From 5f528e9c07110332f18bea5be5668a12a61def0a Mon Sep 17 00:00:00 2001
From: Leon Klingele <git@leonklingele.de>
Date: Mon, 22 Feb 2016 17:07:28 +0100
Subject: [PATCH 1/2] Add missing characters to random string function, so we
 use the full upper+lowercase alphabet

---
 src/app/spreed-webrtc-server/random.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/app/spreed-webrtc-server/random.go b/src/app/spreed-webrtc-server/random.go
index a884cd5b..c498c7e5 100644
--- a/src/app/spreed-webrtc-server/random.go
+++ b/src/app/spreed-webrtc-server/random.go
@@ -28,7 +28,7 @@ import (
 )
 
 const (
-	dict = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVW0123456789"
+	dict = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
 )
 
 func NewRandomString(length int) string {

From b6570a28128dae8e1033297450458baf38eb4aa8 Mon Sep 17 00:00:00 2001
From: Leon Klingele <git@leonklingele.de>
Date: Mon, 22 Feb 2016 17:08:42 +0100
Subject: [PATCH 2/2] cryptoRand.Int / pseudoRand.Intn to generate random
 integer. Previous way was modulo-biased

---
 src/app/spreed-webrtc-server/random.go | 26 ++++++++++++++++----------
 1 file changed, 16 insertions(+), 10 deletions(-)

diff --git a/src/app/spreed-webrtc-server/random.go b/src/app/spreed-webrtc-server/random.go
index c498c7e5..f2afa7d6 100644
--- a/src/app/spreed-webrtc-server/random.go
+++ b/src/app/spreed-webrtc-server/random.go
@@ -23,6 +23,7 @@ package main
 
 import (
 	"crypto/rand"
+	"math/big"
 	pseudoRand "math/rand"
 	"time"
 )
@@ -31,19 +32,24 @@ const (
 	dict = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
 )
 
+// NewRandomInt returns a random integer in range [0, max[
+// Tries to use crypto/rand and falls back to math/rand
+func NewRandomInt(max int) int {
+
+	rand, err := rand.Int(rand.Reader, big.NewInt(int64(max)))
+	if err != nil {
+		// Fallback to pseudo-random
+		return pseudoRand.Intn(max)
+	}
+	return int(rand.Int64())
+
+}
+
 func NewRandomString(length int) string {
 
 	buf := make([]byte, length)
-	_, err := rand.Read(buf)
-	if err != nil {
-		// fallback to pseudo-random
-		for i := 0; i < length; i++ {
-			buf[i] = dict[pseudoRand.Intn(len(dict))]
-		}
-	} else {
-		for i := 0; i < length; i++ {
-			buf[i] = dict[int(buf[i])%len(dict)]
-		}
+	for i := 0; i < length; i++ {
+		buf[i] = dict[NewRandomInt(len(dict))]
 	}
 	return string(buf)