CSRF

Cross-site request forgery(CSRF)是一种挟制用户在当前已登录的Web应用程序上执行非本意的操作的攻击方法。

Hertz 提供了 CSRF 中间件,可帮助您防止跨站点请求伪造攻击。

安装

go get github.com/hertz-contrib/csrf

示例代码

package main

import (
	"context"

	"github.com/cloudwego/hertz/pkg/app"
	"github.com/cloudwego/hertz/pkg/app/server"
	"github.com/hertz-contrib/csrf"
	"github.com/hertz-contrib/sessions"
	"github.com/hertz-contrib/sessions/cookie"
)

func main() {
	h := server.Default()

	store := cookie.NewStore([]byte("secret"))
	h.Use(sessions.New("csrf-session", store))
	h.Use(csrf.New())

	h.GET("/protected", func(c context.Context, ctx *app.RequestContext) {
		ctx.String(200, csrf.GetToken(ctx))
	})

	h.POST("/protected", func(c context.Context, ctx *app.RequestContext) {
		ctx.String(200, "CSRF token is valid")
	})

	h.Spin()
}

配置

配置项默认值介绍
SecretcsrfSecret用于生成令牌(必要配置)
IgnoreMethods“GET”, “HEAD”, “OPTIONS”, “TRACE”被忽略的方法将将视为无需 csrf保护
NextnilNext 定义了一个函数,当返回真时,跳过这个 csrf 中间件。
KeyLookupheader:X-CSRF-TOKENKeyLookup 是一个"“形式的字符串,用于创建一个从请求中提取令牌的 Extractor。
ErrorFuncfunc(ctx context.Context, c *app.RequestContext) { panic(c.Errors.Last()) }app.HandlerFunc返回一个错误时,ErrorFunc 被执行
Extractor基于 KeyLookup 创建Extractor返回csrf token。如果设置了这个,它将被用来代替基于KeyLookupExtractor

WithSecret

csrf 中间件提供了 WithSecret 用于帮助用户设置自定义秘钥用于签发 token ,默认为 csrfSecret

函数签名:

func WithSecret(secret string) Option

默认值:csrfSecret

示例代码:

package main

import (
	"context"

	"github.com/cloudwego/hertz/pkg/app"
	"github.com/cloudwego/hertz/pkg/app/server"
	"github.com/hertz-contrib/csrf"
	"github.com/hertz-contrib/sessions"
	"github.com/hertz-contrib/sessions/cookie"
)

func main() {
	h := server.Default()

	store := cookie.NewStore([]byte("store"))
	h.Use(sessions.New("csrf-session", store))
	h.Use(csrf.New(csrf.WithSecret("your_secret")))

	h.GET("/protected", func(c context.Context, ctx *app.RequestContext) {
		ctx.String(200, csrf.GetToken(ctx))
	})
	h.POST("/protected", func(c context.Context, ctx *app.RequestContext) {
		ctx.String(200, "CSRF token is valid")
	})

	h.Spin()
}

WithIgnoredMethods

csrf 中间件提供了 WithIgnoredMethods 用于帮助用户设置自定义无需保护的方法,默认为 GET, HEAD, OPTIONSTRACE

函数签名:

func WithIgnoredMethods(methods []string) Option 

默认值:{"GET", "HEAD", "OPTIONS", "TRACE"}

示例代码:

package main

import (
	"context"

	"github.com/cloudwego/hertz/pkg/app"
	"github.com/cloudwego/hertz/pkg/app/server"
	"github.com/hertz-contrib/csrf"
	"github.com/hertz-contrib/sessions"
	"github.com/hertz-contrib/sessions/cookie"
)

func main() {
	h := server.Default()

	store := cookie.NewStore([]byte("secret"))
    h.Use(sessions.New("csrf-session", store))
	h.Use(csrf.New(csrf.WithIgnoredMethods([]string{"GET", "HEAD", "TRACE"})))

	h.GET("/protected", func(c context.Context, ctx *app.RequestContext) {
		ctx.String(200, csrf.GetToken(ctx))
	})

	h.OPTIONS("/protected", func(c context.Context, ctx *app.RequestContext) {
		ctx.String(200, "success")
	})
	h.Spin()
}

WithErrorFunc

csrf 中间件提供了 WithErrorFunc 方便用户自定义错误处理逻辑。

函数签名:

func WithErrorFunc(f app.HandlerFunc) Option

默认实现:

func(ctx context.Context, c *app.RequestContext) { panic(c.Errors.Last()) }

示例代码:

package main

import (
	"context"
	"fmt"
	"net/http"

	"github.com/cloudwego/hertz/pkg/app"
	"github.com/cloudwego/hertz/pkg/app/server"
	"github.com/hertz-contrib/csrf"
	"github.com/hertz-contrib/sessions"
	"github.com/hertz-contrib/sessions/cookie"

)

func myErrFunc(c context.Context, ctx *app.RequestContext) {
    if ctx.Errors.Last() == nil {
        err := fmt.Errorf("myErrFunc called when no error occurs")
        ctx.String(400, err.Error())
        ctx.Abort()
    }
	ctx.AbortWithMsg(ctx.Errors.Last().Error(), http.StatusBadRequest)
}

func main() {
	h := server.Default()

	store := cookie.NewStore([]byte("store"))
	h.Use(sessions.New("csrf-session", store))
	h.Use(csrf.New(csrf.WithErrorFunc(myErrFunc)))

	h.GET("/protected", func(c context.Context, ctx *app.RequestContext) {
		ctx.String(200, csrf.GetToken(ctx))
	})
	h.POST("/protected", func(c context.Context, ctx *app.RequestContext) {
		ctx.String(200, "CSRF token is valid")
	})

	h.Spin()
}

WithKeyLookUp

csrf 中间件提供了 WithKeyLookUp 帮助用户设置 keyLookup

csrf 用于从 source(支持的 source 包括 headerparamqueryform) 中提取 token

格式为 <source>:<key>,默认值为:header:X-CSRF-TOKEN

函数签名:

func WithKeyLookUp(lookup string) Option

默认值: header:X-CSRF-TOKEN"

示例代码:

package main

import (
	"context"

	"github.com/cloudwego/hertz/pkg/app"
	"github.com/cloudwego/hertz/pkg/app/server"
	"github.com/hertz-contrib/csrf"
	"github.com/hertz-contrib/sessions"
	"github.com/hertz-contrib/sessions/cookie"
)

func main() {
	h := server.Default()

	store := cookie.NewStore([]byte("store"))
	h.Use(sessions.New("csrf-session", store))
	h.Use(csrf.New(csrf.WithKeyLookUp("form:csrf")))

	h.GET("/protected", func(c context.Context, ctx *app.RequestContext) {
		ctx.String(200, csrf.GetToken(ctx))
	})
	h.POST("/protected", func(c context.Context, ctx *app.RequestContext) {
		ctx.String(200, "CSRF token is valid")
	})

	h.Spin()
}

WithNext

csrf 中间件提供了 WithNext 方便用户自定义设置,以在特定条件下跳过 csrf中间件。

函数签名:

func WithNext(f CsrfNextHandler) Option

默认:nil

示例代码:

package main

import (
	"context"
	
	"github.com/cloudwego/hertz/pkg/app"
	"github.com/cloudwego/hertz/pkg/app/server"
	"github.com/hertz-contrib/csrf"
	"github.com/hertz-contrib/sessions"
	"github.com/hertz-contrib/sessions/cookie"
)

func isPostMethod(_ context.Context, ctx *app.RequestContext) bool {
	if string(ctx.Method()) == "POST" {
		return true
	} else {
		return false
	}
}

func main() {
	h := server.Default()

	store := cookie.NewStore([]byte("store"))
	h.Use(sessions.New("csrf-session", store))

	//  skip csrf middleware when request method is post
	h.Use(csrf.New(csrf.WithNext(isPostMethod)))

	h.POST("/protected", func(c context.Context, ctx *app.RequestContext) {
		ctx.String(200, "success even no csrf-token in header")
	})
	h.Spin()
}

WithExtractor

csrf 中间件提供了 WithExtractor,供用户通过自定义的方法从请求中获取csrf-token

函数签名:

func WithExtractor(f CsrfExtractorHandler) Option

默认实现:

func CsrfFromHeader(param string) func(ctx context.Context, c *app.RequestContext) (string, error) {
	return func(ctx context.Context, c *app.RequestContext) (string, error) {
		token := c.GetHeader(param)
		if string(token) == "" {
			return "", errMissingHeader
		}
		return string(token), nil
	}
}

示例代码:

package main

import (
	"context"
	"errors"
	
	"github.com/cloudwego/hertz/pkg/app"
	"github.com/cloudwego/hertz/pkg/app/server"
	"github.com/hertz-contrib/csrf"
	"github.com/hertz-contrib/sessions"
	"github.com/hertz-contrib/sessions/cookie"
)

func myExtractor(c context.Context, ctx *app.RequestContext) (string, error) {
	token := ctx.FormValue("csrf-token")
	if token == nil {
		return "", errors.New("missing token in form-data")
	}
	return string(token), nil
}

func main() {
	h := server.Default()

	store := cookie.NewStore([]byte("secret"))
	h.Use(sessions.New("csrf-session", store))
	h.Use(csrf.New(csrf.WithExtractor(myExtractor)))

	h.GET("/protected", func(c context.Context, ctx *app.RequestContext) {
		ctx.String(200, csrf.GetToken(ctx))
	})
	h.POST("/protected", func(c context.Context, ctx *app.RequestContext) {
		ctx.String(200, "CSRF token is valid")
	})

	h.Spin()
}