An issue about parsing URL with regular expression

[Jinyn01]

Description:

When I parse URLs with a complex regular expression, the result of XS is Killed, which looks like an issue.

Environment：

Ubuntu 18.04 x86_64

JS Information:

Moddable SDK 3.7.0

Testcase:

const regex = /^(?:(?![^:@]+:[^:@\/]*@)([^:\/?#.]+):)?(?:\/\/\/?)?((?:(([^:@]*):?([^:@]*))?@)?([^:\/?#]*)(?::(\d*))?)(((\/(?:[^?#](?![^?#\/]*\.[^?#\/.]+(?:[?#]|$)))*\/?)?([^?#\/]*))(?:\?([^#]*))?(?:#(.*))?)/
const str = 'https://www.example.com/path/to/resource?param1=value1&param2=value2#section';

const result = regex.exec(regex);

Result:

Killed

[phoddie]

Thank you for the report. The problem reproduces here on macOS as well. It looks like the process is killed because it eventually allocates too much memory.

Note that the title of this issue is incorrect. The test case does not parse a URL. The URL is in the variable str but that is unused when calling exec. Is this a test case from a fuzzing run?

Note also that this issue is reported against Moddable SDK 3.7.0. The current release is 4.2.1.

FWIW - JavaScriptCore and V8 evaluate the regex quickly and without an error.

We will investigate.

[Jinyn01]

Thank you very much for your reply. I'm sorry for my carelessness, I made a mistake while locating the problem. Actually, this piece of code was originally designed for URL parsing, but I mistakenly wrote the function parameter str as regex. The correct code should be const result = regex.exec(str). I apologize for any inconvenience caused.

[phoddie]

Thank you for the clarification. The problem happens using either str or regex as the argument. We are testing a fix now. That should be available later in the week.

[phoddie]

The fix for this is live now. Please give it a try.

[phoddie]

Just FWIW -- the Moddable SDK includes an implementation of the web's URL class. That might be a little more straightforward than a regular expression. But, do whatever works best for you.

[Jinyn01]

I have tried the solution you provided and the problem has been successfully resolved. Thank you very much.

[phoddie]

Excellent. Thanks again for reporting the issue. We're always glad to fix issues like this.