Free memory before running psfree

[mrdude2478]

In PSFree we can clear some browser memory in async function main() before starting to exploit.

First create a function to clear some memory:

async function forceGC() {
    try {
        for (let i = 0; i < 10; i++) {
            let junk = new Array(10000).fill(0);
            junk = null;
            await new Promise(resolve => setTimeout(resolve, 10)); // Give browser time to GC
        }
    }
    catch (err) {
        log("Failed to free memory");
    }
}

In the first line of async function main(), we call the function:

await forceGC();

This clears some browser memory before the exploit starts so we get less chance of out of memory error.

I tried by creating an html file to load a large jpeg before starting the exploit, this would cause a memory error when trying to run psfree, with the added function, this reduced this error quite a bit and so I thought I'd pass on the information if you want to test it.
You can increase the amount you clear by altering this line - (let i = 0; i < 10; i++), increase10 to 20/30 etc...

I have mine set to 50 and that works quite well for me.

[viggen66]

Another suggestion as the above which is great, increase heap grooming allocation from 0x200 to 0x400.

const num_grooms = 0x400;

Higher grooming allocation normally results in better exploit success, as it makes heap layout more deterministic

[Tamyhen]

Great suggestions. Maybe try creating a pull request