diff options
author | iNPUTmice <daniel@gultsch.de> | 2014-06-20 17:30:19 +0200 |
---|---|---|
committer | iNPUTmice <daniel@gultsch.de> | 2014-06-20 17:30:19 +0200 |
commit | 1cf055d2fdbaa881cfc8ead6b78dc744e9dbe596 (patch) | |
tree | 51c0a3463ff3d5f005aeb6dccf6c50d05fddab42 /src/eu/siacs/conversations/utils | |
parent | beafb06b6a59649a4c314db820f5ce30be120e7c (diff) |
not working version of otr file transfer
Diffstat (limited to '')
-rw-r--r-- | src/eu/siacs/conversations/utils/CryptoHelper.java | 18 | ||||
-rw-r--r-- | src/eu/siacs/conversations/utils/PRNGFixes.java | 326 |
2 files changed, 336 insertions, 8 deletions
diff --git a/src/eu/siacs/conversations/utils/CryptoHelper.java b/src/eu/siacs/conversations/utils/CryptoHelper.java index ac189fc1..408c32fe 100644 --- a/src/eu/siacs/conversations/utils/CryptoHelper.java +++ b/src/eu/siacs/conversations/utils/CryptoHelper.java @@ -5,14 +5,14 @@ import java.nio.charset.Charset; import java.security.MessageDigest; import java.security.NoSuchAlgorithmException; import java.security.SecureRandom; -import java.util.Random; import eu.siacs.conversations.entities.Account; import android.util.Base64; public class CryptoHelper { - final protected static char[] hexArray = "0123456789ABCDEF".toCharArray(); + public static final String FILETRANSFER = "?FILETRANSFERv1:"; + final protected static char[] hexArray = "0123456789abcdef".toCharArray(); final protected static char[] vowels = "aeiou".toCharArray(); final protected static char[] consonants = "bcdfghjklmnpqrstvwxyz" .toCharArray(); @@ -24,7 +24,11 @@ public class CryptoHelper { hexChars[j * 2] = hexArray[v >>> 4]; hexChars[j * 2 + 1] = hexArray[v & 0x0F]; } - return new String(hexChars).toLowerCase(); + return new String(hexChars); + } + + public static byte[] hexToBytes(String hexString) { + return new BigInteger(hexString, 16).toByteArray(); } public static String saslPlain(String username, String password) { @@ -40,9 +44,8 @@ public class CryptoHelper { return result; } - public static String saslDigestMd5(Account account, String challenge) { + public static String saslDigestMd5(Account account, String challenge, SecureRandom random) { try { - Random random = new SecureRandom(); String[] challengeParts = new String(Base64.decode(challenge, Base64.DEFAULT)).split(","); String nonce = ""; @@ -84,12 +87,11 @@ public class CryptoHelper { } } - public static String randomMucName() { - Random random = new SecureRandom(); + public static String randomMucName(SecureRandom random) { return randomWord(3, random) + "." + randomWord(7, random); } - protected static String randomWord(int lenght, Random random) { + protected static String randomWord(int lenght, SecureRandom random) { StringBuilder builder = new StringBuilder(lenght); for (int i = 0; i < lenght; ++i) { if (i % 2 == 0) { diff --git a/src/eu/siacs/conversations/utils/PRNGFixes.java b/src/eu/siacs/conversations/utils/PRNGFixes.java new file mode 100644 index 00000000..cf28ff30 --- /dev/null +++ b/src/eu/siacs/conversations/utils/PRNGFixes.java @@ -0,0 +1,326 @@ +package eu.siacs.conversations.utils; + +import android.os.Build; +import android.os.Process; +import android.util.Log; + +import java.io.ByteArrayOutputStream; +import java.io.DataInputStream; +import java.io.DataOutputStream; +import java.io.File; +import java.io.FileInputStream; +import java.io.FileOutputStream; +import java.io.IOException; +import java.io.OutputStream; +import java.io.UnsupportedEncodingException; +import java.security.NoSuchAlgorithmException; +import java.security.Provider; +import java.security.SecureRandom; +import java.security.SecureRandomSpi; +import java.security.Security; + +/** + * Fixes for the output of the default PRNG having low entropy. + * + * The fixes need to be applied via {@link #apply()} before any use of Java + * Cryptography Architecture primitives. A good place to invoke them is in the + * application's {@code onCreate}. + */ +public final class PRNGFixes { + + private static final int VERSION_CODE_JELLY_BEAN = 16; + private static final int VERSION_CODE_JELLY_BEAN_MR2 = 18; + private static final byte[] BUILD_FINGERPRINT_AND_DEVICE_SERIAL = + getBuildFingerprintAndDeviceSerial(); + + /** Hidden constructor to prevent instantiation. */ + private PRNGFixes() {} + + /** + * Applies all fixes. + * + * @throws SecurityException if a fix is needed but could not be applied. + */ + public static void apply() { + applyOpenSSLFix(); + installLinuxPRNGSecureRandom(); + } + + /** + * Applies the fix for OpenSSL PRNG having low entropy. Does nothing if the + * fix is not needed. + * + * @throws SecurityException if the fix is needed but could not be applied. + */ + private static void applyOpenSSLFix() throws SecurityException { + if ((Build.VERSION.SDK_INT < VERSION_CODE_JELLY_BEAN) + || (Build.VERSION.SDK_INT > VERSION_CODE_JELLY_BEAN_MR2)) { + // No need to apply the fix + return; + } + + try { + // Mix in the device- and invocation-specific seed. + Class.forName("org.apache.harmony.xnet.provider.jsse.NativeCrypto") + .getMethod("RAND_seed", byte[].class) + .invoke(null, generateSeed()); + + // Mix output of Linux PRNG into OpenSSL's PRNG + int bytesRead = (Integer) Class.forName( + "org.apache.harmony.xnet.provider.jsse.NativeCrypto") + .getMethod("RAND_load_file", String.class, long.class) + .invoke(null, "/dev/urandom", 1024); + if (bytesRead != 1024) { + throw new IOException( + "Unexpected number of bytes read from Linux PRNG: " + + bytesRead); + } + } catch (Exception e) { + throw new SecurityException("Failed to seed OpenSSL PRNG", e); + } + } + + /** + * Installs a Linux PRNG-backed {@code SecureRandom} implementation as the + * default. Does nothing if the implementation is already the default or if + * there is not need to install the implementation. + * + * @throws SecurityException if the fix is needed but could not be applied. + */ + private static void installLinuxPRNGSecureRandom() + throws SecurityException { + if (Build.VERSION.SDK_INT > VERSION_CODE_JELLY_BEAN_MR2) { + // No need to apply the fix + return; + } + + // Install a Linux PRNG-based SecureRandom implementation as the + // default, if not yet installed. + Provider[] secureRandomProviders = + Security.getProviders("SecureRandom.SHA1PRNG"); + if ((secureRandomProviders == null) + || (secureRandomProviders.length < 1) + || (!LinuxPRNGSecureRandomProvider.class.equals( + secureRandomProviders[0].getClass()))) { + Security.insertProviderAt(new LinuxPRNGSecureRandomProvider(), 1); + } + + // Assert that new SecureRandom() and + // SecureRandom.getInstance("SHA1PRNG") return a SecureRandom backed + // by the Linux PRNG-based SecureRandom implementation. + SecureRandom rng1 = new SecureRandom(); + if (!LinuxPRNGSecureRandomProvider.class.equals( + rng1.getProvider().getClass())) { + throw new SecurityException( + "new SecureRandom() backed by wrong Provider: " + + rng1.getProvider().getClass()); + } + + SecureRandom rng2; + try { + rng2 = SecureRandom.getInstance("SHA1PRNG"); + } catch (NoSuchAlgorithmException e) { + throw new SecurityException("SHA1PRNG not available", e); + } + if (!LinuxPRNGSecureRandomProvider.class.equals( + rng2.getProvider().getClass())) { + throw new SecurityException( + "SecureRandom.getInstance(\"SHA1PRNG\") backed by wrong" + + " Provider: " + rng2.getProvider().getClass()); + } + } + + /** + * {@code Provider} of {@code SecureRandom} engines which pass through + * all requests to the Linux PRNG. + */ + private static class LinuxPRNGSecureRandomProvider extends Provider { + + public LinuxPRNGSecureRandomProvider() { + super("LinuxPRNG", + 1.0, + "A Linux-specific random number provider that uses" + + " /dev/urandom"); + // Although /dev/urandom is not a SHA-1 PRNG, some apps + // explicitly request a SHA1PRNG SecureRandom and we thus need to + // prevent them from getting the default implementation whose output + // may have low entropy. + put("SecureRandom.SHA1PRNG", LinuxPRNGSecureRandom.class.getName()); + put("SecureRandom.SHA1PRNG ImplementedIn", "Software"); + } + } + + /** + * {@link SecureRandomSpi} which passes all requests to the Linux PRNG + * ({@code /dev/urandom}). + */ + public static class LinuxPRNGSecureRandom extends SecureRandomSpi { + + /* + * IMPLEMENTATION NOTE: Requests to generate bytes and to mix in a seed + * are passed through to the Linux PRNG (/dev/urandom). Instances of + * this class seed themselves by mixing in the current time, PID, UID, + * build fingerprint, and hardware serial number (where available) into + * Linux PRNG. + * + * Concurrency: Read requests to the underlying Linux PRNG are + * serialized (on sLock) to ensure that multiple threads do not get + * duplicated PRNG output. + */ + + private static final File URANDOM_FILE = new File("/dev/urandom"); + + private static final Object sLock = new Object(); + + /** + * Input stream for reading from Linux PRNG or {@code null} if not yet + * opened. + * + * @GuardedBy("sLock") + */ + private static DataInputStream sUrandomIn; + + /** + * Output stream for writing to Linux PRNG or {@code null} if not yet + * opened. + * + * @GuardedBy("sLock") + */ + private static OutputStream sUrandomOut; + + /** + * Whether this engine instance has been seeded. This is needed because + * each instance needs to seed itself if the client does not explicitly + * seed it. + */ + private boolean mSeeded; + + @Override + protected void engineSetSeed(byte[] bytes) { + try { + OutputStream out; + synchronized (sLock) { + out = getUrandomOutputStream(); + } + out.write(bytes); + out.flush(); + } catch (IOException e) { + // On a small fraction of devices /dev/urandom is not writable. + // Log and ignore. + Log.w(PRNGFixes.class.getSimpleName(), + "Failed to mix seed into " + URANDOM_FILE); + } finally { + mSeeded = true; + } + } + + @Override + protected void engineNextBytes(byte[] bytes) { + if (!mSeeded) { + // Mix in the device- and invocation-specific seed. + engineSetSeed(generateSeed()); + } + + try { + DataInputStream in; + synchronized (sLock) { + in = getUrandomInputStream(); + } + synchronized (in) { + in.readFully(bytes); + } + } catch (IOException e) { + throw new SecurityException( + "Failed to read from " + URANDOM_FILE, e); + } + } + + @Override + protected byte[] engineGenerateSeed(int size) { + byte[] seed = new byte[size]; + engineNextBytes(seed); + return seed; + } + + private DataInputStream getUrandomInputStream() { + synchronized (sLock) { + if (sUrandomIn == null) { + // NOTE: Consider inserting a BufferedInputStream between + // DataInputStream and FileInputStream if you need higher + // PRNG output performance and can live with future PRNG + // output being pulled into this process prematurely. + try { + sUrandomIn = new DataInputStream( + new FileInputStream(URANDOM_FILE)); + } catch (IOException e) { + throw new SecurityException("Failed to open " + + URANDOM_FILE + " for reading", e); + } + } + return sUrandomIn; + } + } + + private OutputStream getUrandomOutputStream() throws IOException { + synchronized (sLock) { + if (sUrandomOut == null) { + sUrandomOut = new FileOutputStream(URANDOM_FILE); + } + return sUrandomOut; + } + } + } + + /** + * Generates a device- and invocation-specific seed to be mixed into the + * Linux PRNG. + */ + private static byte[] generateSeed() { + try { + ByteArrayOutputStream seedBuffer = new ByteArrayOutputStream(); + DataOutputStream seedBufferOut = + new DataOutputStream(seedBuffer); + seedBufferOut.writeLong(System.currentTimeMillis()); + seedBufferOut.writeLong(System.nanoTime()); + seedBufferOut.writeInt(Process.myPid()); + seedBufferOut.writeInt(Process.myUid()); + seedBufferOut.write(BUILD_FINGERPRINT_AND_DEVICE_SERIAL); + seedBufferOut.close(); + return seedBuffer.toByteArray(); + } catch (IOException e) { + throw new SecurityException("Failed to generate seed", e); + } + } + + /** + * Gets the hardware serial number of this device. + * + * @return serial number or {@code null} if not available. + */ + private static String getDeviceSerialNumber() { + // We're using the Reflection API because Build.SERIAL is only available + // since API Level 9 (Gingerbread, Android 2.3). + try { + return (String) Build.class.getField("SERIAL").get(null); + } catch (Exception ignored) { + return null; + } + } + + private static byte[] getBuildFingerprintAndDeviceSerial() { + StringBuilder result = new StringBuilder(); + String fingerprint = Build.FINGERPRINT; + if (fingerprint != null) { + result.append(fingerprint); + } + String serial = getDeviceSerialNumber(); + if (serial != null) { + result.append(serial); + } + try { + return result.toString().getBytes("UTF-8"); + } catch (UnsupportedEncodingException e) { + throw new RuntimeException("UTF-8 encoding not supported"); + } + } +}
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