use github.com/goji/httpauth instead

vendor/github.com/goji/httpauth/basic_auth.go

@@ -0,0 +1,185 @@
+package httpauth
+
+import (
+	"bytes"
+	"crypto/sha256"
+	"crypto/subtle"
+	"encoding/base64"
+	"fmt"
+	"net/http"
+	"strings"
+)
+
+type basicAuth struct {
+	h    http.Handler
+	opts AuthOptions
+}
+
+// AuthOptions stores the configuration for HTTP Basic Authentication.
+//
+// A http.Handler may also be passed to UnauthorizedHandler to override the
+// default error handler if you wish to serve a custom template/response.
+type AuthOptions struct {
+	Realm               string
+	User                string
+	Password            string
+	AuthFunc            func(string, string, *http.Request) bool
+	UnauthorizedHandler http.Handler
+}
+
+// Satisfies the http.Handler interface for basicAuth.
+func (b basicAuth) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	// Check if we have a user-provided error handler, else set a default
+	if b.opts.UnauthorizedHandler == nil {
+		b.opts.UnauthorizedHandler = http.HandlerFunc(defaultUnauthorizedHandler)
+	}
+
+	// Check that the provided details match
+	if b.authenticate(r) == false {
+		b.requestAuth(w, r)
+		return
+	}
+
+	// Call the next handler on success.
+	b.h.ServeHTTP(w, r)
+}
+
+// authenticate retrieves and then validates the user:password combination provided in
+// the request header. Returns 'false' if the user has not successfully authenticated.
+func (b *basicAuth) authenticate(r *http.Request) bool {
+	const basicScheme string = "Basic "
+
+	if r == nil {
+		return false
+	}
+
+	// In simple mode, prevent authentication with empty credentials if User is
+	// not set. Allow empty passwords to support non-password use-cases.
+	if b.opts.AuthFunc == nil && b.opts.User == "" {
+		return false
+	}
+
+	// Confirm the request is sending Basic Authentication credentials.
+	auth := r.Header.Get("Authorization")
+	if !strings.HasPrefix(auth, basicScheme) {
+		return false
+	}
+
+	// Get the plain-text username and password from the request.
+	// The first six characters are skipped - e.g. "Basic ".
+	str, err := base64.StdEncoding.DecodeString(auth[len(basicScheme):])
+	if err != nil {
+		return false
+	}
+
+	// Split on the first ":" character only, with any subsequent colons assumed to be part
+	// of the password. Note that the RFC2617 standard does not place any limitations on
+	// allowable characters in the password.
+	creds := bytes.SplitN(str, []byte(":"), 2)
+
+	if len(creds) != 2 {
+		return false
+	}
+
+	givenUser := string(creds[0])
+	givenPass := string(creds[1])
+
+	// Default to Simple mode if no AuthFunc is defined.
+	if b.opts.AuthFunc == nil {
+		b.opts.AuthFunc = b.simpleBasicAuthFunc
+	}
+
+	return b.opts.AuthFunc(givenUser, givenPass, r)
+}
+
+// simpleBasicAuthFunc authenticates the supplied username and password against
+// the User and Password set in the Options struct.
+func (b *basicAuth) simpleBasicAuthFunc(user, pass string, r *http.Request) bool {
+	// Equalize lengths of supplied and required credentials
+	// by hashing them
+	givenUser := sha256.Sum256([]byte(user))
+	givenPass := sha256.Sum256([]byte(pass))
+	requiredUser := sha256.Sum256([]byte(b.opts.User))
+	requiredPass := sha256.Sum256([]byte(b.opts.Password))
+
+	// Compare the supplied credentials to those set in our options
+	if subtle.ConstantTimeCompare(givenUser[:], requiredUser[:]) == 1 &&
+		subtle.ConstantTimeCompare(givenPass[:], requiredPass[:]) == 1 {
+		return true
+	}
+
+	return false
+}
+
+// Require authentication, and serve our error handler otherwise.
+func (b *basicAuth) requestAuth(w http.ResponseWriter, r *http.Request) {
+	w.Header().Set("WWW-Authenticate", fmt.Sprintf(`Basic realm=%q`, b.opts.Realm))
+	b.opts.UnauthorizedHandler.ServeHTTP(w, r)
+}
+
+// defaultUnauthorizedHandler provides a default HTTP 401 Unauthorized response.
+func defaultUnauthorizedHandler(w http.ResponseWriter, r *http.Request) {
+	http.Error(w, http.StatusText(http.StatusUnauthorized), http.StatusUnauthorized)
+}
+
+// BasicAuth provides HTTP middleware for protecting URIs with HTTP Basic Authentication
+// as per RFC 2617. The server authenticates a user:password combination provided in the
+// "Authorization" HTTP header.
+//
+// Example:
+//
+//     package main
+//
+//     import(
+//            "net/http"
+//            "github.com/zenazn/goji"
+//            "github.com/goji/httpauth"
+//     )
+//
+//     func main() {
+//          basicOpts := httpauth.AuthOptions{
+//                      Realm: "Restricted",
+//                      User: "Dave",
+//                      Password: "ClearText",
+//                  }
+//
+//          goji.Use(httpauth.BasicAuth(basicOpts), SomeOtherMiddleware)
+//          goji.Get("/thing", myHandler)
+//  }
+//
+// Note: HTTP Basic Authentication credentials are sent in plain text, and therefore it does
+// not make for a wholly secure authentication mechanism. You should serve your content over
+// HTTPS to mitigate this, noting that "Basic Authentication" is meant to be just that: basic!
+func BasicAuth(o AuthOptions) func(http.Handler) http.Handler {
+	fn := func(h http.Handler) http.Handler {
+		return basicAuth{h, o}
+	}
+	return fn
+}
+
+// SimpleBasicAuth is a convenience wrapper around BasicAuth. It takes a user and password, and
+// returns a pre-configured BasicAuth handler using the "Restricted" realm and a default 401 handler.
+//
+// Example:
+//
+//     package main
+//
+//     import(
+//            "net/http"
+//            "github.com/zenazn/goji/web/httpauth"
+//     )
+//
+//     func main() {
+//
+//          goji.Use(httpauth.SimpleBasicAuth("dave", "somepassword"), SomeOtherMiddleware)
+//          goji.Get("/thing", myHandler)
+//      }
+//
+func SimpleBasicAuth(user, password string) func(http.Handler) http.Handler {
+	opts := AuthOptions{
+		Realm:    "Restricted",
+		User:     user,
+		Password: password,
+	}
+	return BasicAuth(opts)
+}