trusty/keymaster/trusty_keymaster_ipc.cpp

/*
 * 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 LOG_TAG "TrustyKeymaster"

// TODO: make this generic in libtrusty

#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include <log/log.h>
#include <trusty/tipc.h>

#include "keymaster_ipc.h"
#include "trusty_keymaster_ipc.h"

#define TRUSTY_DEVICE_NAME "/dev/trusty-ipc-dev0"

static int handle_ = 0;

int trusty_keymaster_connect() {
    int rc = tipc_connect(TRUSTY_DEVICE_NAME, KEYMASTER_PORT);
    if (rc < 0) {
        return rc;
    }

    handle_ = rc;
    return 0;
}

int trusty_keymaster_call(uint32_t cmd, void* in, uint32_t in_size, uint8_t* out,
                          uint32_t* out_size) {
    if (handle_ == 0) {
        ALOGE("not connected\n");
        return -EINVAL;
    }

    size_t msg_size = in_size + sizeof(struct keymaster_message);
    struct keymaster_message* msg = reinterpret_cast<struct keymaster_message*>(malloc(msg_size));
    msg->cmd = cmd;
    memcpy(msg->payload, in, in_size);

    ssize_t rc = write(handle_, msg, msg_size);
    free(msg);

    if (rc < 0) {
        ALOGE("failed to send cmd (%d) to %s: %s\n", cmd, KEYMASTER_PORT, strerror(errno));
        return -errno;
    }

    rc = read(handle_, out, *out_size);
    if (rc < 0) {
        ALOGE("failed to retrieve response for cmd (%d) to %s: %s\n", cmd, KEYMASTER_PORT,
              strerror(errno));
        return -errno;
    }

    if ((size_t)rc < sizeof(struct keymaster_message)) {
        ALOGE("invalid response size (%d)\n", (int)rc);
        return -EINVAL;
    }

    msg = (struct keymaster_message*)out;

    if ((cmd | KEYMASTER_RESP_BIT) != msg->cmd) {
        ALOGE("invalid command (%d)", msg->cmd);
        return -EINVAL;
    }

    *out_size = ((size_t)rc) - sizeof(struct keymaster_message);
    return rc;
}

void trusty_keymaster_disconnect() {
    if (handle_ != 0) {
        tipc_close(handle_);
    }
}