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w3cping / privacy-request

tracking privacy reviews of W3C specifications
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WebAssembly 2024-10-07 > 2024-10-31 #143

Open dschuff opened 1 month ago

dschuff commented 1 month ago

In the issue title above add the document name followed by the date of this request, then the date of your proposed deadline for comments.

This is a request for transition for version 2.0 of all 3 WebAssembly specifications, namely the core spec, which defines the core code format and semantics; the JS API specification, which provides a JavaScript API for interacting with WebAssembly; and the Web API specification, which describes the integration of WebAssembly with the broader web platform.

For review convenience, here is a list of the explainers for the proposals that have gone into 2.0, compared to 1.0 (currently in REC state). These are informal descriptions of the proposed changes and are not canonical, but describe an overview of the feature and could be useful in determining whether there is anything of interest for horizontal reviewers.

Note also that the specifications contain change history sections summarizing additions to each spec (core, JS, Web) listing and summarizing additions since version 1.0. The table summarizes the effect on the JS spec. The Web spec is unchanged since 1.0

Explainer Specs affected
Nontrapping float-int conversion Core
Sign-extension operators Core
Multi-value block and function returns Core, JS
JS BigInt Integration JS
Reference Types Core, JS
Bulk Memory and table instructions Core
SIMD Vector instructions Core
NalaGinrut commented 1 month ago

hi folks! Thanks for all the efforts! I'm the IE of PING. And I'll spend some time to take a look at it.

NalaGinrut commented 4 weeks ago

Here are the brief result of the review. This review is only for the new released part, if I think there's any part should be reconsider, I will raise other issue. The privacy review result will be showed with ⭕ or ❌ or ❓. For the ❓ case, please answer my question. Thanks!

WASM Web API

Registration for the application/wasm media type. ⭕

Result: fine.

WASM JS API

Multiple Values ⭕

Result: It's an abstract concept within the VM implementation layer, simply wrapping function returned multiple values into an array. This process is generally transparent to web users, so from this perspective, I don’t see a privacy concern.

BigInt Integration ⭕

Result: support bigint, no privacy concern.

Reference types ❓

Question: If I wrap a privacy info into a closure, and export it from a module to other module, considering WASM blob is a blackbox, is there effective way to mark this closure, or trace its activity in the Call Hierarchy?

WASM Core API

Reference types ❓

Same question as above.

Others ⭕

Thanks!

dschuff commented 3 weeks ago

An externref-typed reference can refer to any JS value and (from the point of view of core wasm) is opaque; there is no way to specially-designate or mark a reference as having a particular property such as containing sensitive information. Having said that, I think the general problem of taint-tracking values as they flow around the program is basically the same in the JS+Wasm system as it is with plain JS. Reference-typed values that flow into (or out of) Wasm are passed via an import or export; for example being passed in as an argument to an exported function, as a return value from an imported function, or written into a table via the argument to the Table.set() API. If you had an existing JS taint-tracking system and you wanted to follow such values into Wasm, you would augment that system to be aware of wasm instructions that handle references (currently there are few, e.g. getters/setters on locals, globals, and tables; select, ref.func). Then you would make it understand the wasm instantiation API so that it could follow values as they travel from JS to wasm and back. Actually the problems seems much more tractable compared to the already-existing problem you'd have with JS alone, since wasm is statically-typed and validated, and has no APIs outside of the interface to JS.