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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 
     19 #include <assert.h>
     20 
     21 #include <keymaster/new>
     22 
     23 #include <keymaster/android_keymaster_utils.h>
     24 
     25 namespace keymaster {
     26 
     27 uint8_t* append_to_buf(uint8_t* buf, const uint8_t* end, const void* data, size_t data_len) {
     28     if (__pval(buf) + data_len < __pval(buf))  // Pointer wrap check
     29         return buf;
     30 
     31     if (buf + data_len <= end) {
     32         memcpy(buf, data, data_len);
     33         return buf + data_len;
     34     }
     35     return buf;
     36 }
     37 
     38 bool copy_from_buf(const uint8_t** buf_ptr, const uint8_t* end, void* dest, size_t size) {
     39     if (__pval(*buf_ptr) + size < __pval(*buf_ptr))  // Pointer wrap check
     40         return false;
     41 
     42     if (end < *buf_ptr + size)
     43         return false;
     44     memcpy(dest, *buf_ptr, size);
     45     *buf_ptr += size;
     46     return true;
     47 }
     48 
     49 bool copy_size_and_data_from_buf(const uint8_t** buf_ptr, const uint8_t* end, size_t* size,
     50                                  UniquePtr<uint8_t[]>* dest) {
     51     if (!copy_uint32_from_buf(buf_ptr, end, size))
     52         return false;
     53 
     54     if (__pval(*buf_ptr) + *size < __pval(*buf_ptr))  // Pointer wrap check
     55         return false;
     56 
     57     if (*buf_ptr + *size > end)
     58         return false;
     59 
     60     if (*size == 0) {
     61         dest->reset();
     62         return true;
     63     }
     64     dest->reset(new (std::nothrow) uint8_t[*size]);
     65     if (!dest->get())
     66         return false;
     67     return copy_from_buf(buf_ptr, end, dest->get(), *size);
     68 }
     69 
     70 bool Buffer::reserve(size_t size) {
     71     if (available_write() < size) {
     72         size_t new_size = buffer_size_ + size - available_write();
     73         uint8_t* new_buffer = new (std::nothrow) uint8_t[new_size];
     74         if (!new_buffer)
     75             return false;
     76         memcpy(new_buffer, buffer_.get() + read_position_, available_read());
     77         memset_s(buffer_.get(), 0, buffer_size_);
     78         buffer_.reset(new_buffer);
     79         buffer_size_ = new_size;
     80         write_position_ -= read_position_;
     81         read_position_ = 0;
     82     }
     83     return true;
     84 }
     85 
     86 bool Buffer::Reinitialize(size_t size) {
     87     Clear();
     88     buffer_.reset(new (std::nothrow) uint8_t[size]);
     89     if (!buffer_.get())
     90         return false;
     91     buffer_size_ = size;
     92     read_position_ = 0;
     93     write_position_ = 0;
     94     return true;
     95 }
     96 
     97 bool Buffer::Reinitialize(const void* data, size_t data_len) {
     98     Clear();
     99     if (__pval(data) + data_len < __pval(data))  // Pointer wrap check
    100         return false;
    101     buffer_.reset(new (std::nothrow) uint8_t[data_len]);
    102     if (!buffer_.get())
    103         return false;
    104     buffer_size_ = data_len;
    105     memcpy(buffer_.get(), data, data_len);
    106     read_position_ = 0;
    107     write_position_ = buffer_size_;
    108     return true;
    109 }
    110 
    111 size_t Buffer::available_write() const {
    112     assert(buffer_size_ >= write_position_);
    113     return buffer_size_ - write_position_;
    114 }
    115 
    116 size_t Buffer::available_read() const {
    117     assert(buffer_size_ >= write_position_);
    118     assert(write_position_ >= read_position_);
    119     return write_position_ - read_position_;
    120 }
    121 
    122 bool Buffer::write(const uint8_t* src, size_t write_length) {
    123     if (available_write() < write_length)
    124         return false;
    125     memcpy(buffer_.get() + write_position_, src, write_length);
    126     write_position_ += write_length;
    127     return true;
    128 }
    129 
    130 bool Buffer::read(uint8_t* dest, size_t read_length) {
    131     if (available_read() < read_length)
    132         return false;
    133     memcpy(dest, buffer_.get() + read_position_, read_length);
    134     read_position_ += read_length;
    135     return true;
    136 }
    137 
    138 size_t Buffer::SerializedSize() const {
    139     return sizeof(uint32_t) + available_read();
    140 }
    141 
    142 uint8_t* Buffer::Serialize(uint8_t* buf, const uint8_t* end) const {
    143     return append_size_and_data_to_buf(buf, end, peek_read(), available_read());
    144 }
    145 
    146 bool Buffer::Deserialize(const uint8_t** buf_ptr, const uint8_t* end) {
    147     Clear();
    148     if (!copy_size_and_data_from_buf(buf_ptr, end, &buffer_size_, &buffer_)) {
    149         buffer_.reset();
    150         buffer_size_ = 0;
    151         return false;
    152     }
    153     write_position_ = buffer_size_;
    154     return true;
    155 }
    156 
    157 void Buffer::Clear() {
    158     memset_s(buffer_.get(), 0, buffer_size_);
    159     buffer_.reset();
    160     read_position_ = 0;
    161     write_position_ = 0;
    162     buffer_size_ = 0;
    163 }
    164 
    165 }  // namespace keymaster
    166