diff options
| -rw-r--r-- | build.gradle | 2 | ||||
| -rw-r--r-- | src/main/java/de/thedevstack/conversationsplus/ConversationsPlusApplication.java | 2 | ||||
| -rw-r--r-- | src/main/java/de/thedevstack/conversationsplus/utils/PRNGFixes.java | 328 |
3 files changed, 1 insertions, 331 deletions
diff --git a/build.gradle b/build.gradle index 739bca9a..63d9d710 100644 --- a/build.gradle +++ b/build.gradle @@ -76,7 +76,7 @@ android { buildToolsVersion '23.0.2' defaultConfig { - minSdkVersion 14 + minSdkVersion 19 targetSdkVersion 23 versionCode 10 versionName "0.0.8" diff --git a/src/main/java/de/thedevstack/conversationsplus/ConversationsPlusApplication.java b/src/main/java/de/thedevstack/conversationsplus/ConversationsPlusApplication.java index 2c056867..b70226e8 100644 --- a/src/main/java/de/thedevstack/conversationsplus/ConversationsPlusApplication.java +++ b/src/main/java/de/thedevstack/conversationsplus/ConversationsPlusApplication.java @@ -19,7 +19,6 @@ import de.thedevstack.conversationsplus.services.filetransfer.http.download.Http import de.thedevstack.conversationsplus.services.filetransfer.http.upload.HttpUploadFileTransferService; import de.thedevstack.conversationsplus.services.filetransfer.jingle.JingleFileTransferService; import de.thedevstack.conversationsplus.utils.ImageUtil; -import de.thedevstack.conversationsplus.utils.PRNGFixes; import de.thedevstack.conversationsplus.utils.SerialSingleThreadExecutor; /** @@ -55,7 +54,6 @@ public class ConversationsPlusApplication extends Application { * Initializes security features. */ private void initializeSecurity() { - PRNGFixes.apply(); this.secureRandom = new SecureRandom(); ConversationsPlusApplication.updateMemorizingTrustmanager(); } diff --git a/src/main/java/de/thedevstack/conversationsplus/utils/PRNGFixes.java b/src/main/java/de/thedevstack/conversationsplus/utils/PRNGFixes.java deleted file mode 100644 index 0751809c..00000000 --- a/src/main/java/de/thedevstack/conversationsplus/utils/PRNGFixes.java +++ /dev/null @@ -1,328 +0,0 @@ -package de.thedevstack.conversationsplus.utils; - -import android.os.Build; -import android.os.Process; - -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; - -import de.thedevstack.android.logcat.Logging; - -/** - * 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. - Logging.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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