[Dovecot] Order of istream and ostream chains

[Philipp Brüll]

On 11/02/14 21:32, Timo Sirainen wrote:
> On 12.2.2014, at 2.27, Philipp Brüll <philippbruell at gmail.com> wrote:
>
>> I'm creating a scrambler plugin, that adds an istream and an ostream to the stream-chain for the mail input/output. It works well until the zlib plugin is added to the configuration. The scrambler should run before the zlib and encrypt the mail before it's compressed. Since, the plugin is named lib18_scrambler_... (and the other lib20_zlib....), that works well when a mail is received.
>>
>> When a mail is read via IMAP, the plugins should handle the mail in the reverse order. So first, the zlib should decompress it and afterwards the scrambler should decrypt it.
>>
>> But it seems, that they work the other way around. The scrambler istream gets compressed data as input. It's hooked in the chain of istream as the following...
>
> In your previous mail you mentioned you're using v2.1.17. Have you tried with v2.2.10? I think this is already fixed (at least I've successfully used zlib + mail encryption plugin).
>

I just tried version 2.2.11, but the problem seems still to exists.

As soon as the zlib is activated, the scrambler receives 0x1f, 0x8b, 
0x08, ... which is exactly the gz header. The mail doesn't seem to get 
decompressed before it's passed to the scrambler. I assume that the 
order of istreams is messed up.

I've checked already the istreams of the mail_filter and zlib plugins, 
but can't find any differences to my implementation. Do you know any 
other example code, where I can see how ostreams/istreams are chained in 
the correct order?

Best regards,
Philipp

-------------- next part --------------
A non-text attachment was scrubbed...
Name: smime.p7s
Type: application/pkcs7-signature
Size: 4261 bytes
Desc: S/MIME Cryptographic Signature
URL: <http://dovecot.org/pipermail/dovecot/attachments/20140212/28bdd59b/attachment.p7s>