1package eu.siacs.conversations.crypto;
2
3import android.os.Build;
4import android.util.Log;
5import android.util.Pair;
6
7import org.bouncycastle.asn1.ASN1Primitive;
8import org.bouncycastle.asn1.DERIA5String;
9import org.bouncycastle.asn1.DERTaggedObject;
10import org.bouncycastle.asn1.DERUTF8String;
11import org.bouncycastle.asn1.DLSequence;
12import org.bouncycastle.asn1.x500.RDN;
13import org.bouncycastle.asn1.x500.X500Name;
14import org.bouncycastle.asn1.x500.style.BCStyle;
15import org.bouncycastle.asn1.x500.style.IETFUtils;
16import org.bouncycastle.cert.jcajce.JcaX509CertificateHolder;
17
18import java.io.IOException;
19import java.security.cert.Certificate;
20import java.security.cert.CertificateEncodingException;
21import java.security.cert.X509Certificate;
22import java.util.ArrayList;
23import java.util.Collection;
24import java.util.List;
25
26import javax.net.ssl.SSLSession;
27
28import de.duenndns.ssl.DomainHostnameVerifier;
29
30public class XmppDomainVerifier implements DomainHostnameVerifier {
31
32 private static final String LOGTAG = "XmppDomainVerifier";
33
34 private static final String SRV_NAME = "1.3.6.1.5.5.7.8.7";
35 private static final String XMPP_ADDR = "1.3.6.1.5.5.7.8.5";
36
37 @Override
38 public boolean verify(String domain, String hostname, SSLSession sslSession) {
39 try {
40 Certificate[] chain = sslSession.getPeerCertificates();
41 if (chain.length == 0 || !(chain[0] instanceof X509Certificate)) {
42 return false;
43 }
44 X509Certificate certificate = (X509Certificate) chain[0];
45 final List<String> commonNames = getCommonNames(certificate);
46 if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT && isSelfSigned(certificate)) {
47 if (commonNames.size() == 1 && matchDomain(domain,commonNames)) {
48 Log.d(LOGTAG,"accepted CN in self signed cert as work around for "+domain);
49 return true;
50 }
51 }
52 Collection<List<?>> alternativeNames = certificate.getSubjectAlternativeNames();
53 List<String> xmppAddrs = new ArrayList<>();
54 List<String> srvNames = new ArrayList<>();
55 List<String> domains = new ArrayList<>();
56 if (alternativeNames != null) {
57 for (List<?> san : alternativeNames) {
58 Integer type = (Integer) san.get(0);
59 if (type == 0) {
60 Pair<String, String> otherName = parseOtherName((byte[]) san.get(1));
61 if (otherName != null) {
62 switch (otherName.first) {
63 case SRV_NAME:
64 srvNames.add(otherName.second);
65 break;
66 case XMPP_ADDR:
67 xmppAddrs.add(otherName.second);
68 break;
69 default:
70 Log.d(LOGTAG, "oid: " + otherName.first + " value: " + otherName.second);
71 }
72 }
73 } else if (type == 2) {
74 Object value = san.get(1);
75 if (value instanceof String) {
76 domains.add((String) value);
77 }
78 }
79 }
80 }
81 if (srvNames.size() == 0 && xmppAddrs.size() == 0 && domains.size() == 0) {
82 domains.addAll(commonNames);
83 }
84 Log.d(LOGTAG, "searching for " + domain + " in srvNames: " + srvNames + " xmppAddrs: " + xmppAddrs + " domains:" + domains);
85 if (hostname != null) {
86 Log.d(LOGTAG,"also trying to verify hostname "+hostname);
87 }
88 return xmppAddrs.contains(domain)
89 || srvNames.contains("_xmpp-client." + domain)
90 || matchDomain(domain, domains)
91 || (hostname != null && matchDomain(hostname,domains));
92 } catch (Exception e) {
93 return false;
94 }
95 }
96
97 private static List<String> getCommonNames(X509Certificate certificate) {
98 List<String> domains = new ArrayList<>();
99 try {
100 X500Name x500name = new JcaX509CertificateHolder(certificate).getSubject();
101 RDN[] rdns = x500name.getRDNs(BCStyle.CN);
102 for (int i = 0; i < rdns.length; ++i) {
103 domains.add(IETFUtils.valueToString(x500name.getRDNs(BCStyle.CN)[i].getFirst().getValue()));
104 }
105 return domains;
106 } catch (CertificateEncodingException e) {
107 return domains;
108 }
109 }
110
111 private static Pair<String, String> parseOtherName(byte[] otherName) {
112 try {
113 ASN1Primitive asn1Primitive = ASN1Primitive.fromByteArray(otherName);
114 if (asn1Primitive instanceof DERTaggedObject) {
115 ASN1Primitive inner = ((DERTaggedObject) asn1Primitive).getObject();
116 if (inner instanceof DLSequence) {
117 DLSequence sequence = (DLSequence) inner;
118 if (sequence.size() >= 2 && sequence.getObjectAt(1) instanceof DERTaggedObject) {
119 String oid = sequence.getObjectAt(0).toString();
120 ASN1Primitive value = ((DERTaggedObject) sequence.getObjectAt(1)).getObject();
121 if (value instanceof DERUTF8String) {
122 return new Pair<>(oid, ((DERUTF8String) value).getString());
123 } else if (value instanceof DERIA5String) {
124 return new Pair<>(oid, ((DERIA5String) value).getString());
125 }
126 }
127 }
128 }
129 return null;
130 } catch (IOException e) {
131 return null;
132 }
133 }
134
135 private static boolean matchDomain(String needle, List<String> haystack) {
136 for (String entry : haystack) {
137 if (entry.startsWith("*.")) {
138 int i = needle.indexOf('.');
139 Log.d(LOGTAG, "comparing " + needle.substring(i) + " and " + entry.substring(1));
140 if (i != -1 && needle.substring(i).equals(entry.substring(1))) {
141 Log.d(LOGTAG, "domain " + needle + " matched " + entry);
142 return true;
143 }
144 } else {
145 if (entry.equals(needle)) {
146 Log.d(LOGTAG, "domain " + needle + " matched " + entry);
147 return true;
148 }
149 }
150 }
151 return false;
152 }
153
154 private boolean isSelfSigned(X509Certificate certificate) {
155 try {
156 certificate.verify(certificate.getPublicKey());
157 return true;
158 } catch (Exception e) {
159 return false;
160 }
161 }
162
163 @Override
164 public boolean verify(String domain, SSLSession sslSession) {
165 return verify(domain,null,sslSession);
166 }
167}