01/02: [NTOSKRNL] When checking for byte offset alignment, tolerate some magic values

[Pierre Schweitzer]

https://git.reactos.org/?p=reactos.git;a=commitdiff;h=1bd25c5c24047c5d6e4c3…

commit 1bd25c5c24047c5d6e4c387386c38073d551d827
Author:     Pierre Schweitzer <pierre(a)reactos.org>
AuthorDate: Thu Oct 4 07:53:12 2018 +0200
Commit:     Pierre Schweitzer <pierre(a)reactos.org>
CommitDate: Thu Oct 4 07:53:12 2018 +0200

    [NTOSKRNL] When checking for byte offset alignment, tolerate some magic values
---
 ntoskrnl/io/iomgr/iofunc.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/ntoskrnl/io/iomgr/iofunc.c b/ntoskrnl/io/iomgr/iofunc.c
index c344b422d8..f3ad7164c2 100644
--- a/ntoskrnl/io/iomgr/iofunc.c
+++ b/ntoskrnl/io/iomgr/iofunc.c
@@ -3656,9 +3656,15 @@ NtWriteFile(IN HANDLE FileHandle,
                     if ((DeviceObject->SectorSize != 0) &&
                         (ByteOffset->QuadPart % DeviceObject->SectorSize != 0))
                     {
-                        /* Release the file object and and fail */
-                        ObDereferenceObject(FileObject);
-                        return STATUS_INVALID_PARAMETER;
+                        /* Only if that's not specific values for synchronous IO */
+                        if ((ByteOffset->QuadPart != FILE_WRITE_TO_END_OF_FILE)
&&
+                            (ByteOffset->QuadPart != FILE_USE_FILE_POINTER_POSITION
||
+                             !BooleanFlagOn(FileObject->Flags, FO_SYNCHRONOUS_IO)))
+                        {
+                            /* Release the file object and and fail */
+                            ObDereferenceObject(FileObject);
+                            return STATUS_INVALID_PARAMETER;
+                        }
                     }
                 }
             }