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John the Ripper jumbo - advanced offline password cracker, which supports hundreds of hash and cipher types, and runs on many operating systems, CPUs, GPUs, and even some FPGAs
https://www.openwall.com/john/
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Reconsider --enable-opencl / --disable-opencl #5397

Open solardiz opened 11 months ago

solardiz commented 11 months ago

We no longer depend on OpenCL library nor headers being available on the system at build time (we load the library dynamically at runtime, and we use our own copy of the headers), but we still check for both in configure and don't enable OpenCL support if either or both are missing.

Do we want to continue checking (I think @claudioandre-br said so)? If so, or regardless, do we possibly want explicit --enable-opencl to override any checks (just like --disable-opencl would)? I've just tested, and it does not yet do that, and indeed we currently only document --disable-opencl. We'll also need to document --enable-opencl if we start supporting it.

As to the default, if we do continue checking, then maybe check only for the library? We definitely don't need the headers anymore, at all, but the library we'd use at runtime, so it makes more sense to check for it. Alternatively, we could make the check an OR - enable OpenCL support by default if at least one of the two - library or headers - is found at build time, indicating that the system is possibly meant to work with OpenCL and is maybe just slightly misconfigured.

solardiz commented 11 months ago

if we do continue checking, then maybe check only for the library? We definitely don't need the headers anymore

We no longer check the headers due to @claudioandre-br's #5398.

We still check the library. We still do not have --enable-opencl that could be used to build with OpenCL on library-less systems - I think we should at least add that.

solardiz commented 10 months ago

@claudioandre-br I really would like to have --enable-opencl at least for build-testing of changes to OpenCL host code on systems without OpenCL.

solardiz commented 10 months ago

I really would like to have --enable-opencl at least for build-testing of changes to OpenCL host code on systems without OpenCL.

Also for --fuzz of OpenCL formats' hash parsing, including on CI, without needing to install an OpenCL library in there. Edit: this use case probably needs more changes, as we currently initialize an OpenCL device even during --fuzz of such formats.

solardiz commented 3 months ago

@claudioandre-br Do you want to implement --enable-opencl, please? Looks like besides the reasons in my previous comments here, it'd also let us simplify the documentation. There would be no need to provide an OpenCL library path at build time. Such path, if provided, does not currently help john find the library at runtime anyway.