native: add Oracle.finish reentrancy test

internal/contracts/oracle_contract/oracle.go

@@ -1,8 +1,11 @@
 package oraclecontract
 
 import (
+	"github.com/nspcc-dev/neo-go/pkg/interop"
+	"github.com/nspcc-dev/neo-go/pkg/interop/contract"
 	"github.com/nspcc-dev/neo-go/pkg/interop/native/oracle"
 	"github.com/nspcc-dev/neo-go/pkg/interop/native/std"
+	"github.com/nspcc-dev/neo-go/pkg/interop/runtime"
 	"github.com/nspcc-dev/neo-go/pkg/interop/storage"
 	"github.com/nspcc-dev/neo-go/pkg/interop/util"
 )
@@ -22,3 +25,18 @@ func Handle(url string, data interface{}, code int, res []byte) {
 	params := []interface{}{url, data, code, res}
 	storage.Put(storage.GetContext(), "lastOracleResponse", std.Serialize(params))
 }
+
+// HandleRecursive invokes oracle.finish again to test Oracle reentrance.
+func HandleRecursive(url string, data interface{}, code int, res []byte) {
+	// Regular safety check.
+	callingHash := runtime.GetCallingScriptHash()
+	if !callingHash.Equals(oracle.Hash) {
+		panic("not called from oracle contract")
+	}
+
+	runtime.Notify("Invocation")
+	if runtime.GetInvocationCounter() == 1 {
+		// We provide no wrapper for finish in interops, it's not usually needed.
+		contract.Call(interop.Hash160(oracle.Hash), "finish", contract.All)
+	}
+}

internal/contracts/oracle_contract/oracle.manifest.json

@@ -1 +1 @@
-{"name":"Oracle test","abi":{"methods":[{"name":"handle","offset":14,"parameters":[{"name":"url","type":"String"},{"name":"data","type":"Any"},{"name":"code","type":"Integer"},{"name":"res","type":"ByteArray"}],"returntype":"Void","safe":false},{"name":"requestURL","offset":0,"parameters":[{"name":"url","type":"String"},{"name":"filter","type":"ByteArray"},{"name":"callback","type":"String"},{"name":"userData","type":"Any"},{"name":"gasForResponse","type":"Integer"}],"returntype":"Void","safe":false}],"events":[]},"features":{},"groups":[],"permissions":[{"contract":"*","methods":["request"]}],"supportedstandards":[],"trusts":[],"extra":null}
+{"name":"Oracle test","abi":{"methods":[{"name":"handle","offset":14,"parameters":[{"name":"url","type":"String"},{"name":"data","type":"Any"},{"name":"code","type":"Integer"},{"name":"res","type":"ByteArray"}],"returntype":"Void","safe":false},{"name":"handleRecursive","offset":89,"parameters":[{"name":"url","type":"String"},{"name":"data","type":"Any"},{"name":"code","type":"Integer"},{"name":"res","type":"ByteArray"}],"returntype":"Void","safe":false},{"name":"requestURL","offset":0,"parameters":[{"name":"url","type":"String"},{"name":"filter","type":"ByteArray"},{"name":"callback","type":"String"},{"name":"userData","type":"Any"},{"name":"gasForResponse","type":"Integer"}],"returntype":"Void","safe":false}],"events":[{"name":"Invocation","parameters":null}]},"features":{},"groups":[],"permissions":[{"contract":"*","methods":["request","finish"]}],"supportedstandards":[],"trusts":[],"extra":null}

internal/contracts/oracle_contract/oracle.yml

@@ -2,5 +2,6 @@ name: "Oracle test"
 sourceurl: https://github.com/nspcc-dev/neo-go/
 supportedstandards: []
 events:
+  - name: Invocation
 permissions:
-  - methods: ["request"]
+  - methods: ["request", "finish"]