[libvirt] [PATCH v5 17/20] tpm: Pass migration key passphrase via fd to swtpm

[Stefan Berger]

On 7/25/19 5:58 AM, Daniel P. Berrangé wrote:
> On Fri, Jul 12, 2019 at 12:23:51PM -0400, Stefan Berger wrote:
>> This patch now passes the passphrase as a migration key to swtpm.
>> This now encrypts the state of the TPM while a VM is migrated between
>> hosts or when suspended into a file. Since the migration key secret
>> is the same as the state encryption secret, this now requires that
>> the migration destination host has the same secret value.
>>
>> Signed-off-by: Stefan Berger <stefanb at linux.ibm.com>
>> ---
>>   src/qemu/qemu_tpm.c | 10 ++++++++++
>>   1 file changed, 10 insertions(+)
>
>> @@ -651,6 +655,12 @@ qemuTPMEmulatorBuildCommand(virDomainTPMDefPtr tpm,
>>                                  pwdfile_fd);
>>           virCommandPassFD(cmd, pwdfile_fd, VIR_COMMAND_PASS_FD_CLOSE_PARENT);
>>           pwdfile_fd = -1;
>> +
>> +        virCommandAddArg(cmd, "--migration-key");
>> +        virCommandAddArgFormat(cmd, "pwdfd=%d,mode=aes-256-cbc,kdf=pbkdf2",
>> +                               migpwdfile_fd);
> Why do we have to specify a kdf for migration, but not for the original
> on disk encryoptiuon ?


swtpm_setup doesn't have it, but it's the default. Let me remove it.


>
>> +        virCommandPassFD(cmd, migpwdfile_fd, VIR_COMMAND_PASS_FD_CLOSE_PARENT);
>> +        migpwdfile_fd = -1;
> Reviewed-by: Daniel P. Berrangé <berrange at redhat.com>
>
>
> Regards,
> Daniel