Kernel - Lock Fcb during setFileInfo notify report change

Author: Liryna

sys/fileinfo.c

@@ -797,6 +797,8 @@ VOID DokanCompleteSetInformation(__in PREQUEST_CONTEXT RequestContext,
                                  __in PEVENT_INFORMATION EventInfo) {
   PDokanCCB ccb;
   PDokanFCB fcb = NULL;
+  BOOLEAN fcbLocked = TRUE;
+  UNICODE_STRING oldFileName;
   FILE_INFORMATION_CLASS infoClass;
 
   RequestContext->Irp->IoStatus.Information = EventInfo->BufferLength;
@@ -805,6 +807,9 @@ VOID DokanCompleteSetInformation(__in PREQUEST_CONTEXT RequestContext,
   ccb = RequestContext->IrpSp->FileObject->FsContext2;
   ASSERT(ccb != NULL);
 
+  fcb = ccb->Fcb;
+  ASSERT(fcb != NULL);
+
   infoClass = RequestContext->IrpSp->Parameters.SetFile.FileInformationClass;
   DOKAN_LOG_FINE_IRP(RequestContext, "FileObject=%p infoClass=%s",
                      RequestContext->IrpSp->FileObject,
@@ -816,30 +821,17 @@ VOID DokanCompleteSetInformation(__in PREQUEST_CONTEXT RequestContext,
     return;
   }
 
-  fcb = ccb->Fcb;
-  ASSERT(fcb != NULL);
-
-  switch (RequestContext->IrpSp->Parameters.SetFile.FileInformationClass) {
-  case FileAllocationInformation:
-    DokanNotifyReportChange(RequestContext, fcb, FILE_NOTIFY_CHANGE_SIZE,
-                            FILE_ACTION_MODIFIED);
-    break;
-  case FileBasicInformation:
-    DokanNotifyReportChange(
-        RequestContext, fcb,
-        FILE_NOTIFY_CHANGE_ATTRIBUTES | FILE_NOTIFY_CHANGE_LAST_WRITE |
-            FILE_NOTIFY_CHANGE_LAST_ACCESS | FILE_NOTIFY_CHANGE_CREATION,
-        FILE_ACTION_MODIFIED);
-    break;
+  // Process changes
+  switch (infoClass) {
   case FileDispositionInformation:
   case FileDispositionInformationEx: {
+    // Note that we do not acquire the resource for paging file
+    // operations in order to avoid deadlock with Mm
+    fcbLocked = !(RequestContext->Irp->Flags & IRP_PAGING_IO);
+    if (fcbLocked) {
+      DokanFCBLockRW(fcb);
+    }
     if (EventInfo->Operation.Delete.DeleteOnClose) {
-      // Note that we do not acquire the resource for paging file
-      // operations in order to avoid deadlock with Mm
-      BOOLEAN fcbLocked = !(RequestContext->Irp->Flags & IRP_PAGING_IO);
-      if (fcbLocked) {
-        DokanFCBLockRW(fcb);
-      }
       if (!MmFlushImageSection(&fcb->SectionObjectPointers, MmFlushForDelete)) {
         DOKAN_LOG_FINE_IRP(RequestContext, "Cannot delete user mapped image");
         RequestContext->Irp->IoStatus.Status = STATUS_CANNOT_DELETE;
@@ -849,53 +841,76 @@ VOID DokanCompleteSetInformation(__in PREQUEST_CONTEXT RequestContext,
         DOKAN_LOG_FINE_IRP(RequestContext, "FileObject->DeletePending = TRUE");
         RequestContext->IrpSp->FileObject->DeletePending = TRUE;
       }
-      if (fcbLocked) {
-        DokanFCBUnlock(fcb);
-      }
+
     } else {
       DokanCCBFlagsClearBit(ccb, DOKAN_DELETE_ON_CLOSE);
       DokanFCBFlagsClearBit(fcb, DOKAN_DELETE_ON_CLOSE);
       DOKAN_LOG_FINE_IRP(RequestContext, "FileObject->DeletePending = FALSE");
       RequestContext->IrpSp->FileObject->DeletePending = FALSE;
     }
-    if (RequestContext->IrpSp->FileObject->DeletePending) {
-      if (DokanFCBFlagsIsSet(fcb, DOKAN_FILE_DIRECTORY)) {
-        DokanNotifyReportChange(RequestContext, fcb,
-                                FILE_NOTIFY_CHANGE_DIR_NAME,
-                                FILE_ACTION_REMOVED);
-      } else {
-        DokanNotifyReportChange(RequestContext, fcb,
-                                FILE_NOTIFY_CHANGE_FILE_NAME,
-                                FILE_ACTION_REMOVED);
-      }
-    }
-  } break;
-  case FileEndOfFileInformation:
-    DokanNotifyReportChange(RequestContext, fcb, FILE_NOTIFY_CHANGE_SIZE,
-                            FILE_ACTION_MODIFIED);
     break;
-  case FileRenameInformationEx:
-  case FileRenameInformation: {
+  }
+  case FileRenameInformation:
+  case FileRenameInformationEx: {
+    DokanVCBLockRW(RequestContext->Vcb);
     DokanFCBLockRW(fcb);
     // Process rename
-    UNICODE_STRING oldFileName =
+    oldFileName =
         DokanWrapUnicodeString(fcb->FileName.Buffer, fcb->FileName.Length);
     // Copy new file name
     PVOID buffer = DokanAllocZero(EventInfo->BufferLength + sizeof(WCHAR));
     if (buffer == NULL) {
       RequestContext->Irp->IoStatus.Status = STATUS_INSUFFICIENT_RESOURCES;
       DokanFCBUnlock(fcb);
+      DokanVCBUnlock(RequestContext->Vcb);
       return;
     }
     RtlCopyMemory(buffer, EventInfo->Buffer, EventInfo->BufferLength);
-    DokanVCBLockRW(RequestContext->Vcb);
     DokanRenameFcb(RequestContext, fcb, buffer,
                    (USHORT)EventInfo->BufferLength);
     DokanVCBUnlock(RequestContext->Vcb);
     DOKAN_LOG_FINE_IRP(RequestContext, "Fcb=%p renamed \"%wZ\"", fcb,
                        &fcb->FileName);
-    DokanFCBUnlock(fcb);
-    // Notify rename
+    break;
+  }
+  default:
+    DokanFCBLockRO(fcb);
+    break;
+  }
+
+  // Notify changes
+  switch (infoClass) {
+  case FileAllocationInformation:
+    DokanNotifyReportChange(RequestContext, fcb, FILE_NOTIFY_CHANGE_SIZE,
+                            FILE_ACTION_MODIFIED);
+    break;
+  case FileBasicInformation:
+    DokanNotifyReportChange(
+        RequestContext, fcb,
+        FILE_NOTIFY_CHANGE_ATTRIBUTES | FILE_NOTIFY_CHANGE_LAST_WRITE |
+            FILE_NOTIFY_CHANGE_LAST_ACCESS | FILE_NOTIFY_CHANGE_CREATION,
+        FILE_ACTION_MODIFIED);
+    break;
+  case FileDispositionInformation:
+  case FileDispositionInformationEx:
+    if (RequestContext->IrpSp->FileObject->DeletePending) {
+      if (DokanFCBFlagsIsSet(fcb, DOKAN_FILE_DIRECTORY)) {
+        DokanNotifyReportChange(RequestContext, fcb,
+                                FILE_NOTIFY_CHANGE_DIR_NAME,
+                                FILE_ACTION_REMOVED);
+      } else {
+        DokanNotifyReportChange(RequestContext, fcb,
+                                FILE_NOTIFY_CHANGE_FILE_NAME,
+                                FILE_ACTION_REMOVED);
+      }
+    }
+    break;
+  case FileEndOfFileInformation:
+    DokanNotifyReportChange(RequestContext, fcb, FILE_NOTIFY_CHANGE_SIZE,
+                            FILE_ACTION_MODIFIED);
+    break;
+  case FileRenameInformation:
+  case FileRenameInformationEx: {
     if (IsInSameDirectory(&oldFileName, &fcb->FileName)) {
       DokanNotifyReportChange0(RequestContext, fcb, &oldFileName,
                                DokanFCBFlagsIsSet(fcb, DOKAN_FILE_DIRECTORY)
@@ -927,4 +942,7 @@ VOID DokanCompleteSetInformation(__in PREQUEST_CONTEXT RequestContext,
                             FILE_ACTION_MODIFIED);
     break;
   }
+  if (fcbLocked) {
+    DokanFCBUnlock(fcb);
+  }
 }