Add support for enabling AWS Shield Advanced protection

docs/examples/iam-policy.json

@@ -113,6 +113,18 @@
         "waf:GetWebACL"
       ],
       "Resource": "*"
+    },
+    {
+      "Effect": "Allow",
+      "Action": [
+        "shield:DescribeProtection",
+        "shield:GetSubscriptionState",
+        "shield:DeleteProtection",
+        "shield:CreateProtection",
+        "shield:DescribeSubscription",
+        "shield:ListProtections"
+      ],
+      "Resource": "*"
     }
   ]
 }

docs/guide/ingress/annotation.md

@@ -4,6 +4,7 @@ You can add kubernetes annotations to ingress and service objects to customize t
 !!!note
     - Annotations applied to service have higher priority over annotations applied to ingress. `Location` column below indicates where that annotation can be applied to.
     - Annotation keys and values can only be strings. Advanced format are encoded as below:
+        - boolean: 'true'
         - integer: '42'
         - stringMap: k1=v1,k2=v2
         - stringList: s1,s2,s3
@@ -37,6 +38,7 @@ You can add kubernetes annotations to ingress and service objects to customize t
 |[alb.ingress.kubernetes.io/load-balancer-attributes](#load-balancer-attributes)|stringMap|N/A|ingress|
 |[alb.ingress.kubernetes.io/scheme](#scheme)|internal \| internet-facing|internal|ingress|
 |[alb.ingress.kubernetes.io/security-groups](#security-groups)|stringList|N/A|ingress|
+|[alb.ingress.kubernetes.io/shield-advanced-protection](#shield-advanced-protection)|boolean|N/A|ingress|
 |[alb.ingress.kubernetes.io/ssl-policy](#ssl-policy)|string|ELBSecurityPolicy-2016-08|ingress|
 |[alb.ingress.kubernetes.io/subnets](#subnets)|stringList|N/A|ingress|
 |[alb.ingress.kubernetes.io/success-codes](#success-codes)|string|'200'|ingress,service|
@@ -488,6 +490,13 @@ Health check on target groups can be controlled with following annotations:
         ```alb.ingress.kubernetes.io/waf-acl-id: 499e8b99-6671-4614-a86d-adb1810b7fbe
         ```
 
+## Shield Advanced
+- <a name="shield-advanced-protection">`alb.ingress.kubernetes.io/shield-advanced-protection`</a> turns on / off the AWS Shield Advanced protection for the load balancer.
+
+    !!!example
+        ```alb.ingress.kubernetes.io/shield-advanced-protection: 'true'
+        ```
+
 ## SSL
 SSL support can be controlled with following annotations:
 

internal/alb/lb/loadbalancer.go

@@ -46,6 +46,7 @@ func NewController(
 	tagsController tags.Controller) Controller {
 	attrsController := NewAttributesController(cloud)
 	wafController := NewWAFController(cloud)
+	shieldController := NewShieldController(cloud)
 
 	return &defaultController{
 		cloud:                   cloud,
@@ -57,6 +58,7 @@ func NewController(
 		tagsController:          tagsController,
 		attrsController:         attrsController,
 		wafController:           wafController,
+		shieldController:        shieldController,
 	}
 }
 
@@ -81,6 +83,7 @@ type defaultController struct {
 	tagsController          tags.Controller
 	attrsController         AttributesController
 	wafController           WAFController
+	shieldController        ShieldController
 }
 
 var _ Controller = (*defaultController)(nil)
@@ -119,6 +122,12 @@ func (controller *defaultController) Reconcile(ctx context.Context, ingress *ext
 		}
 	}
 
+	if controller.store.GetConfig().FeatureGate.Enabled(config.ShieldAdvanced) {
+		if err := controller.shieldController.Reconcile(ctx, lbArn, ingress); err != nil {
+			return nil, err
+		}
+	}
+
 	tgGroup, err := controller.tgGroupController.Reconcile(ctx, ingress)
 	if err != nil {
 		return nil, fmt.Errorf("failed to reconcile targetGroups due to %v", err)

internal/alb/lb/shield.go

@@ -0,0 +1,129 @@
+package lb
+
+import (
+	"context"
+	"fmt"
+	"strconv"
+	"time"
+
+	"github.com/kubernetes-sigs/aws-alb-ingress-controller/internal/ingress/annotations"
+
+	"github.com/aws/aws-sdk-go/service/shield"
+	"github.com/kubernetes-sigs/aws-alb-ingress-controller/internal/albctx"
+	"github.com/kubernetes-sigs/aws-alb-ingress-controller/internal/aws"
+	"github.com/pkg/errors"
+	extensions "k8s.io/api/extensions/v1beta1"
+
+	"k8s.io/apimachinery/pkg/util/cache"
+)
+
+const (
+	protectionEnabledForLBCacheMaxSize = 1024
+	protectionEnabledForLBCacheTTL     = 10 * time.Second
+	shieldAvailableCacheMaxSize        = 1
+	shieldAvailableCacheTTL            = 10 * time.Second
+	shieldAvailableCacheKey            = "shieldAvailable"
+	protectionName                     = "managed by aws-alb-ingress-controller"
+)
+
+// ShieldController provides functionality to manage ALB's Shield Advanced protection.
+type ShieldController interface {
+	Reconcile(ctx context.Context, lbArn string, ingress *extensions.Ingress) error
+}
+
+func NewShieldController(cloud aws.CloudAPI) ShieldController {
+	return &defaultShieldController{
+		cloud:                       cloud,
+		protectionEnabledForLBCache: cache.NewLRUExpireCache(protectionEnabledForLBCacheMaxSize),
+		shieldAvailableCache:        cache.NewLRUExpireCache(shieldAvailableCacheMaxSize),
+	}
+}
+
+type defaultShieldController struct {
+	cloud aws.CloudAPI
+
+	// cache that stores protection id for LoadBalancerARN.
+	// The cache value is string, while "" represents no protection.
+	protectionEnabledForLBCache *cache.LRUExpireCache
+	// cache that stores shield availability for current account.
+	// The cache value is string, while "" represents not available.
+	shieldAvailableCache *cache.LRUExpireCache
+}
+
+func (c *defaultShieldController) Reconcile(ctx context.Context, lbArn string, ingress *extensions.Ingress) error {
+	var enableProtection bool
+	annotationPresent, err := annotations.LoadBoolAnnocation("shield-advanced-protection", &enableProtection, ingress.Annotations)
+	if err != nil {
+		return err
+	}
+	if !annotationPresent {
+		return nil
+	}
+
+	available, err := c.getCurrentShieldAvailability(ctx)
+	if err != nil {
+		return err
+	}
+
+	if enableProtection && !available {
+		return fmt.Errorf("unable to create shield advanced protection for loadBalancer %v, shield advanced subscription is not active", lbArn)
+	}
+
+	protection, err := c.getCurrentProtectionStatus(ctx, lbArn)
+	if err != nil {
+		return fmt.Errorf("failed to get shield advanced protection status for loadBalancer %v due to %v", lbArn, err)
+	}
+
+	if protection == nil && enableProtection {
+		_, err := c.cloud.CreateProtection(ctx, aws.String(lbArn), aws.String(protectionName))
+		if err != nil {
+			return fmt.Errorf("failed to create shield advanced protection for loadBalancer %v due to %v", lbArn, err)
+		}
+		albctx.GetLogger(ctx).Infof("enabled shield advanced protection for %v", lbArn)
+	} else if protection != nil && !enableProtection {
+		if aws.StringValue(protection.Name) == protectionName {
+			_, err := c.cloud.DeleteProtection(ctx, protection.Id)
+			c.protectionEnabledForLBCache.Remove(lbArn)
+			if err != nil {
+				return fmt.Errorf("failed to delete shield advanced protection for loadBalancer %v due to %v", lbArn, err)
+			}
+
+			albctx.GetLogger(ctx).Infof("deleted shield advanced protection for %v", lbArn)
+		} else {
+			albctx.GetLogger(ctx).Warnf("unable to delete shield advanced protection for %v, the protection name does not match \"%v\"", lbArn, protectionName)
+		}
+	}
+	return nil
+}
+
+func (c *defaultShieldController) getCurrentShieldAvailability(ctx context.Context) (bool, error) {
+	cachedShieldAvailable, exists := c.shieldAvailableCache.Get(shieldAvailableCacheKey)
+	if exists {
+		available, err := strconv.ParseBool(cachedShieldAvailable.(string))
+		if err == nil {
+			return available, nil
+		}
+	}
+
+	available, err := c.cloud.ShieldAvailable(ctx)
+	if err != nil {
+		return false, fmt.Errorf("failed to get shield advanced subscription state %v", err)
+	}
+	c.shieldAvailableCache.Add(shieldAvailableCacheKey, "true", shieldAvailableCacheTTL)
+	return available, nil
+}
+
+func (c *defaultShieldController) getCurrentProtectionStatus(ctx context.Context, lbArn string) (*shield.Protection, error) {
+	cachedProtection, exists := c.protectionEnabledForLBCache.Get(lbArn)
+	if exists {
+		return cachedProtection.(*shield.Protection), nil
+	}
+
+	protection, err := c.cloud.GetProtection(ctx, aws.String(lbArn))
+	if err != nil {
+		return nil, errors.Wrapf(err, "failed to get protection status for load balancer %v", lbArn)
+	}
+
+	c.protectionEnabledForLBCache.Add(lbArn, protection, protectionEnabledForLBCacheTTL)
+	return protection, nil
+}