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Add hostname validation for JSSTrustManager
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The JSSTrustManager has been modified to take an optional
hostname attribute. If provided, it will be used to validate
the SAN extension or the cert subject DN.
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edewata committed Aug 9, 2024
1 parent 89a6e63 commit 1304825
Showing 1 changed file with 98 additions and 0 deletions.
Original file line number Diff line number Diff line change
Expand Up @@ -27,14 +27,26 @@
import java.util.Arrays;
import java.util.Collection;
import java.util.Enumeration;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

import javax.net.ssl.X509TrustManager;
import javax.security.auth.x500.X500Principal;

import org.mozilla.jss.CryptoManager;
import org.mozilla.jss.NotInitializedException;
import org.mozilla.jss.netscape.security.util.Cert;
import org.mozilla.jss.netscape.security.x509.CertificateSubjectName;
import org.mozilla.jss.netscape.security.x509.DNSName;
import org.mozilla.jss.netscape.security.x509.GeneralName;
import org.mozilla.jss.netscape.security.x509.GeneralNameInterface;
import org.mozilla.jss.netscape.security.x509.GeneralNames;
import org.mozilla.jss.netscape.security.x509.PKIXExtensions;
import org.mozilla.jss.netscape.security.x509.SubjectAlternativeNameExtension;
import org.mozilla.jss.netscape.security.x509.X500Name;
import org.mozilla.jss.netscape.security.x509.X509CertImpl;
import org.mozilla.jss.netscape.security.x509.X509CertInfo;
import org.mozilla.jss.pkcs11.PK11Cert;
import org.mozilla.jss.ssl.SSLCertificateApprovalCallback;
import org.mozilla.jss.ssl.SSLCertificateApprovalCallback.ValidityItem;
Expand All @@ -49,9 +61,18 @@ public class JSSTrustManager implements X509TrustManager {
public static final String SERVER_AUTH_OID = "1.3.6.1.5.5.7.3.1";
public static final String CLIENT_AUTH_OID = "1.3.6.1.5.5.7.3.2";

private String hostname;
private boolean allowMissingExtendedKeyUsage = false;
private SSLCertificateApprovalCallback callback;

public String getHostname() {
return hostname;
}

public void setHostname(String hostname) {
this.hostname = hostname;
}

public void configureAllowMissingExtendedKeyUsage(boolean allow) {
allowMissingExtendedKeyUsage = allow;
}
Expand All @@ -64,6 +85,81 @@ public void setCallback(SSLCertificateApprovalCallback certCallback) {
this.callback = certCallback;
}

public boolean isValidSAN(SubjectAlternativeNameExtension sanExt) throws Exception {

logger.debug("JSSTrustManager: Checking hostname in SAN extension");

if (sanExt == null) {
return false;
}

GeneralNames generalNames = sanExt.getGeneralNames();
Set<String> dnsNames = new HashSet<>();

for (GeneralNameInterface generalName : generalNames) {

if (generalName instanceof GeneralName) {
generalName = ((GeneralName) generalName).unwrap();
}

if (generalName instanceof DNSName) {
String dnsName = ((DNSName) generalName).getValue();
logger.debug("JSSTrustManager: - dns: " + dnsName);
dnsNames.add(dnsName.toLowerCase());
continue;
}
}

// TODO: add support for wildcards
return dnsNames.contains(hostname);
}

public boolean isValidSubject(CertificateSubjectName subject) throws Exception {

logger.debug("JSSTrustManager: Checking hostname in subject");

X500Name dn = (X500Name) subject.get(CertificateSubjectName.DN_NAME);
List<String> cns = dn.getAttributesForOid(X500Name.commonName_oid);

if (cns == null) {
return false;
}

for (String cn : cns) {
logger.debug("JSSTrustManager: - cn: " + cn);
}

// TODO: add support for wildcards
return cns.contains(hostname);
}

public void checkHostname(X509Certificate[] certChain, ValidityStatus status) throws Exception {

if (hostname == null) {
return;
}

// validating hostname on leaf cert only
X509Certificate leafCert = certChain[certChain.length - 1];
int depth = 0;

X509CertImpl certImpl = new X509CertImpl(leafCert.getEncoded());
SubjectAlternativeNameExtension sanExt = (SubjectAlternativeNameExtension) certImpl.getExtension(PKIXExtensions.SubjectAlternativeName_Id.toString());

if (isValidSAN(sanExt)) {
return;
}

X509CertInfo info = certImpl.getInfo();
CertificateSubjectName subject = (CertificateSubjectName) info.get(X509CertInfo.SUBJECT);

if (isValidSubject(subject)) {
return;
}

status.addReason(ValidityStatus.BAD_CERT_DOMAIN, leafCert, depth);
}

public void checkCertChain(X509Certificate[] certChain, String keyUsage) throws Exception {

logger.debug("JSSTrustManager: checkCertChain(" + keyUsage + ")");
Expand Down Expand Up @@ -113,6 +209,8 @@ public void checkCertChain(X509Certificate[] certChain, String keyUsage) throws

public void checkCertChain(X509Certificate[] certChain, String keyUsage, ValidityStatus status) throws Exception {

checkHostname(certChain, status);

if (!isTrustedPeer(certChain)) {
checkIssuerTrusted(certChain, status);
}
Expand Down

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