ExpirationTime	Expiration time of the token to assign. A value of -1 means that the token never expires and its life depends upon the amount of references this token object has.
[in]	User	User entry to assign to the token.
[in]	GroupCount	The total number of groups count for the token.
[in]	Groups	The group entries for the token.
[in]	GroupsLength	The length size of the groups array, pointed by the Groups parameter.
[in]	PrivilegeCount	The total number of priivleges that the newly created token has.
[in]	Privileges	The privileges for the token.
[in]	Owner	The main user (or also owner) that represents the token that we create.
[in]	PrimaryGroup	The main group that represents the token that we create.
[in]	DefaultDacl	A discretionary access control list for the token.
[in]	TokenSource	Source (or the origin) of the access token that creates it.
[in]	SystemToken	If set to TRUE, the newly created token is a system token and only in charge by the internal system. The function directly returns a pointer to the created token object for system kernel use. Otherwise if set to FALSE, the function inserts the object to a handle making it a regular access token.

Returns

Returns STATUS_SUCCESS if token creation has completed successfully. STATUS_INSUFFICIENT_RESOURCES is returned if the dynamic area of memory of the token hasn't been allocated because of lack of memory resources. A failure NTSTATUS code is returned otherwise.

Definition at line 97 of file tokenlif.c.

{
    NTSTATUS Status;
    PTOKEN AccessToken;
    ULONG TokenFlags = 0;
    ULONG PrimaryGroupIndex, DefaultOwnerIndex;
    LUID TokenId;
    LUID ModifiedId;
    PVOID EndMem;
    ULONG PrivilegesLength;
    ULONG UserGroupsLength;
    ULONG VariableLength;
    ULONG DynamicPartSize, TotalSize;
    ULONG TokenPagedCharges;
    ULONG i;
 
    PAGED_CODE();
 
    /* Loop all groups */
    for (i = 0; i < GroupCount; i++)
    {
        /* Check for mandatory groups */
        if (Groups[i].Attributes & SE_GROUP_MANDATORY)
        {
            /* Force them to be enabled */
            Groups[i].Attributes |= (SE_GROUP_ENABLED | SE_GROUP_ENABLED_BY_DEFAULT);
        }
 
        /* Check of the group is an admin group */
        if (RtlEqualSid(SeAliasAdminsSid, Groups[i].Sid))
        {
            /* Remember this so we can optimize queries later */
            TokenFlags |= TOKEN_HAS_ADMIN_GROUP;
        }
    }
 
    /* Allocate unique IDs for the token */
    ExAllocateLocallyUniqueId(&TokenId);
    ExAllocateLocallyUniqueId(&ModifiedId);
 
    /* Compute how much size we need to allocate for the token */
 
    /* Privileges size */
    PrivilegesLength = PrivilegeCount * sizeof(LUID_AND_ATTRIBUTES);
    PrivilegesLength = ALIGN_UP_BY(PrivilegesLength, sizeof(PVOID));
 
    /* User and groups size */
    UserGroupsLength = (1 + GroupCount) * sizeof(SID_AND_ATTRIBUTES);
    UserGroupsLength += RtlLengthSid(User->Sid);
    for (i = 0; i < GroupCount; i++)
    {
        UserGroupsLength += RtlLengthSid(Groups[i].Sid);
    }
    UserGroupsLength = ALIGN_UP_BY(UserGroupsLength, sizeof(PVOID));
 
    /* Add the additional groups array length */
    UserGroupsLength += ALIGN_UP_BY(GroupsLength, sizeof(PVOID));
 
    VariableLength = PrivilegesLength + UserGroupsLength;
    TotalSize = FIELD_OFFSET(TOKEN, VariablePart) + VariableLength;
 
    /*
     * A token is considered slim if it has the default dynamic
     * contents, or in other words, the primary group and ACL.
     * We judge if such contents are default by checking their
     * total size if it's over the range. On Windows this range
     * is 0x1F4 (aka 500). If the size of the whole dynamic contents
     * is over that range then the token is considered fat and
     * the token will be charged the whole of its token body length
     * plus the dynamic size.
     */
    DynamicPartSize = DefaultDacl ? DefaultDacl->AclSize : 0;
    DynamicPartSize += RtlLengthSid(PrimaryGroup);
    if (DynamicPartSize > SE_TOKEN_DYNAMIC_SLIM)
    {
        TokenPagedCharges = DynamicPartSize + TotalSize;
    }
    else
    {
        TokenPagedCharges = SE_TOKEN_DYNAMIC_SLIM + TotalSize;
    }
 
    Status = ObCreateObject(PreviousMode,
                            SeTokenObjectType,
                            ObjectAttributes,
                            PreviousMode,
                            NULL,
                            TotalSize,
                            TokenPagedCharges,
                            0,
                            (PVOID*)&AccessToken);
    if (!NT_SUCCESS(Status))
    {
        DPRINT1("ObCreateObject() failed (Status 0x%lx)\n", Status);
        return Status;
    }
 
    /* Zero out the buffer and initialize the token */
    RtlZeroMemory(AccessToken, TotalSize);
 
    AccessToken->TokenId = TokenId;
    AccessToken->TokenType = TokenType;
    AccessToken->ImpersonationLevel = ImpersonationLevel;
 
    /* Initialise the lock for the access token */
    Status = SepCreateTokenLock(AccessToken);
    if (!NT_SUCCESS(Status))
        goto Quit;
 
    AccessToken->TokenSource.SourceIdentifier = TokenSource->SourceIdentifier;
    RtlCopyMemory(AccessToken->TokenSource.SourceName,
                  TokenSource->SourceName,
                  sizeof(TokenSource->SourceName));
 
    AccessToken->ExpirationTime = *ExpirationTime;
    AccessToken->ModifiedId = ModifiedId;
    AccessToken->DynamicCharged = TokenPagedCharges - TotalSize;
 
    AccessToken->TokenFlags = TokenFlags & ~TOKEN_SESSION_NOT_REFERENCED;
 
    /* Copy and reference the logon session */
    AccessToken->AuthenticationId = *AuthenticationId;
    Status = SepRmReferenceLogonSession(&AccessToken->AuthenticationId);
    if (!NT_SUCCESS(Status))
    {
        /* No logon session could be found, bail out */
        DPRINT1("SepRmReferenceLogonSession() failed (Status 0x%lx)\n", Status);
        /* Set the flag for proper cleanup by the delete procedure */
        AccessToken->TokenFlags |= TOKEN_SESSION_NOT_REFERENCED;
        goto Quit;
    }
 
    /* Insert the referenced logon session into the token */
    Status = SepRmInsertLogonSessionIntoToken(AccessToken);
    if (!NT_SUCCESS(Status))
    {
        /* Failed to insert the logon session into the token, bail out */
        DPRINT1("SepRmInsertLogonSessionIntoToken() failed (Status 0x%lx)\n", Status);
        goto Quit;
    }
 
    /* Fill in token debug information */
#if DBG
    /*
     * We must determine ourselves that the current
     * process is not the initial CPU one. The initial
     * process is not a "real" process, that is, the
     * Process Manager has not yet been initialized and
     * as a matter of fact we are creating a token before
     * any process gets created by Ps. If it turns out
     * that the current process is the initial CPU process
     * where token creation execution takes place, don't
     * do anything.
     */
    if (PsGetCurrentProcess() != &KiInitialProcess)
    {
        RtlCopyMemory(AccessToken->ImageFileName,
                      PsGetCurrentProcess()->ImageFileName,
                      min(sizeof(AccessToken->ImageFileName), sizeof(PsGetCurrentProcess()->ImageFileName)));
 
        AccessToken->ProcessCid = PsGetCurrentProcessId();
        AccessToken->ThreadCid = PsGetCurrentThreadId();
    }
 
    AccessToken->CreateMethod = TOKEN_CREATE_METHOD;
#endif
 
    /* Assign the data that reside in the token's variable information area */
    AccessToken->VariableLength = VariableLength;
    EndMem = (PVOID)&AccessToken->VariablePart;
 
    /* Copy the privileges */
    AccessToken->PrivilegeCount = PrivilegeCount;
    AccessToken->Privileges = NULL;
    if (PrivilegeCount > 0)
    {
        AccessToken->Privileges = EndMem;
        EndMem = (PVOID)((ULONG_PTR)EndMem + PrivilegesLength);
        VariableLength -= PrivilegesLength;
 
        if (PreviousMode != KernelMode)
        {
            _SEH2_TRY
            {
                RtlCopyMemory(AccessToken->Privileges,
                              Privileges,
                              PrivilegeCount * sizeof(LUID_AND_ATTRIBUTES));
            }
            _SEH2_EXCEPT(EXCEPTION_EXECUTE_HANDLER)
            {
                Status = _SEH2_GetExceptionCode();
            }
            _SEH2_END;
        }
        else
        {
            RtlCopyMemory(AccessToken->Privileges,
                          Privileges,
                          PrivilegeCount * sizeof(LUID_AND_ATTRIBUTES));
        }
 
        if (!NT_SUCCESS(Status))
            goto Quit;
    }
 
    /* Update the privilege flags */
    SepUpdatePrivilegeFlagsToken(AccessToken);
 
    /* Copy the user and groups */
    AccessToken->UserAndGroupCount = 1 + GroupCount;
    AccessToken->UserAndGroups = EndMem;
    EndMem = &AccessToken->UserAndGroups[AccessToken->UserAndGroupCount];
    VariableLength -= ((ULONG_PTR)EndMem - (ULONG_PTR)AccessToken->UserAndGroups);
 
    Status = RtlCopySidAndAttributesArray(1,
                                          User,
                                          VariableLength,
                                          &AccessToken->UserAndGroups[0],
                                          EndMem,
                                          &EndMem,
                                          &VariableLength);
    if (!NT_SUCCESS(Status))
        goto Quit;
 
    Status = RtlCopySidAndAttributesArray(GroupCount,
                                          Groups,
                                          VariableLength,
                                          &AccessToken->UserAndGroups[1],
                                          EndMem,
                                          &EndMem,
                                          &VariableLength);
    if (!NT_SUCCESS(Status))
        goto Quit;
 
    /* Find the token primary group and default owner */
    Status = SepFindPrimaryGroupAndDefaultOwner(AccessToken,
                                                PrimaryGroup,
                                                Owner,
                                                &PrimaryGroupIndex,
                                                &DefaultOwnerIndex);
    if (!NT_SUCCESS(Status))
    {
        DPRINT1("SepFindPrimaryGroupAndDefaultOwner failed (Status 0x%lx)\n", Status);
        goto Quit;
    }
 
    /*
     * Now allocate the token's dynamic information area
     * and set the data. The dynamic part consists of two
     * contents, the primary group SID and the default DACL
     * of the token, in this strict order.
     */
    AccessToken->DynamicPart = ExAllocatePoolWithTag(PagedPool,
                                                     DynamicPartSize,
                                                     TAG_TOKEN_DYNAMIC);
    if (AccessToken->DynamicPart == NULL)
    {
        Status = STATUS_INSUFFICIENT_RESOURCES;
        goto Quit;
    }
 
    /* Unused memory in the dynamic area */
    AccessToken->DynamicAvailable = 0;
 
    /*
     * Assign the primary group to the token
     * and put it in the dynamic part as well.
     */
    EndMem = (PVOID)AccessToken->DynamicPart;
    AccessToken->PrimaryGroup = EndMem;
    RtlCopySid(RtlLengthSid(AccessToken->UserAndGroups[PrimaryGroupIndex].Sid),
                            EndMem,
                            AccessToken->UserAndGroups[PrimaryGroupIndex].Sid);
    AccessToken->DefaultOwnerIndex = DefaultOwnerIndex;
    EndMem = (PVOID)((ULONG_PTR)EndMem + RtlLengthSid(AccessToken->UserAndGroups[PrimaryGroupIndex].Sid));
 
    /*
     * We have assigned a primary group and put it in the
     * dynamic part, now it's time to copy the provided
     * default DACL (if it's provided to begin with) into
     * the DACL field of the token and put it at the end
     * tail of the dynamic part too.
     */
    if (DefaultDacl != NULL)
    {
        AccessToken->DefaultDacl = EndMem;
 
        RtlCopyMemory(EndMem,
                      DefaultDacl,
                      DefaultDacl->AclSize);
    }
 
    /* Insert the token only if it's not the system token, otherwise return it directly */
    if (!SystemToken)
    {
        Status = ObInsertObject(AccessToken,
                                NULL,
                                DesiredAccess,
                                0,
                                NULL,
                                TokenHandle);
        if (!NT_SUCCESS(Status))
        {
            DPRINT1("ObInsertObject() failed (Status 0x%lx)\n", Status);
        }
    }
    else
    {
        /* Return pointer instead of handle */
        *TokenHandle = (HANDLE)AccessToken;
    }
 
Quit:
    if (!NT_SUCCESS(Status))
    {
        /* Dereference the token, the delete procedure will clean it up */
        ObDereferenceObject(AccessToken);
    }
 
    return Status;
}

Referenced by NtCreateToken(), SepCreateSystemAnonymousLogonToken(), SepCreateSystemAnonymousLogonTokenNoEveryone(), and SepCreateSystemProcessToken().

SepDuplicateToken()

NTSTATUS NTAPI SepDuplicateToken	(	_In_ PTOKEN	Token,
		_In_opt_ POBJECT_ATTRIBUTES	ObjectAttributes,
		_In_ BOOLEAN	EffectiveOnly,
		_In_ TOKEN_TYPE	TokenType,
		_In_ SECURITY_IMPERSONATION_LEVEL	Level,
		_In_ KPROCESSOR_MODE	PreviousMode,
		_Out_ PTOKEN *	NewAccessToken
	)

Duplicates an access token, from an existing valid token.

Parameters

[in]	Token	Access token to duplicate.
[in]	ObjectAttributes	Object attributes for the new token.
[in]	EffectiveOnly	If set to TRUE, the function removes all the disabled privileges and groups of the token to duplicate.
[in]	TokenType	Type of token.
[in]	Level	Security impersonation level of a token.
[in]	PreviousMode	The processor request level mode.
[out]	NewAccessToken	The duplicated token.

Returns

Returns STATUS_SUCCESS if the token has been duplicated. STATUS_INSUFFICIENT_RESOURCES is returned if memory pool allocation of the dynamic part of the token for duplication has failed due to the lack of memory resources. A failure NTSTATUS code is returned otherwise.

Definition at line 471 of file tokenlif.c.

{
    NTSTATUS Status;
    PTOKEN AccessToken;
    PVOID EndMem;
    ULONG PrimaryGroupIndex;
    ULONG VariableLength;
    ULONG DynamicPartSize, TotalSize;
    ULONG PrivilegesIndex, GroupsIndex;
 
    PAGED_CODE();
 
    /* Compute how much size we need to allocate for the token */
    VariableLength = Token->VariableLength;
    TotalSize = FIELD_OFFSET(TOKEN, VariablePart) + VariableLength;
 
    /*
     * Compute how much size we need to allocate
     * the dynamic part of the newly duplicated
     * token.
     */
    DynamicPartSize = Token->DefaultDacl ? Token->DefaultDacl->AclSize : 0;
    DynamicPartSize += RtlLengthSid(Token->PrimaryGroup);
 
    Status = ObCreateObject(PreviousMode,
                            SeTokenObjectType,
                            ObjectAttributes,
                            PreviousMode,
                            NULL,
                            TotalSize,
                            Token->DynamicCharged,
                            TotalSize,
                            (PVOID*)&AccessToken);
    if (!NT_SUCCESS(Status))
    {
        DPRINT1("ObCreateObject() failed (Status 0x%lx)\n", Status);
        return Status;
    }
 
    /* Zero out the buffer and initialize the token */
    RtlZeroMemory(AccessToken, TotalSize);
 
    ExAllocateLocallyUniqueId(&AccessToken->TokenId);
 
    AccessToken->TokenType = TokenType;
    AccessToken->ImpersonationLevel = Level;
 
    /* Initialise the lock for the access token */
    Status = SepCreateTokenLock(AccessToken);
    if (!NT_SUCCESS(Status))
    {
        ObDereferenceObject(AccessToken);
        return Status;
    }
 
    /* Copy the immutable fields */
    AccessToken->TokenSource.SourceIdentifier = Token->TokenSource.SourceIdentifier;
    RtlCopyMemory(AccessToken->TokenSource.SourceName,
                  Token->TokenSource.SourceName,
                  sizeof(Token->TokenSource.SourceName));
 
    AccessToken->AuthenticationId = Token->AuthenticationId;
    AccessToken->ParentTokenId = Token->ParentTokenId;
    AccessToken->ExpirationTime = Token->ExpirationTime;
    AccessToken->OriginatingLogonSession = Token->OriginatingLogonSession;
    AccessToken->DynamicCharged = Token->DynamicCharged;
 
    /* Lock the source token and copy the mutable fields */
    SepAcquireTokenLockShared(Token);
 
    AccessToken->SessionId = Token->SessionId;
    AccessToken->ModifiedId = Token->ModifiedId;
 
    AccessToken->TokenFlags = Token->TokenFlags & ~TOKEN_SESSION_NOT_REFERENCED;
 
    /* Reference the logon session */
    Status = SepRmReferenceLogonSession(&AccessToken->AuthenticationId);
    if (!NT_SUCCESS(Status))
    {
        /* No logon session could be found, bail out */
        DPRINT1("SepRmReferenceLogonSession() failed (Status 0x%lx)\n", Status);
        /* Set the flag for proper cleanup by the delete procedure */
        AccessToken->TokenFlags |= TOKEN_SESSION_NOT_REFERENCED;
        goto Quit;
    }
 
    /* Insert the referenced logon session into the token */
    Status = SepRmInsertLogonSessionIntoToken(AccessToken);
    if (!NT_SUCCESS(Status))
    {
        /* Failed to insert the logon session into the token, bail out */
        DPRINT1("SepRmInsertLogonSessionIntoToken() failed (Status 0x%lx)\n", Status);
        goto Quit;
    }
 
    /* Fill in token debug information */
#if DBG
    RtlCopyMemory(AccessToken->ImageFileName,
                  PsGetCurrentProcess()->ImageFileName,
                  min(sizeof(AccessToken->ImageFileName), sizeof(PsGetCurrentProcess()->ImageFileName)));
 
    AccessToken->ProcessCid = PsGetCurrentProcessId();
    AccessToken->ThreadCid = PsGetCurrentThreadId();
    AccessToken->CreateMethod = TOKEN_DUPLICATE_METHOD;
#endif
 
    /* Assign the data that reside in the token's variable information area */
    AccessToken->VariableLength = VariableLength;
    EndMem = (PVOID)&AccessToken->VariablePart;
 
    /* Copy the privileges */
    AccessToken->PrivilegeCount = 0;
    AccessToken->Privileges = NULL;
    if (Token->Privileges && (Token->PrivilegeCount > 0))
    {
        ULONG PrivilegesLength = Token->PrivilegeCount * sizeof(LUID_AND_ATTRIBUTES);
        PrivilegesLength = ALIGN_UP_BY(PrivilegesLength, sizeof(PVOID));
 
        ASSERT(VariableLength >= PrivilegesLength);
 
        AccessToken->PrivilegeCount = Token->PrivilegeCount;
        AccessToken->Privileges = EndMem;
        EndMem = (PVOID)((ULONG_PTR)EndMem + PrivilegesLength);
        VariableLength -= PrivilegesLength;
 
        RtlCopyMemory(AccessToken->Privileges,
                      Token->Privileges,
                      AccessToken->PrivilegeCount * sizeof(LUID_AND_ATTRIBUTES));
    }
 
    /* Copy the user and groups */
    AccessToken->UserAndGroupCount = 0;
    AccessToken->UserAndGroups = NULL;
    if (Token->UserAndGroups && (Token->UserAndGroupCount > 0))
    {
        AccessToken->UserAndGroupCount = Token->UserAndGroupCount;
        AccessToken->UserAndGroups = EndMem;
        EndMem = &AccessToken->UserAndGroups[AccessToken->UserAndGroupCount];
        VariableLength -= ((ULONG_PTR)EndMem - (ULONG_PTR)AccessToken->UserAndGroups);
 
        Status = RtlCopySidAndAttributesArray(AccessToken->UserAndGroupCount,
                                              Token->UserAndGroups,
                                              VariableLength,
                                              AccessToken->UserAndGroups,
                                              EndMem,
                                              &EndMem,
                                              &VariableLength);
        if (!NT_SUCCESS(Status))
        {
            DPRINT1("RtlCopySidAndAttributesArray(UserAndGroups) failed (Status 0x%lx)\n", Status);
            goto Quit;
        }
    }
 
    /* Find the token primary group */
    Status = SepFindPrimaryGroupAndDefaultOwner(AccessToken,
                                                Token->PrimaryGroup,
                                                NULL,
                                                &PrimaryGroupIndex,
                                                NULL);
    if (!NT_SUCCESS(Status))
    {
        DPRINT1("SepFindPrimaryGroupAndDefaultOwner failed (Status 0x%lx)\n", Status);
        goto Quit;
    }
 
    /* Copy the restricted SIDs */
    AccessToken->RestrictedSidCount = 0;
    AccessToken->RestrictedSids = NULL;
    if (Token->RestrictedSids && (Token->RestrictedSidCount > 0))
    {
        AccessToken->RestrictedSidCount = Token->RestrictedSidCount;
        AccessToken->RestrictedSids = EndMem;
        EndMem = &AccessToken->RestrictedSids[AccessToken->RestrictedSidCount];
        VariableLength -= ((ULONG_PTR)EndMem - (ULONG_PTR)AccessToken->RestrictedSids);
 
        Status = RtlCopySidAndAttributesArray(AccessToken->RestrictedSidCount,
                                              Token->RestrictedSids,
                                              VariableLength,
                                              AccessToken->RestrictedSids,
                                              EndMem,
                                              &EndMem,
                                              &VariableLength);
        if (!NT_SUCCESS(Status))
        {
            DPRINT1("RtlCopySidAndAttributesArray(RestrictedSids) failed (Status 0x%lx)\n", Status);
            goto Quit;
        }
    }
 
    /* Now allocate the token's dynamic information area and set the data */
    AccessToken->DynamicPart = ExAllocatePoolWithTag(PagedPool,
                                                     DynamicPartSize,
                                                     TAG_TOKEN_DYNAMIC);
    if (AccessToken->DynamicPart == NULL)
    {
        Status = STATUS_INSUFFICIENT_RESOURCES;
        goto Quit;
    }
 
    /* Unused memory in the dynamic area */
    AccessToken->DynamicAvailable = 0;
 
    /*
     * Assign the primary group to the token
     * and put it in the dynamic part as well.
     */
    EndMem = (PVOID)AccessToken->DynamicPart;
    AccessToken->PrimaryGroup = EndMem;
    RtlCopySid(RtlLengthSid(AccessToken->UserAndGroups[PrimaryGroupIndex].Sid),
                            EndMem,
                            AccessToken->UserAndGroups[PrimaryGroupIndex].Sid);
    AccessToken->DefaultOwnerIndex = Token->DefaultOwnerIndex;
    EndMem = (PVOID)((ULONG_PTR)EndMem + RtlLengthSid(AccessToken->UserAndGroups[PrimaryGroupIndex].Sid));
 
    /*
     * The existing token has a default DACL only
     * if it has an allocated dynamic part.
     */
    if (Token->DynamicPart && Token->DefaultDacl)
    {
        AccessToken->DefaultDacl = EndMem;
 
        RtlCopyMemory(EndMem,
                      Token->DefaultDacl,
                      Token->DefaultDacl->AclSize);
    }
 
    /*
     * Filter the token by removing the disabled privileges
     * and groups if the caller wants to duplicate an access
     * token as effective only.
     */
    if (EffectiveOnly)
    {
        /*
         * Begin querying the groups and search for disabled ones. Do not touch the
         * user which is at the first position because it cannot be disabled, no
         * matter what attributes it has.
         */
        for (GroupsIndex = 1; GroupsIndex < AccessToken->UserAndGroupCount; GroupsIndex++)
        {
            /*
             * A group is considered disabled if its attributes is either
             * 0 or SE_GROUP_ENABLED is not included in the attributes flags list.
             * That is because a certain user and/or group can have several attributes
             * that bear no influence on whether a user/group is enabled or not
             * (SE_GROUP_ENABLED_BY_DEFAULT for example which is a mere indicator
             * that the group has just been enabled by default). A mandatory
             * group (that is, the group has SE_GROUP_MANDATORY attribute)
             * by standards it's always enabled and no one can disable it.
             */
            if (AccessToken->UserAndGroups[GroupsIndex].Attributes == 0 ||
                (AccessToken->UserAndGroups[GroupsIndex].Attributes & SE_GROUP_ENABLED) == 0)
            {
                /*
                 * If this group is an administrators group
                 * and the token belongs to such group,
                 * we've to take away TOKEN_HAS_ADMIN_GROUP
                 * for the fact that's not enabled and as
                 * such the token no longer belongs to
                 * this group.
                 */
                if (RtlEqualSid(SeAliasAdminsSid,
                                &AccessToken->UserAndGroups[GroupsIndex].Sid))
                {
                    AccessToken->TokenFlags &= ~TOKEN_HAS_ADMIN_GROUP;
                }
 
                /*
                 * A group is not enabled, it's time to remove
                 * from the token and update the groups index
                 * accordingly and continue with the next group.
                 */
                SepRemoveUserGroupToken(AccessToken, GroupsIndex);
                GroupsIndex--;
            }
        }
 
        /* Begin querying the privileges and search for disabled ones */
        for (PrivilegesIndex = 0; PrivilegesIndex < AccessToken->PrivilegeCount; PrivilegesIndex++)
        {
            /*
             * A privilege is considered disabled if its attributes is either
             * 0 or SE_PRIVILEGE_ENABLED is not included in the attributes flags list.
             * That is because a certain privilege can have several attributes
             * that bear no influence on whether a privilege is enabled or not
             * (SE_PRIVILEGE_ENABLED_BY_DEFAULT for example which is a mere indicator
             * that the privilege has just been enabled by default).
             */
            if (AccessToken->Privileges[PrivilegesIndex].Attributes == 0 ||
                (AccessToken->Privileges[PrivilegesIndex].Attributes & SE_PRIVILEGE_ENABLED) == 0)
            {
                /*
                 * A privilege is not enabled, therefor it's time
                 * to strip it from the token and continue with the next
                 * privilege. Of course we must also want to update the
                 * privileges index accordingly.
                 */
                SepRemovePrivilegeToken(AccessToken, PrivilegesIndex);
                PrivilegesIndex--;
            }
        }
    }
 
    /* Return the token to the caller */
    *NewAccessToken = AccessToken;
    Status = STATUS_SUCCESS;
 
Quit:
    if (!NT_SUCCESS(Status))
    {
        /* Dereference the token, the delete procedure will clean it up */
        ObDereferenceObject(AccessToken);
    }
 
    /* Unlock the source token */
    SepReleaseTokenLock(Token);
 
    return Status;
}

Referenced by NtDuplicateToken(), SeCopyClientToken(), SepOpenThreadToken(), and SeSubProcessToken().

SepPerformTokenFiltering()

static NTSTATUS SepPerformTokenFiltering ( _In_ PTOKEN  Token, _In_opt_ PLUID_AND_ATTRIBUTES  PrivilegesToBeDeleted, _In_opt_ PSID_AND_ATTRIBUTES  SidsToBeDisabled, _In_opt_ PSID_AND_ATTRIBUTES  RestrictedSidsIntoToken, _When_(PrivilegesToBeDeleted !=NULL, _In_) ULONG  PrivilegesCount, _When_(SidsToBeDisabled !=NULL, _In_) ULONG  RegularGroupsSidCount, _When_(RestrictedSidsIntoToken !=NULL, _In_) ULONG  RestrictedSidsCount, _In_ ULONG  PrivilegeFlags, _In_ KPROCESSOR_MODE  PreviousMode, _Out_ PTOKEN *  FilteredToken  )

static

Private helper function responsible for creating a restricted access token, that is, a filtered token from privileges and groups and with restricted SIDs added into the token on demand by the caller.

Parameters

[in]	Token	An existing and valid access token.
[in]	PrivilegesToBeDeleted	A list of privileges to be deleted within the token that's going to be filtered. This parameter is ignored if the caller wants to disable all the privileges by specifying DISABLE_MAX_PRIVILEGE in the flags parameter.
[in]	SidsToBeDisabled	A list of group SIDs to be disabled within the token. This parameter can be NULL.
[in]	RestrictedSidsIntoToken	A list of restricted SIDs to be added into the token. This parameter can be NULL.
[in]	PrivilegesCount	The privilege count of the privileges list.
[in]	RegularGroupsSidCount	The SIDs count of the group SIDs list.
[in]	RestrictedSidsCount	The restricted SIDs count of restricted SIDs list.
[in]	PrivilegeFlags	Influences how the privileges should be filtered in an access token. See NtFilterToken syscall for more information.
[in]	PreviousMode	Processor level access mode.
[out]	FilteredToken	The filtered token, returned to the caller.

Returns

Returns STATUS_SUCCESS if token token filtering has completed successfully. STATUS_INVALID_PARAMETER is returned if one or more of the parameters do not meet the conditions imposed by the function. A failure NTSTATUS code is returned otherwise.

Remarks

The final outcome of privileges and/or SIDs filtering is not always deterministic. That is, any privileges or SIDs that aren't present in the access token are ignored and the function continues with the next privilege or SID to find for filtering. For a fully deterministic outcome the caller is responsible for querying the information details of privileges and SIDs present in the token and then afterwards use such obtained information to do any kind of filtering to the token.

Definition at line 859 of file tokenlif.c.

{
    NTSTATUS Status;
    PTOKEN AccessToken;
    PVOID EndMem;
    ULONG DynamicPartSize;
    ULONG RestrictedSidsLength;
    ULONG PrivilegesLength;
    ULONG PrimaryGroupIndex;
    ULONG RestrictedSidsInList;
    ULONG RestrictedSidsInToken;
    ULONG VariableLength, TotalSize;
    ULONG PrivsInToken, PrivsInList;
    ULONG GroupsInToken, GroupsInList;
    BOOLEAN WantPrivilegesDisabled;
    BOOLEAN FoundPrivilege;
    BOOLEAN FoundGroup;
 
    PAGED_CODE();
 
    /* Ensure that the source token is valid, and lock it */
    ASSERT(Token);
    SepAcquireTokenLockShared(Token);
 
    /* Assume the caller doesn't want privileges disabled */
    WantPrivilegesDisabled = FALSE;
 
    /* Assume we haven't found anything */
    FoundPrivilege = FALSE;
    FoundGroup = FALSE;
 
    /*
     * Take the size that we need for filtered token
     * allocation based upon the existing access token
     * we've been given.
     */
    VariableLength = Token->VariableLength;
 
    if (RestrictedSidsIntoToken != NULL)
    {
        /*
         * If the caller provided a list of restricted SIDs
         * to be added onto the filtered access token then
         * we must compute the size which is the total space
         * of the current token and the length of the restricted
         * SIDs for the filtered token.
         */
        RestrictedSidsLength = RestrictedSidsCount * sizeof(SID_AND_ATTRIBUTES);
        RestrictedSidsLength += RtlLengthSidAndAttributes(RestrictedSidsCount, RestrictedSidsIntoToken);
        RestrictedSidsLength = ALIGN_UP_BY(RestrictedSidsLength, sizeof(PVOID));
 
        /*
         * The variable length of the token is not just
         * the actual space length of the existing token
         * but also the sum of the restricted SIDs length.
         */
        VariableLength += RestrictedSidsLength;
        TotalSize = FIELD_OFFSET(TOKEN, VariablePart) + VariableLength + RestrictedSidsLength;
    }
    else
    {
        /* Otherwise the size is of the actual current token */
        TotalSize = FIELD_OFFSET(TOKEN, VariablePart) + VariableLength;
    }
 
    /*
     * Compute how much size we need to allocate
     * the dynamic part of the newly duplicated
     * token.
     */
    DynamicPartSize = Token->DefaultDacl ? Token->DefaultDacl->AclSize : 0;
    DynamicPartSize += RtlLengthSid(Token->PrimaryGroup);
 
    /* Set up a filtered token object */
    Status = ObCreateObject(PreviousMode,
                            SeTokenObjectType,
                            NULL,
                            PreviousMode,
                            NULL,
                            TotalSize,
                            Token->DynamicCharged,
                            TotalSize,
                            (PVOID*)&AccessToken);
    if (!NT_SUCCESS(Status))
    {
        DPRINT1("SepPerformTokenFiltering(): Failed to create the filtered token object (Status 0x%lx)\n", Status);
 
        /* Unlock the source token and bail out */
        SepReleaseTokenLock(Token);
        return Status;
    }
 
    /* Initialize the token and begin filling stuff to it */
    RtlZeroMemory(AccessToken, TotalSize);
 
    /* Set up a lock for the new token */
    Status = SepCreateTokenLock(AccessToken);
    if (!NT_SUCCESS(Status))
        goto Quit;
 
    /* Allocate new IDs for the token */
    ExAllocateLocallyUniqueId(&AccessToken->TokenId);
    ExAllocateLocallyUniqueId(&AccessToken->ModifiedId);
 
    /* Copy the type and impersonation level from the token */
    AccessToken->TokenType = Token->TokenType;
    AccessToken->ImpersonationLevel = Token->ImpersonationLevel;
 
    /* Copy the immutable fields */
    AccessToken->TokenSource.SourceIdentifier = Token->TokenSource.SourceIdentifier;
    RtlCopyMemory(AccessToken->TokenSource.SourceName,
                  Token->TokenSource.SourceName,
                  sizeof(Token->TokenSource.SourceName));
 
    AccessToken->AuthenticationId = Token->AuthenticationId;
    AccessToken->ParentTokenId = Token->TokenId;
    AccessToken->OriginatingLogonSession = Token->OriginatingLogonSession;
    AccessToken->DynamicCharged = Token->DynamicCharged;
 
    AccessToken->ExpirationTime = Token->ExpirationTime;
 
    /* Copy the mutable fields */
    AccessToken->SessionId = Token->SessionId;
    AccessToken->TokenFlags = Token->TokenFlags & ~TOKEN_SESSION_NOT_REFERENCED;
 
    /* Reference the logon session */
    Status = SepRmReferenceLogonSession(&AccessToken->AuthenticationId);
    if (!NT_SUCCESS(Status))
    {
        /* We failed, bail out*/
        DPRINT1("SepPerformTokenFiltering(): Failed to reference the logon session (Status 0x%lx)\n", Status);
        AccessToken->TokenFlags |= TOKEN_SESSION_NOT_REFERENCED;
        goto Quit;
    }
 
    /* Insert the referenced logon session into the token */
    Status = SepRmInsertLogonSessionIntoToken(AccessToken);
    if (!NT_SUCCESS(Status))
    {
        /* Failed to insert the logon session into the token, bail out */
        DPRINT1("SepPerformTokenFiltering(): Failed to insert the logon session into token (Status 0x%lx)\n", Status);
        goto Quit;
    }
 
    /* Fill in token debug information */
#if DBG
    RtlCopyMemory(AccessToken->ImageFileName,
                  PsGetCurrentProcess()->ImageFileName,
                  min(sizeof(AccessToken->ImageFileName), sizeof(PsGetCurrentProcess()->ImageFileName)));
 
    AccessToken->ProcessCid = PsGetCurrentProcessId();
    AccessToken->ThreadCid = PsGetCurrentThreadId();
    AccessToken->CreateMethod = TOKEN_FILTER_METHOD;
#endif
 
    /* Assign the data that reside in the token's variable information area */
    AccessToken->VariableLength = VariableLength;
    EndMem = (PVOID)&AccessToken->VariablePart;
 
    /* Copy the privileges from the existing token */
    AccessToken->PrivilegeCount = 0;
    AccessToken->Privileges = NULL;
    if (Token->Privileges && (Token->PrivilegeCount > 0))
    {
        PrivilegesLength = Token->PrivilegeCount * sizeof(LUID_AND_ATTRIBUTES);
        PrivilegesLength = ALIGN_UP_BY(PrivilegesLength, sizeof(PVOID));
 
        /*
         * Ensure that the token can actually hold all
         * the privileges from the existing token.
         * Otherwise something's seriously wrong and
         * we've to guard ourselves.
         */
        ASSERT(VariableLength >= PrivilegesLength);
 
        AccessToken->PrivilegeCount = Token->PrivilegeCount;
        AccessToken->Privileges = EndMem;
        EndMem = (PVOID)((ULONG_PTR)EndMem + PrivilegesLength);
        VariableLength -= PrivilegesLength;
 
        RtlCopyMemory(AccessToken->Privileges,
                      Token->Privileges,
                      AccessToken->PrivilegeCount * sizeof(LUID_AND_ATTRIBUTES));
    }
 
    /* Copy the user and groups */
    AccessToken->UserAndGroupCount = 0;
    AccessToken->UserAndGroups = NULL;
    if (Token->UserAndGroups && (Token->UserAndGroupCount > 0))
    {
        AccessToken->UserAndGroupCount = Token->UserAndGroupCount;
        AccessToken->UserAndGroups = EndMem;
        EndMem = &AccessToken->UserAndGroups[AccessToken->UserAndGroupCount];
        VariableLength -= ((ULONG_PTR)EndMem - (ULONG_PTR)AccessToken->UserAndGroups);
 
        Status = RtlCopySidAndAttributesArray(AccessToken->UserAndGroupCount,
                                              Token->UserAndGroups,
                                              VariableLength,
                                              AccessToken->UserAndGroups,
                                              EndMem,
                                              &EndMem,
                                              &VariableLength);
        if (!NT_SUCCESS(Status))
        {
            DPRINT1("SepPerformTokenFiltering(): Failed to copy the groups into token (Status 0x%lx)\n", Status);
            goto Quit;
        }
    }
 
    /* Copy the restricted SIDs */
    AccessToken->RestrictedSidCount = 0;
    AccessToken->RestrictedSids = NULL;
    if (Token->RestrictedSids && (Token->RestrictedSidCount > 0))
    {
        AccessToken->RestrictedSidCount = Token->RestrictedSidCount;
        AccessToken->RestrictedSids = EndMem;
        EndMem = &AccessToken->RestrictedSids[AccessToken->RestrictedSidCount];
        VariableLength -= ((ULONG_PTR)EndMem - (ULONG_PTR)AccessToken->RestrictedSids);
 
        Status = RtlCopySidAndAttributesArray(AccessToken->RestrictedSidCount,
                                              Token->RestrictedSids,
                                              VariableLength,
                                              AccessToken->RestrictedSids,
                                              EndMem,
                                              &EndMem,
                                              &VariableLength);
        if (!NT_SUCCESS(Status))
        {
            DPRINT1("SepPerformTokenFiltering(): Failed to copy the restricted SIDs into token (Status 0x%lx)\n", Status);
            goto Quit;
        }
    }
 
    /*
     * Insert the restricted SIDs into the token on
     * the request by the caller.
     */
    if (RestrictedSidsIntoToken != NULL)
    {
        for (RestrictedSidsInList = 0; RestrictedSidsInList < RestrictedSidsCount; RestrictedSidsInList++)
        {
            /* Did the caller assign attributes to the restricted SIDs? */
            if (RestrictedSidsIntoToken[RestrictedSidsInList].Attributes != 0)
            {
                /* There mustn't be any attributes, bail out */
                DPRINT1("SepPerformTokenFiltering(): There mustn't be any attributes to restricted SIDs!\n");
                Status = STATUS_INVALID_PARAMETER;
                goto Quit;
            }
        }
 
        /*
         * Ensure that the token can hold the restricted SIDs
         * (the variable length is calculated at the beginning
         * of the routine call).
         */
        ASSERT(VariableLength >= RestrictedSidsLength);
 
        /*
         * Now let's begin inserting the restricted SIDs into the filtered
         * access token from the list the caller gave us.
         */
        AccessToken->RestrictedSidCount = RestrictedSidsCount;
        AccessToken->RestrictedSids = EndMem;
        EndMem = (PVOID)((ULONG_PTR)EndMem + RestrictedSidsLength);
        VariableLength -= RestrictedSidsLength;
 
        RtlCopyMemory(AccessToken->RestrictedSids,
                      RestrictedSidsIntoToken,
                      AccessToken->RestrictedSidCount * sizeof(SID_AND_ATTRIBUTES));
 
        /*
         * As we've copied the restricted SIDs into
         * the token, we must assign them the following
         * combination of attributes SE_GROUP_ENABLED,
         * SE_GROUP_ENABLED_BY_DEFAULT and SE_GROUP_MANDATORY.
         * With such attributes we estabilish that restricting
         * SIDs into the token are enabled for access checks.
         */
        for (RestrictedSidsInToken = 0; RestrictedSidsInToken < AccessToken->RestrictedSidCount; RestrictedSidsInToken++)
        {
            AccessToken->RestrictedSids[RestrictedSidsInToken].Attributes |= (SE_GROUP_ENABLED | SE_GROUP_ENABLED_BY_DEFAULT | SE_GROUP_MANDATORY);
        }
 
        /*
         * As we added restricted SIDs into the token, mark
         * it as restricted.
         */
        AccessToken->TokenFlags |= TOKEN_IS_RESTRICTED;
    }
 
    /* Search for the primary group */
    Status = SepFindPrimaryGroupAndDefaultOwner(AccessToken,
                                                Token->PrimaryGroup,
                                                NULL,
                                                &PrimaryGroupIndex,
                                                NULL);
    if (!NT_SUCCESS(Status))
    {
        DPRINT1("SepPerformTokenFiltering(): Failed searching for the primary group (Status 0x%lx)\n", Status);
        goto Quit;
    }
 
    /* Now allocate the token's dynamic information area and set the data */
    AccessToken->DynamicPart = ExAllocatePoolWithTag(PagedPool,
                                                     DynamicPartSize,
                                                     TAG_TOKEN_DYNAMIC);
    if (AccessToken->DynamicPart == NULL)
    {
        Status = STATUS_INSUFFICIENT_RESOURCES;
        goto Quit;
    }
 
    /* Unused memory in the dynamic area */
    AccessToken->DynamicAvailable = 0;
 
    /*
     * Assign the primary group to the token
     * and put it in the dynamic part as well.
     */
    EndMem = (PVOID)AccessToken->DynamicPart;
    AccessToken->PrimaryGroup = EndMem;
    RtlCopySid(RtlLengthSid(AccessToken->UserAndGroups[PrimaryGroupIndex].Sid),
                            EndMem,
                            AccessToken->UserAndGroups[PrimaryGroupIndex].Sid);
    AccessToken->DefaultOwnerIndex = Token->DefaultOwnerIndex;
    EndMem = (PVOID)((ULONG_PTR)EndMem + RtlLengthSid(AccessToken->UserAndGroups[PrimaryGroupIndex].Sid));
 
    /*
     * The existing token has a default DACL only
     * if it has an allocated dynamic part.
     */
    if (Token->DynamicPart && Token->DefaultDacl)
    {
        AccessToken->DefaultDacl = EndMem;
 
        RtlCopyMemory(EndMem,
                      Token->DefaultDacl,
                      Token->DefaultDacl->AclSize);
    }
 
    /*
     * Now figure out what does the caller
     * want with the privileges.
     */
    if (PrivilegeFlags & DISABLE_MAX_PRIVILEGE)
    {
        /*
         * The caller wants them disabled, cache this request
         * for later operations.
         */
        WantPrivilegesDisabled = TRUE;
    }
 
    if (PrivilegeFlags & SANDBOX_INERT)
    {
        /* The caller wants an inert token, store the TOKEN_SANDBOX_INERT flag now */
        AccessToken->TokenFlags |= TOKEN_SANDBOX_INERT;
    }
 
    /*
     * Now it's time to filter the token's privileges.
     * Loop all the privileges in the token.
     */
    for (PrivsInToken = 0; PrivsInToken < AccessToken->PrivilegeCount; PrivsInToken++)
    {
        if (WantPrivilegesDisabled)
        {
            /*
             * We got the acknowledgement that the caller wants
             * to disable all the privileges so let's just do it.
             * However, as per the general documentation is stated
             * that only SE_CHANGE_NOTIFY_PRIVILEGE must be kept
             * therefore in that case we must skip this privilege.
             */
            if (AccessToken->Privileges[PrivsInToken].Luid.LowPart == SE_CHANGE_NOTIFY_PRIVILEGE)
            {
                continue;
            }
            else
            {
                /*
                 * The act of disabling privileges actually means
                 * "deleting" them from the access token entirely.
                 * First we must disable them so that we can update
                 * token flags accordingly.
                 */
                AccessToken->Privileges[PrivsInToken].Attributes &= ~SE_PRIVILEGE_ENABLED;
                SepUpdateSinglePrivilegeFlagToken(AccessToken, PrivsInToken);
 
                /* Remove the privileges now */
                SepRemovePrivilegeToken(AccessToken, PrivsInToken);
                PrivsInToken--;
            }
        }
        else
        {
            if (PrivilegesToBeDeleted != NULL)
            {
                /* Loop the privileges we've got to delete */
                for (PrivsInList = 0; PrivsInList < PrivilegesCount; PrivsInList++)
                {
                    /* Does this privilege exist in the token? */
                    if (RtlEqualLuid(&AccessToken->Privileges[PrivsInToken].Luid,
                                     &PrivilegesToBeDeleted[PrivsInList].Luid))
                    {
                        /* Mark that we found it */
                        FoundPrivilege = TRUE;
                        break;
                    }
                }
 
                /* Did we find the privilege? */
                if (PrivsInList == PrivilegesCount)
                {
                    /* We didn't, continue with next one */
                    continue;
                }
            }
        }
 
        /*
         * If we have found the target privilege in the token
         * based on the privileges list given by the caller
         * then begin deleting it.
         */
        if (FoundPrivilege)
        {
            /* Disable the privilege and update the flags */
            AccessToken->Privileges[PrivsInToken].Attributes &= ~SE_PRIVILEGE_ENABLED;
            SepUpdateSinglePrivilegeFlagToken(AccessToken, PrivsInToken);
 
            /* Delete the privilege */
            SepRemovePrivilegeToken(AccessToken, PrivsInToken);
 
            /*
             * Adjust the index and reset the FoundPrivilege indicator
             * so that we can continue with the next privilege to delete.
             */
            PrivsInToken--;
            FoundPrivilege = FALSE;
            continue;
        }
    }
 
    /*
     * Loop the group SIDs that we want to disable as
     * per on the request by the caller.
     */
    if (SidsToBeDisabled != NULL)
    {
        for (GroupsInToken = 0; GroupsInToken < AccessToken->UserAndGroupCount; GroupsInToken++)
        {
            for (GroupsInList = 0; GroupsInList < RegularGroupsSidCount; GroupsInList++)
            {
                /* Does this group SID exist in the token? */
                if (RtlEqualSid(&AccessToken->UserAndGroups[GroupsInToken].Sid,
                                &SidsToBeDisabled[GroupsInList].Sid))
                {
                    /* Mark that we found it */
                    FoundGroup = TRUE;
                    break;
                }
            }
 
            /* Did we find the group? */
            if (GroupsInList == RegularGroupsSidCount)
            {
                /* We didn't, continue with next one */
                continue;
            }
 
            /* If we have found the group, disable it */
            if (FoundGroup)
            {
                /*
                 * If the acess token belongs to the administrators
                 * group and this is the target group, we must take
                 * away TOKEN_HAS_ADMIN_GROUP flag from the token.
                 */
                if (RtlEqualSid(SeAliasAdminsSid,
                                &AccessToken->UserAndGroups[GroupsInToken].Sid))
                {
                    AccessToken->TokenFlags &= ~TOKEN_HAS_ADMIN_GROUP;
                }
 
                /*
                 * If the target group that we have found it is the
                 * owner then from now on it no longer is but the user.
                 * Therefore assign the default owner index as the user.
                 */
                if (AccessToken->DefaultOwnerIndex == GroupsInToken)
                {
                    AccessToken->DefaultOwnerIndex = 0;
                }
 
                /*
                 * The principle of disabling a group SID is by
                 * taking away SE_GROUP_ENABLED_BY_DEFAULT and
                 * SE_GROUP_ENABLED attributes and assign
                 * SE_GROUP_USE_FOR_DENY_ONLY. This renders
                 * SID a "Deny only" SID.
                 */
                AccessToken->UserAndGroups[GroupsInToken].Attributes &= ~(SE_GROUP_ENABLED | SE_GROUP_ENABLED_BY_DEFAULT);
                AccessToken->UserAndGroups[GroupsInToken].Attributes |= SE_GROUP_USE_FOR_DENY_ONLY;
 
                /* Adjust the index and continue with the next group */
                GroupsInToken--;
                FoundGroup = FALSE;
                continue;
            }
        }
    }
 
    /* We've finally filtered the token, return it to the caller */
    *FilteredToken = AccessToken;
    Status = STATUS_SUCCESS;
    DPRINT("SepPerformTokenFiltering(): The token has been filtered!\n");
 
Quit:
    if (!NT_SUCCESS(Status))
    {
        /* Dereference the created token */
        ObDereferenceObject(AccessToken);
    }
 
    /* Unlock the source token */
    SepReleaseTokenLock(Token);
 
    return Status;
}

Referenced by NtFilterToken(), and SeFilterToken().