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0 pointsgameoverhumans2y ago0 comments

Rather than just downvote you for stating incorrect things with such conviction, I'll refer you to Apple's own website :)

https://support.apple.com/en-eg/guide/security/sec15bfe098e/...

> Memory pages marked as both writable and executable can be used only by apps under tightly controlled conditions: The kernel checks for the presence of the Apple-only dynamic code-signing entitlement. Even then, only a single mmap call can be made to request an executable and writable page, which is given a randomized address. Safari uses this functionality for its JavaScript Just-in-Time (JIT) compiler.

In other words, Apple only allows Apple to do Javascript JIT on iOS.

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3 comments · 1 top-level

btown2y ago· 2 in thread

While this is technically true, WKWebView (which I believe is used by all non-Apple browsers on iOS) does allow Javascript JIT, because the renderer runs in a subprocess with these permissions. See: https://news.ycombinator.com/item?id=19379739 .

But there are many other reasons besides JIT to want to have non-Apple-Webkit-based rendering engines (including wanting different JS engines with their own JIT) - and so IMO it's very much a restriction that regulators should force Apple to relax. The security considerations should be no different than those on a desktop platform.

gameoverhumansOP2y ago

Interesting, thanks. Didn't realise there was ways to embed WebKit views that also got JIT (escaped the walled garden a while ago!)

Still, my original point still stands. As you note, you can't have Spidermonkey running on iOS doing JIT. But you also couldn't have Gecko doing rendering and using WebKit JIT, either. ... Right?

> The security considerations should be no different than those on a desktop platform.

Completely agree. The "it's for your own security" angle is just usual Apple FUD to make their anti-competitive stance seem pro-consumer.

saagarjha2y ago

Your control over the web process is very limited, correct.

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