File attachments not taken into consideration for file size limit?

[niftylettuce]

This might be a core bug, as I wrote a basic test and a file created that's over the limit sent just fine.

It didn't throw an error, and it seems like we're not adding to the this.dataBytes for attachments.

this._dataStream.sizeExceeded = this.dataBytes > this._maxBytes;

[andris9]

It’s a soft fail, you get an indicator that the file size was too big but nothing is rejected automatically

[niftylettuce]

It doesn't fail though at all, also stream if (stream.sizeExceeded) { is always false.

[niftylettuce]

In other words I don't get any indicators, no error messages, nothing

[niftylettuce]

Also, I tried it without even using attachments, it still doesn't seem to work. The byte reading seems to be inaccurate... hmm

[andris9]

Could you try with this example script to see if it fails if message is larger than 25 bytes:

/* eslint-env es6 */

'use strict';

const SMTPServer = require('smtp-server').SMTPServer;

let server = new SMTPServer({
    logger: true,
    disabledCommands: ['STARTTLS', 'AUTH'],
    size: 25
});

server.onData = function(stream, session, callback) {
    let chunks = [];
    let chunklen = 0;

    stream.on('data', chunk => {
        chunks.push(chunk);
        chunklen += chunk.length;
    });

    stream.on('end', () => {
        let err;

        if (stream.sizeExceeded) {
            err = new Error('Maximum allowed message size 25B exceeded');
            err.responseCode = 552;
            return callback(err);
        }

        process.stdout.write(Buffer.concat(chunks, chunklen));

        callback();
    });
};

server.listen(5525);

[niftylettuce]

That's not a really complete example script :(

On Sun, Oct 1, 2017 at 4:41 AM, Andris Reinman notifications@github.com wrote:

Could you try with this example script to see if it fails if message is larger than 25 bytes:

/ eslint-env es6 / 'use strict'; const SMTPServer = require('smtp-server').SMTPServer; let server = new SMTPServer({ logger: true, disabledCommands: ['STARTTLS', 'AUTH'], size: 25 }); server.onData = function(stream, session, callback) { let chunks = []; let chunklen = 0;

stream.on('data', chunk => {
    chunks.push(chunk);
    chunklen += chunk.length;
});

stream.on('end', () => {
    let err;

    if (stream.sizeExceeded) {
        err = new Error('Maximum allowed message size 1kB exceeded');
        err.statusCode = 552;
        return callback(err);
    }

    process.stdout.write(Buffer.concat(chunks, chunklen));

    callback();
});

}; server.listen(5525);

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-- @niftylettuce

[andris9]

and btw you can only check the byte size after the stream has been processed. This value is not known beforehand as the client has not yet sent the message.

[andris9]

run the script and try to send mail to port 5525. if the message is bigger than 25 bytes, the message should fail

[andris9]

$ telnet localhost 5525
Trying ::1...
Connected to localhost.
Escape character is '^]'.
220 Macintosh.lan ESMTP
ehlo foo
250-Macintosh.lan Nice to meet you, [::1]
250-PIPELINING
250-8BITMIME
250-SMTPUTF8
250 SIZE 25
mail from:<test@example>
250 Accepted
rcpt to:<test@example>
250 Accepted
data
354 End data with <CR><LF>.<CR><LF>
subject: test

tere
tere
tere, vana kere
kuidas laheb
voi mid aiganes
.
552 Maximum allowed message size 25B exceeded

[andris9]

Here's a longer version, first message is passed (shorter than 25 bytes), second one fails:

$ telnet localhost 5525
Trying ::1...
Connected to localhost.
Escape character is '^]'.
220 Macintosh.lan ESMTP
ehlo foo
250-Macintosh.lan Nice to meet you, [::1]
250-PIPELINING
250-8BITMIME
250-SMTPUTF8
250 SIZE 25
mail from:<test@example>
250 Accepted
rcpt to:<test@example>
250 Accepted
data
354 End data with <CR><LF>.<CR><LF>
subject: short

hello
.
250 OK: message queued
mail from:<test@example.com>
250 Accepted
rcpt to:<test@example.com>
250 Accepted
data
354 End data with <CR><LF>.<CR><LF>
subject: longer message

this is going to fail
.
552 Maximum allowed message size 25B exceeded

[andris9]

So, stream.sizeExceeded is a soft indicator that you can check only after the message is processed and not immediately in the start of the onData handler (client has not yet sent anything at that point so there's nothing to check).

[niftylettuce]

will try to fix my code, I think I was missing something

[niftylettuce]

@andris9 I just tested it again with attachments and it does not work.

[niftylettuce]

Output:

databytes 35873301
this._maxBytes 26214400

The stream never emits an end or close event when piping along it seems, and that's the culprit I believe.

[niftylettuce]

I think I've figured it out, give me a bit and I'll document what I did.

[andris9]

Can you create a minimal test case that I could try out. I don’t see how the attachments could affect anything as smtp-server treats the entire email as a blackbox binary data stream

[niftylettuce]

It's totally working fine, I just had some stuff backwards :)

On Sun, Oct 1, 2017 at 12:40 PM, Andris Reinman notifications@github.com wrote:

Can you create a minimal test case that I could try out. I don’t see how the attachments could affect anything as smtp-server treats the entire email as a blackbox binary data stream

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-- @niftylettuce