Co-authored-by: Victor Perevertkin <victor.perevertkin@reactos.org>
Introduce the initial changes needed to get other processors up and into kernel mode.
This only supports x86 as of now but is the first real step towards using other system processors.
Sometimes repairing a broken hive with a hive log does not always guarantee the hive
in question has fully recovered. In worst cases it could happen the LOG itself is even
corrupt too and that would certainly lead to a total unbootable system. This is most likely
if the victim hive is the SYSTEM hive.
This can be anyhow solved by the help of a mirror hive, or also called an "alternate hive".
Alternate hives serve the purpose as backup hives for primary hives of which there is still
a risk that is not worth taking. For now only the SYSTEM hive is granted the right to have
a backup alternate hive.
=== NOTE ===
Currently the SYSTEM hive can only base upon the alternate SYSTEM.ALT hive, which means the
corresponding LOG file never gets updated. When time comes the existing code must be adapted
to allow the possibility to use .ALT and .LOG hives simultaneously.
If FreeLdr performed recovery against the SYSTEM hive with a log, all of its data is only present in volatile memory thus dirty. So the kernel is responsible to flush all the data that's been recovered within the SYSTEM hive into the backing storage.
In addition to that, in some functions like CmFlushKey, CmSaveKey and CmSaveMergedKeys we must validate the underlying hives as a matter of precaution that everything is alright and we don't fuck all the shit up.
CmCheckRegistry is a function that provides the necessary validation checks for a registry hive. This function usually comes into action when logs have been replayed for example, or when a registry hive internals have changed such as when saving a key, loading a key, etc.
This commit implements the whole Check Registry infrastructure (cmcheck.c) in CMLIB library for ease of usage and wide accessibility across parts of the OS. In addition, two more functions for registry checks are also implemented -- HvValidateHive and HvValidateBin.
Instead of having the CmCheckRegistry implementation in the kernel, it's better to have it in the Configuration Manager library instead (aka CMLIB). The benefits of having it in the library are the following:
- CmCheckRegistry can be used in FreeLdr to fix the SYSTEM hive
- It can be used on-demand in the kernel
- It can be used for offline registry repair tools
- It makes the underlying CmCheckRegistry implementation code debug-able in user mode
CORE-9195
CORE-6762
During a I/O failure of whatever kind the upper-level driver, namely a FSD, can raise a hard error and a deadlock can occur. We wouldn't want that to happen for particular files like hives or logs so in such cases we must disable hard errors before toying with hives until we're done.
In addition to that, annotate the CmpFileSetSize function's parameters with SAL.
When shutting down the registry of the system we don't want that the registry in question gets poked again, such as flushing the hives or syncing the hives and respective logs for example. The reasoning behind this is very simple, during a complete shutdown the system does final check-ups and stuff until the computer
shuts down.
Any writing operations done to the registry can lead to erratic behaviors. CmShutdownSystem call already invokes a final flushing of all the hives on the backing storage which is more than enough to ensure consistency of the last session configuration. So after that final flushing, mark HvShutdownComplete as TRUE indicating
that any eventual flushing or syncying (in the case where HvSyncHive gets called) request is outright ignored.
NtSetDefaultLocale and ExpSetCurrentUserUILanguage do not probe the given locale or language ID,
and as a result of that these functions would happily take any given argument. This is problematic
because overwriting NLS data (specifically the Default registry key value as its gets set by the
NtSetDefaultLocale syscall itself) with garbage stuff, rendering the system completely unbootable.
In addition to that, these functions do not check the captured language/locale ID against pre-determined
locales or languages pre-installed in the system. This basically means an ID of 1, for example, is still
valid because it is not bogus albeit there is no such a locale of an ID of 1. That value would get passed
to the Default value key and that renders the system unbootable as well.
CORE-18100
- Stay attached while deleting the VAD node
- Acquire the appropriate working set lock when deleting a VAD node
- Both are needed for locking correctness
- Acquire the appropriate working set lock when calling MmLocateMemoryAreaByAddress
- Do not access MemoryArea without holding the lock (otherwise it can be pulled away under our feet)
- Fix range check for paged pool
These faults are handled by ARM³ and we don't need to check for a memory area. They can be recursive faults (e.g. from MiDeleteSystemPageableVm), so we might be holding the WS lock already. Passing it straight to ARM³ allows to acquire the WS lock below to look up the memory area.
Addendum to commit b3c55b9e6 (PR #4399).
Passing &CapturedObjectName as pointer to be probed and captured would
fail if e.g. PreviousMode == UserMode, since that pointer is always in
kernel space. Instead, pass the original user-mode pointer.
Bug caught by Timo Kreuzer ;)
This is a hack, because the kernel mode path can incur a recursive page fault with the AddressCreationLock acquired, which would lead to a recursive acquisition, once we do proper locking in MmAccessFault.
To properly fix this the PDE must be made valid, similar to the user mode path, but that is not that simple...
They can be spammy. Also clarify these debug prints, because some people
think that "failed to grant access rights" means there's something wrong
in the core access check functions.
Temporarily add the local group to the system token so that Virtualbox
GA services can properly set up network drives for shared folders.
What happens is that a security descriptor has a DACL with only one ACE
that grants access to Local SID (presumably coming from Vbox?)
but the client token is that of the service which is a SYSTEM token.
Perhaps we are not impersonating the right user or whatever else.
This is only a temporary placebo, until a proper solution is found.
CORE-18250
Certain apps such as AIM installer passes an empty generic mapping (this can
be understood with their generic masks set to 0) and our code tries to map
the access right from an ACE with the mapping provided by AccessCheck.
This can lead to a bug where we would not be able to decode the generic right
from an ACE as we need a proper generic mapping in order to do so. A mask
right that is not decoded it cannot be used to mask out the remaining rights,
further resulting into a denied access right.
What Windows does instead is they are mapping the ACE's rights in another place,
presumably when setting security data to an object, and they are using the
generic mapping passed by the kernel.
What we can do for the time being is to temporarily grant access to the client,
but only if they are an administrator.
CORE-18576
During an open or create procedure of a registry key, the registry parser grabs
a key control block (KCB) from the parser object and uses its information to do the
necessary work in order to obtain a pointer to the newly created or opened registry key.
However, the registry parsers faces several issues. First, we don't do subkey cache cleaning
information against gathered KCBs so whenever we do a registry parse we end up with KCBs
that have cache inconsistencies. Moreover we don't do any locking of whatever KCB we
are grabing during a parse procedure.
=== PROPOSED CHANGES ===
* Implement CmpComputeHashValue and CmpLookInCache functions. With CmpComputeHashValue we can
compute the convkey hashes of each subkey in the path name of a key so we can lock them
with CmpBuildAndLockKcbArray. CmpLookInCache is a function that searches for the suitable
KCB in the cache. The factors that determine if a KCB is "suitable" are:
-- the currently found KCB in the hash list has the same levels as that of the
given KCB from the parse object;
-- The key names from the computed hash values match with the block name of
the KCB;
-- The currently found KCB is not deleted.
The KCB will be changed if the key path name points to a partial match name in
the cache. The KCB from the parse object will be used if we have a full match
of remaining levels.
* Add missing CMP_LOCK_HASHES_FOR_KCB flags on CmpCreateKeyControlBlock calls
that create KCBs during a parse procedure. Such lock has to be preserved until
we're done with the registry parsing.
* On CmpDoCreateChild, preserve the exclusive lock of the KCB when we are
enlisting the key body.
* On CmpDoCreate, make sure that the passed parent KCB is locked exclusively and
lock the hiver flusher as we don't want the flusher to kick in during a key
creation on the given hive. Cleanup the subkey info when we're creating a key
object. Also implement missing cleanup path codes. Furthermore, avoid key
object creation if the parent KCB is protected with a read-only switch.
* Soft rewrite the CmpDoOpen function, namely how we manage a direct open vs
create KCB on open scenario. When a KCB is found in cache avoid touching
the key node. If the symbolic link has been resolved (aka found) then lock
exclusively the symbolic KCB. Otherwise just give the cached KCB to the caller.
If it were for the caller to request a KCB creation, we must check the passed
KCB from the parser object is locked exclusively, unlike on the case above
the caller doesn't want to create a KCB because there's already one in the cache.
We don't want anybody to touch our KCB while we are still toying with it during
its birth. Furthermore, enlist the key body but mind the kind of lock it's been
used.
* On CmpCreateLinkNode, avoid creating a key object if the parent KCB is protected
with a read-only switch. In addition, add missing hive flusher locks for both
the target hive and its child. Cleanup the subkey information of the KCB when
creating a link node, this ensures our cached KCB data remains consistent.
* Do a direct open on CmpParseKey if no remaining subkey levels have been found
during hash computation and cache lookup, in this case the given KCB is the
block that points to the exact key. This happens when for example someone tried
to call RegOpenKeyExW but submitting NULL to the lpSubKey argument parameter.
CORE-10581
ROSTESTS-198
CmpSecurityMethod is a method used by the Object Manager and called by this
subsystem whenever a security operation has to be done against a key object.
As CmpSecurityMethod is a specific OB construct we should not make any direct
call attempts to CmpSecurityMethod, only OB is responsible for that. This fixes
a deadlock where CmpSecurityMethod acquires a push lock for exclusive access
even though such lock is already acquired by the same calling thread in
CmpDoCreateChild.
This prevents a deadlock in DelistKeyBodyFromKCB when we delete a key
object because of an access check failure during a open procedure of a
registry key, as we are already holding a lock against the target KCB of
the key body.
Whenever a security request is invoked into a key object, such as when requesting
information from its security descriptor, the Object Manager will execute
the CmpSecurityMethod method to do the job.
The problem is that CmpSecurityMethod is not aware if the key control block
of the key body already has a lock acquired which means the function will attempt
to acquire a lock again, leading to a deadlock. This happens if the same
calling thread locks the KCB but it also wants to acquire security information
with ObCheckObjectAccess in CmpDoOpen.
Windows has a hack in CmpSecurityMethod where the passed KCB pointer is ORed
with a bitfield mask to avoid locking in all cases. This is ugly because it negates
every thread to acquire a lock if at least one has it.
The CmpUnLockKcbArray, CmpLockKcbArray and CmpBuildAndLockKcbArray routines
help us to lock KCBs within array so that information remains consistent when
we are doing a cache lookup during a parse procedure of the registry database.
Implement CmpBuildAndLockKcbArray and CmpUnLockKcbArray prototypes, we'll gonna need these
to do the locking/unlocking of KCBs stacked up in an array. In addition implement some CM
constructs specifically for cache lookup implementation (more at documentation remarks).
=== DOCUMENTATION REMARKS ===
CMP_SUBKEY_LEVELS_DEPTH_LIMIT -- This is the limit of up to 32 subkey levels
that the registry can permit. This is used in CmpComputeHashValue to ensure
that we don't compute more than the limit of subkeys we're allowed to.
CMP_KCBS_IN_ARRAY_LIMIT -- This is equal to CMP_SUBKEY_LEVELS_DEPTH_LIMIT
plus the addition by 2. This construct is used as a limit of KCB elements
the array can hold. 2 serves as an additional space for the array (one for
the root object and another one as extra space so we don't blow up the stack
array).
CMP_LOCK_KCB_ARRAY_EXCLUSIVE & CMP_LOCK_KCB_ARRAY_SHARED -- These flags are used exclusively
for CmpBuildAndLockKcbArray and CmpLockKcbArray. Their meaning are obvious.
CM_HASH_CACHE_STACK -- A structure used to store the hashes of KCBs for locking. It is named
"stack" because the way we store the hashes of KCBs is within an auxilliary "outer stack array".
CmpAcquireKcbLockSharedByKey can come in handy for use to lock KCBs by their convkey with a shared lock, specifically we would need this for cache lookup stuff.
- RtlpQuerySecurityDescriptor: Change argument type of first parameter from PISECURITY_DESCRIPTOR to PSECURITY_DESCRIPTOR, since it handles both absolute and self-relative SDs.
- RtlMakeSelfRelativeSD: rename first parameter from AbsoluteSD to SecurityDescriptor, since it handles both absolute and self-relative SDs.
- SepGetGroupFromDescriptor/SepGetOwnerFromDescriptor/SepGetDaclFromDescriptor/SepGetSaclFromDescriptor: Change parameter type from PVOID to PSECURITY_DESCRIPTOR for clarity.
