Re-design of the original gocryptfs code to work as a library.
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libgocryptfs/gocryptfs-xray/xray_main.go

218 lines
5.8 KiB

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) {
6 years ago
id := hex.EncodeToString(h.ID)
fmt.Printf("Header: Version: %d, Id: %s, assuming %s mode\n", h.Version, id, algo.Algo)
}
// 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)
Fix issues found by ineffassign gocryptfs$ ineffassign ./... /home/jakob/go/src/github.com/rfjakob/gocryptfs/internal/configfile/config_file.go:243:2: ineffectual assignment to scryptHash /home/jakob/go/src/github.com/rfjakob/gocryptfs/internal/configfile/config_file.go:272:2: ineffectual assignment to scryptHash /home/jakob/go/src/github.com/rfjakob/gocryptfs/internal/fusefrontend/file.go:285:3: ineffectual assignment to fileID /home/jakob/go/src/github.com/rfjakob/gocryptfs/internal/fusefrontend/node.go:367:3: ineffectual assignment to err /home/jakob/go/src/github.com/rfjakob/gocryptfs/internal/fusefrontend/node_open_create.go:68:2: ineffectual assignment to fd /home/jakob/go/src/github.com/rfjakob/gocryptfs/mount.go:308:2: ineffectual assignment to masterkey /home/jakob/go/src/github.com/rfjakob/gocryptfs/gocryptfs-xray/xray_main.go:156:13: ineffectual assignment to err /home/jakob/go/src/github.com/rfjakob/gocryptfs/internal/fusefrontend/prepare_syscall_test.go:65:16: ineffectual assignment to errno /home/jakob/go/src/github.com/rfjakob/gocryptfs/internal/syscallcompat/open_nofollow_test.go:34:2: ineffectual assignment to fd /home/jakob/go/src/github.com/rfjakob/gocryptfs/tests/defaults/acl_test.go:111:6: ineffectual assignment to err /home/jakob/go/src/github.com/rfjakob/gocryptfs/tests/defaults/acl_test.go:181:2: ineffectual assignment to sz /home/jakob/go/src/github.com/rfjakob/gocryptfs/tests/defaults/acl_test.go:198:2: ineffectual assignment to sz /home/jakob/go/src/github.com/rfjakob/gocryptfs/tests/defaults/main_test.go:365:8: ineffectual assignment to err /home/jakob/go/src/github.com/rfjakob/gocryptfs/tests/xattr/xattr_fd_test.go:30:6: ineffectual assignment to err /home/jakob/go/src/github.com/rfjakob/gocryptfs/tests/xattr/xattr_fd_test.go:66:6: ineffectual assignment to err
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// Purge password from memory
for i := range pw {
pw[i] = 0
}
Fix issues found by ineffassign gocryptfs$ ineffassign ./... /home/jakob/go/src/github.com/rfjakob/gocryptfs/internal/configfile/config_file.go:243:2: ineffectual assignment to scryptHash /home/jakob/go/src/github.com/rfjakob/gocryptfs/internal/configfile/config_file.go:272:2: ineffectual assignment to scryptHash /home/jakob/go/src/github.com/rfjakob/gocryptfs/internal/fusefrontend/file.go:285:3: ineffectual assignment to fileID /home/jakob/go/src/github.com/rfjakob/gocryptfs/internal/fusefrontend/node.go:367:3: ineffectual assignment to err /home/jakob/go/src/github.com/rfjakob/gocryptfs/internal/fusefrontend/node_open_create.go:68:2: ineffectual assignment to fd /home/jakob/go/src/github.com/rfjakob/gocryptfs/mount.go:308:2: ineffectual assignment to masterkey /home/jakob/go/src/github.com/rfjakob/gocryptfs/gocryptfs-xray/xray_main.go:156:13: ineffectual assignment to err /home/jakob/go/src/github.com/rfjakob/gocryptfs/internal/fusefrontend/prepare_syscall_test.go:65:16: ineffectual assignment to errno /home/jakob/go/src/github.com/rfjakob/gocryptfs/internal/syscallcompat/open_nofollow_test.go:34:2: ineffectual assignment to fd /home/jakob/go/src/github.com/rfjakob/gocryptfs/tests/defaults/acl_test.go:111:6: ineffectual assignment to err /home/jakob/go/src/github.com/rfjakob/gocryptfs/tests/defaults/acl_test.go:181:2: ineffectual assignment to sz /home/jakob/go/src/github.com/rfjakob/gocryptfs/tests/defaults/acl_test.go:198:2: ineffectual assignment to sz /home/jakob/go/src/github.com/rfjakob/gocryptfs/tests/defaults/main_test.go:365:8: ineffectual assignment to err /home/jakob/go/src/github.com/rfjakob/gocryptfs/tests/xattr/xattr_fd_test.go:30:6: ineffectual assignment to err /home/jakob/go/src/github.com/rfjakob/gocryptfs/tests/xattr/xattr_fd_test.go:66:6: ineffectual assignment to err
1 year ago
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
}
6 years ago
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 {
6 years ago
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))
xray: add support for inspecting AES-SIV files (-aessiv flag) https://github.com/rfjakob/gocryptfs/issues/299 : In GCM mode the auth tags are at the end of each block, but in SIV mode the auth tags follow immediately after the nonce. As a result, in AES-SIV mode the output of gocryptfs-xray is misleading and does not actually print the auth tag, but just the last 16-byte of the ciphertext. diff --git a/gocryptfs-xray/xray_main.go b/gocryptfs-xray/xray_main.go index 74c9fb3..5a81caf 100644 --- a/gocryptfs-xray/xray_main.go +++ b/gocryptfs-xray/xray_main.go @@ -16,9 +16,10 @@ import ( ) const ( - ivLen = contentenc.DefaultIVBits / 8 - blockSize = contentenc.DefaultBS + ivLen + cryptocore.AuthTagLen - myName = "gocryptfs-xray" + ivLen = contentenc.DefaultIVBits / 8 + authTagLen = cryptocore.AuthTagLen + blockSize = contentenc.DefaultBS + ivLen + cryptocore.AuthTagLen + myName = "gocryptfs-xray" ) func errExit(err error) { @@ -26,13 +27,18 @@ func errExit(err error) { os.Exit(1) } -func prettyPrintHeader(h *contentenc.FileHeader) { +func prettyPrintHeader(h *contentenc.FileHeader, aessiv bool) { id := hex.EncodeToString(h.ID) - fmt.Printf("Header: Version: %d, Id: %s\n", h.Version, id) + msg := "Header: Version: %d, Id: %s" + if aessiv { + msg += ", assuming AES-SIV mode" + } + fmt.Printf(msg+"\n", h.Version, id) } func main() { dumpmasterkey := flag.Bool("dumpmasterkey", false, "Decrypt and dump the master key") + aessiv := flag.Bool("aessiv", false, "Assume AES-SIV mode instead of AES-GCM") flag.Parse() if flag.NArg() != 1 { fmt.Fprintf(os.Stderr, "Usage: %s [OPTIONS] FILE\n"+ @@ -54,7 +60,7 @@ func main() { if *dumpmasterkey { dumpMasterKey(fn) } else { - inspectCiphertext(fd) + inspectCiphertext(fd, *aessiv) } } @@ -72,7 +78,7 @@ func dumpMasterKey(fn string) { } } -func inspectCiphertext(fd *os.File) { +func inspectCiphertext(fd *os.File, aessiv bool) { headerBytes := make([]byte, contentenc.HeaderLen) n, err := fd.ReadAt(headerBytes, 0) if err == io.EOF && n == 0 { @@ -88,34 +94,30 @@ func inspectCiphertext(fd *os.File) { if err != nil { errExit(err) } - prettyPrintHeader(header) + prettyPrintHeader(header, aessiv) var i int64 + buf := make([]byte, blockSize) for i = 0; ; i++ { - blockLen := int64(blockSize) off := contentenc.HeaderLen + i*blockSize - iv := make([]byte, ivLen) - _, err := fd.ReadAt(iv, off) - if err == io.EOF { - break - } else if err != nil { + n, err := fd.ReadAt(buf, off) + if err != nil && err != io.EOF { errExit(err) } - tag := make([]byte, cryptocore.AuthTagLen) - _, err = fd.ReadAt(tag, off+blockSize-cryptocore.AuthTagLen) - if err == io.EOF { - fi, err2 := fd.Stat() - if err2 != nil { - errExit(err2) - } - _, err2 = fd.ReadAt(tag, fi.Size()-cryptocore.AuthTagLen) - if err2 != nil { - errExit(err2) - } - blockLen = (fi.Size() - contentenc.HeaderLen) % blockSize - } else if err != nil { - 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 < ivLen+authTagLen+1 { + errExit(fmt.Errorf("corrupt block: truncated data, len=%d", n)) + } + data := buf[:n] + // Parse block data + iv := data[:ivLen] + tag := data[len(data)-authTagLen:] + if aessiv { + tag = data[ivLen : ivLen+authTagLen] } fmt.Printf("Block %2d: IV: %s, Tag: %s, Offset: %5d Len: %d\n", - i, hex.EncodeToString(iv), hex.EncodeToString(tag), off, blockLen) + i, hex.EncodeToString(iv), hex.EncodeToString(tag), off, len(data)) } } diff --git a/gocryptfs-xray/xray_tests/aessiv_fs.masterkey.txt b/gocryptfs-xray/xray_tests/aessiv_fs.masterkey.txt new file mode 100644 index 0000000..70835ac --- /dev/null +++ b/gocryptfs-xray/xray_tests/aessiv_fs.masterkey.txt @@ -0,0 +1,5 @@ +Your master key is: + + 29dd219d-e227ff20-8474469d-9fc9fdc6- + b434ab35-404e808c-489d441e-2c1003f2 + diff --git a/gocryptfs-xray/xray_tests/aessiv_fs.xray.txt b/gocryptfs-xray/xray_tests/aessiv_fs.xray.txt new file mode 100644 index 0000000..6a48079 --- /dev/null +++ b/gocryptfs-xray/xray_tests/aessiv_fs.xray.txt @@ -0,0 +1,3 @@ +Header: Version: 2, Id: c2f21142e108952a47edfe16053d2bb9, assuming AES-SIV mode +Block 0: IV: 7621fdc35be7671ac6f369214436e8ff, Tag: e8108c158b22cad6bb3296645357eb75, Offset: 18 Len: 4128 +Block 1: IV: f096d86a4dc3461ef17655cfcf865b13, Tag: 925f23d647e4ab7add2c8d36362cc5a9, Offset: 4146 Len: 936 diff --git a/gocryptfs-xray/xray_tests/aessiv_fs/Ldq-c4ADpM5iGSSrPjUAqQ b/gocryptfs-xray/xray_tests/aessiv_fs/Ldq-c4ADpM5iGSSrPjUAqQ new file mode 100644 index 0000000..bfd4dfe Binary files /dev/null and b/gocryptfs-xray/xray_tests/aessiv_fs/Ldq-c4ADpM5iGSSrPjUAqQ differ diff --git a/gocryptfs-xray/xray_tests/aessiv_fs/gocryptfs.conf b/gocryptfs-xray/xray_tests/aessiv_fs/gocryptfs.conf new file mode 100644 index 0000000..9b8b95f --- /dev/null +++ b/gocryptfs-xray/xray_tests/aessiv_fs/gocryptfs.conf @@ -0,0 +1,21 @@ +{ + "Creator": "gocryptfs v1.7-beta1-7-g6b94f5e", + "EncryptedKey": "D0kHfg/pryMO9Ydo15EwpYjNHf3iWKq2GJyNocbjwJt9blEeMoLD5DnoARuDzQs54hblw+9MHwFjCSHYmJrFbA==", + "ScryptObject": { + "Salt": "ehn0LM/Hy/4QkXAMCZq3c3p0O9G7gu5e3OQSR8MiJ6c=", + "N": 65536, + "R": 8, + "P": 1, + "KeyLen": 32 + }, + "Version": 2, + "FeatureFlags": [ + "GCMIV128", + "HKDF", + "DirIV", + "EMENames", + "LongNames", + "Raw64", + "AESSIV" + ] +} diff --git a/gocryptfs-xray/xray_tests/aessiv_fs/gocryptfs.diriv b/gocryptfs-xray/xray_tests/aessiv_fs/gocryptfs.diriv new file mode 100644 index 0000000..dd57ce1 --- /dev/null +++ b/gocryptfs-xray/xray_tests/aessiv_fs/gocryptfs.diriv @@ -0,0 +1 @@ +.¨Í1Aiõ&Á4—öÉ \ No newline at end of file diff --git a/gocryptfs-xray/xray_tests/xray_test.go b/gocryptfs-xray/xray_tests/xray_test.go index a3374b0..8e5fc0c 100644 --- a/gocryptfs-xray/xray_tests/xray_test.go +++ b/gocryptfs-xray/xray_tests/xray_test.go @@ -24,3 +24,20 @@ func TestAesgcmXray(t *testing.T) { fmt.Printf("have:\n%s", string(out)) } } + +func TestAessivXray(t *testing.T) { + expected, err := ioutil.ReadFile("aessiv_fs.xray.txt") + if err != nil { + t.Fatal(err) + } + cmd := exec.Command("../gocryptfs-xray", "-aessiv", "aessiv_fs/Ldq-c4ADpM5iGSSrPjUAqQ") + out, err := cmd.CombinedOutput() + if err != nil { + t.Fatal(err) + } + if bytes.Compare(out, expected) != 0 { + t.Errorf("Unexpected output") + fmt.Printf("expected:\n%s", string(expected)) + fmt.Printf("have:\n%s", string(out)) + } +}
4 years ago
n, err := fd.ReadAt(buf, off)
if err != nil && err != io.EOF {
errExit(err)
}
xray: add support for inspecting AES-SIV files (-aessiv flag) https://github.com/rfjakob/gocryptfs/issues/299 : In GCM mode the auth tags are at the end of each block, but in SIV mode the auth tags follow immediately after the nonce. As a result, in AES-SIV mode the output of gocryptfs-xray is misleading and does not actually print the auth tag, but just the last 16-byte of the ciphertext. diff --git a/gocryptfs-xray/xray_main.go b/gocryptfs-xray/xray_main.go index 74c9fb3..5a81caf 100644 --- a/gocryptfs-xray/xray_main.go +++ b/gocryptfs-xray/xray_main.go @@ -16,9 +16,10 @@ import ( ) const ( - ivLen = contentenc.DefaultIVBits / 8 - blockSize = contentenc.DefaultBS + ivLen + cryptocore.AuthTagLen - myName = "gocryptfs-xray" + ivLen = contentenc.DefaultIVBits / 8 + authTagLen = cryptocore.AuthTagLen + blockSize = contentenc.DefaultBS + ivLen + cryptocore.AuthTagLen + myName = "gocryptfs-xray" ) func errExit(err error) { @@ -26,13 +27,18 @@ func errExit(err error) { os.Exit(1) } -func prettyPrintHeader(h *contentenc.FileHeader) { +func prettyPrintHeader(h *contentenc.FileHeader, aessiv bool) { id := hex.EncodeToString(h.ID) - fmt.Printf("Header: Version: %d, Id: %s\n", h.Version, id) + msg := "Header: Version: %d, Id: %s" + if aessiv { + msg += ", assuming AES-SIV mode" + } + fmt.Printf(msg+"\n", h.Version, id) } func main() { dumpmasterkey := flag.Bool("dumpmasterkey", false, "Decrypt and dump the master key") + aessiv := flag.Bool("aessiv", false, "Assume AES-SIV mode instead of AES-GCM") flag.Parse() if flag.NArg() != 1 { fmt.Fprintf(os.Stderr, "Usage: %s [OPTIONS] FILE\n"+ @@ -54,7 +60,7 @@ func main() { if *dumpmasterkey { dumpMasterKey(fn) } else { - inspectCiphertext(fd) + inspectCiphertext(fd, *aessiv) } } @@ -72,7 +78,7 @@ func dumpMasterKey(fn string) { } } -func inspectCiphertext(fd *os.File) { +func inspectCiphertext(fd *os.File, aessiv bool) { headerBytes := make([]byte, contentenc.HeaderLen) n, err := fd.ReadAt(headerBytes, 0) if err == io.EOF && n == 0 { @@ -88,34 +94,30 @@ func inspectCiphertext(fd *os.File) { if err != nil { errExit(err) } - prettyPrintHeader(header) + prettyPrintHeader(header, aessiv) var i int64 + buf := make([]byte, blockSize) for i = 0; ; i++ { - blockLen := int64(blockSize) off := contentenc.HeaderLen + i*blockSize - iv := make([]byte, ivLen) - _, err := fd.ReadAt(iv, off) - if err == io.EOF { - break - } else if err != nil { + n, err := fd.ReadAt(buf, off) + if err != nil && err != io.EOF { errExit(err) } - tag := make([]byte, cryptocore.AuthTagLen) - _, err = fd.ReadAt(tag, off+blockSize-cryptocore.AuthTagLen) - if err == io.EOF { - fi, err2 := fd.Stat() - if err2 != nil { - errExit(err2) - } - _, err2 = fd.ReadAt(tag, fi.Size()-cryptocore.AuthTagLen) - if err2 != nil { - errExit(err2) - } - blockLen = (fi.Size() - contentenc.HeaderLen) % blockSize - } else if err != nil { - 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 < ivLen+authTagLen+1 { + errExit(fmt.Errorf("corrupt block: truncated data, len=%d", n)) + } + data := buf[:n] + // Parse block data + iv := data[:ivLen] + tag := data[len(data)-authTagLen:] + if aessiv { + tag = data[ivLen : ivLen+authTagLen] } fmt.Printf("Block %2d: IV: %s, Tag: %s, Offset: %5d Len: %d\n", - i, hex.EncodeToString(iv), hex.EncodeToString(tag), off, blockLen) + i, hex.EncodeToString(iv), hex.EncodeToString(tag), off, len(data)) } } diff --git a/gocryptfs-xray/xray_tests/aessiv_fs.masterkey.txt b/gocryptfs-xray/xray_tests/aessiv_fs.masterkey.txt new file mode 100644 index 0000000..70835ac --- /dev/null +++ b/gocryptfs-xray/xray_tests/aessiv_fs.masterkey.txt @@ -0,0 +1,5 @@ +Your master key is: + + 29dd219d-e227ff20-8474469d-9fc9fdc6- + b434ab35-404e808c-489d441e-2c1003f2 + diff --git a/gocryptfs-xray/xray_tests/aessiv_fs.xray.txt b/gocryptfs-xray/xray_tests/aessiv_fs.xray.txt new file mode 100644 index 0000000..6a48079 --- /dev/null +++ b/gocryptfs-xray/xray_tests/aessiv_fs.xray.txt @@ -0,0 +1,3 @@ +Header: Version: 2, Id: c2f21142e108952a47edfe16053d2bb9, assuming AES-SIV mode +Block 0: IV: 7621fdc35be7671ac6f369214436e8ff, Tag: e8108c158b22cad6bb3296645357eb75, Offset: 18 Len: 4128 +Block 1: IV: f096d86a4dc3461ef17655cfcf865b13, Tag: 925f23d647e4ab7add2c8d36362cc5a9, Offset: 4146 Len: 936 diff --git a/gocryptfs-xray/xray_tests/aessiv_fs/Ldq-c4ADpM5iGSSrPjUAqQ b/gocryptfs-xray/xray_tests/aessiv_fs/Ldq-c4ADpM5iGSSrPjUAqQ new file mode 100644 index 0000000..bfd4dfe Binary files /dev/null and b/gocryptfs-xray/xray_tests/aessiv_fs/Ldq-c4ADpM5iGSSrPjUAqQ differ diff --git a/gocryptfs-xray/xray_tests/aessiv_fs/gocryptfs.conf b/gocryptfs-xray/xray_tests/aessiv_fs/gocryptfs.conf new file mode 100644 index 0000000..9b8b95f --- /dev/null +++ b/gocryptfs-xray/xray_tests/aessiv_fs/gocryptfs.conf @@ -0,0 +1,21 @@ +{ + "Creator": "gocryptfs v1.7-beta1-7-g6b94f5e", + "EncryptedKey": "D0kHfg/pryMO9Ydo15EwpYjNHf3iWKq2GJyNocbjwJt9blEeMoLD5DnoARuDzQs54hblw+9MHwFjCSHYmJrFbA==", + "ScryptObject": { + "Salt": "ehn0LM/Hy/4QkXAMCZq3c3p0O9G7gu5e3OQSR8MiJ6c=", + "N": 65536, + "R": 8, + "P": 1, + "KeyLen": 32 + }, + "Version": 2, + "FeatureFlags": [ + "GCMIV128", + "HKDF", + "DirIV", + "EMENames", + "LongNames", + "Raw64", + "AESSIV" + ] +} diff --git a/gocryptfs-xray/xray_tests/aessiv_fs/gocryptfs.diriv b/gocryptfs-xray/xray_tests/aessiv_fs/gocryptfs.diriv new file mode 100644 index 0000000..dd57ce1 --- /dev/null +++ b/gocryptfs-xray/xray_tests/aessiv_fs/gocryptfs.diriv @@ -0,0 +1 @@ +.¨Í1Aiõ&Á4—öÉ \ No newline at end of file diff --git a/gocryptfs-xray/xray_tests/xray_test.go b/gocryptfs-xray/xray_tests/xray_test.go index a3374b0..8e5fc0c 100644 --- a/gocryptfs-xray/xray_tests/xray_test.go +++ b/gocryptfs-xray/xray_tests/xray_test.go @@ -24,3 +24,20 @@ func TestAesgcmXray(t *testing.T) { fmt.Printf("have:\n%s", string(out)) } } + +func TestAessivXray(t *testing.T) { + expected, err := ioutil.ReadFile("aessiv_fs.xray.txt") + if err != nil { + t.Fatal(err) + } + cmd := exec.Command("../gocryptfs-xray", "-aessiv", "aessiv_fs/Ldq-c4ADpM5iGSSrPjUAqQ") + out, err := cmd.CombinedOutput() + if err != nil { + t.Fatal(err) + } + if bytes.Compare(out, expected) != 0 { + t.Errorf("Unexpected output") + fmt.Printf("expected:\n%s", string(expected)) + fmt.Printf("have:\n%s", string(out)) + } +}
4 years ago
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 {
xray: add support for inspecting AES-SIV files (-aessiv flag) https://github.com/rfjakob/gocryptfs/issues/299 : In GCM mode the auth tags are at the end of each block, but in SIV mode the auth tags follow immediately after the nonce. As a result, in AES-SIV mode the output of gocryptfs-xray is misleading and does not actually print the auth tag, but just the last 16-byte of the ciphertext. diff --git a/gocryptfs-xray/xray_main.go b/gocryptfs-xray/xray_main.go index 74c9fb3..5a81caf 100644 --- a/gocryptfs-xray/xray_main.go +++ b/gocryptfs-xray/xray_main.go @@ -16,9 +16,10 @@ import ( ) const ( - ivLen = contentenc.DefaultIVBits / 8 - blockSize = contentenc.DefaultBS + ivLen + cryptocore.AuthTagLen - myName = "gocryptfs-xray" + ivLen = contentenc.DefaultIVBits / 8 + authTagLen = cryptocore.AuthTagLen + blockSize = contentenc.DefaultBS + ivLen + cryptocore.AuthTagLen + myName = "gocryptfs-xray" ) func errExit(err error) { @@ -26,13 +27,18 @@ func errExit(err error) { os.Exit(1) } -func prettyPrintHeader(h *contentenc.FileHeader) { +func prettyPrintHeader(h *contentenc.FileHeader, aessiv bool) { id := hex.EncodeToString(h.ID) - fmt.Printf("Header: Version: %d, Id: %s\n", h.Version, id) + msg := "Header: Version: %d, Id: %s" + if aessiv { + msg += ", assuming AES-SIV mode" + } + fmt.Printf(msg+"\n", h.Version, id) } func main() { dumpmasterkey := flag.Bool("dumpmasterkey", false, "Decrypt and dump the master key") + aessiv := flag.Bool("aessiv", false, "Assume AES-SIV mode instead of AES-GCM") flag.Parse() if flag.NArg() != 1 { fmt.Fprintf(os.Stderr, "Usage: %s [OPTIONS] FILE\n"+ @@ -54,7 +60,7 @@ func main() { if *dumpmasterkey { dumpMasterKey(fn) } else { - inspectCiphertext(fd) + inspectCiphertext(fd, *aessiv) } } @@ -72,7 +78,7 @@ func dumpMasterKey(fn string) { } } -func inspectCiphertext(fd *os.File) { +func inspectCiphertext(fd *os.File, aessiv bool) { headerBytes := make([]byte, contentenc.HeaderLen) n, err := fd.ReadAt(headerBytes, 0) if err == io.EOF && n == 0 { @@ -88,34 +94,30 @@ func inspectCiphertext(fd *os.File) { if err != nil { errExit(err) } - prettyPrintHeader(header) + prettyPrintHeader(header, aessiv) var i int64 + buf := make([]byte, blockSize) for i = 0; ; i++ { - blockLen := int64(blockSize) off := contentenc.HeaderLen + i*blockSize - iv := make([]byte, ivLen) - _, err := fd.ReadAt(iv, off) - if err == io.EOF { - break - } else if err != nil { + n, err := fd.ReadAt(buf, off) + if err != nil && err != io.EOF { errExit(err) } - tag := make([]byte, cryptocore.AuthTagLen) - _, err = fd.ReadAt(tag, off+blockSize-cryptocore.AuthTagLen) - if err == io.EOF { - fi, err2 := fd.Stat() - if err2 != nil { - errExit(err2) - } - _, err2 = fd.ReadAt(tag, fi.Size()-cryptocore.AuthTagLen) - if err2 != nil { - errExit(err2) - } - blockLen = (fi.Size() - contentenc.HeaderLen) % blockSize - } else if err != nil { - 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 < ivLen+authTagLen+1 { + errExit(fmt.Errorf("corrupt block: truncated data, len=%d", n)) + } + data := buf[:n] + // Parse block data + iv := data[:ivLen] + tag := data[len(data)-authTagLen:] + if aessiv { + tag = data[ivLen : ivLen+authTagLen] } fmt.Printf("Block %2d: IV: %s, Tag: %s, Offset: %5d Len: %d\n", - i, hex.EncodeToString(iv), hex.EncodeToString(tag), off, blockLen) + i, hex.EncodeToString(iv), hex.EncodeToString(tag), off, len(data)) } } diff --git a/gocryptfs-xray/xray_tests/aessiv_fs.masterkey.txt b/gocryptfs-xray/xray_tests/aessiv_fs.masterkey.txt new file mode 100644 index 0000000..70835ac --- /dev/null +++ b/gocryptfs-xray/xray_tests/aessiv_fs.masterkey.txt @@ -0,0 +1,5 @@ +Your master key is: + + 29dd219d-e227ff20-8474469d-9fc9fdc6- + b434ab35-404e808c-489d441e-2c1003f2 + diff --git a/gocryptfs-xray/xray_tests/aessiv_fs.xray.txt b/gocryptfs-xray/xray_tests/aessiv_fs.xray.txt new file mode 100644 index 0000000..6a48079 --- /dev/null +++ b/gocryptfs-xray/xray_tests/aessiv_fs.xray.txt @@ -0,0 +1,3 @@ +Header: Version: 2, Id: c2f21142e108952a47edfe16053d2bb9, assuming AES-SIV mode +Block 0: IV: 7621fdc35be7671ac6f369214436e8ff, Tag: e8108c158b22cad6bb3296645357eb75, Offset: 18 Len: 4128 +Block 1: IV: f096d86a4dc3461ef17655cfcf865b13, Tag: 925f23d647e4ab7add2c8d36362cc5a9, Offset: 4146 Len: 936 diff --git a/gocryptfs-xray/xray_tests/aessiv_fs/Ldq-c4ADpM5iGSSrPjUAqQ b/gocryptfs-xray/xray_tests/aessiv_fs/Ldq-c4ADpM5iGSSrPjUAqQ new file mode 100644 index 0000000..bfd4dfe Binary files /dev/null and b/gocryptfs-xray/xray_tests/aessiv_fs/Ldq-c4ADpM5iGSSrPjUAqQ differ diff --git a/gocryptfs-xray/xray_tests/aessiv_fs/gocryptfs.conf b/gocryptfs-xray/xray_tests/aessiv_fs/gocryptfs.conf new file mode 100644 index 0000000..9b8b95f --- /dev/null +++ b/gocryptfs-xray/xray_tests/aessiv_fs/gocryptfs.conf @@ -0,0 +1,21 @@ +{ + "Creator": "gocryptfs v1.7-beta1-7-g6b94f5e", + "EncryptedKey": "D0kHfg/pryMO9Ydo15EwpYjNHf3iWKq2GJyNocbjwJt9blEeMoLD5DnoARuDzQs54hblw+9MHwFjCSHYmJrFbA==", + "ScryptObject": { + "Salt": "ehn0LM/Hy/4QkXAMCZq3c3p0O9G7gu5e3OQSR8MiJ6c=", + "N": 65536, + "R": 8, + "P": 1, + "KeyLen": 32 + }, + "Version": 2, + "FeatureFlags": [ + "GCMIV128", + "HKDF", + "DirIV", + "EMENames", + "LongNames", + "Raw64", + "AESSIV" + ] +} diff --git a/gocryptfs-xray/xray_tests/aessiv_fs/gocryptfs.diriv b/gocryptfs-xray/xray_tests/aessiv_fs/gocryptfs.diriv new file mode 100644 index 0000000..dd57ce1 --- /dev/null +++ b/gocryptfs-xray/xray_tests/aessiv_fs/gocryptfs.diriv @@ -0,0 +1 @@ +.¨Í1Aiõ&Á4—öÉ \ No newline at end of file diff --git a/gocryptfs-xray/xray_tests/xray_test.go b/gocryptfs-xray/xray_tests/xray_test.go index a3374b0..8e5fc0c 100644 --- a/gocryptfs-xray/xray_tests/xray_test.go +++ b/gocryptfs-xray/xray_tests/xray_test.go @@ -24,3 +24,20 @@ func TestAesgcmXray(t *testing.T) { fmt.Printf("have:\n%s", string(out)) } } + +func TestAessivXray(t *testing.T) { + expected, err := ioutil.ReadFile("aessiv_fs.xray.txt") + if err != nil { + t.Fatal(err) + } + cmd := exec.Command("../gocryptfs-xray", "-aessiv", "aessiv_fs/Ldq-c4ADpM5iGSSrPjUAqQ") + out, err := cmd.CombinedOutput() + if err != nil { + t.Fatal(err) + } + if bytes.Compare(out, expected) != 0 { + t.Errorf("Unexpected output") + fmt.Printf("expected:\n%s", string(expected)) + fmt.Printf("have:\n%s", string(out)) + } +}
4 years ago
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",
xray: add support for inspecting AES-SIV files (-aessiv flag) https://github.com/rfjakob/gocryptfs/issues/299 : In GCM mode the auth tags are at the end of each block, but in SIV mode the auth tags follow immediately after the nonce. As a result, in AES-SIV mode the output of gocryptfs-xray is misleading and does not actually print the auth tag, but just the last 16-byte of the ciphertext. diff --git a/gocryptfs-xray/xray_main.go b/gocryptfs-xray/xray_main.go index 74c9fb3..5a81caf 100644 --- a/gocryptfs-xray/xray_main.go +++ b/gocryptfs-xray/xray_main.go @@ -16,9 +16,10 @@ import ( ) const ( - ivLen = contentenc.DefaultIVBits / 8 - blockSize = contentenc.DefaultBS + ivLen + cryptocore.AuthTagLen - myName = "gocryptfs-xray" + ivLen = contentenc.DefaultIVBits / 8 + authTagLen = cryptocore.AuthTagLen + blockSize = contentenc.DefaultBS + ivLen + cryptocore.AuthTagLen + myName = "gocryptfs-xray" ) func errExit(err error) { @@ -26,13 +27,18 @@ func errExit(err error) { os.Exit(1) } -func prettyPrintHeader(h *contentenc.FileHeader) { +func prettyPrintHeader(h *contentenc.FileHeader, aessiv bool) { id := hex.EncodeToString(h.ID) - fmt.Printf("Header: Version: %d, Id: %s\n", h.Version, id) + msg := "Header: Version: %d, Id: %s" + if aessiv { + msg += ", assuming AES-SIV mode" + } + fmt.Printf(msg+"\n", h.Version, id) } func main() { dumpmasterkey := flag.Bool("dumpmasterkey", false, "Decrypt and dump the master key") + aessiv := flag.Bool("aessiv", false, "Assume AES-SIV mode instead of AES-GCM") flag.Parse() if flag.NArg() != 1 { fmt.Fprintf(os.Stderr, "Usage: %s [OPTIONS] FILE\n"+ @@ -54,7 +60,7 @@ func main() { if *dumpmasterkey { dumpMasterKey(fn) } else { - inspectCiphertext(fd) + inspectCiphertext(fd, *aessiv) } } @@ -72,7 +78,7 @@ func dumpMasterKey(fn string) { } } -func inspectCiphertext(fd *os.File) { +func inspectCiphertext(fd *os.File, aessiv bool) { headerBytes := make([]byte, contentenc.HeaderLen) n, err := fd.ReadAt(headerBytes, 0) if err == io.EOF && n == 0 { @@ -88,34 +94,30 @@ func inspectCiphertext(fd *os.File) { if err != nil { errExit(err) } - prettyPrintHeader(header) + prettyPrintHeader(header, aessiv) var i int64 + buf := make([]byte, blockSize) for i = 0; ; i++ { - blockLen := int64(blockSize) off := contentenc.HeaderLen + i*blockSize - iv := make([]byte, ivLen) - _, err := fd.ReadAt(iv, off) - if err == io.EOF { - break - } else if err != nil { + n, err := fd.ReadAt(buf, off) + if err != nil && err != io.EOF { errExit(err) } - tag := make([]byte, cryptocore.AuthTagLen) - _, err = fd.ReadAt(tag, off+blockSize-cryptocore.AuthTagLen) - if err == io.EOF { - fi, err2 := fd.Stat() - if err2 != nil { - errExit(err2) - } - _, err2 = fd.ReadAt(tag, fi.Size()-cryptocore.AuthTagLen) - if err2 != nil { - errExit(err2) - } - blockLen = (fi.Size() - contentenc.HeaderLen) % blockSize - } else if err != nil { - 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 < ivLen+authTagLen+1 { + errExit(fmt.Errorf("corrupt block: truncated data, len=%d", n)) + } + data := buf[:n] + // Parse block data + iv := data[:ivLen] + tag := data[len(data)-authTagLen:] + if aessiv { + tag = data[ivLen : ivLen+authTagLen] } fmt.Printf("Block %2d: IV: %s, Tag: %s, Offset: %5d Len: %d\n", - i, hex.EncodeToString(iv), hex.EncodeToString(tag), off, blockLen) + i, hex.EncodeToString(iv), hex.EncodeToString(tag), off, len(data)) } } diff --git a/gocryptfs-xray/xray_tests/aessiv_fs.masterkey.txt b/gocryptfs-xray/xray_tests/aessiv_fs.masterkey.txt new file mode 100644 index 0000000..70835ac --- /dev/null +++ b/gocryptfs-xray/xray_tests/aessiv_fs.masterkey.txt @@ -0,0 +1,5 @@ +Your master key is: + + 29dd219d-e227ff20-8474469d-9fc9fdc6- + b434ab35-404e808c-489d441e-2c1003f2 + diff --git a/gocryptfs-xray/xray_tests/aessiv_fs.xray.txt b/gocryptfs-xray/xray_tests/aessiv_fs.xray.txt new file mode 100644 index 0000000..6a48079 --- /dev/null +++ b/gocryptfs-xray/xray_tests/aessiv_fs.xray.txt @@ -0,0 +1,3 @@ +Header: Version: 2, Id: c2f21142e108952a47edfe16053d2bb9, assuming AES-SIV mode +Block 0: IV: 7621fdc35be7671ac6f369214436e8ff, Tag: e8108c158b22cad6bb3296645357eb75, Offset: 18 Len: 4128 +Block 1: IV: f096d86a4dc3461ef17655cfcf865b13, Tag: 925f23d647e4ab7add2c8d36362cc5a9, Offset: 4146 Len: 936 diff --git a/gocryptfs-xray/xray_tests/aessiv_fs/Ldq-c4ADpM5iGSSrPjUAqQ b/gocryptfs-xray/xray_tests/aessiv_fs/Ldq-c4ADpM5iGSSrPjUAqQ new file mode 100644 index 0000000..bfd4dfe Binary files /dev/null and b/gocryptfs-xray/xray_tests/aessiv_fs/Ldq-c4ADpM5iGSSrPjUAqQ differ diff --git a/gocryptfs-xray/xray_tests/aessiv_fs/gocryptfs.conf b/gocryptfs-xray/xray_tests/aessiv_fs/gocryptfs.conf new file mode 100644 index 0000000..9b8b95f --- /dev/null +++ b/gocryptfs-xray/xray_tests/aessiv_fs/gocryptfs.conf @@ -0,0 +1,21 @@ +{ + "Creator": "gocryptfs v1.7-beta1-7-g6b94f5e", + "EncryptedKey": "D0kHfg/pryMO9Ydo15EwpYjNHf3iWKq2GJyNocbjwJt9blEeMoLD5DnoARuDzQs54hblw+9MHwFjCSHYmJrFbA==", + "ScryptObject": { + "Salt": "ehn0LM/Hy/4QkXAMCZq3c3p0O9G7gu5e3OQSR8MiJ6c=", + "N": 65536, + "R": 8, + "P": 1, + "KeyLen": 32 + }, + "Version": 2, + "FeatureFlags": [ + "GCMIV128", + "HKDF", + "DirIV", + "EMENames", + "LongNames", + "Raw64", + "AESSIV" + ] +} diff --git a/gocryptfs-xray/xray_tests/aessiv_fs/gocryptfs.diriv b/gocryptfs-xray/xray_tests/aessiv_fs/gocryptfs.diriv new file mode 100644 index 0000000..dd57ce1 --- /dev/null +++ b/gocryptfs-xray/xray_tests/aessiv_fs/gocryptfs.diriv @@ -0,0 +1 @@ +.¨Í1Aiõ&Á4—öÉ \ No newline at end of file diff --git a/gocryptfs-xray/xray_tests/xray_test.go b/gocryptfs-xray/xray_tests/xray_test.go index a3374b0..8e5fc0c 100644 --- a/gocryptfs-xray/xray_tests/xray_test.go +++ b/gocryptfs-xray/xray_tests/xray_test.go @@ -24,3 +24,20 @@ func TestAesgcmXray(t *testing.T) { fmt.Printf("have:\n%s", string(out)) } } + +func TestAessivXray(t *testing.T) { + expected, err := ioutil.ReadFile("aessiv_fs.xray.txt") + if err != nil { + t.Fatal(err) + } + cmd := exec.Command("../gocryptfs-xray", "-aessiv", "aessiv_fs/Ldq-c4ADpM5iGSSrPjUAqQ") + out, err := cmd.CombinedOutput() + if err != nil { + t.Fatal(err) + } + if bytes.Compare(out, expected) != 0 { + t.Errorf("Unexpected output") + fmt.Printf("expected:\n%s", string(expected)) + fmt.Printf("have:\n%s", string(out)) + } +}
4 years ago
i, hex.EncodeToString(iv), hex.EncodeToString(tag), off, len(data))
}
}