all: remove kilic dependency from bls12381 fuzzers

[jwasinger]

The kilic bls12381 implementation has been archived. It shouldn't be necessary to include it as a fuzzing target any longer.

This also adds fuzzers for G1/G2 mul that use inputs that are guaranteed to be valid. Previously, we just did random input fuzzing for these precompiles.

[MariusVanDerWijden]

Looks like this fails currently:

func TestCrossG1MultiExp(t *testing.T) {
	input := []byte("0")
	fuzzCrossG1MultiExp(input)
}

[kevaundray]

This looks good to me!

[jwasinger]

Ah there's one thing: We only fuzz the MSM precompiles using random inputs. I'm going to add two additional fuzzers that fuzz these with inputs that are known to be valid.

[kevaundray]

Ah there's one thing: We only fuzz the MSM precompiles using random inputs. I'm going to add two additional fuzzers that fuzz these with inputs that are known to be valid.

I think it would be good to add the identity/zero point as input to one of these, along with other known valid points

[jwasinger]

Yeah definitely. Actually, I need to give the added fuzzers a longer run and prob adjust the seed corpus to increase the coverage.

[holiman]

Sorry, this seems to have been forgotten a bit, and bitrotted. Could you please rebase this?

[jwasinger]

Oh, this is missing a cross fuzzer for g2 multiexp.

[MariusVanDerWijden]

LGTM

[MariusVanDerWijden]

This might not work, since FuzzCrossG2Mul is a prefix of FuzzCrossG2MultiExp
Go complains on my machine about it:

go test --fuzz FuzzCrossG1Mul
testing: will not fuzz, -fuzz matches more than one fuzz test: [FuzzCrossG1MultiExp FuzzCrossG1Mul]
FAIL
exit status 1

The way I found to fix it, was to specify FuzzCrossG1Mul. with a trailing dot.
I don't how if the compile_fuzzer script will work with this, but I think we should give it a try like it is right now and fix it up if necessary

[holiman]

I think FuzzCrossG1Mul$ is another to way to make it work. However, we can try it as is. The compilescript passes it to gofuzz-shim. Seems to me that it's parsed literally, not regexpy: https://github.com/holiman/gofuzz-shim/blob/main/main.go#L95