diff options
| -rw-r--r-- | keystore/java/android/security/keystore/AndroidKeyStoreCipherSpiBase.java | 15 | ||||
| -rw-r--r-- | keystore/java/android/security/keystore/AndroidKeyStoreRSACipherSpi.java | 69 |
2 files changed, 66 insertions, 18 deletions
diff --git a/keystore/java/android/security/keystore/AndroidKeyStoreCipherSpiBase.java b/keystore/java/android/security/keystore/AndroidKeyStoreCipherSpiBase.java index 50f3ed4..38cacd0 100644 --- a/keystore/java/android/security/keystore/AndroidKeyStoreCipherSpiBase.java +++ b/keystore/java/android/security/keystore/AndroidKeyStoreCipherSpiBase.java @@ -731,6 +731,21 @@ abstract class AndroidKeyStoreCipherSpiBase extends CipherSpi implements KeyStor return mMainDataStreamer.getProducedOutputSizeBytes(); } + static String opmodeToString(int opmode) { + switch (opmode) { + case Cipher.ENCRYPT_MODE: + return "ENCRYPT_MODE"; + case Cipher.DECRYPT_MODE: + return "DECRYPT_MODE"; + case Cipher.WRAP_MODE: + return "WRAP_MODE"; + case Cipher.UNWRAP_MODE: + return "UNWRAP_MODE"; + default: + return String.valueOf(opmode); + } + } + // The methods below need to be implemented by subclasses. /** diff --git a/keystore/java/android/security/keystore/AndroidKeyStoreRSACipherSpi.java b/keystore/java/android/security/keystore/AndroidKeyStoreRSACipherSpi.java index 8e58195..94ed8b4 100644 --- a/keystore/java/android/security/keystore/AndroidKeyStoreRSACipherSpi.java +++ b/keystore/java/android/security/keystore/AndroidKeyStoreRSACipherSpi.java @@ -60,9 +60,10 @@ abstract class AndroidKeyStoreRSACipherSpi extends AndroidKeyStoreCipherSpiBase } @Override - protected boolean isEncryptingUsingPrivateKeyPermitted() { - // RSA encryption with no padding using private key is is a way to implement raw RSA - // signatures. We have to support this. + protected boolean adjustConfigForEncryptingWithPrivateKey() { + // RSA encryption with no padding using private key is a way to implement raw RSA + // signatures which JCA does not expose via Signature. We thus have to support this. + setKeymasterPurposeOverride(KeymasterDefs.KM_PURPOSE_SIGN); return true; } @@ -198,6 +199,15 @@ abstract class AndroidKeyStoreRSACipherSpi extends AndroidKeyStoreCipherSpiBase } @Override + protected boolean adjustConfigForEncryptingWithPrivateKey() { + // RSA encryption with PCKS#1 padding using private key is a way to implement RSA + // signatures with PKCS#1 padding. We have to support this for legacy reasons. + setKeymasterPurposeOverride(KeymasterDefs.KM_PURPOSE_SIGN); + setKeymasterPaddingOverride(KeymasterDefs.KM_PAD_RSA_PKCS1_1_5_SIGN); + return true; + } + + @Override protected void initAlgorithmSpecificParameters() throws InvalidKeyException {} @Override @@ -425,6 +435,7 @@ abstract class AndroidKeyStoreRSACipherSpi extends AndroidKeyStoreCipherSpiBase } private final int mKeymasterPadding; + private int mKeymasterPaddingOverride; private int mModulusSizeBytes = -1; @@ -458,20 +469,15 @@ abstract class AndroidKeyStoreRSACipherSpi extends AndroidKeyStoreCipherSpiBase // Permitted break; case Cipher.ENCRYPT_MODE: - if (!isEncryptingUsingPrivateKeyPermitted()) { + case Cipher.WRAP_MODE: + if (!adjustConfigForEncryptingWithPrivateKey()) { throw new InvalidKeyException( - "RSA private keys cannot be used with Cipher.ENCRYPT_MODE" + "RSA private keys cannot be used with " + opmodeToString(opmode) + + " and padding " + + KeyProperties.EncryptionPadding.fromKeymaster(mKeymasterPadding) + ". Only RSA public keys supported for this mode"); } - // JCA doesn't provide a way to generate raw RSA signatures (with arbitrary - // padding). Thus, encrypting with private key is used instead. - setKeymasterPurposeOverride(KeymasterDefs.KM_PURPOSE_SIGN); break; - case Cipher.WRAP_MODE: - throw new InvalidKeyException( - "RSA private keys cannot be used with Cipher.WRAP_MODE" - + ". Only RSA public keys supported for this mode"); - // break; default: throw new InvalidKeyException( "RSA private keys cannot be used with opmode: " + opmode); @@ -485,12 +491,15 @@ abstract class AndroidKeyStoreRSACipherSpi extends AndroidKeyStoreCipherSpiBase break; case Cipher.DECRYPT_MODE: case Cipher.UNWRAP_MODE: - throw new InvalidKeyException("RSA public keys cannot be used with opmode: " - + opmode + ". Only RSA private keys supported for this opmode."); + throw new InvalidKeyException( + "RSA public keys cannot be used with " + opmodeToString(opmode) + + " and padding " + + KeyProperties.EncryptionPadding.fromKeymaster(mKeymasterPadding) + + ". Only RSA private keys supported for this opmode."); // break; default: throw new InvalidKeyException( - "RSA public keys cannot be used with opmode: " + opmode); + "RSA public keys cannot be used with " + opmodeToString(opmode)); } } @@ -511,13 +520,22 @@ abstract class AndroidKeyStoreRSACipherSpi extends AndroidKeyStoreCipherSpiBase setKey(keystoreKey); } - protected boolean isEncryptingUsingPrivateKeyPermitted() { + /** + * Adjusts the configuration of this cipher for encrypting using the private key. + * + * <p>The default implementation does nothing and refuses to adjust the configuration. + * + * @return {@code true} if the configuration has been adjusted, {@code false} if encrypting + * using private key is not permitted for this cipher. + */ + protected boolean adjustConfigForEncryptingWithPrivateKey() { return false; } @Override protected final void resetAll() { mModulusSizeBytes = -1; + mKeymasterPaddingOverride = -1; super.resetAll(); } @@ -530,7 +548,11 @@ abstract class AndroidKeyStoreRSACipherSpi extends AndroidKeyStoreCipherSpiBase protected void addAlgorithmSpecificParametersToBegin( @NonNull KeymasterArguments keymasterArgs) { keymasterArgs.addEnum(KeymasterDefs.KM_TAG_ALGORITHM, KeymasterDefs.KM_ALGORITHM_RSA); - keymasterArgs.addEnum(KeymasterDefs.KM_TAG_PADDING, mKeymasterPadding); + int keymasterPadding = getKeymasterPaddingOverride(); + if (keymasterPadding == -1) { + keymasterPadding = mKeymasterPadding; + } + keymasterArgs.addEnum(KeymasterDefs.KM_TAG_PADDING, keymasterPadding); int purposeOverride = getKeymasterPurposeOverride(); if ((purposeOverride != -1) && ((purposeOverride == KeymasterDefs.KM_PURPOSE_SIGN) @@ -568,4 +590,15 @@ abstract class AndroidKeyStoreRSACipherSpi extends AndroidKeyStoreCipherSpiBase } return mModulusSizeBytes; } + + /** + * Overrides the default padding of the crypto operation. + */ + protected final void setKeymasterPaddingOverride(int keymasterPadding) { + mKeymasterPaddingOverride = keymasterPadding; + } + + protected final int getKeymasterPaddingOverride() { + return mKeymasterPaddingOverride; + } } |