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Merged
ucwong merged 1 commit into from
Jan 31, 2026
Merged

Missing immediate byte is now treated as 0x00 #2628

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24 changes: 12 additions & 12 deletions core/vm/instructions.go
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Original file line number Diff line number Diff line change
Expand Up @@ -1192,11 +1192,11 @@ func opDupN(pc *uint64, evm *CVM, scope *ScopeContext) ([]byte, error) {
code := scope.Contract.Code
i := *pc + 1

// Ensure an immediate byte exists after DUPN
if i >= uint64(len(code)) {
return nil, &ErrInvalidOpCode{opcode: INVALID}
// If the immediate byte is missing, treat as 0x00 (same convention as PUSHn).
var x byte
if i < uint64(len(code)) {
x = code[i]
}
x := code[i]

// This range is excluded to preserve compatibility with existing opcodes.
if x > 90 && x < 128 {
Expand All @@ -1219,11 +1219,11 @@ func opSwapN(pc *uint64, evm *CVM, scope *ScopeContext) ([]byte, error) {
code := scope.Contract.Code
i := *pc + 1

// Ensure an immediate byte exists after SWAPN
if i >= uint64(len(code)) {
return nil, &ErrInvalidOpCode{opcode: INVALID}
// If the immediate byte is missing, treat as 0x00 (same convention as PUSHn).
var x byte
if i < uint64(len(code)) {
x = code[i]
}
x := code[i]

// This range is excluded to preserve compatibility with existing opcodes.
if x > 90 && x < 128 {
Expand All @@ -1248,11 +1248,11 @@ func opExchange(pc *uint64, evm *CVM, scope *ScopeContext) ([]byte, error) {
code := scope.Contract.Code
i := *pc + 1

// Ensure an immediate byte exists after EXCHANGE
if i >= uint64(len(code)) {
return nil, &ErrInvalidOpCode{opcode: INVALID}
// If the immediate byte is missing, treat as 0x00 (same convention as PUSHn).
var x byte
if i < uint64(len(code)) {
x = code[i]
}
x := code[i]

// This range is excluded both to preserve compatibility with existing opcodes
// and to keep decode_pair’s 16-aligned arithmetic mapping valid (0–79, 128–255).
Expand Down
62 changes: 37 additions & 25 deletions core/vm/instructions_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -777,6 +777,15 @@ func TestEIP8024_Execution(t *testing.T) {
1,
},
},
{
name: "DUPN_MISSING_IMMEDIATE",
codeHex: "60016000808080808080808080808080808080e6",
wantVals: []uint64{
1,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
1,
},
},
{
name: "SWAPN",
codeHex: "600160008080808080808080808080808080806002e700",
Expand All @@ -786,11 +795,29 @@ func TestEIP8024_Execution(t *testing.T) {
2,
},
},
{
name: "SWAPN_MISSING_IMMEDIATE",
codeHex: "600160008080808080808080808080808080806002e7",
wantVals: []uint64{
1,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
2,
},
},
{
name: "EXCHANGE",
codeHex: "600060016002e801",
wantVals: []uint64{2, 0, 1},
},
{
name: "EXCHANGE_MISSING_IMMEDIATE",
codeHex: "600060006000600060006000600060006000600060006000600060006000600060006000600060006000600060006000600060006000600060016002e8",
wantVals: []uint64{
2,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
1,
},
},
{
name: "INVALID_SWAPN_LOW",
codeHex: "e75b",
Expand Down Expand Up @@ -842,21 +869,6 @@ func TestEIP8024_Execution(t *testing.T) {
codeHex: "60016002e801", // (n,m)=(1,2), need 3 items, have 2
wantErr: true,
},
{
name: "MISSING_IMMEDIATE_DUPN",
codeHex: "e6", // no operand
wantErr: true,
},
{
name: "MISSING_IMMEDIATE_SWAPN",
codeHex: "e7", // no operand
wantErr: true,
},
{
name: "MISSING_IMMEDIATE_EXCHANGE",
codeHex: "e8", // no operand
wantErr: true,
},
{
name: "PC_INCREMENT",
codeHex: "600060006000e80115",
Expand All @@ -873,25 +885,25 @@ func TestEIP8024_Execution(t *testing.T) {
var err error
for pc < uint64(len(code)) && err == nil {
op := code[pc]
switch op {
case 0x00:
switch OpCode(op) {
case STOP:
return
case 0x60:
case PUSH1:
_, err = opPush1(&pc, evm, scope)
case 0x80:
case DUP1:
dup1 := makeDup(1)
_, err = dup1(&pc, evm, scope)
case 0x56:
case JUMP:
_, err = opJump(&pc, evm, scope)
case 0x5b:
case JUMPDEST:
_, err = opJumpdest(&pc, evm, scope)
case 0x15:
case ISZERO:
_, err = opIszero(&pc, evm, scope)
case 0xe6:
case DUPN:
_, err = opDupN(&pc, evm, scope)
case 0xe7:
case SWAPN:
_, err = opSwapN(&pc, evm, scope)
case 0xe8:
case EXCHANGE:
_, err = opExchange(&pc, evm, scope)
default:
err = &ErrInvalidOpCode{opcode: OpCode(op)}
Expand Down
23 changes: 23 additions & 0 deletions core/vm/opcodes.go
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Original file line number Diff line number Diff line change
Expand Up @@ -206,6 +206,29 @@ const (
LOG4
)

// 0xd0 range - eof operations.
const (
DATALOAD OpCode = 0xd0
DATALOADN OpCode = 0xd1
DATASIZE OpCode = 0xd2
DATACOPY OpCode = 0xd3
)

// 0xe0 range - eof operations.
const (
RJUMP OpCode = 0xe0
RJUMPI OpCode = 0xe1
RJUMPV OpCode = 0xe2
CALLF OpCode = 0xe3
RETF OpCode = 0xe4
JUMPF OpCode = 0xe5
DUPN OpCode = 0xe6
SWAPN OpCode = 0xe7
EXCHANGE OpCode = 0xe8
EOFCREATE OpCode = 0xec
RETURNCONTRACT OpCode = 0xee
)

// 0xf0 range - closures.
const (
CREATE OpCode = 0xf0 + iota
Expand Down
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