Allow smart contract verification

[shargon]

Required for neo-project/neo-node#628 (comment)

• Allow CheckWitness during Verification.
• Allow SmartContract Verification.
• Allow static varibles during Verification

[meevee98]

Using the same test used in neo-project/neo-node#628 (comment):

I was able to sign and relay the transaction, but the transfer itself doesn't execute.

This only happened when transferring from smart contracts. I'm not sure what's causing the problem, but Transaction.Verify is returning Insufficient Funds even when the smart contract has the requested funds to transfer.

[shargon]

@meevee98 please take a look again.

I think that it's fixed

[ProDog]

@shargon ，I have tested and it's error, NLtxB5cz8kC3ir1JD4nrY1bq7YawCr7Gba is contract address added by import watchonly, then I transfer GAS from this address.

[shargon]

Could you show me your script and manifest?

I tested it with this code, PUSH1 and verify in offset 0

[ConsoleCommand("deploy-test")]
        private void DeployTest()
        {
            var nef = new NefFile()
            {
                Compiler = "",
                Script = new byte[] { (byte)OpCode.PUSH1 },
                Version = new Version(3, 1, 1, 1),
            };
            nef.ScriptHash = nef.Script.ToScriptHash();
            nef.CheckSum = NefFile.ComputeChecksum(nef);

            ContractManifest cf = new ContractManifest()
            {
                Abi = new ContractAbi()
                {
                    Events = new ContractEventDescriptor[0],
                    Hash = nef.ScriptHash,
                    Methods = new ContractMethodDescriptor[]
                     {
                         new ContractMethodDescriptor()
                         {
                              Name="verify",
                               Offset=0,
                                Parameters=new ContractParameterDefinition[0],
                                 ReturnType= ContractParameterType.Boolean
                         }
                     }
                },
                Extra = null,
                Features = ContractFeatures.Payable,
                SafeMethods = WildcardContainer<string>.Create(),
                Groups = new ContractGroup[0],
                Permissions = new ContractPermission[0],
                SupportedStandards = new string[0],
                Trusts = WildcardContainer<UInt160>.Create()
            };

            File.WriteAllBytes("C:\\temporal\\verify.nef", nef.ToArray());
            File.WriteAllBytes("C:\\temporal\\verify.json", Encoding.UTF8.GetBytes(cf.ToJson().ToString()));

            OnDeployCommand("C:\\temporal\\verify.nef", "C:\\temporal\\verify.json");
        }

[ProDog]

A simplified contract.

script(hex string):

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

manifest:

{"groups":[],"features":{"storage":true,"payable":true},"abi":{
    "hash":"0x71edba4ee6e0b0cca5d4b9bc4343b35a87589fe1",
    "methods":
    [
        {
            "name":"verify",
            "offset":"0",
            "parameters":
            [
            ],
            "returntype":"Boolean"
        },
        {
            "name":"test1",
            "offset":"13",
            "parameters":
            [
            ],
            "returntype":"ByteArray"
        },
        {
            "name":"_initialize",
            "offset":"21",
            "parameters":
            [
            ],
            "returntype":"Void"
        }
    ],
    "events":
    [
    ]
},"permissions":[{"contract":"*","methods":"*"}],"trusts":[],"safemethods":[],"supportedstandards":[],"extra":null}

[shargon]

I think that the problem could be that you use static variables and _initialize it's not called during verify. do you have the source?

[shargon]

Also _initialize offset points to STLOC5 instead of INITSLOT :S

[shargon]

@ProDog plase take a look again, now you should be able to use a static variable during verify, but check this error please #1800 (comment)

[ProDog]

I think that the problem could be that you use static variables and _initialize it's not called during verify. do you have the source?

Yes, I will check it.

My contract:

 [Features(ContractFeatures.HasStorage | ContractFeatures.Payable)]
    public partial class APITest : SmartContract
    {        
        private static byte[] Owner = "NNU67Fvdy3LEQTM374EJ9iMbCRxVExgM8Y".ToScriptHash();
        public static bool Verify()
        {
            return Runtime.CheckWitness(Owner);
        }
     }

[ProDog]

A new error:

System.InvalidOperationException: 'Cannot call this SYSCALL with the flag None.'

[shargon]

The problem was that verify can't call CheckWitness because require AllowStates, I changed to ReadOnly it should work, but @erikzhang we should reverify the transaction before persist? the states can be different.

[ProDog]

New error:

[shargon]

@ProDog it was signed by NNU67Fvdy3LEQTM374EJ9iMbCRxVExgM8Y? we should be able to sign with multiple accounts, but we only have one from ... maybe we can change this to be an array?

[ProDog]

@ProDog it was signed by NNU67Fvdy3LEQTM374EJ9iMbCRxVExgM8Y? we should be able to sign with multiple accounts, but we only have one from ... maybe we can change this to be an array?

Yes, so signers doesn't contains it.

[shargon]

Could you try with neo-project/neo-node@c186c36 or with invoke that allow multiple signers?

[shargon]

@ProDog could you do the last test?

[ProDog]

So as neo-project/neo-node#628 (comment), we don't need this judgment.

[shargon]

Done

[ProDog]

Another usage scenario, we use invoke to transfer asset from a verify contract, and contract is sender, like:

invoke nep5Hash transfer [{"type":"Hash160","value":contractHash},{"type":"Hash160","value":toAddress},{"type":"Integer","value":"10"}] contractHash verifyficationAccount

So it shouldn't be WitnessScope.FeeOnly:

neo/src/neo/Wallets/Wallet.cs

Line 212 in 47e8b52

Scopes = WitnessScope.FeeOnly

Now the CLI can't specified the sender to invoke command, I think we can add.

[ProDog]

Tested OK.