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