diff --git a/src/com/fsck/k9/net/ssl/TrustedSocketFactory.java b/src/com/fsck/k9/net/ssl/TrustedSocketFactory.java index acb9c7574..d24926def 100644 --- a/src/com/fsck/k9/net/ssl/TrustedSocketFactory.java +++ b/src/com/fsck/k9/net/ssl/TrustedSocketFactory.java @@ -13,46 +13,67 @@ import java.util.*; /** * Filter and reorder list of cipher suites and TLS versions. - * - *

- * See: http://op-co.de/blog/posts/android_ssl_downgrade/ - *

*/ public class TrustedSocketFactory { protected static final String ENABLED_CIPHERS[]; protected static final String ENABLED_PROTOCOLS[]; - static { - String preferredCiphers[] = { - "TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA", - "TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA", + // Order taken from OpenSSL 1.0.1c + protected static final String ORDERED_KNOWN_CIPHERS[] = { "TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA", "TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA", - "TLS_DHE_RSA_WITH_AES_128_CBC_SHA", "TLS_DHE_RSA_WITH_AES_256_CBC_SHA", + "TLS_DHE_DSS_WITH_AES_256_CBC_SHA", + "TLS_ECDH_RSA_WITH_AES_256_CBC_SHA", + "TLS_ECDH_ECDSA_WITH_AES_256_CBC_SHA", + "TLS_RSA_WITH_AES_256_CBC_SHA", + "TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA", + "TLS_ECDHE_ECDSA_WITH_3DES_EDE_CBC_SHA", + "TLS_ECDH_RSA_WITH_3DES_EDE_CBC_SHA", + "TLS_ECDH_ECDSA_WITH_3DES_EDE_CBC_SHA", + "SSL_RSA_WITH_3DES_EDE_CBC_SHA", + "TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA", + "TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA", + "TLS_DHE_RSA_WITH_AES_128_CBC_SHA", "TLS_DHE_DSS_WITH_AES_128_CBC_SHA", + "TLS_ECDH_RSA_WITH_AES_128_CBC_SHA", + "TLS_ECDH_ECDSA_WITH_AES_128_CBC_SHA", + "TLS_RSA_WITH_AES_128_CBC_SHA", "TLS_ECDHE_RSA_WITH_RC4_128_SHA", "TLS_ECDHE_ECDSA_WITH_RC4_128_SHA", - "TLS_RSA_WITH_AES_128_CBC_SHA", - "TLS_RSA_WITH_AES_256_CBC_SHA", - "SSL_RSA_WITH_3DES_EDE_CBC_SHA", + "TLS_ECDH_RSA_WITH_RC4_128_SHA", + "TLS_ECDH_ECDSA_WITH_RC4_128_SHA", + "SSL_DHE_RSA_WITH_3DES_EDE_CBC_SHA", + "SSL_DHE_DSS_WITH_3DES_EDE_CBC_SHA", "SSL_RSA_WITH_RC4_128_SHA", "SSL_RSA_WITH_RC4_128_MD5", - }; - String preferredProtocols[] = { - "TLSv1.2", "TLSv1.1", "TLSv1" - }; + }; - String[] supportedCiphers = null; - String[] supportedProtocols = null; + protected static final String[] BLACKLISTED_CIPHERS = { + "SSL_RSA_WITH_DES_CBC_SHA", + "SSL_DHE_RSA_WITH_DES_CBC_SHA", + "SSL_DHE_DSS_WITH_DES_CBC_SHA", + "SSL_RSA_EXPORT_WITH_RC4_40_MD5", + "SSL_RSA_EXPORT_WITH_DES40_CBC_SHA", + "SSL_DHE_RSA_EXPORT_WITH_DES40_CBC_SHA", + "SSL_DHE_DSS_EXPORT_WITH_DES40_CBC_SHA", + }; + + protected static final String ORDERED_KNOWN_PROTOCOLS[] = { + "TLSv1.2", "TLSv1.1", "TLSv1", "SSLv3" + }; + + static { + String[] enabledCiphers = null; + String[] enabledProtocols = null; try { SSLContext sslContext = SSLContext.getInstance("TLS"); sslContext.init(null, null, new SecureRandom()); SSLSocketFactory sf = sslContext.getSocketFactory(); - supportedCiphers = sf.getSupportedCipherSuites(); - SSLSocket sock = (SSLSocket)sf.createSocket(); - supportedProtocols = sock.getSupportedProtocols(); + SSLSocket sock = (SSLSocket) sf.createSocket(); + enabledCiphers = sock.getEnabledCipherSuites(); + enabledProtocols = sock.getEnabledProtocols(); } catch (IOException ioe) { ioe.printStackTrace(); } catch (KeyManagementException kme) { @@ -61,21 +82,37 @@ public class TrustedSocketFactory { nsae.printStackTrace(); } - ENABLED_CIPHERS = supportedCiphers == null ? null : - filterBySupport(preferredCiphers, supportedCiphers); - ENABLED_PROTOCOLS = supportedProtocols == null ? null : - filterBySupport(preferredProtocols, supportedProtocols); + ENABLED_CIPHERS = (enabledCiphers == null) ? null : + reorder(enabledCiphers, ORDERED_KNOWN_CIPHERS, BLACKLISTED_CIPHERS); + + ENABLED_PROTOCOLS = (enabledProtocols == null) ? null : + reorder(enabledProtocols, ORDERED_KNOWN_PROTOCOLS, null); } - protected static String[] filterBySupport(String[] preferred, String[] supported) { - List enabled = new ArrayList(); - Set available = new HashSet(); - Collections.addAll(available, supported); + protected static String[] reorder(String[] enabled, String[] known, String[] blacklisted) { + List unknown = new ArrayList(); + Collections.addAll(unknown, enabled); - for (String item : preferred) { - if (available.contains(item)) enabled.add(item); + // Remove blacklisted items + if (blacklisted != null) { + for (String item : blacklisted) { + unknown.remove(item); + } } - return enabled.toArray(new String[enabled.size()]); + + // Order known items + List result = new ArrayList(); + for (String item : known) { + if (unknown.remove(item)) { + result.add(item); + } + } + + // Add unknown items at the end. This way security won't get worse when unknown ciphers + // start showing up in the future. + result.addAll(unknown); + + return result.toArray(new String[result.size()]); } public static Socket createSocket(SSLContext sslContext) throws IOException {