Initial TrustyGateKeeper

8 files changed, 1114 insertions, 0 deletions

diff --git a/LICENSE b/LICENSE
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index 0000000..261eeb9
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@@ -0,0 +1,201 @@
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diff --git a/ipc/gatekeeper_ipc.cpp b/ipc/gatekeeper_ipc.cpp
new file mode 100644
index 0000000..267a629
--- /dev/null
+++ b/ipc/gatekeeper_ipc.cpp
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+/*
+ * 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.
+ */
+
+// TODO: add guard in header
+extern "C" {
+#include <stdlib.h>
+}
+
+#include <string.h>
+#include <stdio.h>
+
+#include <trusty_std.h>
+#include <trusty_ipc.h>
+
+#include <err.h>
+
+#include "trusty_gatekeeper.h"
+#include "gatekeeper_ipc.h"
+
+using namespace gatekeeper;
+TrustyGateKeeper *device;
+
+class SessionManager {
+  public:
+    SessionManager(long* err) {
+        *err = device->OpenSession();
+    }
+    ~SessionManager() {
+        device->CloseSession();
+    }
+};
+
+class MessageDeleter {
+public:
+    explicit MessageDeleter(handle_t chan, int id) {
+        chan_ = chan;
+        id_ = id;
+    }
+
+    ~MessageDeleter() {
+        put_msg(chan_, id_);
+    }
+
+private:
+    handle_t chan_;
+    int id_;
+};
+
+
+static gatekeeper_error_t tipc_err_to_gatekeeper_err(long tipc_err) {
+    switch (tipc_err) {
+        case NO_ERROR:
+            return ERROR_NONE;
+        case ERR_BAD_LEN:
+        case ERR_NOT_VALID:
+        case ERR_NOT_IMPLEMENTED:
+        case ERR_NOT_SUPPORTED:
+            return ERROR_INVALID;
+        default:
+            return ERROR_UNKNOWN;
+    }
+}
+
+template <typename Request, typename Response>
+static gatekeeper_error_t exec_cmd(void (GateKeeper::*operation)(const Request&, Response*),
+                   uint8_t *in_buf, uint32_t in_size,
+                   UniquePtr<uint8_t[]> *out_buf, uint32_t *out_size) {
+    long rc;
+    SessionManager sm(&rc);
+    if (rc != NO_ERROR)
+        return tipc_err_to_gatekeeper_err(rc);
+
+    Request req;
+    gatekeeper_error_t err = req.Deserialize(in_buf, in_buf + in_size);
+    if (err != ERROR_NONE) {
+        TLOGE("error (%d) deserializing request\n", err);
+        return ERROR_INVALID;
+    }
+
+    Response rsp;
+    (device->*operation)(req, &rsp);
+
+    *out_size = rsp.GetSerializedSize();
+    if (*out_size > GATEKEEPER_MAX_BUFFER_LENGTH) {
+        *out_size = 0;
+        TLOGE("response size too large (%d)\n", *out_size);
+        return ERROR_UNKNOWN;
+    }
+
+    out_buf->reset(new uint8_t[*out_size]);
+    if (out_buf->get() == NULL) {
+        *out_size = 0;
+        return ERROR_UNKNOWN;
+    }
+
+    if(rsp.Serialize(out_buf->get(), out_buf->get() + *out_size) != *out_size) {
+        TLOGE("error serializing response message\n");
+        return ERROR_UNKNOWN;
+    }
+
+    return ERROR_NONE;
+}
+
+static gatekeeper_error_t handle_request(uint32_t cmd, uint8_t *in_buf, uint32_t in_buf_size,
+                                         UniquePtr<uint8_t[]> *out_buf, uint32_t *out_buf_size) {
+    switch (cmd) {
+        case GK_ENROLL:
+            return exec_cmd(&GateKeeper::Enroll, in_buf, in_buf_size,
+                    out_buf, out_buf_size);
+        case GK_VERIFY:
+            return exec_cmd(&GateKeeper::Verify, in_buf, in_buf_size,
+                    out_buf, out_buf_size);
+        default:
+            return ERROR_INVALID;
+    }
+}
+
+
+static gatekeeper_error_t send_response(handle_t chan,
+        uint32_t cmd, uint8_t *out_buf, uint32_t out_buf_size) {
+    struct gatekeeper_message gk_msg = { cmd | GK_RESP_BIT };
+    iovec_t iov[2] = {
+        { &gk_msg, sizeof(gk_msg) },
+        { out_buf, out_buf_size },
+    };
+    ipc_msg_t msg = { 2, iov, 0, NULL };
+
+    /* send message back to the caller */
+    long rc = send_msg(chan, &msg);
+
+    // fatal error
+    if (rc < 0) {
+        TLOGE("failed (%d) to send_msg for chan (%d)\n", rc, chan);
+        return tipc_err_to_gatekeeper_err(rc);
+    }
+
+    return ERROR_NONE;
+}
+
+static gatekeeper_error_t send_error_response(handle_t chan, uint32_t cmd, gatekeeper_error_t err) {
+    GateKeeperMessage msg(err);
+    size_t serialized_size = msg.GetSerializedSize();
+    uint8_t *out_buf = new uint8_t[serialized_size];
+    if (out_buf == NULL) {
+        return ERROR_UNKNOWN;
+    }
+
+    msg.Serialize(out_buf, out_buf + serialized_size);
+    gatekeeper_error_t rc = send_response(chan, cmd, out_buf, serialized_size);
+
+    delete[] out_buf;
+    return rc;
+}
+
+
+static long handle_msg(handle_t chan) {
+    /* get message info */
+    ipc_msg_info_t msg_inf;
+
+    long rc = get_msg(chan, &msg_inf);
+    if (rc == ERR_NO_MSG)
+        return ERROR_NONE; /* no new messages */
+
+    // fatal error
+    if (rc != NO_ERROR) {
+        TLOGE("failed (%d) to get_msg for chan (%d), closing connection\n",
+                rc, chan);
+        return rc;
+    }
+
+    MessageDeleter md(chan, msg_inf.id);
+
+    UniquePtr<uint8_t[]> msg_buf(new uint8_t[msg_inf.len]);
+
+    /* read msg content */
+    iovec_t iov = { msg_buf.get(), msg_inf.len };
+    ipc_msg_t msg = { 1, &iov, 0, NULL} ;
+
+    rc = read_msg(chan, msg_inf.id, 0, &msg);
+
+    if (rc < 0) {
+        TLOGE("failed to read msg (%d)\n", rc, chan);
+        return rc;
+    }
+
+    if(((unsigned long) rc) < sizeof(gatekeeper_message)) {
+        TLOGE("invalid message of size (%d)\n", rc, chan);
+        return ERROR_INVALID;
+    }
+
+    /* get request command */
+    gatekeeper_message *gk_msg =
+        reinterpret_cast<struct gatekeeper_message *>(msg_buf.get());
+
+    UniquePtr<uint8_t[]> out_buf;
+    uint32_t out_buf_size = 0;
+    rc = handle_request(gk_msg->cmd, gk_msg->payload,
+            msg_inf.len - sizeof(gatekeeper_message), &out_buf, &out_buf_size);
+
+    if (rc < 0) {
+        TLOGE("unable (%d) to handle request", rc);
+        return send_error_response(chan, gk_msg->cmd, tipc_err_to_gatekeeper_err(rc));
+    }
+
+    rc = send_response(chan, gk_msg->cmd, out_buf.get(), out_buf_size);
+
+    if (rc < 0) {
+        TLOGE("unable (%d) to send response", rc);
+    }
+
+    return rc;
+}
+
+static void gatekeeper_handle_port(uevent_t *ev) {
+    if ((ev->event & IPC_HANDLE_POLL_ERROR) ||
+        (ev->event & IPC_HANDLE_POLL_HUP) ||
+        (ev->event & IPC_HANDLE_POLL_MSG) ||
+        (ev->event & IPC_HANDLE_POLL_SEND_UNBLOCKED)) {
+        /* should never happen with port handles */
+        TLOGE("error event (0x%x) for port (%d)\n",
+               ev->event, ev->handle);
+        abort();
+    }
+
+    uuid_t peer_uuid;
+    if (ev->event & IPC_HANDLE_POLL_READY) {
+        /* incoming connection: accept it */
+        int rc = accept(ev->handle, &peer_uuid);
+        if (rc < 0) {
+            TLOGE("failed (%d) to accept on port %d\n",
+                    rc, ev->handle);
+            return;
+        }
+    }
+}
+
+static void gatekeeper_handle_channel(uevent_t *ev) {
+    if ((ev->event & IPC_HANDLE_POLL_ERROR) ||
+        (ev->event & IPC_HANDLE_POLL_READY)) {
+        /* close it as it is in an error state */
+        TLOGE("error event (0x%x) for chan (%d)\n",
+               ev->event, ev->handle);
+        abort();
+    }
+
+    handle_t chan = ev->handle;
+
+    if (ev->event & IPC_HANDLE_POLL_MSG) {
+        long rc = handle_msg(chan);
+        if (rc != NO_ERROR) {
+            /* report an error and close channel */
+            TLOGE("failed (%d) to handle event on channel %d\n", rc, ev->handle);
+            close(chan);
+        }
+    }
+
+    if (ev->event & IPC_HANDLE_POLL_HUP) {
+        /* closed by peer. */
+        close(chan);
+        return;
+    }
+
+}
+
+static long gatekeeper_ipc_init(void) {
+    int rc;
+
+    /* Initialize service */
+    rc = port_create(GATEKEEPER_PORT, 1, GATEKEEPER_MAX_BUFFER_LENGTH,
+            IPC_PORT_ALLOW_NS_CONNECT);
+    if (rc < 0) {
+        TLOGE("Failed (%d) to create port %s\n", rc, GATEKEEPER_PORT);
+    }
+
+    return rc;
+}
+
+int main(void) {
+    long rc;
+    uevent_t event;
+
+    TLOGI("Initializing\n");
+
+    device = new TrustyGateKeeper();
+
+    rc = gatekeeper_ipc_init();
+    if (rc < 0) {
+        TLOGE("failed (%d) to initialize gatekeeper", rc);
+        return rc;
+    }
+
+    handle_t port = (handle_t) rc;
+
+    /* enter main event loop */
+    while (true) {
+        event.handle = INVALID_IPC_HANDLE;
+        event.event  = 0;
+        event.cookie = NULL;
+
+        rc = wait_any(&event, -1);
+        if (rc < 0) {
+            TLOGE("wait_any failed (%d)\n", rc);
+            break;
+        }
+
+        if (rc == NO_ERROR) { /* got an event */
+            if (event.handle == port) {
+                gatekeeper_handle_port(&event);
+            } else {
+                gatekeeper_handle_channel(&event);
+            }
+        }
+    }
+
+    return 0;
+}
diff --git a/ipc/gatekeeper_ipc.h b/ipc/gatekeeper_ipc.h
new file mode 100644
index 0000000..ed86419
--- /dev/null
+++ b/ipc/gatekeeper_ipc.h
@@ -0,0 +1,38 @@
+/*
+ * 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.
+ */
+
+#define GATEKEEPER_PORT "com.android.trusty.gatekeeper"
+#define GATEKEEPER_MAX_BUFFER_LENGTH 1024
+
+enum gatekeeper_command {
+	GK_REQ_SHIFT = 1,
+	GK_RESP_BIT  = 1,
+
+	GK_ENROLL       = (0 << GK_REQ_SHIFT),
+	GK_VERIFY       = (1 << GK_REQ_SHIFT),
+};
+
+/**
+ * gatekeeper_message - Serial header for communicating with GK server
+ * @cmd: the command, one of ENROLL, VERIFY. Payload must be a serialized
+ *       buffer of the corresponding request object.
+ * @payload: start of the serialized command specific payload
+ */
+struct gatekeeper_message {
+    uint32_t cmd;
+    uint8_t payload[0];
+};
+
diff --git a/ipc/rules.mk b/ipc/rules.mk
new file mode 100644
index 0000000..fdfdcdb
--- /dev/null
+++ b/ipc/rules.mk
@@ -0,0 +1,22 @@
+# 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.
+#
+
+CUR_DIR := $(GET_LOCAL_DIR)
+
+MODULE_SRCS += \
+	$(CUR_DIR)/gatekeeper_ipc.cpp
+
+CUR_DIR =
+
diff --git a/manifest.c b/manifest.c
new file mode 100644
index 0000000..fa80047
--- /dev/null
+++ b/manifest.c
@@ -0,0 +1,35 @@
+/*
+ * 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 <stddef.h>
+#include <trusty_app_manifest.h>
+
+// TODO: generate my own UUID
+trusty_app_manifest_t TRUSTY_APP_MANIFEST_ATTRS trusty_app_manifest =
+{
+
+    /* UUID : {38ba0cdc-df0e-11e4-9869-233fb6ae4795} */
+    { 0x38ba0cdc, 0xdf0e, 0x11e4,
+        { 0x98, 0x69, 0x23, 0x3f, 0xb6, 0xae, 0x47, 0x95 } },
+
+	/* optional configuration options here */
+	{
+		/* openssl need a larger heap */
+		TRUSTY_APP_CONFIG_MIN_HEAP_SIZE(2 * 4096),
+
+		/* openssl need a larger stack */
+		TRUSTY_APP_CONFIG_MIN_STACK_SIZE(1 * 4096),
+	},
+};
diff --git a/rules.mk b/rules.mk
new file mode 100644
index 0000000..15aec82
--- /dev/null
+++ b/rules.mk
@@ -0,0 +1,42 @@
+# 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_DIR := $(GET_LOCAL_DIR)
+
+MODULE := $(LOCAL_DIR)
+
+MODULE_SRCS += \
+	$(LOCAL_DIR)/manifest.c \
+	$(LOCAL_DIR)/trusty_gatekeeper.cpp \
+
+IPC := ipc
+
+MODULE_DEPS += \
+	app/trusty \
+	lib/libc-trusty \
+	lib/libstdc++-trusty \
+	lib/rng \
+	lib/hwkey \
+	lib/storage \
+	lib/keymaster \
+	system/gatekeeper \
+
+MODULE_INCLUDES += \
+	$(LOCAL_DIR)
+
+include $(LOCAL_DIR)/$(IPC)/rules.mk
+
+include make/module.mk
+
diff --git a/trusty_gatekeeper.cpp b/trusty_gatekeeper.cpp
new file mode 100644
index 0000000..26a8a3a
--- /dev/null
+++ b/trusty_gatekeeper.cpp
@@ -0,0 +1,354 @@
+/*
+ * 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.
+ */
+
+#include <openssl/hmac.h>
+#include <err.h>
+
+extern "C" {
+#include <lib/hwkey/hwkey.h>
+#include <lib/keymaster/keymaster.h>
+#include <lib/rng/trusty_rng.h>
+#include <lib/storage/storage.h>
+
+#include <trusty_std.h>
+}
+
+#include "trusty_gatekeeper.h"
+
+#define CALLS_BETWEEN_RNG_RESEEDS 32
+#define RNG_RESEED_SIZE           64
+
+#define HMAC_SHA_256_KEY_SIZE 32
+
+#define GATEKEEPER_PREFIX "gatekeeper."
+
+#define STORAGE_ID_LENGTH_MAX 64
+
+#define MAX_FAILURE_RECORDS 10
+
+namespace gatekeeper {
+
+static const uint8_t DERIVATION_DATA[HMAC_SHA_256_KEY_SIZE] = "TrustyGateKeeperDerivationData0";
+
+TrustyGateKeeper::TrustyGateKeeper() : GateKeeper() {
+    rng_initialized_ = false;
+    calls_since_reseed_ = 0;
+    num_mem_records_ = 0;
+
+    SeedRngIfNeeded();
+}
+
+long TrustyGateKeeper::OpenSession() {
+    if (!SeedRngIfNeeded()) {
+        return ERR_NOT_READY;
+    }
+
+    return DeriveMasterKey();
+}
+
+void TrustyGateKeeper::CloseSession() {
+    ClearMasterKey();
+}
+
+bool TrustyGateKeeper::SeedRngIfNeeded() {
+    if (ShouldReseedRng())
+        rng_initialized_ = ReseedRng();
+    return rng_initialized_;
+}
+
+bool TrustyGateKeeper::ShouldReseedRng() {
+    if (!rng_initialized_) {
+        return true;
+    }
+
+    if (++calls_since_reseed_ % CALLS_BETWEEN_RNG_RESEEDS == 0) {
+        return true;
+    }
+    return false;
+}
+
+bool TrustyGateKeeper::ReseedRng() {
+    UniquePtr<uint8_t[]> rand_seed(new uint8_t[RNG_RESEED_SIZE]);
+    memset(rand_seed.get(), 0, RNG_RESEED_SIZE);
+    if (trusty_rng_secure_rand(rand_seed.get(), RNG_RESEED_SIZE) != NO_ERROR) {
+        return false;
+    }
+
+    trusty_rng_add_entropy(rand_seed.get(), RNG_RESEED_SIZE);
+    return true;
+}
+
+long TrustyGateKeeper::DeriveMasterKey() {
+    long rc = hwkey_open();
+    if (rc < 0) {
+        return rc;
+    }
+
+    hwkey_session_t session = (hwkey_session_t) rc;
+
+    master_key_.reset(new uint8_t[HMAC_SHA_256_KEY_SIZE]);
+
+    uint32_t kdf_version = HWKEY_KDF_VERSION_1;
+    rc = hwkey_derive(session, &kdf_version, DERIVATION_DATA, master_key_.get(),
+            HMAC_SHA_256_KEY_SIZE);
+
+    hwkey_close(session);
+    return rc;
+}
+
+void TrustyGateKeeper::ClearMasterKey() {
+    memset_s(master_key_.get(), 0, HMAC_SHA_256_KEY_SIZE);
+    master_key_.reset();
+}
+
+bool TrustyGateKeeper::GetAuthTokenKey(const uint8_t **auth_token_key,
+        size_t *length) const {
+    *length = 0;
+    *auth_token_key = NULL;
+
+    long rc = keymaster_open();
+    if (rc < 0) {
+        return false;
+    }
+
+    keymaster_session_t session = (keymaster_session_t) rc;
+
+    uint8_t *key = NULL;
+	uint32_t local_length = 0;
+
+    rc = keymaster_get_auth_token_key(session, &key, &local_length);
+    keymaster_close(session);
+
+    if (rc == NO_ERROR) {
+        *auth_token_key = key;
+		*length = local_length;
+        return true;
+    } else {
+        return false;
+    }
+}
+
+void TrustyGateKeeper::GetPasswordKey(const uint8_t **password_key, size_t *length) {
+    *password_key = const_cast<const uint8_t *>(master_key_.get());
+    *length = HMAC_SHA_256_KEY_SIZE;
+}
+
+void TrustyGateKeeper::ComputePasswordSignature(uint8_t *signature, size_t signature_length,
+        const uint8_t *key, size_t key_length, const uint8_t *password,
+        size_t password_length, salt_t salt) const {
+    // todo: heap allocate
+    uint8_t salted_password[password_length + sizeof(salt)];
+    memcpy(salted_password, &salt, sizeof(salt));
+    memcpy(salted_password + sizeof(salt), password, password_length);
+    ComputeSignature(signature, signature_length, key, key_length, salted_password,
+            password_length + sizeof(salt));
+}
+
+void TrustyGateKeeper::GetRandom(void *random, size_t requested_size) const {
+    if (random == NULL) return;
+    trusty_rng_secure_rand(reinterpret_cast<uint8_t*>(random), requested_size);
+}
+
+void TrustyGateKeeper::ComputeSignature(uint8_t *signature, size_t signature_length,
+        const uint8_t *key, size_t key_length, const uint8_t *message,
+        const size_t length) const {
+    uint8_t buf[HMAC_SHA_256_KEY_SIZE];
+    size_t buf_len;
+
+    HMAC(EVP_sha256(), key, key_length, message, length, buf, &buf_len);
+    size_t to_write = buf_len;
+    if (buf_len > signature_length) to_write = signature_length;
+    memset(signature, 0, signature_length);
+    memcpy(signature, buf, to_write);
+}
+
+uint64_t TrustyGateKeeper::GetMillisecondsSinceBoot() const {
+    status_t rc;
+    int64_t secure_time_ns = 0;
+    rc = gettime(0, 0, &secure_time_ns);
+    if (rc != NO_ERROR){
+        secure_time_ns = 0;
+        TLOGE("%s Error:[0x%x].\n", __func__, rc);
+    }
+    return secure_time_ns / 1000 / 1000;
+}
+
+bool TrustyGateKeeper::GetSecureFailureRecord(uint32_t uid, secure_id_t user_id,
+        failure_record_t *record) {
+
+	storage_session_t session;
+    int rc = storage_open_session(&session);
+    if (rc < 0) {
+        TLOGE("Error: [%d] opening storage session\n", rc);
+        return false;
+    }
+
+    char id[STORAGE_ID_LENGTH_MAX];
+    memset(id, 0, sizeof(id));
+
+	file_handle_t handle;
+    snprintf(id, STORAGE_ID_LENGTH_MAX, GATEKEEPER_PREFIX "%u", uid);
+    rc = storage_open_file(session, &handle, id, 0);
+    if (rc < 0) {
+        TLOGE("Error:[%d] opening storage object.\n", rc);
+        return false;
+    }
+
+    failure_record_t owner_record;
+    rc = storage_read(session, handle, 0, &owner_record, sizeof(owner_record));
+    storage_close_file(session, handle);
+    storage_close_session(session);
+
+    if (rc < 0) {
+        TLOGE("Error:[%d] reading storage object.\n", rc);
+        return false;
+    }
+
+    if ((size_t) rc < sizeof(owner_record)) {
+        TLOGE("Error: invalid object size [%d].\n", rc);
+        return false;
+    }
+
+    if (owner_record.secure_user_id != user_id) {
+        TLOGE("Error:[%llu != %llu] secure storage corrupt.\n",
+                owner_record.secure_user_id, user_id);
+        return false;
+    }
+
+    *record = owner_record;
+    return true;
+}
+
+bool TrustyGateKeeper::GetFailureRecord(uint32_t uid, secure_id_t user_id, failure_record_t *record,
+        bool secure) {
+    if (secure) {
+        return GetSecureFailureRecord(uid, user_id, record);
+    } else {
+        return GetMemoryRecord(user_id, record);
+    }
+}
+
+bool TrustyGateKeeper::ClearFailureRecord(uint32_t uid, secure_id_t user_id, bool secure) {
+    failure_record_t record;
+    record.secure_user_id = user_id;
+    record.last_checked_timestamp = 0;
+    record.failure_counter = 0;
+    return WriteFailureRecord(uid, &record, secure);
+}
+
+bool TrustyGateKeeper::WriteSecureFailureRecord(uint32_t uid, failure_record_t *record) {
+	storage_session_t session;
+    long rc = storage_open_session(&session);
+    if (rc < 0) {
+        TLOGE("Error: [%d] failed to open storage session\n", rc);
+        return false;
+    }
+
+    char id[STORAGE_ID_LENGTH_MAX];
+    memset(id, 0, sizeof(id));
+    snprintf(id, STORAGE_ID_LENGTH_MAX, GATEKEEPER_PREFIX "%u", uid);
+
+	file_handle_t handle;
+    rc = storage_open_file(session, &handle, id, STORAGE_OPEN_CREATE);
+    if (rc < 0) {
+        TLOGE("Error: [%d] failed to open storage object %s\n", rc, id);
+        return false;
+    }
+
+    rc = storage_write(session, handle, 0, record, sizeof(*record));
+    storage_close_file(session, handle);
+    storage_close_session(session);
+
+    if (rc < 0) {
+        TLOGE("Error:[%d] writing storage object.\n", rc);
+        return false;
+    }
+
+    if ((size_t) rc < sizeof(*record)) {
+        TLOGE("Error: invalid object size [%d].\n", rc);
+        return false;
+    }
+
+    return true;
+}
+
+bool TrustyGateKeeper::WriteFailureRecord(uint32_t uid, failure_record_t *record, bool secure) {
+    if (secure) {
+        return WriteSecureFailureRecord(uid, record);
+    } else {
+        return WriteMemoryRecord(record);
+    }
+}
+
+bool TrustyGateKeeper::IsHardwareBacked() const {
+    return true;
+}
+
+void TrustyGateKeeper::InitMemoryRecords() {
+    if (!mem_records_.get()) {
+        failure_record_t *mem_recs = new failure_record_t[MAX_FAILURE_RECORDS];
+        memset(mem_recs, 0, sizeof(*mem_recs));
+        mem_records_.reset(mem_recs);
+        num_mem_records_ = 0;
+    }
+}
+
+bool TrustyGateKeeper::GetMemoryRecord(secure_id_t user_id, failure_record_t *record) {
+    InitMemoryRecords();
+
+    for (int i = 0; i < num_mem_records_; i++) {
+        if (mem_records_[i].secure_user_id == user_id) {
+            *record = mem_records_[i];
+            return true;
+        }
+    }
+
+    record->secure_user_id = user_id;
+    record->failure_counter = 0;
+    record->last_checked_timestamp = 0;
+
+    return true;
+}
+
+bool TrustyGateKeeper::WriteMemoryRecord(failure_record_t *record) {
+    InitMemoryRecords();
+
+    int idx = 0;
+    int min_idx = 0;
+    uint64_t min_timestamp = ~0ULL;
+    for (idx = 0; idx < num_mem_records_; idx++) {
+        if (mem_records_[idx].secure_user_id == record->secure_user_id) {
+            break;
+        }
+
+        if (mem_records_[idx].last_checked_timestamp <= min_timestamp) {
+            min_timestamp = mem_records_[idx].last_checked_timestamp;
+            min_idx = idx;
+        }
+    }
+
+    if (idx >= MAX_FAILURE_RECORDS) {
+        // replace oldest element
+        idx = min_idx;
+    } else if (idx == num_mem_records_) {
+        num_mem_records_++;
+    }
+
+    mem_records_[idx] = *record;
+    return true;
+}
+
+}
diff --git a/trusty_gatekeeper.h b/trusty_gatekeeper.h
new file mode 100644
index 0000000..1235feb
--- /dev/null
+++ b/trusty_gatekeeper.h
@@ -0,0 +1,93 @@
+/*
+ * 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 TRUSTY_GATEKEEPER_H_
+#define TRUSTY_GATEKEEPER_H_
+
+#include <trusty_std.h>
+#include <stdio.h>
+
+#include <gatekeeper/gatekeeper.h>
+
+#define LOG_TAG "trusty_gatekeeper"
+#define TLOGE(fmt, ...) \
+    fprintf(stderr, "%s: %d: " fmt, LOG_TAG, __LINE__,  ## __VA_ARGS__)
+
+#if LOCAL_TRACE
+#define TLOGI(fmt, ...) \
+    fprintf(stderr, "%s: %d: " fmt, LOG_TAG, __LINE__,  ## __VA_ARGS__)
+#else
+#define TLOGI(fmt, ...)
+#endif
+
+namespace gatekeeper {
+
+class TrustyGateKeeper : public GateKeeper {
+public:
+    TrustyGateKeeper();
+
+    long OpenSession();
+    void CloseSession();
+protected:
+    // See gatekeeper/gatekeeper.h for documentation
+
+    virtual bool GetAuthTokenKey(const uint8_t **auth_token_key, size_t *length) const;
+
+    virtual void GetPasswordKey(const uint8_t **password_key, size_t *length);
+
+    virtual void ComputePasswordSignature(uint8_t *signature, size_t signature_length,
+            const uint8_t *key, size_t key_length, const uint8_t *password,
+            size_t password_length, salt_t salt) const;
+
+    virtual void GetRandom(void *random, size_t requested_size) const;
+    virtual void ComputeSignature(uint8_t *signature, size_t signature_length,
+            const uint8_t *key, size_t key_length, const uint8_t *message,
+            const size_t length) const;
+    virtual uint64_t GetMillisecondsSinceBoot() const;
+
+    virtual bool GetFailureRecord(uint32_t uid, secure_id_t user_id, failure_record_t *record,
+            bool secure);
+    virtual bool WriteFailureRecord(uint32_t uid, failure_record_t *record, bool secure);
+    virtual bool ClearFailureRecord(uint32_t uid, secure_id_t user_id, bool secure);
+
+    virtual bool IsHardwareBacked() const;
+
+private:
+    bool SeedRngIfNeeded();
+    bool ShouldReseedRng();
+    bool ReseedRng();
+
+    long DeriveMasterKey();
+    void ClearMasterKey();
+
+    void InitMemoryRecords();
+    bool GetMemoryRecord(secure_id_t user_id, failure_record_t *record);
+    bool WriteMemoryRecord(failure_record_t *record);
+    bool GetSecureFailureRecord(uint32_t uid, secure_id_t user_id,
+            failure_record_t *record);
+    bool WriteSecureFailureRecord(uint32_t uid, failure_record_t *record);
+
+    UniquePtr<uint8_t[]> master_key_;
+    bool rng_initialized_;
+    int calls_since_reseed_;
+
+    int num_mem_records_;
+    UniquePtr<failure_record_t[]> mem_records_;
+};
+
+}
+
+#endif // TRUSTY_GATEKEEPER_H_