From 599514ad680a713b35226ac9aaddb971901c5e8e Mon Sep 17 00:00:00 2001
From: Kyle Brandt <kyle@grafana.com>
Date: Wed, 12 Jun 2019 13:15:50 +0200
Subject: [PATCH]  middleware: add security related HTTP(S) response headers
 (#17522)

  * x_xss_protection
  * strict_transport_security (HSTS)
  * x_content_type_options

these are currently defaulted to false (off) until the next minor release.

fixes #17509
---
 conf/defaults.ini                          | 25 +++++++++++++++++++
 conf/sample.ini                            | 24 ++++++++++++++++++
 docs/sources/installation/configuration.md | 24 ++++++++++++++++++
 pkg/middleware/middleware.go               | 26 +++++++++++++++++++
 pkg/setting/setting.go                     | 29 ++++++++++++++++------
 5 files changed, 120 insertions(+), 8 deletions(-)

diff --git a/conf/defaults.ini b/conf/defaults.ini
index 4b187d7e8be..af362157aea 100644
--- a/conf/defaults.ini
+++ b/conf/defaults.ini
@@ -182,6 +182,31 @@ cookie_samesite = lax
 # set to true if you want to allow browsers to render Grafana in a <frame>, <iframe>, <embed> or <object>. default is false.
 allow_embedding = false
 
+# Set to true if you want to enable http strict transport security (HSTS) response header.
+# This is only sent when HTTPS is enabled in this configuration.
+# HSTS tells browsers that the site should only be accessed using HTTPS.
+# The default will change to true in the next minor release, 6.3.
+strict_transport_security = false
+
+# Sets how long a browser should cache HSTS. Only applied if strict_transport_security is enabled.
+strict_transport_security_max_age_seconds = 86400
+
+# Set to true if to enable HSTS preloading option. Only applied if strict_transport_security is enabled.
+strict_transport_security_preload = false
+
+# Set to true if to enable the HSTS includeSubDomains option. Only applied if strict_transport_security is enabled.
+strict_transport_security_subdomains = false
+
+# Set to true to enable the X-Content-Type-Options response header.
+# The X-Content-Type-Options response HTTP header is a marker used by the server to indicate that the MIME types advertised
+# in the Content-Type headers should not be changed and be followed. The default will change to true in the next minor release, 6.3.
+x_content_type_options = false
+
+# Set to true to enable the X-XSS-Protection header, which tells browsers to stop pages from loading
+# when they detect reflected cross-site scripting (XSS) attacks. The default will change to true in the next minor release, 6.3.
+x_xss_protection = false
+
+
 #################################### Snapshots ###########################
 [snapshots]
 # snapshot sharing options
diff --git a/conf/sample.ini b/conf/sample.ini
index fb1635713b4..528becfbd09 100644
--- a/conf/sample.ini
+++ b/conf/sample.ini
@@ -178,6 +178,30 @@
 # set to true if you want to allow browsers to render Grafana in a <frame>, <iframe>, <embed> or <object>. default is false.
 ;allow_embedding = false
 
+# Set to true if you want to enable http strict transport security (HSTS) response header.
+# This is only sent when HTTPS is enabled in this configuration.
+# HSTS tells browsers that the site should only be accessed using HTTPS.
+# The default version will change to true in the next minor release, 6.3.
+;strict_transport_security = false
+
+# Sets how long a browser should cache HSTS. Only applied if strict_transport_security is enabled.
+;strict_transport_security_max_age_seconds = 86400
+
+# Set to true if to enable HSTS preloading option. Only applied if strict_transport_security is enabled.
+;strict_transport_security_preload = false
+
+# Set to true if to enable the HSTS includeSubDomains option. Only applied if strict_transport_security is enabled.
+;strict_transport_security_subdomains = false
+
+# Set to true to enable the X-Content-Type-Options response header.
+# The X-Content-Type-Options response HTTP header is a marker used by the server to indicate that the MIME types advertised
+# in the Content-Type headers should not be changed and be followed. The default will change to true in the next minor release, 6.3.
+;x_content_type_options = false
+
+# Set to true to enable the X-XSS-Protection header, which tells browsers to stop pages from loading
+# when they detect reflected cross-site scripting (XSS) attacks. The default will change to true in the next minor release, 6.3.
+;x_xss_protection = false
+
 #################################### Snapshots ###########################
 [snapshots]
 # snapshot sharing options
diff --git a/docs/sources/installation/configuration.md b/docs/sources/installation/configuration.md
index 357d23ca1a7..486d63a1e76 100644
--- a/docs/sources/installation/configuration.md
+++ b/docs/sources/installation/configuration.md
@@ -329,6 +329,30 @@ When `false`, the HTTP header `X-Frame-Options: deny` will be set in Grafana HTT
 browsers to not allow rendering Grafana in a `<frame>`, `<iframe>`, `<embed>` or `<object>`. The main goal is to
 mitigate the risk of [Clickjacking](https://www.owasp.org/index.php/Clickjacking). Default is `false`.
 
+### strict_transport_security
+
+Set to `true` if you want to enable http `Strict-Transport-Security` (HSTS) response header. This is only sent when HTTPS is enabled in this configuration. HSTS tells browsers that the site should only be accessed using HTTPS. The default value is `false` until the next minor release, `6.3`.
+
+### strict_transport_security_max_age_seconds
+
+Sets how long a browser should cache HSTS in seconds. Only applied if strict_transport_security is enabled. The default value is `86400`.
+
+### strict_transport_security_preload
+
+Set to `true` if to enable HSTS `preloading` option. Only applied if strict_transport_security is enabled. The default value is `false`.
+
+### strict_transport_security_subdomains
+
+Set to `true` if to enable the HSTS includeSubDomains option. Only applied if strict_transport_security is enabled. The default value is `false`.
+
+### x_content_type_options
+
+Set to `true` to enable the X-Content-Type-Options response header. The X-Content-Type-Options response HTTP header is a marker used by the server to indicate that the MIME types advertised in the Content-Type headers should not be changed and be followed. The default value is `false` until the next minor release, `6.3`.
+
+### x_xss_protection
+
+Set to `false` to disable the X-XSS-Protection header, which tells browsers to stop pages from loading when they detect reflected cross-site scripting (XSS) attacks. The default value is `false` until the next minor release, `6.3`.
+
 <hr />
 
 ## [users]
diff --git a/pkg/middleware/middleware.go b/pkg/middleware/middleware.go
index 1b465e7a4e5..e28054fe250 100644
--- a/pkg/middleware/middleware.go
+++ b/pkg/middleware/middleware.go
@@ -1,6 +1,7 @@
 package middleware
 
 import (
+	"fmt"
 	"net/http"
 	"net/url"
 	"strconv"
@@ -242,10 +243,35 @@ func AddDefaultResponseHeaders() macaron.Handler {
 			if !setting.AllowEmbedding {
 				AddXFrameOptionsDenyHeader(w)
 			}
+
+			AddSecurityHeaders(w)
 		})
 	}
 }
 
+// AddSecurityHeaders adds various HTTP(S) response headers that enable various security protections behaviors in the client's browser.
+func AddSecurityHeaders(w macaron.ResponseWriter) {
+	if setting.Protocol == setting.HTTPS && setting.StrictTransportSecurity {
+		strictHeader := "Strict-Transport-Security"
+		w.Header().Add(strictHeader, fmt.Sprintf("max-age=%v", setting.StrictTransportSecurityMaxAge))
+		if setting.StrictTransportSecurityPreload {
+			w.Header().Add(strictHeader, "preload")
+		}
+		if setting.StrictTransportSecuritySubDomains {
+			w.Header().Add(strictHeader, "includeSubDomains")
+		}
+	}
+
+	if setting.ContentTypeProtectionHeader {
+		w.Header().Add("X-Content-Type-Options", "nosniff")
+	}
+
+	if setting.XSSProtectionHeader {
+		w.Header().Add("X-XSS-Protection", "1")
+		w.Header().Add("X-XSS-Protection", "mode=block")
+	}
+}
+
 func AddNoCacheHeaders(w macaron.ResponseWriter) {
 	w.Header().Add("Cache-Control", "no-cache")
 	w.Header().Add("Pragma", "no-cache")
diff --git a/pkg/setting/setting.go b/pkg/setting/setting.go
index eef813a3afe..05d42f1000e 100644
--- a/pkg/setting/setting.go
+++ b/pkg/setting/setting.go
@@ -87,14 +87,20 @@ var (
 	EnforceDomain      bool
 
 	// Security settings.
-	SecretKey                        string
-	DisableGravatar                  bool
-	EmailCodeValidMinutes            int
-	DataProxyWhiteList               map[string]bool
-	DisableBruteForceLoginProtection bool
-	CookieSecure                     bool
-	CookieSameSite                   http.SameSite
-	AllowEmbedding                   bool
+	SecretKey                         string
+	DisableGravatar                   bool
+	EmailCodeValidMinutes             int
+	DataProxyWhiteList                map[string]bool
+	DisableBruteForceLoginProtection  bool
+	CookieSecure                      bool
+	CookieSameSite                    http.SameSite
+	AllowEmbedding                    bool
+	XSSProtectionHeader               bool
+	ContentTypeProtectionHeader       bool
+	StrictTransportSecurity           bool
+	StrictTransportSecurityMaxAge     int
+	StrictTransportSecurityPreload    bool
+	StrictTransportSecuritySubDomains bool
 
 	// Snapshots
 	ExternalSnapshotUrl   string
@@ -698,6 +704,13 @@ func (cfg *Cfg) Load(args *CommandLineArgs) error {
 
 	AllowEmbedding = security.Key("allow_embedding").MustBool(false)
 
+	ContentTypeProtectionHeader = security.Key("x_content_type_options").MustBool(false)
+	XSSProtectionHeader = security.Key("x_xss_protection").MustBool(false)
+	StrictTransportSecurity = security.Key("strict_transport_security").MustBool(false)
+	StrictTransportSecurityMaxAge = security.Key("strict_transport_security_max_age_seconds").MustInt(86400)
+	StrictTransportSecurityPreload = security.Key("strict_transport_security_preload").MustBool(false)
+	StrictTransportSecuritySubDomains = security.Key("strict_transport_security_subdomains").MustBool(false)
+
 	// read snapshots settings
 	snapshots := iniFile.Section("snapshots")
 	ExternalSnapshotUrl, err = valueAsString(snapshots, "external_snapshot_url", "")