[lbry] txscript: introduce claim script

Co-authored-by: Brannon King <countprimes@gmail.com>
This commit is contained in:
Roy Lee 2018-06-14 19:13:08 -07:00
parent 185cb711b5
commit 6d80d906a8
2 changed files with 296 additions and 0 deletions

216
txscript/claimscript.go Normal file
View file

@ -0,0 +1,216 @@
package txscript
import (
"bytes"
"fmt"
"unicode/utf8"
)
const (
// MaxClaimScriptSize is the max claim script size in bytes, not including the script pubkey part of the script.
MaxClaimScriptSize = 8192
// MaxClaimNameSize is the max claim name size in bytes, for all claim trie transactions.
MaxClaimNameSize = 255
ClaimIDLength = 160 / 8
claimScriptVersion = 0
)
// These constants are used to identify a specific claim script Error.
// The error code starts from 200, which leaves enough room between the rest
// of script error codes (numErrorCodes)
const (
// ErrNotClaimScript is returned when the script does not have a ClaimScript Opcode.
ErrNotClaimScript ErrorCode = iota + 200
// ErrInvalidClaimNameScript is returned a claim name script does not conform to the format.
ErrInvalidClaimNameScript
// ErrInvalidClaimSupportScript is returned a claim support script does not conform to the format.
ErrInvalidClaimSupportScript
// ErrInvalidClaimUpdateScript is returned a claim update script does not conform to the format.
ErrInvalidClaimUpdateScript
)
func claimScriptError(c ErrorCode, desc string) Error {
return Error{ErrorCode: c, Description: desc}
}
// ClaimNameScript creates a claim name script.
func ClaimNameScript(name string, value string) ([]byte, error) {
return NewScriptBuilder().AddOp(OP_CLAIMNAME).AddData([]byte(name)).AddData([]byte(value)).
AddOp(OP_2DROP).AddOp(OP_DROP).AddOp(OP_TRUE).Script()
}
// ClaimSupportScript creates a support claim script.
func ClaimSupportScript(name string, claimID []byte, value []byte) ([]byte, error) {
builder := NewScriptBuilder().AddOp(OP_SUPPORTCLAIM).AddData([]byte(name)).AddData(claimID)
if len(value) > 0 {
return builder.addData(value).AddOp(OP_2DROP).AddOp(OP_2DROP).AddOp(OP_TRUE).Script()
}
return builder.AddOp(OP_2DROP).AddOp(OP_DROP).AddOp(OP_TRUE).Script()
}
// ClaimUpdateScript creates an update claim script.
func ClaimUpdateScript(name string, claimID []byte, value string) ([]byte, error) {
return NewScriptBuilder().AddOp(OP_UPDATECLAIM).AddData([]byte(name)).AddData(claimID).AddData([]byte(value)).
AddOp(OP_2DROP).AddOp(OP_2DROP).AddOp(OP_TRUE).Script()
}
// ClaimScript represents of one of the ClaimNameScript, ClaimSupportScript, and ClaimUpdateScript.
type ClaimScript struct {
Opcode byte
Name []byte
ClaimID []byte
Value []byte
Size int
}
// ExtractClaimScript exctracts the claim script from the script if it has one.
// The returned ClaimScript is invalidated if the given script is modified.
func ExtractClaimScript(script []byte) (*ClaimScript, error) {
var cs ClaimScript
tokenizer := MakeScriptTokenizer(claimScriptVersion, script)
if !tokenizer.Next() {
return nil, claimScriptError(ErrNotClaimScript, "not a claim script opcode")
}
cs.Opcode = tokenizer.Opcode()
switch tokenizer.Opcode() {
case OP_CLAIMNAME:
// OP_CLAIMNAME <Name> <Value> OP_2DROP OP_DROP <P2PKH>
if !tokenizer.Next() || len(tokenizer.Data()) > MaxClaimNameSize {
str := fmt.Sprintf("name size %d exceeds limit %d", len(tokenizer.data), MaxClaimNameSize)
return nil, claimScriptError(ErrInvalidClaimNameScript, str)
}
cs.Name = tokenizer.data
if !tokenizer.Next() {
return nil, claimScriptError(ErrInvalidClaimNameScript, "expect value")
}
cs.Value = tokenizer.Data()
if !tokenizer.Next() || tokenizer.Opcode() != OP_2DROP ||
!tokenizer.Next() || tokenizer.Opcode() != OP_DROP {
str := fmt.Sprintf("expect OP_2DROP OP_DROP")
return nil, claimScriptError(ErrInvalidClaimNameScript, str)
}
cs.Size = int(tokenizer.ByteIndex())
return &cs, nil
case OP_SUPPORTCLAIM:
// OP_SUPPORTCLAIM <Name> <ClaimID> OP_2DROP OP_DROP <P2PKH>
// OP_SUPPORTCLAIM <Name> <ClaimID> <Value> OP_2DROP OP_2DROP <P2PKH>
if !tokenizer.Next() || len(tokenizer.Data()) > MaxClaimNameSize {
str := fmt.Sprintf("name size %d exceeds limit %d", len(tokenizer.data), MaxClaimNameSize)
return nil, claimScriptError(ErrInvalidClaimSupportScript, str)
}
cs.Name = tokenizer.data
if !tokenizer.Next() || len(tokenizer.Data()) != ClaimIDLength {
str := fmt.Sprintf("expect claim id length %d, instead of %d", ClaimIDLength, len(tokenizer.data))
return nil, claimScriptError(ErrInvalidClaimSupportScript, str)
}
cs.ClaimID = tokenizer.Data()
if !tokenizer.Next() {
return nil, claimScriptError(ErrInvalidClaimSupportScript, "incomplete script")
}
switch {
case tokenizer.Opcode() == OP_2DROP:
// Case 1: OP_SUPPORTCLAIM <Name> <ClaimID> OP_2DROP OP_DROP <P2PKH>
if !tokenizer.Next() || tokenizer.Opcode() != OP_DROP {
str := fmt.Sprintf("expect OP_2DROP OP_DROP")
return nil, claimScriptError(ErrInvalidClaimSupportScript, str)
}
case len(tokenizer.Data()) != 0:
// Case 2: OP_SUPPORTCLAIM <Name> <ClaimID> <Dummy Value> OP_2DROP OP_2DROP <P2PKH>
// (old bug: non-length size dummy value?)
cs.Value = tokenizer.Data()
if !tokenizer.Next() || tokenizer.Opcode() != OP_2DROP ||
!tokenizer.Next() || tokenizer.Opcode() != OP_2DROP {
str := fmt.Sprintf("expect OP_2DROP OP_2DROP")
return nil, claimScriptError(ErrInvalidClaimSupportScript, str)
}
default:
str := fmt.Sprintf("expect OP_2DROP OP_DROP")
return nil, claimScriptError(ErrInvalidClaimSupportScript, str)
}
cs.Size = int(tokenizer.ByteIndex())
return &cs, nil
case OP_UPDATECLAIM:
// OP_UPDATECLAIM <Name> <ClaimID> <Value> OP_2DROP OP_2DROP <P2PKH>
if !tokenizer.Next() || len(tokenizer.Data()) > MaxClaimNameSize {
str := fmt.Sprintf("name size %d exceeds limit %d", len(tokenizer.data), MaxClaimNameSize)
return nil, claimScriptError(ErrInvalidClaimUpdateScript, str)
}
cs.Name = tokenizer.data
if !tokenizer.Next() || len(tokenizer.Data()) != ClaimIDLength {
str := fmt.Sprintf("expect claim id length %d, instead of %d", ClaimIDLength, len(tokenizer.data))
return nil, claimScriptError(ErrInvalidClaimUpdateScript, str)
}
cs.ClaimID = tokenizer.Data()
if !tokenizer.Next() {
str := fmt.Sprintf("expect value")
return nil, claimScriptError(ErrInvalidClaimUpdateScript, str)
}
cs.Value = tokenizer.Data()
if !tokenizer.Next() || tokenizer.Opcode() != OP_2DROP ||
!tokenizer.Next() || tokenizer.Opcode() != OP_2DROP {
str := fmt.Sprintf("expect OP_2DROP OP_2DROP")
return nil, claimScriptError(ErrInvalidClaimUpdateScript, str)
}
cs.Size = int(tokenizer.ByteIndex())
return &cs, nil
default:
return nil, claimScriptError(ErrNotClaimScript, "")
}
}
// StripClaimScriptPrefix strips prefixed claim script, if any.
func StripClaimScriptPrefix(script []byte) []byte {
cs, err := ExtractClaimScript(script)
if err != nil {
return script
}
return script[cs.Size:]
}
const illegalChars = "=&#:*$%?/;\\\b\n\t\r\x00"
func AllClaimsAreSane(script []byte, enforceSoftFork bool) error {
cs, err := ExtractClaimScript(script)
if IsErrorCode(err, ErrNotClaimScript) {
return nil
}
if err != nil {
return err
}
if enforceSoftFork {
if !utf8.Valid(cs.Name) {
return fmt.Errorf("claim name is not valid UTF-8")
}
if bytes.ContainsAny(cs.Name, illegalChars) {
return fmt.Errorf("claim name has illegal chars; it should not contain any of these: %s", illegalChars)
}
}
return nil
}

View file

@ -0,0 +1,80 @@
package txscript
import (
"testing"
"github.com/stretchr/testify/require"
)
func TestCreationParseLoopClaim(t *testing.T) {
r := require.New(t)
// OP_CLAIMNAME <Name> <Value> OP_2DROP OP_DROP <P2PKH>
script, err := ClaimNameScript("tester", "value")
r.NoError(err)
cs, err := ExtractClaimScript(script)
r.NoError(err)
r.Equal(byte(OP_CLAIMNAME), cs.Opcode)
r.Equal([]byte("tester"), cs.Name)
r.Equal([]byte("value"), cs.Value)
}
func TestCreationParseLoopUpdate(t *testing.T) {
r := require.New(t)
claimID := []byte("12345123451234512345")
claim, err := ClaimUpdateScript("tester", claimID, "value")
r.NoError(err)
cs, err := ExtractClaimScript(claim)
r.NoError(err)
r.Equal(byte(OP_UPDATECLAIM), cs.Opcode)
r.Equal([]byte("tester"), cs.Name)
r.Equal(claimID, cs.ClaimID)
r.Equal([]byte("value"), cs.Value)
}
func TestCreationParseLoopSupport(t *testing.T) {
r := require.New(t)
claimID := []byte("12345123451234512345")
// case 1: OP_SUPPORTCLAIM <Name> <ClaimID> OP_2DROP OP_DROP <P2PKH>
script, err := ClaimSupportScript("tester", claimID, nil)
r.NoError(err)
cs, err := ExtractClaimScript(script)
r.NoError(err)
r.Equal(byte(OP_SUPPORTCLAIM), cs.Opcode)
r.Equal([]byte("tester"), cs.Name)
r.Equal(claimID, cs.ClaimID)
r.Nil(cs.Value)
// case 2: OP_SUPPORTCLAIM <Name> <ClaimID> <Value> OP_2DROP OP_2DROP <P2PKH>
script, err = ClaimSupportScript("tester", claimID, []byte("value"))
r.NoError(err)
cs, err = ExtractClaimScript(script)
r.NoError(err)
r.Equal(byte(OP_SUPPORTCLAIM), cs.Opcode)
r.Equal([]byte("tester"), cs.Name)
r.Equal(claimID, cs.ClaimID)
r.Equal([]byte("value"), cs.Value)
}
func TestInvalidChars(t *testing.T) {
r := require.New(t)
script, err := ClaimNameScript("tester", "value")
r.NoError(err)
r.NoError(AllClaimsAreSane(script, true))
for i := range []byte(illegalChars) {
script, err := ClaimNameScript("a"+illegalChars[i:i+1], "value")
r.NoError(err)
r.Error(AllClaimsAreSane(script, true))
}
}