Add validation on username

Signed-off-by: Kyle Spiers <kyle@spiers.me>

core/core.go

@@ -8,6 +8,7 @@ import (
 	"errors"
 	"fmt"
 	"log"
+	"regexp"
 	"strconv"
 	"strings"
 	"time"
@@ -219,10 +220,13 @@ func validateUser(name, password string, admin bool) error {
 	return nil
 }
 
+//Username must start with an alphanumeric character and can include "-" and "_" after the first
+var validName = regexp.MustCompile(`^[A-Za-z0-9][A-Za-z0-9\_\-]*$`).MatchString
+
 // validateName checks that the username and password pass a validation test.
 func validateName(name, password string) error {
-	if name == "" {
-		return errors.New("User name must not be blank")
+	if !validName(name) {
+		return errors.New("must start with an alphanumeric character and can include \"-\" or \"_\" after the first character")
 	}
 	if password == "" {
 		return errors.New("Password must be at least one character")

core/core_test.go

@@ -1174,6 +1174,16 @@ func TestValidateName(t *testing.T) {
 		t.Fatal("Error expected when no name is provided")
 	}
 
+	err = validateName("?", "password")
+	if err == nil {
+		t.Fatal("Error expected when non alphanumeric is used in name")
+	}
+
+	err = validateName("-name", "password")
+	if err == nil {
+		t.Fatal("Error expected when name starts with '-' or '_'")
+	}
+
 	err = validateName("username", "")
 	if err == nil {
 		t.Fatal("Error expected when no password is provided")