From 00e41888b09783acd7372c309360bf22f45bd3ef Mon Sep 17 00:00:00 2001
From: Anirudh <ramanathana@google.com>
Date: Wed, 24 Aug 2016 16:47:08 -0700
Subject: [PATCH] Fixed integer overflow bug in rate limiter.

---
 pkg/util/workqueue/default_rate_limiters.go   |  9 ++++-
 .../workqueue/default_rate_limiters_test.go   | 33 +++++++++++++++++++
 2 files changed, 41 insertions(+), 1 deletion(-)

diff --git a/pkg/util/workqueue/default_rate_limiters.go b/pkg/util/workqueue/default_rate_limiters.go
index cf3c4d94eac..8b281158147 100644
--- a/pkg/util/workqueue/default_rate_limiters.go
+++ b/pkg/util/workqueue/default_rate_limiters.go
@@ -90,9 +90,16 @@ func (r *ItemExponentialFailureRateLimiter) When(item interface{}) time.Duration
 	r.failuresLock.Lock()
 	defer r.failuresLock.Unlock()
 
+	exp := r.failures[item]
 	r.failures[item] = r.failures[item] + 1
 
-	calculated := r.baseDelay * time.Duration(math.Pow10(r.failures[item]-1))
+	// The backoff is capped such that 'calculated' value never overflows.
+	backoff := float64(r.baseDelay.Nanoseconds()) * math.Pow10(exp)
+	if backoff > math.MaxInt64 {
+		return r.maxDelay
+	}
+
+	calculated := time.Duration(backoff)
 	if calculated > r.maxDelay {
 		return r.maxDelay
 	}
diff --git a/pkg/util/workqueue/default_rate_limiters_test.go b/pkg/util/workqueue/default_rate_limiters_test.go
index 3ce3144ff6d..e50cf453f03 100644
--- a/pkg/util/workqueue/default_rate_limiters_test.go
+++ b/pkg/util/workqueue/default_rate_limiters_test.go
@@ -63,6 +63,39 @@ func TestItemExponentialFailureRateLimiter(t *testing.T) {
 
 }
 
+func TestItemExponentialFailureRateLimiterOverFlow(t *testing.T) {
+	limiter := NewItemExponentialFailureRateLimiter(1*time.Millisecond, 1000*time.Second)
+	for i := 0; i < 5; i++ {
+		limiter.When("one")
+	}
+	if e, a := 100000*time.Millisecond, limiter.When("one"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+
+	for i := 0; i < 1000; i++ {
+		limiter.When("overflow1")
+	}
+	if e, a := 1000*time.Second, limiter.When("overflow1"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+
+	limiter = NewItemExponentialFailureRateLimiter(1*time.Minute, 1000*time.Hour)
+	for i := 0; i < 2; i++ {
+		limiter.When("two")
+	}
+	if e, a := 100*time.Minute, limiter.When("two"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+
+	for i := 0; i < 1000; i++ {
+		limiter.When("overflow2")
+	}
+	if e, a := 1000*time.Hour, limiter.When("overflow2"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+
+}
+
 func TestItemFastSlowRateLimiter(t *testing.T) {
 	limiter := NewItemFastSlowRateLimiter(5*time.Millisecond, 10*time.Second, 3)