576161 - A ServiceCaller service can make remoting service calls much easier

Status: RESOLVED WONTFIX

(Core :: DOM: Content Processes, enhancement, P5)

Description

[Alon Zakai (:azakai)]

Attachment: Patch for discussion purposes

We need to remote calls for various services (e.g. cookie service, permissions manager, etc. etc.). Instead of writing a new IPDL protocol for each, which involves several new files, changes to several others, and various opportunities for introducing bugs, we can do all of these using a single path, as follows.

1. Content process sends an IPC message, saying what service, what method, and what parameters.
2. Message is received, and a ServiceCaller JS service is called, which then calls the appropriate service for us. ("we heard you like service calls, so we put a service call in your service call")

This would be able to work for any service/interface which is scriptable, whose relevant method is synchronous, and whose parameters/return value are remotable. Remoting such calls would become a matter of a few lines of non-bug-prone code.

Attached is a patch for discussion purposes. It works but is not fully polished. It includes the necessary code to remote the permissions manager.

Comment 1

[Mark Finkle (:mfinkle) (use needinfo?)]

Comment on attachment 455327 [details] [diff] [review]
Patch for discussion purposes

Drive by

Nice concept. Makes it almost as easy as using JS and MessageManager

>+EXTRA_PP_COMPONENTS = \
>+  serviceCaller.js \

convention is "nsServiceCaller.js"

>diff --git a/dom/ipc/nsIServiceCaller.idl b/dom/ipc/nsIServiceCaller.idl
>+[scriptable, uuid(1a414df4-7d24-496c-86f3-1f5f02a2a275)]
>+interface nsIServiceCaller: nsISupports
>+{
>+  /**
>+   */
>+  PRInt32 callInt(in ACString aContractId, in ACString aService,
>+                  in ACString aMethod, in AString aArguments);
>+};

* Passing the arguments as a string seems awkward. Maybe just use an array?
* nsIServiceCaller is a bit too vague. Doesn't tell me that this is for remoting.

Anyway, like I said - nice idea!

Comment 2

[Alon Zakai (:azakai)]

I talked briefly with bsmedberg on irc about this. He said he was concerned about letting arbitrary services and methods be called, since the content process might be compromised.

I believe this can be addressed with a whitelist, and that overall it would be a net gain for security, as we would be writing less protocol code.

Need to discuss this further.

Comment 3

[Firefox Bug Husbandry Bot]

https://bugzilla.mozilla.org/show_bug.cgi?id=1472046

Move all DOM bugs that haven’t been updated in more than 3 years and has no one currently assigned to P5.

If you have questions, please contact :mdaly.

Comment 4

[Jens Stutte [:jstutte]]

It seems that nobody missed this enough to ever do it. Should we just close this?

Comment 5

[Olli Pettay [:smaug][[e-mail]]]

And we shouldn't have done this anyhow.