mirror of https://github.com/M66B/FairEmail.git
M66B
3 years ago
parent
5c3309449e
commit
9db7dbcf09
@ -0,0 +1,235 @@
|
||||
package eu.faircode.email;
|
||||
|
||||
/*
|
||||
This file is part of FairEmail.
|
||||
|
||||
FairEmail 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.
|
||||
|
||||
FairEmail 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 FairEmail. If not, see <http://www.gnu.org/licenses/>.
|
||||
|
||||
Copyright 2018-2021 by Marcel Bokhorst (M66B)
|
||||
*/
|
||||
|
||||
import android.content.Context;
|
||||
import android.content.SharedPreferences;
|
||||
import android.graphics.Bitmap;
|
||||
import android.graphics.Color;
|
||||
import android.text.TextUtils;
|
||||
import android.util.Pair;
|
||||
|
||||
import androidx.preference.PreferenceManager;
|
||||
|
||||
import org.bouncycastle.asn1.x509.Extension;
|
||||
import org.bouncycastle.util.io.pem.PemObject;
|
||||
import org.bouncycastle.util.io.pem.PemReader;
|
||||
|
||||
import java.io.ByteArrayInputStream;
|
||||
import java.io.IOException;
|
||||
import java.io.InputStream;
|
||||
import java.io.InputStreamReader;
|
||||
import java.net.URL;
|
||||
import java.security.KeyStore;
|
||||
import java.security.cert.CertPathBuilder;
|
||||
import java.security.cert.CertPathBuilderResult;
|
||||
import java.security.cert.CertPathValidator;
|
||||
import java.security.cert.CertStore;
|
||||
import java.security.cert.CertStoreParameters;
|
||||
import java.security.cert.Certificate;
|
||||
import java.security.cert.CertificateFactory;
|
||||
import java.security.cert.CollectionCertStoreParameters;
|
||||
import java.security.cert.PKIXBuilderParameters;
|
||||
import java.security.cert.TrustAnchor;
|
||||
import java.security.cert.X509CertSelector;
|
||||
import java.security.cert.X509Certificate;
|
||||
import java.util.ArrayList;
|
||||
import java.util.Enumeration;
|
||||
import java.util.HashSet;
|
||||
import java.util.List;
|
||||
import java.util.Set;
|
||||
|
||||
import javax.net.ssl.HttpsURLConnection;
|
||||
|
||||
public class Bimi {
|
||||
// Beam me up, Scotty
|
||||
private static final int CONNECT_TIMEOUT = 10 * 1000; // milliseconds
|
||||
private static final int READ_TIMEOUT = 15 * 1000; // milliseconds
|
||||
private static final String OID_BrandIndicatorforMessageIdentification = "1.3.6.1.5.5.7.3.31";
|
||||
|
||||
static Pair<Bitmap, Boolean> get(Context context, String domain, String selector, int scaleToPixels)
|
||||
throws IOException {
|
||||
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(context);
|
||||
boolean bimi_vmc = prefs.getBoolean("bimi_vmc", false);
|
||||
|
||||
final String txt = selector + "._bimi." + domain;
|
||||
Log.i("BIMI fetch TXT=" + txt);
|
||||
DnsHelper.DnsRecord[] bimi = DnsHelper.lookup(context, txt, "txt");
|
||||
if (bimi.length == 0)
|
||||
return null;
|
||||
Log.i("BIMI got TXT=" + bimi[0].name);
|
||||
|
||||
Bitmap bitmap = null;
|
||||
boolean verified = !bimi_vmc;
|
||||
String[] params = bimi[0].name.split(";");
|
||||
for (String param : params) {
|
||||
String[] kv = param.split("=");
|
||||
if (kv.length != 2)
|
||||
continue;
|
||||
|
||||
switch (kv[0].trim().toLowerCase()) {
|
||||
case "v": { // Version
|
||||
String version = kv[1].trim();
|
||||
if (!"BIMI1".equalsIgnoreCase(version))
|
||||
Log.w("BIMI unsupported version=" + version);
|
||||
break;
|
||||
}
|
||||
|
||||
case "l": { // Image link
|
||||
if (!bimi_vmc)
|
||||
continue;
|
||||
|
||||
String svg = kv[1].trim();
|
||||
if (TextUtils.isEmpty(svg))
|
||||
continue;
|
||||
|
||||
URL url = new URL(svg);
|
||||
|
||||
Log.i("BIMI favicon " + url);
|
||||
HttpsURLConnection connection = (HttpsURLConnection) url.openConnection();
|
||||
connection.setRequestMethod("GET");
|
||||
connection.setReadTimeout(READ_TIMEOUT);
|
||||
connection.setConnectTimeout(CONNECT_TIMEOUT);
|
||||
connection.setInstanceFollowRedirects(true);
|
||||
connection.setRequestProperty("User-Agent", WebViewEx.getUserAgent(context));
|
||||
connection.connect();
|
||||
|
||||
try {
|
||||
bitmap = ImageHelper.renderSvg(
|
||||
connection.getInputStream(),
|
||||
Color.WHITE, scaleToPixels);
|
||||
} finally {
|
||||
connection.disconnect();
|
||||
}
|
||||
|
||||
break;
|
||||
}
|
||||
|
||||
case "a": { // Certificate link
|
||||
String a = kv[1].trim();
|
||||
if (TextUtils.isEmpty(a))
|
||||
continue;
|
||||
|
||||
URL url = new URL(a);
|
||||
|
||||
try {
|
||||
Log.i("BIMI PEM " + url);
|
||||
HttpsURLConnection connection = (HttpsURLConnection) url.openConnection();
|
||||
connection.setRequestMethod("GET");
|
||||
connection.setReadTimeout(READ_TIMEOUT);
|
||||
connection.setConnectTimeout(CONNECT_TIMEOUT);
|
||||
connection.setInstanceFollowRedirects(true);
|
||||
connection.setRequestProperty("User-Agent", WebViewEx.getUserAgent(context));
|
||||
connection.connect();
|
||||
|
||||
// Fetch PEM objects
|
||||
List<PemObject> pems = new ArrayList<>();
|
||||
try {
|
||||
InputStreamReader isr = new InputStreamReader(connection.getInputStream());
|
||||
PemReader reader = new PemReader(isr);
|
||||
while (true) {
|
||||
PemObject pem = reader.readPemObject();
|
||||
if (pem == null)
|
||||
break;
|
||||
else
|
||||
pems.add(pem);
|
||||
}
|
||||
} finally {
|
||||
connection.disconnect();
|
||||
}
|
||||
|
||||
if (pems.size() == 0)
|
||||
throw new IllegalArgumentException("No PEM objects");
|
||||
|
||||
// Convert to X.509 certificates
|
||||
List<X509Certificate> certs = new ArrayList<>();
|
||||
CertificateFactory fact = CertificateFactory.getInstance("X.509");
|
||||
for (PemObject pem : pems) {
|
||||
ByteArrayInputStream bis = new ByteArrayInputStream(pem.getContent());
|
||||
certs.add((X509Certificate) fact.generateCertificate(bis));
|
||||
}
|
||||
|
||||
// Get first certificate
|
||||
// https://datatracker.ietf.org/doc/draft-fetch-validation-vmc-wchuang/
|
||||
X509Certificate cert = certs.remove(0);
|
||||
|
||||
// Check certificate type
|
||||
List<String> ku = cert.getExtendedKeyUsage();
|
||||
if (!ku.contains(OID_BrandIndicatorforMessageIdentification))
|
||||
throw new IllegalArgumentException("Invalid certificate type");
|
||||
|
||||
// Check subject
|
||||
if (!EntityCertificate.getDnsNames(cert).contains(domain))
|
||||
throw new IllegalArgumentException("Invalid certificate domain");
|
||||
|
||||
// Get trust anchors
|
||||
Set<TrustAnchor> trustAnchors = new HashSet<>();
|
||||
for (String ca : context.getAssets().list(""))
|
||||
if (ca.endsWith(".pem")) {
|
||||
Log.i("Reading ca=" + ca);
|
||||
try (InputStream is = context.getAssets().open(ca)) {
|
||||
X509Certificate c = (X509Certificate) fact.generateCertificate(is);
|
||||
trustAnchors.add(new TrustAnchor(c, null));
|
||||
}
|
||||
}
|
||||
|
||||
KeyStore ks = KeyStore.getInstance("AndroidCAStore");
|
||||
ks.load(null, null);
|
||||
Enumeration<String> aliases = ks.aliases();
|
||||
while (aliases.hasMoreElements()) {
|
||||
String alias = aliases.nextElement();
|
||||
Certificate c = ks.getCertificate(alias);
|
||||
if (c instanceof X509Certificate)
|
||||
trustAnchors.add(new TrustAnchor((X509Certificate) c, null));
|
||||
}
|
||||
|
||||
// https://datatracker.ietf.org/doc/html/rfc3709#page-6
|
||||
// TODO: logoType
|
||||
byte[] logoType = cert.getExtensionValue(Extension.logoType.getId());
|
||||
|
||||
// Validate certificate
|
||||
X509CertSelector target = new X509CertSelector();
|
||||
target.setCertificate(cert);
|
||||
|
||||
PKIXBuilderParameters pparams = new PKIXBuilderParameters(trustAnchors, target);
|
||||
CertStoreParameters intermediates = new CollectionCertStoreParameters(certs);
|
||||
pparams.addCertStore(CertStore.getInstance("Collection", intermediates));
|
||||
pparams.setRevocationEnabled(false);
|
||||
pparams.setDate(null);
|
||||
|
||||
CertPathBuilder builder = CertPathBuilder.getInstance("PKIX");
|
||||
CertPathBuilderResult path = builder.build(pparams);
|
||||
|
||||
CertPathValidator cpv = CertPathValidator.getInstance("PKIX");
|
||||
cpv.validate(path.getCertPath(), pparams);
|
||||
|
||||
Log.i("BIMI valid domain=" + domain);
|
||||
verified = true;
|
||||
} catch (Throwable ex) {
|
||||
Log.w(new Throwable("BIMI", ex));
|
||||
}
|
||||
break;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
return (bitmap == null ? null : new Pair<>(bitmap, verified));
|
||||
}
|
||||
}
|
||||
Loading…
Reference in new issue