Add decryptMime and refactor package structure

crypto/mime.go

@@ -0,0 +1,83 @@
+package crypto
+
+import (
+	"proton/pmmime"
+	"net/mail"
+	"strings"
+	"golang.org/x/crypto/openpgp/packet"
+	"net/textproto"
+	"io/ioutil"
+	"bytes"
+	"golang.org/x/crypto/openpgp"
+	"proton/pmcrypto/armor"
+)
+
+// ======================== Attachments Collector  ==============
+// Collect contents of all attachment parts and return
+// them as a string
+
+
+func (pm PmCrypto) parseMIME(mimeBody string, verifierKey []byte) (*pmmime.BodyCollector, int, []string, []string, error) {
+	pubKey := bytes.NewReader(verifierKey)
+	pubKeyEntries, err := openpgp.ReadKeyRing(pubKey)
+
+	mm, err := mail.ReadMessage(strings.NewReader(mimeBody))
+	if err != nil {
+		return nil, 0, nil, nil, err
+	}
+	config := &packet.Config{DefaultCipher: packet.CipherAES256, Time: pm.getTimeGenerator()}
+
+	h := textproto.MIMEHeader(mm.Header)
+	mmBodyData, err := ioutil.ReadAll(mm.Body)
+
+	printAccepter := pmmime.NewMIMEPrinter()
+	bodyCollector := pmmime.NewBodyCollector(printAccepter)
+	attachmentsCollector := pmmime.NewAttachmentsCollector(bodyCollector)
+	mimeVisitor := pmmime.NewMimeVisitor(attachmentsCollector)
+	str, err := armor.ArmorKey(verifierKey)
+	signatureCollector := newSignatureCollector(mimeVisitor, pubKeyEntries, config)
+	err = pmmime.VisitAll(bytes.NewReader(mmBodyData), h, signatureCollector)
+
+	verified := signatureCollector.verified
+	body := bodyCollector
+	atts := attachmentsCollector.GetAttachments()
+	attHeaders := attachmentsCollector.GetAttHeaders()
+
+	return body, verified, atts, attHeaders, nil
+}
+
+// define call back interface
+type MIMECallbacks interface {
+	OnBody(body string, mimetype string)
+	OnAttachment(headers string, data []byte)
+	// Encrypted headers can be an attachment and thus be placed at the end of the mime structure
+	OnEncryptedHeaders(headers string)
+	OnVerified(verified int)
+	OnError(err error)
+}
+
+func (pm *PmCrypto) DecryptMIMEMessage(encryptedText string, verifierKey []byte, privateKeys []byte,
+	passphrase string, callbacks MIMECallbacks, verifyTime int64) {
+	decsignverify, err := pm.decryptMessageVerifyAllBin(encryptedText, verifierKey, privateKeys, passphrase, verifyTime)
+	if err != nil {
+		callbacks.OnError(err)
+		return
+	}
+
+	body, verified, attachments, attachmentHeaders, err := pm.parseMIME(decsignverify.Plaintext, verifierKey)
+	if err != nil {
+		callbacks.OnError(err)
+		return
+	}
+	bodyContent, bodyMimeType := body.GetBody()
+	callbacks.OnBody(bodyContent, bodyMimeType)
+	for i := 0; i < len(attachments); i++ {
+		callbacks.OnAttachment(attachmentHeaders[i], []byte(attachments[i]))
+	}
+	callbacks.OnEncryptedHeaders("")
+	if decsignverify.Verify == notSigned {
+		callbacks.OnVerified(verified)
+	} else {
+		callbacks.OnVerified(decsignverify.Verify)
+	}
+}