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<div class="fragment"><div class="line"><a name="l00001"></a><span class="lineno"> 1</span>&#160;<span class="comment">// Copyright 2015 Google Inc. All rights reserved.</span></div>
<div class="line"><a name="l00002"></a><span class="lineno"> 2</span>&#160;<span class="comment">//</span></div>
<div class="line"><a name="l00003"></a><span class="lineno"> 3</span>&#160;<span class="comment">// Use of this source code is governed by a BSD-style</span></div>
<div class="line"><a name="l00004"></a><span class="lineno"> 4</span>&#160;<span class="comment">// license that can be found in the LICENSE file or at</span></div>
<div class="line"><a name="l00005"></a><span class="lineno"> 5</span>&#160;<span class="comment">// https://developers.google.com/open-source/licenses/bsd</span></div>
<div class="line"><a name="l00006"></a><span class="lineno"> 6</span>&#160;</div>
<div class="line"><a name="l00007"></a><span class="lineno"> 7</span>&#160;<span class="preprocessor">#include &quot;packager/media/formats/webm/encryptor.h&quot;</span></div>
<div class="line"><a name="l00008"></a><span class="lineno"> 8</span>&#160;</div>
<div class="line"><a name="l00009"></a><span class="lineno"> 9</span>&#160;<span class="preprocessor">#include &quot;packager/media/base/buffer_writer.h&quot;</span></div>
<div class="line"><a name="l00010"></a><span class="lineno"> 10</span>&#160;<span class="preprocessor">#include &quot;packager/media/base/media_sample.h&quot;</span></div>
<div class="line"><a name="l00011"></a><span class="lineno"> 11</span>&#160;<span class="preprocessor">#include &quot;packager/media/formats/webm/webm_constants.h&quot;</span></div>
<div class="line"><a name="l00012"></a><span class="lineno"> 12</span>&#160;</div>
<div class="line"><a name="l00013"></a><span class="lineno"> 13</span>&#160;<span class="keyword">namespace </span>shaka {</div>
<div class="line"><a name="l00014"></a><span class="lineno"> 14</span>&#160;<span class="keyword">namespace </span>media {</div>
<div class="line"><a name="l00015"></a><span class="lineno"> 15</span>&#160;<span class="keyword">namespace </span>webm {</div>
<div class="line"><a name="l00016"></a><span class="lineno"> 16</span>&#160;</div>
<div class="line"><a name="l00017"></a><span class="lineno"> 17</span>&#160;Status UpdateTrackForEncryption(<span class="keyword">const</span> std::vector&lt;uint8_t&gt;&amp; key_id,</div>
<div class="line"><a name="l00018"></a><span class="lineno"> 18</span>&#160; mkvmuxer::Track* track) {</div>
<div class="line"><a name="l00019"></a><span class="lineno"> 19</span>&#160; DCHECK_EQ(track-&gt;content_encoding_entries_size(), 0u);</div>
<div class="line"><a name="l00020"></a><span class="lineno"> 20</span>&#160;</div>
<div class="line"><a name="l00021"></a><span class="lineno"> 21</span>&#160; <span class="keywordflow">if</span> (!track-&gt;AddContentEncoding()) {</div>
<div class="line"><a name="l00022"></a><span class="lineno"> 22</span>&#160; <span class="keywordflow">return</span> Status(error::INTERNAL_ERROR,</div>
<div class="line"><a name="l00023"></a><span class="lineno"> 23</span>&#160; <span class="stringliteral">&quot;Could not add ContentEncoding to track.&quot;</span>);</div>
<div class="line"><a name="l00024"></a><span class="lineno"> 24</span>&#160; }</div>
<div class="line"><a name="l00025"></a><span class="lineno"> 25</span>&#160;</div>
<div class="line"><a name="l00026"></a><span class="lineno"> 26</span>&#160; mkvmuxer::ContentEncoding* <span class="keyword">const</span> encoding =</div>
<div class="line"><a name="l00027"></a><span class="lineno"> 27</span>&#160; track-&gt;GetContentEncodingByIndex(0);</div>
<div class="line"><a name="l00028"></a><span class="lineno"> 28</span>&#160; <span class="keywordflow">if</span> (!encoding) {</div>
<div class="line"><a name="l00029"></a><span class="lineno"> 29</span>&#160; <span class="keywordflow">return</span> Status(error::INTERNAL_ERROR,</div>
<div class="line"><a name="l00030"></a><span class="lineno"> 30</span>&#160; <span class="stringliteral">&quot;Could not add ContentEncoding to track.&quot;</span>);</div>
<div class="line"><a name="l00031"></a><span class="lineno"> 31</span>&#160; }</div>
<div class="line"><a name="l00032"></a><span class="lineno"> 32</span>&#160;</div>
<div class="line"><a name="l00033"></a><span class="lineno"> 33</span>&#160; mkvmuxer::ContentEncAESSettings* <span class="keyword">const</span> aes = encoding-&gt;enc_aes_settings();</div>
<div class="line"><a name="l00034"></a><span class="lineno"> 34</span>&#160; <span class="keywordflow">if</span> (!aes) {</div>
<div class="line"><a name="l00035"></a><span class="lineno"> 35</span>&#160; <span class="keywordflow">return</span> Status(error::INTERNAL_ERROR,</div>
<div class="line"><a name="l00036"></a><span class="lineno"> 36</span>&#160; <span class="stringliteral">&quot;Error getting ContentEncAESSettings.&quot;</span>);</div>
<div class="line"><a name="l00037"></a><span class="lineno"> 37</span>&#160; }</div>
<div class="line"><a name="l00038"></a><span class="lineno"> 38</span>&#160; <span class="keywordflow">if</span> (aes-&gt;cipher_mode() != mkvmuxer::ContentEncAESSettings::kCTR) {</div>
<div class="line"><a name="l00039"></a><span class="lineno"> 39</span>&#160; <span class="keywordflow">return</span> Status(error::INTERNAL_ERROR, <span class="stringliteral">&quot;Cipher Mode is not CTR.&quot;</span>);</div>
<div class="line"><a name="l00040"></a><span class="lineno"> 40</span>&#160; }</div>
<div class="line"><a name="l00041"></a><span class="lineno"> 41</span>&#160;</div>
<div class="line"><a name="l00042"></a><span class="lineno"> 42</span>&#160; <span class="keywordflow">if</span> (!encoding-&gt;SetEncryptionID(key_id.data(), key_id.size())) {</div>
<div class="line"><a name="l00043"></a><span class="lineno"> 43</span>&#160; <span class="keywordflow">return</span> Status(error::INTERNAL_ERROR, <span class="stringliteral">&quot;Error setting encryption ID.&quot;</span>);</div>
<div class="line"><a name="l00044"></a><span class="lineno"> 44</span>&#160; }</div>
<div class="line"><a name="l00045"></a><span class="lineno"> 45</span>&#160; <span class="keywordflow">return</span> Status::OK;</div>
<div class="line"><a name="l00046"></a><span class="lineno"> 46</span>&#160;}</div>
<div class="line"><a name="l00047"></a><span class="lineno"> 47</span>&#160;</div>
<div class="line"><a name="l00048"></a><span class="lineno"> 48</span>&#160;<span class="keywordtype">void</span> UpdateFrameForEncryption(MediaSample* sample) {</div>
<div class="line"><a name="l00049"></a><span class="lineno"> 49</span>&#160; <span class="keyword">const</span> <span class="keywordtype">size_t</span> sample_size = sample-&gt;data_size();</div>
<div class="line"><a name="l00050"></a><span class="lineno"> 50</span>&#160; <span class="keywordflow">if</span> (sample-&gt;decrypt_config()) {</div>
<div class="line"><a name="l00051"></a><span class="lineno"> 51</span>&#160; <span class="keyword">auto</span>* decrypt_config = sample-&gt;decrypt_config();</div>
<div class="line"><a name="l00052"></a><span class="lineno"> 52</span>&#160; <span class="keyword">const</span> <span class="keywordtype">size_t</span> iv_size = decrypt_config-&gt;iv().size();</div>
<div class="line"><a name="l00053"></a><span class="lineno"> 53</span>&#160; DCHECK_EQ(iv_size, kWebMIvSize);</div>
<div class="line"><a name="l00054"></a><span class="lineno"> 54</span>&#160; <span class="keywordflow">if</span> (!decrypt_config-&gt;subsamples().empty()) {</div>
<div class="line"><a name="l00055"></a><span class="lineno"> 55</span>&#160; <span class="keyword">auto</span>&amp; subsamples = decrypt_config-&gt;subsamples();</div>
<div class="line"><a name="l00056"></a><span class="lineno"> 56</span>&#160; <span class="comment">// Use partitioned subsample encryption: | signal_byte(3) | iv</span></div>
<div class="line"><a name="l00057"></a><span class="lineno"> 57</span>&#160; <span class="comment">// | num_partitions | partition_offset * n | enc_data |</span></div>
<div class="line"><a name="l00058"></a><span class="lineno"> 58</span>&#160; DCHECK_LT(subsamples.size(), kWebMMaxSubsamples);</div>
<div class="line"><a name="l00059"></a><span class="lineno"> 59</span>&#160; <span class="keyword">const</span> <span class="keywordtype">size_t</span> num_partitions =</div>
<div class="line"><a name="l00060"></a><span class="lineno"> 60</span>&#160; 2 * subsamples.size() - 1 -</div>
<div class="line"><a name="l00061"></a><span class="lineno"> 61</span>&#160; (subsamples.back().cipher_bytes == 0 ? 1 : 0);</div>
<div class="line"><a name="l00062"></a><span class="lineno"> 62</span>&#160; <span class="keyword">const</span> <span class="keywordtype">size_t</span> header_size = kWebMSignalByteSize + iv_size +</div>
<div class="line"><a name="l00063"></a><span class="lineno"> 63</span>&#160; kWebMNumPartitionsSize +</div>
<div class="line"><a name="l00064"></a><span class="lineno"> 64</span>&#160; (kWebMPartitionOffsetSize * num_partitions);</div>
<div class="line"><a name="l00065"></a><span class="lineno"> 65</span>&#160; sample-&gt;resize_data(header_size + sample_size);</div>
<div class="line"><a name="l00066"></a><span class="lineno"> 66</span>&#160; uint8_t* sample_data = sample-&gt;writable_data();</div>
<div class="line"><a name="l00067"></a><span class="lineno"> 67</span>&#160; memmove(sample_data + header_size, sample_data, sample_size);</div>
<div class="line"><a name="l00068"></a><span class="lineno"> 68</span>&#160; sample_data[0] = kWebMEncryptedSignal | kWebMPartitionedSignal;</div>
<div class="line"><a name="l00069"></a><span class="lineno"> 69</span>&#160; memcpy(sample_data + kWebMSignalByteSize, decrypt_config-&gt;iv().data(),</div>
<div class="line"><a name="l00070"></a><span class="lineno"> 70</span>&#160; iv_size);</div>
<div class="line"><a name="l00071"></a><span class="lineno"> 71</span>&#160; sample_data[kWebMSignalByteSize + kWebMIvSize] =</div>
<div class="line"><a name="l00072"></a><span class="lineno"> 72</span>&#160; <span class="keyword">static_cast&lt;</span>uint8_t<span class="keyword">&gt;</span>(num_partitions);</div>
<div class="line"><a name="l00073"></a><span class="lineno"> 73</span>&#160;</div>
<div class="line"><a name="l00074"></a><span class="lineno"> 74</span>&#160; BufferWriter offsets_buffer;</div>
<div class="line"><a name="l00075"></a><span class="lineno"> 75</span>&#160; uint32_t partition_offset = 0;</div>
<div class="line"><a name="l00076"></a><span class="lineno"> 76</span>&#160; <span class="keywordflow">for</span> (<span class="keywordtype">size_t</span> i = 0; i &lt; subsamples.size() - 1; ++i) {</div>
<div class="line"><a name="l00077"></a><span class="lineno"> 77</span>&#160; partition_offset += subsamples[i].clear_bytes;</div>
<div class="line"><a name="l00078"></a><span class="lineno"> 78</span>&#160; offsets_buffer.AppendInt(partition_offset);</div>
<div class="line"><a name="l00079"></a><span class="lineno"> 79</span>&#160; partition_offset += subsamples[i].cipher_bytes;</div>
<div class="line"><a name="l00080"></a><span class="lineno"> 80</span>&#160; offsets_buffer.AppendInt(partition_offset);</div>
<div class="line"><a name="l00081"></a><span class="lineno"> 81</span>&#160; }</div>
<div class="line"><a name="l00082"></a><span class="lineno"> 82</span>&#160; <span class="comment">// Add another partition between the clear bytes and cipher bytes if</span></div>
<div class="line"><a name="l00083"></a><span class="lineno"> 83</span>&#160; <span class="comment">// cipher bytes is not zero.</span></div>
<div class="line"><a name="l00084"></a><span class="lineno"> 84</span>&#160; <span class="keywordflow">if</span> (subsamples.back().cipher_bytes != 0) {</div>
<div class="line"><a name="l00085"></a><span class="lineno"> 85</span>&#160; partition_offset += subsamples.back().clear_bytes;</div>
<div class="line"><a name="l00086"></a><span class="lineno"> 86</span>&#160; offsets_buffer.AppendInt(partition_offset);</div>
<div class="line"><a name="l00087"></a><span class="lineno"> 87</span>&#160; }</div>
<div class="line"><a name="l00088"></a><span class="lineno"> 88</span>&#160; DCHECK_EQ(num_partitions * kWebMPartitionOffsetSize,</div>
<div class="line"><a name="l00089"></a><span class="lineno"> 89</span>&#160; offsets_buffer.Size());</div>
<div class="line"><a name="l00090"></a><span class="lineno"> 90</span>&#160; memcpy(sample_data + kWebMSignalByteSize + kWebMIvSize +</div>
<div class="line"><a name="l00091"></a><span class="lineno"> 91</span>&#160; kWebMNumPartitionsSize,</div>
<div class="line"><a name="l00092"></a><span class="lineno"> 92</span>&#160; offsets_buffer.Buffer(), offsets_buffer.Size());</div>
<div class="line"><a name="l00093"></a><span class="lineno"> 93</span>&#160; } <span class="keywordflow">else</span> {</div>
<div class="line"><a name="l00094"></a><span class="lineno"> 94</span>&#160; <span class="comment">// Use whole-frame encryption: | signal_byte(1) | iv | enc_data |</span></div>
<div class="line"><a name="l00095"></a><span class="lineno"> 95</span>&#160; sample-&gt;resize_data(sample_size + iv_size + kWebMSignalByteSize);</div>
<div class="line"><a name="l00096"></a><span class="lineno"> 96</span>&#160; uint8_t* sample_data = sample-&gt;writable_data();</div>
<div class="line"><a name="l00097"></a><span class="lineno"> 97</span>&#160;</div>
<div class="line"><a name="l00098"></a><span class="lineno"> 98</span>&#160; <span class="comment">// First move the sample data to after the IV; then write the IV and</span></div>
<div class="line"><a name="l00099"></a><span class="lineno"> 99</span>&#160; <span class="comment">// signal byte.</span></div>
<div class="line"><a name="l00100"></a><span class="lineno"> 100</span>&#160; memmove(sample_data + iv_size + kWebMSignalByteSize, sample_data,</div>
<div class="line"><a name="l00101"></a><span class="lineno"> 101</span>&#160; sample_size);</div>
<div class="line"><a name="l00102"></a><span class="lineno"> 102</span>&#160; sample_data[0] = kWebMEncryptedSignal;</div>
<div class="line"><a name="l00103"></a><span class="lineno"> 103</span>&#160; memcpy(sample_data + 1, decrypt_config-&gt;iv().data(), iv_size);</div>
<div class="line"><a name="l00104"></a><span class="lineno"> 104</span>&#160; }</div>
<div class="line"><a name="l00105"></a><span class="lineno"> 105</span>&#160; } <span class="keywordflow">else</span> {</div>
<div class="line"><a name="l00106"></a><span class="lineno"> 106</span>&#160; <span class="comment">// Clear sample: | signal_byte(0) | data |</span></div>
<div class="line"><a name="l00107"></a><span class="lineno"> 107</span>&#160; sample-&gt;resize_data(sample_size + 1);</div>
<div class="line"><a name="l00108"></a><span class="lineno"> 108</span>&#160; uint8_t* sample_data = sample-&gt;writable_data();</div>
<div class="line"><a name="l00109"></a><span class="lineno"> 109</span>&#160; memmove(sample_data + 1, sample_data, sample_size);</div>
<div class="line"><a name="l00110"></a><span class="lineno"> 110</span>&#160; sample_data[0] = 0x00;</div>
<div class="line"><a name="l00111"></a><span class="lineno"> 111</span>&#160; }</div>
<div class="line"><a name="l00112"></a><span class="lineno"> 112</span>&#160;}</div>
<div class="line"><a name="l00113"></a><span class="lineno"> 113</span>&#160;</div>
<div class="line"><a name="l00114"></a><span class="lineno"> 114</span>&#160;} <span class="comment">// namespace webm</span></div>
<div class="line"><a name="l00115"></a><span class="lineno"> 115</span>&#160;} <span class="comment">// namespace media</span></div>
<div class="line"><a name="l00116"></a><span class="lineno"> 116</span>&#160;} <span class="comment">// namespace shaka</span></div>
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