some tweaks to 17, 44 and 59.

This commit is contained in:
fiatjaf
2024-09-14 22:47:26 -03:00
parent 0656357a60
commit 46a0c95b96
3 changed files with 31 additions and 38 deletions

View File

@@ -81,7 +81,7 @@ func ListenForMessages(
func(otherpubkey, ciphertext string) (string, error) { return kr.Decrypt(ctx, ciphertext, otherpubkey) }, func(otherpubkey, ciphertext string) (string, error) { return kr.Decrypt(ctx, ciphertext, otherpubkey) },
) )
if err != nil { if err != nil {
nostr.InfoLogger.Printf("[nip17] failed to unwrap received message: %s\n", err) nostr.InfoLogger.Printf("[nip17] failed to unwrap received message '%s' from %s: %s\n", ie.Event, ie.Relay.URL, err)
continue continue
} }

View File

@@ -8,7 +8,6 @@ import (
"encoding/base64" "encoding/base64"
"encoding/binary" "encoding/binary"
"encoding/hex" "encoding/hex"
"errors"
"fmt" "fmt"
"io" "io"
"math" "math"
@@ -26,20 +25,19 @@ const (
MaxPlaintextSize = 0xffff // 65535 (64kb-1) => padded to 64kb MaxPlaintextSize = 0xffff // 65535 (64kb-1) => padded to 64kb
) )
var zeroes = [32]byte{}
type encryptOptions struct { type encryptOptions struct {
err error err error
nonce []byte nonce [32]byte
} }
// Deprecated: use WithCustomNonce instead of WithCustomSalt, so the naming is less confusing func WithCustomNonce(nonce []byte) func(opts *encryptOptions) {
var WithCustomSalt = WithCustomNonce
func WithCustomNonce(salt []byte) func(opts *encryptOptions) {
return func(opts *encryptOptions) { return func(opts *encryptOptions) {
if len(salt) != 32 { if len(nonce) != 32 {
opts.err = errors.New("salt must be 32 bytes") opts.err = fmt.Errorf("invalid custom nonce, must be 32 bytes, got %d", len(nonce))
} }
opts.nonce = salt copy(opts.nonce[:], nonce)
} }
} }
@@ -54,9 +52,8 @@ func Encrypt(plaintext string, conversationKey [32]byte, applyOptions ...func(op
} }
nonce := opts.nonce nonce := opts.nonce
if nonce == nil { if nonce == zeroes {
nonce := make([]byte, 32) if _, err := rand.Read(nonce[:]); err != nil {
if _, err := rand.Read(nonce); err != nil {
return "", err return "", err
} }
} }
@@ -69,7 +66,7 @@ func Encrypt(plaintext string, conversationKey [32]byte, applyOptions ...func(op
plain := []byte(plaintext) plain := []byte(plaintext)
size := len(plain) size := len(plain)
if size < MinPlaintextSize || size > MaxPlaintextSize { if size < MinPlaintextSize || size > MaxPlaintextSize {
return "", errors.New("plaintext should be between 1b and 64kB") return "", fmt.Errorf("plaintext should be between 1b and 64kB")
} }
padding := calcPadding(size) padding := calcPadding(size)
@@ -89,7 +86,7 @@ func Encrypt(plaintext string, conversationKey [32]byte, applyOptions ...func(op
concat := make([]byte, 1+32+len(ciphertext)+32) concat := make([]byte, 1+32+len(ciphertext)+32)
concat[0] = version concat[0] = version
copy(concat[1:], nonce) copy(concat[1:], nonce[:])
copy(concat[1+32:], ciphertext) copy(concat[1+32:], ciphertext)
copy(concat[1+32+len(ciphertext):], mac) copy(concat[1+32+len(ciphertext):], mac)
@@ -99,27 +96,30 @@ func Encrypt(plaintext string, conversationKey [32]byte, applyOptions ...func(op
func Decrypt(b64ciphertextWrapped string, conversationKey [32]byte) (string, error) { func Decrypt(b64ciphertextWrapped string, conversationKey [32]byte) (string, error) {
cLen := len(b64ciphertextWrapped) cLen := len(b64ciphertextWrapped)
if cLen < 132 || cLen > 87472 { if cLen < 132 || cLen > 87472 {
return "", errors.New(fmt.Sprintf("invalid payload length: %d", cLen)) return "", fmt.Errorf(fmt.Sprintf("invalid payload length: %d", cLen))
} }
if b64ciphertextWrapped[0:1] == "#" { if b64ciphertextWrapped[0:1] == "#" {
return "", errors.New("unknown version") return "", fmt.Errorf("unknown version")
} }
decoded, err := base64.StdEncoding.DecodeString(b64ciphertextWrapped) decoded, err := base64.StdEncoding.DecodeString(b64ciphertextWrapped)
if err != nil { if err != nil {
return "", errors.New("invalid base64") return "", fmt.Errorf("invalid base64")
} }
if decoded[0] != version { if decoded[0] != version {
return "", errors.New(fmt.Sprintf("unknown version %d", decoded[0])) return "", fmt.Errorf(fmt.Sprintf("unknown version %d", decoded[0]))
} }
dLen := len(decoded) dLen := len(decoded)
if dLen < 99 || dLen > 65603 { if dLen < 99 || dLen > 65603 {
return "", errors.New(fmt.Sprintf("invalid data length: %d", dLen)) return "", fmt.Errorf(fmt.Sprintf("invalid data length: %d", dLen))
} }
nonce, ciphertext, givenMac := decoded[1:33], decoded[33:dLen-32], decoded[dLen-32:] var nonce [32]byte
copy(nonce[:], decoded[1:33])
ciphertext := decoded[33 : dLen-32]
givenMac := decoded[dLen-32:]
enc, cc20nonce, auth, err := messageKeys(conversationKey, nonce) enc, cc20nonce, auth, err := messageKeys(conversationKey, nonce)
if err != nil { if err != nil {
return "", err return "", err
@@ -131,7 +131,7 @@ func Decrypt(b64ciphertextWrapped string, conversationKey [32]byte) (string, err
} }
if !bytes.Equal(givenMac, expectedMac) { if !bytes.Equal(givenMac, expectedMac) {
return "", errors.New("invalid hmac") return "", fmt.Errorf("invalid hmac")
} }
padded, err := chacha(enc, cc20nonce, ciphertext) padded, err := chacha(enc, cc20nonce, ciphertext)
@@ -142,12 +142,12 @@ func Decrypt(b64ciphertextWrapped string, conversationKey [32]byte) (string, err
unpaddedLen := binary.BigEndian.Uint16(padded[0:2]) unpaddedLen := binary.BigEndian.Uint16(padded[0:2])
if unpaddedLen < uint16(MinPlaintextSize) || unpaddedLen > uint16(MaxPlaintextSize) || if unpaddedLen < uint16(MinPlaintextSize) || unpaddedLen > uint16(MaxPlaintextSize) ||
len(padded) != 2+calcPadding(int(unpaddedLen)) { len(padded) != 2+calcPadding(int(unpaddedLen)) {
return "", errors.New("invalid padding") return "", fmt.Errorf("invalid padding")
} }
unpadded := padded[2:][:unpaddedLen] unpadded := padded[2:][:unpaddedLen]
if len(unpadded) == 0 || len(unpadded) != int(unpaddedLen) { if len(unpadded) == 0 || len(unpadded) != int(unpaddedLen) {
return "", errors.New("invalid padding") return "", fmt.Errorf("invalid padding")
} }
return string(unpadded), nil return string(unpadded), nil
@@ -182,22 +182,15 @@ func chacha(key []byte, nonce []byte, message []byte) ([]byte, error) {
return dst, nil return dst, nil
} }
func sha256Hmac(key []byte, ciphertext []byte, nonce []byte) ([]byte, error) { func sha256Hmac(key []byte, ciphertext []byte, nonce [32]byte) ([]byte, error) {
if len(nonce) != 32 {
return nil, errors.New("nonce aad must be 32 bytes")
}
h := hmac.New(sha256.New, key) h := hmac.New(sha256.New, key)
h.Write(nonce) h.Write(nonce[:])
h.Write(ciphertext) h.Write(ciphertext)
return h.Sum(nil), nil return h.Sum(nil), nil
} }
func messageKeys(conversationKey [32]byte, nonce []byte) ([]byte, []byte, []byte, error) { func messageKeys(conversationKey [32]byte, nonce [32]byte) ([]byte, []byte, []byte, error) {
if len(nonce) != 32 { r := hkdf.Expand(sha256.New, conversationKey[:], nonce[:])
return nil, nil, nil, errors.New("nonce must be 32 bytes")
}
r := hkdf.Expand(sha256.New, conversationKey[:], nonce)
enc := make([]byte, 32) enc := make([]byte, 32)
if _, err := io.ReadFull(r, enc); err != nil { if _, err := io.ReadFull(r, enc); err != nil {
return nil, nil, nil, err return nil, nil, nil, err

View File

@@ -39,7 +39,7 @@ func GiftWrap(
if err != nil { if err != nil {
return nostr.Event{}, err return nostr.Event{}, err
} }
sealCiphertext, err := nip44.Encrypt(seal.String(), temporaryConversationKey, nil) sealCiphertext, err := nip44.Encrypt(seal.String(), temporaryConversationKey)
if err != nil { if err != nil {
return nostr.Event{}, err return nostr.Event{}, err
} }
@@ -57,8 +57,8 @@ func GiftWrap(
modify(&gw) modify(&gw)
} }
if err := seal.Sign(nonceKey); err != nil { if err := gw.Sign(nonceKey); err != nil {
return seal, err return gw, err
} }
return gw, nil return gw, nil