From f424085f44bff1f4392455d57bf897707d071988 Mon Sep 17 00:00:00 2001
From: Radek Simko <radek.simko@timeinc.com>
Date: Thu, 25 Jun 2015 11:20:54 +0100
Subject: [PATCH] provider/aws: Add validation for aws_vpc.cidr_block

 - closes #2340
---
 builtin/providers/aws/resource_aws_vpc.go | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/builtin/providers/aws/resource_aws_vpc.go b/builtin/providers/aws/resource_aws_vpc.go
index 2ee2473b2..f8c5217cb 100644
--- a/builtin/providers/aws/resource_aws_vpc.go
+++ b/builtin/providers/aws/resource_aws_vpc.go
@@ -3,6 +3,7 @@ package aws
 import (
 	"fmt"
 	"log"
+	"net"
 	"time"
 
 	"github.com/aws/aws-sdk-go/aws"
@@ -24,6 +25,16 @@ func resourceAwsVpc() *schema.Resource {
 				Type:     schema.TypeString,
 				Required: true,
 				ForceNew: true,
+				ValidateFunc: func(v interface{}, k string) (ws []string, errors []error) {
+					value := v.(string)
+					_, ipnet, err := net.ParseCIDR(value)
+
+					if err != nil || ipnet == nil || value != ipnet.String() {
+						errors = append(errors, fmt.Errorf(
+							"%q must contain a valid CIDR", k))
+					}
+					return
+				},
 			},
 
 			"instance_tenancy": &schema.Schema{