mirror of
https://github.com/moparisthebest/open-keychain
synced 2024-11-23 17:22:16 -05:00
Updated PRNGFixes from official blogpost
This commit is contained in:
Dominik Schürmann
parent
0625061018
commit
bb657e4add
@ -350,7 +350,7 @@
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android:name=".ui.HelpActivity"
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android:label="@string/title_help" />
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<!-- Internal services/content provider (not exported) -->
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<!-- Internal services/content providers (not exported) -->
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<service
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android:name=".service.PassphraseCacheService"
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android:exported="false"
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@ -364,7 +364,7 @@
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android:authorities="org.sufficientlysecure.keychain.provider"
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android:exported="false" />
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<!-- Internal classes of OpenPGP (not exported) -->
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<!-- Internal classes of the remote APIs (not exported) -->
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<activity
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android:name="org.sufficientlysecure.keychain.service.remote.RemoteServiceActivity"
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android:exported="false"
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@ -398,7 +398,6 @@
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</service>
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<!-- Extended Remote API -->
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<service
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android:name="org.sufficientlysecure.keychain.service.remote.ExtendedApiService"
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android:enabled="true"
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@ -416,7 +415,7 @@
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<!-- TODO: authority! Make this API with content provider uris -->
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<!-- <provider -->
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<!-- android:name="org.sufficientlysecure.keychain.provider.KeychainServiceBlobProvider" -->
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<!-- android:authorities="org.sufficientlysecure.keychain.provider.apgserviceblobprovider" -->
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<!-- android:authorities="org.sufficientlysecure.keychain.provider.KeychainServiceBlobProvider" -->
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<!-- android:permission="org.sufficientlysecure.keychain.permission.ACCESS_API" /> -->
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</application>
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@ -12,13 +12,16 @@ package org.sufficientlysecure.keychain.util;
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import android.os.Build;
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import android.os.Process;
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import android.util.Log;
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import java.io.ByteArrayOutputStream;
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import java.io.DataInputStream;
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import java.io.DataOutputStream;
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import java.io.File;
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import java.io.FileInputStream;
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import java.io.FileOutputStream;
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import java.io.IOException;
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import java.io.OutputStream;
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import java.io.UnsupportedEncodingException;
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import java.security.NoSuchAlgorithmException;
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import java.security.Provider;
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@ -51,22 +54,27 @@ import java.security.Security;
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* random version, now Samsung's SELinux policy also prevents apps from opening
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* /dev/urandom for writing. Since we shouldn't need to write to /dev/urandom anyway
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* we now simply don't.
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*
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*
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* Sep 17, 2013:
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* Updated from official blogpost:
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* Update: the original code sample below crashed on a small fraction of Android
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* devices due to /dev/urandom not being writable. We have now updated the code sample to handle this case gracefully.
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*/
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public final class PRNGFixes {
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private static final int VERSION_CODE_JELLY_BEAN = 16;
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private static final int VERSION_CODE_JELLY_BEAN_MR2 = 18;
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private static final byte[] BUILD_FINGERPRINT_AND_DEVICE_SERIAL = getBuildFingerprintAndDeviceSerial();
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private static final byte[] BUILD_FINGERPRINT_AND_DEVICE_SERIAL =
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getBuildFingerprintAndDeviceSerial();
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/** Hidden constructor to prevent instantiation. */
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private PRNGFixes() {
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}
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private PRNGFixes() {}
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/**
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* Applies all fixes.
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*
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* @throws SecurityException
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* if a fix is needed but could not be applied.
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* @throws SecurityException if a fix is needed but could not be applied.
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*/
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public static void apply() {
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applyOpenSSLFix();
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@ -74,10 +82,10 @@ public final class PRNGFixes {
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}
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/**
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* Applies the fix for OpenSSL PRNG having low entropy. Does nothing if the fix is not needed.
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* Applies the fix for OpenSSL PRNG having low entropy. Does nothing if the
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* fix is not needed.
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*
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* @throws SecurityException
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* if the fix is needed but could not be applied.
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* @throws SecurityException if the fix is needed but could not be applied.
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*/
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private static void applyOpenSSLFix() throws SecurityException {
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if ((Build.VERSION.SDK_INT < VERSION_CODE_JELLY_BEAN)
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@ -89,16 +97,18 @@ public final class PRNGFixes {
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try {
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// Mix in the device- and invocation-specific seed.
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Class.forName("org.apache.harmony.xnet.provider.jsse.NativeCrypto")
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.getMethod("RAND_seed", byte[].class).invoke(null, generateSeed());
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.getMethod("RAND_seed", byte[].class)
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.invoke(null, generateSeed());
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// Mix output of Linux PRNG into OpenSSL's PRNG
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int bytesRead = (Integer) Class
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.forName("org.apache.harmony.xnet.provider.jsse.NativeCrypto")
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int bytesRead = (Integer) Class.forName(
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"org.apache.harmony.xnet.provider.jsse.NativeCrypto")
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.getMethod("RAND_load_file", String.class, long.class)
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.invoke(null, "/dev/urandom", 1024);
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if (bytesRead != 1024) {
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throw new IOException("Unexpected number of bytes read from Linux PRNG: "
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+ bytesRead);
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throw new IOException(
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"Unexpected number of bytes read from Linux PRNG: "
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+ bytesRead);
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}
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} catch (Exception e) {
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throw new SecurityException("Failed to seed OpenSSL PRNG", e);
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@ -106,14 +116,14 @@ public final class PRNGFixes {
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}
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/**
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* Installs a Linux PRNG-backed {@code SecureRandom} implementation as the default. Does nothing
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* if the implementation is already the default or if there is not need to install the
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* implementation.
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* Installs a Linux PRNG-backed {@code SecureRandom} implementation as the
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* default. Does nothing if the implementation is already the default or if
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* there is not need to install the implementation.
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*
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* @throws SecurityException
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* if the fix is needed but could not be applied.
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* @throws SecurityException if the fix is needed but could not be applied.
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*/
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private static void installLinuxPRNGSecureRandom() throws SecurityException {
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private static void installLinuxPRNGSecureRandom()
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throws SecurityException {
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if (Build.VERSION.SDK_INT > VERSION_CODE_JELLY_BEAN_MR2) {
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// No need to apply the fix
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return;
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@ -121,11 +131,12 @@ public final class PRNGFixes {
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// Install a Linux PRNG-based SecureRandom implementation as the
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// default, if not yet installed.
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Provider[] secureRandomProviders = Security.getProviders("SecureRandom.SHA1PRNG");
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Provider[] secureRandomProviders =
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Security.getProviders("SecureRandom.SHA1PRNG");
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if ((secureRandomProviders == null)
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|| (secureRandomProviders.length < 1)
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|| (!LinuxPRNGSecureRandomProvider.class
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.equals(secureRandomProviders[0].getClass()))) {
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|| (!LinuxPRNGSecureRandomProvider.class.equals(
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secureRandomProviders[0].getClass()))) {
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Security.insertProviderAt(new LinuxPRNGSecureRandomProvider(), 1);
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}
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@ -133,9 +144,11 @@ public final class PRNGFixes {
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// SecureRandom.getInstance("SHA1PRNG") return a SecureRandom backed
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// by the Linux PRNG-based SecureRandom implementation.
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SecureRandom rng1 = new SecureRandom();
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if (!LinuxPRNGSecureRandomProvider.class.equals(rng1.getProvider().getClass())) {
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throw new SecurityException("new SecureRandom() backed by wrong Provider: "
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+ rng1.getProvider().getClass());
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if (!LinuxPRNGSecureRandomProvider.class.equals(
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rng1.getProvider().getClass())) {
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throw new SecurityException(
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"new SecureRandom() backed by wrong Provider: "
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+ rng1.getProvider().getClass());
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}
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SecureRandom rng2;
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@ -144,22 +157,25 @@ public final class PRNGFixes {
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} catch (NoSuchAlgorithmException e) {
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throw new SecurityException("SHA1PRNG not available", e);
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}
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if (!LinuxPRNGSecureRandomProvider.class.equals(rng2.getProvider().getClass())) {
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throw new SecurityException("SecureRandom.getInstance(\"SHA1PRNG\") backed by wrong"
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if (!LinuxPRNGSecureRandomProvider.class.equals(
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rng2.getProvider().getClass())) {
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throw new SecurityException(
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"SecureRandom.getInstance(\"SHA1PRNG\") backed by wrong"
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+ " Provider: " + rng2.getProvider().getClass());
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}
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}
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/**
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* {@code Provider} of {@code SecureRandom} engines which pass through all requests to the Linux
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* PRNG.
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* {@code Provider} of {@code SecureRandom} engines which pass through
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* all requests to the Linux PRNG.
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*/
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@SuppressWarnings("serial")
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private static class LinuxPRNGSecureRandomProvider extends Provider {
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public LinuxPRNGSecureRandomProvider() {
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super("LinuxPRNG", 1.0, "A Linux-specific random number provider that uses"
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+ " /dev/urandom");
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super("LinuxPRNG",
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1.0,
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"A Linux-specific random number provider that uses"
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+ " /dev/urandom");
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// Although /dev/urandom is not a SHA-1 PRNG, some apps
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// explicitly request a SHA1PRNG SecureRandom and we thus need to
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// prevent them from getting the default implementation whose output
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@ -170,19 +186,21 @@ public final class PRNGFixes {
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}
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/**
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* {@link SecureRandomSpi} which passes all requests to the Linux PRNG ({@code /dev/urandom}).
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* {@link SecureRandomSpi} which passes all requests to the Linux PRNG
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* ({@code /dev/urandom}).
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*/
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@SuppressWarnings("serial")
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public static class LinuxPRNGSecureRandom extends SecureRandomSpi {
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/*
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* IMPLEMENTATION NOTE: Requests to generate bytes and to mix in a seed are passed through
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* to the Linux PRNG (/dev/urandom). Instances of this class seed themselves by mixing in
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* the current time, PID, UID, build fingerprint, and hardware serial number (where
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* available) into Linux PRNG.
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* IMPLEMENTATION NOTE: Requests to generate bytes and to mix in a seed
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* are passed through to the Linux PRNG (/dev/urandom). Instances of
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* this class seed themselves by mixing in the current time, PID, UID,
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* build fingerprint, and hardware serial number (where available) into
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* Linux PRNG.
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*
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* Concurrency: Read requests to the underlying Linux PRNG are serialized (on sLock) to
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* ensure that multiple threads do not get duplicated PRNG output.
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* Concurrency: Read requests to the underlying Linux PRNG are
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* serialized (on sLock) to ensure that multiple threads do not get
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* duplicated PRNG output.
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*/
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private static final File URANDOM_FILE = new File("/dev/urandom");
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@ -190,46 +208,53 @@ public final class PRNGFixes {
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private static final Object sLock = new Object();
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/**
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* Input stream for reading from Linux PRNG or {@code null} if not yet opened.
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* Input stream for reading from Linux PRNG or {@code null} if not yet
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* opened.
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*
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* @GuardedBy("sLock")
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*/
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private static DataInputStream sUrandomIn;
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// /**
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// * Output stream for writing to Linux PRNG or {@code null} if not yet opened.
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// *
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// * @GuardedBy("sLock")
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// */
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// private static OutputStream sUrandomOut;
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//
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// /**
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// * Whether this engine instance has been seeded. This is needed because each instance needs
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// * to seed itself if the client does not explicitly seed it.
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// */
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// private boolean mSeeded;
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/**
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* Output stream for writing to Linux PRNG or {@code null} if not yet
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* opened.
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*
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* @GuardedBy("sLock")
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*/
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private static OutputStream sUrandomOut;
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/**
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* Whether this engine instance has been seeded. This is needed because
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* each instance needs to seed itself if the client does not explicitly
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* seed it.
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*/
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private boolean mSeeded;
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@Override
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protected void engineSetSeed(byte[] bytes) {
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// try {
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// OutputStream out;
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// synchronized (sLock) {
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// out = getUrandomOutputStream();
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// }
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// out.write(bytes);
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// out.flush();
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// mSeeded = true;
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// } catch (IOException e) {
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// throw new SecurityException("Failed to mix seed into " + URANDOM_FILE, e);
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// }
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try {
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OutputStream out;
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synchronized (sLock) {
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out = getUrandomOutputStream();
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}
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out.write(bytes);
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out.flush();
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} catch (IOException e) {
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// On a small fraction of devices /dev/urandom is not writable.
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// Log and ignore.
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Log.w(PRNGFixes.class.getSimpleName(),
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"Failed to mix seed into " + URANDOM_FILE);
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} finally {
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mSeeded = true;
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}
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}
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@Override
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protected void engineNextBytes(byte[] bytes) {
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// if (!mSeeded) {
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// // Mix in the device- and invocation-specific seed.
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// engineSetSeed(generateSeed());
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// }
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if (!mSeeded) {
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// Mix in the device- and invocation-specific seed.
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engineSetSeed(generateSeed());
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}
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try {
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DataInputStream in;
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@ -240,7 +265,8 @@ public final class PRNGFixes {
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in.readFully(bytes);
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}
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} catch (IOException e) {
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throw new SecurityException("Failed to read from " + URANDOM_FILE, e);
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throw new SecurityException(
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"Failed to read from " + URANDOM_FILE, e);
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}
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}
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@ -259,38 +285,36 @@ public final class PRNGFixes {
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// PRNG output performance and can live with future PRNG
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// output being pulled into this process prematurely.
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try {
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sUrandomIn = new DataInputStream(new FileInputStream(URANDOM_FILE));
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sUrandomIn = new DataInputStream(
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new FileInputStream(URANDOM_FILE));
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} catch (IOException e) {
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throw new SecurityException("Failed to open " + URANDOM_FILE
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+ " for reading", e);
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throw new SecurityException("Failed to open "
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+ URANDOM_FILE + " for reading", e);
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}
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}
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return sUrandomIn;
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}
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}
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// private OutputStream getUrandomOutputStream() {
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// synchronized (sLock) {
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// if (sUrandomOut == null) {
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// try {
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// sUrandomOut = new FileOutputStream(URANDOM_FILE);
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// } catch (IOException e) {
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// throw new SecurityException("Failed to open " + URANDOM_FILE
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// + " for writing", e);
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// }
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// }
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// return sUrandomOut;
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// }
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// }
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private OutputStream getUrandomOutputStream() throws IOException {
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synchronized (sLock) {
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if (sUrandomOut == null) {
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sUrandomOut = new FileOutputStream(URANDOM_FILE);
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}
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return sUrandomOut;
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}
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}
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}
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/**
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* Generates a device- and invocation-specific seed to be mixed into the Linux PRNG.
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* Generates a device- and invocation-specific seed to be mixed into the
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* Linux PRNG.
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*/
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private static byte[] generateSeed() {
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try {
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ByteArrayOutputStream seedBuffer = new ByteArrayOutputStream();
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DataOutputStream seedBufferOut = new DataOutputStream(seedBuffer);
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DataOutputStream seedBufferOut =
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new DataOutputStream(seedBuffer);
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seedBufferOut.writeLong(System.currentTimeMillis());
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seedBufferOut.writeLong(System.nanoTime());
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seedBufferOut.writeInt(Process.myPid());
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Reference in New Issue
Block a user