Backport of Add command "nomad tls" into release/1.4.x

.changelog/14296.txt

@@ -0,0 +1,4 @@
+```release-note:improvement
+cli: Added tls command to enable creating Certificate Authority and Self signed TLS certificates.
+There are two sub commands `tls ca` and `tls cert` that are helpers when creating certificates.
+```

command/commands.go

@@ -926,6 +926,41 @@ func Commands(metaPtr *Meta, agentUi cli.Ui) map[string]cli.CommandFactory {
 				Meta: meta,
 			}, nil
 		},
+		"tls": func() (cli.Command, error) {
+			return &TLSCommand{
+				Meta: meta,
+			}, nil
+		},
+		"tls ca": func() (cli.Command, error) {
+			return &TLSCACommand{
+				Meta: meta,
+			}, nil
+		},
+		"tls ca create": func() (cli.Command, error) {
+			return &TLSCACreateCommand{
+				Meta: meta,
+			}, nil
+		},
+		"tls ca info": func() (cli.Command, error) {
+			return &TLSCAInfoCommand{
+				Meta: meta,
+			}, nil
+		},
+		"tls cert": func() (cli.Command, error) {
+			return &TLSCertCommand{
+				Meta: meta,
+			}, nil
+		},
+		"tls cert create": func() (cli.Command, error) {
+			return &TLSCertCreateCommand{
+				Meta: meta,
+			}, nil
+		},
+		"tls cert info": func() (cli.Command, error) {
+			return &TLSCertInfoCommand{
+				Meta: meta,
+			}, nil
+		},
 		"ui": func() (cli.Command, error) {
 			return &UiCommand{
 				Meta: meta,

command/tls.go

@@ -0,0 +1,56 @@
+package command
+
+import (
+	"os"
+	"strings"
+
+	"github.com/mitchellh/cli"
+)
+
+type TLSCommand struct {
+	Meta
+}
+
+func fileDoesNotExist(file string) bool {
+	if _, err := os.Stat(file); os.IsNotExist(err) {
+		return true
+	}
+	return false
+}
+
+func (c *TLSCommand) Help() string {
+	helpText := `
+Usage: nomad tls <subcommand> <subcommand> [options]
+
+This command groups subcommands for creating certificates for Nomad TLS configuration. 
+The TLS command allows operators to generate self signed certificates to use
+when securing your Nomad cluster.
+
+Some simple examples for creating certificates can be found here.
+More detailed examples are available in the subcommands or the documentation.
+
+Create a CA
+
+    $ nomad tls ca create
+
+Create a server certificate
+
+    $ nomad tls cert create -server
+
+Create a client certificate
+
+    $ nomad tls cert create -client
+
+`
+	return strings.TrimSpace(helpText)
+}
+
+func (c *TLSCommand) Synopsis() string {
+	return "Generate Self Signed TLS Certificates for Nomad"
+}
+
+func (c *TLSCommand) Name() string { return "tls" }
+
+func (c *TLSCommand) Run(_ []string) int {
+	return cli.RunResultHelp
+}

command/tls_ca.go

@@ -0,0 +1,44 @@
+package command
+
+import (
+	"strings"
+
+	"github.com/mitchellh/cli"
+	"github.com/posener/complete"
+)
+
+type TLSCACommand struct {
+	Meta
+}
+
+func (c *TLSCACommand) Help() string {
+	helpText := `
+Usage: nomad tls ca <subcommand> [options]
+
+  This command groups subcommands for interacting with certificate authorities.
+  For examples, see the documentation.
+
+  Create a certificate authority.
+
+      $ nomad tls ca create
+
+  Show information about a certificate authority.
+
+      $ nomad tls ca info
+`
+	return strings.TrimSpace(helpText)
+}
+
+func (c *TLSCACommand) AutocompleteArgs() complete.Predictor {
+	return complete.PredictNothing
+}
+
+func (c *TLSCACommand) Synopsis() string {
+	return "Helpers for managing certificate authorities"
+}
+
+func (c *TLSCACommand) Name() string { return "tls ca" }
+
+func (c *TLSCACommand) Run(_ []string) int {
+	return cli.RunResultHelp
+}

command/tls_ca_create.go

@@ -0,0 +1,162 @@
+package command
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/posener/complete"
+
+	"github.com/hashicorp/nomad/helper/flags"
+	"github.com/hashicorp/nomad/helper/tlsutil"
+	"github.com/hashicorp/nomad/lib/file"
+)
+
+type TLSCACreateCommand struct {
+	Meta
+
+	// days is the number of days the CA will be valid for
+	days int
+
+	// constraint boolean enables the name constraint option in the CA which
+	// will then reject any domains other than the ones stiputalted in -domain
+	// and -addtitional-domain.
+	constraint bool
+
+	// domain is used to provide a custom domain for the CA
+	domain string
+
+	// commonName is used to set a common name for the CA
+	commonName string
+
+	// additionalDomain provides a list of restricted domains to the CA which
+	// will then reject any domains other than these.
+	additionalDomain flags.StringFlag
+}
+
+func (c *TLSCACreateCommand) Help() string {
+	helpText := `
+Usage: nomad tls ca create [options]
+
+  Create a new certificate authority.
+
+CA Create Options:
+
+  -additional-domain
+    Add additional DNS zones to the allowed list for the CA. The server will
+    reject certificates for DNS names other than those specified in -domain and
+    -additional-domain. This flag can be used multiple times. Only used in
+    combination with -domain and -name-constraint.
+
+  -common-name
+    Common Name of CA. Defaults to "Nomad Agent CA".
+
+  -days
+    Provide number of days the CA is valid for from now on.
+    Defaults to 5 years or 1825 days.
+
+  -domain
+    Domain of Nomad cluster. Only used in combination with -name-constraint.
+    Defaults to "nomad".
+
+  -name-constraint
+    Enables the DNS name restriction functionality to the CA. Results in the CA
+    rejecting certificates for any other DNS zone. If enabled, localhost and the
+    value of -domain will be added to the allowed DNS zones field. If the UI is
+    going to be served over HTTPS its hostname must be added with
+    -additional-domain. Defaults to false.
+`
+	return strings.TrimSpace(helpText)
+}
+
+func (c *TLSCACreateCommand) AutocompleteFlags() complete.Flags {
+	return mergeAutocompleteFlags(c.Meta.AutocompleteFlags(FlagSetClient),
+		complete.Flags{
+			"-additional-domain": complete.PredictAnything,
+			"-common-name":       complete.PredictAnything,
+			"-days":              complete.PredictAnything,
+			"-domain":            complete.PredictAnything,
+			"-name-constraint":   complete.PredictAnything,
+		})
+}
+
+func (c *TLSCACreateCommand) AutocompleteArgs() complete.Predictor {
+	return complete.PredictNothing
+}
+
+func (c *TLSCACreateCommand) Synopsis() string {
+	return "Create a certificate authority for Nomad"
+}
+
+func (c *TLSCACreateCommand) Name() string { return "tls ca create" }
+
+func (c *TLSCACreateCommand) Run(args []string) int {
+
+	flagSet := c.Meta.FlagSet(c.Name(), FlagSetClient)
+	flagSet.Usage = func() { c.Ui.Output(c.Help()) }
+	flagSet.Var(&c.additionalDomain, "additional-domain", "")
+	flagSet.IntVar(&c.days, "days", 1825, "")
+	flagSet.BoolVar(&c.constraint, "name-constraint", false, "")
+	flagSet.StringVar(&c.domain, "domain", "nomad", "")
+	flagSet.StringVar(&c.commonName, "common-name", "", "")
+	if err := flagSet.Parse(args); err != nil {
+		return 1
+	}
+
+	// Check that we got no arguments
+	args = flagSet.Args()
+	if l := len(args); l < 0 || l > 1 {
+		c.Ui.Error("This command takes up to one argument")
+		c.Ui.Error(commandErrorText(c))
+		return 1
+	}
+	if c.domain != "" && c.domain != "nomad" && !c.constraint {
+		c.Ui.Error("Please provide the -name-constraint flag to use a custom domain constraint")
+		return 1
+	}
+	if c.domain == "nomad" && c.constraint {
+		c.Ui.Error("Please provide the -domain flag if you want to enable custom domain constraints")
+		return 1
+	}
+	if c.additionalDomain != nil && c.domain == "" && !c.constraint {
+		c.Ui.Error("Please provide the -name-constraint flag to use a custom domain constraints")
+		return 1
+	}
+
+	certFileName := fmt.Sprintf("%s-agent-ca.pem", c.domain)
+	pkFileName := fmt.Sprintf("%s-agent-ca-key.pem", c.domain)
+
+	if !(fileDoesNotExist(certFileName)) {
+		c.Ui.Error(fmt.Sprintf("CA certificate file '%s' already exists", certFileName))
+		return 1
+	}
+	if !(fileDoesNotExist(pkFileName)) {
+		c.Ui.Error(fmt.Sprintf("CA key file '%s' already exists", pkFileName))
+		return 1
+	}
+
+	constraints := []string{}
+	if c.constraint {
+		constraints = []string{c.domain, "localhost"}
+		constraints = append(constraints, c.additionalDomain...)
+	}
+
+	ca, pk, err := tlsutil.GenerateCA(tlsutil.CAOpts{Name: c.commonName, Days: c.days, Domain: c.domain, PermittedDNSDomains: constraints})
+	if err != nil {
+		c.Ui.Error(err.Error())
+		return 1
+	}
+
+	if err := file.WriteAtomicWithPerms(certFileName, []byte(ca), 0755, 0666); err != nil {
+		c.Ui.Error(err.Error())
+		return 1
+	}
+	c.Ui.Output("==> CA certificate saved to: " + certFileName)
+
+	if err := file.WriteAtomicWithPerms(pkFileName, []byte(pk), 0755, 0600); err != nil {
+		c.Ui.Error(err.Error())
+		return 1
+	}
+	c.Ui.Output("==> CA certificate key saved to: " + pkFileName)
+
+	return 0
+}