package main import ( "encoding/hex" "flag" "fmt" "io" "os" "runtime" "github.com/rfjakob/gocryptfs/v2/internal/configfile" "github.com/rfjakob/gocryptfs/v2/internal/contentenc" "github.com/rfjakob/gocryptfs/v2/internal/cryptocore" "github.com/rfjakob/gocryptfs/v2/internal/exitcodes" "github.com/rfjakob/gocryptfs/v2/internal/fido2" "github.com/rfjakob/gocryptfs/v2/internal/readpassword" "github.com/rfjakob/gocryptfs/v2/internal/tlog" ) // GitVersion is the gocryptfs version according to git, set by build.bash var GitVersion = "[GitVersion not set - please compile using ./build.bash]" // BuildDate is a date string like "2017-09-06", set by build.bash var BuildDate = "0000-00-00" const ( myName = "gocryptfs-xray" ) // blockSize is the ciphertext block size including overheads func blockSize(alg cryptocore.AEADTypeEnum) int { return alg.NonceSize + contentenc.DefaultBS + cryptocore.AuthTagLen } func errExit(err error) { fmt.Println(err) os.Exit(1) } func prettyPrintHeader(h *contentenc.FileHeader, algo cryptocore.AEADTypeEnum) { id := hex.EncodeToString(h.ID) fmt.Printf("Header: Version: %d, Id: %s, assuming %s mode\n", h.Version, id, algo.Name) } // printVersion prints a version string like this: // gocryptfs v1.7-32-gcf99cfd; go-fuse v1.0.0-174-g22a9cb9; 2019-05-12 go1.12 linux/amd64 func printVersion() { built := fmt.Sprintf("%s %s", BuildDate, runtime.Version()) fmt.Printf("%s %s; %s %s/%s\n", myName, GitVersion, built, runtime.GOOS, runtime.GOARCH) } func usage() { printVersion() fmt.Printf("\n") fmt.Fprintf(os.Stderr, "Usage: %s [OPTIONS] FILE\n"+ "\n"+ "Options:\n", myName) flag.PrintDefaults() fmt.Fprintf(os.Stderr, "\n"+ "Examples:\n"+ " gocryptfs-xray myfs/mCXnISiv7nEmyc0glGuhTQ\n"+ " gocryptfs-xray -dumpmasterkey myfs/gocryptfs.conf\n"+ " gocryptfs-xray -encrypt-paths myfs.sock\n") } // sum counts the number of true values func sum(x ...*bool) (s int) { for _, v := range x { if *v { s++ } } return s } type argContainer struct { dumpmasterkey *bool decryptPaths *bool encryptPaths *bool aessiv *bool xchacha *bool sep0 *bool fido2 *string version *bool } func main() { var args argContainer args.dumpmasterkey = flag.Bool("dumpmasterkey", false, "Decrypt and dump the master key") args.decryptPaths = flag.Bool("decrypt-paths", false, "Decrypt file paths using gocryptfs control socket") args.encryptPaths = flag.Bool("encrypt-paths", false, "Encrypt file paths using gocryptfs control socket") args.sep0 = flag.Bool("0", false, "Use \\0 instead of \\n as separator") args.aessiv = flag.Bool("aessiv", false, "Assume AES-SIV mode instead of AES-GCM") args.xchacha = flag.Bool("xchacha", false, "Assume XChaCha20-Poly1305 mode instead of AES-GCM") args.fido2 = flag.String("fido2", "", "Protect the masterkey using a FIDO2 token instead of a password") args.version = flag.Bool("version", false, "Print version information") flag.Usage = usage flag.Parse() if *args.version { printVersion() os.Exit(0) } s := sum(args.dumpmasterkey, args.decryptPaths, args.encryptPaths) if s > 1 { fmt.Printf("fatal: %d operations were requested\n", s) os.Exit(1) } if flag.NArg() != 1 { usage() os.Exit(1) } fn := flag.Arg(0) if *args.decryptPaths { decryptPaths(fn, *args.sep0) } if *args.encryptPaths { encryptPaths(fn, *args.sep0) } f, err := os.Open(fn) if err != nil { errExit(err) } defer f.Close() if *args.dumpmasterkey { dumpMasterKey(fn, *args.fido2) } else { inspectCiphertext(&args, f) } } func dumpMasterKey(fn string, fido2Path string) { tlog.Info.Enabled = false cf, err := configfile.Load(fn) if err != nil { fmt.Fprintln(os.Stderr, err) exitcodes.Exit(err) } var pw []byte if cf.IsFeatureFlagSet(configfile.FlagFIDO2) { if fido2Path == "" { tlog.Fatal.Printf("Masterkey encrypted using FIDO2 token; need to use the --fido2 option.") os.Exit(exitcodes.Usage) } pw = fido2.Secret(fido2Path, cf.FIDO2.CredentialID, cf.FIDO2.HMACSalt) } else { pw = readpassword.Once(nil, nil, "") } masterkey, err := cf.DecryptMasterKey(pw) // Purge password from memory for i := range pw { pw[i] = 0 } if err != nil { tlog.Fatal.Println(err) os.Exit(exitcodes.LoadConf) } fmt.Println(hex.EncodeToString(masterkey)) // Purge masterkey from memory for i := range masterkey { masterkey[i] = 0 } } func inspectCiphertext(args *argContainer, fd *os.File) { algo := cryptocore.BackendGoGCM if *args.aessiv { algo = cryptocore.BackendAESSIV } else if *args.xchacha { algo = cryptocore.BackendXChaCha20Poly1305 } headerBytes := make([]byte, contentenc.HeaderLen) n, err := fd.ReadAt(headerBytes, 0) if err == io.EOF && n == 0 { fmt.Println("empty file") os.Exit(0) } else if err == io.EOF { fmt.Printf("incomplete file header: read %d bytes, want %d\n", n, contentenc.HeaderLen) os.Exit(1) } else if err != nil { errExit(err) } header, err := contentenc.ParseHeader(headerBytes) if err != nil { errExit(err) } prettyPrintHeader(header, algo) var i int64 buf := make([]byte, blockSize(algo)) for i = 0; ; i++ { off := contentenc.HeaderLen + i*int64(blockSize(algo)) n, err := fd.ReadAt(buf, off) if err != nil && err != io.EOF { errExit(err) } if n == 0 && err == io.EOF { break } // A block contains at least the IV, the Auth Tag and 1 data byte if n < algo.NonceSize+cryptocore.AuthTagLen+1 { errExit(fmt.Errorf("corrupt block: truncated data, len=%d", n)) } data := buf[:n] // Parse block data iv := data[:algo.NonceSize] tag := data[len(data)-cryptocore.AuthTagLen:] if *args.aessiv { tag = data[algo.NonceSize : algo.NonceSize+cryptocore.AuthTagLen] } fmt.Printf("Block %2d: IV: %s, Tag: %s, Offset: %5d Len: %d\n", i, hex.EncodeToString(iv), hex.EncodeToString(tag), off, len(data)) } }