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using Dino.Entities;
using Crypto;
using Signal;
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 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 {
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, key;
if (iv_and_key.length == 44) {
iv = iv_and_key[0:12];
key = iv_and_key[12:44];
} else {
iv = iv_and_key[0:16];
key = iv_and_key[16:48];
}
file_transfer.encryption = Encryption.OMEMO;
debug("Decrypting file %s from %s", file_transfer.file_name, file_transfer.server_file_name);
SymmetricCipher cipher = new SymmetricCipher("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);
}
}
}
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