This is not correct, it is not necessary to specify a maximum memory size. See the WebAssembly specification https://webassembly.github.io/spec/core/syntax/modules.html#.... Due to 32-bit address space, the maximum…
Very cool, thanks a lot for the example!
My reading of the article is not that it promotes "anti-intellectualism" or that it argues to remove all implicit precedence or associativity rules. I think it actually gives a nuanced answer to your question "where do…
See e.g. https://www.digwebinterface.com/?hostnames=facebook.com&ns=a... for responses from different nameservers.
Thanks a lot for the additional background, and also for all the work on WebAssembly. It is a very cool language and having it available with linear memory now is much better than if it were still in the works due to…
Good summary and clarification. Yes, we do not aim to break out of the (browser) sandbox, and yes the example exploits only use functions that are already imported into the vulnerable WebAssembly module. However, I…
Daniel here, one of the authors. You are right, some of the issues highlighted in the paper could be solved by compilers targeting WebAssembly. One such mitigation that is (currently) missing are stack canaries. In…
Daniel [1], one of the authors here. Feel free to ask also technical questions, I'll try my best to answer them. If you don't feel like reading the whole paper, there is also a short (~10 min) video on the conference…
> This doesn't really seem to offer anything useful, or even contain new information. You are right in that we do not try to attack a concrete host implementation or aim to break out of the sandbox. I disagree, however,…
Excellent explanations. > C++ compiled to WebAssembly generally manages its own parallel "shadow stack" in linear memory In the paper, we call the compiler-organized stack in linear memory the "unmanaged stack", to…
> Do some of the safety measures you consider translate well in this model? Yes, I think several mitigations could be deployed without requiring a change to the language, only by changing compilers and runtime…
> some C library you have compiled to WASM: wrap that functionality up with an interface, compile that to WASM, and only pass it the image data you're happy for it to see That is good advice. Separately compiling C code…
I am not sure I understand the sentence "limiting the WA spec to only try to sandbox the WA binary from outside memory". I would not say that we (as in: the authors of the paper) are trying to limit the spec, or that we…
Hi everyone, Daniel here (one of the authors, I am the PhD student in the video). Great to see the paper submitted and discussed :-) Sorry for being a bit late to the discussion, I will try to answer the questions in…
Thanks for the warm words, happy to hear that others are interested in this project and WebAssembly in general! Regarding your question: No, I have not yet contacted the WebAssembly people at Mozilla. But it's…
Daniel here, PhD student working on this. Ask away if you have any questions :) For now, this is in an early stage, so probably mostly interesting to researchers or as inspiration. But I am working on making it more…
This is not correct, it is not necessary to specify a maximum memory size. See the WebAssembly specification https://webassembly.github.io/spec/core/syntax/modules.html#.... Due to 32-bit address space, the maximum…
Very cool, thanks a lot for the example!
My reading of the article is not that it promotes "anti-intellectualism" or that it argues to remove all implicit precedence or associativity rules. I think it actually gives a nuanced answer to your question "where do…
See e.g. https://www.digwebinterface.com/?hostnames=facebook.com&ns=a... for responses from different nameservers.
Thanks a lot for the additional background, and also for all the work on WebAssembly. It is a very cool language and having it available with linear memory now is much better than if it were still in the works due to…
Good summary and clarification. Yes, we do not aim to break out of the (browser) sandbox, and yes the example exploits only use functions that are already imported into the vulnerable WebAssembly module. However, I…
Daniel here, one of the authors. You are right, some of the issues highlighted in the paper could be solved by compilers targeting WebAssembly. One such mitigation that is (currently) missing are stack canaries. In…
Daniel [1], one of the authors here. Feel free to ask also technical questions, I'll try my best to answer them. If you don't feel like reading the whole paper, there is also a short (~10 min) video on the conference…
> This doesn't really seem to offer anything useful, or even contain new information. You are right in that we do not try to attack a concrete host implementation or aim to break out of the sandbox. I disagree, however,…
Excellent explanations. > C++ compiled to WebAssembly generally manages its own parallel "shadow stack" in linear memory In the paper, we call the compiler-organized stack in linear memory the "unmanaged stack", to…
> Do some of the safety measures you consider translate well in this model? Yes, I think several mitigations could be deployed without requiring a change to the language, only by changing compilers and runtime…
> some C library you have compiled to WASM: wrap that functionality up with an interface, compile that to WASM, and only pass it the image data you're happy for it to see That is good advice. Separately compiling C code…
I am not sure I understand the sentence "limiting the WA spec to only try to sandbox the WA binary from outside memory". I would not say that we (as in: the authors of the paper) are trying to limit the spec, or that we…
Hi everyone, Daniel here (one of the authors, I am the PhD student in the video). Great to see the paper submitted and discussed :-) Sorry for being a bit late to the discussion, I will try to answer the questions in…
Thanks for the warm words, happy to hear that others are interested in this project and WebAssembly in general! Regarding your question: No, I have not yet contacted the WebAssembly people at Mozilla. But it's…
Daniel here, PhD student working on this. Ask away if you have any questions :) For now, this is in an early stage, so probably mostly interesting to researchers or as inspiration. But I am working on making it more…