[ros-diffs] [reactos] 03/07: [NTOSKRNL] Implement support for device maps in ObpLookupObjectName

[Pierre Schweitzer]

https://git.reactos.org/?p=reactos.git;a=commitdiff;h=f13b6e025f89096cee0d2…

commit f13b6e025f89096cee0d224b3d258f75ba356d3d
Author:     Pierre Schweitzer <pierre(a)reactos.org>
AuthorDate: Thu Jun 20 08:55:31 2019 +0200
Commit:     Pierre Schweitzer <pierre(a)reactos.org>
CommitDate: Sun Jun 30 23:07:54 2019 +0200

    [NTOSKRNL] Implement support for device maps in ObpLookupObjectName
    
    This allows getting rid of the ?? hack in the kernel but this doesn't
    allow enabling LUID device maps as ReactOS can no longer open a
    session with them enabled. So, we must remain with device maps at
    root
    
    CORE-16114
---
 ntoskrnl/include/internal/ob.h |  6 ++++
 ntoskrnl/ob/obname.c           | 67 ++++++++++++++++++++++++++----------------
 2 files changed, 48 insertions(+), 25 deletions(-)

diff --git a/ntoskrnl/include/internal/ob.h b/ntoskrnl/include/internal/ob.h
index 266c4dd668c..41e1af894a9 100644
--- a/ntoskrnl/include/internal/ob.h
+++ b/ntoskrnl/include/internal/ob.h
@@ -443,6 +443,12 @@ ObIsLUIDDeviceMapsEnabled(
     VOID
 );
 
+PDEVICE_MAP
+NTAPI
+ObpReferenceDeviceMap(
+    VOID
+);
+
 //
 // Security descriptor cache functions
 //
diff --git a/ntoskrnl/ob/obname.c b/ntoskrnl/ob/obname.c
index 460338f0d48..9ba15a6d013 100644
--- a/ntoskrnl/ob/obname.c
+++ b/ntoskrnl/ob/obname.c
@@ -214,26 +214,6 @@ ObpCreateDosDevicesDirectory(VOID)
     if (!NT_SUCCESS(Status))
         goto done;
 
-    /*********************************************\
-    |*** HACK until we support device mappings ***|
-    |*** Add a symlink \??\ <--> \GLOBAL??\    ***|
-    \*********************************************/
-    RtlInitUnicodeString(&LinkName, L"\\??");
-    InitializeObjectAttributes(&ObjectAttributes,
-                               &LinkName,
-                               OBJ_PERMANENT,
-                               NULL,
-                               &DosDevicesSD);
-    Status = NtCreateSymbolicLinkObject(&SymHandle,
-                                        SYMBOLIC_LINK_ALL_ACCESS,
-                                        &ObjectAttributes,
-                                        &RootName);
-    if (NT_SUCCESS(Status)) NtClose(SymHandle);
-    /*********************************************\
-    \*********************************************/
-
-    // FIXME: Create a device mapping for the global \?? directory
-
     /*
      * Initialize the \??\GLOBALROOT symbolic link
      * pointing to the root directory \ .
@@ -490,6 +470,8 @@ ObpLookupObjectName(IN HANDLE RootHandle OPTIONAL,
     PWCHAR NewName;
     POBJECT_HEADER_NAME_INFO ObjectNameInfo;
     ULONG MaxReparse = 30;
+    PDEVICE_MAP DeviceMap = NULL;
+    UNICODE_STRING LocalName;
     PAGED_CODE();
     OBTRACE(OB_NAMESPACE_DEBUG,
             "%s - Finding Object: %wZ. Expecting: %p\n",
@@ -642,6 +624,8 @@ ObpLookupObjectName(IN HANDLE RootHandle OPTIONAL,
             *FoundObject = Object;
             return Status;
         }
+
+        LocalName = *ObjectName;
     }
     else
     {
@@ -695,7 +679,14 @@ ObpLookupObjectName(IN HANDLE RootHandle OPTIONAL,
         else
         {
 ParseFromRoot:
-            /* FIXME: Check if we have a device map */
+            LocalName = *ObjectName;
+
+            /* Deference the device map if we already have one */
+            if (DeviceMap != NULL)
+            {
+                ObfDereferenceDeviceMap(DeviceMap);
+                DeviceMap = NULL;
+            }
 
             /* Check if this is a possible DOS name */
             if (!((ULONG_PTR)(ObjectName->Buffer) & 7))
@@ -713,7 +704,17 @@ ParseFromRoot:
                     (*(PULONGLONG)(ObjectName->Buffer) ==
                      ObpDosDevicesShortNamePrefix.Alignment.QuadPart))
                 {
-                    /* FIXME! */
+                    DeviceMap = ObpReferenceDeviceMap();
+                    /* We have a local mapping, drop the ?? prefix */
+                    if (DeviceMap != NULL && DeviceMap->DosDevicesDirectory !=
NULL)
+                    {
+                        LocalName.Length -= ObpDosDevicesShortName.Length;
+                        LocalName.MaximumLength -= ObpDosDevicesShortName.Length;
+                        LocalName.Buffer += (ObpDosDevicesShortName.Length /
sizeof(WCHAR));
+
+                        /* We'll browse that local directory */
+                        Directory = DeviceMap->DosDevicesDirectory;
+                    }
                 }
                 else if ((ObjectName->Length == ObpDosDevicesShortName.Length -
                                                 sizeof(WCHAR)) &&
@@ -722,7 +723,23 @@ ParseFromRoot:
                          (*((PWCHAR)(ObjectName->Buffer) + 2) ==
                           (WCHAR)(ObpDosDevicesShortNameRoot.Alignment.HighPart)))
                 {
-                    /* FIXME! */
+                    DeviceMap = ObpReferenceDeviceMap();
+
+                    /* Caller is looking for the directory itself */
+                    if (DeviceMap != NULL && DeviceMap->DosDevicesDirectory !=
NULL)
+                    {
+                        Status =
ObReferenceObjectByPointer(DeviceMap->DosDevicesDirectory,
+                                                            0,
+                                                            ObjectType,
+                                                            AccessMode);
+                        if (NT_SUCCESS(Status))
+                        {
+                            *FoundObject = DeviceMap->DosDevicesDirectory;
+                        }
+
+                        ObfDereferenceDeviceMap(DeviceMap);
+                        return Status;
+                    }
                 }
             }
         }
@@ -740,7 +757,7 @@ ParseFromRoot:
     while (Reparse && MaxReparse)
     {
         /* Get the name */
-        RemainingName = *ObjectName;
+        RemainingName = LocalName;
 
         /* Disable reparsing again */
         Reparse = FALSE;
@@ -1149,7 +1166,7 @@ ReparseObject:
     }
 
     /* Check if we have a device map and dereference it if so */
-    //if (DeviceMap) ObfDereferenceDeviceMap(DeviceMap);
+    if (DeviceMap) ObfDereferenceDeviceMap(DeviceMap);
 
     /* Check if we have a referenced directory and dereference it if so */
     if (ReferencedDirectory) ObDereferenceObject(ReferencedDirectory);