feat: Port AES and RSA crypto to mbedtls

packager/macros.h

@@ -32,4 +32,7 @@
 /// You can use the insertion operator to add specific logs to this.
 #define NOTIMPLEMENTED() LOG(ERROR) << "NOTIMPLEMENTED: "
 
+/// AES block size in bytes, regardless of key size.
+#define AES_BLOCK_SIZE 16
+
 #endif  // PACKAGER_MACROS_H_

packager/media/CMakeLists.txt

@@ -5,4 +5,5 @@
 # https://developers.google.com/open-source/licenses/bsd
 
 # Subdirectories with their own CMakeLists.txt, all of whose targets are built.
+add_subdirectory(base)
 add_subdirectory(test)

packager/media/base/CMakeLists.txt

@@ -0,0 +1,98 @@
+# Copyright 2022 Google LLC. All rights reserved.
+#
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file or at
+# https://developers.google.com/open-source/licenses/bsd
+
+# TODO: Add widevine_protos
+
+add_library(media_base STATIC
+    # TODO: finish media_base
+    aes_cryptor.cc
+    aes_decryptor.cc
+    aes_encryptor.cc
+    aes_pattern_cryptor.cc
+    #audio_stream_info.cc
+    #audio_timestamp_helper.cc
+    #bit_reader.cc
+    #bit_writer.cc
+    #buffer_reader.cc
+    #buffer_writer.cc
+    #byte_queue.cc
+    #cc_stream_filter.cc
+    #closure_thread.cc
+    #common_pssh_generator.cc
+    #container_names.cc
+    #decrypt_config.cc
+    #decryptor_source.cc
+    #http_key_fetcher.cc
+    #id3_tag.cc
+    #key_fetcher.cc
+    #key_source.cc
+    #language_utils.cc
+    #media_handler.cc
+    #media_sample.cc
+    #muxer.cc
+    #muxer_options.cc
+    #muxer_util.cc
+    #network_util.cc
+    #offset_byte_queue.cc
+    #playready_key_source.cc
+    #playready_pssh_generator.cc
+    #protection_system_specific_info.cc
+    #proto_json_util.cc
+    #pssh_generator.cc
+    #pssh_generator_util.cc
+    #raw_key_source.cc
+    #request_signer.cc
+    rsa_key.cc
+    #stream_info.cc
+    #text_muxer.cc
+    #text_sample.cc
+    #text_stream_info.cc
+    #text_track_config.cc
+    #video_stream_info.cc
+    #video_util.cc
+    #widevine_key_source.cc
+    #widevine_pssh_generator.cc
+)
+
+target_link_libraries(media_base
+    absl::base
+    absl::strings
+    glog
+    mbedtls)
+
+# TODO: lib media_handler_test_base
+
+add_executable(media_base_unittest
+    # TODO: finish media_base_unittest
+    aes_cryptor_unittest.cc
+    aes_pattern_cryptor_unittest.cc
+    #audio_timestamp_helper_unittest.cc
+    #bit_reader_unittest.cc
+    #bit_writer_unittest.cc
+    #buffer_writer_unittest.cc
+    #closure_thread_unittest.cc
+    #container_names_unittest.cc
+    #decryptor_source_unittest.cc
+    #http_key_fetcher_unittest.cc
+    #id3_tag_unittest.cc
+    #muxer_util_unittest.cc
+    #offset_byte_queue_unittest.cc
+    #producer_consumer_queue_unittest.cc
+    #protection_system_specific_info_unittest.cc
+    #pssh_generator_unittest.cc
+    #raw_key_source_unittest.cc
+    rsa_key_unittest.cc
+    test/rsa_test_data.cc
+    #video_util_unittest.cc
+    #widevine_key_source_unittest.cc
+)
+target_link_libraries(media_base_unittest
+    media_base
+    gmock
+    gtest
+    gtest_main
+    test_data_util)
+add_test(NAME media_base_unittest COMMAND media_base_unittest)

packager/media/base/aes_cryptor.cc

@@ -6,15 +6,11 @@
 
 #include "packager/media/base/aes_cryptor.h"
 
-#include <openssl/aes.h>
-#include <openssl/crypto.h>
-#include <openssl/err.h>
-#include <openssl/rand.h>
-
 #include <string>
 #include <vector>
 
-#include "packager/base/logging.h"
+#include "glog/logging.h"
+#include "mbedtls/entropy.h"
 
 namespace {
 
@@ -30,20 +26,21 @@ namespace shaka {
 namespace media {
 
 AesCryptor::AesCryptor(ConstantIvFlag constant_iv_flag)
-    : aes_key_(new AES_KEY),
-      constant_iv_flag_(constant_iv_flag),
-      num_crypt_bytes_(0) {
-  CRYPTO_library_init();
+    : constant_iv_flag_(constant_iv_flag), num_crypt_bytes_(0) {
+  mbedtls_cipher_init(&cipher_ctx_);
 }
 
-AesCryptor::~AesCryptor() {}
+AesCryptor::~AesCryptor() {
+  mbedtls_cipher_free(&cipher_ctx_);
+}
 
 bool AesCryptor::Crypt(const std::vector<uint8_t>& text,
                        std::vector<uint8_t>* crypt_text) {
   // Save text size to make it work for in-place conversion, since the
   // next statement will update the text size.
   const size_t text_size = text.size();
-  crypt_text->resize(text_size + NumPaddingBytes(text_size));
+  // mbedtls requires an extra block's worth of output buffer available.
+  crypt_text->resize(text_size + NumPaddingBytes(text_size) + AES_BLOCK_SIZE);
   size_t crypt_text_size = crypt_text->size();
   if (!Crypt(text.data(), text_size, crypt_text->data(), &crypt_text_size)) {
     return false;
@@ -57,7 +54,8 @@ bool AesCryptor::Crypt(const std::string& text, std::string* crypt_text) {
   // Save text size to make it work for in-place conversion, since the
   // next statement will update the text size.
   const size_t text_size = text.size();
-  crypt_text->resize(text_size + NumPaddingBytes(text_size));
+  // mbedtls requires an extra block's worth of output buffer available.
+  crypt_text->resize(text_size + NumPaddingBytes(text_size) + AES_BLOCK_SIZE);
   size_t crypt_text_size = crypt_text->size();
   if (!Crypt(reinterpret_cast<const uint8_t*>(text.data()), text_size,
              reinterpret_cast<uint8_t*>(&(*crypt_text)[0]), &crypt_text_size))
@@ -98,7 +96,7 @@ void AesCryptor::UpdateIv() {
     increment = (num_crypt_bytes_ + AES_BLOCK_SIZE - 1) / AES_BLOCK_SIZE;
   }
 
-  for (int i = iv_.size() - 1; increment > 0 && i >= 0; --i) {
+  for (int64_t i = iv_.size() - 1; increment > 0 && i >= 0; --i) {
     increment += iv_[i];
     iv_[i] = increment & 0xFF;
     increment >>= 8;
@@ -118,18 +116,71 @@ bool AesCryptor::GenerateRandomIv(FourCC protection_scheme,
           ? 8
           : 16;
   iv->resize(iv_size);
-  if (RAND_bytes(iv->data(), iv_size) != 1) {
-    LOG(ERROR) << "RAND_bytes failed with error: "
-               << ERR_error_string(ERR_get_error(), NULL);
+
+  mbedtls_entropy_context entropy_ctx;
+  mbedtls_entropy_init(&entropy_ctx);
+  int rv = mbedtls_entropy_func(&entropy_ctx, iv->data(), iv_size);
+  mbedtls_entropy_free(&entropy_ctx);
+
+  if (rv != 0) {
+    LOG(ERROR) << "mbedtls_entropy_func failed with: " << rv;
     return false;
   }
   return true;
 }
 
 size_t AesCryptor::NumPaddingBytes(size_t size) const {
   // No padding by default.
+  UNUSED(size);
   return 0;
 }
 
+bool AesCryptor::SetupCipher(size_t key_size, CipherMode mode) {
+  mbedtls_cipher_type_t type;
+
+  // AES defines three key sizes: 128, 192 and 256 bits.
+  // NOTE: Because we use ECB mode in the CTR cryptors, this returns ECB
+  // instead of CTR.  Counters and block offsets are managed internally.
+  switch (key_size) {
+    case 16:
+      type = mode == kCtrMode ? MBEDTLS_CIPHER_AES_128_ECB
+                              : MBEDTLS_CIPHER_AES_128_CBC;
+      break;
+    case 24:
+      type = mode == kCtrMode ? MBEDTLS_CIPHER_AES_192_ECB
+                              : MBEDTLS_CIPHER_AES_192_CBC;
+      break;
+    case 32:
+      type = mode == kCtrMode ? MBEDTLS_CIPHER_AES_256_ECB
+                              : MBEDTLS_CIPHER_AES_256_CBC;
+      break;
+    default:
+      LOG(ERROR) << "Invalid AES key size: " << key_size;
+      return false;
+  }
+
+  const mbedtls_cipher_info_t* cipher_info =
+      mbedtls_cipher_info_from_type(type);
+  CHECK(cipher_info);
+
+  if (mbedtls_cipher_setup(&cipher_ctx_, cipher_info) != 0) {
+    LOG(ERROR) << "Cipher setup failed";
+    return false;
+  }
+
+  // Padding mode only applies to CBC.
+  if (mode == kCbcMode) {
+    // We handle padding ourselves.  Don't let mbedtls mess with it.
+    mbedtls_cipher_padding_t cipher_padding = MBEDTLS_PADDING_NONE;
+
+    if (mbedtls_cipher_set_padding_mode(&cipher_ctx_, cipher_padding) != 0) {
+      LOG(ERROR) << "Failed to set CBC padding mode";
+      return false;
+    }
+  }
+
+  return true;
+}
+
 }  // namespace media
 }  // namespace shaka

packager/media/base/aes_cryptor.h

@@ -11,12 +11,10 @@
 #include <string>
 #include <vector>
 
-#include "packager/base/macros.h"
+#include "mbedtls/cipher.h"
+#include "packager/macros.h"
 #include "packager/media/base/fourccs.h"
 
-struct aes_key_st;
-typedef struct aes_key_st AES_KEY;
-
 namespace shaka {
 namespace media {
 
@@ -92,8 +90,15 @@ class AesCryptor {
                                std::vector<uint8_t>* iv);
 
  protected:
-  const AES_KEY* aes_key() const { return aes_key_.get(); }
-  AES_KEY* mutable_aes_key() { return aes_key_.get(); }
+  enum CipherMode {
+    kCtrMode,
+    kCbcMode,
+  };
+
+  // mbedTLS cipher context.
+  mbedtls_cipher_context_t cipher_ctx_;
+
+  bool SetupCipher(size_t key_size, CipherMode mode);
 
  private:
   // Internal implementation of crypt function.
@@ -119,9 +124,6 @@ class AesCryptor {
   // Note: No paddings should be needed except for pkcs5-cbc encryptor.
   virtual size_t NumPaddingBytes(size_t size) const;
 
-  // Openssl AES_KEY.
-  std::unique_ptr<AES_KEY> aes_key_;
-
   // Indicates whether a constant iv is used. Internal iv will be reset to
   // |iv_| before calling Crypt if that is the case.
   const ConstantIvFlag constant_iv_flag_;