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refactor: extract secure boot certificate generation
Fixes siderolabs#7412 Signed-off-by: Andrey Smirnov <andrey.smirnov@talos-systems.com>
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,229 @@ | ||
| // This Source Code Form is subject to the terms of the Mozilla Public | ||
| // License, v. 2.0. If a copy of the MPL was not distributed with this | ||
| // file, You can obtain one at http://mozilla.org/MPL/2.0/. | ||
|
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||
| package gen | ||
|
|
||
| import ( | ||
| "fmt" | ||
| "io/fs" | ||
| "os" | ||
| "path/filepath" | ||
| "time" | ||
|
|
||
| "github.com/foxboron/go-uefi/efi" | ||
| "github.com/foxboron/go-uefi/efi/signature" | ||
| "github.com/foxboron/go-uefi/efi/util" | ||
| "github.com/google/uuid" | ||
| "github.com/siderolabs/crypto/x509" | ||
| "github.com/spf13/cobra" | ||
|
|
||
| "github.com/siderolabs/talos/pkg/machinery/config/generate/secrets" | ||
| ) | ||
|
|
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| var genSecurebootCmdFlags struct { | ||
| outputDirectory string | ||
| } | ||
|
|
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| // genSecurebootCmd represents the `gen secureboot` command. | ||
| var genSecurebootCmd = &cobra.Command{ | ||
| Use: "secureboot", | ||
| Short: "Generates secrets for the SecureBoot process", | ||
| Long: ``, | ||
| } | ||
|
|
||
| var genSecurebootUKICmdFlags struct { | ||
| commonName string | ||
| } | ||
|
|
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| // genSecurebootUKICmd represents the `gen secureboot uki` command. | ||
| var genSecurebootUKICmd = &cobra.Command{ | ||
| Use: "uki", | ||
| Short: "Generates a certificate which is used to sign boot assets (UKI)", | ||
| Long: ``, | ||
| Args: cobra.NoArgs, | ||
| RunE: func(cmd *cobra.Command, args []string) error { | ||
| return generateSigningCerts(genSecurebootCmdFlags.outputDirectory, "uki", genSecurebootUKICmdFlags.commonName, 4096) | ||
| }, | ||
| } | ||
|
|
||
| var genSecurebootPCRCmdFlags struct { | ||
| commonName string | ||
| } | ||
|
|
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| // genSecurebootPCRCmd represents the `gen secureboot pcr` command. | ||
| var genSecurebootPCRCmd = &cobra.Command{ | ||
| Use: "pcr", | ||
| Short: "Generates a certificate which is used to sign TPM PCR values", | ||
| Long: ``, | ||
| Args: cobra.NoArgs, | ||
| RunE: func(cmd *cobra.Command, args []string) error { | ||
| return generateSigningCerts(genSecurebootCmdFlags.outputDirectory, "pcr", genSecurebootPCRCmdFlags.commonName, 2048) | ||
| }, | ||
| } | ||
|
|
||
| var genSecurebootDatabaseCmdFlags struct { | ||
| enrolledCertificatePath string | ||
| signingCertificatePath, signingKeyPath string | ||
| } | ||
|
|
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| // genSecurebootDatabaseCmd represents the `gen secureboot database` command. | ||
| var genSecurebootDatabaseCmd = &cobra.Command{ | ||
| Use: "database", | ||
| Short: "Generates a UEFI database to enroll the signing certificate", | ||
| Long: ``, | ||
| Args: cobra.NoArgs, | ||
| RunE: func(cmd *cobra.Command, args []string) error { | ||
| return generateSecureBootDatabase( | ||
| genSecurebootCmdFlags.outputDirectory, | ||
| genSecurebootDatabaseCmdFlags.enrolledCertificatePath, | ||
| genSecurebootDatabaseCmdFlags.signingKeyPath, | ||
| genSecurebootDatabaseCmdFlags.signingCertificatePath, | ||
| ) | ||
| }, | ||
| } | ||
|
|
||
| func checkedWrite(path string, data []byte, perm fs.FileMode) error { //nolint:unparam | ||
| if err := validateFileExists(path); err != nil { | ||
| return err | ||
| } | ||
|
|
||
| if dirname := filepath.Dir(path); dirname != "." { | ||
| if err := os.MkdirAll(dirname, 0o700); err != nil { | ||
| return err | ||
| } | ||
| } | ||
|
|
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| fmt.Fprintf(os.Stderr, "writing %s\n", path) | ||
|
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| return os.WriteFile(path, data, perm) | ||
| } | ||
|
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| func generateSigningCerts(path, prefix, commonName string, rsaBits int) error { | ||
| currentTime := time.Now() | ||
|
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| opts := []x509.Option{ | ||
| x509.RSA(true), | ||
| x509.Bits(rsaBits), | ||
| x509.CommonName(commonName), | ||
| x509.NotAfter(currentTime.Add(secrets.CAValidityTime)), | ||
| x509.NotBefore(currentTime), | ||
| x509.Organization(commonName), | ||
| } | ||
|
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| signingKey, err := x509.NewSelfSignedCertificateAuthority(opts...) | ||
| if err != nil { | ||
| return err | ||
| } | ||
|
|
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| if err = checkedWrite(filepath.Join(path, prefix+"-signing-cert.pem"), signingKey.CrtPEM, 0o600); err != nil { | ||
| return err | ||
| } | ||
|
|
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| if err = checkedWrite(filepath.Join(path, prefix+"-signing-key.pem"), signingKey.KeyPEM, 0o600); err != nil { | ||
| return err | ||
| } | ||
|
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| pemKey := x509.PEMEncodedKey{ | ||
| Key: signingKey.KeyPEM, | ||
| } | ||
|
|
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| privKey, err := pemKey.GetRSAKey() | ||
| if err != nil { | ||
| return err | ||
| } | ||
|
|
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| return checkedWrite(filepath.Join(path, prefix+"-signing-public-key.pem"), privKey.PublicKeyPEM, 0o600) | ||
| } | ||
|
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| // generateSecureBootDatabase generates a UEFI database to enroll the signing certificate. | ||
| // | ||
| // ref: https://blog.hansenpartnership.com/the-meaning-of-all-the-uefi-keys/ | ||
| // | ||
| //nolint:gocyclo | ||
| func generateSecureBootDatabase(path, enrolledCertificatePath, signingKeyPath, signingCertificatePath string) error { | ||
| uuid, err := uuid.NewRandom() | ||
| if err != nil { | ||
| return err | ||
| } | ||
|
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| efiGUID := util.StringToGUID(uuid.String()) | ||
|
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| // Reuse the generated test signing key for secure boot | ||
| signingPEM, err := x509.NewCertificateAndKeyFromFiles(signingCertificatePath, signingKeyPath) | ||
| if err != nil { | ||
| return err | ||
| } | ||
|
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| cert, err := signingPEM.GetCert() | ||
| if err != nil { | ||
| return err | ||
| } | ||
|
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| key, err := signingPEM.GetRSAKey() | ||
| if err != nil { | ||
| return err | ||
| } | ||
|
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| enrolledPEM, err := os.ReadFile(enrolledCertificatePath) | ||
| if err != nil { | ||
| return err | ||
| } | ||
|
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| // Create ESL | ||
| db := signature.NewSignatureDatabase() | ||
| if err = db.Append(signature.CERT_X509_GUID, *efiGUID, enrolledPEM); err != nil { | ||
| return err | ||
| } | ||
|
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| // Sign the ESL, but for each EFI variable | ||
| signedDB, err := efi.SignEFIVariable(key, cert, "db", db.Bytes()) | ||
| if err != nil { | ||
| return err | ||
| } | ||
|
|
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| signedKEK, err := efi.SignEFIVariable(key, cert, "KEK", db.Bytes()) | ||
| if err != nil { | ||
| return err | ||
| } | ||
|
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| signedPK, err := efi.SignEFIVariable(key, cert, "PK", db.Bytes()) | ||
| if err != nil { | ||
| return err | ||
| } | ||
|
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| // output all files with sd-boot conventional names for auto-enrolment | ||
| for _, out := range []struct { | ||
| name string | ||
| data []byte | ||
| }{ | ||
| {"db.auth", signedDB}, | ||
| {"KEK.auth", signedKEK}, | ||
| {"PK.auth", signedPK}, | ||
| } { | ||
| if err = checkedWrite(filepath.Join(path, out.name), out.data, 0o600); err != nil { | ||
| return err | ||
| } | ||
| } | ||
|
|
||
| return nil | ||
| } | ||
|
|
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| func init() { | ||
| genSecurebootCmd.PersistentFlags().StringVarP(&genSecurebootCmdFlags.outputDirectory, "output", "o", "_out", "path to the directory storing the generated files") | ||
| Cmd.AddCommand(genSecurebootCmd) | ||
|
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| genSecurebootUKICmd.Flags().StringVar(&genSecurebootUKICmdFlags.commonName, "common-name", "Test UKI Signing Key", "common name for the certificate") | ||
| genSecurebootCmd.AddCommand(genSecurebootUKICmd) | ||
|
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| genSecurebootPCRCmd.Flags().StringVar(&genSecurebootPCRCmdFlags.commonName, "common-name", "Test PCR Signing Key", "common name for the certificate") | ||
| genSecurebootCmd.AddCommand(genSecurebootPCRCmd) | ||
|
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| genSecurebootDatabaseCmd.Flags().StringVar( | ||
| &genSecurebootDatabaseCmdFlags.enrolledCertificatePath, "enrolled-certificate", "_out/uki-signing-cert.pem", "path to the certificate to enroll") | ||
| genSecurebootDatabaseCmd.Flags().StringVar( | ||
| &genSecurebootDatabaseCmdFlags.signingCertificatePath, "signing-certificate", "_out/uki-signing-cert.pem", "path to the certificate used to sign the database") | ||
| genSecurebootDatabaseCmd.Flags().StringVar( | ||
| &genSecurebootDatabaseCmdFlags.signingKeyPath, "signing-key", "_out/uki-signing-key.pem", "path to the key used to sign the database") | ||
| genSecurebootCmd.AddCommand(genSecurebootDatabaseCmd) | ||
| } |
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