package vm import ( "encoding/binary" "github.com/nspcc-dev/neo-go/pkg/vm/emit" "github.com/nspcc-dev/neo-go/pkg/vm/opcode" ) var ( verifyInteropID = emit.InteropNameToID([]byte("Neo.Crypto.ECDsaVerify")) multisigInteropID = emit.InteropNameToID([]byte("Neo.Crypto.ECDsaCheckMultiSig")) ) func getNumOfThingsFromInstr(instr opcode.Opcode, param []byte) (int, bool) { var nthings int switch instr { case opcode.PUSH1, opcode.PUSH2, opcode.PUSH3, opcode.PUSH4, opcode.PUSH5, opcode.PUSH6, opcode.PUSH7, opcode.PUSH8, opcode.PUSH9, opcode.PUSH10, opcode.PUSH11, opcode.PUSH12, opcode.PUSH13, opcode.PUSH14, opcode.PUSH15, opcode.PUSH16: nthings = int(instr-opcode.PUSH1) + 1 case opcode.PUSHBYTES1: nthings = int(param[0]) case opcode.PUSHBYTES2: nthings = int(binary.LittleEndian.Uint16(param)) default: return 0, false } if nthings < 1 || nthings > MaxArraySize { return 0, false } return nthings, true } // IsMultiSigContract checks whether the passed script is a multi-signature // contract. func IsMultiSigContract(script []byte) bool { _, ok := ParseMultiSigContract(script) return ok } // ParseMultiSigContract returns list of public keys from the verification // script of the contract. func ParseMultiSigContract(script []byte) ([][]byte, bool) { var nsigs, nkeys int ctx := NewContext(script) instr, param, err := ctx.Next() if err != nil { return nil, false } nsigs, ok := getNumOfThingsFromInstr(instr, param) if !ok { return nil, false } var pubs [][]byte for { instr, param, err = ctx.Next() if err != nil { return nil, false } if instr != opcode.PUSHDATA1 { break } if len(param) < 33 { return nil, false } pubs = append(pubs, param) nkeys++ if nkeys > MaxArraySize { return nil, false } } if nkeys < nsigs { return nil, false } nkeys2, ok := getNumOfThingsFromInstr(instr, param) if !ok { return nil, false } if nkeys2 != nkeys { return nil, false } instr, _, err = ctx.Next() if err != nil || instr != opcode.PUSHNULL { return nil, false } instr, param, err = ctx.Next() if err != nil || instr != opcode.SYSCALL || binary.LittleEndian.Uint32(param) != multisigInteropID { return nil, false } instr, _, err = ctx.Next() if err != nil || instr != opcode.RET || ctx.ip != len(script) { return nil, false } return pubs, true } // IsSignatureContract checks whether the passed script is a signature check // contract. func IsSignatureContract(script []byte) bool { if len(script) != 41 { return false } ctx := NewContext(script) instr, param, err := ctx.Next() if err != nil || instr != opcode.PUSHDATA1 || len(param) != 33 { return false } instr, _, err = ctx.Next() if err != nil || instr != opcode.PUSHNULL { return false } instr, param, err = ctx.Next() if err != nil || instr != opcode.SYSCALL || binary.LittleEndian.Uint32(param) != verifyInteropID { return false } return true } // IsStandardContract checks whether the passed script is a signature or // multi-signature contract. func IsStandardContract(script []byte) bool { return IsSignatureContract(script) || IsMultiSigContract(script) }