feat(packet): expose v2 parsed fields in the SymmetricallyEncrypted s…

…truct (#183) The SymmetricallyEncrypted (SEIPD) packet type did not expose the parsed fields for SEIPDv2. Thus, it prevents external users of the packet parser to inspect parsed values. This commit addressed this issue by making them public.
ProtonMail · Aug 28, 2023 · 3c4c8a2 · 3c4c8a2
1 parent 5aa5874
commit 3c4c8a2
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Showing 3 changed files with 34 additions and 33 deletions.
diff --git a/openpgp/packet/symmetrically_encrypted.go b/openpgp/packet/symmetrically_encrypted.go
@@ -24,10 +24,10 @@ type SymmetricallyEncrypted struct {
 	prefix []byte
 
 	// Specific to version 2
-	cipher        CipherFunction
-	mode          AEADMode
-	chunkSizeByte byte
-	salt          [aeadSaltSize]byte
+	Cipher        CipherFunction
+	Mode          AEADMode
+	ChunkSizeByte byte
+	Salt          [aeadSaltSize]byte
 }
 
 const (

diff --git a/openpgp/packet/symmetrically_encrypted_aead.go b/openpgp/packet/symmetrically_encrypted_aead.go
@@ -7,9 +7,10 @@ package packet
 import (
 	"crypto/cipher"
 	"crypto/sha256"
+	"io"
+
 	"github.com/ProtonMail/go-crypto/openpgp/errors"
 	"golang.org/x/crypto/hkdf"
-	"io"
 )
 
 // parseAead parses a V2 SEIPD packet (AEAD) as specified in
@@ -21,26 +22,26 @@ func (se *SymmetricallyEncrypted) parseAead(r io.Reader) error {
 	}
 
 	// Cipher
-	se.cipher = CipherFunction(headerData[0])
+	se.Cipher = CipherFunction(headerData[0])
 	// cipherFunc must have block size 16 to use AEAD
-	if se.cipher.blockSize() != 16 {
-		return errors.UnsupportedError("invalid aead cipher: " + string(se.cipher))
+	if se.Cipher.blockSize() != 16 {
+		return errors.UnsupportedError("invalid aead cipher: " + string(se.Cipher))
 	}
 
 	// Mode
-	se.mode = AEADMode(headerData[1])
-	if se.mode.TagLength() == 0 {
-		return errors.UnsupportedError("unknown aead mode: " + string(se.mode))
+	se.Mode = AEADMode(headerData[1])
+	if se.Mode.TagLength() == 0 {
+		return errors.UnsupportedError("unknown aead mode: " + string(se.Mode))
 	}
 
 	// Chunk size
-	se.chunkSizeByte = headerData[2]
-	if se.chunkSizeByte > 16 {
-		return errors.UnsupportedError("invalid aead chunk size byte: " + string(se.chunkSizeByte))
+	se.ChunkSizeByte = headerData[2]
+	if se.ChunkSizeByte > 16 {
+		return errors.UnsupportedError("invalid aead chunk size byte: " + string(se.ChunkSizeByte))
 	}
 
 	// Salt
-	if n, err := io.ReadFull(r, se.salt[:]); n < aeadSaltSize {
+	if n, err := io.ReadFull(r, se.Salt[:]); n < aeadSaltSize {
 		return errors.StructuralError("could not read aead salt: " + err.Error())
 	}
 
@@ -52,19 +53,19 @@ func (se *SymmetricallyEncrypted) associatedData() []byte {
 	return []byte{
 		0xD2,
 		symmetricallyEncryptedVersionAead,
-		byte(se.cipher),
-		byte(se.mode),
-		se.chunkSizeByte,
+		byte(se.Cipher),
+		byte(se.Mode),
+		se.ChunkSizeByte,
 	}
 }
 
 // decryptAead decrypts a V2 SEIPD packet (AEAD) as specified in
 // https://www.ietf.org/archive/id/draft-ietf-openpgp-crypto-refresh-07.html#section-5.13.2
 func (se *SymmetricallyEncrypted) decryptAead(inputKey []byte) (io.ReadCloser, error) {
-	aead, nonce := getSymmetricallyEncryptedAeadInstance(se.cipher, se.mode, inputKey, se.salt[:], se.associatedData())
+	aead, nonce := getSymmetricallyEncryptedAeadInstance(se.Cipher, se.Mode, inputKey, se.Salt[:], se.associatedData())
 
 	// Carry the first tagLen bytes
-	tagLen := se.mode.TagLength()
+	tagLen := se.Mode.TagLength()
 	peekedBytes := make([]byte, tagLen)
 	n, err := io.ReadFull(se.Contents, peekedBytes)
 	if n < tagLen || (err != nil && err != io.EOF) {
@@ -74,7 +75,7 @@ func (se *SymmetricallyEncrypted) decryptAead(inputKey []byte) (io.ReadCloser, e
 	return &aeadDecrypter{
 		aeadCrypter: aeadCrypter{
 			aead:           aead,
-			chunkSize:      decodeAEADChunkSize(se.chunkSizeByte),
+			chunkSize:      decodeAEADChunkSize(se.ChunkSizeByte),
 			initialNonce:   nonce,
 			associatedData: se.associatedData(),
 			chunkIndex:     make([]byte, 8),

diff --git a/openpgp/packet/symmetrically_encrypted_test.go b/openpgp/packet/symmetrically_encrypted_test.go
@@ -175,20 +175,20 @@ func TestAeadRfcVector(t *testing.T) {
 		t.Errorf("found wrong version, want: %d, got: %d", symmetricallyEncryptedVersionAead, se.Version)
 	}
 
-	if se.cipher != CipherAES128 {
-		t.Errorf("found wrong cipher, want: %d, got: %d", CipherAES128, se.cipher)
+	if se.Cipher != CipherAES128 {
+		t.Errorf("found wrong cipher, want: %d, got: %d", CipherAES128, se.Cipher)
 	}
 
-	if se.mode != AEADModeGCM {
-		t.Errorf("found wrong mode, want: %d, got: %d", AEADModeGCM, se.mode)
+	if se.Mode != AEADModeGCM {
+		t.Errorf("found wrong mode, want: %d, got: %d", AEADModeGCM, se.Mode)
 	}
 
-	if !bytes.Equal(se.salt[:], expectedSalt) {
-		t.Errorf("found wrong salt, want: %x, got: %x", expectedSalt, se.salt)
+	if !bytes.Equal(se.Salt[:], expectedSalt) {
+		t.Errorf("found wrong salt, want: %x, got: %x", expectedSalt, se.Salt)
 	}
 
-	if se.chunkSizeByte != 0x06 {
-		t.Errorf("found wrong chunk size byte, want: %d, got: %d", 0x06, se.chunkSizeByte)
+	if se.ChunkSizeByte != 0x06 {
+		t.Errorf("found wrong chunk size byte, want: %d, got: %d", 0x06, se.ChunkSizeByte)
 	}
 
 	aeadReader, err := se.Decrypt(CipherFunction(0), key)
@@ -270,12 +270,12 @@ func testSerializeAead(t *testing.T, cipherSuite CipherSuite) {
 		t.Errorf("found wrong version, want: %d, got: %d", symmetricallyEncryptedVersionAead, se.Version)
 	}
 
-	if se.cipher != cipherSuite.Cipher {
-		t.Errorf("found wrong cipher, want: %d, got: %d", cipherSuite.Cipher, se.cipher)
+	if se.Cipher != cipherSuite.Cipher {
+		t.Errorf("found wrong cipher, want: %d, got: %d", cipherSuite.Cipher, se.Cipher)
 	}
 
-	if se.mode != cipherSuite.Mode {
-		t.Errorf("found wrong mode, want: %d, got: %d", cipherSuite.Mode, se.mode)
+	if se.Mode != cipherSuite.Mode {
+		t.Errorf("found wrong mode, want: %d, got: %d", cipherSuite.Mode, se.Mode)
 	}
 
 	r, err := se.Decrypt(CipherFunction(0), key)