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Initial vault: single-binary post-quantum file vault

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Strip Fury back to its vault functionality in one `vault` command:
genkey, init, add (file or directory, optional folder inside the vault),
list, get, mv and rm.

The hybrid FrodoKEM-640 + ML-KEM-768 encryption core is kept under
internal/pqcrypt. Signing, policies, profiles, backups, SSH remotes,
FIDO2, agents, provenance and compression are removed.
This commit is contained in:
Andy Dixon
2026-09-26 14:05:10 +01:00
commit d95f2d04a4
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/vault
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# CLAUDE.md
This file provides guidance to Claude Code when working with this repository.
## Overview
vault is a post-quantum encrypted file vault: one `package main` at the repo
root that builds a single `vault` binary. Module `github.com/andydixon/vault`.
- `main.go` - CLI: `genkey`, `init`, `add`, `list`, `get`, `mv`, `rm`.
- `keyfile.go` - passphrase-protected key file (Argon2id +
XChaCha20-Poly1305 sealing a suite ID and 32-byte master seed).
- `store.go` - on-disk vault: `records/` holds fixed-size encrypted catalogue
records, `objects/` holds padded encrypted file bodies. Records a key cannot
open are skipped, not treated as errors.
- `internal/pqcrypt` - file encryption (header + STREAM ChaCha20-Poly1305),
suite registry, hybrid FrodoKEM-640 + ML-KEM-768 default suite.
- `internal/format`, `internal/stream`, `internal/term` - header encoding,
chunked payload encryption, terminal passphrase prompts.
## Commands
```sh
go test ./...
go build .
```
End-to-end check:
```sh
export VAULT_PASSPHRASE=test VAULT_KEY=$PWD/k VAULT_DIR=$PWD/s
./vault genkey && ./vault init && ./vault add README.md docs && ./vault list
```
## Invariants
- Never write a seed or private key unencrypted.
- Keep suite IDs, stanza tags, HKDF info strings and `fileKeySize` (32) stable.
- Every ciphertext's mtime is pinned to the epoch; records stay one fixed
size; objects stay bucket-padded. These hide metadata from the storage host.
- An object's plaintext starts with its own ID, binding it to its record.
- `get` publishes output only after the entire object has authenticated.
- Keep dependencies pure Go.
- Diagnostics go to standard error, lower-case, no trailing full stops.
LICENSE
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Program, unless a warranty or assumption of liability accompanies a
copy of the Program in return for a fee.
END OF TERMS AND CONDITIONS
How to Apply These Terms to Your New Programs
If you develop a new program, and you want it to be of the greatest
possible use to the public, the best way to achieve this is to make it
free software which everyone can redistribute and change under these terms.
To do so, attach the following notices to the program. It is safest
to attach them to the start of each source file to most effectively
state the exclusion of warranty; and each file should have at least
the "copyright" line and a pointer to where the full notice is found.
<one line to give the program's name and a brief idea of what it does.>
Copyright (C) <year> <name of author>
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>.
Also add information on how to contact you by electronic and paper mail.
If the program does terminal interaction, make it output a short
notice like this when it starts in an interactive mode:
<program> Copyright (C) <year> <name of author>
This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
This is free software, and you are welcome to redistribute it
under certain conditions; type `show c' for details.
The hypothetical commands `show w' and `show c' should show the appropriate
parts of the General Public License. Of course, your program's commands
might be different; for a GUI interface, you would use an "about box".
You should also get your employer (if you work as a programmer) or school,
if any, to sign a "copyright disclaimer" for the program, if necessary.
For more information on this, and how to apply and follow the GNU GPL, see
<https://www.gnu.org/licenses/>.
The GNU General Public License does not permit incorporating your program
into proprietary programs. If your program is a subroutine library, you
may consider it more useful to permit linking proprietary applications with
the library. If this is what you want to do, use the GNU Lesser General
Public License instead of this License. But first, please read
<https://www.gnu.org/licenses/why-not-lgpl.html>.
README.md
+51
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# vault
A post-quantum encrypted file vault in a single binary.
Files are encrypted with a hybrid FrodoKEM-640 + ML-KEM-768 key encapsulation
and ChaCha20-Poly1305. The vault directory holds only randomly named
ciphertexts. Names, sizes, modes and timestamps live inside encrypted
catalogue records of one fixed size. File bodies are padded to power-of-two
buckets.
## Build
```sh
go build . # produces ./vault
go test ./...
```
## Use
```sh
vault genkey # create ~/.vault/key, protected by a passphrase
vault init # create ~/.vault/store
vault add report.pdf # stored as report.pdf
vault add report.pdf work/2026 # stored as work/2026/report.pdf
vault add ./photos # every regular file under photos/
vault list # everything
vault list work # everything under work/
vault get work/2026/report.pdf # writes ./report.pdf
vault get report.pdf -o copy.pdf
vault mv report.pdf old/report.pdf
vault rm old/report.pdf
```
Adding a name that already exists replaces it. `get` refuses to overwrite an
existing file and writes nothing until the whole object has authenticated.
`--key PATH` and `--vault DIR` work with every command. They default to
`$VAULT_KEY` and `$VAULT_DIR`, then to `~/.vault/key` and `~/.vault/store`.
The passphrase is read from the terminal, or from `$VAULT_PASSPHRASE` for
scripts.
## Limits
- One writer at a time. Concurrent writes to the same vault are not locked.
- The storage host can see how many files exist, their size buckets and when
the vault changes.
- The key file is the only way in. Losing it or its passphrase loses the data.
## Licence
GPL-3.0-or-later. The cryptographic core is derived from Fury.
go.mod
+13
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@@ -0,0 +1,13 @@
module github.com/andydixon/vault
// Go 1.26.6 or newer is a security requirement inherited from the crypto
// library: the standard-library fixes it relies on exist only from that
// release.
go 1.26.6
require (
github.com/cloudflare/circl v1.6.4
golang.org/x/crypto v0.53.0
golang.org/x/sys v0.46.0
golang.org/x/term v0.44.0
)
go.sum
+8
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@@ -0,0 +1,8 @@
github.com/cloudflare/circl v1.6.4 h1:pOXuDTCEYyzydgUpQ0CQz3LsinKjiSk6nNP5Lt5K64U=
github.com/cloudflare/circl v1.6.4/go.mod h1:YxarevkLlbaHuWsxG6vmYNWBEsSp4pnp7j+4VljMavY=
golang.org/x/crypto v0.53.0 h1:QZ4Muo8THX6CizN2vPPd5fBGHyogrdK9fG4wLPFUsto=
golang.org/x/crypto v0.53.0/go.mod h1:DNLU434OwVakk9PzuwV8w62mAJpRJL3vsgcfp4Qnsio=
golang.org/x/sys v0.46.0 h1:noSf2Fq6F8DBgS+LysIkx7rIExoNHJsxOAtPp4rthXw=
golang.org/x/sys v0.46.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=
golang.org/x/term v0.44.0 h1:0rLvDRCtNj0gZkyIXhCyOb2OAzEhLVqc4B+hrsBhrmc=
golang.org/x/term v0.44.0/go.mod h1:7ze4MdzUzLXpSAoFP1H0bOI9aXDqveSvatT5vKcFh2Y=
internal/format/format.go
+356
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// SPDX-License-Identifier: GPL-3.0-or-later
// Package format implements the fury file format.
package format
import (
"bufio"
"bytes"
"encoding/base64"
"errors"
"fmt"
"io"
"strings"
)
const MaxHeaderSize = 16 << 20 // 16 MiB
const MaxStanzaSize = 1 << 20 // 1 MiB
type Header struct {
Recipients []*Stanza
MAC []byte
}
// Stanza is the serialised recipient block used in a fury header.
type Stanza struct {
Type string
Args []string
Body []byte
}
var b64 = base64.RawStdEncoding.Strict()
func DecodeString(s string) ([]byte, error) {
// CR and LF are ignored by DecodeString, but we don't want any malleability.
if strings.ContainsAny(s, "\n\r") {
return nil, errors.New(`unexpected newline character`)
}
return b64.DecodeString(s)
}
var EncodeToString = b64.EncodeToString
const ColumnsPerLine = 64
const BytesPerLine = ColumnsPerLine / 4 * 3
// NewWrappedBase64Encoder returns a WrappedBase64Encoder that writes to dst.
func NewWrappedBase64Encoder(enc *base64.Encoding, dst io.Writer) *WrappedBase64Encoder {
w := &WrappedBase64Encoder{dst: dst}
w.enc = base64.NewEncoder(enc, WriterFunc(w.writeWrapped))
return w
}
type WriterFunc func(p []byte) (int, error)
func (f WriterFunc) Write(p []byte) (int, error) { return f(p) }
// WrappedBase64Encoder is a standard base64 encoder that inserts an LF
// character every ColumnsPerLine bytes. It does not insert a newline neither at
// the beginning nor at the end of the stream, but it ensures the last line is
// shorter than ColumnsPerLine, which means it might be empty.
type WrappedBase64Encoder struct {
enc io.WriteCloser
dst io.Writer
written int
buf bytes.Buffer
}
func (w *WrappedBase64Encoder) Write(p []byte) (int, error) { return w.enc.Write(p) }
func (w *WrappedBase64Encoder) Close() error {
return w.enc.Close()
}
func (w *WrappedBase64Encoder) writeWrapped(p []byte) (int, error) {
if w.buf.Len() != 0 {
panic("fury: internal error: non-empty WrappedBase64Encoder.buf")
}
total := len(p)
for len(p) > 0 {
toWrite := min(ColumnsPerLine-(w.written%ColumnsPerLine), len(p))
n, _ := w.buf.Write(p[:toWrite])
w.written += n
p = p[n:]
if w.written%ColumnsPerLine == 0 {
w.buf.Write([]byte("\n"))
}
}
if _, err := w.buf.WriteTo(w.dst); err != nil {
// We always return n = 0 on error because it's hard to work back to the
// input length that ended up written out. Not ideal, but Write errors
// are not recoverable anyway.
return 0, err
}
return total, nil
}
// LastLineIsEmpty returns whether the last output line was empty, either
// because no input was written, or because a multiple of BytesPerLine was.
//
// Calling LastLineIsEmpty before Close is meaningless.
func (w *WrappedBase64Encoder) LastLineIsEmpty() bool {
return w.written%ColumnsPerLine == 0
}
const intro = "fury-encryption.org/v1\n"
var stanzaPrefix = []byte("->")
var footerPrefix = []byte("---")
func (r *Stanza) Marshal(w io.Writer) error {
if _, err := w.Write(stanzaPrefix); err != nil {
return err
}
for _, a := range append([]string{r.Type}, r.Args...) {
if _, err := io.WriteString(w, " "+a); err != nil {
return err
}
}
if _, err := io.WriteString(w, "\n"); err != nil {
return err
}
ww := NewWrappedBase64Encoder(b64, w)
if _, err := ww.Write(r.Body); err != nil {
return err
}
if err := ww.Close(); err != nil {
return err
}
_, err := io.WriteString(w, "\n")
return err
}
func (h *Header) MarshalWithoutMAC(w io.Writer) error {
if _, err := io.WriteString(w, intro); err != nil {
return err
}
for _, r := range h.Recipients {
if err := r.Marshal(w); err != nil {
return err
}
}
_, err := fmt.Fprintf(w, "%s", footerPrefix)
return err
}
func (h *Header) Marshal(w io.Writer) error {
if err := h.MarshalWithoutMAC(w); err != nil {
return err
}
mac := b64.EncodeToString(h.MAC)
_, err := fmt.Fprintf(w, " %s\n", mac)
return err
}
type StanzaReader struct {
r *bufio.Reader
err error
lastBytes int64
}
func NewStanzaReader(r *bufio.Reader) *StanzaReader {
return &StanzaReader{r: r}
}
func (r *StanzaReader) ReadStanza() (s *Stanza, err error) {
// Read errors are unrecoverable.
if r.err != nil {
return nil, r.err
}
var bytesRead int64
defer func() {
r.lastBytes = bytesRead
r.err = err
}()
s = &Stanza{}
line, err := readLimitedLine(r.r, &bytesRead, MaxStanzaSize)
if errors.Is(err, errSizeLimitExceeded) {
return nil, fmt.Errorf("stanza exceeds %d byte limit", MaxStanzaSize)
}
if err != nil {
return nil, fmt.Errorf("failed to read line: %w", err)
}
if !bytes.HasPrefix(line, stanzaPrefix) {
return nil, fmt.Errorf("malformed stanza opening line: %q", line)
}
prefix, args := splitArgs(line)
if prefix != string(stanzaPrefix) || len(args) < 1 {
return nil, fmt.Errorf("malformed stanza: %q", line)
}
for _, a := range args {
if !isValidString(a) {
return nil, fmt.Errorf("malformed stanza: %q", line)
}
}
s.Type = args[0]
s.Args = args[1:]
for {
line, err := readLimitedLine(r.r, &bytesRead, MaxStanzaSize)
if errors.Is(err, errSizeLimitExceeded) {
return nil, fmt.Errorf("stanza exceeds %d byte limit", MaxStanzaSize)
}
if err != nil {
return nil, fmt.Errorf("failed to read line: %w", err)
}
b, err := DecodeString(strings.TrimSuffix(string(line), "\n"))
if err != nil {
if bytes.HasPrefix(line, footerPrefix) || bytes.HasPrefix(line, stanzaPrefix) {
return nil, fmt.Errorf("malformed body line %q: stanza ended without a short line", line)
}
return nil, errorf("malformed body line %q: %v", line, err)
}
if len(b) > BytesPerLine {
return nil, errorf("malformed body line %q: too long", line)
}
s.Body = append(s.Body, b...)
if len(b) < BytesPerLine {
// A stanza body always ends with a short line.
return s, nil
}
}
}
var errSizeLimitExceeded = errors.New("size limit exceeded")
func readLimitedLine(r *bufio.Reader, bytesRead *int64, limit int64) ([]byte, error) {
var line []byte
for {
frag, err := r.ReadSlice('\n')
if len(frag) > 0 {
if limit > 0 && *bytesRead+int64(len(frag)) > limit {
return nil, errSizeLimitExceeded
}
*bytesRead += int64(len(frag))
line = append(line, frag...)
}
if err == nil {
return line, nil
}
if err != bufio.ErrBufferFull {
return nil, err
}
}
}
type ParseError struct {
err error
}
func (e *ParseError) Error() string {
return "parsing fury header: " + e.err.Error()
}
func (e *ParseError) Unwrap() error {
return e.err
}
func errorf(format string, a ...any) error {
return &ParseError{fmt.Errorf(format, a...)}
}
// Parse returns the header and a Reader that begins at the start of the
// payload.
func Parse(input io.Reader) (*Header, io.Reader, error) {
h := &Header{}
rr := bufio.NewReader(input)
var headerBytes int64
lineBytes, err := readLimitedLine(rr, &headerBytes, MaxHeaderSize)
line := string(lineBytes)
if errors.Is(err, errSizeLimitExceeded) {
return nil, nil, errorf("header exceeds %d byte limit", MaxHeaderSize)
}
if err == io.EOF {
return nil, nil, errorf("file is empty")
} else if err != nil {
return nil, nil, errorf("failed to read intro: %w", err)
}
if line != intro {
return nil, nil, errorf("unexpected intro: %q", line)
}
sr := NewStanzaReader(rr)
for {
peek, err := rr.Peek(len(footerPrefix))
if err != nil {
return nil, nil, errorf("failed to read header: %w", err)
}
if bytes.Equal(peek, footerPrefix) {
line, err := readLimitedLine(rr, &headerBytes, MaxHeaderSize)
if errors.Is(err, errSizeLimitExceeded) {
return nil, nil, errorf("header exceeds %d byte limit", MaxHeaderSize)
}
if err != nil {
return nil, nil, fmt.Errorf("failed to read header: %w", err)
}
prefix, args := splitArgs(line)
if prefix != string(footerPrefix) || len(args) != 1 {
return nil, nil, errorf("malformed closing line: %q", line)
}
h.MAC, err = DecodeString(args[0])
if err != nil || len(h.MAC) != 32 {
return nil, nil, errorf("malformed closing line %q: %v", line, err)
}
break
}
s, err := sr.ReadStanza()
if err != nil {
return nil, nil, fmt.Errorf("failed to parse header: %w", err)
}
headerBytes += sr.lastBytes
if headerBytes > MaxHeaderSize {
return nil, nil, errorf("header exceeds %d byte limit", MaxHeaderSize)
}
h.Recipients = append(h.Recipients, s)
}
// If input is a bufio.Reader, rr might be equal to input because
// bufio.NewReader short-circuits. In this case we can just return it (and
// we would end up reading the buffer twice if we prepended the peek below).
if rr == input {
return h, rr, nil
}
// Otherwise, unwind the bufio overread and return the unbuffered input.
buf, err := rr.Peek(rr.Buffered())
if err != nil {
return nil, nil, errorf("internal error: %v", err)
}
payload := io.MultiReader(bytes.NewReader(buf), input)
return h, payload, nil
}
func splitArgs(line []byte) (string, []string) {
l := strings.TrimSuffix(string(line), "\n")
parts := strings.Split(l, " ")
return parts[0], parts[1:]
}
func isValidString(s string) bool {
if len(s) == 0 {
return false
}
for _, c := range s {
if c < 33 || c > 126 {
return false
}
}
return true
}
internal/format/format_test.go
+90
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// SPDX-License-Identifier: GPL-3.0-or-later
package format_test
import (
"bufio"
"bytes"
"io"
"testing"
"github.com/andydixon/vault/internal/format"
)
func TestStanzaMarshal(t *testing.T) {
s := &format.Stanza{
Type: "test",
Args: []string{"1", "2", "3"},
Body: nil, // empty
}
buf := &bytes.Buffer{}
s.Marshal(buf)
if exp := "-> test 1 2 3\n\n"; buf.String() != exp {
t.Errorf("wrong empty stanza encoding: expected %q, got %q", exp, buf.String())
}
buf.Reset()
s.Body = []byte("AAA")
s.Marshal(buf)
if exp := "-> test 1 2 3\nQUFB\n"; buf.String() != exp {
t.Errorf("wrong normal stanza encoding: expected %q, got %q", exp, buf.String())
}
buf.Reset()
s.Body = bytes.Repeat([]byte("A"), format.BytesPerLine)
s.Marshal(buf)
if exp := "-> test 1 2 3\nQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFB\n\n"; buf.String() != exp {
t.Errorf("wrong 64 columns stanza encoding: expected %q, got %q", exp, buf.String())
}
}
func FuzzMalleability(f *testing.F) {
f.Fuzz(func(t *testing.T, data []byte) {
h, payload, err := format.Parse(bytes.NewReader(data))
if err != nil {
if h != nil {
t.Error("h != nil on error")
}
if payload != nil {
t.Error("payload != nil on error")
}
t.Skip()
}
w := &bytes.Buffer{}
if err := h.Marshal(w); err != nil {
t.Fatal(err)
}
if _, err := io.Copy(w, payload); err != nil {
t.Fatal(err)
}
if !bytes.Equal(w.Bytes(), data) {
t.Error("Marshal output different from input")
}
})
}
// FuzzStanza exercises the recipient-stanza reader directly. Parse reaches it
// only through a well-formed intro line, so fuzzing it on its own covers
// stanza shapes a whole-file seed cannot easily reach.
func FuzzStanza(f *testing.F) {
f.Fuzz(func(t *testing.T, data []byte) {
reader := format.NewStanzaReader(bufio.NewReader(bytes.NewReader(data)))
for range 64 {
stanza, err := reader.ReadStanza()
if err != nil {
if stanza != nil {
t.Fatal("stanza returned alongside an error")
}
return
}
if stanza == nil {
t.Fatal("no stanza and no error")
}
// Parser limits must hold: nothing an attacker supplies may make
// the reader materialise more than the stanza size limit.
if len(stanza.Body) > format.MaxStanzaSize {
t.Fatalf("stanza body of %d bytes exceeds the %d byte limit", len(stanza.Body), format.MaxStanzaSize)
}
}
})
}
internal/format/limits_test.go
+41
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// SPDX-License-Identifier: GPL-3.0-or-later
package format
import (
"bufio"
"bytes"
"strings"
"testing"
)
func TestStanzaReaderRejectsOversizedStanza(t *testing.T) {
var input bytes.Buffer
input.WriteString("-> test ")
input.WriteString(strings.Repeat("a", MaxStanzaSize))
input.WriteString("\n\n")
sr := NewStanzaReader(bufio.NewReader(&input))
if _, err := sr.ReadStanza(); err == nil {
t.Fatal("ReadStanza accepted an oversized stanza")
} else if !strings.Contains(err.Error(), "stanza exceeds") {
t.Fatalf("ReadStanza error = %v, want stanza size limit error", err)
}
}
func TestParseRejectsOversizedHeader(t *testing.T) {
var input bytes.Buffer
input.WriteString(intro)
for input.Len() <= MaxHeaderSize {
input.WriteString("-> test ")
input.WriteString(strings.Repeat("a", MaxStanzaSize-1024))
input.WriteString("\n\n")
}
input.WriteString("--- AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\n")
if _, _, err := Parse(&input); err == nil {
t.Fatal("Parse accepted an oversized header")
} else if !strings.Contains(err.Error(), "header exceeds") {
t.Fatalf("Parse error = %v, want header size limit error", err)
}
}
internal/pqcrypt/pqcrypt.go
+405
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// Copyright 2026 The fury Authors.
// SPDX-License-Identifier: GPL-3.0-or-later
//
// Package fury implements post-quantum file encryption. It provides a
// post-quantum-only file format, hybrid KEM key agreement, and a 256-bit file key.
//
// For most use cases, generate a [PQIdentity] with [GeneratePQIdentity], obtain
// its public [PQRecipient] with [PQIdentity.Recipient], and use the [Encrypt]
// and [Decrypt] functions.
//
// fury encrypted files are binary and not malleable. For encoding them as text,
// use the github.com/andydixon/fury/armor package.
//
// # Cryptographic agility
//
// Key agreement is provided by registered suites (see the suite registry).
// Each suite embeds its identifier in the file, so files remain decryptable as
// newer, stronger suites are added and made the default. The default suite is a
// hybrid of FrodoKEM-640 and ML-KEM-768: the file key stays secret unless both
// KEMs are broken.
//
// # Key management
//
// fury does not have a global keyring; generate dedicated keys per task. Public
// recipients are shared as "fury1..." strings (or, being large, as files), or
// referenced by a short "furyfp1..." fingerprint. Private identities are always
// encrypted, with passphrase recovery and optional external unlock slots; there
// is no API to serialise an unencrypted private key.
package pqcrypt
import (
"crypto/hmac"
"crypto/rand"
"errors"
"fmt"
"io"
"runtime"
"slices"
"sort"
"github.com/andydixon/vault/internal/format"
"github.com/andydixon/vault/internal/stream"
)
// An Identity is passed to [Decrypt] to unwrap an opaque file key from a
// recipient stanza. It can be for example a secret key like [HybridIdentity], a
// plugin, or a custom implementation.
type Identity interface {
// Unwrap must return an error wrapping [ErrIncorrectIdentity] if none of
// the recipient stanzas match the identity, any other error will be
// considered fatal.
//
// Most fury API users won't need to interact with this method directly, and
// should instead pass [Identity] implementations to [Decrypt].
Unwrap(stanzas []*Stanza) (fileKey []byte, err error)
}
// ErrIncorrectIdentity is returned by [Identity.Unwrap] if none of the
// recipient stanzas match the identity.
var ErrIncorrectIdentity = errors.New("incorrect identity for recipient block")
// A Recipient is passed to [Encrypt] to wrap an opaque file key to one or more
// recipient stanza(s). It can be for example a public key like [HybridRecipient],
// a plugin, or a custom implementation.
type Recipient interface {
// Most fury API users won't need to interact with this method directly, and
// should instead pass [Recipient] implementations to [Encrypt].
Wrap(fileKey []byte) ([]*Stanza, error)
}
// RecipientWithLabels can be optionally implemented by a [Recipient], in which
// case [Encrypt] will use WrapWithLabels instead of [Recipient.Wrap].
//
// Encrypt will succeed only if the labels returned by all the recipients
// (assuming the empty set for those that don't implement RecipientWithLabels)
// are the same.
//
// This can be used to ensure a recipient is only used with other recipients
// with equivalent properties (for example by setting a "postquantum" label) or
// to ensure a recipient is always used alone (by returning a random label, for
// example to preserve its authentication properties).
type RecipientWithLabels interface {
WrapWithLabels(fileKey []byte) (s []*Stanza, labels []string, err error)
}
// A Stanza is a section of the fury header that encapsulates the file key as
// encrypted to a specific recipient.
//
// Most fury API users won't need to interact with this type directly, and should
// instead pass [Recipient] implementations to [Encrypt] and [Identity]
// implementations to [Decrypt].
type Stanza struct {
Type string
Args []string
Body []byte
}
// fileKeySize is 32 bytes (256-bit) so the symmetric layer's post-quantum
// (Grover) security floor of ~128 bits matches the KEMs, rather than the 64-bit
// floor a 128-bit file key would impose. See suite.go and the payload STREAM.
const fileKeySize = 32
const streamNonceSize = 16
// maxAutoWorkers bounds the automatic worker count for parallel STREAM
// chunk encryption/decryption. ChaCha20-Poly1305 is memory-bandwidth-bound
// past a modest number of cores, so an unbounded runtime.NumCPU() on very
// large machines would just add goroutine/channel overhead for no benefit.
const maxAutoWorkers = 32
// MaxWorkers is the largest value [Options.Workers] will accept.
//
// The limit is set by what a worker actually costs, not by taste. Each worker
// may have two chunks in flight (see the stream package's pipeline depth), and
// a chunk is 64 KiB of plaintext plus its ciphertext buffer, so the pipeline
// holds roughly 256 KiB per worker: about 256 MiB at this limit, plus 1024
// goroutines and channels sized to match. That is already far past the point
// where throughput stops improving, and comfortably above the thread count of
// the largest machines currently shipping. A request beyond it is a
// configuration error rather than a tuning choice, so Fury rejects it instead
// of quietly attempting it or silently substituting another number.
const MaxWorkers = 1024
// Options configures [EncryptWithOptions] and [DecryptWithOptions] beyond
// the defaults used by [Encrypt] and [Decrypt].
type Options struct {
// Workers controls how many goroutines seal or open STREAM chunks in
// parallel. STREAM chunk nonces are a pure counter independent of chunk
// content, so parallelising this work never changes the resulting
// ciphertext or plaintext, only how fast it's produced.
//
// Valid values are 0 to [MaxWorkers]. Zero (the default) means
// automatic: runtime.NumCPU(), capped at a value past which
// ChaCha20-Poly1305 stops getting faster. One forces the sequential
// code path. A negative value, or one above MaxWorkers, is rejected.
Workers int
}
// ErrInvalidWorkers is returned when [Options.Workers] is outside 0 to
// [MaxWorkers].
var ErrInvalidWorkers = errors.New("fury: worker count out of range")
// Validate reports whether the options are usable. Every entry point that
// accepts [Options] calls it, so an out-of-range worker count is refused by
// the library itself and not only by the command-line tool.
func (o Options) Validate() error {
if o.Workers < 0 {
return fmt.Errorf("%w: %d is negative", ErrInvalidWorkers, o.Workers)
}
if o.Workers > MaxWorkers {
return fmt.Errorf("%w: %d exceeds the maximum of %d", ErrInvalidWorkers, o.Workers, MaxWorkers)
}
return nil
}
func (o Options) workers() int {
if o.Workers > 0 {
return o.Workers
}
if n := runtime.NumCPU(); n < maxAutoWorkers {
return n
}
return maxAutoWorkers
}
// encryptHdr wraps a file key to every recipient and authenticates the result.
//
// INVARIANT (no silent downgrade). All recipients must return identical label
// sets. A recipient that does not implement [RecipientWithLabels] contributes
// the empty set, so it can never be mixed with a "postquantum" recipient. Any
// future recipient type with weaker properties fails closed rather than
// quietly lowering the security of the whole file.
func encryptHdr(fileKey []byte, recipients ...Recipient) (*format.Header, error) {
if len(recipients) == 0 {
return nil, errors.New("no recipients specified")
}
hdr := &format.Header{}
var labels []string
for i, r := range recipients {
stanzas, l, err := wrapWithLabels(r, fileKey)
if err != nil {
return nil, fmt.Errorf("failed to wrap key for recipient #%d: %w", i, err)
}
sort.Strings(l)
if i == 0 {
labels = l
} else if !slices.Equal(labels, l) {
return nil, incompatibleLabelsError(labels, l)
}
for _, s := range stanzas {
hdr.Recipients = append(hdr.Recipients, (*format.Stanza)(s))
}
}
if mac, err := headerMAC(fileKey, hdr); err != nil {
return nil, fmt.Errorf("failed to compute header MAC: %v", err)
} else {
hdr.MAC = mac
}
return hdr, nil
}
// Encrypt encrypts a file to one or more recipients. Every recipient will be
// able to decrypt the file.
//
// Writes to the returned WriteCloser are encrypted and written to dst as a fury
// file. The caller must call Close on the WriteCloser when done for the last
// chunk to be encrypted and flushed to dst.
//
// The payload is sealed using multiple goroutines automatically; see
// [EncryptWithOptions] to control that.
func Encrypt(dst io.Writer, recipients ...Recipient) (io.WriteCloser, error) {
return EncryptWithOptions(dst, Options{}, recipients...)
}
// EncryptWithOptions is like [Encrypt], with explicit [Options].
//
// INVARIANT (fresh file key). Every call generates a new 32-byte file key
// from crypto/rand. Nothing derives a file key from the plaintext, the
// recipients or a counter, so no two encryptions share one.
func EncryptWithOptions(dst io.Writer, opts Options, recipients ...Recipient) (io.WriteCloser, error) {
if err := opts.Validate(); err != nil {
return nil, err
}
fileKey := make([]byte, fileKeySize)
if _, err := rand.Read(fileKey); err != nil {
return nil, fmt.Errorf("failed to generate file key: %w", err)
}
defer wipe(fileKey)
hdr, err := encryptHdr(fileKey, recipients...)
if err != nil {
return nil, err
}
if err := hdr.Marshal(dst); err != nil {
return nil, fmt.Errorf("failed to write header: %w", err)
}
nonce := make([]byte, streamNonceSize)
if _, err := rand.Read(nonce); err != nil {
return nil, fmt.Errorf("failed to generate nonce: %w", err)
}
if _, err := dst.Write(nonce); err != nil {
return nil, fmt.Errorf("failed to write nonce: %w", err)
}
key := streamKey(fileKey, nonce)
w, err := stream.NewParallelEncryptWriter(key, dst, opts.workers())
wipe(key)
return w, err
}
func wrapWithLabels(r Recipient, fileKey []byte) (s []*Stanza, labels []string, err error) {
if r, ok := r.(RecipientWithLabels); ok {
return r.WrapWithLabels(fileKey)
}
s, err = r.Wrap(fileKey)
return
}
func incompatibleLabelsError(l1, l2 []string) error {
hasPQ1 := slices.Contains(l1, "postquantum")
hasPQ2 := slices.Contains(l2, "postquantum")
if hasPQ1 != hasPQ2 {
return fmt.Errorf("incompatible recipients: can't mix post-quantum and classic recipients, or the file would be vulnerable to quantum computers")
}
return fmt.Errorf("incompatible recipients: %q and %q can't be mixed", l1, l2)
}
// NoIdentityMatchError is returned by [Decrypt] when none of the supplied
// identities match the encrypted file.
type NoIdentityMatchError struct {
// Errors is a slice of all the errors returned to Decrypt by the Unwrap
// calls it made. They all wrap [ErrIncorrectIdentity].
Errors []error
// StanzaTypes are the first argument of each recipient stanza in the
// encrypted file's header.
StanzaTypes []string
}
func (e *NoIdentityMatchError) Error() string {
if len(e.Errors) == 1 {
return "identity did not match any of the recipients: " + e.Errors[0].Error()
}
return "no identity matched any of the recipients"
}
// Decrypt decrypts a file encrypted to one or more identities.
// All identities will be tried until one successfully decrypts the file.
// Native, non-interactive identities are tried before any other identities.
//
// Decrypt returns a Reader reading the decrypted plaintext of the fury file read
// from src. If no identity matches the encrypted file, the returned error will
// be of type [NoIdentityMatchError].
//
// The payload is opened using multiple goroutines automatically; see
// [DecryptWithOptions] to control that.
func Decrypt(src io.Reader, identities ...Identity) (io.Reader, error) {
return DecryptWithOptions(src, Options{}, identities...)
}
// DecryptWithOptions is like [Decrypt], with explicit [Options].
func DecryptWithOptions(src io.Reader, opts Options, identities ...Identity) (io.Reader, error) {
if err := opts.Validate(); err != nil {
return nil, err
}
hdr, payload, err := format.Parse(src)
if err != nil {
return nil, fmt.Errorf("failed to read header: %w", err)
}
fileKey, err := decryptHdr(hdr, identities...)
if err != nil {
return nil, err
}
defer wipe(fileKey)
nonce := make([]byte, streamNonceSize)
if _, err := io.ReadFull(payload, nonce); err != nil {
return nil, fmt.Errorf("failed to read nonce: %w", err)
}
key := streamKey(fileKey, nonce)
r, err := stream.NewParallelDecryptReader(key, payload, opts.workers())
wipe(key)
return r, err
}
func decryptHdr(hdr *format.Header, identities ...Identity) ([]byte, error) {
if len(identities) == 0 {
return nil, errors.New("no identities specified")
}
slices.SortStableFunc(identities, func(a, b Identity) int {
var aIsNative, bIsNative bool
switch a.(type) {
case *PQIdentity:
aIsNative = true
}
switch b.(type) {
case *PQIdentity:
bIsNative = true
}
if aIsNative && !bIsNative {
return -1
}
if !aIsNative && bIsNative {
return 1
}
return 0
})
stanzas := make([]*Stanza, 0, len(hdr.Recipients))
errNoMatch := &NoIdentityMatchError{}
for _, s := range hdr.Recipients {
errNoMatch.StanzaTypes = append(errNoMatch.StanzaTypes, s.Type)
stanzas = append(stanzas, (*Stanza)(s))
}
var fileKey []byte
// The unwrapped key is copied out below; clear this copy on every exit
// path so it does not outlive the call. A closure is required: fileKey is
// assigned inside the loop, and a bare defer would capture today's nil.
defer func() { wipe(fileKey) }()
for _, id := range identities {
var err error
fileKey, err = id.Unwrap(stanzas)
if errors.Is(err, ErrIncorrectIdentity) {
errNoMatch.Errors = append(errNoMatch.Errors, err)
continue
}
if err != nil {
return nil, err
}
break
}
if fileKey == nil {
return nil, errNoMatch
}
if mac, err := headerMAC(fileKey, hdr); err != nil {
return nil, fmt.Errorf("failed to compute header MAC: %v", err)
} else if !hmac.Equal(mac, hdr.MAC) {
return nil, errors.New("bad header MAC")
}
return append([]byte(nil), fileKey...), nil
}
// multiUnwrap is a helper that implements Identity.Unwrap in terms of a
// function that unwraps a single recipient stanza.
func multiUnwrap(unwrap func(*Stanza) ([]byte, error), stanzas []*Stanza) ([]byte, error) {
for _, s := range stanzas {
fileKey, err := unwrap(s)
if errors.Is(err, ErrIncorrectIdentity) {
// If we ever start returning something interesting wrapping
// ErrIncorrectIdentity, we should let it make its way up through
// Decrypt into NoIdentityMatchError.Errors.
continue
}
if err != nil {
return nil, err
}
return fileKey, nil
}
return nil, ErrIncorrectIdentity
}
internal/pqcrypt/pqcrypt_test.go
+70
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@@ -0,0 +1,70 @@
// Copyright 2026 The fury Authors.
// SPDX-License-Identifier: GPL-3.0-or-later
package pqcrypt
import (
"bytes"
"crypto/rand"
"fmt"
"io"
"testing"
)
// TestEncryptWithOptionsRoundTrip exercises the parallel STREAM path end to
// end, at a size spanning many chunks, across a few explicit worker counts
// (including 1, which forces the original sequential code path).
func TestEncryptWithOptionsRoundTrip(t *testing.T) {
id, err := GeneratePQIdentity()
if err != nil {
t.Fatal(err)
}
r := id.Recipient()
plaintext := make([]byte, 4<<20) // 4 MiB: many STREAM chunks
if _, err := rand.Read(plaintext); err != nil {
t.Fatal(err)
}
for _, workers := range []int{1, 2, 8} {
t.Run(fmt.Sprintf("workers=%d", workers), func(t *testing.T) {
buf := &bytes.Buffer{}
w, err := EncryptWithOptions(buf, Options{Workers: workers}, r)
if err != nil {
t.Fatal(err)
}
if _, err := w.Write(plaintext); err != nil {
t.Fatal(err)
}
if err := w.Close(); err != nil {
t.Fatal(err)
}
out, err := DecryptWithOptions(bytes.NewReader(buf.Bytes()), Options{Workers: workers}, id)
if err != nil {
t.Fatal(err)
}
got, err := io.ReadAll(out)
if err != nil {
t.Fatal(err)
}
if !bytes.Equal(got, plaintext) {
t.Fatal("round-trip mismatch")
}
})
}
}
func TestOptionsWorkers(t *testing.T) {
if got := (Options{}).workers(); got <= 0 {
t.Fatalf("default workers = %d, want > 0", got)
}
if got := (Options{Workers: 3}).workers(); got != 3 {
t.Fatalf("explicit workers = %d, want 3", got)
}
// An explicit request is honoured even above the automatic cap; only the
// zero-value automatic path is capped.
if got := (Options{Workers: 1000}).workers(); got != 1000 {
t.Fatalf("explicit workers = %d, want 1000", got)
}
}
internal/pqcrypt/primitives.go
+111
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@@ -0,0 +1,111 @@
// SPDX-License-Identifier: GPL-3.0-or-later
package pqcrypt
import (
"crypto/hmac"
"crypto/sha256"
"errors"
"io"
"github.com/andydixon/vault/internal/format"
"golang.org/x/crypto/chacha20poly1305"
"golang.org/x/crypto/hkdf"
)
func wipe(b []byte) {
for i := range b {
b[i] = 0
}
}
// aeadEncrypt encrypts a message with a one-time key.
//
// INVARIANT (fixed nonce). The all-zero nonce below is safe only because
// every key reaching this function is a fresh, unique, single-use derived
// KEK. It is not a shortcut and must not be reused anywhere that condition
// does not hold: repeating a (key, nonce) pair under ChaCha20-Poly1305
// destroys both confidentiality and authenticity.
//
// The condition holds today because aeadEncrypt has exactly one caller, the
// default suite's wrap, whose KEK is
// HKDF-SHA-256(ss1 || ss2, info = label || ct1 || ct2). Both KEM
// encapsulations are performed freshly for each wrap, so ss1, ss2, ct1 and
// ct2 differ for every call even when the same file key is wrapped to the
// same recipient twice. Any new caller must establish the same property, or
// carry its own nonce.
//
// For the code that encrypts the actual payload, which uses a counter nonce
// rather than a fixed one, see the
// github.com/andydixon/vault/internal/stream package.
func aeadEncrypt(key, plaintext []byte) ([]byte, error) {
aead, err := chacha20poly1305.New(key)
if err != nil {
return nil, err
}
nonce := make([]byte, chacha20poly1305.NonceSize)
return aead.Seal(nil, nonce, plaintext, nil), nil
}
var errIncorrectCiphertextSize = errors.New("encrypted value has unexpected length")
// aeadDecrypt decrypts a message of an expected fixed size.
//
// The message size is limited to mitigate multi-key attacks, where a ciphertext
// can be crafted that decrypts successfully under multiple keys. Short
// ciphertexts can only target two keys, which has limited impact.
func aeadDecrypt(key []byte, size int, ciphertext []byte) ([]byte, error) {
aead, err := chacha20poly1305.New(key)
if err != nil {
return nil, err
}
if len(ciphertext) != size+aead.Overhead() {
return nil, errIncorrectCiphertextSize
}
nonce := make([]byte, chacha20poly1305.NonceSize)
return aead.Open(nil, nonce, ciphertext, nil)
}
// headerMAC computes the header authentication tag.
//
// INVARIANT (header authentication). The MAC covers the complete header
// except the MAC line itself: the intro line, every recipient stanza in
// order, and the footer prefix. Nothing that a decryptor acts upon is left
// unauthenticated, so a stanza cannot be added, removed, reordered or edited
// without detection by anyone who can recover the file key.
//
// INVARIANT (domain separation). The MAC key and the payload key are both
// HKDF-SHA-256 expansions of the same file key under distinct info strings
// ("header" and "payload"), so neither can be substituted for the other.
func headerMAC(fileKey []byte, hdr *format.Header) ([]byte, error) {
h := hkdf.New(sha256.New, fileKey, nil, []byte("header"))
hmacKey := make([]byte, 32)
if _, err := io.ReadFull(h, hmacKey); err != nil {
wipe(hmacKey)
return nil, err
}
// The MAC key is derived per call and is of no use once the hash is
// keyed, so it does not need to outlive this function.
defer wipe(hmacKey)
hh := hmac.New(sha256.New, hmacKey)
if err := hdr.MarshalWithoutMAC(hh); err != nil {
return nil, err
}
return hh.Sum(nil), nil
}
// streamKey derives the payload key.
//
// INVARIANT (payload key uniqueness). The 16-byte file nonce is fresh
// randomness written into every file and used here as the HKDF salt, so two
// encryptions never share a payload key even if a file key were somehow
// repeated. Combined with the STREAM counter nonce, no (key, nonce) pair is
// ever reused.
func streamKey(fileKey, nonce []byte) []byte {
h := hkdf.New(sha256.New, fileKey, nonce, []byte("payload"))
streamKey := make([]byte, chacha20poly1305.KeySize)
if _, err := io.ReadFull(h, streamKey); err != nil {
panic("fury: internal error: failed to read from HKDF: " + err.Error())
}
return streamKey
}
internal/pqcrypt/suite.go
+236
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@@ -0,0 +1,236 @@
// Copyright 2026 The fury Authors.
// SPDX-License-Identifier: GPL-3.0-or-later
package pqcrypt
import (
"crypto/rand"
"errors"
"fmt"
)
// A pqSuite is a registered post-quantum KEM suite. Each suite wraps the file
// key to a recipient and unwraps it with the corresponding identity. Suites are
// self-describing: their stanza tag is written into the header, so a file made
// with one suite keeps decrypting even after newer suites are added and made the
// default. This is the "use the best now, add better later, still decrypt older"
// property.
//
// Recipient public keys and identity private keys are opaque byte slices whose
// layout is defined by the suite. Identities are derived deterministically from
// a compact master seed so they can be stored and passphrase-wrapped cheaply.
type pqSuite interface {
// id is a stable numeric identifier embedded in recipient encodings.
id() uint16
// tag is the header stanza Type for this suite.
tag() string
// rank orders suites when picking a default; higher wins.
rank() int
// seedSize is the length of the master seed accepted by deriveKeypair.
seedSize() int
// deriveKeypair deterministically expands a master seed into a suite public
// key and private key.
deriveKeypair(seed []byte) (pub, priv []byte, err error)
// wrap encapsulates fileKey to pub, returning one or more header stanzas.
wrap(pub, fileKey []byte) ([]*Stanza, error)
// unwrap recovers fileKey from a stanza using priv. It must return an error
// wrapping ErrIncorrectIdentity if the stanza does not match.
unwrap(priv []byte, s *Stanza) ([]byte, error)
// publicKeySize is the expected length of a suite public key.
publicKeySize() int
}
var (
pqSuitesByTag = map[string]pqSuite{}
pqSuitesByID = map[uint16]pqSuite{}
)
// registerSuite adds a suite to the registry. It is called from suite files'
// init functions.
func registerSuite(s pqSuite) {
if _, ok := pqSuitesByTag[s.tag()]; ok {
panic("fury: duplicate suite tag " + s.tag())
}
if _, ok := pqSuitesByID[s.id()]; ok {
panic(fmt.Sprintf("fury: duplicate suite id %#04x", s.id()))
}
pqSuitesByTag[s.tag()] = s
pqSuitesByID[s.id()] = s
}
// defaultSuite returns the highest-ranked registered suite, used for key
// generation and encryption.
func defaultSuite() pqSuite {
var best pqSuite
for _, s := range pqSuitesByTag {
if best == nil || s.rank() > best.rank() {
best = s
}
}
if best == nil {
panic("fury: no PQ suites registered")
}
return best
}
// PQRecipient is a post-quantum public key. Messages encrypted to it can be
// decrypted with the corresponding [PQIdentity].
//
// It is anonymous: an observer can't tell from a message alone whether it is
// encrypted to a given recipient.
type PQRecipient struct {
suite pqSuite
pub []byte
}
var _ Recipient = &PQRecipient{}
var _ RecipientWithLabels = &PQRecipient{}
func (r *PQRecipient) Wrap(fileKey []byte) ([]*Stanza, error) {
return r.suite.wrap(r.pub, fileKey)
}
// WrapWithLabels returns a "postquantum" label so a PQRecipient can only be
// combined with other post-quantum recipients, never with a recipient type that
// would defeat its security.
func (r *PQRecipient) WrapWithLabels(fileKey []byte) ([]*Stanza, []string, error) {
s, err := r.Wrap(fileKey)
if err != nil {
return nil, nil, err
}
return s, []string{"postquantum"}, nil
}
// SuiteID returns the numeric identifier of the recipient's suite.
func (r *PQRecipient) SuiteID() uint16 { return r.suite.id() }
// Bytes returns the raw suite public key.
func (r *PQRecipient) Bytes() []byte { return append([]byte(nil), r.pub...) }
// PQIdentity is a post-quantum private key, derived from a compact master seed,
// which can decrypt messages encrypted to the corresponding [PQRecipient].
type PQIdentity struct {
suite pqSuite
seed []byte
pub []byte
priv []byte
}
var _ Identity = &PQIdentity{}
// GeneratePQIdentity randomly generates a new identity using the default suite.
func GeneratePQIdentity() (*PQIdentity, error) {
s := defaultSuite()
seed := make([]byte, s.seedSize())
if _, err := rand.Read(seed); err != nil {
return nil, fmt.Errorf("failed to generate seed: %w", err)
}
id, err := newPQIdentityFromSeed(s, seed)
wipe(seed)
return id, err
}
// newPQIdentityFromSeed derives an identity from a suite and master seed.
func newPQIdentityFromSeed(s pqSuite, seed []byte) (*PQIdentity, error) {
if len(seed) != s.seedSize() {
return nil, fmt.Errorf("invalid seed size %d for suite %s", len(seed), s.tag())
}
seed = append([]byte(nil), seed...)
pub, priv, err := s.deriveKeypair(seed)
if err != nil {
return nil, fmt.Errorf("failed to derive keypair: %w", err)
}
return &PQIdentity{suite: s, seed: seed, pub: pub, priv: priv}, nil
}
// usable reports whether the identity still holds its secret material. A
// closed identity, and one that was never fully initialised, both report
// false rather than panicking on a nil slice.
func (i *PQIdentity) usable() bool {
return i != nil && i.suite != nil && len(i.seed) == i.suite.seedSize() && len(i.priv) != 0
}
// ErrIdentityClosed is returned by operations on an identity whose secret
// material has been cleared by Close.
var ErrIdentityClosed = errors.New("fury identity is closed or uninitialised")
// Close overwrites the secret material this identity owns: its master seed
// and its expanded private key. Repeated calls are safe, and a partially
// initialised identity closes without panicking. The public key is retained,
// so [PQIdentity.Recipient] keeps working on a closed identity.
//
// Explicit overwriting shortens the lifetime of buffers Fury knows about. It
// cannot guarantee removal from physical memory: the Go compiler and runtime
// may have copied a value during allocation, garbage collection, stack growth
// or escape analysis, and Fury has no way to find or clear those copies. Treat
// this as defence in depth, not as erasure.
func (i *PQIdentity) Close() {
if i == nil {
return
}
wipe(i.seed)
wipe(i.priv)
i.seed, i.priv = nil, nil
}
func (i *PQIdentity) Unwrap(stanzas []*Stanza) ([]byte, error) {
if !i.usable() {
return nil, ErrIdentityClosed
}
return multiUnwrap(i.unwrap, stanzas)
}
func (i *PQIdentity) unwrap(s *Stanza) ([]byte, error) {
su, ok := pqSuitesByTag[s.Type]
if !ok || su.tag() != i.suite.tag() {
return nil, ErrIncorrectIdentity
}
fileKey, err := su.unwrap(i.priv, s)
if err != nil {
return nil, err
}
// Enforce the file key length centrally, so no future suite can feed a
// wrong-sized key into the payload STREAM by forgetting its own check.
if len(fileKey) != fileKeySize {
return nil, fmt.Errorf("suite %s returned a file key of %d bytes, want %d", su.tag(), len(fileKey), fileKeySize)
}
return fileKey, nil
}
// Recipient returns the public [PQRecipient] corresponding to i. It remains
// valid after [PQIdentity.Close], because a public key is not secret.
func (i *PQIdentity) Recipient() *PQRecipient {
return &PQRecipient{suite: i.suite, pub: append([]byte(nil), i.pub...)}
}
// Seed returns a copy of the compact master seed, or nil if the identity is
// closed.
//
// The returned slice is secret-equivalent: it regenerates both the private and
// the public key, so anything that can read it can decrypt everything the
// identity can. It must never be shared as a recipient, written unencrypted,
// logged, or passed to a subprocess.
//
// The copy is deliberate: it is never an alias into the identity's own buffer,
// so closing the identity does not clear it. From the moment it is returned it
// is the caller's responsibility to wipe it when finished and to keep its
// lifetime short.
func (i *PQIdentity) Seed() []byte {
if !i.usable() {
return nil
}
return append([]byte(nil), i.seed...)
}
// SuiteID returns the numeric identifier of the identity's suite.
func (i *PQIdentity) SuiteID() uint16 { return i.suite.id() }
// NewPQIdentityFromSeed derives an identity of the given suite from its master
// seed, as returned by [PQIdentity.Seed].
func NewPQIdentityFromSeed(suiteID uint16, seed []byte) (*PQIdentity, error) {
s, ok := pqSuitesByID[suiteID]
if !ok {
return nil, fmt.Errorf("unknown suite id %#04x", suiteID)
}
return newPQIdentityFromSeed(s, seed)
}
internal/pqcrypt/suite_frodo_mlkem.go
+215
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@@ -0,0 +1,215 @@
// Copyright 2026 The fury Authors.
// SPDX-License-Identifier: GPL-3.0-or-later
package pqcrypt
import (
"crypto/sha256"
"errors"
"fmt"
"io"
"slices"
"github.com/andydixon/vault/internal/format"
"github.com/cloudflare/circl/kem"
"github.com/cloudflare/circl/kem/frodo/frodo640shake"
"github.com/cloudflare/circl/kem/mlkem/mlkem768"
"golang.org/x/crypto/hkdf"
)
// frodoMLKEM768 is the default post-quantum suite: a hybrid of FrodoKEM-640
// (unstructured-lattice) and ML-KEM-768 (module-lattice). The file key stays
// secret unless both KEMs are broken. It is pure Go, so fury keeps building as a
// static binary with no cgo. (A code-based suite such as HQC or Classic McEliece
// via liboqs can be registered later with a higher rank; see suite.go.)
type frodoMLKEM768 struct{}
func init() { registerSuite(frodoMLKEM768{}) }
func (frodoMLKEM768) id() uint16 { return 0x0001 }
func (frodoMLKEM768) tag() string { return "frodo640shake+mlkem768" }
func (frodoMLKEM768) rank() int { return 10 }
func (frodoMLKEM768) seedSize() int { return 32 }
func (frodoMLKEM768) schemes() (frodo, ml kem.Scheme) {
return frodo640shake.Scheme(), mlkem768.Scheme()
}
func (s frodoMLKEM768) publicKeySize() int {
frodo, ml := s.schemes()
return frodo.PublicKeySize() + ml.PublicKeySize()
}
// deriveKeypair expands a 32-byte master seed into per-KEM seeds via HKDF, then
// derives each keypair deterministically. The public key is frodoPub||mlkemPub
// and the private key is frodoPriv||mlkemPriv.
func (s frodoMLKEM768) deriveKeypair(seed []byte) (pub, priv []byte, err error) {
frodo, ml := s.schemes()
r := hkdf.New(sha256.New, seed, nil, []byte("fury/v1 seed-expand "+s.tag()))
frodoSeed := make([]byte, frodo.SeedSize())
mlSeed := make([]byte, ml.SeedSize())
// The per-KEM seeds regenerate the private keys, so they are as sensitive
// as the master seed and are cleared as soon as the keys are derived.
defer wipe(frodoSeed)
defer wipe(mlSeed)
if _, err := io.ReadFull(r, frodoSeed); err != nil {
return nil, nil, err
}
if _, err := io.ReadFull(r, mlSeed); err != nil {
return nil, nil, err
}
fpk, fsk := frodo.DeriveKeyPair(frodoSeed)
mpk, msk := ml.DeriveKeyPair(mlSeed)
fpkb, err := fpk.MarshalBinary()
if err != nil {
return nil, nil, err
}
mpkb, err := mpk.MarshalBinary()
if err != nil {
return nil, nil, err
}
fskb, err := fsk.MarshalBinary()
if err != nil {
return nil, nil, err
}
defer wipe(fskb)
mskb, err := msk.MarshalBinary()
if err != nil {
return nil, nil, err
}
defer wipe(mskb)
// fpkb and mpkb are public key bytes; wiping them would be theatre.
return slices.Concat(fpkb, mpkb), slices.Concat(fskb, mskb), nil
}
// wrap encapsulates to both KEMs and seals the file key under the combined
// KEK.
//
// INVARIANT (fresh encapsulation). Both Encapsulate calls draw fresh
// randomness on every invocation. Wrapping the same file key to the same
// recipient twice therefore produces two independent KEKs, never a repeat.
func (s frodoMLKEM768) wrap(pub, fileKey []byte) ([]*Stanza, error) {
frodo, ml := s.schemes()
if len(pub) != s.publicKeySize() {
return nil, fmt.Errorf("invalid %s public key size", s.tag())
}
fpk, err := frodo.UnmarshalBinaryPublicKey(pub[:frodo.PublicKeySize()])
if err != nil {
return nil, fmt.Errorf("invalid FrodoKEM public key: %v", err)
}
mpk, err := ml.UnmarshalBinaryPublicKey(pub[frodo.PublicKeySize():])
if err != nil {
return nil, fmt.Errorf("invalid ML-KEM public key: %v", err)
}
ct1, ss1, err := frodo.Encapsulate(fpk)
if err != nil {
return nil, fmt.Errorf("FrodoKEM encapsulation failed: %v", err)
}
ct2, ss2, err := ml.Encapsulate(mpk)
if err != nil {
return nil, fmt.Errorf("ML-KEM encapsulation failed: %v", err)
}
kek := s.deriveKEK(ss1, ss2, ct1, ct2)
defer wipe(ss1)
defer wipe(ss2)
defer wipe(kek)
body, err := aeadEncrypt(kek, fileKey)
if err != nil {
return nil, fmt.Errorf("failed to wrap file key: %v", err)
}
return []*Stanza{{
Type: s.tag(),
Args: []string{format.EncodeToString(ct1), format.EncodeToString(ct2)},
Body: body,
}}, nil
}
func (s frodoMLKEM768) unwrap(priv []byte, st *Stanza) ([]byte, error) {
frodo, ml := s.schemes()
if st.Type != s.tag() {
return nil, ErrIncorrectIdentity
}
if len(st.Args) != 2 {
return nil, fmt.Errorf("invalid %s stanza: expected 2 arguments", s.tag())
}
ct1, err := format.DecodeString(st.Args[0])
if err != nil {
return nil, fmt.Errorf("invalid FrodoKEM ciphertext: %v", err)
}
ct2, err := format.DecodeString(st.Args[1])
if err != nil {
return nil, fmt.Errorf("invalid ML-KEM ciphertext: %v", err)
}
if len(ct1) != frodo.CiphertextSize() || len(ct2) != ml.CiphertextSize() {
return nil, errIncorrectCiphertextSize
}
if len(priv) != frodo.PrivateKeySize()+ml.PrivateKeySize() {
return nil, errors.New("invalid private key size")
}
fsk, err := frodo.UnmarshalBinaryPrivateKey(priv[:frodo.PrivateKeySize()])
if err != nil {
return nil, fmt.Errorf("invalid FrodoKEM private key: %v", err)
}
// priv itself belongs to the caller's identity and is cleared by
// PQIdentity.Close; the parsed key objects are owned by CIRCL and expose
// no buffer Fury can clear.
msk, err := ml.UnmarshalBinaryPrivateKey(priv[frodo.PrivateKeySize():])
if err != nil {
return nil, fmt.Errorf("invalid ML-KEM private key: %v", err)
}
ss1, err := frodo.Decapsulate(fsk, ct1)
if err != nil {
return nil, fmt.Errorf("FrodoKEM decapsulation failed: %v", err)
}
ss2, err := ml.Decapsulate(msk, ct2)
if err != nil {
return nil, fmt.Errorf("ML-KEM decapsulation failed: %v", err)
}
// Both KEMs use implicit rejection, so a mismatched key yields a wrong
// shared secret rather than an error; detection happens here at aeadDecrypt.
kek := s.deriveKEK(ss1, ss2, ct1, ct2)
defer wipe(ss1)
defer wipe(ss2)
defer wipe(kek)
fileKey, err := aeadDecrypt(kek, fileKeySize, st.Body)
if err != nil {
return nil, ErrIncorrectIdentity
}
return fileKey, nil
}
// deriveKEK combines the two KEM shared secrets and both ciphertexts into a
// 256-bit key-encryption key.
//
// INVARIANT (both secrets contribute). ss1 and ss2 are concatenated as the
// HKDF input keying material, so the KEK stays unpredictable unless both KEMs
// are broken for the same target. Dropping either would silently reduce the
// construction to a single KEM.
//
// INVARIANT (transcript binding). Both ciphertexts are bound into the HKDF
// info string, preventing a mix-and-match of encapsulations across the two
// KEMs: an attacker cannot pair ct1 from one stanza with ct2 from another and
// obtain a KEK either party would compute.
//
// INVARIANT (single use). Because both encapsulations are performed freshly
// for every wrap, the resulting KEK is unique to that wrap. That is what
// makes the fixed AEAD nonce in aeadEncrypt safe; see primitives.go.
func (s frodoMLKEM768) deriveKEK(ss1, ss2, ct1, ct2 []byte) []byte {
secret := slices.Concat(ss1, ss2)
defer wipe(secret)
info := slices.Concat([]byte("fury/v1 kek "+s.tag()), ct1, ct2)
r := hkdf.New(sha256.New, secret, nil, info)
kek := make([]byte, 32)
if _, err := io.ReadFull(r, kek); err != nil {
panic("fury: internal error: failed to read from HKDF: " + err.Error())
}
return kek
}
internal/pqcrypt/suite_test.go
+135
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// Copyright 2026 The fury Authors.
// SPDX-License-Identifier: GPL-3.0-or-later
package pqcrypt
import (
"bytes"
"io"
"testing"
)
// TestPQRoundTrip exercises the full Encrypt -> Decrypt path through the default
// post-quantum suite with a 256-bit file key.
func TestPQRoundTrip(t *testing.T) {
id, err := GeneratePQIdentity()
if err != nil {
t.Fatal(err)
}
r := id.Recipient()
plaintext := []byte("fury: post-quantum only, hard g like GIF")
buf := &bytes.Buffer{}
w, err := Encrypt(buf, r)
if err != nil {
t.Fatal(err)
}
if _, err := w.Write(plaintext); err != nil {
t.Fatal(err)
}
if err := w.Close(); err != nil {
t.Fatal(err)
}
out, err := Decrypt(bytes.NewReader(buf.Bytes()), id)
if err != nil {
t.Fatal(err)
}
got, err := io.ReadAll(out)
if err != nil {
t.Fatal(err)
}
if !bytes.Equal(got, plaintext) {
t.Fatalf("round-trip mismatch: got %q want %q", got, plaintext)
}
}
func TestPQFileKeyIs256Bit(t *testing.T) {
if fileKeySize != 32 {
t.Fatalf("fileKeySize = %d, want 32 (256-bit)", fileKeySize)
}
}
// TestPQWrongIdentity confirms a different identity cannot decrypt.
func TestPQWrongIdentity(t *testing.T) {
id, _ := GeneratePQIdentity()
other, _ := GeneratePQIdentity()
buf := &bytes.Buffer{}
w, err := Encrypt(buf, id.Recipient())
if err != nil {
t.Fatal(err)
}
w.Write([]byte("secret"))
w.Close()
if _, err := Decrypt(bytes.NewReader(buf.Bytes()), other); err == nil {
t.Fatal("decryption with wrong identity unexpectedly succeeded")
}
}
// TestSuiteRegistry checks the default suite is registered and self-describing.
func TestSuiteRegistry(t *testing.T) {
s := defaultSuite()
if s.tag() != "frodo640shake+mlkem768" {
t.Fatalf("unexpected default suite %q", s.tag())
}
if pqSuitesByID[s.id()] != s {
t.Fatal("suite not registered by id")
}
if pqSuitesByTag[s.tag()] != s {
t.Fatal("suite not registered by tag")
}
}
// TestSeedDeterministic confirms an identity round-trips through its seed, which
// is what makes compact passphrase-wrapped identities possible.
func TestSeedDeterministic(t *testing.T) {
id, err := GeneratePQIdentity()
if err != nil {
t.Fatal(err)
}
id2, err := newPQIdentityFromSeed(defaultSuite(), id.Seed())
if err != nil {
t.Fatal(err)
}
if !bytes.Equal(id.pub, id2.pub) || !bytes.Equal(id.priv, id2.priv) {
t.Fatal("identity not deterministic from seed")
}
}
func TestIdentityAndRecipientAccessorsReturnCopies(t *testing.T) {
id, err := GeneratePQIdentity()
if err != nil {
t.Fatal(err)
}
seed := id.Seed()
seed[0] ^= 0xff
if id.seed[0] == seed[0] {
t.Fatal("Seed returned mutable identity internals")
}
inputSeed := id.Seed()
id2, err := newPQIdentityFromSeed(defaultSuite(), inputSeed)
if err != nil {
t.Fatal(err)
}
inputSeed[0] ^= 0xff
if id2.seed[0] == inputSeed[0] {
t.Fatal("newPQIdentityFromSeed retained caller-owned seed slice")
}
recipient := id.Recipient()
pub := recipient.Bytes()
pub[0] ^= 0xff
if recipient.pub[0] == pub[0] {
t.Fatal("Bytes returned mutable recipient internals")
}
recipient.pub[0] ^= 0xff
if id.pub[0] == recipient.pub[0] {
t.Fatal("Recipient returned mutable identity public-key internals")
}
}
internal/stream/parallel_decrypt.go
+271
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@@ -0,0 +1,271 @@
// Copyright 2026 The fury Authors.
// SPDX-License-Identifier: GPL-3.0-or-later
package stream
import (
"crypto/cipher"
"errors"
"fmt"
"io"
"sync"
"golang.org/x/crypto/chacha20poly1305"
)
// NewParallelDecryptReader is equivalent to [NewDecryptReader], except that
// chunks are opened by a pool of worker goroutines instead of inline on the
// calling goroutine.
//
// The sequential DecryptReader disambiguates a full-length final chunk by
// trying to open it with the non-last nonce first and, on authentication
// failure, retrying with the last-chunk nonce. That trick is inherently
// sequential (try, then fall back), so this reader instead keeps a single
// raw chunk of read-ahead: the one goroutine that reads from src (reads must
// stay sequential, there is only one underlying stream) always reads one
// chunk further than it has dispatched, so by the time chunk i is handed to
// the worker pool, whether it is the last chunk is already known for
// certain from the shape of the next read. Each worker then does exactly
// one Open call, with a predetermined nonce, no retry.
//
// For well-formed files this produces byte-for-byte identical plaintext and
// the same errors as NewDecryptReader. For adversarially malformed files,
// the accept/reject verdict is always the same, but the exact error message
// in some corner cases (a corrupted chunk that happens to be full-length)
// may differ, because the classification strategy differs; see the package
// tests for the cases this was checked against.
//
// workers <= 1 returns a plain [NewDecryptReader] with no pipeline overhead.
//
// The returned Reader starts background goroutines that run until the
// stream is fully consumed or a fatal error occurs; abandoning it before
// reading to EOF leaks those goroutines (bounded to a small multiple of
// workers) until they unblock or the process exits.
func NewParallelDecryptReader(key []byte, src io.Reader, workers int) (io.Reader, error) {
if workers <= 1 {
return NewDecryptReader(key, src)
}
aead, err := chacha20poly1305.New(key)
if err != nil {
return nil, err
}
depth := workers * pipelineDepthPerWorker
r := &parallelDecryptReader{
a: aead,
src: src,
jobs: make(chan decJob, depth),
order: make(chan chan decResult, depth),
}
r.wg.Add(workers)
for i := 0; i < workers; i++ {
go r.work()
}
go r.pump()
return r, nil
}
type decJob struct {
nonce [chacha20poly1305.NonceSize]byte
ciphertext []byte
result chan decResult
}
// decResult is either a successfully decrypted chunk (err == nil) or a
// terminal event: a decryption failure, a raw read error, or a trailing-data
// violation. There is no explicit "clean EOF" value: a clean end of stream
// is represented by the order channel closing with nothing left to receive.
type decResult struct {
plaintext []byte
err error
}
type parallelDecryptReader struct {
a cipher.AEAD
src io.Reader
jobs chan decJob
order chan chan decResult
wg sync.WaitGroup
unread []byte
err error
}
func (r *parallelDecryptReader) Read(p []byte) (int, error) {
if len(r.unread) > 0 {
n := copy(p, r.unread)
r.unread = r.unread[n:]
return n, nil
}
if r.err != nil {
return 0, r.err
}
if len(p) == 0 {
return 0, nil
}
ch, ok := <-r.order
if !ok {
r.err = io.EOF
return 0, r.err
}
res := <-ch
if res.err != nil {
r.err = res.err
return 0, r.err
}
r.unread = res.plaintext
n := copy(p, r.unread)
r.unread = r.unread[n:]
return n, nil
}
// dispatch hands a raw chunk, whose classification is already known for
// certain, to the worker pool.
func (r *parallelDecryptReader) dispatch(index int64, ciphertext []byte, last bool) {
nonce := nonceForChunk(index)
if last {
setLastChunkFlag(nonce)
}
ch := make(chan decResult, 1)
r.order <- ch
r.jobs <- decJob{nonce: *nonce, ciphertext: ciphertext, result: ch}
}
// emitDirect enqueues a terminal result produced by the pump goroutine
// itself (a read error, a malformed-stream error, or a trailing-data
// violation), without involving the worker pool.
func (r *parallelDecryptReader) emitDirect(res decResult) {
ch := make(chan decResult, 1)
r.order <- ch
ch <- res
}
// work opens dispatched chunks. Unlike the sequential reader, there is no
// retry here: the pump goroutine has already determined, from the shape of
// the raw stream, whether each chunk is the last one.
func (r *parallelDecryptReader) work() {
defer r.wg.Done()
for j := range r.jobs {
out := make([]byte, 0, ChunkSize)
plaintext, err := r.a.Open(out, j.nonce[:], j.ciphertext, nil)
if err != nil {
j.result <- decResult{err: errors.New("failed to decrypt and authenticate payload chunk, file may be corrupted or tampered with")}
continue
}
j.result <- decResult{plaintext: plaintext}
}
}
type chunkKind int
const (
chunkFull chunkKind = iota
chunkShort
chunkEOF
chunkErr
)
type rawChunk struct {
kind chunkKind
data []byte
err error
}
// readRawChunk reads exactly one raw encChunkSize block from src into a
// freshly allocated buffer and classifies the read, mirroring the switch at
// the top of the sequential DecryptReader.readChunk.
func readRawChunk(src io.Reader) rawChunk {
buf := make([]byte, encChunkSize)
n, err := io.ReadFull(src, buf)
switch {
case err == nil:
return rawChunk{kind: chunkFull, data: buf}
case err == io.EOF:
return rawChunk{kind: chunkEOF}
case err == io.ErrUnexpectedEOF:
return rawChunk{kind: chunkShort, data: buf[:n]}
default:
return rawChunk{kind: chunkErr, err: err}
}
}
// pump is the single goroutine that reads raw chunks from src, in order,
// always staying one chunk ahead so that every dispatched chunk's
// last-chunk status is already certain. It closes r.jobs and r.order when
// the stream ends or a fatal error is found, which is what lets Read
// observe a clean end of stream (order closed with nothing left) versus an
// explicit terminal error (an emitDirect result).
func (r *parallelDecryptReader) pump() {
defer close(r.jobs)
defer close(r.order)
first := readRawChunk(r.src)
switch first.kind {
case chunkErr:
r.emitDirect(decResult{err: first.err})
return
case chunkEOF:
// A message can't end without a marked chunk; this message is
// truncated, exactly like the sequential reader's first read.
r.emitDirect(decResult{err: io.ErrUnexpectedEOF})
return
case chunkShort:
// This is chunk index 0: an empty chunk here is the valid
// empty-plaintext-file case, not the "empty last chunk" error,
// which can only apply to a later chunk.
r.dispatch(0, first.data, true)
r.probeTrailing()
return
}
// first.kind == chunkFull: ambiguous until we see what follows it.
pendingIndex := int64(0)
pending := first.data
for {
next := readRawChunk(r.src)
switch next.kind {
case chunkErr:
r.dispatch(pendingIndex, pending, false)
r.emitDirect(decResult{err: next.err})
return
case chunkEOF:
// Nothing follows: pending was a full-length final chunk. The
// clean EOF we just observed is itself the trailing-data proof,
// no separate probe needed.
r.dispatch(pendingIndex, pending, true)
return
case chunkShort:
r.dispatch(pendingIndex, pending, false)
if len(next.data) == chacha20poly1305.Overhead {
// A short chunk here is never index 0, so an empty one is
// always the disallowed case.
r.emitDirect(decResult{err: errors.New("last chunk is empty; encrypted payload is malformed")})
return
}
r.dispatch(pendingIndex+1, next.data, true)
r.probeTrailing()
return
case chunkFull:
r.dispatch(pendingIndex, pending, false)
pendingIndex++
pending = next.data
continue
}
}
}
// probeTrailing confirms there is no data after a short final chunk, exactly
// as the sequential DecryptReader.Read does after processing a last chunk.
func (r *parallelDecryptReader) probeTrailing() {
var b [1]byte
_, err := r.src.Read(b[:])
switch {
case err == nil:
r.emitDirect(decResult{err: errors.New("trailing data after end of encrypted file")})
case err != io.EOF:
r.emitDirect(decResult{err: fmt.Errorf("non-EOF error reading after end of encrypted file: %w", err)})
}
}
internal/stream/parallel_encrypt.go
+192
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@@ -0,0 +1,192 @@
// Copyright 2026 The fury Authors.
// SPDX-License-Identifier: GPL-3.0-or-later
package stream
import (
"bytes"
"crypto/cipher"
"errors"
"io"
"sync"
"golang.org/x/crypto/chacha20poly1305"
)
// pipelineDepthPerWorker bounds how many chunks may be queued for, or
// awaiting collection from, a single worker at once. It caps the pipeline's
// memory use to a small multiple of ChunkSize regardless of input size.
const pipelineDepthPerWorker = 2
// NewParallelEncryptWriter is equivalent to [NewEncryptWriter], except that
// chunks are sealed by a pool of worker goroutines instead of inline on the
// calling goroutine. Its output is byte-for-byte identical to
// NewEncryptWriter's: STREAM chunk nonces are a pure counter, so sealing
// chunk i never depends on chunk i-1. Only the write order to dst must stay
// sequential, which a dedicated collector goroutine enforces.
//
// workers <= 1 returns a plain [NewEncryptWriter] with no pipeline overhead.
func NewParallelEncryptWriter(key []byte, dst io.Writer, workers int) (io.WriteCloser, error) {
if workers <= 1 {
return NewEncryptWriter(key, dst)
}
aead, err := chacha20poly1305.New(key)
if err != nil {
return nil, err
}
depth := workers * pipelineDepthPerWorker
w := &parallelEncryptWriter{
a: aead,
dst: dst,
jobs: make(chan encJob, depth),
order: make(chan chan []byte, depth),
done: make(chan struct{}),
}
w.wg.Add(workers)
for i := 0; i < workers; i++ {
go w.work()
}
go w.collect()
return w, nil
}
type encJob struct {
nonce [chacha20poly1305.NonceSize]byte
plaintext []byte
result chan []byte
}
type parallelEncryptWriter struct {
a cipher.AEAD
dst io.Writer
buf bytes.Buffer
index int64
jobs chan encJob
order chan chan []byte
wg sync.WaitGroup
done chan struct{} // closed once the collector goroutine has returned
mu sync.Mutex
err error
}
func (w *parallelEncryptWriter) getErr() error {
w.mu.Lock()
defer w.mu.Unlock()
return w.err
}
func (w *parallelEncryptWriter) setErr(err error) {
w.mu.Lock()
defer w.mu.Unlock()
if w.err == nil {
w.err = err
}
}
func (w *parallelEncryptWriter) Write(p []byte) (n int, err error) {
if err := w.getErr(); err != nil {
return 0, err
}
if len(p) == 0 {
return 0, nil
}
total := len(p)
for len(p) > 0 {
room := ChunkSize - w.buf.Len()
nn := min(len(p), room)
w.buf.Write(p[:nn])
p = p[nn:]
// Only submit a chunk once we know more data is coming, so the very
// last chunk (submitted from Close) is always the one that gets the
// last-chunk-flag nonce, exactly like the sequential EncryptWriter.
if w.buf.Len() == ChunkSize && len(p) > 0 {
if err := w.submitChunk(false); err != nil {
w.setErr(err)
return 0, err
}
}
}
return total, nil
}
// Close flushes the last chunk and waits for every queued chunk to be
// sealed and written to dst, in order. It does not close the underlying
// Writer.
func (w *parallelEncryptWriter) Close() error {
if err := w.getErr(); err != nil {
return err
}
// submitChunk cannot fail here: we just confirmed there is no prior
// error, and channel sends to w.jobs/w.order only block, they never
// return an error.
_ = w.submitChunk(true)
close(w.jobs)
close(w.order)
w.wg.Wait()
<-w.done
if err := w.getErr(); err != nil {
return err
}
w.setErr(errors.New("stream.Writer is already closed"))
return nil
}
// submitChunk copies out the current buffer as a chunk of plaintext, assigns
// it the next sequential nonce, and hands it to the worker pool. last must be
// true only for the final call, made from Close.
func (w *parallelEncryptWriter) submitChunk(last bool) error {
if err := w.getErr(); err != nil {
return err
}
plaintext := append([]byte(nil), w.buf.Bytes()...)
w.buf.Reset()
nonce := nonceForChunk(w.index)
if last {
setLastChunkFlag(nonce)
}
w.index++
result := make(chan []byte, 1)
w.order <- result
w.jobs <- encJob{nonce: *nonce, plaintext: plaintext, result: result}
return nil
}
// work seals queued chunks. Seal cannot fail: the nonce is always the
// correct size, so the only possible failure in this pipeline is dst.Write,
// handled in collect.
func (w *parallelEncryptWriter) work() {
defer w.wg.Done()
for j := range w.jobs {
ciphertext := w.a.Seal(make([]byte, 0, len(j.plaintext)+w.a.Overhead()), j.nonce[:], j.plaintext, nil)
j.result <- ciphertext
}
}
// collect writes sealed chunks to dst strictly in submission order, even
// though workers may finish sealing them in a different order.
func (w *parallelEncryptWriter) collect() {
defer close(w.done)
var failed bool
for result := range w.order {
ciphertext := <-result
if failed {
continue
}
if _, err := w.dst.Write(ciphertext); err != nil {
w.setErr(err)
failed = true
}
}
}
internal/stream/parallel_test.go
+332
View File
@@ -0,0 +1,332 @@
// Copyright 2026 The fury Authors.
// SPDX-License-Identifier: GPL-3.0-or-later
package stream_test
import (
"bytes"
"crypto/cipher"
"crypto/rand"
"encoding/binary"
"fmt"
"io"
"runtime"
"testing"
"github.com/andydixon/vault/internal/stream"
"golang.org/x/crypto/chacha20poly1305"
)
func workerCounts() []int {
return []int{1, 2, 4, runtime.NumCPU() + 4}
}
func randBytes(t *testing.T, n int) []byte {
t.Helper()
b := make([]byte, n)
if _, err := rand.Read(b); err != nil {
t.Fatal(err)
}
return b
}
// TestParallelEncryptMatchesSequential is the main compatibility check: for a
// range of lengths and worker counts, the parallel encrypter must produce
// byte-identical ciphertext to the sequential one, and ciphertext from
// either encrypter must decrypt correctly with either reader.
func TestParallelEncryptMatchesSequential(t *testing.T) {
lengths := []int{0, 1000, cs - 1, cs, cs + 1, cs + 100, 2 * cs, 2*cs + 500}
for _, length := range lengths {
for _, workers := range workerCounts() {
t.Run(fmt.Sprintf("len=%d,workers=%d", length, workers), func(t *testing.T) {
src := randBytes(t, length)
key := randBytes(t, chacha20poly1305.KeySize)
seqBuf := &bytes.Buffer{}
sw, err := stream.NewEncryptWriter(key, seqBuf)
if err != nil {
t.Fatal(err)
}
if _, err := sw.Write(src); err != nil {
t.Fatal(err)
}
if err := sw.Close(); err != nil {
t.Fatal(err)
}
parBuf := &bytes.Buffer{}
pw, err := stream.NewParallelEncryptWriter(key, parBuf, workers)
if err != nil {
t.Fatal(err)
}
if _, err := pw.Write(src); err != nil {
t.Fatal(err)
}
if err := pw.Close(); err != nil {
t.Fatal(err)
}
if !bytes.Equal(seqBuf.Bytes(), parBuf.Bytes()) {
t.Fatalf("parallel ciphertext (%d bytes) differs from sequential (%d bytes)",
parBuf.Len(), seqBuf.Len())
}
t.Run("decrypt-with-sequential", func(t *testing.T) {
dr, err := stream.NewDecryptReader(key, bytes.NewReader(parBuf.Bytes()))
if err != nil {
t.Fatal(err)
}
checkRoundTrip(t, dr, src)
})
t.Run("decrypt-with-parallel", func(t *testing.T) {
dr, err := stream.NewParallelDecryptReader(key, bytes.NewReader(parBuf.Bytes()), workers)
if err != nil {
t.Fatal(err)
}
checkRoundTrip(t, dr, src)
})
t.Run("sequential-ciphertext-decrypts-with-parallel", func(t *testing.T) {
dr, err := stream.NewParallelDecryptReader(key, bytes.NewReader(seqBuf.Bytes()), workers)
if err != nil {
t.Fatal(err)
}
checkRoundTrip(t, dr, src)
})
})
}
}
}
func checkRoundTrip(t *testing.T, r io.Reader, want []byte) {
t.Helper()
got, err := io.ReadAll(r)
if err != nil {
t.Fatalf("unexpected error: %v", err)
}
if !bytes.Equal(got, want) {
t.Fatalf("decrypted mismatch: got %d bytes, want %d bytes", len(got), len(want))
}
}
// TestParallelEncryptWriteInSteps confirms the parallel writer's output is
// unaffected by how the caller chunks its Write calls, mirroring the
// sequential TestRoundTrip's step-size coverage but scoped to a couple of
// representative lengths to keep runtime reasonable.
func TestParallelEncryptWriteInSteps(t *testing.T) {
lengths := []int{cs + 100, 2*cs + 500}
steps := []int{1, 537, cs}
for _, length := range lengths {
for _, step := range steps {
t.Run(fmt.Sprintf("len=%d,step=%d", length, step), func(t *testing.T) {
src := randBytes(t, length)
key := randBytes(t, chacha20poly1305.KeySize)
seqBuf := &bytes.Buffer{}
sw, err := stream.NewEncryptWriter(key, seqBuf)
if err != nil {
t.Fatal(err)
}
writeInSteps(t, sw, src, step)
if err := sw.Close(); err != nil {
t.Fatal(err)
}
parBuf := &bytes.Buffer{}
pw, err := stream.NewParallelEncryptWriter(key, parBuf, 4)
if err != nil {
t.Fatal(err)
}
writeInSteps(t, pw, src, step)
if err := pw.Close(); err != nil {
t.Fatal(err)
}
if !bytes.Equal(seqBuf.Bytes(), parBuf.Bytes()) {
t.Fatalf("parallel ciphertext differs from sequential with step=%d", step)
}
})
}
}
}
func writeInSteps(t *testing.T, w io.Writer, src []byte, step int) {
t.Helper()
for len(src) > 0 {
n := min(step, len(src))
if _, err := w.Write(src[:n]); err != nil {
t.Fatal(err)
}
src = src[n:]
}
}
// TestParallelDecryptMalformed exercises the same categories of malformed
// input the sequential reader rejects. The parallel reader resolves the
// last-chunk ambiguity from the shape of the raw stream (read-ahead) rather
// than by a trial decryption, so in adversarial cases the exact error
// message can differ from the sequential reader's -- what must not differ is
// the accept/reject verdict. Where the message is deterministic under the
// new strategy too, it's asserted explicitly.
func TestParallelDecryptMalformed(t *testing.T) {
newCiphertext := func(t *testing.T, key []byte, plaintext []byte) []byte {
t.Helper()
buf := &bytes.Buffer{}
w, err := stream.NewEncryptWriter(key, buf)
if err != nil {
t.Fatal(err)
}
if _, err := w.Write(plaintext); err != nil {
t.Fatal(err)
}
if err := w.Close(); err != nil {
t.Fatal(err)
}
return buf.Bytes()
}
t.Run("wrong key", func(t *testing.T) {
key := randBytes(t, chacha20poly1305.KeySize)
ciphertext := newCiphertext(t, key, randBytes(t, 1000))
wrongKey := randBytes(t, chacha20poly1305.KeySize)
dr, err := stream.NewParallelDecryptReader(wrongKey, bytes.NewReader(ciphertext), 4)
if err != nil {
t.Fatal(err)
}
if _, err := io.ReadAll(dr); err == nil {
t.Fatal("expected error, got nil")
}
})
t.Run("corrupted byte in non-final chunk", func(t *testing.T) {
key := randBytes(t, chacha20poly1305.KeySize)
ciphertext := newCiphertext(t, key, randBytes(t, 2*cs+500))
ciphertext[10] ^= 0xff // inside the first (non-final) chunk
dr, err := stream.NewParallelDecryptReader(key, bytes.NewReader(ciphertext), 4)
if err != nil {
t.Fatal(err)
}
if _, err := io.ReadAll(dr); err == nil {
t.Fatal("expected error, got nil")
}
})
t.Run("truncated", func(t *testing.T) {
key := randBytes(t, chacha20poly1305.KeySize)
ciphertext := newCiphertext(t, key, randBytes(t, 2*cs+500))
truncated := ciphertext[:len(ciphertext)-100]
dr, err := stream.NewParallelDecryptReader(key, bytes.NewReader(truncated), 4)
if err != nil {
t.Fatal(err)
}
if _, err := io.ReadAll(dr); err == nil {
t.Fatal("expected error, got nil")
}
})
t.Run("trailing data appended after short last chunk", func(t *testing.T) {
// With a bytes.Reader, io.ReadFull for the (undersized) chunk buffer
// greedily consumes the real short chunk AND the trailing garbage in
// one read, since everything is available at once: the result is a
// misaligned AEAD tag, not a distinguishable "trailing data" case.
// This is also true of the sequential reader (same io.ReadFull over
// the same fixed-size buffer) -- the verdict, an error, is what must
// hold, not a specific message.
key := randBytes(t, chacha20poly1305.KeySize)
ciphertext := newCiphertext(t, key, randBytes(t, 1000)) // ends in a short chunk
withTrailer := append(append([]byte(nil), ciphertext...), 1, 2, 3, 4, 5)
dr, err := stream.NewParallelDecryptReader(key, bytes.NewReader(withTrailer), 4)
if err != nil {
t.Fatal(err)
}
if _, err := io.ReadAll(dr); err == nil {
t.Fatal("expected error, got nil")
}
})
t.Run("trailing data after full-length last chunk", func(t *testing.T) {
key := randBytes(t, chacha20poly1305.KeySize)
ciphertext := newCiphertext(t, key, randBytes(t, cs)) // exact multiple: full-length last chunk
withTrailer := append(append([]byte(nil), ciphertext...), 1, 2, 3, 4, 5)
dr, err := stream.NewParallelDecryptReader(key, bytes.NewReader(withTrailer), 4)
if err != nil {
t.Fatal(err)
}
// The trailing bytes are re-interpreted as a short "final" chunk here
// (a different, but still safe, rejection path than the sequential
// reader's trailing-byte probe); the verdict must still be an error.
if _, err := io.ReadAll(dr); err == nil {
t.Fatal("expected error, got nil")
}
})
t.Run("empty chunk after a non-empty chunk is rejected", func(t *testing.T) {
key := randBytes(t, chacha20poly1305.KeySize)
aead, err := chacha20poly1305.New(key)
if err != nil {
t.Fatal(err)
}
var malformed []byte
malformed = append(malformed, sealChunkForTest(t, aead, 0, false, randBytes(t, cs))...)
malformed = append(malformed, sealChunkForTest(t, aead, 1, true, nil)...)
dr, err := stream.NewParallelDecryptReader(key, bytes.NewReader(malformed), 4)
if err != nil {
t.Fatal(err)
}
_, err = io.ReadAll(dr)
if err == nil {
t.Fatal("expected error, got nil")
}
if got, want := err.Error(), "last chunk is empty; encrypted payload is malformed"; got != want {
t.Fatalf("error = %q, want %q", got, want)
}
})
}
// sealChunkForTest manually seals a chunk using the same nonce scheme as the
// stream package (a big-endian chunk counter in bytes [3:11], a last-chunk
// flag in the final byte), to construct deliberately malformed streams that
// aren't reachable through the public encrypt API.
func sealChunkForTest(t *testing.T, aead cipher.AEAD, index int64, last bool, plaintext []byte) []byte {
t.Helper()
var nonce [chacha20poly1305.NonceSize]byte
binary.BigEndian.PutUint64(nonce[3:11], uint64(index))
if last {
nonce[len(nonce)-1] = 1
}
return aead.Seal(nil, nonce[:], plaintext, nil)
}
// TestParallelRace exercises the pipeline with oversubscribed workers on a
// multi-chunk payload; run with -race to catch data races in the ordered
// fan-in.
func TestParallelRace(t *testing.T) {
key := randBytes(t, chacha20poly1305.KeySize)
src := randBytes(t, 6*cs+12345)
buf := &bytes.Buffer{}
w, err := stream.NewParallelEncryptWriter(key, buf, runtime.NumCPU()*2)
if err != nil {
t.Fatal(err)
}
if _, err := w.Write(src); err != nil {
t.Fatal(err)
}
if err := w.Close(); err != nil {
t.Fatal(err)
}
dr, err := stream.NewParallelDecryptReader(key, bytes.NewReader(buf.Bytes()), runtime.NumCPU()*2)
if err != nil {
t.Fatal(err)
}
checkRoundTrip(t, dr, src)
}
internal/stream/stream.go
+468
View File
@@ -0,0 +1,468 @@
// SPDX-License-Identifier: GPL-3.0-or-later
// Package stream implements a variant of the STREAM chunked encryption scheme.
//
// The invariants this package exists to hold:
//
// - Counter uniqueness. A chunk's nonce is a pure big-endian counter over
// bytes 3..10, incremented once per chunk and never reset within a
// stream. incNonce panics rather than wrapping, so a (key, nonce) pair
// can never repeat: the counter is 88 bits and the panic is unreachable
// for any real file.
// - Content independence. The nonce depends only on the chunk index and the
// last-chunk flag, never on chunk contents. That is what lets the parallel
// encoder seal chunks out of order and still produce byte-identical
// output.
// - Truncation resistance. The final chunk is sealed under a nonce whose
// last byte carries lastChunkFlag. A truncated stream therefore fails to
// authenticate: the attacker would have to forge a last-chunk tag for a
// chunk the writer sealed as non-final.
// - No trailing data. After a last chunk is accepted, the reader confirms
// the underlying source is at EOF and fails otherwise, so appended bytes
// are rejected rather than silently ignored.
package stream
import (
"bytes"
"crypto/cipher"
"encoding/binary"
"errors"
"fmt"
"io"
"sync/atomic"
"golang.org/x/crypto/chacha20poly1305"
)
const ChunkSize = 64 * 1024
func EncryptedChunkCount(encryptedSize int64) (int64, error) {
chunks := (encryptedSize + encChunkSize - 1) / encChunkSize
plaintextSize := encryptedSize - chunks*chacha20poly1305.Overhead
expChunks := (plaintextSize + ChunkSize - 1) / ChunkSize
// Empty plaintext, the only case that allows (and requires) an empty chunk.
if plaintextSize == 0 {
expChunks = 1
}
if expChunks != chunks {
return 0, fmt.Errorf("invalid encrypted payload size: %d", encryptedSize)
}
return chunks, nil
}
func PlaintextSize(encryptedSize int64) (int64, error) {
chunks, err := EncryptedChunkCount(encryptedSize)
if err != nil {
return 0, err
}
plaintextSize := encryptedSize - chunks*chacha20poly1305.Overhead
return plaintextSize, nil
}
type DecryptReader struct {
a cipher.AEAD
src io.Reader
unread []byte // decrypted but unread data, backed by buf
buf [encChunkSize]byte
err error
nonce [chacha20poly1305.NonceSize]byte
}
const (
encChunkSize = ChunkSize + chacha20poly1305.Overhead
lastChunkFlag = 0x01
)
func NewDecryptReader(key []byte, src io.Reader) (*DecryptReader, error) {
aead, err := chacha20poly1305.New(key)
if err != nil {
return nil, err
}
return &DecryptReader{a: aead, src: src}, nil
}
func (r *DecryptReader) Read(p []byte) (int, error) {
if len(r.unread) > 0 {
n := copy(p, r.unread)
r.unread = r.unread[n:]
return n, nil
}
if r.err != nil {
return 0, r.err
}
if len(p) == 0 {
return 0, nil
}
last, err := r.readChunk()
if err != nil {
r.err = err
return 0, err
}
n := copy(p, r.unread)
r.unread = r.unread[n:]
if last {
// Ensure there is an EOF after the last chunk as expected. In other
// words, check for trailing data after a full-length final chunk.
// Hopefully, the underlying reader supports returning EOF even if it
// had previously returned an EOF to ReadFull.
if _, err := r.src.Read(make([]byte, 1)); err == nil {
r.err = errors.New("trailing data after end of encrypted file")
} else if err != io.EOF {
r.err = fmt.Errorf("non-EOF error reading after end of encrypted file: %w", err)
} else {
r.err = io.EOF
}
}
return n, nil
}
// readChunk reads the next chunk of ciphertext from r.src and makes it available
// in r.unread. last is true if the chunk was marked as the end of the message.
// readChunk must not be called again after returning a last chunk or an error.
func (r *DecryptReader) readChunk() (last bool, err error) {
if len(r.unread) != 0 {
panic("stream: internal error: readChunk called with dirty buffer")
}
in := r.buf[:]
n, err := io.ReadFull(r.src, in)
switch {
case err == io.EOF:
// A message can't end without a marked chunk. This message is truncated.
return false, io.ErrUnexpectedEOF
case err == io.ErrUnexpectedEOF:
// The last chunk can be short, but not empty unless it's the first and
// only chunk.
if !nonceIsZero(&r.nonce) && n == r.a.Overhead() {
return false, errors.New("last chunk is empty; encrypted payload is malformed")
}
in = in[:n]
last = true
setLastChunkFlag(&r.nonce)
case err != nil:
return false, err
}
outBuf := make([]byte, 0, ChunkSize)
out, err := r.a.Open(outBuf, r.nonce[:], in, nil)
if err != nil && !last {
// Check if this was a full-length final chunk.
last = true
setLastChunkFlag(&r.nonce)
out, err = r.a.Open(outBuf, r.nonce[:], in, nil)
}
if err != nil {
return false, errors.New("failed to decrypt and authenticate payload chunk, file may be corrupted or tampered with")
}
incNonce(&r.nonce)
r.unread = r.buf[:copy(r.buf[:], out)]
return last, nil
}
func incNonce(nonce *[chacha20poly1305.NonceSize]byte) {
for i := len(nonce) - 2; i >= 0; i-- {
nonce[i]++
if nonce[i] != 0 {
return
}
}
// The counter is 88 bits, this is unreachable.
panic("stream: chunk counter wrapped around")
}
func nonceForChunk(chunkIndex int64) *[chacha20poly1305.NonceSize]byte {
var nonce [chacha20poly1305.NonceSize]byte
binary.BigEndian.PutUint64(nonce[3:11], uint64(chunkIndex))
return &nonce
}
func setLastChunkFlag(nonce *[chacha20poly1305.NonceSize]byte) {
nonce[len(nonce)-1] = lastChunkFlag
}
func nonceIsZero(nonce *[chacha20poly1305.NonceSize]byte) bool {
return *nonce == [chacha20poly1305.NonceSize]byte{}
}
type EncryptWriter struct {
a cipher.AEAD
dst io.Writer
buf bytes.Buffer
nonce [chacha20poly1305.NonceSize]byte
err error
}
func NewEncryptWriter(key []byte, dst io.Writer) (*EncryptWriter, error) {
aead, err := chacha20poly1305.New(key)
if err != nil {
return nil, err
}
return &EncryptWriter{a: aead, dst: dst}, nil
}
func (w *EncryptWriter) Write(p []byte) (n int, err error) {
if w.err != nil {
return 0, w.err
}
if len(p) == 0 {
return 0, nil
}
total := len(p)
for len(p) > 0 {
n := min(len(p), ChunkSize-w.buf.Len())
w.buf.Write(p[:n])
p = p[n:]
// Only flush if there's a full chunk with bytes still to write, or we
// can't know if this is the last chunk yet.
if w.buf.Len() == ChunkSize && len(p) > 0 {
if err := w.flushChunk(notLastChunk); err != nil {
w.err = err
return 0, err
}
}
}
return total, nil
}
// Close flushes the last chunk. It does not close the underlying Writer.
func (w *EncryptWriter) Close() error {
if w.err != nil {
return w.err
}
w.err = w.flushChunk(lastChunk)
if w.err != nil {
return w.err
}
w.err = errors.New("stream.Writer is already closed")
return nil
}
const (
lastChunk = true
notLastChunk = false
)
func (w *EncryptWriter) flushChunk(last bool) error {
if !last && w.buf.Len() != ChunkSize {
panic("stream: internal error: flush called with partial chunk")
}
if last {
setLastChunkFlag(&w.nonce)
}
w.buf.Grow(chacha20poly1305.Overhead)
ciphertext := w.a.Seal(w.buf.Bytes()[:0], w.nonce[:], w.buf.Bytes(), nil)
_, err := w.dst.Write(ciphertext)
incNonce(&w.nonce)
w.buf.Reset()
return err
}
type EncryptReader struct {
a cipher.AEAD
src io.Reader
// The first ready bytes of buf are already encrypted. This may be less than
// buf.Len(), because we need to over-read to know if a chunk is the last.
ready int
buf bytes.Buffer
nonce [chacha20poly1305.NonceSize]byte
err error
}
func NewEncryptReader(key []byte, src io.Reader) (*EncryptReader, error) {
aead, err := chacha20poly1305.New(key)
if err != nil {
return nil, err
}
return &EncryptReader{a: aead, src: src}, nil
}
func (r *EncryptReader) Read(p []byte) (int, error) {
if r.ready > 0 {
n, err := r.buf.Read(p[:min(len(p), r.ready)])
r.ready -= n
return n, err
}
if r.err != nil {
return 0, r.err
}
if len(p) == 0 {
return 0, nil
}
if err := r.feedBuffer(); err != nil {
r.err = err
return 0, err
}
n, err := r.buf.Read(p[:min(len(p), r.ready)])
r.ready -= n
return n, err
}
// feedBuffer reads and encrypts the next chunk from r.src and appends it to
// r.buf. It sets r.ready to the number of newly available bytes in r.buf.
func (r *EncryptReader) feedBuffer() error {
if r.ready > 0 {
panic("stream: internal error: feedBuffer called with dirty buffer")
}
// CopyN will use r.buf.ReadFrom/WriteTo to fill the buffer directly.
// We need ChunkSize + 1 bytes to determine if this is the last chunk.
_, err := io.CopyN(&r.buf, r.src, int64(ChunkSize-r.buf.Len()+1))
if err != nil && err != io.EOF {
return err
}
if last := r.buf.Len() <= ChunkSize; last {
setLastChunkFlag(&r.nonce)
// After Grow, we know r.buf.Bytes() has enough capacity for the
// overhead. We encrypt in place and then do a Write to include the
// overhead in the buffer.
r.buf.Grow(chacha20poly1305.Overhead)
plaintext := r.buf.Bytes()
r.a.Seal(plaintext[:0], r.nonce[:], plaintext, nil)
incNonce(&r.nonce)
r.buf.Write(plaintext[len(plaintext) : len(plaintext)+chacha20poly1305.Overhead])
r.ready = r.buf.Len()
r.err = io.EOF
return nil
}
// Same, but accounting for the tail byte which will remain unencrypted and
// needs to be shifted past the overhead.
if r.buf.Len() != ChunkSize+1 {
panic("stream: internal error: unexpected buffer length")
}
tailByte := r.buf.Bytes()[ChunkSize]
r.buf.Grow(chacha20poly1305.Overhead)
plaintext := r.buf.Bytes()[:ChunkSize]
r.a.Seal(plaintext[:0], r.nonce[:], plaintext, nil)
incNonce(&r.nonce)
r.buf.Write(plaintext[len(plaintext)+1 : len(plaintext)+chacha20poly1305.Overhead])
r.buf.WriteByte(tailByte)
r.ready = ChunkSize + chacha20poly1305.Overhead
return nil
}
type DecryptReaderAt struct {
a cipher.AEAD
src io.ReaderAt
size int64
chunks int64
cache atomic.Pointer[cachedChunk]
}
type cachedChunk struct {
off int64
data []byte
}
func NewDecryptReaderAt(key []byte, src io.ReaderAt, size int64) (*DecryptReaderAt, error) {
aead, err := chacha20poly1305.New(key)
if err != nil {
return nil, err
}
// Check that size is valid by decrypting the final chunk.
chunks, err := EncryptedChunkCount(size)
if err != nil {
return nil, err
}
finalChunkIndex := chunks - 1
finalChunkOff := finalChunkIndex * encChunkSize
finalChunkSize := size - finalChunkOff
finalChunk := make([]byte, finalChunkSize)
if _, err := src.ReadAt(finalChunk, finalChunkOff); err != nil {
return nil, fmt.Errorf("failed to read final chunk: %w", err)
}
nonce := nonceForChunk(finalChunkIndex)
setLastChunkFlag(nonce)
plaintext, err := aead.Open(finalChunk[:0], nonce[:], finalChunk, nil)
if err != nil {
return nil, fmt.Errorf("failed to decrypt and authenticate final chunk: %w", err)
}
cache := &cachedChunk{off: finalChunkOff, data: plaintext}
plaintextSize := size - chunks*chacha20poly1305.Overhead
r := &DecryptReaderAt{a: aead, src: src, size: plaintextSize, chunks: chunks}
r.cache.Store(cache)
return r, nil
}
func (r *DecryptReaderAt) ReadAt(p []byte, off int64) (n int, err error) {
if off < 0 || off > r.size {
return 0, fmt.Errorf("offset out of range [0:%d]: %d", r.size, off)
}
if len(p) == 0 {
return 0, nil
}
var cacheUpdate *cachedChunk
chunk := make([]byte, encChunkSize)
for len(p) > 0 && off < r.size {
chunkIndex := off / ChunkSize
chunkOff := chunkIndex * encChunkSize
encSize := r.size + r.chunks*chacha20poly1305.Overhead
chunkSize := min(encSize-chunkOff, encChunkSize)
cached := r.cache.Load()
var plaintext []byte
if cached != nil && cached.off == chunkOff {
plaintext = cached.data
cacheUpdate = nil
} else {
nn, err := r.src.ReadAt(chunk[:chunkSize], chunkOff)
if err == io.EOF {
if int64(nn) != chunkSize {
err = io.ErrUnexpectedEOF
} else {
err = nil
}
}
if err != nil {
return n, fmt.Errorf("failed to read chunk at offset %d: %w", chunkOff, err)
}
nonce := nonceForChunk(chunkIndex)
if chunkIndex == r.chunks-1 {
setLastChunkFlag(nonce)
}
plaintext, err = r.a.Open(chunk[:0], nonce[:], chunk[:chunkSize], nil)
if err != nil {
return n, fmt.Errorf("failed to decrypt and authenticate chunk at offset %d: %w", chunkOff, err)
}
cacheUpdate = &cachedChunk{off: chunkOff, data: plaintext}
}
plainChunkOff := int(off - chunkIndex*ChunkSize)
copySize := min(len(plaintext)-plainChunkOff, len(p))
copy(p, plaintext[plainChunkOff:plainChunkOff+copySize])
p = p[copySize:]
off += int64(copySize)
n += copySize
}
if cacheUpdate != nil {
r.cache.Store(cacheUpdate)
}
if off == r.size {
return n, io.EOF
}
return n, nil
}
internal/stream/stream_test.go
+950
View File
@@ -0,0 +1,950 @@
// SPDX-License-Identifier: GPL-3.0-or-later
package stream_test
import (
"bytes"
"crypto/rand"
"fmt"
"io"
"testing"
"testing/iotest"
"github.com/andydixon/vault/internal/stream"
"golang.org/x/crypto/chacha20poly1305"
)
const cs = stream.ChunkSize
func TestRoundTrip(t *testing.T) {
for _, length := range []int{0, 1000, cs - 1, cs, cs + 1, cs + 100, 2 * cs, 2*cs + 500} {
for _, stepSize := range []int{512, 600, 1000, cs - 1, cs, cs + 1} {
t.Run(fmt.Sprintf("len=%d,step=%d", length, stepSize), func(t *testing.T) {
testRoundTrip(t, stepSize, length)
})
}
}
length, stepSize := 2*cs+500, 1
t.Run(fmt.Sprintf("len=%d,step=%d", length, stepSize), func(t *testing.T) {
testRoundTrip(t, stepSize, length)
})
}
func testRoundTrip(t *testing.T, stepSize, length int) {
src := make([]byte, length)
if _, err := rand.Read(src); err != nil {
t.Fatal(err)
}
key := make([]byte, chacha20poly1305.KeySize)
if _, err := rand.Read(key); err != nil {
t.Fatal(err)
}
var ciphertext []byte
t.Run("EncryptWriter", func(t *testing.T) {
buf := &bytes.Buffer{}
w, err := stream.NewEncryptWriter(key, buf)
if err != nil {
t.Fatal(err)
}
var n int
for n < length {
b := min(length-n, stepSize)
nn, err := w.Write(src[n : n+b])
if err != nil {
t.Fatal(err)
}
if nn != b {
t.Errorf("Write returned %d, expected %d", nn, b)
}
n += nn
nn, err = w.Write(src[n:n])
if err != nil {
t.Fatal(err)
}
if nn != 0 {
t.Errorf("Write returned %d, expected 0", nn)
}
}
if err := w.Close(); err != nil {
t.Error("Close returned an error:", err)
}
ciphertext = buf.Bytes()
})
t.Run("DecryptReader", func(t *testing.T) {
r, err := stream.NewDecryptReader(key, bytes.NewReader(ciphertext))
if err != nil {
t.Fatal(err)
}
var n int
readBuf := make([]byte, stepSize)
for n < length {
nn, err := r.Read(readBuf)
if err != nil {
t.Fatalf("Read error at index %d: %v", n, err)
}
if !bytes.Equal(readBuf[:nn], src[n:n+nn]) {
t.Errorf("wrong data at indexes %d - %d", n, n+nn)
}
n += nn
}
t.Run("TestReader", func(t *testing.T) {
if length > 1000 && testing.Short() {
t.Skip("skipping slow iotest.TestReader on long input")
}
r, _ := stream.NewDecryptReader(key, bytes.NewReader(ciphertext))
if err := iotest.TestReader(r, src); err != nil {
t.Error("iotest.TestReader error on DecryptReader:", err)
}
})
})
t.Run("DecryptReaderAt", func(t *testing.T) {
rAt, err := stream.NewDecryptReaderAt(key, bytes.NewReader(ciphertext), int64(len(ciphertext)))
if err != nil {
t.Fatal(err)
}
rr := io.NewSectionReader(rAt, 0, int64(len(ciphertext)))
var n int
readBuf := make([]byte, stepSize)
for n < length {
nn, err := rr.Read(readBuf)
if n+nn == length && err == io.EOF {
err = nil
}
if err != nil {
t.Fatalf("ReadAt error at index %d: %v", n, err)
}
if !bytes.Equal(readBuf[:nn], src[n:n+nn]) {
t.Errorf("wrong data at indexes %d - %d", n, n+nn)
}
n += nn
}
t.Run("TestReader", func(t *testing.T) {
if length > 1000 && testing.Short() {
t.Skip("skipping slow iotest.TestReader on long input")
}
rr := io.NewSectionReader(rAt, 0, int64(len(src)))
if err := iotest.TestReader(rr, src); err != nil {
t.Error("iotest.TestReader error on DecryptReaderAt:", err)
}
})
})
t.Run("EncryptReader", func(t *testing.T) {
er, err := stream.NewEncryptReader(key, bytes.NewReader(src))
if err != nil {
t.Fatal(err)
}
var n int
readBuf := make([]byte, stepSize)
for {
nn, err := er.Read(readBuf)
if nn == 0 && err == io.EOF {
break
} else if err != nil {
t.Fatalf("EncryptReader Read error at index %d: %v", n, err)
}
if !bytes.Equal(readBuf[:nn], ciphertext[n:n+nn]) {
t.Errorf("EncryptReader wrong data at indexes %d - %d", n, n+nn)
}
n += nn
}
if n != len(ciphertext) {
t.Errorf("EncryptReader read %d bytes, expected %d", n, len(ciphertext))
}
t.Run("TestReader", func(t *testing.T) {
if length > 1000 && testing.Short() {
t.Skip("skipping slow iotest.TestReader on long input")
}
er, _ := stream.NewEncryptReader(key, bytes.NewReader(src))
if err := iotest.TestReader(er, ciphertext); err != nil {
t.Error("iotest.TestReader error on EncryptReader:", err)
}
})
})
}
// trackingReaderAt wraps an io.ReaderAt and tracks whether ReadAt was called.
type trackingReaderAt struct {
r io.ReaderAt
called bool
}
func (t *trackingReaderAt) ReadAt(p []byte, off int64) (int, error) {
t.called = true
return t.r.ReadAt(p, off)
}
func (t *trackingReaderAt) reset() {
t.called = false
}
func TestDecryptReaderAt(t *testing.T) {
key := make([]byte, chacha20poly1305.KeySize)
if _, err := rand.Read(key); err != nil {
t.Fatal(err)
}
// Create plaintext spanning exactly 3 chunks: 2 full chunks + partial third
// Chunk 0: [0, cs)
// Chunk 1: [cs, 2*cs)
// Chunk 2: [2*cs, 2*cs+500)
plaintextSize := 2*cs + 500
plaintext := make([]byte, plaintextSize)
if _, err := rand.Read(plaintext); err != nil {
t.Fatal(err)
}
// Encrypt
buf := &bytes.Buffer{}
w, err := stream.NewEncryptWriter(key, buf)
if err != nil {
t.Fatal(err)
}
if _, err := w.Write(plaintext); err != nil {
t.Fatal(err)
}
if err := w.Close(); err != nil {
t.Fatal(err)
}
ciphertext := buf.Bytes()
// Create tracking ReaderAt
tracker := &trackingReaderAt{r: bytes.NewReader(ciphertext)}
// Create DecryptReaderAt (this reads and caches the final chunk)
ra, err := stream.NewDecryptReaderAt(key, tracker, int64(len(ciphertext)))
if err != nil {
t.Fatal(err)
}
tracker.reset()
// Helper to check reads
checkRead := func(name string, off int64, size int, wantN int, wantEOF bool, wantSrcRead bool) {
t.Helper()
tracker.reset()
p := make([]byte, size)
n, err := ra.ReadAt(p, off)
if wantEOF {
if err != io.EOF {
t.Errorf("%s: got err=%v, want EOF", name, err)
}
} else {
if err != nil {
t.Errorf("%s: got err=%v, want nil", name, err)
}
}
if n != wantN {
t.Errorf("%s: got n=%d, want %d", name, n, wantN)
}
if tracker.called != wantSrcRead {
t.Errorf("%s: src.ReadAt called=%v, want %v", name, tracker.called, wantSrcRead)
}
// Verify data correctness
if n > 0 && off >= 0 && off < int64(plaintextSize) {
end := int(off) + n
if end > plaintextSize {
end = plaintextSize
}
if !bytes.Equal(p[:n], plaintext[off:end]) {
t.Errorf("%s: data mismatch", name)
}
}
}
// Test 1: Read from final chunk (cached by constructor)
checkRead("final chunk (cached)", int64(2*cs+100), 100, 100, false, false)
// Test 2: Read spanning second and third chunk
checkRead("span chunks 1-2", int64(cs+cs-50), 100, 100, false, true)
// Test 3: Read from final chunk again (cached from test 2)
// When reading across chunks 1-2 in test 2, the loop processes chunk 1 then chunk 2,
// so chunk 2 ends up in the cache.
checkRead("final chunk after span", int64(2*cs+200), 100, 100, false, false)
// Test 4: Read from final chunk again (now cached)
checkRead("final chunk (cached again)", int64(2*cs+50), 50, 50, false, false)
// Test 5: Read from first chunk (not cached)
checkRead("first chunk", 0, 100, 100, false, true)
// Test 6: Read from first chunk again (now cached)
checkRead("first chunk (cached)", 50, 100, 100, false, false)
// Test 7: Read spanning all chunks
tracker.reset()
p := make([]byte, plaintextSize)
n, err := ra.ReadAt(p, 0)
if err != io.EOF {
t.Errorf("span all: got err=%v, want EOF", err)
}
if n != plaintextSize {
t.Errorf("span all: got n=%d, want %d", n, plaintextSize)
}
if !bytes.Equal(p, plaintext) {
t.Errorf("span all: data mismatch")
}
// Test 8: Read beyond the end (offset > size)
tracker.reset()
p = make([]byte, 100)
n, err = ra.ReadAt(p, int64(plaintextSize+100))
if err == nil {
t.Error("beyond end: expected error, got nil")
}
if n != 0 {
t.Errorf("beyond end: got n=%d, want 0", n)
}
// Test 9: Read with off = size (should return 0, EOF)
tracker.reset()
p = make([]byte, 100)
n, err = ra.ReadAt(p, int64(plaintextSize))
if err != io.EOF {
t.Errorf("off=size: got err=%v, want EOF", err)
}
if n != 0 {
t.Errorf("off=size: got n=%d, want 0", n)
}
// Test 10: Read spanning last chunk and beyond
tracker.reset()
p = make([]byte, 1000) // request more than available
n, err = ra.ReadAt(p, int64(2*cs+400))
if err != io.EOF {
t.Errorf("span last+beyond: got err=%v, want EOF", err)
}
wantN := 500 - 400 // only 100 bytes available from offset 2*cs+400
if n != wantN {
t.Errorf("span last+beyond: got n=%d, want %d", n, wantN)
}
if !bytes.Equal(p[:n], plaintext[2*cs+400:]) {
t.Error("span last+beyond: data mismatch")
}
// Test 11: Read spanning second+last chunk and beyond
tracker.reset()
p = make([]byte, cs+1000) // request more than available
n, err = ra.ReadAt(p, int64(cs+100))
if err != io.EOF {
t.Errorf("span 1-2+beyond: got err=%v, want EOF", err)
}
wantN = plaintextSize - (cs + 100)
if n != wantN {
t.Errorf("span 1-2+beyond: got n=%d, want %d", n, wantN)
}
if !bytes.Equal(p[:n], plaintext[cs+100:]) {
t.Error("span 1-2+beyond: data mismatch")
}
// Test 12: Negative offset
tracker.reset()
p = make([]byte, 100)
n, err = ra.ReadAt(p, -1)
if err == nil {
t.Error("negative offset: expected error, got nil")
}
if n != 0 {
t.Errorf("negative offset: got n=%d, want 0", n)
}
// Test 13: Zero-length read in the middle
tracker.reset()
p = make([]byte, 0)
n, err = ra.ReadAt(p, 100)
if err != nil {
t.Errorf("zero-length middle: got err=%v, want nil", err)
}
if n != 0 {
t.Errorf("zero-length middle: got n=%d, want 0", n)
}
// Test 14: Zero-length read at end
tracker.reset()
p = make([]byte, 0)
n, err = ra.ReadAt(p, int64(plaintextSize))
if err != nil {
t.Errorf("zero-length end: got err=%v, want nil", err)
}
if n != 0 {
t.Errorf("zero-length end: got n=%d, want 0", n)
}
// Test 15: Read exactly one chunk at chunk boundary
checkRead("exact chunk at boundary", int64(cs), cs, cs, false, true)
// Test 16: Read one byte at each chunk boundary
checkRead("one byte at start", 0, 1, 1, false, true)
checkRead("one byte at cs-1", int64(cs-1), 1, 1, false, false) // cached from test 15
checkRead("one byte at cs", int64(cs), 1, 1, false, true)
checkRead("one byte at 2*cs-1", int64(2*cs-1), 1, 1, false, false) // same chunk
checkRead("one byte at 2*cs", int64(2*cs), 1, 1, false, true)
checkRead("last byte", int64(plaintextSize-1), 1, 1, true, false) // same chunk, EOF because we reach end
// Test 17: Read crossing exactly one chunk boundary
checkRead("cross boundary 0-1", int64(cs-50), 100, 100, false, true)
checkRead("cross boundary 1-2", int64(2*cs-50), 100, 100, false, true)
}
func TestDecryptReaderAtEmpty(t *testing.T) {
key := make([]byte, chacha20poly1305.KeySize)
if _, err := rand.Read(key); err != nil {
t.Fatal(err)
}
// Create empty encrypted file
buf := &bytes.Buffer{}
w, err := stream.NewEncryptWriter(key, buf)
if err != nil {
t.Fatal(err)
}
if err := w.Close(); err != nil {
t.Fatal(err)
}
ciphertext := buf.Bytes()
tracker := &trackingReaderAt{r: bytes.NewReader(ciphertext)}
ra, err := stream.NewDecryptReaderAt(key, tracker, int64(len(ciphertext)))
if err != nil {
t.Fatal(err)
}
tracker.reset()
// Test 1: Read from empty file at offset 0
p := make([]byte, 100)
n, err := ra.ReadAt(p, 0)
if err != io.EOF {
t.Errorf("empty read: got err=%v, want EOF", err)
}
if n != 0 {
t.Errorf("empty read: got n=%d, want 0", n)
}
// Test 2: Zero-length read from empty file
p = make([]byte, 0)
n, err = ra.ReadAt(p, 0)
if err != nil {
t.Errorf("empty zero-length: got err=%v, want nil", err)
}
if n != 0 {
t.Errorf("empty zero-length: got n=%d, want 0", n)
}
// Test 3: Read beyond empty file
p = make([]byte, 100)
n, err = ra.ReadAt(p, 1)
if err == nil {
t.Error("empty beyond: expected error, got nil")
}
if n != 0 {
t.Errorf("empty beyond: got n=%d, want 0", n)
}
}
func TestDecryptReaderAtSingleChunk(t *testing.T) {
key := make([]byte, chacha20poly1305.KeySize)
if _, err := rand.Read(key); err != nil {
t.Fatal(err)
}
// Single chunk, not full
plaintext := make([]byte, 1000)
if _, err := rand.Read(plaintext); err != nil {
t.Fatal(err)
}
buf := &bytes.Buffer{}
w, err := stream.NewEncryptWriter(key, buf)
if err != nil {
t.Fatal(err)
}
if _, err := w.Write(plaintext); err != nil {
t.Fatal(err)
}
if err := w.Close(); err != nil {
t.Fatal(err)
}
ciphertext := buf.Bytes()
tracker := &trackingReaderAt{r: bytes.NewReader(ciphertext)}
ra, err := stream.NewDecryptReaderAt(key, tracker, int64(len(ciphertext)))
if err != nil {
t.Fatal(err)
}
tracker.reset()
// All reads should use cache (final chunk = only chunk)
p := make([]byte, 100)
n, err := ra.ReadAt(p, 0)
if err != nil {
t.Errorf("single chunk start: got err=%v, want nil", err)
}
if n != 100 {
t.Errorf("single chunk start: got n=%d, want 100", n)
}
if tracker.called {
t.Error("single chunk start: unexpected src.ReadAt call")
}
if !bytes.Equal(p[:n], plaintext[:100]) {
t.Error("single chunk start: data mismatch")
}
// Read at end
n, err = ra.ReadAt(p, 900)
if err != io.EOF {
t.Errorf("single chunk end: got err=%v, want EOF", err)
}
if n != 100 {
t.Errorf("single chunk end: got n=%d, want 100", n)
}
if tracker.called {
t.Error("single chunk end: unexpected src.ReadAt call")
}
if !bytes.Equal(p[:n], plaintext[900:]) {
t.Error("single chunk end: data mismatch")
}
}
func TestDecryptReaderAtFullChunks(t *testing.T) {
key := make([]byte, chacha20poly1305.KeySize)
if _, err := rand.Read(key); err != nil {
t.Fatal(err)
}
// Exactly 2 full chunks
plaintext := make([]byte, 2*cs)
if _, err := rand.Read(plaintext); err != nil {
t.Fatal(err)
}
buf := &bytes.Buffer{}
w, err := stream.NewEncryptWriter(key, buf)
if err != nil {
t.Fatal(err)
}
if _, err := w.Write(plaintext); err != nil {
t.Fatal(err)
}
if err := w.Close(); err != nil {
t.Fatal(err)
}
ciphertext := buf.Bytes()
tracker := &trackingReaderAt{r: bytes.NewReader(ciphertext)}
ra, err := stream.NewDecryptReaderAt(key, tracker, int64(len(ciphertext)))
if err != nil {
t.Fatal(err)
}
tracker.reset()
// Read last byte of second chunk (cached)
p := make([]byte, 1)
n, err := ra.ReadAt(p, int64(2*cs-1))
if err != io.EOF {
t.Errorf("last byte: got err=%v, want EOF", err)
}
if n != 1 {
t.Errorf("last byte: got n=%d, want 1", n)
}
if tracker.called {
t.Error("last byte: unexpected src.ReadAt call (should be cached)")
}
if p[0] != plaintext[2*cs-1] {
t.Error("last byte: data mismatch")
}
// Read at exactly the boundary between chunks
p = make([]byte, 100)
n, err = ra.ReadAt(p, int64(cs-50))
if err != nil {
t.Errorf("boundary: got err=%v, want nil", err)
}
if n != 100 {
t.Errorf("boundary: got n=%d, want 100", n)
}
if !bytes.Equal(p, plaintext[cs-50:cs+50]) {
t.Error("boundary: data mismatch")
}
}
func TestDecryptReaderAtWrongKey(t *testing.T) {
key := make([]byte, chacha20poly1305.KeySize)
if _, err := rand.Read(key); err != nil {
t.Fatal(err)
}
plaintext := make([]byte, 1000)
if _, err := rand.Read(plaintext); err != nil {
t.Fatal(err)
}
buf := &bytes.Buffer{}
w, err := stream.NewEncryptWriter(key, buf)
if err != nil {
t.Fatal(err)
}
if _, err := w.Write(plaintext); err != nil {
t.Fatal(err)
}
if err := w.Close(); err != nil {
t.Fatal(err)
}
ciphertext := buf.Bytes()
// Try to decrypt with wrong key
wrongKey := make([]byte, chacha20poly1305.KeySize)
if _, err := rand.Read(wrongKey); err != nil {
t.Fatal(err)
}
_, err = stream.NewDecryptReaderAt(wrongKey, bytes.NewReader(ciphertext), int64(len(ciphertext)))
if err == nil {
t.Error("wrong key: expected error, got nil")
}
}
func TestDecryptReaderAtInvalidSize(t *testing.T) {
key := make([]byte, chacha20poly1305.KeySize)
if _, err := rand.Read(key); err != nil {
t.Fatal(err)
}
plaintext := make([]byte, 1000)
if _, err := rand.Read(plaintext); err != nil {
t.Fatal(err)
}
buf := &bytes.Buffer{}
w, err := stream.NewEncryptWriter(key, buf)
if err != nil {
t.Fatal(err)
}
if _, err := w.Write(plaintext); err != nil {
t.Fatal(err)
}
if err := w.Close(); err != nil {
t.Fatal(err)
}
ciphertext := buf.Bytes()
// Wrong size (too small)
_, err = stream.NewDecryptReaderAt(key, bytes.NewReader(ciphertext), int64(len(ciphertext)-1))
if err == nil {
t.Error("wrong size (small): expected error, got nil")
}
// Wrong size (too large)
_, err = stream.NewDecryptReaderAt(key, bytes.NewReader(ciphertext), int64(len(ciphertext)+1))
if err == nil {
t.Error("wrong size (large): expected error, got nil")
}
// Size that would imply empty final chunk (invalid)
// This would be: one full encrypted chunk + just overhead
invalidSize := int64(cs + chacha20poly1305.Overhead + chacha20poly1305.Overhead)
_, err = stream.NewDecryptReaderAt(key, bytes.NewReader(make([]byte, invalidSize)), invalidSize)
if err == nil {
t.Error("invalid size (empty final chunk): expected error, got nil")
}
}
func TestDecryptReaderAtTruncated(t *testing.T) {
key := make([]byte, chacha20poly1305.KeySize)
if _, err := rand.Read(key); err != nil {
t.Fatal(err)
}
plaintext := make([]byte, 2*cs+500)
if _, err := rand.Read(plaintext); err != nil {
t.Fatal(err)
}
buf := &bytes.Buffer{}
w, err := stream.NewEncryptWriter(key, buf)
if err != nil {
t.Fatal(err)
}
if _, err := w.Write(plaintext); err != nil {
t.Fatal(err)
}
if err := w.Close(); err != nil {
t.Fatal(err)
}
ciphertext := buf.Bytes()
// Truncate ciphertext but lie about size
truncated := ciphertext[:len(ciphertext)-100]
_, err = stream.NewDecryptReaderAt(key, bytes.NewReader(truncated), int64(len(ciphertext)))
if err == nil {
t.Error("truncated: expected error, got nil")
}
}
func TestDecryptReaderAtTruncatedChunk(t *testing.T) {
key := make([]byte, chacha20poly1305.KeySize)
if _, err := rand.Read(key); err != nil {
t.Fatal(err)
}
// Create 4 chunks: 3 full + 1 partial
plaintext := make([]byte, 3*cs+500)
if _, err := rand.Read(plaintext); err != nil {
t.Fatal(err)
}
buf := &bytes.Buffer{}
w, err := stream.NewEncryptWriter(key, buf)
if err != nil {
t.Fatal(err)
}
if _, err := w.Write(plaintext); err != nil {
t.Fatal(err)
}
if err := w.Close(); err != nil {
t.Fatal(err)
}
ciphertext := buf.Bytes()
// Truncate to 3 chunks (remove the actual final chunk)
// The third chunk was NOT encrypted with the last chunk flag,
// so decryption should fail when we try to use it as the final chunk.
encChunkSize := cs + 16 // ChunkSize + Overhead
truncatedSize := int64(3 * encChunkSize)
truncated := ciphertext[:truncatedSize]
_, err = stream.NewDecryptReaderAt(key, bytes.NewReader(truncated), truncatedSize)
if err == nil {
t.Error("truncated at chunk boundary: expected error, got nil")
}
}
func TestDecryptReaderAtConcurrent(t *testing.T) {
key := make([]byte, chacha20poly1305.KeySize)
if _, err := rand.Read(key); err != nil {
t.Fatal(err)
}
// Create plaintext spanning 3 chunks: 2 full + partial
plaintextSize := 2*cs + 500
plaintext := make([]byte, plaintextSize)
if _, err := rand.Read(plaintext); err != nil {
t.Fatal(err)
}
// Encrypt
buf := &bytes.Buffer{}
w, err := stream.NewEncryptWriter(key, buf)
if err != nil {
t.Fatal(err)
}
if _, err := w.Write(plaintext); err != nil {
t.Fatal(err)
}
if err := w.Close(); err != nil {
t.Fatal(err)
}
ciphertext := buf.Bytes()
ra, err := stream.NewDecryptReaderAt(key, bytes.NewReader(ciphertext), int64(len(ciphertext)))
if err != nil {
t.Fatal(err)
}
t.Run("same chunk", func(t *testing.T) {
t.Parallel()
const goroutines = 10
const iterations = 100
errc := make(chan error, goroutines)
for g := range goroutines {
go func(id int) {
for i := range iterations {
off := int64((id*iterations + i) % 500)
p := make([]byte, 100)
n, err := ra.ReadAt(p, off)
if err != nil {
errc <- fmt.Errorf("goroutine %d iter %d: %v", id, i, err)
return
}
if n != 100 {
errc <- fmt.Errorf("goroutine %d iter %d: n=%d, want 100", id, i, n)
return
}
if !bytes.Equal(p, plaintext[off:off+100]) {
errc <- fmt.Errorf("goroutine %d iter %d: data mismatch", id, i)
return
}
}
errc <- nil
}(g)
}
for range goroutines {
if err := <-errc; err != nil {
t.Error(err)
}
}
})
t.Run("different chunks", func(t *testing.T) {
t.Parallel()
const goroutines = 10
const iterations = 100
errc := make(chan error, goroutines)
for g := range goroutines {
go func(id int) {
for i := range iterations {
// Each goroutine reads from a different chunk based on id
chunkIdx := id % 3
off := int64(chunkIdx*cs + (i % 400))
size := 100
if off+int64(size) > int64(plaintextSize) {
size = plaintextSize - int(off)
}
p := make([]byte, size)
n, err := ra.ReadAt(p, off)
if n == size && err == io.EOF {
err = nil // EOF at end is acceptable
}
if err != nil {
errc <- fmt.Errorf("goroutine %d iter %d: off=%d: %v", id, i, off, err)
return
}
if n != size {
errc <- fmt.Errorf("goroutine %d iter %d: n=%d, want %d", id, i, n, size)
return
}
if !bytes.Equal(p[:n], plaintext[off:off+int64(n)]) {
errc <- fmt.Errorf("goroutine %d iter %d: data mismatch", id, i)
return
}
}
errc <- nil
}(g)
}
for range goroutines {
if err := <-errc; err != nil {
t.Error(err)
}
}
})
t.Run("across chunks", func(t *testing.T) {
t.Parallel()
const goroutines = 10
const iterations = 100
errc := make(chan error, goroutines)
for g := range goroutines {
go func(id int) {
for i := range iterations {
// Read across chunk boundaries
boundary := (id%2 + 1) * cs // either cs or 2*cs
off := int64(boundary - 50 + (i % 30))
size := 100
if off+int64(size) > int64(plaintextSize) {
size = plaintextSize - int(off)
}
if size <= 0 {
continue
}
p := make([]byte, size)
n, err := ra.ReadAt(p, off)
if n == size && err == io.EOF {
err = nil
}
if err != nil {
errc <- fmt.Errorf("goroutine %d iter %d: off=%d size=%d: %v", id, i, off, size, err)
return
}
if n != size {
errc <- fmt.Errorf("goroutine %d iter %d: n=%d, want %d", id, i, n, size)
return
}
if !bytes.Equal(p[:n], plaintext[off:off+int64(n)]) {
errc <- fmt.Errorf("goroutine %d iter %d: data mismatch", id, i)
return
}
}
errc <- nil
}(g)
}
for range goroutines {
if err := <-errc; err != nil {
t.Error(err)
}
}
})
}
func TestDecryptReaderAtCorrupted(t *testing.T) {
key := make([]byte, chacha20poly1305.KeySize)
if _, err := rand.Read(key); err != nil {
t.Fatal(err)
}
plaintext := make([]byte, 2*cs+500)
if _, err := rand.Read(plaintext); err != nil {
t.Fatal(err)
}
buf := &bytes.Buffer{}
w, err := stream.NewEncryptWriter(key, buf)
if err != nil {
t.Fatal(err)
}
if _, err := w.Write(plaintext); err != nil {
t.Fatal(err)
}
if err := w.Close(); err != nil {
t.Fatal(err)
}
ciphertext := bytes.Clone(buf.Bytes())
// Corrupt final chunk - should fail in constructor
corruptedFinal := bytes.Clone(ciphertext)
corruptedFinal[len(corruptedFinal)-10] ^= 0xFF
_, err = stream.NewDecryptReaderAt(key, bytes.NewReader(corruptedFinal), int64(len(corruptedFinal)))
if err == nil {
t.Error("corrupted final: expected error, got nil")
}
// Corrupt first chunk - should fail on read
corruptedFirst := bytes.Clone(ciphertext)
corruptedFirst[10] ^= 0xFF
ra, err := stream.NewDecryptReaderAt(key, bytes.NewReader(corruptedFirst), int64(len(corruptedFirst)))
if err != nil {
t.Fatalf("corrupted first constructor: unexpected error: %v", err)
}
p := make([]byte, 100)
_, err = ra.ReadAt(p, 0)
if err == nil {
t.Error("corrupted first read: expected error, got nil")
}
}
internal/term/term.go
+89
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package term
import (
"fmt"
"os"
"runtime"
"golang.org/x/term"
)
// enableVirtualTerminalProcessing tries to enable virtual terminal processing
// on Windows. If it fails, avoid using escape sequences to prevent weird
// characters being printed to the console.
var enableVirtualTerminalProcessing func(out *os.File) error
// clearLine clears the current line on the terminal, or opens a new line if
// terminal escape codes don't work.
func clearLine(out *os.File) {
const (
CUI = "\033[" // Control Sequence Introducer
CPL = CUI + "F" // Cursor Previous Line
EL = CUI + "K" // Erase in Line
)
// First, open a new line, which is guaranteed to work everywhere. Then, try
// to erase the line above with escape codes, if possible.
//
// (We use CRLF instead of LF to work around an apparent bug in WSL2's
// handling of CONOUT$. Only when running a Windows binary from WSL2, the
// cursor would not go back to the start of the line with a simple LF.
// Honestly, it's impressive CONIN$ and CONOUT$ work at all inside WSL2.)
fmt.Fprintf(out, "\r\n")
if enableVirtualTerminalProcessing == nil || enableVirtualTerminalProcessing(out) == nil {
fmt.Fprintf(out, CPL+EL)
}
}
// WithTerminal runs f with the terminal input and output files, if available.
// WithTerminal does not open a non-terminal stdin, so the caller does not need
// to check if stdin is in use.
func WithTerminal(f func(in, out *os.File) error) error {
if runtime.GOOS == "windows" {
in, err := os.OpenFile("CONIN$", os.O_RDWR, 0)
if err != nil {
return err
}
defer in.Close()
out, err := os.OpenFile("CONOUT$", os.O_WRONLY, 0)
if err != nil {
return err
}
defer out.Close()
return f(in, out)
} else if tty, err := os.OpenFile("/dev/tty", os.O_RDWR, 0); err == nil {
defer tty.Close()
return f(tty, tty)
} else if term.IsTerminal(int(os.Stdin.Fd())) {
return f(os.Stdin, os.Stdin)
} else {
return fmt.Errorf("standard input is not a terminal, and /dev/tty is not available: %v", err)
}
}
// ReadSecret reads a value from the terminal with no echo. The prompt is ephemeral.
func ReadSecret(prompt string) (s []byte, err error) {
err = WithTerminal(func(in, out *os.File) error {
fmt.Fprintf(out, "%s ", prompt)
defer clearLine(out)
s, err = term.ReadPassword(int(in.Fd()))
return err
})
return
}
// ReadPassphrase returns the passphrase from the environment variable env if
// it is set, otherwise prompts on the terminal.
func ReadPassphrase(prompt, env string) (string, error) {
if p, ok := os.LookupEnv(env); ok {
if p == "" {
return "", fmt.Errorf("%s is set but empty", env)
}
return p, nil
}
p, err := ReadSecret(prompt)
if err != nil {
return "", fmt.Errorf("could not read passphrase (set %s for non-interactive use): %v", env, err)
}
return string(p), nil
}
internal/term/term_windows.go
+46
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@@ -0,0 +1,46 @@
// SPDX-License-Identifier: GPL-3.0-or-later
package term
import (
"errors"
"os"
"syscall"
"golang.org/x/sys/windows"
)
func init() {
enableVirtualTerminalProcessing = func(out *os.File) error {
// Some instances of the Windows Console (e.g., cmd.exe and Windows PowerShell)
// do not have the virtual terminal processing enabled, which is necessary to
// make terminal escape sequences work. For this reason the clearLine function
// may not properly work. Here we enable the virtual terminal processing, if
// possible.
//
// See https://learn.microsoft.com/en-us/windows/console/console-virtual-terminal-sequences.
const (
ENABLE_PROCESSED_OUTPUT uint32 = 0x1
ENABLE_VIRTUAL_TERMINAL_PROCESSING uint32 = 0x4
)
kernel32DLL := windows.NewLazySystemDLL("Kernel32.dll")
setConsoleMode := kernel32DLL.NewProc("SetConsoleMode")
var mode uint32
if err := syscall.GetConsoleMode(syscall.Handle(out.Fd()), &mode); err != nil {
return err
}
mode |= ENABLE_PROCESSED_OUTPUT
mode |= ENABLE_VIRTUAL_TERMINAL_PROCESSING
// If the SetConsoleMode function fails, the return value is zero.
// See https://learn.microsoft.com/en-us/windows/console/setconsolemode#return-value.
if ret, _, _ := setConsoleMode.Call(out.Fd(), uintptr(mode)); ret == 0 {
return errors.New("SetConsoleMode failed")
}
return nil
}
}
keyfile.go
+126
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@@ -0,0 +1,126 @@
// Copyright 2026 The vault Authors.
// SPDX-License-Identifier: GPL-3.0-or-later
package main
import (
"bytes"
"crypto/rand"
"encoding/binary"
"encoding/pem"
"errors"
"os"
"path/filepath"
"github.com/andydixon/vault/internal/pqcrypt"
"golang.org/x/crypto/argon2"
"golang.org/x/crypto/chacha20poly1305"
)
// A key file seals a (suite ID, master seed) pair under an Argon2id-derived
// key. The private seed never touches disk unencrypted.
const (
keyPEMType = "VAULT KEY"
argonTime = 3
argonMemory = 64 * 1024 // KiB
argonThreads = 4
slotSaltSize = 16
seedSize = 32
slotPlainSize = 2 + seedSize
slotSize = slotSaltSize + chacha20poly1305.NonceSizeX + slotPlainSize + chacha20poly1305.Overhead
)
var keyMagic = []byte("VAULTKEY1")
// keyHeader is the authenticated, non-secret prefix of every key file.
func keyHeader() []byte {
h := append([]byte(nil), keyMagic...)
h = binary.BigEndian.AppendUint32(h, argonTime)
h = binary.BigEndian.AppendUint32(h, argonMemory)
return append(h, argonThreads)
}
// sealSlot encrypts the identity's seed under passphrase.
func sealSlot(id *pqcrypt.PQIdentity, passphrase string) ([]byte, error) {
slot := make([]byte, slotSaltSize+chacha20poly1305.NonceSizeX, slotSize)
if _, err := rand.Read(slot); err != nil {
return nil, err
}
aead, err := slotAEAD(passphrase, slot[:slotSaltSize])
if err != nil {
return nil, err
}
plain := binary.BigEndian.AppendUint16(nil, id.SuiteID())
seed := id.Seed()
plain = append(plain, seed...)
clear(seed)
defer clear(plain)
return aead.Seal(slot, slot[slotSaltSize:], plain, keyHeader()), nil
}
func slotAEAD(passphrase string, salt []byte) (interface {
Seal(dst, nonce, plaintext, ad []byte) []byte
Open(dst, nonce, ciphertext, ad []byte) ([]byte, error)
}, error) {
key := argon2.IDKey([]byte(passphrase), salt, argonTime, argonMemory, argonThreads, chacha20poly1305.KeySize)
defer clear(key)
return chacha20poly1305.NewX(key)
}
// writeKeyFile creates a new key file holding a fresh identity.
func writeKeyFile(path, passphrase string) error {
id, err := pqcrypt.GeneratePQIdentity()
if err != nil {
return err
}
slot, err := sealSlot(id, passphrase)
id.Close()
if err != nil {
return err
}
body := append(keyHeader(), slot...)
if err := os.MkdirAll(filepath.Dir(path), 0o700); err != nil {
return err
}
f, err := os.OpenFile(path, os.O_WRONLY|os.O_CREATE|os.O_EXCL, 0o600)
if err != nil {
return err
}
if err := pem.Encode(f, &pem.Block{Type: keyPEMType, Bytes: body}); err != nil {
f.Close()
os.Remove(path)
return err
}
if err := f.Sync(); err != nil {
f.Close()
return err
}
return f.Close()
}
// unlockKeyFile returns the identity the passphrase unlocks.
func unlockKeyFile(path, passphrase string) (*pqcrypt.PQIdentity, error) {
data, err := os.ReadFile(path)
if err != nil {
return nil, err
}
block, rest := pem.Decode(data)
header := keyHeader()
if block == nil || block.Type != keyPEMType || len(bytes.TrimSpace(rest)) != 0 ||
len(block.Bytes) != len(header)+slotSize || !bytes.Equal(block.Bytes[:len(header)], header) {
return nil, errors.New("not a vault key file")
}
slot := block.Bytes[len(header):]
aead, err := slotAEAD(passphrase, slot[:slotSaltSize])
if err != nil {
return nil, err
}
plain, err := aead.Open(nil, slot[slotSaltSize:][:chacha20poly1305.NonceSizeX],
slot[slotSaltSize+chacha20poly1305.NonceSizeX:], header)
if err != nil {
return nil, errors.New("incorrect passphrase")
}
defer clear(plain)
return pqcrypt.NewPQIdentityFromSeed(binary.BigEndian.Uint16(plain), plain[2:])
}
main.go
+241
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@@ -0,0 +1,241 @@
// Copyright 2026 The vault Authors.
// SPDX-License-Identifier: GPL-3.0-or-later
// vault is a post-quantum encrypted file vault.
package main
import (
"flag"
"fmt"
"io"
"io/fs"
"os"
"path"
"path/filepath"
"sort"
"strings"
"github.com/andydixon/vault/internal/term"
)
const usage = `Usage:
vault genkey create a new passphrase-protected key
vault init create a new, empty vault
vault add FILE|DIR [FOLDER] encrypt a file or directory into the vault,
optionally under a folder inside the vault
vault list [PREFIX] list stored files
vault get NAME [-o OUTPUT] decrypt a stored file (default: its base name)
vault mv OLD NEW rename a stored file
vault rm NAME delete a stored file
Options (any command):
--key PATH key file (default $VAULT_KEY, else ~/.vault/key)
--vault DIR vault directory (default $VAULT_DIR, else ~/.vault/store)
The passphrase is read from the terminal, or from $VAULT_PASSPHRASE.`
const passphraseEnv = "VAULT_PASSPHRASE"
func main() {
if len(os.Args) < 2 {
fmt.Fprintln(os.Stderr, usage)
os.Exit(2)
}
cmd, args := os.Args[1], os.Args[2:]
fset := flag.NewFlagSet("vault "+cmd, flag.ContinueOnError)
fset.SetOutput(io.Discard)
keyPath := fset.String("key", defaultPath("VAULT_KEY", "key"), "")
vaultDir := fset.String("vault", defaultPath("VAULT_DIR", "store"), "")
output := fset.String("o", "", "")
pos, err := parseInterleaved(fset, args)
if err != nil {
fail("%v\n\n%s", err, usage)
}
want := func(min, max int) {
if len(pos) < min || len(pos) > max {
fail("wrong number of arguments for %s\n\n%s", cmd, usage)
}
}
switch cmd {
case "genkey":
want(0, 0)
if _, err := os.Stat(*keyPath); err == nil {
fail("%s already exists", *keyPath)
}
pass := newPassphrase("passphrase")
check(writeKeyFile(*keyPath, pass))
fmt.Fprintf(os.Stderr, "key written to %s\n", *keyPath)
case "init":
want(0, 0)
check(initStore(*vaultDir))
fmt.Fprintf(os.Stderr, "vault created at %s\n", *vaultDir)
case "add":
want(1, 2)
dest := ""
if len(pos) == 2 {
dest = strings.Trim(pos[1], "/")
}
s := open(*keyPath, *vaultDir)
cat, err := s.catalogue()
check(err)
check(addPath(s, cat, pos[0], dest))
case "list", "ls":
want(0, 1)
prefix := ""
if len(pos) == 1 {
prefix = strings.Trim(pos[0], "/")
}
cat, err := open(*keyPath, *vaultDir).catalogue()
check(err)
list(cat, prefix)
case "get":
want(1, 1)
out := *output
if out == "" {
out = path.Base(pos[0])
}
check(open(*keyPath, *vaultDir).get(pos[0], out))
case "mv", "rename":
want(2, 2)
check(open(*keyPath, *vaultDir).rename(pos[0], pos[1]))
case "rm", "delete":
want(1, 1)
check(open(*keyPath, *vaultDir).delete(pos[0]))
case "help", "-h", "--help":
fmt.Println(usage)
default:
fail("unknown command %q\n\n%s", cmd, usage)
}
}
// parseInterleaved lets flags appear before, between or after positional
// arguments.
func parseInterleaved(fset *flag.FlagSet, args []string) ([]string, error) {
var pos []string
for {
if err := fset.Parse(args); err != nil {
return nil, err
}
if fset.NArg() == 0 {
return pos, nil
}
pos = append(pos, fset.Arg(0))
args = fset.Args()[1:]
}
}
func defaultPath(env, name string) string {
if v := os.Getenv(env); v != "" {
return v
}
home, err := os.UserHomeDir()
if err != nil {
fail("cannot find home directory; set %s", env)
}
return filepath.Join(home, ".vault", name)
}
func open(keyPath, vaultDir string) *store {
pass, err := term.ReadPassphrase("Enter passphrase:", passphraseEnv)
check(err)
id, err := unlockKeyFile(keyPath, pass)
check(err)
s, err := openStore(vaultDir, id)
check(err)
return s
}
func newPassphrase(what string) string {
if p, ok := os.LookupEnv(passphraseEnv); ok && p != "" {
return p
}
p, err := term.ReadPassphrase("Enter "+what+":", passphraseEnv)
check(err)
if p == "" {
fail("%s must not be empty", what)
}
again, err := term.ReadPassphrase("Confirm "+what+":", passphraseEnv)
check(err)
if p != again {
fail("%ss do not match", what)
}
return p
}
// addPath adds a file, or every regular file under a directory, beneath dest.
func addPath(s *store, cat map[string][]*record, src, dest string) error {
info, err := os.Stat(src)
if err != nil {
return err
}
base := filepath.Base(filepath.Clean(src))
if !info.IsDir() {
return addOne(s, cat, src, path.Join(dest, base))
}
return filepath.WalkDir(src, func(p string, d fs.DirEntry, err error) error {
if err != nil || d.IsDir() {
return err
}
if !d.Type().IsRegular() {
fmt.Fprintf(os.Stderr, "skipping %s: not a regular file\n", p)
return nil
}
rel, err := filepath.Rel(src, p)
if err != nil {
return err
}
return addOne(s, cat, p, path.Join(dest, base, filepath.ToSlash(rel)))
})
}
func addOne(s *store, cat map[string][]*record, src, name string) error {
replaced, err := s.add(cat, src, name)
if err != nil {
return err
}
verb := "added"
if replaced {
verb = "replaced"
}
fmt.Fprintf(os.Stderr, "%s %s\n", verb, name)
return nil
}
func list(cat map[string][]*record, prefix string) {
var names []string
for name := range cat {
if prefix == "" || name == prefix || strings.HasPrefix(name, prefix+"/") {
names = append(names, name)
}
}
sort.Strings(names)
for _, name := range names {
r := cat[name][0]
fmt.Printf("%10s %s %s\n", humanSize(r.Size), r.Modified.Local().Format("2006-01-02 15:04"), name)
}
}
func humanSize(n int64) string {
const unit = 1024
if n < unit {
return fmt.Sprintf("%d B", n)
}
div, exp := int64(unit), 0
for m := n / unit; m >= unit; m /= unit {
div *= unit
exp++
}
return fmt.Sprintf("%.1f %ciB", float64(n)/float64(div), "KMGTPE"[exp])
}
func check(err error) {
if err != nil {
fail("%v", err)
}
}
func fail(format string, args ...any) {
fmt.Fprintf(os.Stderr, "vault: "+format+"\n", args...)
os.Exit(1)
}
store.go
+426
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@@ -0,0 +1,426 @@
// Copyright 2026 The vault Authors.
// SPDX-License-Identifier: GPL-3.0-or-later
package main
import (
"bytes"
"crypto/rand"
"encoding/binary"
"encoding/hex"
"encoding/json"
"errors"
"fmt"
"io"
"os"
"path"
"path/filepath"
"sort"
"strings"
"time"
"unicode"
"unicode/utf8"
"github.com/andydixon/vault/internal/pqcrypt"
)
// On disk a vault is:
//
// DIR/.vault marker
// DIR/records/<id> one encrypted catalogue record per file
// DIR/objects/<id> one encrypted file body per record
//
// IDs are random. Records are padded to one fixed size and objects to
// power-of-two buckets, so the storage reveals neither names, exact sizes nor
// timestamps. Every ciphertext's mtime is pinned to the epoch.
const (
markerName = ".vault"
markerContent = "VAULT 1\n"
recordsDir = "records"
objectsDir = "objects"
recordSize = 4096
nameLimit = 1024
fileLimit = int64(1) << 40
minPadding = int64(64 << 10)
idSize = 16
)
type record struct {
Name string `json:"name"`
Object string `json:"object"`
Size int64 `json:"size"`
Mode uint32 `json:"mode"`
Modified time.Time `json:"modified"`
Added time.Time `json:"added"`
id string // record file ID; not stored
}
type store struct {
root string
id *pqcrypt.PQIdentity
}
func initStore(root string) error {
if _, err := os.Stat(filepath.Join(root, markerName)); err == nil {
return fmt.Errorf("%s is already a vault", root)
}
for _, dir := range []string{root, filepath.Join(root, recordsDir), filepath.Join(root, objectsDir)} {
if err := os.MkdirAll(dir, 0o700); err != nil {
return err
}
}
return os.WriteFile(filepath.Join(root, markerName), []byte(markerContent), 0o600)
}
func openStore(root string, id *pqcrypt.PQIdentity) (*store, error) {
marker, err := os.ReadFile(filepath.Join(root, markerName))
if err != nil || string(marker) != markerContent {
return nil, fmt.Errorf("%s is not a vault; run vault init", root)
}
return &store{root: root, id: id}, nil
}
func randomID() (string, error) {
b := make([]byte, idSize)
if _, err := rand.Read(b); err != nil {
return "", err
}
return hex.EncodeToString(b), nil
}
func validID(s string) bool {
b, err := hex.DecodeString(s)
return err == nil && len(b) == idSize && hex.EncodeToString(b) == s
}
func validName(name string) bool {
if name == "" || len(name) > nameLimit || !utf8.ValidString(name) || path.Clean(name) != name ||
path.IsAbs(name) || name == "." || name == ".." || strings.HasPrefix(name, "../") || strings.Contains(name, "\\") {
return false
}
for _, r := range name {
if unicode.IsControl(r) {
return false
}
}
return true
}
// paddedSize rounds size up to the next power-of-two bucket.
func paddedSize(size int64) int64 {
p := minPadding
for p < size {
p *= 2
}
return p
}
// writeCiphertext encrypts to dir/id via a temporary file, so a partial
// ciphertext never appears under a real ID.
func (s *store) writeCiphertext(dir, id string, write func(io.Writer) error) error {
dir = filepath.Join(s.root, dir)
tmp, err := os.CreateTemp(dir, ".pending-")
if err != nil {
return err
}
defer os.Remove(tmp.Name())
defer tmp.Close()
w, err := pqcrypt.Encrypt(tmp, s.id.Recipient())
if err != nil {
return err
}
if err := write(w); err != nil {
return err
}
if err := w.Close(); err != nil {
return err
}
if err := tmp.Sync(); err != nil {
return err
}
if err := tmp.Close(); err != nil {
return err
}
epoch := time.Unix(0, 0)
if err := os.Chtimes(tmp.Name(), epoch, epoch); err != nil {
return err
}
if err := os.Rename(tmp.Name(), filepath.Join(dir, id)); err != nil {
return err
}
return syncDir(dir)
}
func syncDir(dir string) error {
d, err := os.Open(dir)
if err != nil {
return err
}
defer d.Close()
return d.Sync()
}
func (s *store) writeRecord(r *record) error {
data, err := json.Marshal(r)
if err != nil {
return err
}
if len(data) > recordSize-4 {
return errors.New("catalogue record too large")
}
plain := make([]byte, recordSize)
binary.BigEndian.PutUint32(plain, uint32(len(data)))
copy(plain[4:], data)
if _, err := rand.Read(plain[4+len(data):]); err != nil {
return err
}
if r.id, err = randomID(); err != nil {
return err
}
return s.writeCiphertext(recordsDir, r.id, func(w io.Writer) error {
_, err := w.Write(plain)
return err
})
}
// catalogue decrypts every record this identity can open. Records sealed to
// a different key are skipped silently: they are simply not ours.
func (s *store) catalogue() (map[string][]*record, error) {
entries, err := os.ReadDir(filepath.Join(s.root, recordsDir))
if err != nil {
return nil, err
}
byName := map[string][]*record{}
for _, e := range entries {
if !validID(e.Name()) {
continue
}
r, err := s.readRecord(e.Name())
var noMatch *pqcrypt.NoIdentityMatchError
if errors.As(err, &noMatch) {
continue
}
if err != nil {
fmt.Fprintf(os.Stderr, "vault: skipping unreadable record %s: %v\n", e.Name(), err)
continue
}
byName[r.Name] = append(byName[r.Name], r)
}
// Newest first, so [0] is current. Duplicates only exist after an
// interrupted replace; the next write of that name cleans them up.
for _, rs := range byName {
sort.Slice(rs, func(i, j int) bool { return rs[i].Added.After(rs[j].Added) })
}
return byName, nil
}
func (s *store) readRecord(id string) (*record, error) {
f, err := os.Open(filepath.Join(s.root, recordsDir, id))
if err != nil {
return nil, err
}
defer f.Close()
pr, err := pqcrypt.Decrypt(f, s.id)
if err != nil {
return nil, err
}
plain, err := io.ReadAll(io.LimitReader(pr, recordSize+1))
if err != nil {
return nil, err
}
if len(plain) != recordSize {
return nil, errors.New("wrong record size")
}
n := binary.BigEndian.Uint32(plain)
if n > recordSize-4 {
return nil, errors.New("malformed record")
}
r := &record{id: id}
dec := json.NewDecoder(bytes.NewReader(plain[4 : 4+n]))
dec.DisallowUnknownFields()
if err := dec.Decode(r); err != nil {
return nil, err
}
if !validName(r.Name) || !validID(r.Object) || r.Size < 0 || r.Size > fileLimit {
return nil, errors.New("malformed record")
}
return r, nil
}
// add stores the file at src as name, replacing any existing file of that
// name, and updates cat to match. It reports whether something was replaced.
func (s *store) add(cat map[string][]*record, src, name string) (bool, error) {
if !validName(name) {
return false, fmt.Errorf("invalid vault path %q", name)
}
f, err := os.Open(src)
if err != nil {
return false, err
}
defer f.Close()
info, err := f.Stat()
if err != nil {
return false, err
}
if !info.Mode().IsRegular() || info.Size() > fileLimit {
return false, fmt.Errorf("%s: not a regular file of at most 1 TiB", src)
}
objID, err := randomID()
if err != nil {
return false, err
}
err = s.writeCiphertext(objectsDir, objID, func(w io.Writer) error {
// The object ID leads the plaintext so a record can only ever
// open the object it names, not one swapped in under its ID.
raw, _ := hex.DecodeString(objID)
if _, err := w.Write(raw); err != nil {
return err
}
n, err := io.Copy(w, io.LimitReader(f, info.Size()))
if err != nil {
return err
}
if n != info.Size() {
return fmt.Errorf("%s changed while being added", src)
}
_, err = io.CopyN(w, rand.Reader, paddedSize(idSize+n)-idSize-n)
return err
})
if err != nil {
return false, err
}
r := &record{
Name: name, Object: objID, Size: info.Size(), Mode: uint32(info.Mode().Perm()),
Modified: info.ModTime().UTC(), Added: time.Now().UTC(),
}
if err := s.writeRecord(r); err != nil {
os.Remove(filepath.Join(s.root, objectsDir, objID))
return false, err
}
replaced := len(cat[name]) > 0
if err := s.remove(cat, name, true); err != nil {
return replaced, err
}
cat[name] = []*record{r}
return replaced, nil
}
// remove deletes every record for name and, when dropObjects is set, any of
// their objects no other record still uses. Records go first, so an
// interruption only ever leaves an orphaned object.
func (s *store) remove(cat map[string][]*record, name string, dropObjects bool) error {
inUse := map[string]bool{}
for n, rs := range cat {
for _, r := range rs {
if n != name {
inUse[r.Object] = true
}
}
}
for _, r := range cat[name] {
if err := os.Remove(filepath.Join(s.root, recordsDir, r.id)); err != nil {
return err
}
if dropObjects && !inUse[r.Object] {
if err := os.Remove(filepath.Join(s.root, objectsDir, r.Object)); err != nil && !os.IsNotExist(err) {
return err
}
}
}
return nil
}
func (s *store) lookup(name string) (map[string][]*record, *record, error) {
cat, err := s.catalogue()
if err != nil {
return nil, nil, err
}
rs := cat[name]
if len(rs) == 0 {
return nil, nil, fmt.Errorf("%s: not in the vault", name)
}
return cat, rs[0], nil
}
func (s *store) delete(name string) error {
cat, _, err := s.lookup(name)
if err != nil {
return err
}
return s.remove(cat, name, true)
}
func (s *store) rename(oldName, newName string) error {
if !validName(newName) {
return fmt.Errorf("invalid vault path %q", newName)
}
cat, r, err := s.lookup(oldName)
if err != nil {
return err
}
if len(cat[newName]) > 0 {
return fmt.Errorf("%s already exists", newName)
}
moved := *r
moved.Name = newName
if err := s.writeRecord(&moved); err != nil {
return err
}
return s.remove(cat, oldName, false)
}
// get decrypts name to out. Nothing appears at out until the entire object,
// padding included, has authenticated.
func (s *store) get(name, out string) error {
_, r, err := s.lookup(name)
if err != nil {
return err
}
if _, err := os.Lstat(out); err == nil {
return fmt.Errorf("%s already exists", out)
}
f, err := os.Open(filepath.Join(s.root, objectsDir, r.Object))
if err != nil {
return err
}
defer f.Close()
pr, err := pqcrypt.Decrypt(f, s.id)
if err != nil {
return err
}
head := make([]byte, idSize)
if _, err := io.ReadFull(pr, head); err != nil || hex.EncodeToString(head) != r.Object {
return errors.New("object does not match its catalogue record")
}
tmp, err := os.CreateTemp(filepath.Dir(out), ".vault-get-")
if err != nil {
return err
}
defer os.Remove(tmp.Name())
defer tmp.Close()
if _, err := io.CopyN(tmp, pr, r.Size); err != nil {
return err
}
pad, err := io.Copy(io.Discard, pr)
if err != nil {
return err
}
if idSize+r.Size+pad != paddedSize(idSize+r.Size) {
return errors.New("object size does not match its catalogue record")
}
if err := tmp.Chmod(os.FileMode(r.Mode) & 0o777); err != nil {
return err
}
if err := tmp.Close(); err != nil {
return err
}
if err := os.Chtimes(tmp.Name(), r.Modified, r.Modified); err != nil {
return err
}
if _, err := os.Lstat(out); err == nil {
return fmt.Errorf("%s already exists", out)
}
return os.Rename(tmp.Name(), out)
}
vault_test.go
+96
View File
@@ -0,0 +1,96 @@
// Copyright 2026 The vault Authors.
// SPDX-License-Identifier: GPL-3.0-or-later
package main
import (
"bytes"
"os"
"path/filepath"
"testing"
)
func TestKeyFile(t *testing.T) {
path := filepath.Join(t.TempDir(), "key")
if err := writeKeyFile(path, "pass"); err != nil {
t.Fatal(err)
}
if _, err := unlockKeyFile(path, "wrong"); err == nil {
t.Fatal("wrong passphrase unlocked the key")
}
if _, err := unlockKeyFile(path, "pass"); err != nil {
t.Fatal(err)
}
}
func newTestStore(t *testing.T, keyPath, pass string) *store {
t.Helper()
id, err := unlockKeyFile(keyPath, pass)
if err != nil {
t.Fatal(err)
}
s, err := openStore(filepath.Join(filepath.Dir(keyPath), "store"), id)
if err != nil {
t.Fatal(err)
}
return s
}
func TestStoreLifecycle(t *testing.T) {
dir := t.TempDir()
keyPath := filepath.Join(dir, "key")
if err := writeKeyFile(keyPath, "pass"); err != nil {
t.Fatal(err)
}
if err := initStore(filepath.Join(dir, "store")); err != nil {
t.Fatal(err)
}
s := newTestStore(t, keyPath, "pass")
src := filepath.Join(dir, "in")
want := bytes.Repeat([]byte("x"), 70000)
os.WriteFile(src, want, 0o640)
cat, _ := s.catalogue()
if _, err := s.add(cat, src, "a/b"); err != nil {
t.Fatal(err)
}
if replaced, err := s.add(cat, src, "a/b"); err != nil || !replaced {
t.Fatalf("replace: %v %v", replaced, err)
}
if _, err := s.add(cat, src, "c"); err != nil {
t.Fatal(err)
}
if cat, _ = s.catalogue(); len(cat) != 2 || len(cat["a/b"]) != 1 {
t.Fatalf("catalogue = %v", cat)
}
if err := s.rename("a/b", "d"); err != nil {
t.Fatal(err)
}
out := filepath.Join(dir, "out")
if err := s.get("d", out); err != nil {
t.Fatal(err)
}
if got, _ := os.ReadFile(out); !bytes.Equal(got, want) {
t.Fatal("round trip mismatch")
}
if err := s.get("d", out); err == nil {
t.Fatal("get overwrote an existing file")
}
// Swapping one object for another must be detected.
cat, _ = s.catalogue()
d, c := cat["d"][0], cat["c"][0]
objects := filepath.Join(s.root, objectsDir)
data, _ := os.ReadFile(filepath.Join(objects, c.Object))
os.WriteFile(filepath.Join(objects, d.Object), data, 0o600)
if err := s.get("d", filepath.Join(dir, "swapped")); err == nil {
t.Fatal("swapped object was accepted")
}
if err := s.delete("c"); err != nil {
t.Fatal(err)
}
if cat, _ = s.catalogue(); len(cat) != 1 {
t.Fatalf("after delete: %v", cat)
}
}