[dm-crypt] LUKS linux encrypted file system causing file corruption

Ralf Ramsauer ralf+dm at ramses-pyramidenbau.de
Mon Nov 30 13:47:47 CET 2015


Hi Sumit,

a change of the checksum implies that the source and destination file
differ. The reason why it differs is another question.
Does the checksum also differ if you copy it from unencrypted to
unencrypted?

First, please check your dmesg log if something suspicious occurs during
the copy process. A hard drive failure might also explain your problem.
As you're using VMs, check the dmesg of the hypervisor machine which
accesses the actual hardware.

Second, ensure that the source file is not changed during the copy
process and also not afterwards when comparing the checksums. Same
applies to the destination. You might want to use 'lsof' to check if
some process is accessing the file.

Just a guess - ...you mentioned VMs and a file of around 5GB... Sounds
like you're trying to copy a VM image, eh?
If so, make sure that your virtualization software does not touch the
file during copy.

Cheers
  Ralf

On 11/30/2015 10:19 AM, Sumit Kumar wrote:
> I am having a LUKS encrypted Linux file system (dmCrypt). When I copy
> a huge file, around 5 GB of file, from un-encrypted linux file system
> to LUKS encrypted linux file system then the target copied file MD5
> changed.
>
> I am not sure does it corrupting the file as the MD5 changed?
>
> I am using CentOS 6.5 and working on VMs not on physical machine.
>
> Any help will be greatly appreciated .
>
>
> -- 
> Thanks & Regards
> *Sumit Kumar*
>
>
> _______________________________________________
> dm-crypt mailing list
> dm-crypt at saout.de
> http://www.saout.de/mailman/listinfo/dm-crypt

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