[PATCH v4 06/11] ntoskrnl.exe: Make sure thread handle has rights to retrieve the TID.

[Derek Lesho]

Jacek says that duplicating and closing the sent handle in
kernel_object_from_handle every time would add unecessary overhead.

Signed-off-by: Derek Lesho 
---
 dlls/ntoskrnl.exe/ntoskrnl.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/dlls/ntoskrnl.exe/ntoskrnl.c b/dlls/ntoskrnl.exe/ntoskrnl.c
index 4685f3c394..1cfc1e1712 100644
--- a/dlls/ntoskrnl.exe/ntoskrnl.c
+++ b/dlls/ntoskrnl.exe/ntoskrnl.c
@@ -2487,6 +2487,7 @@ PEPROCESS WINAPI IoGetCurrentProcess(void)

static void *create_thread_object( HANDLE handle )
 {
+    NTSTATUS status;
     THREAD_BASIC_INFORMATION info;
     struct _KTHREAD *thread;

@@ -2495,8 +2496,20 @@ static void *create_thread_object( HANDLE handle )
     thread->header.Type = 6;
     thread->header.WaitListHead.Blink = INVALID_HANDLE_VALUE; /* mark as kernel object */

-    if (!NtQueryInformationThread( handle, ThreadBasicInformation, &info, sizeof(info), NULL ))
+    if (!(status = NtQueryInformationThread( handle, ThreadBasicInformation, &info, sizeof(info), NULL )))
         thread->id = info.ClientId;
+    else if (status == STATUS_ACCESS_DENIED)
+    {
+        HANDLE info_handle;
+
+        DuplicateHandle( GetCurrentProcess(), handle, GetCurrentProcess(),
+                    &info_handle, THREAD_QUERY_LIMITED_INFORMATION, FALSE, 0);
+
+        if (!NtQueryInformationThread( handle, ThreadBasicInformation, &info, sizeof(info), NULL ))
+            thread->id = info.ClientId;
+
+        NtClose( info_handle );
+    }

thread->critical_region = FALSE;

@@ -2526,7 +2539,7 @@ PRKTHREAD WINAPI KeGetCurrentThread(void)
         HANDLE handle = GetCurrentThread();

/* FIXME: we shouldn't need it, GetCurrentThread() should be client thread already */
-        if (GetCurrentThreadId() == request_thread) handle = OpenThread( 0, FALSE, client_tid );
+        if (GetCurrentThreadId() == request_thread) handle = OpenThread( THREAD_QUERY_LIMITED_INFORMATION, FALSE, client_tid );

kernel_object_from_handle( handle, PsThreadType, (void**)&thread );
         if (handle != GetCurrentThread()) NtClose( handle );