machine init: validate machine name and username

Validate the names with our name regex that we also use for
containers/pods. While we technically do not need to be that strict, I
think it makes sense to match containers. The most important bit of this
validation is that we exclude the use of / and \ which breaks all our
file paths as we just use this in the name an when machine write the
file it ends up being in a subdir which breaks the reading side. Also
other special characters could cause trouble for the URL parsing in the
machine connection URL.

Signed-off-by: Paul Holzinger <pholzing@redhat.com>

Author: Luap99

cmd/podman/machine/init.go

@@ -8,6 +8,7 @@ import (
 
 	"github.com/containers/common/pkg/completion"
 	"github.com/containers/podman/v5/cmd/podman/registry"
+	ldefine "github.com/containers/podman/v5/libpod/define"
 	"github.com/containers/podman/v5/libpod/events"
 	"github.com/containers/podman/v5/pkg/machine"
 	"github.com/containers/podman/v5/pkg/machine/define"
@@ -136,13 +137,21 @@ func initMachine(cmd *cobra.Command, args []string) error {
 			return fmt.Errorf("machine name %q must be %d characters or less", args[0], maxMachineNameSize)
 		}
 		initOpts.Name = args[0]
+
+		if !ldefine.NameRegex.MatchString(initOpts.Name) {
+			return fmt.Errorf("invalid name %q: %w", initOpts.Name, ldefine.RegexError)
+		}
 	}
 
 	// The vmtype names need to be reserved and cannot be used for podman machine names
 	if _, err := define.ParseVMType(initOpts.Name, define.UnknownVirt); err == nil {
 		return fmt.Errorf("cannot use %q for a machine name", initOpts.Name)
 	}
 
+	if !ldefine.NameRegex.MatchString(initOpts.Username) {
+		return fmt.Errorf("invalid username %q: %w", initOpts.Username, ldefine.RegexError)
+	}
+
 	// Check if machine already exists
 	_, exists, err := shim.VMExists(initOpts.Name, []vmconfigs.VMProvider{provider})
 	if err != nil {

pkg/machine/e2e/init_test.go

@@ -66,7 +66,19 @@ var _ = Describe("podman machine init", func() {
 		Expect(badInit).To(Exit(125))
 		Expect(badInit.errorToString()).To(ContainSubstring(want))
 
+		invalidName := "ab/cd"
+		session, err = mb.setName(invalidName).setCmd(&i).run()
+		Expect(err).ToNot(HaveOccurred())
+		Expect(session).To(Exit(125))
+		Expect(session.errorToString()).To(ContainSubstring(`invalid name "ab/cd": names must match [a-zA-Z0-9][a-zA-Z0-9_.-]*: invalid argument`))
+
+		i.username = "-/a"
+		session, err = mb.setName("").setCmd(&i).run()
+		Expect(err).ToNot(HaveOccurred())
+		Expect(session).To(Exit(125))
+		Expect(session.errorToString()).To(ContainSubstring(`invalid username "-/a": names must match [a-zA-Z0-9][a-zA-Z0-9_.-]*: invalid argument`))
 	})
+
 	It("simple init", func() {
 		i := new(initMachine)
 		session, err := mb.setCmd(i.withImagePath(mb.imagePath)).run()