StreamParser hangs when processing a Contact line with multiple bindings

[Marian-Kechlibar]

A Contact: header in a response to REGISTER request may contain one or more values separated by commas, like this:

Contact: <sip:e52@78.102.16.243:55497;transport=tls>;expires=111;received="sip:e52@78.102.16.243:55497";reg-id=1;+sip.instance="<d79966b435633699badcf12507380d51d4e97eab>",<sip:e52@78.102.16.243:17127;transport=tls>;expires=258;received="sip:e52@78.102.16.243:17127";reg-id=2;+sip.instance="<65be01c100f2ccd762df61057569f037bd46a367>"

This actually happens in practice if the indicated user is registered from multiple devices.

The StreamParser, as of version 0.7.0., does not anticipate this possibility and will enter an infinite loop in some cases. The main problem seems to be that the method

ContactHeader.parse(array $hbody)

receives only an array of count 1, while it should receive an array of count N, exploded by the delimiter ,.

I made a crude and ugly fix in ContactHeader.parse like this:

    public static function parse(array $hbody): ContactHeader
    {
        $ret = new static;
        $hbody2 = array();
        foreach ($hbody as $hline) {
            $explodedLine = explode(',', $hline);
            $hbody2 = array_merge($hbody2, $explodedLine);
        }
        $hbody = $hbody2;

It works, but it is also very ugly. I suppose that the original author has a better solution.

AFAIK, in case of SIP, if a header contains commas, it is as if the same header was present multiple times, so

Contact: XX,YY

is equivalent to

Contact: XX
Contact: YY

[Marian-Kechlibar]

@cdosoftei Feel free to contact me for more info. Unfortunately whenever I trigger this bug, my entire Apache hangs (I am developing on XAMPP) and it takes a few minutes to get it running again, so the amount of collected examples is very limited.

[cdosoftei]

Hi @Marian-Kechlibar!

Thanks for the detailed feedback; indeed the provided sample should have parsed out just fine. I've addressed the bug in the v0.7.1 branch. Your sample parses out to the following JSONified output:

{
    "uri": {
        "scheme": "sip",
        "user": "e52",
        "host": "78.102.16.243",
        "ipv6": false,
        "port": 55497,
        "transport": "tls",
        "params": [],
        "headers": []
    },
    "expires": 111,
    "params": {
        "received": "\"sip:e52@78.102.16.243:55497\"",
        "reg-id": "1",
        "+sip.instance": "\"<d79966b435633699badcf12507380d51d4e97eab>\""
    }
},
{
    "uri": {
        "scheme": "sip",
        "user": "e52",
        "host": "78.102.16.243",
        "ipv6": false,
        "port": 17127,
        "transport": "tls",
        "params": [],
        "headers": []
    },
    "expires": 258,
    "params": {
        "received": "\"sip:e52@78.102.16.243:17127\"",
        "reg-id": "2",
        "+sip.instance": "\"<65be01c100f2ccd762df61057569f037bd46a367>\""
    }
}

Please let me know how it works for you. Barring any issues, I want to make a few more CI updates before releasing it (switch to GitHub Actions and drop Travis).

[Marian-Kechlibar]

I can confirm that the patched version works for me. I am looking forward for release of 0.7.1 :)