Re: [Tinycc-devel] Can tcc compile itself with Apple M1?

[Niklas Rosencrantz]

Great I think it worked.
It looks like I could compile tcc with itself using the --cpu=x86_64 as described.
What I want to try for research and academic purpose (about compiler security) on my local machine is to experimentally sneak in a RoTT (The Thompson Compiler Hack from https://www.cs.cmu.edu/~rdriley/487/papers/Thompson_1984_ReflectionsonTrustingTrust.pdf).

I want to compare two binaries where one is from a tampered tcc that I changed myself to include the Thompson Compiler Trojan to prove that a certain procedure can mitigate it (the diverse dual-compiling). Then use that evil tcc to compile the next version of tcc to include the invisible Thompson Trojan and then prove that a diverse dual-compilation is a working countermeasure. 

But I'm not sure where exactly to inject the code as described in figure 3.2 and figure 3.3 in the article.
I believe it's somewhere in the struct TCCState but I'm still looking after how to replicate and then mitigate a compiler trojan.

Sincerely,

Niklas



On Sat, Sep 11, 2021 at 6:53 AM Christian Jullien <eligis@orange.fr> wrote:
>
> Hi,
>
>  
>
> On macOS, tcc has several limitations and it supports only x86_64 backend.
>
> On M1, it works thanks to Rostetta translation.
>
> You can compile tcc with a boostrapped tcc if you use –cpu=x86_64 ./configure flag
>
>  
>
> I don’t think we are too far from a native arm64 backend as we have already all the stuff for it but nobody is working on it AFAIK.
>
> I’m ready to help volunteers but I have no enough knowledge on the binary forma to do it myself.
>
>  
>
> From: Tinycc-devel [mailto:tinycc-devel-bounces+eligis=orange.fr@nongnu.org] On Behalf Of Niklas Rosencrantz
> Sent: Saturday, September 11, 2021 03:54
> To: tinycc-devel@nongnu.org
> Subject: [Tinycc-devel] Can tcc compile itself with Apple M1?
>
>  
>
> Hello,
> It worked to compile and run tcc with Apple M1 but I could not make it compile itself.
>
> I get the following error message
>
> error: 'tcc' failed to compile conftest.c.
>
>  % ./tcc conftest.c
>
> tcc: error: R_AARCH64_(JUMP|CALL)26 relocation failed (val=100001176, addr=1000010cc)
>
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