/
utilities.go
54 lines (46 loc) · 1.29 KB
/
utilities.go
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//go:build linux
// +build linux
package crypt
import (
"bytes"
"crypto/rand"
"fmt"
"io"
"os"
)
func zeroFirstBlock(path string, blockSize int) error {
fout, err := os.OpenFile(path, os.O_WRONLY, 0)
if err != nil {
return fmt.Errorf("failed to open file for zero'ing: %w", err)
}
defer fout.Close()
size, err := fout.Seek(0, io.SeekEnd)
if err != nil {
return fmt.Errorf("error seeking end of %s: %w", path, err)
}
if size < int64(blockSize) {
return fmt.Errorf("file size is smaller than minimum expected: %d < %d", size, blockSize)
}
_, err = fout.Seek(0, io.SeekStart)
if err != nil {
return fmt.Errorf("error seeking start of %s: %w", path, err)
}
zeros := bytes.Repeat([]byte{0}, blockSize)
if _, err := fout.Write(zeros); err != nil {
return fmt.Errorf("failed to zero-out bytes: %w", err)
}
return nil
}
// generateKeyFile generates a file with random values.
func generateKeyFile(path string, size int64) error {
// The crypto.rand interface generates random numbers using /dev/urandom
keyArray := make([]byte, size)
_, err := rand.Read(keyArray[:])
if err != nil {
return fmt.Errorf("failed to generate key slice: %w", err)
}
if err := os.WriteFile(path, keyArray[:], 0644); err != nil {
return fmt.Errorf("failed to save key to file: %w", err)
}
return nil
}