HACK: Import gatekeeper from goldfish

Instead, there might be a way to make the default GateKeeper
implementation fall back on its internal software implementation
on which the goldfish implementation is based as it has the
following code:
  hw_device = IGatekeeper::getService();

  if (hw_device == nullptr) {
    ALOGW("falling back to software GateKeeper");
    soft_device.reset(new SoftGateKeeperDevice());
  }

The implementation has been imported from the lineage-16.0 branch of
the https://github.com/LineageOS/android_device_generic_goldfish
repository at the following commit:
  b05b939 Snap for 5130385 from eabd93d25de5a95d6544822d62af6744176fd5e6 to pi-qpr2-release

Only the module name and device name have been changed by:
* using sed 's#goldfish#i9305#g' -i gatekeeper/*
* using sed 's#gatekeeper.ranchu#gatekeeper.default.so#g' -i gatekeeper/Android.mk
* correcting gatekeeper module name
* changing gatekeeper_module.name and LOG_TAG from goldfish to I9305

Signed-off-by: Denis 'GNUtoo' Carikli <GNUtoo@cyberdimension.org>

6 files changed, 549 insertions, 0 deletions

diff --git a/device.mk b/device.mk
index 599b69e..028854c 100644
--- a/device.mk
+++ b/device.mk
@@ -113,3 +113,6 @@ endif
 PRODUCT_PROPERTY_OVERRIDES += \
     persist.service.adb.enable=1 \
     persist.sys.usb.config=adb
+
+# Hack to get a working GateKeeper
+PRODUCT_PACKAGES += gatekeeper.default
diff --git a/gatekeeper/Android.mk b/gatekeeper/Android.mk
new file mode 100644
index 0000000..823bd2b
--- /dev/null
+++ b/gatekeeper/Android.mk
@@ -0,0 +1,45 @@
+#
+# Copyright (C) 2015 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.
+#
+
+LOCAL_PATH := $(call my-dir)
+
+include $(CLEAR_VARS)
+LOCAL_VENDOR_MODULE := true
+LOCAL_MODULE := gatekeeper.default
+LOCAL_MODULE_RELATIVE_PATH := hw
+
+LOCAL_CFLAGS := -Wall -Wextra -Werror -Wunused
+LOCAL_SRC_FILES := \
+	module.cpp \
+	SoftGateKeeperDevice.cpp
+
+
+LOCAL_SHARED_LIBRARIES := \
+	libbinder \
+	libgatekeeper \
+	liblog \
+	libhardware \
+	libbase \
+	libutils \
+	libcrypto \
+	libhidlbase \
+	libhidltransport \
+	libhwbinder \
+	android.hardware.gatekeeper@1.0 \
+
+LOCAL_STATIC_LIBRARIES := libscrypt_static
+LOCAL_C_INCLUDES := external/scrypt/lib/crypto
+include $(BUILD_SHARED_LIBRARY)
diff --git a/gatekeeper/SoftGateKeeper.h b/gatekeeper/SoftGateKeeper.h
new file mode 100644
index 0000000..2f4f4d7
--- /dev/null
+++ b/gatekeeper/SoftGateKeeper.h
@@ -0,0 +1,182 @@
+/*
+ * Copyright 2015 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.
+ *
+ */
+
+#ifndef SOFT_GATEKEEPER_H_
+#define SOFT_GATEKEEPER_H_
+
+extern "C" {
+#include <openssl/rand.h>
+#include <openssl/sha.h>
+
+#include <crypto_scrypt.h>
+}
+
+#include <android-base/memory.h>
+#include <gatekeeper/gatekeeper.h>
+
+#include <iostream>
+#include <unordered_map>
+#include <memory>
+
+namespace gatekeeper {
+
+struct fast_hash_t {
+    uint64_t salt;
+    uint8_t digest[SHA256_DIGEST_LENGTH];
+};
+
+class SoftGateKeeper : public GateKeeper {
+public:
+    static const uint32_t SIGNATURE_LENGTH_BYTES = 32;
+
+    // scrypt params
+    static const uint64_t N = 16384;
+    static const uint32_t r = 8;
+    static const uint32_t p = 1;
+
+    static const int MAX_UINT_32_CHARS = 11;
+
+    SoftGateKeeper() {
+        key_.reset(new uint8_t[SIGNATURE_LENGTH_BYTES]);
+        memset(key_.get(), 0, SIGNATURE_LENGTH_BYTES);
+    }
+
+    virtual ~SoftGateKeeper() {
+    }
+
+    virtual bool GetAuthTokenKey(const uint8_t **auth_token_key,
+            uint32_t *length) const {
+        if (auth_token_key == NULL || length == NULL) return false;
+        uint8_t *auth_token_key_copy = new uint8_t[SIGNATURE_LENGTH_BYTES];
+        memcpy(auth_token_key_copy, key_.get(), SIGNATURE_LENGTH_BYTES);
+
+        *auth_token_key = auth_token_key_copy;
+        *length = SIGNATURE_LENGTH_BYTES;
+        return true;
+    }
+
+    virtual void GetPasswordKey(const uint8_t **password_key, uint32_t *length) {
+        if (password_key == NULL || length == NULL) return;
+        uint8_t *password_key_copy = new uint8_t[SIGNATURE_LENGTH_BYTES];
+        memcpy(password_key_copy, key_.get(), SIGNATURE_LENGTH_BYTES);
+
+        *password_key = password_key_copy;
+        *length = SIGNATURE_LENGTH_BYTES;
+    }
+
+    virtual void ComputePasswordSignature(uint8_t *signature, uint32_t signature_length,
+            const uint8_t *, uint32_t, const uint8_t *password,
+            uint32_t password_length, salt_t salt) const {
+        if (signature == NULL) return;
+        crypto_scrypt(password, password_length, reinterpret_cast<uint8_t *>(&salt),
+                sizeof(salt), N, r, p, signature, signature_length);
+    }
+
+    virtual void GetRandom(void *random, uint32_t requested_length) const {
+        if (random == NULL) return;
+        RAND_pseudo_bytes((uint8_t *) random, requested_length);
+    }
+
+    virtual void ComputeSignature(uint8_t *signature, uint32_t signature_length,
+            const uint8_t *, uint32_t, const uint8_t *, const uint32_t) const {
+        if (signature == NULL) return;
+        memset(signature, 0, signature_length);
+    }
+
+    virtual uint64_t GetMillisecondsSinceBoot() const {
+        struct timespec time;
+        int res = clock_gettime(CLOCK_BOOTTIME, &time);
+        if (res < 0) return 0;
+        return (time.tv_sec * 1000) + (time.tv_nsec / 1000 / 1000);
+    }
+
+    virtual bool IsHardwareBacked() const {
+        return false;
+    }
+
+    virtual bool GetFailureRecord(uint32_t uid, secure_id_t user_id, failure_record_t *record,
+            bool /* secure */) {
+        failure_record_t *stored = &failure_map_[uid];
+        if (user_id != stored->secure_user_id) {
+            stored->secure_user_id = user_id;
+            stored->last_checked_timestamp = 0;
+            stored->failure_counter = 0;
+        }
+        memcpy(record, stored, sizeof(*record));
+        return true;
+    }
+
+    virtual bool ClearFailureRecord(uint32_t uid, secure_id_t user_id, bool /* secure */) {
+        failure_record_t *stored = &failure_map_[uid];
+        stored->secure_user_id = user_id;
+        stored->last_checked_timestamp = 0;
+        stored->failure_counter = 0;
+        return true;
+    }
+
+    virtual bool WriteFailureRecord(uint32_t uid, failure_record_t *record, bool /* secure */) {
+        failure_map_[uid] = *record;
+        return true;
+    }
+
+    fast_hash_t ComputeFastHash(const SizedBuffer &password, uint64_t salt) {
+        fast_hash_t fast_hash;
+        size_t digest_size = password.length + sizeof(salt);
+        std::unique_ptr<uint8_t[]> digest(new uint8_t[digest_size]);
+        memcpy(digest.get(), &salt, sizeof(salt));
+        memcpy(digest.get() + sizeof(salt), password.buffer.get(), password.length);
+
+        SHA256(digest.get(), digest_size, (uint8_t *) &fast_hash.digest);
+
+        fast_hash.salt = salt;
+        return fast_hash;
+    }
+
+    bool VerifyFast(const fast_hash_t &fast_hash, const SizedBuffer &password) {
+        fast_hash_t computed = ComputeFastHash(password, fast_hash.salt);
+        return memcmp(computed.digest, fast_hash.digest, SHA256_DIGEST_LENGTH) == 0;
+    }
+
+    bool DoVerify(const password_handle_t *expected_handle, const SizedBuffer &password) {
+        uint64_t user_id = android::base::get_unaligned<secure_id_t>(&expected_handle->user_id);
+        FastHashMap::const_iterator it = fast_hash_map_.find(user_id);
+        if (it != fast_hash_map_.end() && VerifyFast(it->second, password)) {
+            return true;
+        } else {
+            if (GateKeeper::DoVerify(expected_handle, password)) {
+                uint64_t salt;
+                GetRandom(&salt, sizeof(salt));
+                fast_hash_map_[user_id] = ComputeFastHash(password, salt);
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+private:
+
+    typedef std::unordered_map<uint32_t, failure_record_t> FailureRecordMap;
+    typedef std::unordered_map<uint64_t, fast_hash_t> FastHashMap;
+
+    std::unique_ptr<uint8_t[]> key_;
+    FailureRecordMap failure_map_;
+    FastHashMap fast_hash_map_;
+};
+}
+
+#endif // SOFT_GATEKEEPER_H_
diff --git a/gatekeeper/SoftGateKeeperDevice.cpp b/gatekeeper/SoftGateKeeperDevice.cpp
new file mode 100644
index 0000000..a504fba
--- /dev/null
+++ b/gatekeeper/SoftGateKeeperDevice.cpp
@@ -0,0 +1,116 @@
+/*
+ * Copyright (C) 2015 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.
+ */
+#include "SoftGateKeeper.h"
+#include "SoftGateKeeperDevice.h"
+
+namespace i9305 {
+
+int SoftGateKeeperDevice::enroll(uint32_t uid,
+            const uint8_t *current_password_handle, uint32_t current_password_handle_length,
+            const uint8_t *current_password, uint32_t current_password_length,
+            const uint8_t *desired_password, uint32_t desired_password_length,
+            uint8_t **enrolled_password_handle, uint32_t *enrolled_password_handle_length) {
+
+    if (enrolled_password_handle == NULL || enrolled_password_handle_length == NULL ||
+            desired_password == NULL || desired_password_length == 0)
+        return -EINVAL;
+
+    // Current password and current password handle go together
+    if (current_password_handle == NULL || current_password_handle_length == 0 ||
+            current_password == NULL || current_password_length == 0) {
+        current_password_handle = NULL;
+        current_password_handle_length = 0;
+        current_password = NULL;
+        current_password_length = 0;
+    }
+
+    SizedBuffer desired_password_buffer(desired_password_length);
+    memcpy(desired_password_buffer.buffer.get(), desired_password, desired_password_length);
+
+    SizedBuffer current_password_handle_buffer(current_password_handle_length);
+    if (current_password_handle) {
+        memcpy(current_password_handle_buffer.buffer.get(), current_password_handle,
+                current_password_handle_length);
+    }
+
+    SizedBuffer current_password_buffer(current_password_length);
+    if (current_password) {
+        memcpy(current_password_buffer.buffer.get(), current_password, current_password_length);
+    }
+
+    EnrollRequest request(uid, &current_password_handle_buffer, &desired_password_buffer,
+            &current_password_buffer);
+    EnrollResponse response;
+
+    impl_->Enroll(request, &response);
+
+    if (response.error == ERROR_RETRY) {
+        return response.retry_timeout;
+    } else if (response.error != ERROR_NONE) {
+        return -EINVAL;
+    }
+
+    *enrolled_password_handle = response.enrolled_password_handle.buffer.release();
+    gatekeeper::password_handle_t *handle =
+                    reinterpret_cast<gatekeeper::password_handle_t *>(*enrolled_password_handle);
+    //FIXIT: We need to move this module to host with gatekeeper pipe
+    handle->hardware_backed = true;
+
+    *enrolled_password_handle_length = response.enrolled_password_handle.length;
+    return 0;
+}
+
+int SoftGateKeeperDevice::verify(uint32_t uid,
+        uint64_t challenge, const uint8_t *enrolled_password_handle,
+        uint32_t enrolled_password_handle_length, const uint8_t *provided_password,
+        uint32_t provided_password_length, uint8_t **auth_token, uint32_t *auth_token_length,
+        bool *request_reenroll) {
+
+    if (enrolled_password_handle == NULL ||
+            provided_password == NULL) {
+        return -EINVAL;
+    }
+
+    SizedBuffer password_handle_buffer(enrolled_password_handle_length);
+    memcpy(password_handle_buffer.buffer.get(), enrolled_password_handle,
+            enrolled_password_handle_length);
+    SizedBuffer provided_password_buffer(provided_password_length);
+    memcpy(provided_password_buffer.buffer.get(), provided_password, provided_password_length);
+
+    VerifyRequest request(uid, challenge, &password_handle_buffer, &provided_password_buffer);
+    VerifyResponse response;
+
+    impl_->Verify(request, &response);
+
+    if (response.error == ERROR_RETRY) {
+        return response.retry_timeout;
+    } else if (response.error != ERROR_NONE) {
+        return -EINVAL;
+    }
+
+    if (auth_token != NULL && auth_token_length != NULL) {
+       *auth_token = response.auth_token.buffer.release();
+       *auth_token_length = response.auth_token.length;
+    }
+
+    if (request_reenroll != NULL) {
+        *request_reenroll = response.request_reenroll;
+    }
+
+    return 0;
+}
+
+} // namespace i9305
diff --git a/gatekeeper/SoftGateKeeperDevice.h b/gatekeeper/SoftGateKeeperDevice.h
new file mode 100644
index 0000000..05aceaa
--- /dev/null
+++ b/gatekeeper/SoftGateKeeperDevice.h
@@ -0,0 +1,76 @@
+/*
+ * Copyright 2015 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.
+ */
+
+#ifndef SOFT_GATEKEEPER_DEVICE_H_
+#define SOFT_GATEKEEPER_DEVICE_H_
+
+#include "SoftGateKeeper.h"
+
+#include <memory>
+
+using namespace gatekeeper;
+
+namespace i9305 {
+
+/**
+ * Software based GateKeeper implementation
+ */
+class SoftGateKeeperDevice {
+public:
+    SoftGateKeeperDevice() {
+        impl_.reset(new SoftGateKeeper());
+    }
+
+   // Wrappers to translate the gatekeeper HAL API to the Kegyuard Messages API.
+
+    /**
+     * Enrolls password_payload, which should be derived from a user selected pin or password,
+     * with the authentication factor private key used only for enrolling authentication
+     * factor data.
+     *
+     * Returns: 0 on success or an error code less than 0 on error.
+     * On error, enrolled_password_handle will not be allocated.
+     */
+    int enroll(uint32_t uid,
+            const uint8_t *current_password_handle, uint32_t current_password_handle_length,
+            const uint8_t *current_password, uint32_t current_password_length,
+            const uint8_t *desired_password, uint32_t desired_password_length,
+            uint8_t **enrolled_password_handle, uint32_t *enrolled_password_handle_length);
+
+    /**
+     * Verifies provided_password matches enrolled_password_handle.
+     *
+     * Implementations of this module may retain the result of this call
+     * to attest to the recency of authentication.
+     *
+     * On success, writes the address of a verification token to auth_token,
+     * usable to attest password verification to other trusted services. Clients
+     * may pass NULL for this value.
+     *
+     * Returns: 0 on success or an error code less than 0 on error
+     * On error, verification token will not be allocated
+     */
+    int verify(uint32_t uid, uint64_t challenge,
+            const uint8_t *enrolled_password_handle, uint32_t enrolled_password_handle_length,
+            const uint8_t *provided_password, uint32_t provided_password_length,
+            uint8_t **auth_token, uint32_t *auth_token_length, bool *request_reenroll);
+private:
+    std::unique_ptr<SoftGateKeeper> impl_;
+};
+
+} // namespace gatekeeper
+
+#endif //SOFT_GATEKEEPER_DEVICE_H_
diff --git a/gatekeeper/module.cpp b/gatekeeper/module.cpp
new file mode 100644
index 0000000..a3d678c
--- /dev/null
+++ b/gatekeeper/module.cpp
@@ -0,0 +1,127 @@
+/*
+ * Copyright (C) 2015 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.
+ */
+
+#include <hardware/hardware.h>
+#include <hardware/gatekeeper.h>
+#define LOG_TAG "I9305Gatekeeper"
+#include <cutils/log.h>
+
+#include <string.h>
+#include <errno.h>
+#include <stdlib.h>
+
+#include "SoftGateKeeper.h"
+#include "SoftGateKeeperDevice.h"
+
+using i9305::SoftGateKeeperDevice;
+
+struct i9305_gatekeeper_device {
+    gatekeeper_device device;
+    SoftGateKeeperDevice *s_gatekeeper;
+};
+
+static i9305_gatekeeper_device s_device;
+
+static int enroll(const struct gatekeeper_device *dev __unused, uint32_t uid,
+            const uint8_t *current_password_handle, uint32_t current_password_handle_length,
+            const uint8_t *current_password, uint32_t current_password_length,
+            const uint8_t *desired_password, uint32_t desired_password_length,
+            uint8_t **enrolled_password_handle, uint32_t *enrolled_password_handle_length) {
+
+    SoftGateKeeperDevice *s_gatekeeper = ((i9305_gatekeeper_device*)(dev))->s_gatekeeper;
+    ALOGE("called %s with gate keeper %p device %p\n", __func__, s_gatekeeper, dev);
+    if (s_gatekeeper == nullptr)  {
+        abort();
+        return -EINVAL;
+    }
+
+    return s_gatekeeper->enroll(uid,
+            current_password_handle, current_password_handle_length,
+            current_password, current_password_length,
+            desired_password, desired_password_length,
+            enrolled_password_handle, enrolled_password_handle_length);
+}
+
+static int verify(const struct gatekeeper_device *dev __unused, uint32_t uid, uint64_t challenge,
+            const uint8_t *enrolled_password_handle, uint32_t enrolled_password_handle_length,
+            const uint8_t *provided_password, uint32_t provided_password_length,
+            uint8_t **auth_token, uint32_t *auth_token_length, bool *request_reenroll) {
+    SoftGateKeeperDevice *s_gatekeeper = ((i9305_gatekeeper_device*)(dev))->s_gatekeeper;
+    ALOGE("called %s with gate keeper %p device %p\n", __func__, s_gatekeeper, dev);
+    if (s_gatekeeper == nullptr) return -EINVAL;
+    return s_gatekeeper->verify(uid, challenge,
+            enrolled_password_handle, enrolled_password_handle_length,
+            provided_password, provided_password_length,
+            auth_token, auth_token_length, request_reenroll);
+}
+
+static int close_device(hw_device_t* dev __unused) {
+    SoftGateKeeperDevice *s_gatekeeper = ((i9305_gatekeeper_device*)(dev))->s_gatekeeper;
+    if (s_gatekeeper == nullptr) return 0;
+    delete s_gatekeeper;
+    s_gatekeeper = nullptr;
+    ALOGE("called %s with gate keeper %p device %p\n", __func__, s_gatekeeper, dev);
+    return 0;
+}
+
+static int i9305_gatekeeper_open(const hw_module_t *module, const char *name,
+        hw_device_t **device) {
+
+    if (strcmp(name, HARDWARE_GATEKEEPER) != 0) {
+        abort();
+        return -EINVAL;
+    }
+
+    memset(&s_device, 0, sizeof(s_device));
+
+    SoftGateKeeperDevice *s_gatekeeper = new SoftGateKeeperDevice();
+    if (s_gatekeeper == nullptr) return -ENOMEM;
+
+    s_device.s_gatekeeper = s_gatekeeper;
+
+    s_device.device.common.tag = HARDWARE_DEVICE_TAG;
+    s_device.device.common.version = 1;
+    s_device.device.common.module = const_cast<hw_module_t *>(module);
+    s_device.device.common.close = close_device;
+
+    s_device.device.enroll = enroll;
+    s_device.device.verify = verify;
+    s_device.device.delete_user = nullptr;
+    s_device.device.delete_all_users = nullptr;
+
+    *device = &s_device.device.common;
+    ALOGE("called %s with gate keeper %p device %p\n", __func__, s_gatekeeper, *device);
+
+    return 0;
+}
+
+static struct hw_module_methods_t gatekeeper_module_methods = {
+    .open = i9305_gatekeeper_open,
+};
+
+struct gatekeeper_module HAL_MODULE_INFO_SYM __attribute__((visibility("default"))) = {
+    .common = {
+        .tag = HARDWARE_MODULE_TAG,
+        .module_api_version = GATEKEEPER_MODULE_API_VERSION_0_1,
+        .hal_api_version = HARDWARE_HAL_API_VERSION,
+        .id = GATEKEEPER_HARDWARE_MODULE_ID,
+        .name = "I9305 GateKeeper HAL",
+        .author = "The Android Open Source Project",
+        .methods = &gatekeeper_module_methods,
+        .dso = 0,
+        .reserved = {}
+    },
+};