libgocryptfs/masterkey.go

66 lines
1.9 KiB
Go

package main
import (
"encoding/hex"
"os"
"strings"
"golang.org/x/crypto/ssh/terminal"
"github.com/rfjakob/gocryptfs/internal/cryptocore"
"github.com/rfjakob/gocryptfs/internal/exitcodes"
"github.com/rfjakob/gocryptfs/internal/tlog"
)
// printMasterKey - remind the user that he should store the master key in
// a safe place
func printMasterKey(key []byte) {
if !terminal.IsTerminal(int(os.Stdout.Fd())) {
// We don't want the master key to end up in a log file
tlog.Info.Printf("Not running on a terminal, suppressing master key display\n")
return
}
h := hex.EncodeToString(key)
var hChunked string
// Try to make it less scary by splitting it up in chunks
for i := 0; i < len(h); i += 8 {
hChunked += h[i : i+8]
if i < 52 {
hChunked += "-"
}
if i == 24 {
hChunked += "\n "
}
}
tlog.Info.Printf(`
Your master key is:
%s
If the gocryptfs.conf file becomes corrupted or you ever forget your password,
there is only one hope for recovery: The master key. Print it to a piece of
paper and store it in a drawer. Use "-q" to suppress this message.
`, tlog.ColorGrey+hChunked+tlog.ColorReset)
}
// parseMasterKey - Parse a hex-encoded master key that was passed on the command line
// Calls os.Exit on failure
func parseMasterKey(masterkey string) []byte {
masterkey = strings.Replace(masterkey, "-", "", -1)
key, err := hex.DecodeString(masterkey)
if err != nil {
tlog.Fatal.Printf("Could not parse master key: %v", err)
os.Exit(exitcodes.MasterKey)
}
if len(key) != cryptocore.KeyLen {
tlog.Fatal.Printf("Master key has length %d but we require length %d", len(key), cryptocore.KeyLen)
os.Exit(exitcodes.MasterKey)
}
tlog.Info.Printf("Using explicit master key.")
tlog.Info.Printf(tlog.ColorYellow +
"THE MASTER KEY IS VISIBLE VIA \"ps ax\" AND MAY BE STORED IN YOUR SHELL HISTORY!\n" +
"ONLY USE THIS MODE FOR EMERGENCIES." + tlog.ColorReset)
return key
}