From c17f6be4446c67482da4cbb68e840e24caef016b Mon Sep 17 00:00:00 2001
From: M66B <M66B@users.noreply.github.com>
Date: Tue, 2 Mar 2021 13:52:52 +0100
Subject: [PATCH] p=p support for incoming messages

---
 FAQ.md                                        |  5 +-
 .../eu/faircode/email/FragmentMessages.java   | 46 +++++++++++++++++++
 2 files changed, 48 insertions(+), 3 deletions(-)

diff --git a/FAQ.md b/FAQ.md
index bbda8c4c6d..b7ea4dd2ff 100644
--- a/FAQ.md
+++ b/FAQ.md
@@ -819,9 +819,8 @@ You can decode S/MIME signatures, etc, [here](https://lapo.it/asn1js/).
 
 *pretty Easy privacy*
 
-pretty Easy privacy (p≡p) is not supported
-because there is still [no approved standard](https://tools.ietf.org/id/draft-birk-pep-00.html) for this
-and because hardly anyone uses this.
+There is still [no approved standard](https://tools.ietf.org/id/draft-birk-pep-00.html) for pretty Easy privacy (p≡p) and hardly anyone uses this.
+Nevertheless, FairEmail can properly decode incoming p≡p messages since version 1.1519.
 
 <br />
 
diff --git a/app/src/main/java/eu/faircode/email/FragmentMessages.java b/app/src/main/java/eu/faircode/email/FragmentMessages.java
index 4873b473b8..2844346417 100644
--- a/app/src/main/java/eu/faircode/email/FragmentMessages.java
+++ b/app/src/main/java/eu/faircode/email/FragmentMessages.java
@@ -208,6 +208,7 @@ import java.util.concurrent.Future;
 import javax.mail.Address;
 import javax.mail.MessageRemovedException;
 import javax.mail.MessagingException;
+import javax.mail.Part;
 import javax.mail.Session;
 import javax.mail.internet.InternetAddress;
 import javax.mail.internet.MimeMessage;
@@ -6244,6 +6245,8 @@ public class FragmentMessages extends FragmentBase implements SharedPreferences.
                                             }
                                         }
 
+                                        checkPep(message, remotes, context);
+
                                         db.message().setMessageEncrypt(message.id, parts.getEncryption());
                                         db.message().setMessageStored(message.id, new Date().getTime());
                                         db.message().setMessageFts(message.id, false);
@@ -6875,6 +6878,8 @@ public class FragmentMessages extends FragmentBase implements SharedPreferences.
                         Log.i("s/mime attachment=" + remote);
                     }
 
+                    checkPep(message, remotes, context);
+
                     db.message().setMessageEncrypt(message.id, parts.getEncryption());
                     db.message().setMessageStored(message.id, new Date().getTime());
                     db.message().setMessageFts(message.id, false);
@@ -6916,6 +6921,47 @@ public class FragmentMessages extends FragmentBase implements SharedPreferences.
         }.execute(this, args, "decrypt:s/mime");
     }
 
+    private static void checkPep(EntityMessage message, List<EntityAttachment> remotes, Context context) throws IOException, MessagingException {
+        DB db = DB.getInstance(context);
+        for (EntityAttachment remote : remotes)
+            if ("message/rfc822".equals(remote.getMimeType())) {
+                Properties props = MessageHelper.getSessionProperties();
+                Session isession = Session.getInstance(props, null);
+
+                MimeMessage pep;
+                try (InputStream fis = new FileInputStream(remote.getFile(context))) {
+                    pep = new MimeMessage(isession, fis);
+                }
+
+                String[] xpep = pep.getHeader("X-pEp-Wrapped-Message-Info");
+                if (xpep != null && xpep.length > 0 && "INNER".equals(xpep[0])) {
+                    MessageHelper phelper = new MessageHelper(pep, context);
+                    String spep = phelper.getSubject();
+                    if (!TextUtils.isEmpty(spep))
+                        db.message().setMessageSubject(message.id, spep);
+
+                    String shtml = phelper.getMessageParts().getHtml(context);
+                    if (!TextUtils.isEmpty(shtml)) {
+                        String html = Helper.readText(message.getFile(context));
+
+                        if (!TextUtils.isEmpty(html)) {
+                            EntityAttachment a = new EntityAttachment();
+                            a.message = message.id;
+                            a.sequence = remotes.size();
+                            a.type = "text/html";
+                            a.disposition = Part.INLINE;
+                            a.id = db.attachment().insertAttachment(a);
+
+                            Helper.writeText(a.getFile(context), html);
+                            db.attachment().setDownloaded(a.id, (long) html.length());
+                        }
+
+                        Helper.writeText(message.getFile(context), shtml);
+                    }
+                }
+            }
+    }
+
     private void onDelete(long id) {
         Bundle args = new Bundle();
         args.putLong("id", id);