Shadow devices on .NET RC1

NTFSD
1

There is a bug in .NET RC1 that will cause bugcheck when “shadow” device
is used to open a file. The problem here is that IoMgr preserves VPB for
the device on which file is opening (NULL in case of the shadow device)
and then, after create IRP has been successfully handled, IoMgr compares
that preserved VPB with the one on which opened FileObject->Vpb actually
points. And if they are different (and they will be) IoMgr tries to
dereference preserved VPB without checking it for the NULL pointer. So, if
your shadow device doesn’t have a VPB it will blow up the system.

2

Note: this bug only affects .NET Server Release Candidate 1. Not any
prior released version of Windows Server.
It will be fixed for the next update to the .NET server release
candidate. If you believe this affects you in a major way for .NET
server RC1, please send mail to me.
Ravi

-----Original Message-----
From: xxxxx@Starbase.com
[mailto:xxxxx@Starbase.com]
Sent: Tuesday, September 17, 2002 11:13 AM
To: File Systems Developers
Subject: [ntfsd] Shadow devices on .NET RC1

There is a bug in .NET RC1 that will cause bugcheck when “shadow” device
is used to open a file. The problem here is that IoMgr preserves VPB for
the device on which file is opening (NULL in case of the shadow device)
and then, after create IRP has been successfully handled, IoMgr compares
that preserved VPB with the one on which opened FileObject->Vpb actually
points. And if they are different (and they will be) IoMgr tries to
dereference preserved VPB without checking it for the NULL pointer. So,
if your shadow device doesn’t have a VPB it will blow up the system.

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