From b418e14bd975bca7d8afd8a236a909c8405a29f6 Mon Sep 17 00:00:00 2001
From: Marcus Efraimsson <marcus.efraimsson@gmail.com>
Date: Fri, 15 Jun 2018 13:40:42 +0200
Subject: [PATCH] make sure to use real ip when validating white listed ip's

---
 pkg/middleware/auth_proxy.go      | 20 ++++++-----
 pkg/middleware/middleware_test.go | 55 +++++++++++++++++++++++++++++++
 2 files changed, 67 insertions(+), 8 deletions(-)

diff --git a/pkg/middleware/auth_proxy.go b/pkg/middleware/auth_proxy.go
index 144a0ae3a69..eff532b0da2 100644
--- a/pkg/middleware/auth_proxy.go
+++ b/pkg/middleware/auth_proxy.go
@@ -2,7 +2,6 @@ package middleware
 
 import (
 	"fmt"
-	"net"
 	"net/mail"
 	"reflect"
 	"strings"
@@ -29,7 +28,7 @@ func initContextWithAuthProxy(ctx *m.ReqContext, orgID int64) bool {
 	}
 
 	// if auth proxy ip(s) defined, check if request comes from one of those
-	if err := checkAuthenticationProxy(ctx.Req.RemoteAddr, proxyHeaderValue); err != nil {
+	if err := checkAuthenticationProxy(ctx.RemoteAddr(), proxyHeaderValue); err != nil {
 		ctx.Handle(407, "Proxy authentication required", err)
 		return true
 	}
@@ -197,18 +196,23 @@ func checkAuthenticationProxy(remoteAddr string, proxyHeaderValue string) error
 		return nil
 	}
 
-	proxies := strings.Split(setting.AuthProxyWhitelist, ",")
-	sourceIP, _, err := net.SplitHostPort(remoteAddr)
-	if err != nil {
-		return err
+	// Multiple ip addresses? Right-most IP address is the IP address of the most recent proxy
+	if strings.Contains(remoteAddr, ",") {
+		sourceIPs := strings.Split(remoteAddr, ",")
+		remoteAddr = strings.TrimSpace(sourceIPs[len(sourceIPs)-1])
 	}
 
+	remoteAddr = strings.TrimPrefix(remoteAddr, "[")
+	remoteAddr = strings.TrimSuffix(remoteAddr, "]")
+
+	proxies := strings.Split(setting.AuthProxyWhitelist, ",")
+
 	// Compare allowed IP addresses to actual address
 	for _, proxyIP := range proxies {
-		if sourceIP == strings.TrimSpace(proxyIP) {
+		if remoteAddr == strings.TrimSpace(proxyIP) {
 			return nil
 		}
 	}
 
-	return fmt.Errorf("Request for user (%s) from %s is not from the authentication proxy", proxyHeaderValue, sourceIP)
+	return fmt.Errorf("Request for user (%s) from %s is not from the authentication proxy", proxyHeaderValue, remoteAddr)
 }
diff --git a/pkg/middleware/middleware_test.go b/pkg/middleware/middleware_test.go
index b827751b1a5..0b50358ad73 100644
--- a/pkg/middleware/middleware_test.go
+++ b/pkg/middleware/middleware_test.go
@@ -293,6 +293,61 @@ func TestMiddlewareContext(t *testing.T) {
 			})
 		})
 
+		middlewareScenario("When auth_proxy is enabled and request has X-Forwarded-For that is not trusted", func(sc *scenarioContext) {
+			setting.AuthProxyEnabled = true
+			setting.AuthProxyHeaderName = "X-WEBAUTH-USER"
+			setting.AuthProxyHeaderProperty = "username"
+			setting.AuthProxyWhitelist = "192.168.1.1, 2001::23"
+
+			bus.AddHandler("test", func(query *m.GetSignedInUserQuery) error {
+				query.Result = &m.SignedInUser{OrgId: 4, UserId: 33}
+				return nil
+			})
+
+			bus.AddHandler("test", func(cmd *m.UpsertUserCommand) error {
+				cmd.Result = &m.User{Id: 33}
+				return nil
+			})
+
+			sc.fakeReq("GET", "/")
+			sc.req.Header.Add("X-WEBAUTH-USER", "torkelo")
+			sc.req.Header.Add("X-Forwarded-For", "client-ip, 192.168.1.1, 192.168.1.2")
+			sc.exec()
+
+			Convey("should return 407 status code", func() {
+				So(sc.resp.Code, ShouldEqual, 407)
+				So(sc.resp.Body.String(), ShouldContainSubstring, "Request for user (torkelo) from 192.168.1.2 is not from the authentication proxy")
+			})
+		})
+
+		middlewareScenario("When auth_proxy is enabled and request has X-Forwarded-For that is trusted", func(sc *scenarioContext) {
+			setting.AuthProxyEnabled = true
+			setting.AuthProxyHeaderName = "X-WEBAUTH-USER"
+			setting.AuthProxyHeaderProperty = "username"
+			setting.AuthProxyWhitelist = "192.168.1.1, 2001::23"
+
+			bus.AddHandler("test", func(query *m.GetSignedInUserQuery) error {
+				query.Result = &m.SignedInUser{OrgId: 4, UserId: 33}
+				return nil
+			})
+
+			bus.AddHandler("test", func(cmd *m.UpsertUserCommand) error {
+				cmd.Result = &m.User{Id: 33}
+				return nil
+			})
+
+			sc.fakeReq("GET", "/")
+			sc.req.Header.Add("X-WEBAUTH-USER", "torkelo")
+			sc.req.Header.Add("X-Forwarded-For", "client-ip, 192.168.1.2, 192.168.1.1")
+			sc.exec()
+
+			Convey("Should init context with user info", func() {
+				So(sc.context.IsSignedIn, ShouldBeTrue)
+				So(sc.context.UserId, ShouldEqual, 33)
+				So(sc.context.OrgId, ShouldEqual, 4)
+			})
+		})
+
 		middlewareScenario("When session exists for previous user, create a new session", func(sc *scenarioContext) {
 			setting.AuthProxyEnabled = true
 			setting.AuthProxyHeaderName = "X-WEBAUTH-USER"