RE: Re: 2.6.27.10: ata1.00: HPA detected: current 293044655, native 293046768

From: David Lethe
Date: Tue Dec 30 2008 - 13:14:36 EST


> -----Original Message-----
> From: linux-raid-owner@xxxxxxxxxxxxxxx [mailto:linux-raid-
> owner@xxxxxxxxxxxxxxx] On Behalf Of Robert Hancock
> Sent: Tuesday, December 30, 2008 11:30 AM
> To: linux-raid@xxxxxxxxxxxxxxx
> Cc: linux-ide@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> Subject: Re: 2.6.27.10: ata1.00: HPA detected: current 293044655,
> native 293046768
>
> Justin Piszcz wrote:
> > On one system, two Raptor 150s:
> >
> > [ 0.739402] ata1.00: HPA detected: current 293044655, native
> 293046768
> > [ 0.739491] ata1.00: ATA-7: WDC WD1500ADFD-00NLR5, 21.07QR5, max
> > UDMA/133
> > [ 0.739577] ata1.00: 293044655 sectors, multi 0: LBA48 NCQ (depth
> 31/32)
> > [ 0.742454] ata1.00: configured for UDMA/133
> >
> > [ 1.059146] ata2: SATA link up 1.5 Gbps (SStatus 113 SControl
300)
> > [ 1.061406] ata2.00: ATA-7: WDC WD1500ADFD-00NLR5, 21.07QR5, max
> > UDMA/133
> > [ 1.061494] ata2.00: 293046768 sectors, multi 0: LBA48 NCQ (depth
> 31/32)
> > [ 1.064360] ata2.00: configured for UDMA/133
> >
> > Two disks in a RAID-1 (mdadm) configuration, how come the first one
> > has an issue w/HPA as the firmware of both disks is the same..?
> >
> > l1:~# smartctl -a /dev/sda | grep -i bytes
> > User Capacity: 150,038,863,360 bytes
> > l1:~# smartctl -a /dev/sdb | grep -i bytes
> > User Capacity: 150,039,945,216 bytes
> > l1:~#
> >
> > Why does this occur?
>
> Presumably somebody or something set up a host protected area on one
> drive and not the other.. I believe there are some utilities out there
> that can be used to disable the HPA and allow the full capacity to be
> used.
>
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Warning - this hidden area could have been used to circumvent some
security, hold viruses,
steal data, whatever. I have unfortunately seen this trick more times
than I care to
get into.

If this disk drive is installed on a computer where such things are
a possibility, then I suggest bringing system down to single user mode,
having a witness
by your side, then resizing the disk and using dd to grab contents of
the "new" blocks,
so you can inspect it.

With the right software, and access to the sg driver, then one can
easily use this area as
their own private repository to keep stuff until the opportunity
presents itself to take
the data offsite.

FYI, there is no way to prevent somebody from resizing disk in this way
if they can write
to the sg driver, some of our customers use our software to resize in
this way and to monitor
changes, but you can really just set up a shell script to do this
yourself.

David
http://www.santools.com/smart/unix/manual



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