secure

package module
v1.14.0 Latest Latest
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 Go to latest Published: Dec 27, 2023 License: MIT Imports: 8 Imported by: 688

README

Secure GoDoc Test

Secure is an HTTP middleware for Go that facilitates some quick security wins. It's a standard net/http Handler, and can be used with many frameworks or directly with Go's net/http package.

Usage

// main.go
package main

import (
    "net/http"

    "github.com/unrolled/secure"
)

var myHandler = http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
    w.Write([]byte("hello world"))
})

func main() {
    secureMiddleware := secure.New(secure.Options{
        AllowedHosts:          []string{"example\\.com", ".*\\.example\\.com"},
        AllowedHostsAreRegex:  true,
        HostsProxyHeaders:     []string{"X-Forwarded-Host"},
        SSLRedirect:           true,
        SSLHost:               "ssl.example.com",
        SSLProxyHeaders:       map[string]string{"X-Forwarded-Proto": "https"},
        STSSeconds:            31536000,
        STSIncludeSubdomains:  true,
        STSPreload:            true,
        FrameDeny:             true,
        ContentTypeNosniff:    true,
        BrowserXssFilter:      true,
        ContentSecurityPolicy: "script-src $NONCE",
    })

    app := secureMiddleware.Handler(myHandler)
    http.ListenAndServe("127.0.0.1:3000", app)
}

Be sure to include the Secure middleware as close to the top (beginning) as possible (but after logging and recovery). It's best to do the allowed hosts and SSL check before anything else.

The above example will only allow requests with a host name of 'example.com', or 'ssl.example.com'. Also if the request is not HTTPS, it will be redirected to HTTPS with the host name of 'ssl.example.com'. Once those requirements are satisfied, it will add the following headers:

Strict-Transport-Security: 31536000; includeSubdomains; preload
X-Frame-Options: DENY
X-Content-Type-Options: nosniff
X-XSS-Protection: 1; mode=block
Content-Security-Policy: script-src 'nonce-a2ZobGFoZg=='
Set the IsDevelopment option to true when developing!

When IsDevelopment is true, the AllowedHosts, SSLRedirect, and STS header will not be in effect. This allows you to work in development/test mode and not have any annoying redirects to HTTPS (ie. development can happen on HTTP), or block localhost has a bad host.

Available options

Secure comes with a variety of configuration options (Note: these are not the default option values. See the defaults below.):

// ...
s := secure.New(secure.Options{
    AllowedHosts: []string{"ssl.example.com"}, // AllowedHosts is a list of fully qualified domain names that are allowed. Default is empty list, which allows any and all host names.
    AllowedHostsAreRegex: false,  // AllowedHostsAreRegex determines, if the provided AllowedHosts slice contains valid regular expressions. Default is false.
    AllowRequestFunc: nil, // AllowRequestFunc is a custom function type that allows you to determine if the request should proceed or not based on your own custom logic. Default is nil.
    HostsProxyHeaders: []string{"X-Forwarded-Hosts"}, // HostsProxyHeaders is a set of header keys that may hold a proxied hostname value for the request.
    SSLRedirect: true, // If SSLRedirect is set to true, then only allow HTTPS requests. Default is false.
    SSLTemporaryRedirect: false, // If SSLTemporaryRedirect is true, the a 302 will be used while redirecting. Default is false (301).
    SSLHost: "ssl.example.com", // SSLHost is the host name that is used to redirect HTTP requests to HTTPS. Default is "", which indicates to use the same host.
    SSLHostFunc: nil, // SSLHostFunc is a function pointer, the return value of the function is the host name that has same functionality as `SSHost`. Default is nil. If SSLHostFunc is nil, the `SSLHost` option will be used.
    SSLProxyHeaders: map[string]string{"X-Forwarded-Proto": "https"}, // SSLProxyHeaders is set of header keys with associated values that would indicate a valid HTTPS request. Useful when using Nginx: `map[string]string{"X-Forwarded-Proto": "https"}`. Default is blank map.
    STSSeconds: 31536000, // STSSeconds is the max-age of the Strict-Transport-Security header. Default is 0, which would NOT include the header.
    STSIncludeSubdomains: true, // If STSIncludeSubdomains is set to true, the `includeSubdomains` will be appended to the Strict-Transport-Security header. Default is false.
    STSPreload: true, // If STSPreload is set to true, the `preload` flag will be appended to the Strict-Transport-Security header. Default is false.
    ForceSTSHeader: false, // STS header is only included when the connection is HTTPS. If you want to force it to always be added, set to true. `IsDevelopment` still overrides this. Default is false.
    FrameDeny: true, // If FrameDeny is set to true, adds the X-Frame-Options header with the value of `DENY`. Default is false.
    CustomFrameOptionsValue: "SAMEORIGIN", // CustomFrameOptionsValue allows the X-Frame-Options header value to be set with a custom value. This overrides the FrameDeny option. Default is "".
    ContentTypeNosniff: true, // If ContentTypeNosniff is true, adds the X-Content-Type-Options header with the value `nosniff`. Default is false.
    BrowserXssFilter: true, // If BrowserXssFilter is true, adds the X-XSS-Protection header with the value `1; mode=block`. Default is false.
    CustomBrowserXssValue: "1; report=https://example.com/xss-report", // CustomBrowserXssValue allows the X-XSS-Protection header value to be set with a custom value. This overrides the BrowserXssFilter option. Default is "".
    ContentSecurityPolicy: "default-src 'self'", // ContentSecurityPolicy allows the Content-Security-Policy header value to be set with a custom value. Default is "". Passing a template string will replace `$NONCE` with a dynamic nonce value of 16 bytes for each request which can be later retrieved using the Nonce function.
    ReferrerPolicy: "same-origin", // ReferrerPolicy allows the Referrer-Policy header with the value to be set with a custom value. Default is "".
    FeaturePolicy: "vibrate 'none';", // Deprecated: this header has been renamed to PermissionsPolicy. FeaturePolicy allows the Feature-Policy header with the value to be set with a custom value. Default is "".
    PermissionsPolicy: "fullscreen=(), geolocation=()", // PermissionsPolicy allows the Permissions-Policy header with the value to be set with a custom value. Default is "".
    CrossOriginOpenerPolicy: "same-origin", // CrossOriginOpenerPolicy allows the Cross-Origin-Opener-Policy header with the value to be set with a custom value. Default is "".

    IsDevelopment: true, // This will cause the AllowedHosts, SSLRedirect, and STSSeconds/STSIncludeSubdomains options to be ignored during development. When deploying to production, be sure to set this to false.
})
// ...
Default options

These are the preset options for Secure:

s := secure.New()

// Is the same as the default configuration options:

l := secure.New(secure.Options{
    AllowedHosts: []string,
    AllowedHostsAreRegex: false,
    AllowRequestFunc: nil,
    HostsProxyHeaders: []string,
    SSLRedirect: false,
    SSLTemporaryRedirect: false,
    SSLHost: "",
    SSLProxyHeaders: map[string]string{},
    STSSeconds: 0,
    STSIncludeSubdomains: false,
    STSPreload: false,
    ForceSTSHeader: false,
    FrameDeny: false,
    CustomFrameOptionsValue: "",
    ContentTypeNosniff: false,
    BrowserXssFilter: false,
    ContentSecurityPolicy: "",
    PublicKey: "",
    ReferrerPolicy: "",
    FeaturePolicy: "",
    PermissionsPolicy: "",
    CrossOriginOpenerPolicy: "",
    IsDevelopment: false,
})

The default bad host handler returns the following error:

http.Error(w, "Bad Host", http.StatusInternalServerError)

Call secure.SetBadHostHandler to set your own custom handler.

The default bad request handler returns the following error:

http.Error(w, "Bad Request", http.StatusBadRequest)

Call secure.SetBadRequestHandler to set your own custom handler.

Allow Request Function

Secure allows you to set a custom function (func(r *http.Request) bool) for the AllowRequestFunc option. You can use this function as a custom filter to allow the request to continue or simply reject it. This can be handy if you need to do any dynamic filtering on any of the request properties. It should be noted that this function will be called on every request, so be sure to make your checks quick and not relying on time consuming external calls (or you will be slowing down all requests). See above on how to set a custom handler for the rejected requests.

Redirecting HTTP to HTTPS

If you want to redirect all HTTP requests to HTTPS, you can use the following example.

// main.go
package main

import (
    "log"
    "net/http"

    "github.com/unrolled/secure"
)

var myHandler = http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
    w.Write([]byte("hello world"))
})

func main() {
    secureMiddleware := secure.New(secure.Options{
        SSLRedirect: true,
        SSLHost:     "localhost:8443", // This is optional in production. The default behavior is to just redirect the request to the HTTPS protocol. Example: http://github.com/some_page would be redirected to https://github.com/some_page.
    })

    app := secureMiddleware.Handler(myHandler)

    // HTTP
    go func() {
        log.Fatal(http.ListenAndServe(":8080", app))
    }()

    // HTTPS
    // To generate a development cert and key, run the following from your *nix terminal:
    // go run $GOROOT/src/crypto/tls/generate_cert.go --host="localhost"
    log.Fatal(http.ListenAndServeTLS(":8443", "cert.pem", "key.pem", app))
}
Strict Transport Security

The STS header will only be sent on verified HTTPS connections (and when IsDevelopment is false). Be sure to set the SSLProxyHeaders option if your application is behind a proxy to ensure the proper behavior. If you need the STS header for all HTTP and HTTPS requests (which you shouldn't), you can use the ForceSTSHeader option. Note that if IsDevelopment is true, it will still disable this header even when ForceSTSHeader is set to true.

  • The preload flag is required for domain inclusion in Chrome's preload list.
Content Security Policy

You can utilize the CSP Builder to create your policies:

import (
	"github.com/unrolled/secure"
	"github.com/unrolled/secure/cspbuilder"
)

cspBuilder := cspbuilder.Builder{
	Directives: map[string][]string{
		cspbuilder.DefaultSrc: {"self"},
		cspbuilder.ScriptSrc:  {"self", "www.google-analytics.com"},
		cspbuilder.ImgSrc:     {"*"},
	},
}

opt := secure.Options{
	ContentSecurityPolicy: cspBuilder.MustBuild(),
}

Integration examples

chi
// main.go
package main

import (
    "net/http"

    "github.com/pressly/chi"
    "github.com/unrolled/secure"
)

func main() {
    secureMiddleware := secure.New(secure.Options{
        FrameDeny: true,
    })

    r := chi.NewRouter()
    r.Use(secureMiddleware.Handler)

    r.Get("/", func(w http.ResponseWriter, r *http.Request) {
        w.Write([]byte("X-Frame-Options header is now `DENY`."))
    })

    http.ListenAndServe("127.0.0.1:3000", r)
}
Echo
// main.go
package main

import (
    "net/http"

    "github.com/labstack/echo"
    "github.com/unrolled/secure"
)

func main() {
    secureMiddleware := secure.New(secure.Options{
        FrameDeny: true,
    })

    e := echo.New()
    e.GET("/", func(c echo.Context) error {
        return c.String(http.StatusOK, "X-Frame-Options header is now `DENY`.")
    })

    e.Use(echo.WrapMiddleware(secureMiddleware.Handler))
    e.Logger.Fatal(e.Start("127.0.0.1:3000"))
}
Gin
// main.go
package main

import (
    "github.com/gin-gonic/gin"
    "github.com/unrolled/secure"
)

func main() {
    secureMiddleware := secure.New(secure.Options{
        FrameDeny: true,
    })
    secureFunc := func() gin.HandlerFunc {
        return func(c *gin.Context) {
            err := secureMiddleware.Process(c.Writer, c.Request)

            // If there was an error, do not continue.
            if err != nil {
                c.Abort()
                return
            }

            // Avoid header rewrite if response is a redirection.
            if status := c.Writer.Status(); status > 300 && status < 399 {
                c.Abort()
            }
        }
    }()

    router := gin.Default()
    router.Use(secureFunc)

    router.GET("/", func(c *gin.Context) {
        c.String(200, "X-Frame-Options header is now `DENY`.")
    })

    router.Run("127.0.0.1:3000")
}
Goji
// main.go
package main

import (
    "net/http"

    "github.com/unrolled/secure"
    "github.com/zenazn/goji"
    "github.com/zenazn/goji/web"
)

func main() {
    secureMiddleware := secure.New(secure.Options{
        FrameDeny: true,
    })

    goji.Get("/", func(c web.C, w http.ResponseWriter, req *http.Request) {
        w.Write([]byte("X-Frame-Options header is now `DENY`."))
    })
    goji.Use(secureMiddleware.Handler)
    goji.Serve() // Defaults to ":8000".
}
Iris
//main.go
package main

import (
    "github.com/kataras/iris/v12"
    "github.com/unrolled/secure"
)

func main() {
    app := iris.New()

    secureMiddleware := secure.New(secure.Options{
        FrameDeny: true,
    })

    app.Use(iris.FromStd(secureMiddleware.HandlerFuncWithNext))
    // Identical to:
    // app.Use(func(ctx iris.Context) {
    //     err := secureMiddleware.Process(ctx.ResponseWriter(), ctx.Request())
    //
    //     // If there was an error, do not continue.
    //     if err != nil {
    //         return
    //     }
    //
    //     ctx.Next()
    // })

    app.Get("/home", func(ctx iris.Context) {
        ctx.Writef("X-Frame-Options header is now `%s`.", "DENY")
    })

    app.Listen(":8080")
}
Mux
//main.go
package main

import (
    "log"
    "net/http"

    "github.com/gorilla/mux"
    "github.com/unrolled/secure"
)

func main() {
    secureMiddleware := secure.New(secure.Options{
        FrameDeny: true,
    })

    r := mux.NewRouter()
    r.Use(secureMiddleware.Handler)
    http.Handle("/", r)
    log.Fatal(http.ListenAndServe(fmt.Sprintf(":%d", 8080), nil))
}
Negroni

Note this implementation has a special helper function called HandlerFuncWithNext.

// main.go
package main

import (
    "net/http"

    "github.com/urfave/negroni"
    "github.com/unrolled/secure"
)

func main() {
    mux := http.NewServeMux()
    mux.HandleFunc("/", func(w http.ResponseWriter, req *http.Request) {
        w.Write([]byte("X-Frame-Options header is now `DENY`."))
    })

    secureMiddleware := secure.New(secure.Options{
        FrameDeny: true,
    })

    n := negroni.Classic()
    n.Use(negroni.HandlerFunc(secureMiddleware.HandlerFuncWithNext))
    n.UseHandler(mux)

    n.Run("127.0.0.1:3000")
}

Documentation

Overview

Package secure is an HTTP middleware for Go that facilitates some quick security wins. 

package main

import (
    "net/http"

    "github.com/unrolled/secure"
)

var myHandler = http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
    w.Write([]byte("hello world"))
})

func main() {
    secureMiddleware := secure.New(secure.Options{
        AllowedHosts: []string{"www.example.com", "sub.example.com"},
        SSLRedirect:  true,
    })

    app := secureMiddleware.Handler(myHandler)
    http.ListenAndServe("127.0.0.1:3000", app)
}

Index

Constants

This section is empty.

Variables

This section is empty.

Functions

func CSPNonce 

func CSPNonce(c context.Context) string

CSPNonce returns the nonce value associated with the present request. If no nonce has been generated it returns an empty string.

func WithCSPNonce 

func WithCSPNonce(ctx context.Context, nonce string) context.Context

WithCSPNonce returns a context derived from ctx containing the given nonce as a value.

This is intended for testing or more advanced use-cases; For ordinary HTTP handlers, clients can rely on this package's middleware to populate the CSP nonce in the context.

Types

type AllowRequestFunc added in v1.12.0 

type AllowRequestFunc func(r *http.Request) bool

AllowRequestFunc is a custom function type that can be used to dynamically determine if a request should proceed or not.

type Options 

type Options struct {
	// If BrowserXssFilter is true, adds the X-XSS-Protection header with the value `1; mode=block`. Default is false.
	BrowserXssFilter bool //nolint:stylecheck,revive
	// If ContentTypeNosniff is true, adds the X-Content-Type-Options header with the value `nosniff`. Default is false.
	ContentTypeNosniff bool
	// If ForceSTSHeader is set to true, the STS header will be added even when the connection is HTTP. Default is false.
	ForceSTSHeader bool
	// If FrameDeny is set to true, adds the X-Frame-Options header with the value of `DENY`. Default is false.
	FrameDeny bool
	// When developing, the AllowedHosts, SSL, and STS options can cause some unwanted effects. Usually testing happens on http, not https, and on localhost, not your production domain... so set this to true for dev environment.
	// If you would like your development environment to mimic production with complete Host blocking, SSL redirects, and STS headers, leave this as false. Default if false.
	IsDevelopment bool

	// If SSLRedirect is set to true, then only allow https requests. Default is false.
	SSLRedirect bool
	// If SSLForceHost is true and SSLHost is set, requests will be forced to use SSLHost even the ones that are already using SSL. Default is false.
	SSLForceHost bool
	// If SSLTemporaryRedirect is true, the a 302 will be used while redirecting. Default is false (301).
	SSLTemporaryRedirect bool
	// If STSIncludeSubdomains is set to true, the `includeSubdomains` will be appended to the Strict-Transport-Security header. Default is false.
	STSIncludeSubdomains bool
	// If STSPreload is set to true, the `preload` flag will be appended to the Strict-Transport-Security header. Default is false.
	STSPreload bool
	// ContentSecurityPolicy allows the Content-Security-Policy header value to be set with a custom value. Default is "".
	ContentSecurityPolicy string
	// ContentSecurityPolicyReportOnly allows the Content-Security-Policy-Report-Only header value to be set with a custom value. Default is "".
	ContentSecurityPolicyReportOnly string
	// CustomBrowserXssValue allows the X-XSS-Protection header value to be set with a custom value. This overrides the BrowserXssFilter option. Default is "".
	CustomBrowserXssValue string //nolint:stylecheck,revive
	// Passing a template string will replace `$NONCE` with a dynamic nonce value of 16 bytes for each request which can be later retrieved using the Nonce function.
	// Eg: script-src $NONCE -> script-src 'nonce-a2ZobGFoZg=='
	// CustomFrameOptionsValue allows the X-Frame-Options header value to be set with a custom value. This overrides the FrameDeny option. Default is "".
	CustomFrameOptionsValue string
	// ReferrerPolicy allows sites to control when browsers will pass the Referer header to other sites. Default is "".
	ReferrerPolicy string
	// FeaturePolicy allows to selectively enable and disable use of various browser features and APIs. Default is "".
	// Deprecated: This header has been renamed to Permissions-Policy.
	FeaturePolicy string
	// PermissionsPolicy allows to selectively enable and disable use of various browser features and APIs. Default is "".
	PermissionsPolicy string
	// CrossOriginOpenerPolicy allows you to ensure a top-level document does not share a browsing context group with cross-origin documents. Default is "".
	// Reference: https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Cross-Origin-Opener-Policy
	CrossOriginOpenerPolicy string
	// SSLHost is the host name that is used to redirect http requests to https. Default is "", which indicates to use the same host.
	SSLHost string
	// AllowedHosts is a slice of fully qualified domain names that are allowed. Default is an empty slice, which allows any and all host names.
	AllowedHosts []string
	// AllowedHostsAreRegex determines, if the provided `AllowedHosts` slice contains valid regular expressions. If this flag is set to true, every request's host will be checked against these expressions. Default is false.
	AllowedHostsAreRegex bool
	// AllowRequestFunc is a custom function that allows you to determine if the request should proceed or not based on your own custom logic. Default is nil.
	AllowRequestFunc AllowRequestFunc
	// HostsProxyHeaders is a set of header keys that may hold a proxied hostname value for the request.
	HostsProxyHeaders []string
	// SSLHostFunc is a function pointer, the return value of the function is the host name that has same functionality as `SSHost`. Default is nil.
	// If SSLHostFunc is nil, the `SSLHost` option will be used.
	SSLHostFunc *SSLHostFunc
	// SSLProxyHeaders is set of header keys with associated values that would indicate a valid https request. Useful when using Nginx: `map[string]string{"X-Forwarded-Proto": "https"}`. Default is blank map.
	SSLProxyHeaders map[string]string
	// STSSeconds is the max-age of the Strict-Transport-Security header. Default is 0, which would NOT include the header.
	STSSeconds int64
	// SecureContextKey allows a custom key to be specified for context storage.
	SecureContextKey string
	// contains filtered or unexported fields
}

Options is a struct for specifying configuration options for the secure.Secure middleware.

type SSLHostFunc 

type SSLHostFunc func(host string) (newHost string)

SSLHostFunc is a custom function type that can be used to dynamically set the SSL host of a request.

type Secure 

type Secure struct {
	// contains filtered or unexported fields
}

Secure is a middleware that helps setup a few basic security features. A single secure.Options struct can be provided to configure which features should be enabled, and the ability to override a few of the default values.

func New 

func New(options ...Options) *Secure

New constructs a new Secure instance with the supplied options.

func (*Secure) Handler 

func (s *Secure) Handler(h http.Handler) http.Handler

Handler implements the http.HandlerFunc for integration with the standard net/http lib.

func (*Secure) HandlerForRequestOnly 

func (s *Secure) HandlerForRequestOnly(h http.Handler) http.Handler

HandlerForRequestOnly implements the http.HandlerFunc for integration with the standard net/http lib. Note that this is for requests only and will not write any headers.

func (*Secure) HandlerFuncWithNext 

func (s *Secure) HandlerFuncWithNext(w http.ResponseWriter, r *http.Request, next http.HandlerFunc)

HandlerFuncWithNext is a special implementation for Negroni, but could be used elsewhere.

func (*Secure) HandlerFuncWithNextForRequestOnly 

func (s *Secure) HandlerFuncWithNextForRequestOnly(w http.ResponseWriter, r *http.Request, next http.HandlerFunc)

HandlerFuncWithNextForRequestOnly is a special implementation for Negroni, but could be used elsewhere. Note that this is for requests only and will not write any headers.

func (*Secure) ModifyResponseHeaders 

func (s *Secure) ModifyResponseHeaders(res *http.Response) error

ModifyResponseHeaders modifies the Response. Used by http.ReverseProxy.

func (*Secure) Process 

func (s *Secure) Process(w http.ResponseWriter, r *http.Request) error

Process runs the actual checks and writes the headers in the ResponseWriter.

func (*Secure) ProcessAndReturnNonce added in v1.0.2 

func (s *Secure) ProcessAndReturnNonce(w http.ResponseWriter, r *http.Request) (string, error)

ProcessAndReturnNonce runs the actual checks and writes the headers in the ResponseWriter. In addition, the generated nonce for the request is returned as well as the error value.

func (*Secure) ProcessNoModifyRequest 

func (s *Secure) ProcessNoModifyRequest(w http.ResponseWriter, r *http.Request) (http.Header, *http.Request, error)

ProcessNoModifyRequest runs the actual checks but does not write the headers in the ResponseWriter.

func (*Secure) SetBadHostHandler 

func (s *Secure) SetBadHostHandler(handler http.Handler)

SetBadHostHandler sets the handler to call when secure rejects the host name.

func (*Secure) SetBadRequestHandler added in v1.12.0 

func (s *Secure) SetBadRequestHandler(handler http.Handler)

SetBadRequestHandler sets the handler to call when the AllowRequestFunc rejects a request.

Source Files

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