[Dovecot] Order of istream and ostream chains
Hi,
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...
static int scrambler_istream_opened(struct mail *_mail, struct istream **stream) { struct mail_private *mail = (struct mail_private *)_mail; union mail_module_context *mmail = SCRAMBLER_MAIL_CONTEXT(mail); struct istream *input, *inputs[2];
input = *stream;
*stream = scrambler_istream_create(input);
i_stream_unref(&input);
return mmail->super.istream_opened(_mail, stream);}
static void scrambler_mail_allocated(struct mail *_mail) { struct mail_private *mail = (struct mail_private *)_mail; struct mail_vfuncs *v = mail->vlast; union mail_module_context *mmail;
mmail = p_new(mail->pool, union mail_module_context, 1);
mmail->super = *v;
mail->vlast = &mmail->super;
v->istream_opened = scrambler_istream_opened;
MODULE_CONTEXT_SET_SELF(mail, scrambler_mail_module, mmail);}
How can I reverse the order of istreams? Should I use another hook or vfuns?
I'm stuck in the problem for a while now, so any help would be very welcome.
Best regards, Philipp
On 12.2.2014, at 2.27, Philipp Brüll philippbruell@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).
On 11/02/14 21:32, Timo Sirainen wrote:
On 12.2.2014, at 2.27, Philipp Brüll philippbruell@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).
Thanks for the fast reply. Yes, I'm using v2.1.17. If this is a bug in 2.1, is there a workaround existing?
I'm already pushing the admin to upgrade to 2.2, but I don't know is this is happening soon ;-)
Kind regards, Philipp
On 11/02/14 21:32, Timo Sirainen wrote:
On 12.2.2014, at 2.27, Philipp Brüll philippbruell@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
participants (2)
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Philipp Brüll
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Timo Sirainen