113 lines
3.5 KiB
Go
113 lines
3.5 KiB
Go
package main
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import (
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"encoding/hex"
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"os"
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"strings"
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"golang.org/x/crypto/ssh/terminal"
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"github.com/rfjakob/gocryptfs/internal/configfile"
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"github.com/rfjakob/gocryptfs/internal/cryptocore"
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"github.com/rfjakob/gocryptfs/internal/exitcodes"
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"github.com/rfjakob/gocryptfs/internal/readpassword"
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"github.com/rfjakob/gocryptfs/internal/tlog"
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)
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// printMasterKey - remind the user that he should store the master key in
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// a safe place
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func printMasterKey(key []byte) {
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if !terminal.IsTerminal(int(os.Stdout.Fd())) {
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// We don't want the master key to end up in a log file
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tlog.Info.Printf("Not running on a terminal, suppressing master key display\n")
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return
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}
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h := hex.EncodeToString(key)
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var hChunked string
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// Try to make it less scary by splitting it up in chunks
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for i := 0; i < len(h); i += 8 {
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hChunked += h[i : i+8]
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if i < 52 {
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hChunked += "-"
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}
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if i == 24 {
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hChunked += "\n "
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}
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}
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tlog.Info.Printf(`
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Your master key is:
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%s
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If the gocryptfs.conf file becomes corrupted or you ever forget your password,
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there is only one hope for recovery: The master key. Print it to a piece of
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paper and store it in a drawer. Use "-q" to suppress this message.
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`, tlog.ColorGrey+hChunked+tlog.ColorReset)
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}
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// parseMasterKey - Parse a hex-encoded master key that was passed on the command line
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// Calls os.Exit on failure
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func parseMasterKey(masterkey string, fromStdin bool) []byte {
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masterkey = strings.Replace(masterkey, "-", "", -1)
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key, err := hex.DecodeString(masterkey)
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if err != nil {
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tlog.Fatal.Printf("Could not parse master key: %v", err)
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os.Exit(exitcodes.MasterKey)
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}
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if len(key) != cryptocore.KeyLen {
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tlog.Fatal.Printf("Master key has length %d but we require length %d", len(key), cryptocore.KeyLen)
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os.Exit(exitcodes.MasterKey)
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}
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tlog.Info.Printf("Using explicit master key.")
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if !fromStdin {
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tlog.Info.Printf(tlog.ColorYellow +
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"THE MASTER KEY IS VISIBLE VIA \"ps ax\" AND MAY BE STORED IN YOUR SHELL HISTORY!\n" +
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"ONLY USE THIS MODE FOR EMERGENCIES" + tlog.ColorReset)
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}
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return key
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}
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// getMasterKey looks at "args" to determine where the master key should come
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// from (-masterkey=a-b-c-d or stdin or from the config file).
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// If it comes from the config file, the user is prompted for the password
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// and a ConfFile instance is returned.
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// Calls os.Exit on failure.
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func getMasterKey(args *argContainer) (masterkey []byte, confFile *configfile.ConfFile) {
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masterkeyFromStdin := false
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// "-masterkey=stdin"
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if args.masterkey == "stdin" {
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args.masterkey = string(readpassword.Once("", "Masterkey"))
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masterkeyFromStdin = true
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}
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// "-masterkey=941a6029-3adc6a1c-..."
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if args.masterkey != "" {
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return parseMasterKey(args.masterkey, masterkeyFromStdin), nil
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}
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// "-zerokey"
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if args.zerokey {
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tlog.Info.Printf("Using all-zero dummy master key.")
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tlog.Info.Printf(tlog.ColorYellow +
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"ZEROKEY MODE PROVIDES NO SECURITY AT ALL AND SHOULD ONLY BE USED FOR TESTING." +
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tlog.ColorReset)
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return make([]byte, cryptocore.KeyLen), nil
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}
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var err error
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// Load master key from config file (normal operation).
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// Prompts the user for the password.
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masterkey, confFile, err = loadConfig(args)
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if err != nil {
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if args._ctlsockFd != nil {
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// Close the socket file (which also deletes it)
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args._ctlsockFd.Close()
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}
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exitcodes.Exit(err)
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}
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readpassword.CheckTrailingGarbage()
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if !args.fsck {
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// We only want to print the masterkey message on a normal mount.
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printMasterKey(masterkey)
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}
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return masterkey, confFile
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}
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