Adds ID validation.

Docker-DCO-1.1-Signed-off-by: Mrunal Patel <mrunalp@gmail.com> (github: mrunalp)

linux_factory.go

@@ -4,8 +4,10 @@ package libcontainer
 
 import (
 	"encoding/json"
+	"fmt"
 	"os"
 	"path/filepath"
+	"regexp"
 
 	"github.com/Sirupsen/logrus"
 )
@@ -15,6 +17,10 @@ const (
 	stateFilename  = "state.json"
 )
 
+var (
+	idRegex = regexp.MustCompile(`^[\w_]{1,1024}$`)
+)
+
 // New returns a linux based container factory based in the root directory.
 func New(root string, logger *logrus.Logger) (Factory, error) {
 	if err := os.MkdirAll(root, 0700); err != nil {
@@ -37,6 +43,10 @@ type linuxFactory struct {
 }
 
 func (l *linuxFactory) Create(id string, config *Config) (Container, error) {
+	if !idRegex.MatchString(id) {
+		return nil, newGenericError(fmt.Errorf("Invalid id format: %s ", id), InvalidIdFormat)
+	}
+
 	panic("not implemented")
 }