Access check is an expensive operation, that is, whenever an access to an
object is performed an access check has to be done to ensure the access
can be allowed to the calling thread who attempts to access such object.
Currently SepAnalyzeAcesFromDacl allocates a block of pool memory for
access check rights, nagging the Memory Manager like a desperate naughty
creep. So instead initialize the access rights as a simple variable in
SepAccessCheck and pass it out as an address to SepAnalyzeAcesFromDacl so
that the function will fill it up with access rights. This helps with
performance, avoiding wasting a few bits of memory just to hold these
access rights.
In addition to that, add a few asserts and fix the copyright header on
both se.h and accesschk.c, to reflect the Coding Style rules.
-- Rewrite PspChargeProcessQuotaSpecifiedPool and PspReturnProcessQuotaSpecifiedPool private kernel routines, with the goal to implement the algorithms necessary to manage the fields of quota blocks (Usage, Return, Limit and Peak).
-- Invoke the Mm if quota limit raising or returning has to be done
-- When destroying a quota block, make sure that we're giving back all the rest of non-returned quotas to Memory Mm
-- Crash the system with QUOTA_UNDERFLOW if someone is returning way too much quota than it was previously charged
-- When a process exits, ensure that it doesn't hold up any charged quotas in QuotaUsage field of the process object, that way we're enforcing proper kernel consistency
-- Implement PsChargeSharedPoolQuota and PsChargeProcessPageFileQuota functions, used exclusively by the Object Manager. These routines are used to charge or return amount of quotas of a newly created object.
-- On PspInheritQuota, when assigning to process the default quota block if no parent process is given, we must increment the reference counts as we're using it
-- Handle the ProcessCount reference field, as it wasn't used
-- Annotate the functions with SAL
-- Document the code
=== REMARKS ===
Windows LogOn (Winlogon) is responsible for setting up a different quota block for all the processes within an interactive session, which is what we don't do. What we're currently doing instead is we're using the default block, PspDefaultQuotaBlock, for all the processes
across the system. The default block contains the default limits of -1 (which would imply no limits). By definition, the kernel won't ever return STATUS_QUOTA_EXCEEDED as we literally don't set up a definite limit for regular processes. This situation has to be tackled
in the future.
=== TODO FOR FUTURE ===
Most of the code in PspChargeProcessQuotaSpecifiedPool and PspReturnProcessQuotaSpecifiedPool private routines must be refactored in order to reduce the usage of the quota spin lock, possibly wrapping such code in a loop and whatnot.
CORE-17784
We have a special file, tag.h, which serves as a place to store whatever kernel pool allocation tag yet we still have some tags sparse over the kernel code... So just re-group them in one unique place.
SIDs are variadic by nature which means their lengths can vary in a given amount of time and certain factors that allow for this happen. This also especially can lead to issues when capturing SIDs and attributes because SeCaptureSidAndAttributesArray might end up overwriting the buffer during the time it's been called.
Therefore when we're copying the SIDs, validate their lengths. In addition to that, update the documentation header accordingly and add some debug prints in code.
In Windows Server 2003 the lock is initialised on a per-token basis, that is, the lock resource is created in SepDuplicateToken() and SepCreateToken() functions. This ensures that the lock initialisation is done locally for the specific token thus avoiding the need of a global lock.
- Overhaul SepCreateToken() and SepDuplicateToken() so that they
implement the "variable information area" of the token, where
immutable lists of user & groups and privileges reside, and the
"dynamic information area" (allocated separately in paged pool),
where mutable data such as the token's default DACL is stored.
Perform the necessary adaptations in SepDeleteToken() and in
NtSetInformationToken().
- Actually dereference the token's logon session, when needed, in the
'TokenSessionReference' case in NtSetInformationToken().
- Overhaul SepFindPrimaryGroupAndDefaultOwner() so that it returns
the indices of candidate primary group and default owner within the
token's user & groups array. This allows for fixing the 'TokenOwner'
and 'TokenPrimaryGroup' cases of NtSetInformationToken(), since the
owner or primary group being set *MUST* already exist in the token's
user & groups array (as a by-product, memory corruptions that existed
before due to the broken way of setting these properties disappear too).
- Lock tokens every time operations are performed on them (NOTE: we
still use a global token lock!).
- Touch the ModifiedId LUID member of tokens everytime a write operation
(property change, etc...) is made on them.
- Fix some group attributes in the SYSTEM process token, SepCreateSystemProcessToken().
- Make the SeCreateTokenPrivilege mandatory when calling NtCreateToken().
- Update the token pool tags.
- Explicitly use the Ex*ResourceLite() versions of the locking functions
in the token locking macros.
