package vm import ( "encoding/binary" "github.com/nspcc-dev/neo-go/pkg/encoding/bigint" "github.com/nspcc-dev/neo-go/pkg/vm/emit" "github.com/nspcc-dev/neo-go/pkg/vm/opcode" "github.com/nspcc-dev/neo-go/pkg/vm/stackitem" ) var ( verifyInteropID = emit.InteropNameToID([]byte("Neo.Crypto.VerifyWithECDsaSecp256r1")) multisigInteropID = emit.InteropNameToID([]byte("Neo.Crypto.CheckMultisigWithECDsaSecp256r1")) ) func getNumOfThingsFromInstr(instr opcode.Opcode, param []byte) (int, bool) { var nthings int switch { case opcode.PUSH1 <= instr && instr <= opcode.PUSH16: nthings = int(instr-opcode.PUSH1) + 1 case instr <= opcode.PUSHINT256: n := bigint.FromBytes(param) if !n.IsInt64() || n.Int64() > stackitem.MaxArraySize { return 0, false } nthings = int(n.Int64()) default: return 0, false } if nthings < 1 || nthings > stackitem.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 number of signatures and list of public keys // from the verification script of the contract. func ParseMultiSigContract(script []byte) (int, [][]byte, bool) { var nsigs, nkeys int ctx := NewContext(script) instr, param, err := ctx.Next() if err != nil { return nsigs, nil, false } nsigs, ok := getNumOfThingsFromInstr(instr, param) if !ok { return nsigs, nil, false } var pubs [][]byte for { instr, param, err = ctx.Next() if err != nil { return nsigs, nil, false } if instr != opcode.PUSHDATA1 { break } if len(param) < 33 { return nsigs, nil, false } pubs = append(pubs, param) nkeys++ if nkeys > stackitem.MaxArraySize { return nsigs, nil, false } } if nkeys < nsigs { return nsigs, nil, false } nkeys2, ok := getNumOfThingsFromInstr(instr, param) if !ok { return nsigs, nil, false } if nkeys2 != nkeys { return nsigs, nil, false } instr, _, err = ctx.Next() if err != nil || instr != opcode.PUSHNULL { return nsigs, nil, false } instr, param, err = ctx.Next() if err != nil || instr != opcode.SYSCALL || binary.LittleEndian.Uint32(param) != multisigInteropID { return nsigs, nil, false } instr, _, err = ctx.Next() if err != nil || instr != opcode.RET || ctx.ip != len(script) { return nsigs, nil, false } return nsigs, 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) }