func ExampleCipher() {
key, err := hex.DecodeString("60143a3d7c7137c3622d490e7dbb85859138d198d9c648960e186412a6250722")
if err != nil {
panic(err)
}
// A nonce should only be used once. Generate it randomly.
nonce, err := hex.DecodeString("308c92676fa95973")
if err != nil {
panic(err)
}
c, err := chacha20.New(key, nonce)
if err != nil {
panic(err)
}
src := []byte("hello I am a secret message")
dst := make([]byte, len(src))
c.XORKeyStream(dst, src)
fmt.Printf("%x\n", dst)
// Output:
// a05452ebd981422dcdab2c9cde0d20a03f769e87d3e976ee6d6a11
}
func TestBadNonceSize(t *testing.T) {
key := make([]byte, chacha20.KeySize)
nonce := make([]byte, 3)
_, err := chacha20.New(key, nonce)
if err != chacha20.ErrInvalidNonce {
t.Error("Should have rejected an invalid nonce")
}
}
func TestChaCha20(t *testing.T) {
for i, vector := range testVectors {
t.Logf("Running test vector %d", i)
key, err := hex.DecodeString(vector[0])
if err != nil {
t.Error(err)
}
nonce, err := hex.DecodeString(vector[1])
if err != nil {
t.Error(err)
}
c, err := chacha20.New(key, nonce)
if err != nil {
t.Error(err)
}
expected, err := hex.DecodeString(vector[2])
if err != nil {
t.Error(err)
}
src := make([]byte, len(expected))
dst := make([]byte, len(expected))
c.XORKeyStream(dst, src)
if !bytes.Equal(expected, dst) {
t.Errorf("Bad keystream: expected %x, was %x", expected, dst)
for i, v := range expected {
if dst[i] != v {
t.Logf("Mismatch at offset %d: %x vs %x", i, v, dst[i])
break
}
}
}
}
}
func (m *Mailer) HandleDelivery(next func(conn *smtpd.Connection)) func(conn *smtpd.Connection) {
return func(conn *smtpd.Connection) {
// Context variables
var (
isSpam = false
ctxID = uniuri.NewLen(uniuri.UUIDLen)
)
// Check for spam
spamReply, err := m.Spam.Report(string(conn.Envelope.Data))
if err != nil {
m.Log.WithFields(logrus.Fields{
"ctx_id": ctxID,
"err": err,
}).Error("Unable to check an email in spamd")
}
if spamReply != nil && spamReply.Code == spamc.EX_OK {
if spam, ok := spamReply.Vars["isSpam"]; ok && spam.(bool) {
isSpam = true
}
}
// Trim the spaces from the input
conn.Envelope.Data = bytes.TrimSpace(conn.Envelope.Data)
// First run the analysis algorithm to generate an email description
node := &models.EmailNode{}
if err := analyzeEmail(node, conn.Envelope.Data); err != nil {
m.Error(conn, err)
return
}
// Calculate message ID
messageID := node.Headers.Get("Message-ID")
x1i := strings.Index(messageID, "<")
if x1i != -1 {
x2i := strings.Index(messageID[x1i+1:], ">")
if x2i != -1 {
messageID = messageID[x1i+1 : x1i+x2i+1]
}
}
if messageID == "" {
messageID = uniuri.NewLen(uniuri.UUIDLen) + "@invalid-incoming.pgp.st"
}
// Generate the members field
fromHeader, err := mail.ParseAddress(node.Headers.Get("From"))
if err != nil {
m.Error(conn, err)
return
}
members := []string{fromHeader.Address}
toHeader, err := node.Headers.AddressList("From")
if err != nil {
m.Error(conn, err)
return
}
for _, to := range toHeader {
members = append(members, to.Address)
}
if x := node.Headers.Get("CC"); x != "" {
ccHeader, err := node.Headers.AddressList("CC")
if err != nil {
m.Error(conn, err)
return
}
for _, cc := range ccHeader {
members = append(members, cc.Address)
}
}
// Get the recipients list from the scope
recipients := conn.Environment["recipients"].([]recipient)
for _, recipient := range recipients {
// Parse the found key
keyring, err := openpgp.ReadKeyRing(bytes.NewReader(recipient.Key.Body))
if err != nil {
m.Error(conn, err)
return
}
// Prepare a new email object
email := &models.Email{
ID: uniuri.NewLen(uniuri.UUIDLen),
DateCreated: time.Now(),
DateModified: time.Now(),
Owner: recipient.Account.ID,
MessageID: messageID,
Status: "received",
}
// Generate a new key
key := make([]byte, 32)
if _, err := io.ReadFull(rand.Reader, key); err != nil {
m.Error(conn, err)
return
}
akey := [32]byte{}
copy(akey[:], key)
// Generate a new nonce
nonce := make([]byte, 8)
if _, err = rand.Read(nonce); err != nil {
m.Error(conn, err)
return
}
// Set up a new stream
stream, err := chacha20.New(key, nonce)
if err != nil {
m.Error(conn, err)
return
}
// Prepare output
ciphertext := make(
[]byte,
len(conn.Envelope.Data)+
chacha20.NonceSize+
(len(conn.Envelope.Data)/1024+1)*16,
)
// First write the nonce
copy(ciphertext[:chacha20.NonceSize], nonce)
// Then write the authenticated encrypted stream
oi := chacha20.NonceSize
for i := 0; i < len(conn.Envelope.Data); i += 1024 {
// Get the chunk
max := i + 1024
if max > len(conn.Envelope.Data) {
max = len(conn.Envelope.Data)
}
chunk := conn.Envelope.Data[i:max]
// Encrypt the block
stream.XORKeyStream(ciphertext[oi:oi+len(chunk)], chunk)
// Authenticate it
var out [16]byte
poly1305.Sum(&out, ciphertext[oi:oi+len(chunk)], &akey)
// Write it into the result
copy(ciphertext[oi+len(chunk):oi+len(chunk)+poly1305.TagSize], out[:])
// Increase the counter
oi += 1024 + poly1305.TagSize
}
// Save it to the body
email.Body = ciphertext
// Create a manifest and encrypt it
manifest, err := json.Marshal(models.Manifest{
Key: key,
Nonce: nonce,
Description: node,
})
if err != nil {
m.Error(conn, err)
return
}
encryptedManifest, err := utils.PGPEncrypt(manifest, keyring)
if err != nil {
m.Error(conn, err)
return
}
email.Manifest = encryptedManifest
// Match the thread
var thread *models.Thread
// Get the References header
var references string
if x := node.Headers.Get("In-Reply-To"); x != "" {
references = x
} else if x := node.Headers.Get("References"); x != "" {
references = x
}
// Match by Message-ID
if references != "" {
// As specified in http://www.jwz.org/doc/threading.html, first thing <> is the msg id
// We support both <message-id> and message-id format.
x1i := strings.Index(references, "<")
if x1i != -1 {
x2i := strings.Index(references[x1i+1:], ">")
if x2i != -1 {
references = references[x1i+1 : x1i+x2i+1]
}
}
// Look up the message ID in the database
cursor, err := r.Table("emails").GetAllByIndex("messageIDOwner", []interface{}{
references,
recipient.Account.ID,
}).CoerceTo("array").Do(func(emails r.Term) r.Term {
return r.Branch(
emails.Count().Eq(1),
r.Table("threads").Get(emails.Nth(0).Field("thread")).Default(map[string]interface{}{}),
map[string]interface{}{},
)
}).Run(m.Rethink)
if err != nil {
m.Error(conn, err)
return
}
defer cursor.Close()
if err := cursor.One(&thread); err != nil {
m.Error(conn, err)
return
}
// Check if we've found it, clear it if it's invalid
if thread.ID == "" {
thread = nil
}
}
// We can't match it by subject, so proceed to create a new thread
if thread == nil {
var secure string
if findEncrypted(node) {
secure = "all"
} else {
secure = "none"
}
labels := []string{recipient.Labels.Inbox}
if isSpam {
labels = append(labels, recipient.Labels.Spam)
}
thread = &models.Thread{
ID: uniuri.NewLen(uniuri.UUIDLen),
DateCreated: time.Now(),
DateModified: time.Now(),
Owner: recipient.Account.ID,
Labels: labels,
Members: members,
Secure: secure,
}
if err := r.Table("threads").Insert(thread).Exec(m.Rethink); err != nil {
m.Error(conn, err)
return
}
} else {
// Modify the existing thread
foundInbox := false
foundSpam := false
for _, label := range thread.Labels {
if label == recipient.Labels.Inbox {
foundInbox = true
}
if isSpam {
if label == recipient.Labels.Spam {
foundSpam = true
}
if foundInbox && foundSpam {
break
}
} else {
if foundInbox {
break
}
}
}
// Append to thread.Labels
if !foundInbox {
thread.Labels = append(thread.Labels, recipient.Labels.Inbox)
}
if !foundSpam && isSpam {
thread.Labels = append(thread.Labels, recipient.Labels.Spam)
}
// Members update
membersHash := map[string]struct{}{}
for _, member := range thread.Members {
membersHash[member] = struct{}{}
}
for _, member := range members {
if _, ok := membersHash[member]; !ok {
membersHash[member] = struct{}{}
}
}
thread.Members = []string{}
for member := range membersHash {
thread.Members = append(thread.Members, member)
}
update := map[string]interface{}{
"date_modified": time.Now(),
"is_read": false,
"labels": thread.Labels,
"members": thread.Members,
}
secure := findEncrypted(node)
if (thread.Secure == "all" && !secure) ||
(thread.Secure == "none" && secure) {
thread.Secure = "some"
}
if err := r.Table("threads").Get(thread.ID).Update(update).Exec(m.Rethink); err != nil {
m.Error(conn, err)
return
}
}
email.Thread = thread.ID
if err := r.Table("emails").Insert(email).Exec(m.Rethink); err != nil {
m.Error(conn, err)
return
}
m.Log.WithFields(logrus.Fields{
"address": recipient.Address.ID,
"account": recipient.Account.MainAddress,
}).Info("Email received")
}
next(conn)
}
}
func BenchmarkChaCha20(b *testing.B) {
key := make([]byte, chacha20.KeySize)
nonce := make([]byte, chacha20.NonceSize)
c, _ := chacha20.New(key, nonce)
benchmarkStream(b, c)
}
