fix: add validation for containerID

Signed-off-by: karthik balasubramanian <karthikbalasubramanian08@gmail.com>

Author: kaizakin

cmd/urunc/create.go

@@ -94,6 +94,9 @@ func createUnikontainer(cmd *cli.Command, uruncCfg *unikontainers.UruncConfig) (
 		err = fmt.Errorf("container id cannot be empty")
 		return err
 	}
+	if err = validateID(containerID); err != nil {
+		return err
+	}
 	metrics.SetLoggerContainerID(containerID)
 	metrics.Capture(m.TS00)
 

cmd/urunc/utils.go

@@ -21,6 +21,7 @@ import (
 	"os"
 	"os/exec"
 	"syscall"
+	"path/filepath"
 
 	"github.com/moby/sys/userns"
 	"github.com/sirupsen/logrus"
@@ -37,6 +38,7 @@ const (
 )
 
 var ErrEmptyContainerID = errors.New("container ID can not be empty")
+var ErrInvalidID = errors.New("invalid container id format")
 
 // checkArgs checks the number of arguments provided in the command-line context
 // against the expected number, based on the specified checkType.
@@ -72,6 +74,9 @@ func getUnikontainer(cmd *cli.Command) (*unikontainers.Unikontainer, error) {
 	if containerID == "" {
 		return nil, ErrEmptyContainerID
 	}
+	if err := validateID(containerID); err != nil {
+		return nil, err
+	}
 
 	// We have already made sure in main.go that root is not nil
 	rootDir := cmd.String("root")
@@ -160,3 +165,33 @@ func prepareXDGRuntimeDir(root string) error {
 	}
 	return nil
 }
+
+// validateID validates the given ID string against the allowed characters.
+func validateID(id string) error {
+	if len(id) < 1 {
+		return ErrInvalidID
+	}
+
+	// Allowed characters: 0-9 A-Z a-z _ + - .
+	for i := range len(id) {
+		c := id[i]
+		switch {
+		case c >= 'a' && c <= 'z':
+		case c >= 'A' && c <= 'Z':
+		case c >= '0' && c <= '9':
+		case c == '_':
+		case c == '+':
+		case c == '-':
+		case c == '.':
+		default:
+			return ErrInvalidID
+		}
+
+	}
+
+	if string(os.PathSeparator)+id != filepath.Clean(string(os.PathSeparator)+id) {
+		return ErrInvalidID
+	}
+
+	return nil
+}