192 lines
7 KiB
Java
192 lines
7 KiB
Java
/*
|
|
* Copyright (C) 2017 Schürmann & Breitmoser GbR
|
|
*
|
|
* This program is free software: you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation, either version 3 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
package org.sufficientlysecure.keychain.pgp;
|
|
|
|
|
|
import java.util.regex.Matcher;
|
|
import java.util.regex.Pattern;
|
|
|
|
import android.support.annotation.CheckResult;
|
|
import android.support.annotation.NonNull;
|
|
import android.support.annotation.Nullable;
|
|
import android.support.annotation.VisibleForTesting;
|
|
import android.text.TextUtils;
|
|
|
|
import timber.log.Timber;
|
|
|
|
|
|
public class PgpHelper {
|
|
|
|
public static final Pattern PGP_MESSAGE = Pattern.compile(
|
|
".*?(-----BEGIN PGP MESSAGE-----.*?-----END PGP MESSAGE-----).*", Pattern.DOTALL);
|
|
|
|
public static final Pattern PGP_CLEARTEXT_SIGNATURE = Pattern
|
|
.compile(".*?(-----BEGIN PGP SIGNED MESSAGE-----.*?-----" +
|
|
"BEGIN PGP SIGNATURE-----.*?-----END PGP SIGNATURE-----).*",
|
|
Pattern.DOTALL);
|
|
|
|
public static final Pattern PGP_PUBLIC_KEY = Pattern.compile(
|
|
".*?(-----BEGIN PGP PUBLIC KEY BLOCK-----.*?-----END PGP PUBLIC KEY BLOCK-----).*",
|
|
Pattern.DOTALL);
|
|
private static final Pattern KEYDATA_START_PATTERN = Pattern.compile("\\s(m[A-Q])");
|
|
|
|
/**
|
|
* Fixing broken PGP MESSAGE Strings coming from GMail/AOSP Mail
|
|
*/
|
|
public static String fixPgpMessage(String message) {
|
|
// windows newline -> unix newline
|
|
message = message.replaceAll("\r\n", "\n");
|
|
// Mac OS before X newline -> unix newline
|
|
message = message.replaceAll("\r", "\n");
|
|
|
|
// remove whitespaces before newline
|
|
message = message.replaceAll(" +\n", "\n");
|
|
// only two consecutive newlines are allowed
|
|
message = message.replaceAll("\n\n+", "\n\n");
|
|
|
|
// replace non breakable spaces
|
|
message = message.replaceAll("\\xa0", " ");
|
|
|
|
return message;
|
|
}
|
|
|
|
/**
|
|
* Fixing broken PGP SIGNED MESSAGE Strings coming from GMail/AOSP Mail
|
|
*/
|
|
public static String fixPgpCleartextSignature(CharSequence input) {
|
|
if (!TextUtils.isEmpty(input)) {
|
|
String text = input.toString();
|
|
|
|
// windows newline -> unix newline
|
|
text = text.replaceAll("\r\n", "\n");
|
|
// Mac OS before X newline -> unix newline
|
|
text = text.replaceAll("\r", "\n");
|
|
|
|
return text;
|
|
} else {
|
|
return null;
|
|
}
|
|
}
|
|
|
|
public static String getPgpMessageContent(@NonNull CharSequence input) {
|
|
Timber.d("input: %s");
|
|
|
|
Matcher matcher = PgpHelper.PGP_MESSAGE.matcher(input);
|
|
if (matcher.matches()) {
|
|
String text = matcher.group(1);
|
|
text = fixPgpMessage(text);
|
|
|
|
Timber.d("input fixed: %s", text);
|
|
return text;
|
|
} else {
|
|
matcher = PgpHelper.PGP_CLEARTEXT_SIGNATURE.matcher(input);
|
|
if (matcher.matches()) {
|
|
String text = matcher.group(1);
|
|
text = fixPgpCleartextSignature(text);
|
|
|
|
Timber.d("input fixed: %s", text);
|
|
return text;
|
|
} else {
|
|
return null;
|
|
}
|
|
}
|
|
}
|
|
|
|
public static String getPgpPublicKeyContent(@NonNull CharSequence input) {
|
|
Timber.d("input: %s", input);
|
|
|
|
Matcher matcher = PgpHelper.PGP_PUBLIC_KEY.matcher(input);
|
|
if (!matcher.matches()) {
|
|
return null;
|
|
}
|
|
|
|
String text = matcher.group(1);
|
|
text = fixPgpMessage(text);
|
|
text = reformatPgpPublicKeyBlock(text);
|
|
|
|
// Log.dEscaped(Constants.TAG, "input fixed: " + text);
|
|
return text;
|
|
}
|
|
|
|
@Nullable
|
|
@CheckResult
|
|
@VisibleForTesting
|
|
/* Reformats a public key block with messed up whitespace. This will strip headers in the process. */
|
|
static String reformatPgpPublicKeyBlock(@NonNull String text) {
|
|
StringBuilder reformattedKeyBlocks = new StringBuilder();
|
|
|
|
/*
|
|
This method assumes that the base64 encoded public key data always starts with "m[A-Q]".
|
|
This holds based on a few assumptions based on the following observations:
|
|
|
|
mA encodes 12 bits: 1001 1000 0000
|
|
...
|
|
mP encodes 12 bits: 1001 1000 1111
|
|
mQ encodes 12 bits: 1001 1001 0000
|
|
1234 5678
|
|
|
|
The first bit is a constant 1, the second is 0 for old packet format. Bits 3
|
|
through 6 encode the packet tag (constant 6 = b0110). Bits 7 and 8 encode the
|
|
length type of the packet, with a value of b00 or b01 referring to a 2- or
|
|
3-octet header, respectively. The following four bits are part of the length
|
|
header.
|
|
|
|
Thus we make the following assumptions:
|
|
- The packet uses the old packet format. Since the public key packet tag is available in the old format,
|
|
there is no reason to use the new one - implementations *could* do that, however.
|
|
- The first packet is a public key.
|
|
- The length is encoded as one or two bytes.
|
|
- If the length is encoded as one byte, the second character may be A through P (four length bits).
|
|
- If the length is encoded as two bytes, the second character is Q. This fixes the first four bits of
|
|
the length field to zero, limiting the length to 4096.
|
|
*/
|
|
|
|
while (!text.isEmpty()) {
|
|
int indexOfBlock = text.indexOf("-----BEGIN PGP PUBLIC KEY BLOCK-----");
|
|
int indexOfBlockEnd = text.indexOf("-----END PGP PUBLIC KEY BLOCK-----");
|
|
if (indexOfBlock < 0 || indexOfBlockEnd < 0) {
|
|
break;
|
|
}
|
|
|
|
Matcher matcher = KEYDATA_START_PATTERN.matcher(text);
|
|
if (!matcher.find()) {
|
|
Timber.e("Could not find start of key data!");
|
|
break;
|
|
}
|
|
int indexOfPubkeyMaterial = matcher.start(1);
|
|
|
|
String keyMaterial = text.substring(indexOfPubkeyMaterial, indexOfBlockEnd);
|
|
keyMaterial = keyMaterial.replaceAll("\\s+", "\n");
|
|
|
|
reformattedKeyBlocks.append("-----BEGIN PGP PUBLIC KEY BLOCK-----\n");
|
|
reformattedKeyBlocks.append('\n');
|
|
reformattedKeyBlocks.append(keyMaterial);
|
|
reformattedKeyBlocks.append("-----END PGP PUBLIC KEY BLOCK-----\n");
|
|
|
|
text = text.substring(indexOfBlockEnd +34).trim();
|
|
}
|
|
|
|
if (reformattedKeyBlocks.length() == 0) {
|
|
return null;
|
|
}
|
|
|
|
return reformattedKeyBlocks.toString();
|
|
}
|
|
|
|
}
|