Merge "Add CryptfsScryptHidlizationEquivalenceTest"

2 files changed, 499 insertions, 0 deletions

diff --git a/tests/Android.mk b/tests/Android.mk
index 416e6217..4b6573ea 100644
--- a/tests/Android.mk
+++ b/tests/Android.mk
@@ -8,8 +8,32 @@ LOCAL_C_INCLUDES := \
     system/core/fs_mgr/include
 
 LOCAL_STATIC_LIBRARIES := libselinux libvold liblog libcrypto
+
 LOCAL_SRC_FILES := VolumeManager_test.cpp
 LOCAL_MODULE := vold_tests
 LOCAL_MODULE_TAGS := eng tests
 
 include $(BUILD_NATIVE_TEST)
+
+include $(CLEAR_VARS)
+LOCAL_ADDITIONAL_DEPENDENCIES := $(LOCAL_PATH)/Android.mk
+
+# LOCAL_C_INCLUDES := \
+    system/core/fs_mgr/include
+
+LOCAL_STATIC_LIBRARIES := libselinux libvold liblog libcrypto
+LOCAL_SHARED_LIBRARIES := \
+    libutils \
+    libbase \
+    libhardware \
+    libhardware_legacy \
+    libhwbinder \
+    libhidlbase \
+    libkeystore_binder \
+    android.hardware.keymaster@3.0
+
+LOCAL_SRC_FILES := CryptfsScryptHidlizationEquivalence_test.cpp
+LOCAL_MODULE := vold_cryptfs_scrypt_hidlization_equivalence_test
+LOCAL_MODULE_TAGS := eng tests
+
+include $(BUILD_NATIVE_TEST)
diff --git a/tests/CryptfsScryptHidlizationEquivalence_test.cpp b/tests/CryptfsScryptHidlizationEquivalence_test.cpp
new file mode 100644
index 00000000..91ddb2ba
--- /dev/null
+++ b/tests/CryptfsScryptHidlizationEquivalence_test.cpp
@@ -0,0 +1,475 @@
+/*
+**
+** Copyright 2017, The Android Open Source Project
+**
+** Licensed under the Apache License, Version 2.0 (the "License");
+** you may not use this file except in compliance with the License.
+** You may obtain a copy of the License at
+**
+**     http://www.apache.org/licenses/LICENSE-2.0
+**
+** Unless required by applicable law or agreed to in writing, software
+** distributed under the License is distributed on an "AS IS" BASIS,
+** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+** See the License for the specific language governing permissions and
+** limitations under the License.
+*/
+
+#define LOG_TAG "scrypt_test"
+#include <log/log.h>
+
+#include <hardware/keymaster0.h>
+#include <hardware/keymaster1.h>
+#include <cstring>
+#include <gtest/gtest.h>
+
+#include "../cryptfs.h"
+#include "../Keymaster.h"
+
+#ifdef CONFIG_HW_DISK_ENCRYPTION
+#include "cryptfs_hw.h"
+#endif
+
+#define min(a, b) ((a) < (b) ? (a) : (b))
+
+/* Maximum allowed keymaster blob size. */
+#define KEYMASTER_BLOB_SIZE 2048
+
+/* Key Derivation Function algorithms */
+#define KDF_PBKDF2 1
+#define KDF_SCRYPT 2
+/* Algorithms 3 & 4 deprecated before shipping outside of google, so removed */
+#define KDF_SCRYPT_KEYMASTER 5
+
+#define KEY_LEN_BYTES 16
+
+#define DEFAULT_PASSWORD "default_password"
+
+#define RSA_KEY_SIZE 2048
+#define RSA_KEY_SIZE_BYTES (RSA_KEY_SIZE / 8)
+#define RSA_EXPONENT 0x10001
+#define KEYMASTER_CRYPTFS_RATE_LIMIT 1  // Maximum one try per second
+
+static int keymaster_init(keymaster0_device_t **keymaster0_dev,
+                          keymaster1_device_t **keymaster1_dev)
+{
+    int rc;
+
+    const hw_module_t* mod;
+    rc = hw_get_module_by_class(KEYSTORE_HARDWARE_MODULE_ID, NULL, &mod);
+    if (rc) {
+        ALOGE("could not find any keystore module");
+        goto err;
+    }
+
+    SLOGI("keymaster module name is %s", mod->name);
+    SLOGI("keymaster version is %d", mod->module_api_version);
+
+    *keymaster0_dev = NULL;
+    *keymaster1_dev = NULL;
+    if (mod->module_api_version == KEYMASTER_MODULE_API_VERSION_1_0) {
+        SLOGI("Found keymaster1 module, using keymaster1 API.");
+        rc = keymaster1_open(mod, keymaster1_dev);
+    } else {
+        SLOGI("Found keymaster0 module, using keymaster0 API.");
+        rc = keymaster0_open(mod, keymaster0_dev);
+    }
+
+    if (rc) {
+        ALOGE("could not open keymaster device in %s (%s)",
+              KEYSTORE_HARDWARE_MODULE_ID, strerror(-rc));
+        goto err;
+    }
+
+    return 0;
+
+err:
+    *keymaster0_dev = NULL;
+    *keymaster1_dev = NULL;
+    return rc;
+}
+
+/* Should we use keymaster? */
+static int keymaster_check_compatibility_old()
+{
+    keymaster0_device_t *keymaster0_dev = 0;
+    keymaster1_device_t *keymaster1_dev = 0;
+    int rc = 0;
+
+    if (keymaster_init(&keymaster0_dev, &keymaster1_dev)) {
+        SLOGE("Failed to init keymaster");
+        rc = -1;
+        goto out;
+    }
+
+    if (keymaster1_dev) {
+        rc = 1;
+        goto out;
+    }
+
+    if (!keymaster0_dev || !keymaster0_dev->common.module) {
+        rc = -1;
+        goto out;
+    }
+
+    // TODO(swillden): Check to see if there's any reason to require v0.3.  I think v0.1 and v0.2
+    // should work.
+    if (keymaster0_dev->common.module->module_api_version
+            < KEYMASTER_MODULE_API_VERSION_0_3) {
+        rc = 0;
+        goto out;
+    }
+
+    if (!(keymaster0_dev->flags & KEYMASTER_SOFTWARE_ONLY) &&
+        (keymaster0_dev->flags & KEYMASTER_BLOBS_ARE_STANDALONE)) {
+        rc = 1;
+    }
+
+out:
+    if (keymaster1_dev) {
+        keymaster1_close(keymaster1_dev);
+    }
+    if (keymaster0_dev) {
+        keymaster0_close(keymaster0_dev);
+    }
+    return rc;
+}
+
+/* Create a new keymaster key and store it in this footer */
+static int keymaster_create_key_old(struct crypt_mnt_ftr *ftr)
+{
+    uint8_t* key = 0;
+    keymaster0_device_t *keymaster0_dev = 0;
+    keymaster1_device_t *keymaster1_dev = 0;
+
+    if (ftr->keymaster_blob_size) {
+        SLOGI("Already have key");
+        return 0;
+    }
+
+    if (keymaster_init(&keymaster0_dev, &keymaster1_dev)) {
+        SLOGE("Failed to init keymaster");
+        return -1;
+    }
+
+    int rc = 0;
+    size_t key_size = 0;
+    if (keymaster1_dev) {
+        keymaster_key_param_t params[] = {
+            /* Algorithm & size specifications.  Stick with RSA for now.  Switch to AES later. */
+            keymaster_param_enum(KM_TAG_ALGORITHM, KM_ALGORITHM_RSA),
+            keymaster_param_int(KM_TAG_KEY_SIZE, RSA_KEY_SIZE),
+            keymaster_param_long(KM_TAG_RSA_PUBLIC_EXPONENT, RSA_EXPONENT),
+
+            /* The only allowed purpose for this key is signing. */
+            keymaster_param_enum(KM_TAG_PURPOSE, KM_PURPOSE_SIGN),
+
+            /* Padding & digest specifications. */
+            keymaster_param_enum(KM_TAG_PADDING, KM_PAD_NONE),
+            keymaster_param_enum(KM_TAG_DIGEST, KM_DIGEST_NONE),
+
+            /* Require that the key be usable in standalone mode.  File system isn't available. */
+            keymaster_param_enum(KM_TAG_BLOB_USAGE_REQUIREMENTS, KM_BLOB_STANDALONE),
+
+            /* No auth requirements, because cryptfs is not yet integrated with gatekeeper. */
+            keymaster_param_bool(KM_TAG_NO_AUTH_REQUIRED),
+
+            /* Rate-limit key usage attempts, to rate-limit brute force */
+            keymaster_param_int(KM_TAG_MIN_SECONDS_BETWEEN_OPS, KEYMASTER_CRYPTFS_RATE_LIMIT),
+        };
+        keymaster_key_param_set_t param_set = { params, sizeof(params)/sizeof(*params) };
+        keymaster_key_blob_t key_blob;
+        keymaster_error_t error = keymaster1_dev->generate_key(keymaster1_dev, &param_set,
+                                                               &key_blob,
+                                                               NULL /* characteristics */);
+        if (error != KM_ERROR_OK) {
+            SLOGE("Failed to generate keymaster1 key, error %d", error);
+            rc = -1;
+            goto out;
+        }
+
+        key = (uint8_t*)key_blob.key_material;
+        key_size = key_blob.key_material_size;
+    }
+    else if (keymaster0_dev) {
+        keymaster_rsa_keygen_params_t params;
+        memset(&params, '\0', sizeof(params));
+        params.public_exponent = RSA_EXPONENT;
+        params.modulus_size = RSA_KEY_SIZE;
+
+        if (keymaster0_dev->generate_keypair(keymaster0_dev, TYPE_RSA, &params,
+                                             &key, &key_size)) {
+            SLOGE("Failed to generate keypair");
+            rc = -1;
+            goto out;
+        }
+    } else {
+        SLOGE("Cryptfs bug: keymaster_init succeeded but didn't initialize a device");
+        rc = -1;
+        goto out;
+    }
+
+    if (key_size > KEYMASTER_BLOB_SIZE) {
+        SLOGE("Keymaster key too large for crypto footer");
+        rc = -1;
+        goto out;
+    }
+
+    memcpy(ftr->keymaster_blob, key, key_size);
+    ftr->keymaster_blob_size = key_size;
+
+out:
+    if (keymaster0_dev)
+        keymaster0_close(keymaster0_dev);
+    if (keymaster1_dev)
+        keymaster1_close(keymaster1_dev);
+    free(key);
+    return rc;
+}
+
+/* This signs the given object using the keymaster key. */
+static int keymaster_sign_object_old(struct crypt_mnt_ftr *ftr,
+                                 const unsigned char *object,
+                                 const size_t object_size,
+                                 unsigned char **signature,
+                                 size_t *signature_size)
+{
+    int rc = 0;
+    keymaster0_device_t *keymaster0_dev = 0;
+    keymaster1_device_t *keymaster1_dev = 0;
+
+    unsigned char to_sign[RSA_KEY_SIZE_BYTES];
+    size_t to_sign_size = sizeof(to_sign);
+    memset(to_sign, 0, RSA_KEY_SIZE_BYTES);
+
+    if (keymaster_init(&keymaster0_dev, &keymaster1_dev)) {
+        SLOGE("Failed to init keymaster");
+        rc = -1;
+        goto out;
+    }
+
+    // To sign a message with RSA, the message must satisfy two
+    // constraints:
+    //
+    // 1. The message, when interpreted as a big-endian numeric value, must
+    //    be strictly less than the public modulus of the RSA key.  Note
+    //    that because the most significant bit of the public modulus is
+    //    guaranteed to be 1 (else it's an (n-1)-bit key, not an n-bit
+    //    key), an n-bit message with most significant bit 0 always
+    //    satisfies this requirement.
+    //
+    // 2. The message must have the same length in bits as the public
+    //    modulus of the RSA key.  This requirement isn't mathematically
+    //    necessary, but is necessary to ensure consistency in
+    //    implementations.
+    switch (ftr->kdf_type) {
+        case KDF_SCRYPT_KEYMASTER:
+            // This ensures the most significant byte of the signed message
+            // is zero.  We could have zero-padded to the left instead, but
+            // this approach is slightly more robust against changes in
+            // object size.  However, it's still broken (but not unusably
+            // so) because we really should be using a proper deterministic
+            // RSA padding function, such as PKCS1.
+            memcpy(to_sign + 1, object, min(RSA_KEY_SIZE_BYTES - 1, object_size));
+            SLOGI("Signing safely-padded object");
+            break;
+        default:
+            SLOGE("Unknown KDF type %d", ftr->kdf_type);
+            rc = -1;
+            goto out;
+    }
+
+    if (keymaster0_dev) {
+        keymaster_rsa_sign_params_t params;
+        params.digest_type = DIGEST_NONE;
+        params.padding_type = PADDING_NONE;
+
+        rc = keymaster0_dev->sign_data(keymaster0_dev,
+                                      &params,
+                                      ftr->keymaster_blob,
+                                      ftr->keymaster_blob_size,
+                                      to_sign,
+                                      to_sign_size,
+                                      signature,
+                                      signature_size);
+        goto out;
+    } else if (keymaster1_dev) {
+        keymaster_key_blob_t key = { ftr->keymaster_blob, ftr->keymaster_blob_size };
+        keymaster_key_param_t params[] = {
+            keymaster_param_enum(KM_TAG_PADDING, KM_PAD_NONE),
+            keymaster_param_enum(KM_TAG_DIGEST, KM_DIGEST_NONE),
+        };
+        keymaster_key_param_set_t param_set = { params, sizeof(params)/sizeof(*params) };
+        keymaster_operation_handle_t op_handle;
+        keymaster_error_t error = keymaster1_dev->begin(keymaster1_dev, KM_PURPOSE_SIGN, &key,
+                                                        &param_set, NULL /* out_params */,
+                                                        &op_handle);
+        if (error == KM_ERROR_KEY_RATE_LIMIT_EXCEEDED) {
+            // Key usage has been rate-limited.  Wait a bit and try again.
+            sleep(KEYMASTER_CRYPTFS_RATE_LIMIT);
+            error = keymaster1_dev->begin(keymaster1_dev, KM_PURPOSE_SIGN, &key,
+                                          &param_set, NULL /* out_params */,
+                                          &op_handle);
+        }
+        if (error != KM_ERROR_OK) {
+            SLOGE("Error starting keymaster signature transaction: %d", error);
+            rc = -1;
+            goto out;
+        }
+
+        keymaster_blob_t input = { to_sign, to_sign_size };
+        size_t input_consumed;
+        error = keymaster1_dev->update(keymaster1_dev, op_handle, NULL /* in_params */,
+                                       &input, &input_consumed, NULL /* out_params */,
+                                       NULL /* output */);
+        if (error != KM_ERROR_OK) {
+            SLOGE("Error sending data to keymaster signature transaction: %d", error);
+            rc = -1;
+            goto out;
+        }
+        if (input_consumed != to_sign_size) {
+            // This should never happen.  If it does, it's a bug in the keymaster implementation.
+            SLOGE("Keymaster update() did not consume all data.");
+            keymaster1_dev->abort(keymaster1_dev, op_handle);
+            rc = -1;
+            goto out;
+        }
+
+        keymaster_blob_t tmp_sig;
+        error = keymaster1_dev->finish(keymaster1_dev, op_handle, NULL /* in_params */,
+                                       NULL /* verify signature */, NULL /* out_params */,
+                                       &tmp_sig);
+        if (error != KM_ERROR_OK) {
+            SLOGE("Error finishing keymaster signature transaction: %d", error);
+            rc = -1;
+            goto out;
+        }
+
+        *signature = (uint8_t*)tmp_sig.data;
+        *signature_size = tmp_sig.data_length;
+    } else {
+        SLOGE("Cryptfs bug: keymaster_init succeded but didn't initialize a device.");
+        rc = -1;
+        goto out;
+    }
+
+    out:
+        if (keymaster1_dev)
+            keymaster1_close(keymaster1_dev);
+        if (keymaster0_dev)
+            keymaster0_close(keymaster0_dev);
+
+        return rc;
+}
+
+
+/* Should we use keymaster? */
+static int keymaster_check_compatibility_new()
+{
+    return keymaster_compatibility_cryptfs_scrypt();
+}
+
+/* Create a new keymaster key and store it in this footer */
+static int keymaster_create_key_new(struct crypt_mnt_ftr *ftr)
+{
+    if (ftr->keymaster_blob_size) {
+        SLOGI("Already have key");
+        return 0;
+    }
+
+    int rc = keymaster_create_key_for_cryptfs_scrypt(RSA_KEY_SIZE, RSA_EXPONENT,
+            KEYMASTER_CRYPTFS_RATE_LIMIT, ftr->keymaster_blob, KEYMASTER_BLOB_SIZE,
+            &ftr->keymaster_blob_size);
+    if (rc) {
+        if (ftr->keymaster_blob_size > KEYMASTER_BLOB_SIZE) {
+            SLOGE("Keymaster key blob to large)");
+            ftr->keymaster_blob_size = 0;
+        }
+        SLOGE("Failed to generate keypair");
+        return -1;
+    }
+    return 0;
+}
+
+/* This signs the given object using the keymaster key. */
+static int keymaster_sign_object_new(struct crypt_mnt_ftr *ftr,
+                                 const unsigned char *object,
+                                 const size_t object_size,
+                                 unsigned char **signature,
+                                 size_t *signature_size)
+{
+    unsigned char to_sign[RSA_KEY_SIZE_BYTES];
+    size_t to_sign_size = sizeof(to_sign);
+    memset(to_sign, 0, RSA_KEY_SIZE_BYTES);
+
+    // To sign a message with RSA, the message must satisfy two
+    // constraints:
+    //
+    // 1. The message, when interpreted as a big-endian numeric value, must
+    //    be strictly less than the public modulus of the RSA key.  Note
+    //    that because the most significant bit of the public modulus is
+    //    guaranteed to be 1 (else it's an (n-1)-bit key, not an n-bit
+    //    key), an n-bit message with most significant bit 0 always
+    //    satisfies this requirement.
+    //
+    // 2. The message must have the same length in bits as the public
+    //    modulus of the RSA key.  This requirement isn't mathematically
+    //    necessary, but is necessary to ensure consistency in
+    //    implementations.
+    switch (ftr->kdf_type) {
+        case KDF_SCRYPT_KEYMASTER:
+            // This ensures the most significant byte of the signed message
+            // is zero.  We could have zero-padded to the left instead, but
+            // this approach is slightly more robust against changes in
+            // object size.  However, it's still broken (but not unusably
+            // so) because we really should be using a proper deterministic
+            // RSA padding function, such as PKCS1.
+            memcpy(to_sign + 1, object, min(RSA_KEY_SIZE_BYTES - 1, object_size));
+            SLOGI("Signing safely-padded object");
+            break;
+        default:
+            SLOGE("Unknown KDF type %d", ftr->kdf_type);
+            return -1;
+    }
+    return keymaster_sign_object_for_cryptfs_scrypt(ftr->keymaster_blob, ftr->keymaster_blob_size,
+            KEYMASTER_CRYPTFS_RATE_LIMIT, to_sign, to_sign_size, signature, signature_size);
+}
+
+namespace android {
+
+class CryptFsTest : public testing::Test {
+protected:
+    virtual void SetUp() {
+    }
+
+    virtual void TearDown() {
+    }
+};
+
+TEST_F(CryptFsTest, ScryptHidlizationEquivalenceTest) {
+    crypt_mnt_ftr ftr;
+    ftr.kdf_type = KDF_SCRYPT_KEYMASTER;
+    ftr.keymaster_blob_size = 0;
+
+    ASSERT_EQ(0, keymaster_create_key_old(&ftr));
+
+    uint8_t *sig1 = nullptr;
+    uint8_t *sig2 = nullptr;
+    size_t sig_size1 = 123456789;
+    size_t sig_size2 = 123456789;
+    uint8_t object[] = "the object";
+
+    ASSERT_EQ(1, keymaster_check_compatibility_old());
+    ASSERT_EQ(1, keymaster_check_compatibility_new());
+    ASSERT_EQ(0, keymaster_sign_object_old(&ftr, object, 10, &sig1, &sig_size1));
+    ASSERT_EQ(0, keymaster_sign_object_new(&ftr, object, 10, &sig2, &sig_size2));
+
+    ASSERT_EQ(sig_size1, sig_size2);
+    ASSERT_NE(nullptr, sig1);
+    ASSERT_NE(nullptr, sig2);
+    EXPECT_EQ(0, memcmp(sig1, sig2, sig_size1));
+    free(sig1);
+    free(sig2);
+}
+
+}