1 files changed, 239 insertions, 0 deletions
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/CanonicalizedSecretKey.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/CanonicalizedSecretKey.java
new file mode 100644
index 000000000..ff82da07a
--- /dev/null
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/CanonicalizedSecretKey.java
@@ -0,0 +1,239 @@
+package org.sufficientlysecure.keychain.pgp;
+
+import org.spongycastle.bcpg.HashAlgorithmTags;
+import org.spongycastle.bcpg.S2K;
+import org.spongycastle.openpgp.PGPException;
+import org.spongycastle.openpgp.PGPPrivateKey;
+import org.spongycastle.openpgp.PGPPublicKey;
+import org.spongycastle.openpgp.PGPPublicKeyRing;
+import org.spongycastle.openpgp.PGPSecretKey;
+import org.spongycastle.openpgp.PGPSignature;
+import org.spongycastle.openpgp.PGPSignatureGenerator;
+import org.spongycastle.openpgp.PGPSignatureSubpacketGenerator;
+import org.spongycastle.openpgp.PGPSignatureSubpacketVector;
+import org.spongycastle.openpgp.PGPUtil;
+import org.spongycastle.openpgp.operator.PBESecretKeyDecryptor;
+import org.spongycastle.openpgp.operator.PGPContentSignerBuilder;
+import org.spongycastle.openpgp.operator.PublicKeyDataDecryptorFactory;
+import org.spongycastle.openpgp.operator.jcajce.JcaPGPContentSignerBuilder;
+import org.spongycastle.openpgp.operator.jcajce.JcePBESecretKeyDecryptorBuilder;
+import org.spongycastle.openpgp.operator.jcajce.JcePublicKeyDataDecryptorFactoryBuilder;
+import org.spongycastle.openpgp.operator.jcajce.NfcSyncPGPContentSignerBuilder;
+import org.sufficientlysecure.keychain.Constants;
+import org.sufficientlysecure.keychain.pgp.exception.PgpGeneralException;
+import org.sufficientlysecure.keychain.pgp.exception.PgpGeneralMsgIdException;
+import org.sufficientlysecure.keychain.util.IterableIterator;
+import org.sufficientlysecure.keychain.util.Log;
+
+import java.security.NoSuchAlgorithmException;
+import java.security.NoSuchProviderException;
+import java.security.SignatureException;
+import java.util.Date;
+import java.util.LinkedList;
+import java.util.List;
+
+/** Wrapper for a PGPSecretKey.
+ *
+ * This object can only be obtained from a WrappedSecretKeyRing, and stores a
+ * back reference to its parent.
+ *
+ * This class represents known secret keys which are stored in the database.
+ * All "crypto operations using a known secret key" should be implemented in
+ * this class, to ensure on type level that these operations are performed on
+ * properly imported secret keys only.
+ *
+ */
+public class CanonicalizedSecretKey extends CanonicalizedPublicKey {
+
+    private final PGPSecretKey mSecretKey;
+    private PGPPrivateKey mPrivateKey = null;
+
+    private int mPrivateKeyState = PRIVATE_KEY_STATE_LOCKED;
+    private static int PRIVATE_KEY_STATE_LOCKED = 0;
+    private static int PRIVATE_KEY_STATE_UNLOCKED = 1;
+    private static int PRIVATE_KEY_STATE_DIVERT_TO_CARD = 2;
+
+    CanonicalizedSecretKey(CanonicalizedSecretKeyRing ring, PGPSecretKey key) {
+        super(ring, key.getPublicKey());
+        mSecretKey = key;
+    }
+
+    public CanonicalizedSecretKeyRing getRing() {
+        return (CanonicalizedSecretKeyRing) mRing;
+    }
+
+    /**
+     * Returns true on right passphrase
+     */
+    public boolean unlock(String passphrase) throws PgpGeneralException {
+        // handle keys on OpenPGP cards like they were unlocked
+        if (mSecretKey.getS2K().getType() == S2K.GNU_DUMMY_S2K
+                && mSecretKey.getS2K().getProtectionMode() == S2K.GNU_PROTECTION_MODE_DIVERT_TO_CARD) {
+            mPrivateKeyState = PRIVATE_KEY_STATE_DIVERT_TO_CARD;
+            return true;
+        }
+
+        // try to extract keys using the passphrase
+        try {
+            PBESecretKeyDecryptor keyDecryptor = new JcePBESecretKeyDecryptorBuilder().setProvider(
+                    Constants.BOUNCY_CASTLE_PROVIDER_NAME).build(passphrase.toCharArray());
+            mPrivateKey = mSecretKey.extractPrivateKey(keyDecryptor);
+            mPrivateKeyState = PRIVATE_KEY_STATE_UNLOCKED;
+        } catch (PGPException e) {
+            return false;
+        }
+        if(mPrivateKey == null) {
+            throw new PgpGeneralException("error extracting key");
+        }
+        return true;
+    }
+
+    // TODO: just a hack currently
+    public LinkedList<Integer> getSupportedHashAlgorithms() {
+        LinkedList<Integer> supported = new LinkedList<Integer>();
+
+        if (mPrivateKeyState == PRIVATE_KEY_STATE_DIVERT_TO_CARD) {
+            // TODO: only works with SHA256 ?!
+            supported.add(HashAlgorithmTags.SHA256);
+        } else {
+            supported.add(HashAlgorithmTags.MD5);
+            supported.add(HashAlgorithmTags.RIPEMD160);
+            supported.add(HashAlgorithmTags.SHA1);
+            supported.add(HashAlgorithmTags.SHA224);
+            supported.add(HashAlgorithmTags.SHA256);
+            supported.add(HashAlgorithmTags.SHA384);
+            supported.add(HashAlgorithmTags.SHA512); // preferred is latest
+        }
+
+        return supported;
+    }
+
+    public PGPSignatureGenerator getSignatureGenerator(int hashAlgo, boolean cleartext,
+                                                       byte[] nfcSignedHash, Date nfcCreationTimestamp)
+            throws PgpGeneralException {
+        if (mPrivateKeyState == PRIVATE_KEY_STATE_LOCKED) {
+            throw new PrivateKeyNotUnlockedException();
+        }
+
+        PGPContentSignerBuilder contentSignerBuilder;
+        if (mPrivateKeyState == PRIVATE_KEY_STATE_DIVERT_TO_CARD) {
+            // to sign using nfc PgpSignEncrypt is executed two times.
+            // the first time it stops to return the PendingIntent for nfc connection and signing the hash
+            // the second time the signed hash is used.
+            // to get the same hash we cache the timestamp for the second round!
+            if (nfcCreationTimestamp == null) {
+                nfcCreationTimestamp = new Date();
+            }
+
+            // use synchronous "NFC based" SignerBuilder
+            contentSignerBuilder = new NfcSyncPGPContentSignerBuilder(
+                    mSecretKey.getPublicKey().getAlgorithm(), hashAlgo,
+                    mSecretKey.getKeyID(), nfcSignedHash, nfcCreationTimestamp)
+                    .setProvider(Constants.BOUNCY_CASTLE_PROVIDER_NAME);
+
+            Log.d(Constants.TAG, "mSecretKey.getKeyID() "+ PgpKeyHelper.convertKeyIdToHex(mSecretKey.getKeyID()));
+        } else {
+            // content signer based on signing key algorithm and chosen hash algorithm
+            contentSignerBuilder = new JcaPGPContentSignerBuilder(
+                    mSecretKey.getPublicKey().getAlgorithm(), hashAlgo)
+                    .setProvider(Constants.BOUNCY_CASTLE_PROVIDER_NAME);
+        }
+
+        int signatureType;
+        if (cleartext) {
+            // for sign-only ascii text
+            signatureType = PGPSignature.CANONICAL_TEXT_DOCUMENT;
+        } else {
+            signatureType = PGPSignature.BINARY_DOCUMENT;
+        }
+
+        try {
+            PGPSignatureGenerator signatureGenerator = new PGPSignatureGenerator(contentSignerBuilder);
+            signatureGenerator.init(signatureType, mPrivateKey);
+
+            PGPSignatureSubpacketGenerator spGen = new PGPSignatureSubpacketGenerator();
+            spGen.setSignerUserID(false, mRing.getPrimaryUserIdWithFallback());
+            if (nfcCreationTimestamp != null) {
+                spGen.setSignatureCreationTime(false, nfcCreationTimestamp);
+                Log.d(Constants.TAG, "For NFC: set sig creation time to " + nfcCreationTimestamp);
+            }
+            signatureGenerator.setHashedSubpackets(spGen.generate());
+            return signatureGenerator;
+        } catch(PGPException e) {
+            // TODO: simply throw PGPException!
+            throw new PgpGeneralException("Error initializing signature!", e);
+        }
+    }
+
+    public PublicKeyDataDecryptorFactory getDecryptorFactory() {
+        // TODO: divert to card missing
+        if (mPrivateKeyState != PRIVATE_KEY_STATE_UNLOCKED) {
+            throw new PrivateKeyNotUnlockedException();
+        }
+        return new JcePublicKeyDataDecryptorFactoryBuilder()
+                .setProvider(Constants.BOUNCY_CASTLE_PROVIDER_NAME).build(mPrivateKey);
+    }
+
+    /**
+     * Certify the given pubkeyid with the given masterkeyid.
+     *
+     * @param publicKeyRing    Keyring to add certification to.
+     * @param userIds          User IDs to certify, must not be null or empty
+     * @return A keyring with added certifications
+     */
+    public UncachedKeyRing certifyUserIds(CanonicalizedPublicKeyRing publicKeyRing, List<String> userIds)
+            throws PgpGeneralMsgIdException, NoSuchAlgorithmException, NoSuchProviderException,
+            PGPException, SignatureException {
+
+        // TODO: divert to card missing
+        if (mPrivateKeyState != PRIVATE_KEY_STATE_UNLOCKED) {
+            throw new PrivateKeyNotUnlockedException();
+        }
+
+        // create a signatureGenerator from the supplied masterKeyId and passphrase
+        PGPSignatureGenerator signatureGenerator;
+        {
+            // TODO: SHA256 fixed?
+            JcaPGPContentSignerBuilder contentSignerBuilder = new JcaPGPContentSignerBuilder(
+                    mSecretKey.getPublicKey().getAlgorithm(), PGPUtil.SHA256)
+                    .setProvider(Constants.BOUNCY_CASTLE_PROVIDER_NAME);
+
+            signatureGenerator = new PGPSignatureGenerator(contentSignerBuilder);
+            signatureGenerator.init(PGPSignature.DEFAULT_CERTIFICATION, mPrivateKey);
+        }
+
+        { // supply signatureGenerator with a SubpacketVector
+            PGPSignatureSubpacketGenerator spGen = new PGPSignatureSubpacketGenerator();
+            PGPSignatureSubpacketVector packetVector = spGen.generate();
+            signatureGenerator.setHashedSubpackets(packetVector);
+        }
+
+        // get the master subkey (which we certify for)
+        PGPPublicKey publicKey = publicKeyRing.getPublicKey().getPublicKey();
+
+        // fetch public key ring, add the certification and return it
+        for (String userId : new IterableIterator<String>(userIds.iterator())) {
+            PGPSignature sig = signatureGenerator.generateCertification(userId, publicKey);
+            publicKey = PGPPublicKey.addCertification(publicKey, userId, sig);
+        }
+
+        PGPPublicKeyRing ring = PGPPublicKeyRing.insertPublicKey(publicKeyRing.getRing(), publicKey);
+
+        return new UncachedKeyRing(ring);
+    }
+
+    static class PrivateKeyNotUnlockedException extends RuntimeException {
+        // this exception is a programming error which happens when an operation which requires
+        // the private key is called without a previous call to unlock()
+    }
+
+    public UncachedSecretKey getUncached() {
+        return new UncachedSecretKey(mSecretKey);
+    }
+
+    // HACK
+    public PGPSecretKey getSecretKey() {
+        return mSecretKey;
+    }
+
+}