From 31333eecae172678c5ce2dd4e76c511bb6a19649 Mon Sep 17 00:00:00 2001
From: Sean Chittenden <sean@chittenden.org>
Date: Thu, 2 Feb 2017 16:24:32 -0800
Subject: [PATCH] Add better verification of a host's HostID.

---
 client/client.go |  3 ++-
 helper/funcs.go  | 15 +++++++++++++++
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/client/client.go b/client/client.go
index 3ad8f07bd..16b3ac401 100644
--- a/client/client.go
+++ b/client/client.go
@@ -27,6 +27,7 @@ import (
 	"github.com/hashicorp/nomad/client/stats"
 	"github.com/hashicorp/nomad/client/vaultclient"
 	"github.com/hashicorp/nomad/command/agent/consul"
+	"github.com/hashicorp/nomad/helper"
 	"github.com/hashicorp/nomad/helper/tlsutil"
 	"github.com/hashicorp/nomad/nomad"
 	"github.com/hashicorp/nomad/nomad/structs"
@@ -636,7 +637,7 @@ func (c *Client) getAllocRunners() map[string]*AllocRunner {
 func (c *Client) nodeID() (id, secret string, err error) {
 	var hostID string
 	hostInfo, err := host.Info()
-	if err == nil && hostInfo.HostID != "" {
+	if err == nil && helper.IsUUID(hostInfo.HostID) {
 		hostID = hostInfo.HostID
 	} else {
 		// Generate a random hostID if no constant ID is available on
diff --git a/helper/funcs.go b/helper/funcs.go
index 653c3a100..89538f42c 100644
--- a/helper/funcs.go
+++ b/helper/funcs.go
@@ -1,5 +1,20 @@
 package helper
 
+import "regexp"
+
+// validUUID is used to check if a given string looks like a UUID
+var validUUID = regexp.MustCompile(`(?i)^[\da-f]{8}-[\da-f]{4}-[\da-f]{4}-[\da-f]{4}-[\da-f]{12}$`)
+
+// IsUUID returns true if the given string is a valid UUID.
+func IsUUID(str string) bool {
+	const uuidLen = 36
+	if len(str) != uuidLen {
+		return false
+	}
+
+	return validUUID.MatchString(str)
+}
+
 // boolToPtr returns the pointer to a boolean
 func BoolToPtr(b bool) *bool {
 	return &b