1080 lines
26 KiB
Markdown
1080 lines
26 KiB
Markdown
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---
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id: Go 安全指南
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title: Go 安全指南
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sidebar_position: 4
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data: 2022年5月30日
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---
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## 1. 代码实现类
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### 1.1 内存管理
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#### 1.1.1 切片长度校验
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- 在对slice进行操作时，必须判断长度是否合法，防止程序panic
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```go
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// bad: 未判断data的长度，可导致 index out of range
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func decode(data []byte) bool {
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if data[0] == 'F' && data[1] == 'U' && data[2] == 'Z' && data[3] == 'Z' && data[4] == 'E' && data[5] == 'R' {
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fmt.Println("Bad")
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return true
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}
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return false
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}
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// bad: slice bounds out of range
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func foo() {
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var slice = []int{0, 1, 2, 3, 4, 5, 6}
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fmt.Println(slice[:10])
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}
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// good: 使用data前应判断长度是否合法
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func decode(data []byte) bool {
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if len(data) == 6 {
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if data[0] == 'F' && data[1] == 'U' && data[2] == 'Z' && data[3] == 'Z' && data[4] == 'E' && data[5] == 'R' {
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fmt.Println("Good")
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return true
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}
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}
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return false
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}
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```
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#### 1.1.2 nil指针判断
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- 进行指针操作时，必须判断该指针是否为nil，防止程序panic，尤其在进行结构体Unmarshal时
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```go
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type Packet struct {
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PackeyType uint8
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PackeyVersion uint8
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Data *Data
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}
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type Data struct {
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Stat uint8
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Len uint8
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Buf [8]byte
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}
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func (p *Packet) UnmarshalBinary(b []byte) error {
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if len(b) < 2 {
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return io.EOF
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}
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p.PackeyType = b[0]
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p.PackeyVersion = b[1]
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// 若长度等于2，那么不会new Data
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if len(b) > 2 {
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p.Data = new(Data)
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}
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return nil
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}
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// bad: 未判断指针是否为nil
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func main() {
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packet := new(Packet)
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data := make([]byte, 2)
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if err := packet.UnmarshalBinary(data); err != nil {
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fmt.Println("Failed to unmarshal packet")
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return
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}
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fmt.Printf("Stat: %v\n", packet.Data.Stat)
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}
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// good: 判断Data指针是否为nil
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func main() {
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packet := new(Packet)
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data := make([]byte, 2)
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if err := packet.UnmarshalBinary(data); err != nil {
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fmt.Println("Failed to unmarshal packet")
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return
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}
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if packet.Data == nil {
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return
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}
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fmt.Printf("Stat: %v\n", packet.Data.Stat)
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}
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```
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#### 1.1.3 整数安全
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- 在进行数字运算操作时，需要做好长度限制，防止外部输入运算导致异常：
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- 确保无符号整数运算时不会反转
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- 确保有符号整数运算时不会出现溢出
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- 确保整型转换时不会出现截断错误
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- 确保整型转换时不会出现符号错误
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- 以下场景必须严格进行长度限制：
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- 作为数组索引
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- 作为对象的长度或者大小
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- 作为数组的边界（如作为循环计数器）
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```go
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// bad: 未限制长度，导致整数溢出
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func overflow(numControlByUser int32) {
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var numInt int32 = 0
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numInt = numControlByUser + 1
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// 对长度限制不当，导致整数溢出
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fmt.Printf("%d\n", numInt)
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// 使用numInt，可能导致其他错误
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}
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func main() {
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overflow(2147483647)
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}
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// good
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func overflow(numControlByUser int32) {
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var numInt int32 = 0
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numInt = numControlByUser + 1
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if numInt < 0 {
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fmt.Println("integer overflow")
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return
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}
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fmt.Println("integer ok")
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}
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func main() {
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overflow(2147483647)
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}
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```
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#### 1.1.4 make分配长度验证
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- 在进行make分配内存时，需要对外部可控的长度进行校验，防止程序panic。
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```go
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// bad
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func parse(lenControlByUser int, data []byte) {
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size := lenControlByUser
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// 对外部传入的size，进行长度判断以免导致panic
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buffer := make([]byte, size)
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copy(buffer, data)
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}
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// good
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func parse(lenControlByUser int, data []byte) ([]byte, error) {
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size := lenControlByUser
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// 限制外部可控的长度大小范围
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if size > 64*1024*1024 {
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return nil, errors.New("value too large")
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}
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buffer := make([]byte, size)
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copy(buffer, data)
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return buffer, nil
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}
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```
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#### 1.1.5 禁止SetFinalizer和指针循环引用同时使用
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- 当一个对象从被GC选中到移除内存之前，runtime.SetFinalizer()都不会执行，即使程序正常结束或者发生错误。由指针构成的“循环引用”虽然能被GC正确处理，但由于无法确定Finalizer依赖顺序，从而无法调用runtime.SetFinalizer()，导致目标对象无法变成可达状态，从而造成内存无法被回收。
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```go
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// bad
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func foo() {
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var a, b Data
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a.o = &b
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b.o = &a
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// 指针循环引用，SetFinalizer()无法正常调用
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runtime.SetFinalizer(&a, func(d *Data) {
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fmt.Printf("a %p final.\n", d)
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})
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runtime.SetFinalizer(&b, func(d *Data) {
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fmt.Printf("b %p final.\n", d)
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})
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}
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func main() {
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for {
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foo()
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time.Sleep(time.Millisecond)
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}
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}
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```
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#### 1.1.6 禁止重复释放channel
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- 重复释放一般存在于异常流程判断中，如果恶意攻击者构造出异常条件使程序重复释放channel，则会触发运行时panic，从而造成DoS攻击。
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```go
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// bad
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func foo(c chan int) {
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defer close(c)
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err := processBusiness()
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if err != nil {
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c <- 0
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close(c) // 重复释放channel
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return
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}
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c <- 1
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}
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// good
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func foo(c chan int) {
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defer close(c) // 使用defer延迟关闭channel
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err := processBusiness()
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if err != nil {
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c <- 0
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return
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}
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c <- 1
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}
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```
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#### 1.1.7 确保每个协程都能退出
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- 启动一个协程就会做一个入栈操作，在系统不退出的情况下，协程也没有设置退出条件，则相当于协程失去了控制，它占用的资源无法回收，可能会导致内存泄露。
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```go
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// bad: 协程没有设置退出条件
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func doWaiter(name string, second int) {
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for {
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time.Sleep(time.Duration(second) * time.Second)
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fmt.Println(name, " is ready!")
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}
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}
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```
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#### 1.1.8【推荐】不使用unsafe包
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- 由于unsafe包绕过了 Golang 的内存安全原则，一般来说使用该库是不安全的，可导致内存破坏，尽量避免使用该包。若必须要使用unsafe操作指针，必须做好安全校验。
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```go
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// bad: 通过unsafe操作原始指针
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func unsafePointer() {
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b := make([]byte, 1)
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foo := (*int)(unsafe.Pointer(uintptr(unsafe.Pointer(&b[0])) + uintptr(0xfffffffe)))
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fmt.Print(*foo + 1)
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}
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// [signal SIGSEGV: segmentation violation code=0x1 addr=0xc100068f55 pc=0x49142b]
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```
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#### 1.1.9【推荐】不使用slice作为函数入参
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- slice在作为函数入参时，函数内对slice的修改可能会影响原始数据
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```go
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// bad
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// slice作为函数入参时包含原始数组指针
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func modify(array []int) {
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array[0] = 10 // 对入参slice的元素修改会影响原始数据
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}
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func main() {
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array := []int{1, 2, 3, 4, 5}
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modify(array)
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fmt.Println(array) // output：[10 2 3 4 5]
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}
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// good
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// 数组作为函数入参，而不是slice
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func modify(array [5]int) {
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array[0] = 10
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}
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func main() {
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// 传入数组，注意数组与slice的区别
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array := [5]int{1, 2, 3, 4, 5}
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modify(array)
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fmt.Println(array)
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}
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```
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### 1.2 文件操作
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#### 1.2.1 路径穿越检查
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- 在进行文件操作时，如果对外部传入的文件名未做限制，可能导致任意文件读取或者任意文件写入，严重可能导致代码执行。
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```go
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// bad: 任意文件读取
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func handler(w http.ResponseWriter, r *http.Request) {
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path := r.URL.Query()["path"][0]
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// 未过滤文件路径，可能导致任意文件读取
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data, _ := ioutil.ReadFile(path)
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w.Write(data)
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// 对外部传入的文件名变量，还需要验证是否存在../等路径穿越的文件名
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data, _ = ioutil.ReadFile(filepath.Join("/home/user/", path))
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w.Write(data)
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}
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// bad: 任意文件写入
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func unzip(f string) {
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r, _ := zip.OpenReader(f)
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for _, f := range r.File {
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p, _ := filepath.Abs(f.Name)
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// 未验证压缩文件名，可能导致../等路径穿越，任意文件路径写入
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ioutil.WriteFile(p, []byte("present"), 0640)
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}
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}
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// good: 检查压缩的文件名是否包含..路径穿越特征字符，防止任意写入
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func unzipGood(f string) bool {
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r, err := zip.OpenReader(f)
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if err != nil {
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fmt.Println("read zip file fail")
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return false
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}
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for _, f := range r.File {
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if !strings.Contains(f.Name, "..") {
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p, _ := filepath.Abs(f.Name)
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ioutil.WriteFile(p, []byte("present"), 0640)
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} else {
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return false
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}
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}
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return true
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}
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```
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#### 1.2.2 文件访问权限
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|
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|
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- 根据创建文件的敏感性设置不同级别的访问权限，以防止敏感数据被任意权限用户读取。例如，设置文件权限为：`-rw-r-----`
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```go
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|
|
ioutil.WriteFile(p, []byte("present"), 0640)
|
|||
|
|
```
|
|||
|
|
|
|||
|
|
### 1.3 系统接口
|
|||
|
|
|
|||
|
|
#### 1.3.1【必须】命令执行检查
|
|||
|
|
|
|||
|
|
- 使用`exec.Command`、`exec.CommandContext`、`syscall.StartProcess`、`os.StartProcess`等函数时，第一个参数（path）直接取外部输入值时，应使用白名单限定可执行的命令范围，不允许传入`bash`、`cmd`、`sh`等命令；
|
|||
|
|
- 使用`exec.Command`、`exec.CommandContext`等函数时，通过`bash`、`cmd`、`sh`等创建shell，-c后的参数（arg）拼接外部输入，应过滤\n $ & ; | ' " ( ) `等潜在恶意字符；
|
|||
|
|
|
|||
|
|
```go
|
|||
|
|
// bad
|
|||
|
|
func foo() {
|
|||
|
|
userInputedVal := "&& echo 'hello'" // 假设外部传入该变量值
|
|||
|
|
cmdName := "ping " + userInputedVal
|
|||
|
|
|
|||
|
|
// 未判断外部输入是否存在命令注入字符，结合sh可造成命令注入
|
|||
|
|
cmd := exec.Command("sh", "-c", cmdName)
|
|||
|
|
output, _ := cmd.CombinedOutput()
|
|||
|
|
fmt.Println(string(output))
|
|||
|
|
|
|||
|
|
cmdName := "ls"
|
|||
|
|
// 未判断外部输入是否是预期命令
|
|||
|
|
cmd := exec.Command(cmdName)
|
|||
|
|
output, _ := cmd.CombinedOutput()
|
|||
|
|
fmt.Println(string(output))
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
// good
|
|||
|
|
func checkIllegal(cmdName string) bool {
|
|||
|
|
if strings.Contains(cmdName, "&") || strings.Contains(cmdName, "|") || strings.Contains(cmdName, ";") ||
|
|||
|
|
strings.Contains(cmdName, "$") || strings.Contains(cmdName, "'") || strings.Contains(cmdName, "`") ||
|
|||
|
|
strings.Contains(cmdName, "(") || strings.Contains(cmdName, ")") || strings.Contains(cmdName, "\"") {
|
|||
|
|
return true
|
|||
|
|
}
|
|||
|
|
return false
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
func main() {
|
|||
|
|
userInputedVal := "&& echo 'hello'"
|
|||
|
|
cmdName := "ping " + userInputedVal
|
|||
|
|
|
|||
|
|
if checkIllegal(cmdName) { // 检查传给sh的命令是否有特殊字符
|
|||
|
|
return // 存在特殊字符直接return
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
cmd := exec.Command("sh", "-c", cmdName)
|
|||
|
|
output, _ := cmd.CombinedOutput()
|
|||
|
|
fmt.Println(string(output))
|
|||
|
|
}
|
|||
|
|
```
|
|||
|
|
|
|||
|
|
### 1.4 通信安全
|
|||
|
|
|
|||
|
|
#### 1.4.1 网络通信采用TLS方式
|
|||
|
|
|
|||
|
|
- 明文传输的通信协议目前已被验证存在较大安全风险，被中间人劫持后可能导致许多安全风险，因此必须采用至少TLS的安全通信方式保证通信安全，例如gRPC/Websocket都使用TLS1.3。
|
|||
|
|
|
|||
|
|
```go
|
|||
|
|
// good
|
|||
|
|
func main() {
|
|||
|
|
http.HandleFunc("/", func(w http.ResponseWriter, req *http.Request) {
|
|||
|
|
w.Header().Add("Strict-Transport-Security", "max-age=63072000; includeSubDomains")
|
|||
|
|
w.Write([]byte("This is an example server.\n"))
|
|||
|
|
})
|
|||
|
|
|
|||
|
|
// 服务器配置证书与私钥
|
|||
|
|
log.Fatal(http.ListenAndServeTLS(":443", "yourCert.pem", "yourKey.pem", nil))
|
|||
|
|
}
|
|||
|
|
```
|
|||
|
|
|
|||
|
|
#### 1.4.2【推荐】TLS启用证书验证
|
|||
|
|
|
|||
|
|
- TLS证书应当是有效的、未过期的，且配置正确的域名，生产环境的服务端应启用证书验证。
|
|||
|
|
|
|||
|
|
```go
|
|||
|
|
// bad
|
|||
|
|
import (
|
|||
|
|
"crypto/tls"
|
|||
|
|
"net/http"
|
|||
|
|
)
|
|||
|
|
|
|||
|
|
func doAuthReq(authReq *http.Request) *http.Response {
|
|||
|
|
tr := &http.Transport{
|
|||
|
|
TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
|
|||
|
|
}
|
|||
|
|
client := &http.Client{Transport: tr}
|
|||
|
|
res, _ := client.Do(authReq)
|
|||
|
|
return res
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
// good
|
|||
|
|
import (
|
|||
|
|
"crypto/tls"
|
|||
|
|
"net/http"
|
|||
|
|
)
|
|||
|
|
|
|||
|
|
func doAuthReq(authReq *http.Request) *http.Response {
|
|||
|
|
tr := &http.Transport{
|
|||
|
|
TLSClientConfig: &tls.Config{InsecureSkipVerify: false},
|
|||
|
|
}
|
|||
|
|
client := &http.Client{Transport: tr}
|
|||
|
|
res, _ := client.Do(authReq)
|
|||
|
|
return res
|
|||
|
|
}
|
|||
|
|
```
|
|||
|
|
|
|||
|
|
### 1.5 敏感数据保护
|
|||
|
|
|
|||
|
|
#### 1.5.1 敏感信息访问
|
|||
|
|
|
|||
|
|
- 禁止将敏感信息硬编码在程序中，既可能会将敏感信息暴露给攻击者，也会增加代码管理和维护的难度
|
|||
|
|
- 使用配置中心系统统一托管密钥等敏感信息
|
|||
|
|
|
|||
|
|
#### 1.5.2 敏感数据输出
|
|||
|
|
|
|||
|
|
- 只输出必要的最小数据集，避免多余字段暴露引起敏感信息泄露
|
|||
|
|
- 不能在日志保存密码（包括明文密码和密文密码）、密钥和其它敏感信息
|
|||
|
|
- 对于必须输出的敏感信息，必须进行合理脱敏展示
|
|||
|
|
|
|||
|
|
```go
|
|||
|
|
// bad
|
|||
|
|
func serve() {
|
|||
|
|
http.HandleFunc("/register", func(w http.ResponseWriter, r *http.Request) {
|
|||
|
|
r.ParseForm()
|
|||
|
|
user := r.Form.Get("user")
|
|||
|
|
pw := r.Form.Get("password")
|
|||
|
|
|
|||
|
|
log.Printf("Registering new user %s with password %s.\n", user, pw)
|
|||
|
|
})
|
|||
|
|
http.ListenAndServe(":80", nil)
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
// good
|
|||
|
|
func serve1() {
|
|||
|
|
http.HandleFunc("/register", func(w http.ResponseWriter, r *http.Request) {
|
|||
|
|
r.ParseForm()
|
|||
|
|
user := r.Form.Get("user")
|
|||
|
|
pw := r.Form.Get("password")
|
|||
|
|
|
|||
|
|
log.Printf("Registering new user %s.\n", user)
|
|||
|
|
|
|||
|
|
// ...
|
|||
|
|
use(pw)
|
|||
|
|
})
|
|||
|
|
http.ListenAndServe(":80", nil)
|
|||
|
|
}
|
|||
|
|
```
|
|||
|
|
|
|||
|
|
- 避免通过GET方法、代码注释、自动填充、缓存等方式泄露敏感信息
|
|||
|
|
|
|||
|
|
#### 1.5.3 敏感数据存储
|
|||
|
|
|
|||
|
|
- 敏感数据应使用SHA2、RSA等算法进行加密存储
|
|||
|
|
- 敏感数据应使用独立的存储层，并在访问层开启访问控制
|
|||
|
|
- 包含敏感信息的临时文件或缓存一旦不再需要应立刻删除
|
|||
|
|
|
|||
|
|
#### 1.5.4 异常处理和日志记录
|
|||
|
|
|
|||
|
|
- 应合理使用panic、recover、defer处理系统异常，避免出错信息输出到前端
|
|||
|
|
|
|||
|
|
```go
|
|||
|
|
defer func () {
|
|||
|
|
if r := recover(); r != nil {
|
|||
|
|
fmt.Println("Recovered in start()")
|
|||
|
|
}
|
|||
|
|
}()
|
|||
|
|
```
|
|||
|
|
|
|||
|
|
- 对外环境禁止开启debug模式，或将程序运行日志输出到前端
|
|||
|
|
|
|||
|
|
```bash
|
|||
|
|
// bad
|
|||
|
|
dlv --listen=:2345 --headless=true --api-version=2 debug test.go
|
|||
|
|
// good
|
|||
|
|
dlv debug test.go
|
|||
|
|
```
|
|||
|
|
|
|||
|
|
### 1.6 加密解密
|
|||
|
|
|
|||
|
|
#### 1.6.1 不得硬编码密码/密钥
|
|||
|
|
|
|||
|
|
- 在进行用户登陆，加解密算法等操作时，不得在代码里硬编码密钥或密码，可通过变换算法或者配置等方式设置密码或者密钥。
|
|||
|
|
|
|||
|
|
```go
|
|||
|
|
// bad
|
|||
|
|
const (
|
|||
|
|
user = "dbuser"
|
|||
|
|
password = "s3cretp4ssword"
|
|||
|
|
)
|
|||
|
|
|
|||
|
|
func connect() *sql.DB {
|
|||
|
|
connStr := fmt.Sprintf("postgres://%s:%s@localhost/pqgotest", user, password)
|
|||
|
|
db, err := sql.Open("postgres", connStr)
|
|||
|
|
if err != nil {
|
|||
|
|
return nil
|
|||
|
|
}
|
|||
|
|
return db
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
// bad
|
|||
|
|
var (
|
|||
|
|
commonkey = []byte("0123456789abcdef")
|
|||
|
|
)
|
|||
|
|
|
|||
|
|
func AesEncrypt(plaintext string) (string, error) {
|
|||
|
|
block, err := aes.NewCipher(commonkey)
|
|||
|
|
if err != nil {
|
|||
|
|
return "", err
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
```
|
|||
|
|
|
|||
|
|
#### 1.6.2 密钥存储安全
|
|||
|
|
|
|||
|
|
- 在使用对称密码算法时，需要保护好加密密钥。当算法涉及敏感、业务数据时，可通过非对称算法协商加密密钥。其他较为不敏感的数据加密，可以通过变换算法等方式保护密钥。
|
|||
|
|
|
|||
|
|
#### 1.6.3 不使用弱密码算法
|
|||
|
|
|
|||
|
|
- 在使用加密算法时，不建议使用加密强度较弱的算法。
|
|||
|
|
|
|||
|
|
```text
|
|||
|
|
// bad
|
|||
|
|
crypto/des，crypto/md5，crypto/sha1，crypto/rc4等。
|
|||
|
|
|
|||
|
|
// good
|
|||
|
|
crypto/rsa，crypto/aes等。
|
|||
|
|
```
|
|||
|
|
|
|||
|
|
### 1.7 正则表达式
|
|||
|
|
|
|||
|
|
#### 1.7.1【推荐】使用regexp进行正则表达式匹配
|
|||
|
|
|
|||
|
|
- 正则表达式编写不恰当可被用于DoS攻击，造成服务不可用，推荐使用regexp包进行正则表达式匹配。regexp保证了线性时间性能和优雅的失败：对解析器、编译器和执行引擎都进行了内存限制。但regexp不支持以下正则表达式特性，如业务依赖这些特性，则regexp不适合使用。
|
|||
|
|
- 回溯引用[Backreferences](https://www.regular-expressions.info/backref.html)
|
|||
|
|
- 查看[Lookaround](https://www.regular-expressions.info/lookaround.html)
|
|||
|
|
|
|||
|
|
```go
|
|||
|
|
// good
|
|||
|
|
matched, err := regexp.MatchString(`a.b`, "aaxbb")
|
|||
|
|
fmt.Println(matched) // true
|
|||
|
|
fmt.Println(err) // nil
|
|||
|
|
```
|
|||
|
|
|
|||
|
|
# 后台类
|
|||
|
|
|
|||
|
|
## 1 代码实现类
|
|||
|
|
|
|||
|
|
### 1.1 输入校验
|
|||
|
|
|
|||
|
|
#### 1.1.1 按类型进行数据校验
|
|||
|
|
|
|||
|
|
- 所有外部输入的参数，应使用`validator`进行白名单校验，校验内容包括但不限于数据长度、数据范围、数据类型与格式，校验不通过的应当拒绝
|
|||
|
|
|
|||
|
|
```go
|
|||
|
|
// good
|
|||
|
|
import (
|
|||
|
|
"fmt"
|
|||
|
|
"github.com/go-playground/validator/v10"
|
|||
|
|
)
|
|||
|
|
|
|||
|
|
var validate *validator.Validate
|
|||
|
|
|
|||
|
|
func validateVariable() {
|
|||
|
|
myEmail := "abc@tencent.com"
|
|||
|
|
errs := validate.Var(myEmail, "required,email")
|
|||
|
|
if errs != nil {
|
|||
|
|
fmt.Println(errs)
|
|||
|
|
return
|
|||
|
|
//停止执行
|
|||
|
|
}
|
|||
|
|
// 验证通过，继续执行
|
|||
|
|
...
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
func main() {
|
|||
|
|
validate = validator.New()
|
|||
|
|
validateVariable()
|
|||
|
|
}
|
|||
|
|
```
|
|||
|
|
|
|||
|
|
- 无法通过白名单校验的应使用`html.EscapeString`、`text/template`或`bluemonday`对`<, >, &, ',"`等字符进行过滤或编码
|
|||
|
|
|
|||
|
|
```go
|
|||
|
|
import (
|
|||
|
|
"text/template"
|
|||
|
|
)
|
|||
|
|
|
|||
|
|
// TestHTMLEscapeString HTML特殊字符转义
|
|||
|
|
func main(inputValue string) string {
|
|||
|
|
escapedResult := template.HTMLEscapeString(inputValue)
|
|||
|
|
return escapedResult
|
|||
|
|
}
|
|||
|
|
```
|
|||
|
|
|
|||
|
|
### 1.2 SQL操作
|
|||
|
|
|
|||
|
|
#### 1.2.1 SQL语句默认使用预编译并绑定变量
|
|||
|
|
|
|||
|
|
- 使用`database/sql`的prepare、Query或使用GORM等ORM执行SQL操作
|
|||
|
|
|
|||
|
|
```go
|
|||
|
|
import (
|
|||
|
|
"github.com/jinzhu/gorm"
|
|||
|
|
_ "github.com/jinzhu/gorm/dialects/sqlite"
|
|||
|
|
)
|
|||
|
|
|
|||
|
|
type Product struct {
|
|||
|
|
gorm.Model
|
|||
|
|
Code string
|
|||
|
|
Price uint
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
...
|
|||
|
|
var product Product
|
|||
|
|
...
|
|||
|
|
db.First(&product, 1)
|
|||
|
|
```
|
|||
|
|
|
|||
|
|
- 使用参数化查询，禁止拼接SQL语句，另外对于传入参数用于order by或表名的需要通过校验
|
|||
|
|
|
|||
|
|
```go
|
|||
|
|
// bad
|
|||
|
|
import (
|
|||
|
|
"database/sql"
|
|||
|
|
"fmt"
|
|||
|
|
"net/http"
|
|||
|
|
)
|
|||
|
|
|
|||
|
|
func handler(db *sql.DB, req *http.Request) {
|
|||
|
|
q := fmt.Sprintf("SELECT ITEM,PRICE FROM PRODUCT WHERE ITEM_CATEGORY='%s' ORDER BY PRICE",
|
|||
|
|
req.URL.Query()["category"])
|
|||
|
|
db.Query(q)
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
// good
|
|||
|
|
func handlerGood(db *sql.DB, req *http.Request) {
|
|||
|
|
// 使用?占位符
|
|||
|
|
q := "SELECT ITEM,PRICE FROM PRODUCT WHERE ITEM_CATEGORY='?' ORDER BY PRICE"
|
|||
|
|
db.Query(q, req.URL.Query()["category"])
|
|||
|
|
}
|
|||
|
|
```
|
|||
|
|
|
|||
|
|
### 1.3 网络请求
|
|||
|
|
|
|||
|
|
#### 1.3.1 资源请求过滤验证
|
|||
|
|
|
|||
|
|
- 使用`"net/http"`下的方法`http.Get(url)`、`http.Post(url, contentType, body)`、`http.Head(url)`、`http.PostForm(url, data)`、`http.Do(req)`时，如变量值外部可控（指从参数中动态获取），应对请求目标进行严格的安全校验。
|
|||
|
|
|
|||
|
|
- 如请求资源域名归属固定的范围，如只允许`a.qq.com`和`b.qq.com`，应做白名单限制。如不适用白名单，则推荐的校验逻辑步骤是：
|
|||
|
|
|
|||
|
|
- 第 1 步、只允许HTTP或HTTPS协议
|
|||
|
|
|
|||
|
|
- 第 2 步、解析目标URL，获取其HOST
|
|||
|
|
|
|||
|
|
- 第 3 步、解析HOST，获取HOST指向的IP地址转换成Long型
|
|||
|
|
|
|||
|
|
- 第 4 步、检查IP地址是否为内网IP，网段有：
|
|||
|
|
|
|||
|
|
```text
|
|||
|
|
// 以RFC定义的专有网络为例，如有自定义私有网段亦应加入禁止访问列表。
|
|||
|
|
10.0.0.0/8
|
|||
|
|
172.16.0.0/12
|
|||
|
|
192.168.0.0/16
|
|||
|
|
127.0.0.0/8
|
|||
|
|
```
|
|||
|
|
|
|||
|
|
- 第 5 步、请求URL
|
|||
|
|
|
|||
|
|
- 第 6 步、如有跳转，跳转后执行1，否则绑定经校验的ip和域名，对URL发起请求
|
|||
|
|
|
|||
|
|
- 官方库`encoding/xml`不支持外部实体引用，使用该库可避免xxe漏洞
|
|||
|
|
|
|||
|
|
```go
|
|||
|
|
import (
|
|||
|
|
"encoding/xml"
|
|||
|
|
"fmt"
|
|||
|
|
"os"
|
|||
|
|
)
|
|||
|
|
|
|||
|
|
func main() {
|
|||
|
|
type Person struct {
|
|||
|
|
XMLName xml.Name `xml:"person"`
|
|||
|
|
Id int `xml:"id,attr"`
|
|||
|
|
UserName string `xml:"name>first"`
|
|||
|
|
Comment string `xml:",comment"`
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
v := &Person{Id: 13, UserName: "John"}
|
|||
|
|
v.Comment = " Need more details. "
|
|||
|
|
|
|||
|
|
enc := xml.NewEncoder(os.Stdout)
|
|||
|
|
enc.Indent(" ", " ")
|
|||
|
|
if err := enc.Encode(v); err != nil {
|
|||
|
|
fmt.Printf("error: %v\n", err)
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
}
|
|||
|
|
```
|
|||
|
|
|
|||
|
|
### 1.4 服务器端渲染
|
|||
|
|
|
|||
|
|
#### 1.4.1 模板渲染过滤验证
|
|||
|
|
|
|||
|
|
- 使用`text/template`或者`html/template`渲染模板时禁止将外部输入参数引入模板，或仅允许引入白名单内字符。
|
|||
|
|
|
|||
|
|
```go
|
|||
|
|
// bad
|
|||
|
|
func handler(w http.ResponseWriter, r *http.Request) {
|
|||
|
|
r.ParseForm()
|
|||
|
|
x := r.Form.Get("name")
|
|||
|
|
|
|||
|
|
var tmpl = `<!DOCTYPE html><html><body>
|
|||
|
|
<form action="/" method="post">
|
|||
|
|
First name:<br>
|
|||
|
|
<input type="text" name="name" value="">
|
|||
|
|
<input type="submit" value="Submit">
|
|||
|
|
</form><p>` + x + ` </p></body></html>`
|
|||
|
|
|
|||
|
|
t := template.New("main")
|
|||
|
|
t, _ = t.Parse(tmpl)
|
|||
|
|
t.Execute(w, "Hello")
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
// good
|
|||
|
|
import (
|
|||
|
|
"fmt"
|
|||
|
|
"github.com/go-playground/validator/v10"
|
|||
|
|
)
|
|||
|
|
|
|||
|
|
var validate *validator.Validate
|
|||
|
|
validate = validator.New()
|
|||
|
|
|
|||
|
|
func validateVariable(val) {
|
|||
|
|
errs := validate.Var(val, "gte=1,lte=100") // 限制必须是1-100的正整数
|
|||
|
|
if errs != nil {
|
|||
|
|
fmt.Println(errs)
|
|||
|
|
return false
|
|||
|
|
}
|
|||
|
|
return true
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
func handler(w http.ResponseWriter, r *http.Request) {
|
|||
|
|
r.ParseForm()
|
|||
|
|
x := r.Form.Get("name")
|
|||
|
|
|
|||
|
|
if validateVariable(x) {
|
|||
|
|
var tmpl = `<!DOCTYPE html><html><body>
|
|||
|
|
<form action="/" method="post">
|
|||
|
|
First name:<br>
|
|||
|
|
<input type="text" name="name" value="">
|
|||
|
|
<input type="submit" value="Submit">
|
|||
|
|
</form><p>` + x + ` </p></body></html>`
|
|||
|
|
t := template.New("main")
|
|||
|
|
t, _ = t.Parse(tmpl)
|
|||
|
|
t.Execute(w, "Hello")
|
|||
|
|
} else {
|
|||
|
|
// ...
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
```
|
|||
|
|
|
|||
|
|
### 1.5 Web跨域
|
|||
|
|
|
|||
|
|
#### 1.5.1 跨域资源共享CORS限制请求来源
|
|||
|
|
|
|||
|
|
- CORS请求保护不当可导致敏感信息泄漏，因此应当严格设置Access-Control-Allow-Origin使用同源策略进行保护。
|
|||
|
|
|
|||
|
|
```go
|
|||
|
|
// good
|
|||
|
|
c := cors.New(cors.Options{
|
|||
|
|
AllowedOrigins: []string{"http://qq.com", "https://qq.com"},
|
|||
|
|
AllowCredentials: true,
|
|||
|
|
Debug: false,
|
|||
|
|
})
|
|||
|
|
|
|||
|
|
// 引入中间件
|
|||
|
|
handler = c.Handler(handler)
|
|||
|
|
```
|
|||
|
|
|
|||
|
|
### 1.6 响应输出
|
|||
|
|
|
|||
|
|
#### 1.6.1 设置正确的HTTP响应包类型
|
|||
|
|
|
|||
|
|
- 响应头Content-Type与实际响应内容，应保持一致。如：API响应数据类型是json，则响应头使用`application/json`；若为xml，则设置为`text/xml`。
|
|||
|
|
|
|||
|
|
#### 1.6.2 添加安全响应头
|
|||
|
|
|
|||
|
|
- 所有接口、页面，添加响应头 `X-Content-Type-Options: nosniff`。
|
|||
|
|
- 所有接口、页面，添加响应头`X-Frame-Options`。按需合理设置其允许范围，包括：`DENY`、`SAMEORIGIN`、`ALLOW-FROM origin`。用法参考：[MDN文档](https://developer.mozilla.org/zh-CN/docs/Web/HTTP/X-Frame-Options)
|
|||
|
|
|
|||
|
|
#### 1.6.3 外部输入拼接到HTTP响应头中需进行过滤
|
|||
|
|
|
|||
|
|
- 应尽量避免外部可控参数拼接到HTTP响应头中，如业务需要则需要过滤掉`\r`、`\n`等换行符，或者拒绝携带换行符号的外部输入。
|
|||
|
|
|
|||
|
|
#### 1.6.4 外部输入拼接到response页面前进行编码处理
|
|||
|
|
|
|||
|
|
- 直出html页面或使用模板生成html页面的，推荐使用`text/template`自动编码，或者使用`html.EscapeString`或`text/template`对`<, >, &, ',"`等字符进行编码。
|
|||
|
|
|
|||
|
|
```go
|
|||
|
|
import (
|
|||
|
|
"html/template"
|
|||
|
|
)
|
|||
|
|
|
|||
|
|
func outtemplate(w http.ResponseWriter, r *http.Request) {
|
|||
|
|
param1 := r.URL.Query().Get("param1")
|
|||
|
|
tmpl := template.New("hello")
|
|||
|
|
tmpl, _ = tmpl.Parse(`{{define "T"}}{{.}}{{end}}`)
|
|||
|
|
tmpl.ExecuteTemplate(w, "T", param1)
|
|||
|
|
}
|
|||
|
|
```
|
|||
|
|
|
|||
|
|
### 1.7 会话管理
|
|||
|
|
|
|||
|
|
#### 1.7.1 安全维护session信息
|
|||
|
|
|
|||
|
|
- 用户登录时应重新生成session，退出登录后应清理session。
|
|||
|
|
|
|||
|
|
```go
|
|||
|
|
import (
|
|||
|
|
"github.com/gorilla/handlers"
|
|||
|
|
"github.com/gorilla/mux"
|
|||
|
|
"net/http"
|
|||
|
|
)
|
|||
|
|
|
|||
|
|
// 创建cookie
|
|||
|
|
func setToken(res http.ResponseWriter, req *http.Request) {
|
|||
|
|
expireToken := time.Now().Add(time.Minute * 30).Unix()
|
|||
|
|
expireCookie := time.Now().Add(time.Minute * 30)
|
|||
|
|
|
|||
|
|
//...
|
|||
|
|
|
|||
|
|
cookie := http.Cookie{
|
|||
|
|
Name: "Auth",
|
|||
|
|
Value: signedToken,
|
|||
|
|
Expires: expireCookie, // 过期失效
|
|||
|
|
HttpOnly: true,
|
|||
|
|
Path: "/",
|
|||
|
|
Domain: "127.0.0.1",
|
|||
|
|
Secure: true,
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
http.SetCookie(res, &cookie)
|
|||
|
|
http.Redirect(res, req, "/profile", 307)
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
// 删除cookie
|
|||
|
|
func logout(res http.ResponseWriter, req *http.Request) {
|
|||
|
|
deleteCookie := http.Cookie{
|
|||
|
|
Name: "Auth",
|
|||
|
|
Value: "none",
|
|||
|
|
Expires: time.Now(),
|
|||
|
|
}
|
|||
|
|
http.SetCookie(res, &deleteCookie)
|
|||
|
|
return
|
|||
|
|
}
|
|||
|
|
```
|
|||
|
|
|
|||
|
|
#### 1.7.2 CSRF防护
|
|||
|
|
|
|||
|
|
- 涉及系统敏感操作或可读取敏感信息的接口应校验`Referer`或添加`csrf_token`。
|
|||
|
|
|
|||
|
|
```go
|
|||
|
|
// good
|
|||
|
|
import (
|
|||
|
|
"github.com/gorilla/csrf"
|
|||
|
|
"github.com/gorilla/mux"
|
|||
|
|
"net/http"
|
|||
|
|
)
|
|||
|
|
|
|||
|
|
func main() {
|
|||
|
|
r := mux.NewRouter()
|
|||
|
|
r.HandleFunc("/signup", ShowSignupForm)
|
|||
|
|
r.HandleFunc("/signup/post", SubmitSignupForm)
|
|||
|
|
// 使用csrf_token验证
|
|||
|
|
http.ListenAndServe(":8000",
|
|||
|
|
csrf.Protect([]byte("32-byte-long-auth-key"))(r))
|
|||
|
|
}
|
|||
|
|
```
|
|||
|
|
|
|||
|
|
### 1.8 访问控制
|
|||
|
|
|
|||
|
|
#### 1.8.1 默认鉴权
|
|||
|
|
|
|||
|
|
- 除非资源完全可对外开放，否则系统默认进行身份认证，使用白名单的方式放开不需要认证的接口或页面。
|
|||
|
|
|
|||
|
|
- 根据资源的机密程度和用户角色，以最小权限原则，设置不同级别的权限，如完全公开、登录可读、登录可写、特定用户可读、特定用户可写等
|
|||
|
|
|
|||
|
|
- 涉及用户自身相关的数据的读写必须验证登录态用户身份及其权限，避免越权操作
|
|||
|
|
|
|||
|
|
```sql
|
|||
|
|
-- 伪代码
|
|||
|
|
select id from table where id=:id and userid=session.userid
|
|||
|
|
```
|
|||
|
|
|
|||
|
|
- 没有独立账号体系的外网服务使用`QQ`或`微信`登录，内网服务使用`统一登录服务`登录，其他使用账号密码登录的服务需要增加验证码等二次验证
|
|||
|
|
|
|||
|
|
### 1.9 并发保护
|
|||
|
|
|
|||
|
|
#### 1.9.1 禁止在闭包中直接调用循环变量
|
|||
|
|
|
|||
|
|
- 在循环中启动协程，当协程中使用到了循环的索引值，由于多个协程同时使用同一个变量会产生数据竞争，造成执行结果异常。
|
|||
|
|
|
|||
|
|
```go
|
|||
|
|
// bad
|
|||
|
|
func main() {
|
|||
|
|
runtime.GOMAXPROCS(runtime.NumCPU())
|
|||
|
|
var group sync.WaitGroup
|
|||
|
|
|
|||
|
|
for i := 0; i < 5; i++ {
|
|||
|
|
group.Add(1)
|
|||
|
|
go func() {
|
|||
|
|
defer group.Done()
|
|||
|
|
fmt.Printf("%-2d", i) // 这里打印的i不是所期望的
|
|||
|
|
}()
|
|||
|
|
}
|
|||
|
|
group.Wait()
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
// good
|
|||
|
|
func main() {
|
|||
|
|
runtime.GOMAXPROCS(runtime.NumCPU())
|
|||
|
|
var group sync.WaitGroup
|
|||
|
|
|
|||
|
|
for i := 0; i < 5; i++ {
|
|||
|
|
group.Add(1)
|
|||
|
|
go func(j int) {
|
|||
|
|
defer func() {
|
|||
|
|
if r := recover(); r != nil {
|
|||
|
|
fmt.Println("Recovered in start()")
|
|||
|
|
}
|
|||
|
|
group.Done()
|
|||
|
|
}()
|
|||
|
|
fmt.Printf("%-2d", j) // 闭包内部使用局部变量
|
|||
|
|
}(i) // 把循环变量显式地传给协程
|
|||
|
|
}
|
|||
|
|
group.Wait()
|
|||
|
|
}
|
|||
|
|
```
|
|||
|
|
|
|||
|
|
#### 1.9.2 禁止并发写map
|
|||
|
|
|
|||
|
|
- 并发写map容易造成程序崩溃并异常退出，建议加锁保护
|
|||
|
|
|
|||
|
|
```go
|
|||
|
|
// bad
|
|||
|
|
func main() {
|
|||
|
|
m := make(map[int]int)
|
|||
|
|
// 并发读写
|
|||
|
|
go func() {
|
|||
|
|
for {
|
|||
|
|
_ = m[1]
|
|||
|
|
}
|
|||
|
|
}()
|
|||
|
|
go func() {
|
|||
|
|
for {
|
|||
|
|
m[2] = 1
|
|||
|
|
}
|
|||
|
|
}()
|
|||
|
|
select {}
|
|||
|
|
}
|
|||
|
|
```
|
|||
|
|
|
|||
|
|
#### 1.9.3 确保并发安全
|
|||
|
|
|
|||
|
|
敏感操作如果未作并发安全限制，可导致数据读写异常，造成业务逻辑限制被绕过。可通过同步锁或者原子操作进行防护。
|
|||
|
|
|
|||
|
|
通过同步锁共享内存
|
|||
|
|
|
|||
|
|
```go
|
|||
|
|
// good
|
|||
|
|
var count int
|
|||
|
|
|
|||
|
|
func Count(lock *sync.Mutex) {
|
|||
|
|
lock.Lock() // 加写锁
|
|||
|
|
count++
|
|||
|
|
fmt.Println(count)
|
|||
|
|
lock.Unlock() // 解写锁，任何一个Lock()或RLock()均需要保证对应有Unlock()或RUnlock()
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
func main() {
|
|||
|
|
lock := &sync.Mutex{}
|
|||
|
|
for i := 0; i < 10; i++ {
|
|||
|
|
go Count(lock) // 传递指针是为了防止函数内的锁和调用锁不一致
|
|||
|
|
}
|
|||
|
|
for {
|
|||
|
|
lock.Lock()
|
|||
|
|
c := count
|
|||
|
|
lock.Unlock()
|
|||
|
|
runtime.Gosched() // 交出时间片给协程
|
|||
|
|
if c > 10 {
|
|||
|
|
break
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
```
|
|||
|
|
|
|||
|
|
- 使用`sync/atomic`执行原子操作
|
|||
|
|
|
|||
|
|
```go
|
|||
|
|
// good
|
|||
|
|
import (
|
|||
|
|
"sync"
|
|||
|
|
"sync/atomic"
|
|||
|
|
)
|
|||
|
|
|
|||
|
|
func main() {
|
|||
|
|
type Map map[string]string
|
|||
|
|
var m atomic.Value
|
|||
|
|
m.Store(make(Map))
|
|||
|
|
var mu sync.Mutex // used only by writers
|
|||
|
|
read := func(key string) (val string) {
|
|||
|
|
m1 := m.Load().(Map)
|
|||
|
|
return m1[key]
|
|||
|
|
}
|
|||
|
|
insert := func(key, val string) {
|
|||
|
|
mu.Lock() // 与潜在写入同步
|
|||
|
|
defer mu.Unlock()
|
|||
|
|
m1 := m.Load().(Map) // 导入struct当前数据
|
|||
|
|
m2 := make(Map) // 创建新值
|
|||
|
|
for k, v := range m1 {
|
|||
|
|
m2[k] = v
|
|||
|
|
}
|
|||
|
|
m2[key] = val
|
|||
|
|
m.Store(m2) // 用新的替代当前对象
|
|||
|
|
}
|
|||
|
|
_, _ = read, insert
|
|||
|
|
}
|
|||
|
|
```
|