/
driver.go
217 lines (195 loc) · 4.72 KB
/
driver.go
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package cmd
import (
"context"
"crypto/rand"
"errors"
"net"
"net/http"
"os"
"path/filepath"
"strings"
"time"
"github.com/cybozu-go/log"
sabakan "github.com/cybozu-go/sabakan/v2/client"
)
const maxRetry = 10
// Driver setup crypt devices.
type Driver struct {
serial string
sabakan *sabakan.Client
disks []Disk
cipher string
keySize int
tpmdev string
// status variables
tpmVersion TpmVersionID
}
// NewDriver creates Driver.
//
// It may return nil when the serial code of the machine cannot be identified,
// or sabakanURL is not valid.
func NewDriver(sabakanURL, cipher string, keySize int, tpmdev string, disks []Disk) (*Driver, error) {
hc := &http.Client{
Transport: &http.Transport{
DialContext: (&net.Dialer{
Timeout: 30 * time.Second,
KeepAlive: 30 * time.Second,
}).DialContext,
MaxIdleConns: 1,
IdleConnTimeout: 90 * time.Second,
TLSHandshakeTimeout: 10 * time.Second,
ExpectContinueTimeout: 1 * time.Second,
},
}
saba, err := sabakan.NewClient(sabakanURL, hc)
if err != nil {
return nil, err
}
data, err := os.ReadFile("/sys/devices/virtual/dmi/id/product_serial")
if err != nil {
return nil, err
}
serial := strings.TrimSpace(string(data))
return &Driver{
serial: serial,
sabakan: saba,
disks: disks,
cipher: cipher,
keySize: keySize,
tpmdev: tpmdev,
tpmVersion: TpmNone,
}, nil
}
// Setup setup crypt devices.
func (d *Driver) Setup(ctx context.Context) error {
var kek []byte
_, err := os.Stat(d.tpmdev)
switch {
case err == nil:
log.Info("TPM is found. disk encryption proceeds with TPM", map[string]interface{}{
"device": d.tpmdev,
})
kek, d.tpmVersion, err = readKeyFromTPM(d.tpmdev)
if err != nil {
return err
}
case os.IsNotExist(err):
log.Info("no TPM is found. disk encryption proceeds without TPM", map[string]interface{}{
"device": d.tpmdev,
log.FnError: err,
})
default:
return err
}
for _, disk := range d.disks {
err := d.setupDisk(ctx, disk, kek)
if err != nil {
return err
}
log.Info("encrypted disk is ready", map[string]interface{}{
"path": filepath.Join("/dev/mapper", disk.CryptName()),
})
}
return nil
}
func (d *Driver) setupDisk(ctx context.Context, disk Disk, tpmKek []byte) error {
log.Info("setting up full disk encryption", map[string]interface{}{
"disk": disk.Name(),
"tpm_kek_length": len(tpmKek),
})
f, err := os.OpenFile(disk.Device(), os.O_RDWR, 0660)
if err != nil {
return err
}
defer f.Close()
md, err := ReadMetadata(f)
if err == ErrNotFound {
log.Info("disk is not formatted. format disk", map[string]interface{}{
"disk": disk.Name(),
})
return d.formatDisk(ctx, disk, f, tpmKek)
}
if err != nil {
return err
}
if md.tpmVersion != d.tpmVersion {
if d.tpmVersion == 0 {
log.Error("TPM becomes unavailable", map[string]interface{}{
"tpmversion": md.tpmVersion.String(),
})
return errors.New("TPM unavailable")
}
log.Info("reformat disk because TPM is now available", map[string]interface{}{
"disk": disk.Name(),
"tpmversion": d.tpmVersion.String(),
})
return d.formatDisk(ctx, disk, f, tpmKek)
}
var retries int
RETRY:
ek, err := d.sabakan.CryptsGet(ctx, d.serial, md.HexID())
if err == nil {
log.Info("encryption key is found. run cryptsetup", map[string]interface{}{
"disk": disk.Name(),
})
return Cryptsetup(disk, md, ek, tpmKek)
}
if sabakan.IsNotFound(err) {
log.Info("encryption key is not found in sabakan. format disk", map[string]interface{}{
"disk": disk.Name(),
})
return d.formatDisk(ctx, disk, f, tpmKek)
}
log.Error("failed to retrieve key from sabakan", map[string]interface{}{
log.FnError: err,
"disk": disk.Name(),
"try": retries + 1,
})
if retries == maxRetry {
return err
}
retries++
time.Sleep(time.Duration(retries) * time.Second * 2)
goto RETRY
}
func (d *Driver) formatDisk(ctx context.Context, disk Disk, f *os.File, tpmKek []byte) error {
md, err := NewMetadata(d.cipher, d.keySize, d.tpmVersion)
if err != nil {
return err
}
key := make([]byte, d.keySize)
_, err = rand.Read(key)
if err != nil {
return err
}
ek, err := md.EncryptKey(key, tpmKek)
if err != nil {
return err
}
err = Cryptsetup(disk, md, ek, tpmKek)
if err != nil {
return err
}
// write metadata before sending ek to sabakan.
err = md.Write(f)
if err != nil {
return err
}
var retries int
RETRY:
err = d.sabakan.CryptsPut(ctx, d.serial, md.HexID(), ek)
if err == nil {
return nil
}
log.Error("failed to send key to sabakan", map[string]interface{}{
log.FnError: err,
"disk": disk.Name(),
"try": retries + 1,
})
if retries == maxRetry {
return err
}
retries++
time.Sleep(time.Duration(retries) * time.Second * 2)
goto RETRY
}