You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
99 lines
2.0 KiB
Go
99 lines
2.0 KiB
Go
// Copyright (c) 2020, The Garble Authors.
|
|
// See LICENSE for licensing information.
|
|
|
|
package literals
|
|
|
|
import (
|
|
cryptrand "crypto/rand"
|
|
"fmt"
|
|
"go/ast"
|
|
"go/token"
|
|
mathrand "math/rand"
|
|
"os"
|
|
"strings"
|
|
)
|
|
|
|
// obfuscator takes a byte slice and converts it to a ast.BlockStmt
|
|
type obfuscator interface {
|
|
obfuscate(data []byte) *ast.BlockStmt
|
|
}
|
|
|
|
var (
|
|
// obfuscators contains all types which implement the obfuscator Interface
|
|
obfuscators = []obfuscator{
|
|
simple{},
|
|
swap{},
|
|
split{},
|
|
shuffle{},
|
|
seed{},
|
|
}
|
|
envGarbleSeed = os.Getenv("GARBLE_SEED")
|
|
)
|
|
|
|
// If math/rand.Seed() is not called, the generator behaves as if seeded by rand.Seed(1),
|
|
// so the generator is deterministic.
|
|
|
|
// genRandBytes return a random []byte with the length of size.
|
|
func genRandBytes(buffer []byte) {
|
|
if strings.HasPrefix(envGarbleSeed, "random;") {
|
|
_, err := cryptrand.Read(buffer)
|
|
if err != nil {
|
|
panic(fmt.Sprintf("couldn't generate random key: %v", err))
|
|
}
|
|
} else {
|
|
_, err := mathrand.Read(buffer)
|
|
if err != nil {
|
|
panic(fmt.Sprintf("couldn't generate random key: %v", err))
|
|
}
|
|
}
|
|
}
|
|
|
|
func genRandByte() byte {
|
|
bytes := make([]byte, 1)
|
|
genRandBytes(bytes)
|
|
return bytes[0]
|
|
}
|
|
|
|
func genRandIntSlice(max, count int) []int {
|
|
indexes := make([]int, count)
|
|
for i := 0; i < count; i++ {
|
|
indexes[i] = mathrand.Intn(max)
|
|
}
|
|
return indexes
|
|
}
|
|
|
|
func randOperator() token.Token {
|
|
operatorTokens := [...]token.Token{token.XOR, token.ADD, token.SUB}
|
|
return operatorTokens[mathrand.Intn(len(operatorTokens))]
|
|
}
|
|
|
|
func evalOperator(t token.Token, x, y byte) byte {
|
|
switch t {
|
|
case token.XOR:
|
|
return x ^ y
|
|
case token.ADD:
|
|
return x + y
|
|
case token.SUB:
|
|
return x - y
|
|
default:
|
|
panic(fmt.Sprintf("unknown operator: %s", t))
|
|
}
|
|
}
|
|
|
|
func operatorToReversedBinaryExpr(t token.Token, x, y ast.Expr) *ast.BinaryExpr {
|
|
expr := &ast.BinaryExpr{X: x, Y: y}
|
|
|
|
switch t {
|
|
case token.XOR:
|
|
expr.Op = token.XOR
|
|
case token.ADD:
|
|
expr.Op = token.SUB
|
|
case token.SUB:
|
|
expr.Op = token.ADD
|
|
default:
|
|
panic(fmt.Sprintf("unknown operator: %s", t))
|
|
}
|
|
|
|
return expr
|
|
}
|