diff options
| -rw-r--r-- | oae2.go | 27 | ||||
| -rw-r--r-- | oae2_test.go | 99 |
2 files changed, 113 insertions, 13 deletions
@@ -33,6 +33,11 @@ import ( "math" ) +// ErrInvalid is returned from methods on Reader when the stream failed to +// authenticate. This can indicate that a wrong key was used, or that the data +// was tampered with. +var ErrInvalid = errors.New("invalid stream") + const ( nonceSize = 12 aeadOverhead = 16 @@ -107,7 +112,11 @@ func (e *segmentEncrypter) decryptSegment(segment []byte, lastSegment bool) ([]b if err != nil { return nil, err } - return e.aead.Open(segment[:0], nonce, segment, ad) + plainText, err := e.aead.Open(segment[:0], nonce, segment, ad) + if err != nil { + return nil, fmt.Errorf("%w: %s", ErrInvalid, err) + } + return plainText, nil } // A Writer wraps an io.Writer and encrypts the data in segments. Make sure to @@ -296,8 +305,8 @@ func (r *Reader) initialize() error { r.initialized = true buf := make([]byte, saltSize) if _, r.err = io.ReadFull(&r.r, buf); r.err != nil { - if r.err == io.EOF { - r.err = io.ErrUnexpectedEOF + if r.err == io.EOF || r.err == io.ErrUnexpectedEOF { + r.err = fmt.Errorf("%w: too short", ErrInvalid) } return r.err } @@ -308,7 +317,7 @@ func (r *Reader) initialize() error { // additional data if err := r.fillBuf(); err != nil { if err == io.EOF { - r.err = io.ErrUnexpectedEOF + r.err = fmt.Errorf("%w: too short", ErrInvalid) return r.err } return err @@ -349,7 +358,8 @@ func (r *Reader) fillBuf() error { return nil } -// Read implements io.Reader. +// Read implements io.Reader. Read returns an error wrapping [ErrInvalid] if +// the stream fails authentication. func (r *Reader) Read(buf []byte) (int, error) { if err := r.init(); err != nil { return 0, err @@ -367,7 +377,8 @@ func (r *Reader) Read(buf []byte) (int, error) { return n, nil } -// WriteTo implements io.WriterTo. +// WriteTo implements io.WriterTo. WriteTo returns an error wrapping +// [ErrInvalid] if the stream fails authentication. func (r *Reader) WriteTo(w io.Writer) (int64, error) { if err := r.init(); err != nil { return 0, err @@ -427,7 +438,9 @@ func (r *Reader) seek(offset int64) (int64, error) { } // Seek implements io.Seeker. If the underlying reader does not implement -// io.Seeker, Seek returns [errors.ErrUnsupported]. +// io.Seeker, Seek returns an error wrapping [errors.ErrUnsupported]. Seek may +// also return an error wrapping [ErrInvalid] if the seeked-to segment +// fails authentication. func (r *Reader) Seek(offset int64, whence int) (int64, error) { if _, ok := r.r.r.(io.Seeker); !ok { return 0, fmt.Errorf("%w", errors.ErrUnsupported) diff --git a/oae2_test.go b/oae2_test.go index f0ed37f..5ca26e6 100644 --- a/oae2_test.go +++ b/oae2_test.go @@ -3,6 +3,7 @@ package oae2 import ( "bytes" "crypto/rand" + "errors" "io" "strings" "testing" @@ -66,8 +67,94 @@ func TestInvalid(t *testing.T) { key = "asdf" ) _, err := io.ReadAll(NewReader(strings.NewReader(msg), []byte(key), 1, nil)) - if err == nil { - t.Errorf("Message %q passed validation, want error", msg) + if !errors.Is(err, ErrInvalid) { + t.Errorf("Reader.Read: decrypt message %q returned error %v, want ErrInvalid", msg, err) + } +} + +func TestWrongKeyRead(t *testing.T) { + t.Parallel() + + const ( + key = "asdf" + additionalData = "additional data" + ) + + encryptedBuf := new(bytes.Buffer) + if _, err := NewWriter(encryptedBuf, []byte(key), 4*1024*1024, []byte(additionalData)).Write([]byte("hello world")); err != nil { + t.Fatalf("Failed to encrypt test data: %s", err) + } + + for _, tc := range []struct { + desc string + key string + additionalData string + }{{ + desc: "WrongKey", + key: "wrong key", + }, { + desc: "WrongData", + additionalData: "wrong additional data", + }} { + t.Run(tc.desc, func(t *testing.T) { + t.Parallel() + + k := tc.key + if k == "" { + k = key + } + ad := tc.additionalData + if ad == "" { + ad = additionalData + } + _, err := io.ReadAll(NewReader(bytes.NewReader(encryptedBuf.Bytes()), []byte(key), 1, nil)) + if !errors.Is(err, ErrInvalid) { + t.Errorf("Reader.Read: message returned error %v with key %q and data %q, want ErrInvalid", err, k, ad) + } + }) + } +} + +func TestWrongKeyWriteTo(t *testing.T) { + t.Parallel() + + const ( + key = "asdf" + additionalData = "additional data" + ) + + encryptedBuf := new(bytes.Buffer) + if _, err := NewWriter(encryptedBuf, []byte(key), 4*1024*1024, []byte(additionalData)).Write([]byte("hello world")); err != nil { + t.Fatalf("Failed to encrypt test data: %s", err) + } + + for _, tc := range []struct { + desc string + key string + additionalData string + }{{ + desc: "WrongKey", + key: "wrong key", + }, { + desc: "WrongData", + additionalData: "wrong additional data", + }} { + t.Run(tc.desc, func(t *testing.T) { + t.Parallel() + + k := tc.key + if k == "" { + k = key + } + ad := tc.additionalData + if ad == "" { + ad = additionalData + } + _, err := NewReader(bytes.NewReader(encryptedBuf.Bytes()), []byte(key), 1, nil).WriteTo(io.Discard) + if !errors.Is(err, ErrInvalid) { + t.Errorf("Reader.WriteTo: message returned error %v with key %q and data %q, want ErrInvalid", err, k, ad) + } + }) } } @@ -220,8 +307,8 @@ func FuzzReadInvalid(f *testing.F) { password := make([]byte, 32) // Get a random password so that we can be sure msg is invalid rand.Read(password) - if _, err := io.ReadAll(NewReader(strings.NewReader(msg), password, segmentSize, []byte(additionalData))); err == nil { - t.Errorf("Reader.Read: message passed validation") + if _, err := io.ReadAll(NewReader(strings.NewReader(msg), password, segmentSize, []byte(additionalData))); !errors.Is(err, ErrInvalid) { + t.Errorf("Reader.Read: invalid message got error %v, want ErrInvalid", err) } }) } @@ -235,8 +322,8 @@ func FuzzWriteToInvalid(f *testing.F) { } password := make([]byte, 32) rand.Read(password) - if _, err := NewReader(strings.NewReader(msg), password, segmentSize, []byte(additionalData)).WriteTo(io.Discard); err == nil { - t.Errorf("Reader.WriteTo: message passed validation") + if _, err := NewReader(strings.NewReader(msg), password, segmentSize, []byte(additionalData)).WriteTo(io.Discard); !errors.Is(err, ErrInvalid) { + t.Errorf("Reader.WriteTo: invalid message got error %v, want ErrInvalid", err) } }) } |