package main import ( "context" "crypto" "crypto/rand" "crypto/sha1" "crypto/x509" "crypto/x509/pkix" "encoding/pem" "flag" "fmt" "math/big" "os" "time" "github.com/smallstep/certificates/kms/apiv1" "github.com/smallstep/certificates/kms/awskms" "github.com/smallstep/cli/crypto/pemutil" "github.com/smallstep/cli/ui" "github.com/smallstep/cli/utils" "golang.org/x/crypto/ssh" ) func main() { var credentialsFile, region string var ssh bool flag.StringVar(&credentialsFile, "credentials-file", "", "Path to the `file` containing the AWS KMS credentials.") flag.StringVar(®ion, "region", "", "AWS KMS region name.") flag.BoolVar(&ssh, "ssh", false, "Create SSH keys.") flag.Usage = usage flag.Parse() c, err := awskms.New(context.Background(), apiv1.Options{ Type: string(apiv1.AmazonKMS), Region: region, CredentialsFile: credentialsFile, }) if err != nil { fatal(err) } if err := createPKI(c); err != nil { fatal(err) } if ssh { ui.Println() if err := createSSH(c); err != nil { fatal(err) } } } func fatal(err error) { fmt.Fprintln(os.Stderr, err) os.Exit(1) } func usage() { fmt.Fprintln(os.Stderr, "Usage: step-awskms-init") fmt.Fprintln(os.Stderr, ` The step-awskms-init command initializes a public key infrastructure (PKI) to be used by step-ca. This tool is experimental and in the future it will be integrated in step cli. OPTIONS`) fmt.Fprintln(os.Stderr) flag.PrintDefaults() fmt.Fprintln(os.Stderr, ` COPYRIGHT (c) 2018-2020 Smallstep Labs, Inc.`) os.Exit(1) } func createPKI(c *awskms.KMS) error { ui.Println("Creating PKI ...") // Root Certificate resp, err := c.CreateKey(&apiv1.CreateKeyRequest{ Name: "root", SignatureAlgorithm: apiv1.ECDSAWithSHA256, }) if err != nil { return err } signer, err := c.CreateSigner(&resp.CreateSignerRequest) if err != nil { return err } now := time.Now() root := &x509.Certificate{ IsCA: true, NotBefore: now, NotAfter: now.Add(time.Hour * 24 * 365 * 10), KeyUsage: x509.KeyUsageCertSign | x509.KeyUsageCRLSign, BasicConstraintsValid: true, MaxPathLen: 1, MaxPathLenZero: false, Issuer: pkix.Name{CommonName: "Smallstep Root"}, Subject: pkix.Name{CommonName: "Smallstep Root"}, SerialNumber: mustSerialNumber(), SubjectKeyId: mustSubjectKeyID(resp.PublicKey), AuthorityKeyId: mustSubjectKeyID(resp.PublicKey), } b, err := x509.CreateCertificate(rand.Reader, root, root, resp.PublicKey, signer) if err != nil { return err } if err = utils.WriteFile("root_ca.crt", pem.EncodeToMemory(&pem.Block{ Type: "CERTIFICATE", Bytes: b, }), 0600); err != nil { return err } ui.PrintSelected("Root Key", resp.Name) ui.PrintSelected("Root Certificate", "root_ca.crt") root, err = pemutil.ReadCertificate("root_ca.crt") if err != nil { return err } // Intermediate Certificate resp, err = c.CreateKey(&apiv1.CreateKeyRequest{ Name: "intermediate", SignatureAlgorithm: apiv1.ECDSAWithSHA256, }) if err != nil { return err } intermediate := &x509.Certificate{ IsCA: true, NotBefore: now, NotAfter: now.Add(time.Hour * 24 * 365 * 10), KeyUsage: x509.KeyUsageCertSign | x509.KeyUsageCRLSign, BasicConstraintsValid: true, MaxPathLen: 0, MaxPathLenZero: true, Issuer: root.Subject, Subject: pkix.Name{CommonName: "Smallstep Intermediate"}, SerialNumber: mustSerialNumber(), SubjectKeyId: mustSubjectKeyID(resp.PublicKey), } b, err = x509.CreateCertificate(rand.Reader, intermediate, root, resp.PublicKey, signer) if err != nil { return err } if err = utils.WriteFile("intermediate_ca.crt", pem.EncodeToMemory(&pem.Block{ Type: "CERTIFICATE", Bytes: b, }), 0600); err != nil { return err } ui.PrintSelected("Intermediate Key", resp.Name) ui.PrintSelected("Intermediate Certificate", "intermediate_ca.crt") return nil } func createSSH(c *awskms.KMS) error { ui.Println("Creating SSH Keys ...") // User Key resp, err := c.CreateKey(&apiv1.CreateKeyRequest{ Name: "ssh-user-key", SignatureAlgorithm: apiv1.ECDSAWithSHA256, }) if err != nil { return err } key, err := ssh.NewPublicKey(resp.PublicKey) if err != nil { return err } if err = utils.WriteFile("ssh_user_ca_key.pub", ssh.MarshalAuthorizedKey(key), 0600); err != nil { return err } ui.PrintSelected("SSH User Public Key", "ssh_user_ca_key.pub") ui.PrintSelected("SSH User Private Key", resp.Name) // Host Key resp, err = c.CreateKey(&apiv1.CreateKeyRequest{ Name: "ssh-host-key", SignatureAlgorithm: apiv1.ECDSAWithSHA256, }) if err != nil { return err } key, err = ssh.NewPublicKey(resp.PublicKey) if err != nil { return err } if err = utils.WriteFile("ssh_host_ca_key.pub", ssh.MarshalAuthorizedKey(key), 0600); err != nil { return err } ui.PrintSelected("SSH Host Public Key", "ssh_host_ca_key.pub") ui.PrintSelected("SSH Host Private Key", resp.Name) return nil } func mustSerialNumber() *big.Int { serialNumberLimit := new(big.Int).Lsh(big.NewInt(1), 128) sn, err := rand.Int(rand.Reader, serialNumberLimit) if err != nil { panic(err) } return sn } func mustSubjectKeyID(key crypto.PublicKey) []byte { b, err := x509.MarshalPKIXPublicKey(key) if err != nil { panic(err) } hash := sha1.Sum(b) return hash[:] }