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<div class="fragment"><div class="line"><a name="l00001"></a><span class="lineno"> 1</span>&#160;<span class="comment">// Copyright 2016 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/base/decryptor_source.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/base/logging.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/aes_decryptor.h&quot;</span></div>
<div class="line"><a name="l00011"></a><span class="lineno"> 11</span>&#160;<span class="preprocessor">#include &quot;packager/media/base/aes_pattern_cryptor.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;</div>
<div class="line"><a name="l00016"></a><span class="lineno"> 16</span>&#160;DecryptorSource::DecryptorSource(KeySource* key_source)</div>
<div class="line"><a name="l00017"></a><span class="lineno"> 17</span>&#160; : key_source_(key_source) {</div>
<div class="line"><a name="l00018"></a><span class="lineno"> 18</span>&#160; CHECK(key_source);</div>
<div class="line"><a name="l00019"></a><span class="lineno"> 19</span>&#160;}</div>
<div class="line"><a name="l00020"></a><span class="lineno"> 20</span>&#160;DecryptorSource::~DecryptorSource() {}</div>
<div class="line"><a name="l00021"></a><span class="lineno"> 21</span>&#160;</div>
<div class="line"><a name="l00022"></a><span class="lineno"> 22</span>&#160;<span class="keywordtype">bool</span> DecryptorSource::DecryptSampleBuffer(<span class="keyword">const</span> DecryptConfig* decrypt_config,</div>
<div class="line"><a name="l00023"></a><span class="lineno"> 23</span>&#160; uint8_t* buffer,</div>
<div class="line"><a name="l00024"></a><span class="lineno"> 24</span>&#160; <span class="keywordtype">size_t</span> buffer_size) {</div>
<div class="line"><a name="l00025"></a><span class="lineno"> 25</span>&#160; DCHECK(decrypt_config);</div>
<div class="line"><a name="l00026"></a><span class="lineno"> 26</span>&#160; DCHECK(buffer);</div>
<div class="line"><a name="l00027"></a><span class="lineno"> 27</span>&#160;</div>
<div class="line"><a name="l00028"></a><span class="lineno"> 28</span>&#160; <span class="comment">// Get the decryptor object.</span></div>
<div class="line"><a name="l00029"></a><span class="lineno"> 29</span>&#160; AesCryptor* decryptor = <span class="keyword">nullptr</span>;</div>
<div class="line"><a name="l00030"></a><span class="lineno"> 30</span>&#160; <span class="keyword">auto</span> found = decryptor_map_.find(decrypt_config-&gt;key_id());</div>
<div class="line"><a name="l00031"></a><span class="lineno"> 31</span>&#160; <span class="keywordflow">if</span> (found == decryptor_map_.end()) {</div>
<div class="line"><a name="l00032"></a><span class="lineno"> 32</span>&#160; <span class="comment">// Create new AesDecryptor based on decryption mode.</span></div>
<div class="line"><a name="l00033"></a><span class="lineno"> 33</span>&#160; EncryptionKey key;</div>
<div class="line"><a name="l00034"></a><span class="lineno"> 34</span>&#160; Status status(key_source_-&gt;<a class="code" href="../../d1/d1f/classshaka_1_1media_1_1KeySource.html#a994eb66cf09d8b08fd1c964f6afd3ab3">GetKey</a>(decrypt_config-&gt;key_id(), &amp;key));</div>
<div class="line"><a name="l00035"></a><span class="lineno"> 35</span>&#160; <span class="keywordflow">if</span> (!status.ok()) {</div>
<div class="line"><a name="l00036"></a><span class="lineno"> 36</span>&#160; LOG(ERROR) &lt;&lt; <span class="stringliteral">&quot;Error retrieving decryption key: &quot;</span> &lt;&lt; status;</div>
<div class="line"><a name="l00037"></a><span class="lineno"> 37</span>&#160; <span class="keywordflow">return</span> <span class="keyword">false</span>;</div>
<div class="line"><a name="l00038"></a><span class="lineno"> 38</span>&#160; }</div>
<div class="line"><a name="l00039"></a><span class="lineno"> 39</span>&#160;</div>
<div class="line"><a name="l00040"></a><span class="lineno"> 40</span>&#160; std::unique_ptr&lt;AesCryptor&gt; aes_decryptor;</div>
<div class="line"><a name="l00041"></a><span class="lineno"> 41</span>&#160; <span class="keywordflow">switch</span> (decrypt_config-&gt;protection_scheme()) {</div>
<div class="line"><a name="l00042"></a><span class="lineno"> 42</span>&#160; <span class="keywordflow">case</span> FOURCC_cenc:</div>
<div class="line"><a name="l00043"></a><span class="lineno"> 43</span>&#160; aes_decryptor.reset(<span class="keyword">new</span> AesCtrDecryptor);</div>
<div class="line"><a name="l00044"></a><span class="lineno"> 44</span>&#160; <span class="keywordflow">break</span>;</div>
<div class="line"><a name="l00045"></a><span class="lineno"> 45</span>&#160; <span class="keywordflow">case</span> FOURCC_cbc1:</div>
<div class="line"><a name="l00046"></a><span class="lineno"> 46</span>&#160; aes_decryptor.reset(<span class="keyword">new</span> AesCbcDecryptor(kNoPadding));</div>
<div class="line"><a name="l00047"></a><span class="lineno"> 47</span>&#160; <span class="keywordflow">break</span>;</div>
<div class="line"><a name="l00048"></a><span class="lineno"> 48</span>&#160; <span class="keywordflow">case</span> FOURCC_cens:</div>
<div class="line"><a name="l00049"></a><span class="lineno"> 49</span>&#160; aes_decryptor.reset(<span class="keyword">new</span> AesPatternCryptor(</div>
<div class="line"><a name="l00050"></a><span class="lineno"> 50</span>&#160; decrypt_config-&gt;crypt_byte_block(),</div>
<div class="line"><a name="l00051"></a><span class="lineno"> 51</span>&#160; decrypt_config-&gt;skip_byte_block(),</div>
<div class="line"><a name="l00052"></a><span class="lineno"> 52</span>&#160; <a class="code" href="../../d3/dfe/classshaka_1_1media_1_1AesPatternCryptor.html#a54fd35d7782d3b4948c7eb68387711f0a76b19d202e22b2b0f661f933b47b3b16">AesPatternCryptor::kEncryptIfCryptByteBlockRemaining</a>,</div>
<div class="line"><a name="l00053"></a><span class="lineno"> 53</span>&#160; AesCryptor::kDontUseConstantIv,</div>
<div class="line"><a name="l00054"></a><span class="lineno"> 54</span>&#160; std::unique_ptr&lt;AesCryptor&gt;(<span class="keyword">new</span> AesCtrDecryptor())));</div>
<div class="line"><a name="l00055"></a><span class="lineno"> 55</span>&#160; <span class="keywordflow">break</span>;</div>
<div class="line"><a name="l00056"></a><span class="lineno"> 56</span>&#160; <span class="keywordflow">case</span> FOURCC_cbcs:</div>
<div class="line"><a name="l00057"></a><span class="lineno"> 57</span>&#160; aes_decryptor.reset(<span class="keyword">new</span> AesPatternCryptor(</div>
<div class="line"><a name="l00058"></a><span class="lineno"> 58</span>&#160; decrypt_config-&gt;crypt_byte_block(),</div>
<div class="line"><a name="l00059"></a><span class="lineno"> 59</span>&#160; decrypt_config-&gt;skip_byte_block(),</div>
<div class="line"><a name="l00060"></a><span class="lineno"> 60</span>&#160; <a class="code" href="../../d3/dfe/classshaka_1_1media_1_1AesPatternCryptor.html#a54fd35d7782d3b4948c7eb68387711f0a76b19d202e22b2b0f661f933b47b3b16">AesPatternCryptor::kEncryptIfCryptByteBlockRemaining</a>,</div>
<div class="line"><a name="l00061"></a><span class="lineno"> 61</span>&#160; AesCryptor::kUseConstantIv,</div>
<div class="line"><a name="l00062"></a><span class="lineno"> 62</span>&#160; std::unique_ptr&lt;AesCryptor&gt;(<span class="keyword">new</span> AesCbcDecryptor(kNoPadding))));</div>
<div class="line"><a name="l00063"></a><span class="lineno"> 63</span>&#160; <span class="keywordflow">break</span>;</div>
<div class="line"><a name="l00064"></a><span class="lineno"> 64</span>&#160; <span class="keywordflow">default</span>:</div>
<div class="line"><a name="l00065"></a><span class="lineno"> 65</span>&#160; LOG(ERROR) &lt;&lt; <span class="stringliteral">&quot;Unsupported protection scheme: &quot;</span></div>
<div class="line"><a name="l00066"></a><span class="lineno"> 66</span>&#160; &lt;&lt; decrypt_config-&gt;protection_scheme();</div>
<div class="line"><a name="l00067"></a><span class="lineno"> 67</span>&#160; <span class="keywordflow">return</span> <span class="keyword">false</span>;</div>
<div class="line"><a name="l00068"></a><span class="lineno"> 68</span>&#160; }</div>
<div class="line"><a name="l00069"></a><span class="lineno"> 69</span>&#160;</div>
<div class="line"><a name="l00070"></a><span class="lineno"> 70</span>&#160; <span class="keywordflow">if</span> (!aes_decryptor-&gt;InitializeWithIv(key.key, decrypt_config-&gt;iv())) {</div>
<div class="line"><a name="l00071"></a><span class="lineno"> 71</span>&#160; LOG(ERROR) &lt;&lt; <span class="stringliteral">&quot;Failed to initialize AesDecryptor for decryption.&quot;</span>;</div>
<div class="line"><a name="l00072"></a><span class="lineno"> 72</span>&#160; <span class="keywordflow">return</span> <span class="keyword">false</span>;</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; decryptor = aes_decryptor.get();</div>
<div class="line"><a name="l00075"></a><span class="lineno"> 75</span>&#160; decryptor_map_[decrypt_config-&gt;key_id()] = std::move(aes_decryptor);</div>
<div class="line"><a name="l00076"></a><span class="lineno"> 76</span>&#160; } <span class="keywordflow">else</span> {</div>
<div class="line"><a name="l00077"></a><span class="lineno"> 77</span>&#160; decryptor = found-&gt;second.get();</div>
<div class="line"><a name="l00078"></a><span class="lineno"> 78</span>&#160; }</div>
<div class="line"><a name="l00079"></a><span class="lineno"> 79</span>&#160; <span class="keywordflow">if</span> (!decryptor-&gt;SetIv(decrypt_config-&gt;iv())) {</div>
<div class="line"><a name="l00080"></a><span class="lineno"> 80</span>&#160; LOG(ERROR) &lt;&lt; <span class="stringliteral">&quot;Invalid initialization vector.&quot;</span>;</div>
<div class="line"><a name="l00081"></a><span class="lineno"> 81</span>&#160; <span class="keywordflow">return</span> <span class="keyword">false</span>;</div>
<div class="line"><a name="l00082"></a><span class="lineno"> 82</span>&#160; }</div>
<div class="line"><a name="l00083"></a><span class="lineno"> 83</span>&#160;</div>
<div class="line"><a name="l00084"></a><span class="lineno"> 84</span>&#160; <span class="keywordflow">if</span> (decrypt_config-&gt;subsamples().empty()) {</div>
<div class="line"><a name="l00085"></a><span class="lineno"> 85</span>&#160; <span class="comment">// Sample not encrypted using subsample encryption. Decrypt whole.</span></div>
<div class="line"><a name="l00086"></a><span class="lineno"> 86</span>&#160; <span class="keywordflow">if</span> (!decryptor-&gt;Crypt(buffer, buffer_size, buffer)) {</div>
<div class="line"><a name="l00087"></a><span class="lineno"> 87</span>&#160; LOG(ERROR) &lt;&lt; <span class="stringliteral">&quot;Error during bulk sample decryption.&quot;</span>;</div>
<div class="line"><a name="l00088"></a><span class="lineno"> 88</span>&#160; <span class="keywordflow">return</span> <span class="keyword">false</span>;</div>
<div class="line"><a name="l00089"></a><span class="lineno"> 89</span>&#160; }</div>
<div class="line"><a name="l00090"></a><span class="lineno"> 90</span>&#160; <span class="keywordflow">return</span> <span class="keyword">true</span>;</div>
<div class="line"><a name="l00091"></a><span class="lineno"> 91</span>&#160; }</div>
<div class="line"><a name="l00092"></a><span class="lineno"> 92</span>&#160;</div>
<div class="line"><a name="l00093"></a><span class="lineno"> 93</span>&#160; <span class="comment">// Subsample decryption.</span></div>
<div class="line"><a name="l00094"></a><span class="lineno"> 94</span>&#160; <span class="keyword">const</span> std::vector&lt;SubsampleEntry&gt;&amp; subsamples = decrypt_config-&gt;subsamples();</div>
<div class="line"><a name="l00095"></a><span class="lineno"> 95</span>&#160; uint8_t* current_ptr = buffer;</div>
<div class="line"><a name="l00096"></a><span class="lineno"> 96</span>&#160; <span class="keyword">const</span> uint8_t* <span class="keyword">const</span> buffer_end = buffer + buffer_size;</div>
<div class="line"><a name="l00097"></a><span class="lineno"> 97</span>&#160; <span class="keywordflow">for</span> (<span class="keyword">const</span> <span class="keyword">auto</span>&amp; subsample : subsamples) {</div>
<div class="line"><a name="l00098"></a><span class="lineno"> 98</span>&#160; <span class="keywordflow">if</span> ((current_ptr + subsample.clear_bytes + subsample.cipher_bytes) &gt;</div>
<div class="line"><a name="l00099"></a><span class="lineno"> 99</span>&#160; buffer_end) {</div>
<div class="line"><a name="l00100"></a><span class="lineno"> 100</span>&#160; LOG(ERROR) &lt;&lt; <span class="stringliteral">&quot;Subsamples overflow sample buffer.&quot;</span>;</div>
<div class="line"><a name="l00101"></a><span class="lineno"> 101</span>&#160; <span class="keywordflow">return</span> <span class="keyword">false</span>;</div>
<div class="line"><a name="l00102"></a><span class="lineno"> 102</span>&#160; }</div>
<div class="line"><a name="l00103"></a><span class="lineno"> 103</span>&#160; current_ptr += subsample.clear_bytes;</div>
<div class="line"><a name="l00104"></a><span class="lineno"> 104</span>&#160; <span class="keywordflow">if</span> (!decryptor-&gt;Crypt(current_ptr, subsample.cipher_bytes, current_ptr)) {</div>
<div class="line"><a name="l00105"></a><span class="lineno"> 105</span>&#160; LOG(ERROR) &lt;&lt; <span class="stringliteral">&quot;Error decrypting subsample buffer.&quot;</span>;</div>
<div class="line"><a name="l00106"></a><span class="lineno"> 106</span>&#160; <span class="keywordflow">return</span> <span class="keyword">false</span>;</div>
<div class="line"><a name="l00107"></a><span class="lineno"> 107</span>&#160; }</div>
<div class="line"><a name="l00108"></a><span class="lineno"> 108</span>&#160; current_ptr += subsample.cipher_bytes;</div>
<div class="line"><a name="l00109"></a><span class="lineno"> 109</span>&#160; }</div>
<div class="line"><a name="l00110"></a><span class="lineno"> 110</span>&#160; <span class="keywordflow">return</span> <span class="keyword">true</span>;</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;} <span class="comment">// namespace media</span></div>
<div class="line"><a name="l00114"></a><span class="lineno"> 114</span>&#160;} <span class="comment">// namespace shaka</span></div>
<div class="ttc" id="classshaka_1_1media_1_1AesPatternCryptor_html_a54fd35d7782d3b4948c7eb68387711f0a76b19d202e22b2b0f661f933b47b3b16"><div class="ttname"><a href="../../d3/dfe/classshaka_1_1media_1_1AesPatternCryptor.html#a54fd35d7782d3b4948c7eb68387711f0a76b19d202e22b2b0f661f933b47b3b16">shaka::media::AesPatternCryptor::kEncryptIfCryptByteBlockRemaining</a></div><div class="ttdef"><b>Definition:</b> <a href="../../d6/d09/aes__pattern__cryptor_8h_source.html#l00026">aes_pattern_cryptor.h:26</a></div></div>
<div class="ttc" id="classshaka_1_1media_1_1KeySource_html_a994eb66cf09d8b08fd1c964f6afd3ab3"><div class="ttname"><a href="../../d1/d1f/classshaka_1_1media_1_1KeySource.html#a994eb66cf09d8b08fd1c964f6afd3ab3">shaka::media::KeySource::GetKey</a></div><div class="ttdeci">virtual Status GetKey(TrackType track_type, EncryptionKey *key)=0</div></div>
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