/
cryptsetup.go
56 lines (49 loc) · 1.38 KB
/
cryptsetup.go
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package cmd
import (
"bytes"
"os"
"os/exec"
"strconv"
"github.com/cybozu-go/log"
)
const (
modprobeCmd = "/sbin/modprobe"
cryptsetupCmd = "/sbin/cryptsetup"
)
// InitModules load kernel modules for dm-crypt.
func InitModules() {
err := exec.Command(modprobeCmd, "aesni-intel").Run()
if err == nil {
return
}
err = exec.Command(modprobeCmd, "aes-x86_64").Run()
if err == nil {
return
}
log.Warn("failed to load AES kernel modules", nil)
}
// Cryptsetup invokes cryptsetup to open crypt device.
// ek is the encrypted encryption key.
func Cryptsetup(d Disk, md *Metadata, ek, tpmKek []byte) error {
key, err := md.DecryptKey(ek, tpmKek)
if err != nil {
return err
}
args := []string{
"--hash=plain", "--key-file=-", "--cipher=" + md.Cipher(),
"--key-size=" + strconv.Itoa(len(key)*8),
"--offset=" + strconv.Itoa(metadataSize/512),
// cryptsetup 2.0.0 and Linux 4.12 adds suport for larger sector sizes > 512.
// https://www.saout.de/pipermail/dm-crypt/2017-December/005771.html
// https://gitlab.com/cryptsetup/cryptsetup/wikis/DMCrypt
//"--sector-size=" + strconv.Itoa(d.SectorSize()),
"--allow-discards",
"--perf-no_read_workqueue", "--perf-no_write_workqueue",
"open", "--type=plain", d.Device(), d.CryptName(),
}
cmd := exec.Command(cryptsetupCmd, args...)
cmd.Stdout = os.Stdout
cmd.Stderr = os.Stderr
cmd.Stdin = bytes.NewReader(key)
return cmd.Run()
}