core: vm: vm interface (#164)

1 files changed, 158 insertions, 0 deletions

diff --git a/core/vm/tools/patch.go b/core/vm/tools/patch.go
new file mode 100644
index 000000000..7d41fcc98
--- /dev/null
+++ b/core/vm/tools/patch.go
@@ -0,0 +1,158 @@
+package tools
+
+import (
+	"encoding/binary"
+	"encoding/hex"
+	"regexp"
+)
+
+func PatchBinary(input []byte) []byte {
+	if input == nil {
+		return nil
+	}
+	stringCode := hex.EncodeToString(input)
+	stringCode = Patch(stringCode)
+	result, _ := hex.DecodeString(stringCode)
+	return result
+}
+func patchPattern1(input string) string {
+	// Case 1
+	// PUSH1 v1 DUP1 PUSH1 v2 PUSH1 v3 CODECOPY
+	// we have to set v1 = v1 + 1
+	r, _ := regexp.Compile("60..8060..60..39")
+	loc := r.FindStringIndex(input)
+	if len(loc) > 0 {
+		valLoc := loc[0]/2 + 1
+		bString, _ := hex.DecodeString(input)
+		bString[valLoc]++
+		input = hex.EncodeToString(bString)
+	}
+	return input
+}
+func patchPattern2(input string) string {
+	// Case 2
+	// PUSH2 v1 v2 DUP1 PUSH2 v3 PUSH1 v4 CODECOPY
+	// we have to set BigEndian(v1,v2)++
+	r, _ := regexp.Compile("61....8061....60..39")
+	loc := r.FindStringIndex(input)
+	if len(loc) > 0 {
+		valLoc := loc[0]/2 + 1
+		bString, _ := hex.DecodeString(input)
+		val := binary.BigEndian.Uint16(bString[valLoc : valLoc+2])
+		val++
+		binary.BigEndian.PutUint16(bString[valLoc:], val)
+		input = hex.EncodeToString(bString)
+	}
+	return input
+}
+func patchPattern3(input string) string {
+	// Case 3
+	// PUSH1 v1 DUP1 PUSH3 v2 v3 v4 DUP4 CODECOPY
+	// we have to set BigEndian(v2,v3,v4)++
+	r, _ := regexp.Compile("60..8062......8339")
+	loc := r.FindStringIndex(input)
+	if len(loc) > 0 {
+		valLoc := loc[0]/2 + 4
+		bString, _ := hex.DecodeString(input)
+		toConvert := append([]byte{0}, bString[valLoc:valLoc+3]...)
+		tmpBinary := make([]byte, 4)
+		val := binary.BigEndian.Uint32(toConvert)
+		val--
+		binary.BigEndian.PutUint32(tmpBinary, val)
+		bString[valLoc] = tmpBinary[1]
+		bString[valLoc+1] = tmpBinary[2]
+		bString[valLoc+2] = tmpBinary[3]
+		input = hex.EncodeToString(bString)
+	}
+	return input
+}
+func patchPattern4(input string) string {
+	// Case 4
+	// PUSH2 v1 v2 DUP1 PUSH2 v3 DUP4 CODECOPY
+	// we have to set BigEndian(v1,v2)+2
+	r, _ := regexp.Compile("61....8061....8339")
+	loc := r.FindStringIndex(input)
+	if len(loc) > 0 {
+		valLoc := loc[0]/2 + 1
+		bString, _ := hex.DecodeString(input)
+		val := binary.BigEndian.Uint16(bString[valLoc : valLoc+2])
+		val = val + 2
+		binary.BigEndian.PutUint16(bString[valLoc:], val)
+		input = hex.EncodeToString(bString)
+	}
+	return input
+}
+func patchPattern5(input string) string {
+	// Case 5
+	// PUSH1 v1 DUP1 PUSH2 v2 v3 DUP4 CODECOPY
+	// we have to set BigEndian(v2,v3)++
+	r, _ := regexp.Compile("60..8061....8339")
+	loc := r.FindStringIndex(input)
+	if len(loc) > 0 {
+		valLoc := loc[0]/2 + 4
+		bString, _ := hex.DecodeString(input)
+		val := binary.BigEndian.Uint16(bString[valLoc : valLoc+2])
+		val = val + 1
+		binary.BigEndian.PutUint16(bString[valLoc:], val)
+		input = hex.EncodeToString(bString)
+	}
+	return input
+}
+func patchPattern6(input string) string {
+	// Case 6
+	// SUB DUP1 PUSH2 v2 v3 DUP4 CODECOPY
+	// we have to set BigEndian(v2,v3)++
+	r, _ := regexp.Compile("038061....8339")
+	loc := r.FindStringIndex(input)
+	if len(loc) > 0 {
+		valLoc := loc[0]/2 + 3
+		bString, _ := hex.DecodeString(input)
+		val := binary.BigEndian.Uint16(bString[valLoc : valLoc+2])
+		val = val + 1
+		binary.BigEndian.PutUint16(bString[valLoc:], val)
+		input = hex.EncodeToString(bString)
+	}
+	return input
+}
+func addPrefix(input string) string {
+	r, _ := regexp.Compile("6060604052")
+	loc := r.FindAllStringIndex(input, -1)
+	if len(loc) > 0 {
+		for i, offset := range loc {
+			insertLoc := offset[0] + i*2
+			if !isDelegateCall(input, insertLoc) {
+				input = input[:insertLoc] + "00" + input[insertLoc:]
+			}
+		}
+		if input[0:2] != "00" {
+			input = "00" + input
+		}
+	}
+	return input
+}
+func isDelegateCall(input string, codeStartAt int) bool {
+	delegateCallPrefix := "6504032353da7150"
+	prefixLen := len(delegateCallPrefix)
+	newStartAt := codeStartAt - prefixLen
+	if newStartAt >= 0 {
+		if input[newStartAt:newStartAt+prefixLen] == delegateCallPrefix {
+			return true
+		}
+	}
+	return false
+}
+
+// Patch patch lagacy bytecode(hex string) to new vm interface compatible bytecode
+func Patch(input string) string {
+	if len(input) == 0 {
+		return input
+	}
+	input = patchPattern1(input)
+	input = patchPattern2(input)
+	input = patchPattern3(input)
+	input = patchPattern4(input)
+	input = patchPattern5(input)
+	input = patchPattern6(input)
+	result := addPrefix(input)
+	return result
+}