mirror of
https://github.com/google/go-attestation.git
synced 2024-12-24 07:06:45 +00:00
103 lines
2.4 KiB
Go
103 lines
2.4 KiB
Go
package main
|
|
|
|
import (
|
|
"crypto/rand"
|
|
"crypto/rsa"
|
|
"crypto/x509"
|
|
"crypto/x509/pkix"
|
|
"encoding/binary"
|
|
"encoding/hex"
|
|
"flag"
|
|
"fmt"
|
|
"math/big"
|
|
"os"
|
|
"os/exec"
|
|
"strings"
|
|
"time"
|
|
)
|
|
|
|
func ekPub() *rsa.PublicKey {
|
|
out, err := exec.Command("tpm_getpubek", "-z").Output()
|
|
if err != nil {
|
|
fmt.Fprintf(os.Stderr, "Error: %v\n", err)
|
|
os.Exit(1)
|
|
}
|
|
|
|
spl := strings.Split(string(out), "Public Key:")
|
|
hexKey := strings.NewReplacer(" ", "", "\n", "", "\r", "", "\t", "").Replace(spl[1])
|
|
|
|
modBytes, err := hex.DecodeString(hexKey)
|
|
if err != nil {
|
|
fmt.Fprintf(os.Stderr, "Error: %v\n", err)
|
|
os.Exit(1)
|
|
}
|
|
return &rsa.PublicKey{
|
|
N: new(big.Int).SetBytes(modBytes),
|
|
E: 65537,
|
|
}
|
|
}
|
|
|
|
func generateCertificate(pub *rsa.PublicKey) []byte {
|
|
priv, err := rsa.GenerateKey(rand.Reader, 2048)
|
|
if err != nil {
|
|
fmt.Fprintf(os.Stderr, "Error: %v\n", err)
|
|
os.Exit(1)
|
|
}
|
|
|
|
serialNumberLimit := new(big.Int).Lsh(big.NewInt(1), 128)
|
|
serialNumber, err := rand.Int(rand.Reader, serialNumberLimit)
|
|
if err != nil {
|
|
fmt.Fprintf(os.Stderr, "Error: %v\n", err)
|
|
os.Exit(1)
|
|
}
|
|
|
|
template := x509.Certificate{
|
|
SerialNumber: serialNumber,
|
|
Subject: pkix.Name{
|
|
Organization: []string{"Acme Co"},
|
|
},
|
|
NotBefore: time.Now(),
|
|
NotAfter: time.Now().AddDate(1, 0, 0),
|
|
KeyUsage: x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature,
|
|
ExtKeyUsage: []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth},
|
|
BasicConstraintsValid: true,
|
|
}
|
|
|
|
derBytes, err := x509.CreateCertificate(rand.Reader, &template, &template, pub, priv)
|
|
if err != nil {
|
|
fmt.Fprintf(os.Stderr, "Error: %v\n", err)
|
|
os.Exit(1)
|
|
}
|
|
return derBytes
|
|
}
|
|
|
|
func main() {
|
|
flag.Parse()
|
|
certBytes := generateCertificate(ekPub())
|
|
|
|
f, err := os.OpenFile("/tmp/ekcert", os.O_RDWR|os.O_TRUNC|os.O_CREATE, 0755)
|
|
if err != nil {
|
|
fmt.Fprintf(os.Stderr, "Error: %v\n", err)
|
|
os.Exit(1)
|
|
}
|
|
|
|
// Write the header as documented in: TCG PC Specific Implementation
|
|
// Specification, section 7.3.2.
|
|
f.Write([]byte{0x10, 0x01, 0x00})
|
|
certLength := make([]byte, 2)
|
|
binary.BigEndian.PutUint16(certLength, uint16(len(certBytes)))
|
|
f.Write(certLength)
|
|
|
|
f.Write(certBytes)
|
|
f.Close()
|
|
|
|
cmd := exec.Command("tpm_nvwrite", "-z", "-i", "268496896", "-f", "/tmp/ekcert")
|
|
cmd.Stdout = os.Stdout
|
|
cmd.Stderr = os.Stderr
|
|
if err := cmd.Run(); err != nil {
|
|
fmt.Fprintf(os.Stderr, "Error: %v\n", err)
|
|
os.Exit(1)
|
|
}
|
|
|
|
}
|