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      1 /*
      2  * Copyright 2014 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #include <keymaster/serializable.h>
     18 #include <keymaster/google_keymaster_utils.h>
     19 
     20 namespace keymaster {
     21 
     22 uint8_t* append_to_buf(uint8_t* buf, const uint8_t* end, const void* data, size_t data_len) {
     23     if (buf + data_len <= end)
     24         memcpy(buf, data, data_len);
     25     return buf + data_len;
     26 }
     27 
     28 bool copy_from_buf(const uint8_t** buf_ptr, const uint8_t* end, void* dest, size_t size) {
     29     if (end < *buf_ptr + size)
     30         return false;
     31     memcpy(dest, *buf_ptr, size);
     32     *buf_ptr += size;
     33     return true;
     34 }
     35 
     36 bool copy_size_and_data_from_buf(const uint8_t** buf_ptr, const uint8_t* end, size_t* size,
     37                                  UniquePtr<uint8_t[]>* dest) {
     38     if (!copy_uint32_from_buf(buf_ptr, end, size) || *buf_ptr + *size > end) {
     39         return false;
     40     }
     41     if (*size == 0) {
     42         dest->reset();
     43         return true;
     44     }
     45     dest->reset(new uint8_t[*size]);
     46     if (dest->get() == NULL)
     47         return false;
     48     return copy_from_buf(buf_ptr, end, dest->get(), *size);
     49 }
     50 
     51 bool Buffer::reserve(size_t size) {
     52     if (available_write() < size) {
     53         size_t new_size = buffer_size_ + size - available_write();
     54         uint8_t* new_buffer = new uint8_t[new_size];
     55         if (!new_buffer)
     56             return false;
     57         memcpy(new_buffer, buffer_.get() + read_position_, available_read());
     58         memset_s(buffer_.get(), 0, buffer_size_);
     59         buffer_.reset(new_buffer);
     60         buffer_size_ = new_size;
     61         write_position_ -= read_position_;
     62         read_position_ = 0;
     63     }
     64     return true;
     65 }
     66 
     67 bool Buffer::Reinitialize(size_t size) {
     68     Clear();
     69     buffer_.reset(new uint8_t[size]);
     70     if (buffer_.get() == NULL)
     71         return false;
     72     buffer_size_ = size;
     73     read_position_ = 0;
     74     write_position_ = 0;
     75     return true;
     76 }
     77 
     78 bool Buffer::Reinitialize(const void* data, size_t data_len) {
     79     Clear();
     80     buffer_.reset(new uint8_t[data_len]);
     81     if (buffer_.get() == NULL)
     82         return false;
     83     buffer_size_ = data_len;
     84     memcpy(buffer_.get(), data, data_len);
     85     read_position_ = 0;
     86     write_position_ = buffer_size_;
     87     return true;
     88 }
     89 
     90 size_t Buffer::available_write() const {
     91     return buffer_size_ - write_position_;
     92 }
     93 
     94 size_t Buffer::available_read() const {
     95     return write_position_ - read_position_;
     96 }
     97 
     98 bool Buffer::write(const uint8_t* src, size_t write_length) {
     99     if (available_write() < write_length)
    100         return false;
    101     memcpy(buffer_.get() + write_position_, src, write_length);
    102     write_position_ += write_length;
    103     return true;
    104 }
    105 
    106 bool Buffer::read(uint8_t* dest, size_t read_length) {
    107     if (available_read() < read_length)
    108         return false;
    109     memcpy(dest, buffer_.get() + read_position_, read_length);
    110     read_position_ += read_length;
    111     return true;
    112 }
    113 
    114 size_t Buffer::SerializedSize() const {
    115     return sizeof(uint32_t) + available_read();
    116 }
    117 
    118 uint8_t* Buffer::Serialize(uint8_t* buf, const uint8_t* end) const {
    119     return append_size_and_data_to_buf(buf, end, peek_read(), available_read());
    120 }
    121 
    122 bool Buffer::Deserialize(const uint8_t** buf_ptr, const uint8_t* end) {
    123     Clear();
    124     if (!copy_size_and_data_from_buf(buf_ptr, end, &buffer_size_, &buffer_)) {
    125         buffer_.reset();
    126         buffer_size_ = 0;
    127         return false;
    128     }
    129     write_position_ = buffer_size_;
    130     return true;
    131 }
    132 
    133 void Buffer::Clear() {
    134     if (buffer_.get())
    135         memset_s(buffer_.get(), 0, buffer_size_);
    136     buffer_.reset();
    137     read_position_ = 0;
    138     write_position_ = 0;
    139     buffer_size_ = 0;
    140 }
    141 
    142 }  // namespace keymaster
    143