Inital

2 files changed, 97 insertions, 0 deletions

diff --git a/app/crypto-openpgp/src/main/java/com/fsck/k9/crypto/openpgp/EncryptionDetector.java b/app/crypto-openpgp/src/main/java/com/fsck/k9/crypto/openpgp/EncryptionDetector.java
new file mode 100644
index 0000000..3605b51
--- /dev/null
+++ b/app/crypto-openpgp/src/main/java/com/fsck/k9/crypto/openpgp/EncryptionDetector.java
@@ -0,0 +1,67 @@
+package com.fsck.k9.crypto.openpgp;
+
+
+import androidx.annotation.NonNull;
+
+import com.fsck.k9.crypto.MessageCryptoStructureDetector;
+import com.fsck.k9.mail.Body;
+import com.fsck.k9.mail.BodyPart;
+import com.fsck.k9.mail.Message;
+import com.fsck.k9.mail.Multipart;
+import com.fsck.k9.mail.Part;
+import com.fsck.k9.message.extractors.TextPartFinder;
+
+import static com.fsck.k9.mail.internet.MimeUtility.isSameMimeType;
+
+
+//FIXME: Make this only detect OpenPGP messages. Move support for S/MIME messages to separate module.
+class EncryptionDetector {
+    private final TextPartFinder textPartFinder;
+
+
+    EncryptionDetector(TextPartFinder textPartFinder) {
+        this.textPartFinder = textPartFinder;
+    }
+
+    public boolean isEncrypted(@NonNull Message message) {
+        return isPgpMimeOrSMimeEncrypted(message) || containsInlinePgpEncryptedText(message);
+    }
+
+    private boolean isPgpMimeOrSMimeEncrypted(Message message) {
+        return containsPartWithMimeType(message, "multipart/encrypted", "application/pkcs7-mime");
+    }
+
+    private boolean containsInlinePgpEncryptedText(Message message) {
+        Part textPart = textPartFinder.findFirstTextPart(message);
+        return MessageCryptoStructureDetector.isPartPgpInlineEncrypted(textPart);
+    }
+
+    private boolean containsPartWithMimeType(Part part, String... wantedMimeTypes) {
+        String mimeType = part.getMimeType();
+        if (isMimeTypeAnyOf(mimeType, wantedMimeTypes)) {
+            return true;
+        }
+
+        Body body = part.getBody();
+        if (body instanceof Multipart) {
+            Multipart multipart = (Multipart) body;
+            for (BodyPart bodyPart : multipart.getBodyParts()) {
+                if (containsPartWithMimeType(bodyPart, wantedMimeTypes)) {
+                    return true;
+                }
+            }
+        }
+
+        return false;
+    }
+
+    private boolean isMimeTypeAnyOf(String mimeType, String... wantedMimeTypes) {
+        for (String wantedMimeType : wantedMimeTypes) {
+            if (isSameMimeType(mimeType, wantedMimeType)) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+}
diff --git a/app/crypto-openpgp/src/main/java/com/fsck/k9/crypto/openpgp/OpenPgpEncryptionExtractor.kt b/app/crypto-openpgp/src/main/java/com/fsck/k9/crypto/openpgp/OpenPgpEncryptionExtractor.kt
new file mode 100644
index 0000000..079114e
--- /dev/null
+++ b/app/crypto-openpgp/src/main/java/com/fsck/k9/crypto/openpgp/OpenPgpEncryptionExtractor.kt
@@ -0,0 +1,30 @@
+package com.fsck.k9.crypto.openpgp
+
+import com.fsck.k9.crypto.EncryptionExtractor
+import com.fsck.k9.crypto.EncryptionResult
+import com.fsck.k9.mail.Message
+import com.fsck.k9.message.extractors.TextPartFinder
+
+class OpenPgpEncryptionExtractor internal constructor(
+    private val encryptionDetector: EncryptionDetector
+) : EncryptionExtractor {
+
+    override fun extractEncryption(message: Message): EncryptionResult? {
+        return if (encryptionDetector.isEncrypted(message)) {
+            EncryptionResult(ENCRYPTION_TYPE, 0)
+        } else {
+            null
+        }
+    }
+
+    companion object {
+        const val ENCRYPTION_TYPE = "openpgp"
+
+        @JvmStatic
+        fun newInstance(): OpenPgpEncryptionExtractor {
+            val textPartFinder = TextPartFinder()
+            val encryptionDetector = EncryptionDetector(textPartFinder)
+            return OpenPgpEncryptionExtractor(encryptionDetector)
+        }
+    }
+}