Add net/android/keystore.h

net/android/java/src/org/chromium/net/AndroidKeyStore.java

Index: net/android/java/src/org/chromium/net/AndroidKeyStore.java
diff --git a/net/android/java/src/org/chromium/net/AndroidKeyStore.java b/net/android/java/src/org/chromium/net/AndroidKeyStore.java
new file mode 100644
index 0000000000000000000000000000000000000000..26e8247ff39f9a39c87a2cadf86f5278dfca900b
--- /dev/null
+++ b/net/android/java/src/org/chromium/net/AndroidKeyStore.java
@@ -0,0 +1,314 @@
+// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.net;
+
+import android.util.Log;
+
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.math.BigInteger;
+import java.security.interfaces.DSAKey;
+import java.security.interfaces.DSAPrivateKey;
+import java.security.interfaces.DSAParams;
+import java.security.interfaces.ECKey;
+import java.security.interfaces.ECPrivateKey;
+import java.security.interfaces.RSAKey;
+import java.security.interfaces.RSAPrivateKey;
+import java.security.NoSuchAlgorithmException;
+import java.security.PrivateKey;
+import java.security.Signature;
+import java.security.spec.ECParameterSpec;
+
+import org.chromium.base.CalledByNative;
+import org.chromium.base.JNINamespace;
+import org.chromium.net.PrivateKeyType;;
+
+@JNINamespace("net::android")
+public class AndroidKeyStore {
+
+    private static final String TAG = AndroidKeyStore.class.getName();
+
+    ////////////////////////////////////////////////////////////////////
+    //
+    // Message signing support.
+
+    /**
+     * Returns the public modulus of a given RSA private key as a byte
+     * buffer.
+     * This can be used by native code to convert the modulus into
+     * an OpenSSL BIGNUM object. Required to craft a custom native RSA
+     * object where RSA_size() works as expected.
+     *
+     * @param key A PrivateKey instance, must implement RSAKey.
+     * @return A byte buffer corresponding to the modulus. This is
+     * big-endian representation of a BigInteger.
+     */
+    @CalledByNative
+    public static byte[] getRSAKeyModulus(PrivateKey key) {
+        if (key instanceof RSAKey) {
+            return ((RSAKey) key).getModulus().toByteArray();
+        } else {
+            Log.w(TAG, "Not a RSAKey instance!");
+            return null;
+        }
+    }
+
+    /**
+     * Returns the 'Q' parameter of a given DSA private key as a byte
+     * buffer.
+     * This can be used by native code to convert it into an OpenSSL BIGNUM
+     * object where DSA_size() works as expected.
+     *
+     * @param key A PrivateKey instance. Must implement DSAKey.
+     * @return A byte buffer corresponding to the Q parameter. This is
+     * a big-endian representation of a BigInteger.
+     */
+    @CalledByNative
+    public static byte[] getDSAKeyParamQ(PrivateKey key) {
+        if (key instanceof DSAKey) {
+            DSAParams params = ((DSAKey) key).getParams();
+            return params.getQ().toByteArray();
+        } else {
+            Log.w(TAG, "Not a DSAKey instance!");
+            return null;
+        }
+    }
+
+    /**
+     * Returns the 'order' parameter of a given ECDSA private key as a
+     * a byte buffer.
+     * @param key A PrivateKey instance. Must implement ECKey.
+     * @return A byte buffer corresponding to the 'order' parameter.
+     * This is a big-endian representation of a BigInteger.
+     */
+    @CalledByNative
+    public static byte[] getECKeyOrder(PrivateKey key) {
+        if (key instanceof ECKey) {
+            ECParameterSpec params = ((ECKey) key).getParams();
+            return params.getOrder().toByteArray();
+        } else {
+            Log.w(TAG, "Not an ECKey instance!");
+            return null;
+        }
+    }
+
+    /**
+     * Returns the encoded data corresponding to a given PrivateKey.
+     * Note that this will fail for platform keys on Android 4.0.4
+     * and higher. It can be used on 4.0.3 and older platforms to
+     * route around the platform bug described below.
+     * @param key A PrivateKey instance
+     * @return encoded key as PKCS#8 byte array, can be null.
+     */
+    @CalledByNative
+    public static byte[] getPrivateKeyEncodedBytes(PrivateKey key) {
+        return key.getEncoded();
+    }
+
+    /**
+     * Called from native code to sign a given message with a given
+     * PrivateKey object for client certificate support.

[Ryan Sleevi, 2013/02/04 22:53:27]

These comments (for remaining native code) all have the style of describing how
the function *is used*, rather than how it *should be used*.

Similar to discussions on passive vs active voice (eg: why "we" is discouraged
in comments), these comments should provide clear guidance on the correct way to
use this, rather than try to describe how it's being used.

[digit1, 2013/02/05 14:31:58]

I've updated the comments so they could be a bit more direct.

+     *
+     * This method shall only be used to implement signing in the context
+     * of SSL client certificate support. More specifically, it will end
+     * up being called from OpenSSL itself through the custom EVP_PKEY
+     * wrapper defined in net/android/keystore_openssl.cc
+     *
+     * The message will actually be a hash, computed and padded by OpenSSL,
+     * itself, depending on the type of the key. The result should match
+     * exactly what the vanilla implementations of the following OpenSSL
+     * function calls do:
+     *
+     *  - For a RSA private key, this should be equivalent to calling
+     *    RSA_sign(NDI_md5_sha1,....), i.e. it must generate a pure RSA
+     *    signature. The message itself is 36-byte MD5+SHA1 message digest
+     *    with PKCS#1 padding.

[Ryan Sleevi, 2013/02/04 22:53:27]

comment nit: s/pure/raw/
comment nit:
The message itself must a combined, 36-byte MD5+SHA1 message digest padded to
the length of the modulus using PKCS#1 padding.

[digit1, 2013/02/05 14:31:58]

Done.

+     *
+     *  - For a DSA and ECDSA private keys, this should be equivalent to
+     *    calling DSA_sign(0,...) and ECDSA_sign(0,...) respectively. The
+     *    message will be a 20-byte SHA1 hash and the function shall
+     *    compute a direct DSA/ECDSA signature for it.

[Ryan Sleevi, 2013/02/04 22:53:27]

comment nit: s/will be/must be/

[digit1, 2013/02/05 14:31:58]

Done.

+     *
+     * @param privateKey The PrivateKey handle.
+     * @param message The message to sign.
+     * @return signature as a byte buffer.
+     *
+     * Important: Due to a platform bug, this function will always fail on
+     *            Android < 4.2 for RSA PrivateKey objects. See the
+     *            getOpenSSLHandleForPrivateKey() below for work-around.
+     */
+    @CalledByNative
+    public static byte[] rawSignDigestWithPrivateKey(PrivateKey privateKey,
+                                                     byte[] message) {
+        // Get the Signature for this key.
+        Signature signature = null;
+        // Hint: Algorithm names come from:
+        // http://docs.oracle.com/javase/6/docs/technotes/guides/security/StandardNames.html
+        try {
+            if (privateKey instanceof RSAPrivateKey) {
+                // IMPORTANT: Due to what looks like a platform bug, this will
+                // throw NoSuchAlgorithmException on Android 4.0.x and 4.1.x. Fixed in 4.2
+                // and higher. See https://android-review.googlesource.com/#/c/40352/

[Ryan Sleevi, 2013/02/04 22:53:27]

comment nit: This is no longer "what looks like", right? This is a confirmed
bug, with workaround (as seen on lines 138-140). Perhaps this should be removed?

[digit1, 2013/02/05 14:31:58]

Done.

+                signature = Signature.getInstance("NONEwithRSA");
+            } else if (privateKey instanceof DSAPrivateKey) {
+                signature = Signature.getInstance("NONEwithDSA");
+            } else if (privateKey instanceof ECPrivateKey) {
+                signature = Signature.getInstance("NONEwithECDSA");
+            }
+        } catch (NoSuchAlgorithmException e) {
+            ;
+        }
+
+        if (signature == null) {
+            Log.e(TAG, "Unsupported private key algorithm: " + privateKey.getAlgorithm());
+            return null;
+        }
+
+        // Sign the message.
+        try {
+            signature.initSign(privateKey);
+            signature.update(message);
+            return signature.sign();
+        } catch (Exception e) {
+            Log.e(TAG, "Exception while signing message with " + privateKey.getAlgorithm() +
+                        " private key: " + e);
+            return null;
+        }
+    }
+
+    /**
+     * Called from native code to return the type of a given PrivateKey
+     * object. This is an integer that maps to one of the values defined
+     * by org.chromium.net.PrivateKeyType, which is itself
+     * auto-generated from net/android/private_key_type_list.h
+     * @param privateKey The PrivateKey handle
+     * @return key type, or PrivateKeyType.INVALID if unknown.
+     */
+    @CalledByNative
+    public static int getPrivateKeyType(PrivateKey privateKey) {
+        if (privateKey instanceof RSAPrivateKey)
+            return PrivateKeyType.RSA;
+        if (privateKey instanceof DSAPrivateKey)
+            return PrivateKeyType.DSA;
+        if (privateKey instanceof ECPrivateKey)
+            return PrivateKeyType.ECDSA;
+        else
+            return PrivateKeyType.INVALID;
+    }
+
+    /**
+     * Called from native code to return the system EVP_PKEY handle
+     * corresponding to a given PrivateKey object, obtained through
+     * reflection (a.k.a. "Evil Hack 1").
+     *
+     * This shall only be used to work around the platform bug described
+     * above (namely that the "NONEwithRSA" signature is not available
+     * before Android 4.2).

[Ryan Sleevi, 2013/02/04 22:53:27]

comment nit: These sorts of positional references in comments make it hard to
move the code, or understand "how far above" to read.

perhaps a better way (of no doubt many):
"This is used for situations when "NONEwithRSA" signatures are unavailable, as
described in rawSignDigestWithPrivateKey"

[digit1, 2013/02/05 14:31:58]

Done.

+     *
+     * This can only work in Android 4.0.4 and higher, for older versions
+     * of the platform (e.g. 4.0.3), there is no system OpenSSL EVP_PKEY,
+     * but the private key contents can be retrieved directly with
+     * the getEncoded() method.
+     *
+     * This assumes that the target device uses a vanilla AOSP
+     * implementation of its java.security classes, which is also
+     * based on OpenSSL (fortunately, no OEM has apperently changed to
+     * a different implementation, according to the Android team).
+     *
+     * Note that the object returned was created with the platform version
+     * of OpenSSL, and _not_ the one that comes with Chromium. Whether the
+     * object can be used safely with the Chromium OpenSSL library depends
+     * on differences between their actual ABI / implementation details.
+     *
+     * To better understand what's going on below, please refer to the
+     * following source files in the Android 4.0.4 and 4.1 source trees:
+     * libcore/luni/src/main/java/org/apache/harmony/xnet/provider/jsse/OpenSSLRSAPrivateKey.java
+     * libcore/luni/src/main/native/org_apache_harmony_xnet_provider_jsse_NativeCrypto.cpp
+     *
+     * @param privateKey The PrivateKey handle.
+     * @return The EVP_PKEY handle, as a 32-bit integer (0 if not available)
+     */
+    @CalledByNative
+    public static int getOpenSSLHandleForPrivateKey(PrivateKey privateKey) {
+        // Sanity checks
+        if (privateKey == null) {
+            Log.e(TAG, "privateKey == null");
+            return 0;
+        }
+        if (!(privateKey instanceof RSAPrivateKey)) {
+            Log.e(TAG, "does not implement RSAPrivateKey");
+            return 0;
+        }
+        // First, check that this is a proper instance of OpenSSLRSAPrivateKey
+        // or one of its sub-classes.
+        Class<?> superClass;
+        try {
+            superClass = Class.forName(
+                    "org.apache.harmony.xnet.provider.jsse.OpenSSLRSAPrivateKey");
+        } catch (Exception e) {
+            // This may happen if the target device has a completely different
+            // implementation of the java.security APIs, compared to vanilla
+            // Android. Highly unlikely, but still possible.
+            Log.e(TAG, "Cannot find system OpenSSLRSAPrivateKey class: " + e);
+            return 0;
+        }
+        if (!superClass.isInstance(privateKey)) {
+            // This may happen if the PrivateKey was not created by the "AndroidOpenSSL"
+            // provider, which should be the default. That could happen if an OEM decided
+            // to implement a different default provider. Also highly unlikely.
+            Log.e(TAG, "Private key is not an OpenSSLRSAPrivateKey instance, its class name is:" +
+                       privateKey.getClass().getCanonicalName());
+            return 0;
+        }
+
+        try {
+            // Use reflection to invoke the 'getOpenSSLKey()' method on
+            // the private key. This returns another Java object that wraps
+            // a native EVP_PKEY. Note that the method is final, so calling
+            // the superclass implementation is ok.
+            Method getKey = superClass.getDeclaredMethod("getOpenSSLKey");
+            getKey.setAccessible(true);
+            Object opensslKey = null;
+            try {
+                opensslKey = getKey.invoke(privateKey);
+            } finally {
+                getKey.setAccessible(false);
+            }
+            if (opensslKey == null) {
+                // Bail when detecting OEM "enhancement".
+                Log.e(TAG, "getOpenSSLKey() returned null");
+                return 0;
+            }
+
+            // Use reflection to invoke the 'getPkeyContext' method on the
+            // result of the getOpenSSLKey(). This is an 32-bit integer
+            // which is the address of an EVP_PKEY object.
+            Method getPkeyContext;
+            try {
+                getPkeyContext = opensslKey.getClass().getDeclaredMethod("getPkeyContext");
+            } catch (Exception e) {
+                // Bail here too, something really not working as expected.
+                Log.e(TAG, "No getPkeyContext() method on OpenSSLKey member:" + e);
+                return 0;
+            }
+            getPkeyContext.setAccessible(true);
+            int evp_pkey = 0;
+            try {
+                evp_pkey = (Integer) getPkeyContext.invoke(opensslKey);
+            } finally {
+                getPkeyContext.setAccessible(false);
+            }
+            if (evp_pkey == 0) {
+                // The PrivateKey is probably rotten for some reason.
+                Log.e(TAG, "getPkeyContext() returned null");
+            }
+            return evp_pkey;
+
+        } catch (Exception e) {
+            Log.e(TAG, "Exception while trying to retrieve system EVP_PKEY handle: " + e);
+            return 0;
+        }
+    }
+}