2 files changed, 166 insertions, 0 deletions
diff --git a/main/src/plugins/omemo/file_transfer/file_decryptor.vala b/main/src/plugins/omemo/file_transfer/file_decryptor.vala
new file mode 100644
index 00000000..8ae0b96b
--- /dev/null
+++ b/main/src/plugins/omemo/file_transfer/file_decryptor.vala
@@ -0,0 +1,90 @@
+using Dino.Entities;
+
+using Dino.Crypto;
+using Omemo;
+
+namespace Dino.Plugins.Omemo {
+
+public class OmemoHttpFileReceiveData : HttpFileReceiveData {
+    public string original_url;
+}
+
+public class OmemoFileDecryptor : FileDecryptor, Object {
+
+    private Regex url_regex = /^aesgcm:\/\/(.*)#(([A-Fa-f0-9]{2}){48}|([A-Fa-f0-9]{2}){44})$/;
+
+    public Encryption get_encryption() {
+        return Encryption.OMEMO;
+    }
+
+    public FileReceiveData prepare_get_meta_info(Conversation conversation, FileTransfer file_transfer, FileReceiveData receive_data) {
+        HttpFileReceiveData? http_receive_data = receive_data as HttpFileReceiveData;
+        if (http_receive_data == null) assert(false);
+        if ((receive_data as OmemoHttpFileReceiveData) != null) return receive_data;
+
+        var omemo_http_receive_data = new OmemoHttpFileReceiveData();
+        omemo_http_receive_data.url = aesgcm_to_https_link(http_receive_data.url);
+        omemo_http_receive_data.original_url = http_receive_data.url;
+
+        return omemo_http_receive_data;
+    }
+
+    public FileMeta prepare_download_file(Conversation conversation, FileTransfer file_transfer, FileReceiveData receive_data, FileMeta file_meta) {
+        if (file_meta.file_name != null) {
+            file_meta.file_name = file_meta.file_name.split("#")[0];
+        }
+        return file_meta;
+    }
+
+    public bool can_decrypt_file(Conversation conversation, FileTransfer file_transfer, FileReceiveData receive_data) {
+        HttpFileReceiveData? http_file_receive = receive_data as HttpFileReceiveData;
+        if (http_file_receive == null) return false;
+
+        return this.url_regex.match(http_file_receive.url) || (receive_data as OmemoHttpFileReceiveData) != null;
+    }
+
+    public async InputStream decrypt_file(InputStream encrypted_stream, Conversation conversation, FileTransfer file_transfer, FileReceiveData receive_data) throws FileReceiveError {
+        const uint KEY_SIZE = 32;
+        try {
+            OmemoHttpFileReceiveData? omemo_http_receive_data = receive_data as OmemoHttpFileReceiveData;
+            if (omemo_http_receive_data == null) assert(false);
+
+            // Decode IV and key
+            MatchInfo match_info;
+            this.url_regex.match(omemo_http_receive_data.original_url, 0, out match_info);
+            uint8[] iv_and_key = hex_to_bin(match_info.fetch(2).up());
+            uint8[] iv = iv_and_key[0:iv_and_key.length-KEY_SIZE];
+            uint8[] key = iv_and_key[iv_and_key.length-KEY_SIZE:iv_and_key.length];
+
+            file_transfer.encryption = Encryption.OMEMO;
+            debug("Decrypting file %s from %s", file_transfer.file_name, file_transfer.server_file_name);
+
+            SymmetricCipherDecryption cipher = create_symmetric_cipher_decryption("AES-GCM");
+            cipher.set_key(key);
+            cipher.set_iv(iv);
+            return new ConverterInputStream(encrypted_stream, new SymmetricCipherDecrypter((owned) cipher, 16));
+
+        } catch (Crypto.Error e) {
+            throw new FileReceiveError.DECRYPTION_FAILED("OMEMO file decryption error: %s".printf(e.message));
+        } catch (GLib.Error e) {
+            throw new FileReceiveError.DECRYPTION_FAILED("OMEMO file decryption error: %s".printf(e.message));
+        }
+    }
+
+    private uint8[] hex_to_bin(string hex) {
+        uint8[] bin = new uint8[hex.length / 2];
+        const string HEX = "0123456789ABCDEF";
+        for (int i = 0; i < hex.length / 2; i++) {
+            bin[i] = (uint8) (HEX.index_of_char(hex[i*2]) << 4) | HEX.index_of_char(hex[i*2+1]);
+        }
+        return bin;
+    }
+
+    private string aesgcm_to_https_link(string aesgcm_link) {
+        MatchInfo match_info;
+        this.url_regex.match(aesgcm_link, 0, out match_info);
+        return "https://" + match_info.fetch(1);
+    }
+}
+
+}
diff --git a/main/src/plugins/omemo/file_transfer/file_encryptor.vala b/main/src/plugins/omemo/file_transfer/file_encryptor.vala
new file mode 100644
index 00000000..5f1d6e69
--- /dev/null
+++ b/main/src/plugins/omemo/file_transfer/file_encryptor.vala
@@ -0,0 +1,76 @@
+using Gee;
+using Gtk;
+
+using Dino.Crypto;
+using Dino.Entities;
+using Xmpp;
+using Omemo;
+
+namespace Dino.Plugins.Omemo {
+
+public class OmemoHttpFileMeta : HttpFileMeta {
+    public uint8[] iv;
+    public uint8[] key;
+}
+
+public class OmemoFileEncryptor : Dino.FileEncryptor, Object {
+
+    public bool can_encrypt_file(Conversation conversation, FileTransfer file_transfer) {
+        return file_transfer.encryption == Encryption.OMEMO;
+    }
+
+    public FileMeta encrypt_file(Conversation conversation, FileTransfer file_transfer) throws FileSendError {
+        const uint KEY_SIZE = 32;
+        const uint IV_SIZE = 12;
+        var omemo_http_file_meta = new OmemoHttpFileMeta();
+
+        try {
+            //Create a key and use it to encrypt the file
+            uint8[] iv = new uint8[IV_SIZE];
+            Crypto.randomize(iv);
+            uint8[] key = new uint8[KEY_SIZE];
+            Crypto.randomize(key);
+
+            SymmetricCipherEncryption cipher = create_symmetric_cipher_encryption("AES-GCM");
+            cipher.set_key(key);
+            cipher.set_iv(iv);
+
+            omemo_http_file_meta.iv = iv;
+            omemo_http_file_meta.key = key;
+            omemo_http_file_meta.size = file_transfer.size + 16;
+            omemo_http_file_meta.content_type = new FileContentType.from_mime_type("application/octet-stream");
+            file_transfer.input_stream = new ConverterInputStream(file_transfer.input_stream, new SymmetricCipherEncrypter((owned) cipher, 16));
+        } catch (Crypto.Error error) {
+            throw new FileSendError.ENCRYPTION_FAILED("OMEMO file encryption error: %s".printf(error.message));
+        } catch (GLib.Error error) {
+            throw new FileSendError.ENCRYPTION_FAILED("OMEMO file encryption error: %s".printf(error.message));
+        }
+
+        debug("Encrypting file %s as %s", file_transfer.file_name, file_transfer.server_file_name);
+
+        return omemo_http_file_meta;
+    }
+
+    public FileSendData? preprocess_send_file(Conversation conversation, FileTransfer file_transfer, FileSendData file_send_data, FileMeta file_meta) {
+        HttpFileSendData? send_data = file_send_data as HttpFileSendData;
+        if (send_data == null) return null;
+
+        OmemoHttpFileMeta? omemo_http_file_meta = file_meta as OmemoHttpFileMeta;
+        if (omemo_http_file_meta == null) return null;
+
+        // Convert iv and key to hex
+        string iv_and_key = "";
+        foreach (uint8 byte in omemo_http_file_meta.iv) iv_and_key += byte.to_string("%02x");
+        foreach (uint8 byte in omemo_http_file_meta.key) iv_and_key += byte.to_string("%02x");
+
+        string aesgcm_link = send_data.url_down + "#" + iv_and_key;
+        aesgcm_link = "aesgcm://" + aesgcm_link.substring(8); // replace https:// by aesgcm://
+
+        send_data.url_down = aesgcm_link;
+        send_data.encrypt_message = true;
+
+        return file_send_data;
+    }
+}
+
+}