mail_crypt plugin, few questions

[Aki Tuomi]

On 06.11.2017 13:20, Zbyszek Żółkiewski wrote:
>
>> Wiadomość napisana przez Aki Tuomi <aki.tuomi at dovecot.fi> w dniu 06.11.2017, o godz. 08:44:
>>
>> On 04.11.2017 20:52, Zbyszek Żółkiewski wrote:
>>> Hi,
>>>
>>> I have few questions regarding mail_crypt:
>>>
>>> 1) Is mail_crypt_global_private_key file read upon dovecot start/restart only or it is/can be read in any other time? I have made few tests by starting dovecot and removing master key for decryption - therefore it is not available on the platform - it only reside in memory, removing one of attack vectors
>> It can be given from config file, or from user database. It is read on
>> use. You can also encrypt the key using a password, but in the end, the
>> password or the key needs to be provided by something.
>
> yes i am loading it in conf file like: 
>
> mail_crypt_global_private_key = </etc/dovecot/somefile.key 
>
> but then i am removing that file - and it looks like dovecot still is able to decrypt mails encrypted with that file. So you are saying there might be situation that this file need to be “re-read” from disk ? 
Yeah, the file content is loaded into configuration. If you need to
re-read it you need to restart dovecot.

>
>>> 3) is there any better way to encrypt mails that were sent before enabling mail_crypt ? I have made some simple script to automate and in-place encryption: https://gist.github.com/kolargol/d551d132949068ce6efce7bc85a317cb but maybe there is better way? If someone want to use it, please read code before as it require updating magic(5) local database
>>>
>>> thanks!
>> The Best Practice, supported way, is to move the emails around, so you
>> move all your mails from INBOX to FooBox, and then back. This can have
>> some side-effects, and you might want to test this. Most notably it will
>> consume UIDs, unless you reset the folder by removing indexes.
> ok, i was using above script to encrypt hundred of thousands email files and i did not found any issues, it is also quite fast, do you see any problems with that ? 
>
> thanks!
>
> _
> Zbyszek

That script looks fine.

Aki