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-rw-r--r--media/base/decrypt_config.cc3
-rw-r--r--media/base/decrypt_config.h4
-rw-r--r--media/crypto/aes_decryptor.cc29
-rw-r--r--media/crypto/aes_decryptor_unittest.cc128
-rw-r--r--media/webm/webm_cluster_parser.cc61
-rw-r--r--media/webm/webm_constants.h1
6 files changed, 85 insertions, 141 deletions
diff --git a/media/base/decrypt_config.cc b/media/base/decrypt_config.cc
index 3142751..c499c92 100644
--- a/media/base/decrypt_config.cc
+++ b/media/base/decrypt_config.cc
@@ -19,8 +19,7 @@ DecryptConfig::DecryptConfig(const std::string& key_id,
data_offset_(data_offset),
subsamples_(subsamples) {
CHECK_GT(key_id.size(), 0u);
- CHECK(iv.size() == static_cast<size_t>(DecryptConfig::kDecryptionKeySize) ||
- iv.empty());
+ CHECK_EQ(iv.size(), static_cast<size_t>(DecryptConfig::kDecryptionKeySize));
CHECK_GE(data_offset, 0);
}
diff --git a/media/base/decrypt_config.h b/media/base/decrypt_config.h
index 669aa36..d8ad224 100644
--- a/media/base/decrypt_config.h
+++ b/media/base/decrypt_config.h
@@ -36,9 +36,7 @@ class MEDIA_EXPORT DecryptConfig {
// |key_id| is the ID that references the decryption key for this sample.
// |iv| is the initialization vector defined by the encrypted format.
- // Currently |iv| must be 16 bytes as defined by WebM and ISO. Or must be
- // empty which signals to perform the integrity check on an unencrypted
- // frame as defined WebM.
+ // Currently |iv_size| must be 16 bytes as defined by WebM and ISO.
// |checksum| is the hash value of the encrypted buffer. |checksum| is
// defined by the encrypted format and may be NULL.
// |data_offset| is the amount of data that should be discarded from the
diff --git a/media/crypto/aes_decryptor.cc b/media/crypto/aes_decryptor.cc
index 27272c6..e585800 100644
--- a/media/crypto/aes_decryptor.cc
+++ b/media/crypto/aes_decryptor.cc
@@ -285,24 +285,17 @@ void AesDecryptor::Decrypt(const scoped_refptr<DecoderBuffer>& encrypted,
return;
}
- scoped_refptr<DecoderBuffer> decrypted;
- // An empty iv string signals that the frame is unencrypted.
- if (encrypted->GetDecryptConfig()->iv().empty()) {
- int data_offset = encrypted->GetDecryptConfig()->data_offset();
- decrypted = DecoderBuffer::CopyFrom(encrypted->GetData() + data_offset,
- encrypted->GetDataSize() - data_offset);
- } else {
- // TODO(strobe): Currently, presence of checksum is used to indicate the use
- // of normal or WebM decryption keys. Consider a more explicit signaling
- // mechanism and the removal of the webm_decryption_key member.
- crypto::SymmetricKey* decryption_key = (checksum_size > 0) ?
- key->webm_decryption_key() : key->decryption_key();
- decrypted = DecryptData(*encrypted, decryption_key);
- if (!decrypted) {
- DVLOG(1) << "Decryption failed.";
- decrypt_cb.Run(kError, NULL);
- return;
- }
+ // TODO(strobe): Currently, presence of checksum is used to indicate the use
+ // of normal or WebM decryption keys. Consider a more explicit signaling
+ // mechanism and the removal of the webm_decryption_key member.
+ crypto::SymmetricKey* decryption_key = (checksum_size > 0) ?
+ key->webm_decryption_key() : key->decryption_key();
+ scoped_refptr<DecoderBuffer> decrypted =
+ DecryptData(*encrypted, decryption_key);
+ if (!decrypted) {
+ DVLOG(1) << "Decryption failed.";
+ decrypt_cb.Run(kError, NULL);
+ return;
}
decrypted->SetTimestamp(encrypted->GetTimestamp());
diff --git a/media/crypto/aes_decryptor_unittest.cc b/media/crypto/aes_decryptor_unittest.cc
index fd1704a..12df91a 100644
--- a/media/crypto/aes_decryptor_unittest.cc
+++ b/media/crypto/aes_decryptor_unittest.cc
@@ -41,8 +41,7 @@ struct WebmEncryptedData {
static const char kClearKeySystem[] = "org.w3.clearkey";
// Frames 0 & 1 are encrypted with the same key. Frame 2 is encrypted with a
-// different key. Frame 3 has the same HMAC key as frame 2, but frame 3 is
-// unencrypted.
+// different key.
const WebmEncryptedData kWebmEncryptedFrames[] = {
{
// plaintext
@@ -51,18 +50,18 @@ const WebmEncryptedData kWebmEncryptedFrames[] = {
{ 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
0x10, 0x11, 0x12, 0x13
- }, 20,
+ }, 20,
// key
{ 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x1b,
0x1c, 0x1d, 0x1e, 0x1f, 0x20, 0x21, 0x22, 0x23
- }, 16,
+ }, 16,
// encrypted_data
- { 0x3c, 0x4e, 0xb8, 0xd9, 0x5c, 0x20, 0x48, 0x18,
- 0x4f, 0x03, 0x74, 0xa1, 0x01, 0xff, 0xff, 0xff,
- 0xff, 0xff, 0xff, 0xff, 0xff, 0x99, 0xaa, 0xff,
- 0xb7, 0x74, 0x02, 0x4e, 0x1c, 0x75, 0x3d, 0xee,
- 0xcb, 0x64, 0xf7
- }, 35
+ { 0xfb, 0xe7, 0x1d, 0xbb, 0x4c, 0x23, 0xce, 0xba,
+ 0xcc, 0xf8, 0xda, 0xc0, 0xff, 0xff, 0xff, 0xff,
+ 0xff, 0xff, 0xff, 0xff, 0x99, 0xaa, 0xff, 0xb7,
+ 0x74, 0x02, 0x4e, 0x1c, 0x75, 0x3d, 0xee, 0xcb,
+ 0x64, 0xf7
+ }, 34
},
{
// plaintext
@@ -71,19 +70,19 @@ const WebmEncryptedData kWebmEncryptedFrames[] = {
{ 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
0x10, 0x11, 0x12, 0x13
- }, 20,
+ }, 20,
// key
{ 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x1b,
0x1c, 0x1d, 0x1e, 0x1f, 0x20, 0x21, 0x22, 0x23
- }, 16,
+ }, 16,
// encrypted_data
- { 0xe8, 0x4c, 0x51, 0x33, 0x14, 0x0d, 0xc7, 0x17,
- 0x32, 0x60, 0xc9, 0xd0, 0x01, 0x00, 0x00, 0x00,
- 0x00, 0x00, 0x00, 0x00, 0x00, 0xec, 0x8e, 0x87,
- 0x21, 0xd3, 0xb9, 0x1c, 0x61, 0xf6, 0x5a, 0x60,
- 0xaa, 0x07, 0x0e, 0x96, 0xd0, 0x54, 0x5d, 0x35,
- 0x9a, 0x4a, 0xd3
- }, 43
+ { 0x43, 0xe4, 0x78, 0x7a, 0x43, 0xe1, 0x49, 0xbb,
+ 0x44, 0x38, 0xdf, 0xfc, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0xec, 0x8e, 0x87, 0x21,
+ 0xd3, 0xb9, 0x1c, 0x61, 0xf6, 0x5a, 0x60, 0xaa,
+ 0x07, 0x0e, 0x96, 0xd0, 0x54, 0x5d, 0x35, 0x9a,
+ 0x4a, 0xd3
+ }, 42
},
{
// plaintext
@@ -91,37 +90,18 @@ const WebmEncryptedData kWebmEncryptedFrames[] = {
// key_id
{ 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b,
0x2c, 0x2d, 0x2e, 0x2f, 0x30
- }, 13,
+ }, 13,
// key
{ 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38,
0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f, 0x40
- }, 16,
+ }, 16,
// encrypted_data
- { 0x46, 0x93, 0x8c, 0x93, 0x48, 0xf9, 0xeb, 0x30,
- 0x74, 0x55, 0x6b, 0xf2, 0x01, 0x00, 0x00, 0x00,
- 0x00, 0x00, 0x00, 0x00, 0x01, 0x48, 0x5e, 0x4a,
- 0x41, 0x2a, 0x8b, 0xf4, 0xc6, 0x47, 0x54, 0x90,
- 0x34, 0xf4, 0x8b
- }, 35
- },
- {
- // plaintext
- "Changed Original data.", 22,
- // key_id
- { 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b,
- 0x2c, 0x2d, 0x2e, 0x2f, 0x30
- }, 13,
- // key
- { 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38,
- 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f, 0x40
- }, 16,
- // encrypted_data
- { 0xee, 0xd6, 0xf5, 0x64, 0x5f, 0xe0, 0x6a, 0xa2,
- 0x9e, 0xd6, 0xce, 0x34, 0x00, 0x43, 0x68, 0x61,
- 0x6e, 0x67, 0x65, 0x64, 0x20, 0x4f, 0x72, 0x69,
- 0x67, 0x69, 0x6e, 0x61, 0x6c, 0x20, 0x64, 0x61,
- 0x74, 0x61, 0x2e
- }, 35
+ { 0xd9, 0x43, 0x30, 0xfd, 0x82, 0x77, 0x62, 0x04,
+ 0x08, 0xc2, 0x48, 0x89, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x01, 0x48, 0x5e, 0x4a, 0x41,
+ 0x2a, 0x8b, 0xf4, 0xc6, 0x47, 0x54, 0x90, 0x34,
+ 0xf4, 0x8b
+ }, 34
}
};
@@ -212,18 +192,22 @@ static std::string GenerateCounterBlock(const uint8* iv, int iv_size) {
const int kDecryptionKeySize = 16;
CHECK_GT(iv_size, 0);
CHECK_LE(iv_size, kDecryptionKeySize);
+ char counter_block_data[kDecryptionKeySize];
- std::string counter_block(reinterpret_cast<const char*>(iv), iv_size);
- counter_block.append(kDecryptionKeySize - iv_size, 0);
- return counter_block;
+ // Set the IV.
+ memcpy(counter_block_data, iv, iv_size);
+
+ // Set block counter to all 0's.
+ memset(counter_block_data + iv_size, 0, kDecryptionKeySize - iv_size);
+
+ return std::string(counter_block_data, kDecryptionKeySize);
}
// Creates a WebM encrypted buffer that the demuxer would pass to the
// decryptor. |data| is the payload of a WebM encrypted Block. |key_id| is
// initialization data from the WebM file. Every encrypted Block has
-// an HMAC and a signal byte prepended to a frame. If the frame is encrypted
-// then an IV is prepended to the Block. Current encrypted WebM request for
-// comments specification is here
+// an HMAC and IV prepended to an encrypted frame. Current encrypted WebM
+// request for comments specification is here
// http://wiki.webmproject.org/encryption/webm-encryption-rfc
static scoped_refptr<DecoderBuffer> CreateWebMEncryptedBuffer(
const uint8* data, int data_size,
@@ -232,29 +216,17 @@ static scoped_refptr<DecoderBuffer> CreateWebMEncryptedBuffer(
data + kWebMHmacSize, data_size - kWebMHmacSize);
CHECK(encrypted_buffer);
- uint8 signal_byte = data[kWebMHmacSize];
- int data_offset = sizeof(signal_byte);
-
- // Setting the DecryptConfig object of the buffer while leaving the
- // initialization vector empty will tell the decryptor that the frame is
- // unencrypted but integrity should still be checked.
- std::string counter_block_str;
-
- if (signal_byte & kWebMFlagEncryptedFrame) {
- uint64 network_iv;
- memcpy(&network_iv, data + kWebMHmacSize + data_offset, sizeof(network_iv));
- const uint64 iv = base::NetToHost64(network_iv);
- counter_block_str =
- GenerateCounterBlock(reinterpret_cast<const uint8*>(&iv), sizeof(iv));
- data_offset += sizeof(iv);
- }
-
+ uint64 network_iv;
+ memcpy(&network_iv, data + kWebMHmacSize, sizeof(network_iv));
+ const uint64 iv = base::NetToHost64(network_iv);
+ std::string webm_iv =
+ GenerateCounterBlock(reinterpret_cast<const uint8*>(&iv), sizeof(iv));
encrypted_buffer->SetDecryptConfig(
scoped_ptr<DecryptConfig>(new DecryptConfig(
std::string(reinterpret_cast<const char*>(key_id), key_id_size),
- counter_block_str,
+ webm_iv,
std::string(reinterpret_cast<const char*>(data), kWebMHmacSize),
- data_offset,
+ sizeof(iv),
std::vector<SubsampleEntry>())));
return encrypted_buffer;
}
@@ -352,20 +324,6 @@ TEST_F(AesDecryptorTest, NormalWebMDecryption) {
frame.plain_text_size));
}
-TEST_F(AesDecryptorTest, UnencryptedFrameWebMDecryption) {
- const WebmEncryptedData& frame = kWebmEncryptedFrames[3];
- GenerateKeyRequest(frame.key_id, frame.key_id_size);
- AddKeyAndExpectToSucceed(frame.key_id, frame.key_id_size,
- frame.key, frame.key_size);
- scoped_refptr<DecoderBuffer> encrypted_data =
- CreateWebMEncryptedBuffer(frame.encrypted_data,
- frame.encrypted_data_size,
- frame.key_id, frame.key_id_size);
- ASSERT_NO_FATAL_FAILURE(DecryptAndExpectToSucceed(encrypted_data,
- frame.plain_text,
- frame.plain_text_size));
-}
-
TEST_F(AesDecryptorTest, WrongKey) {
const WebmEncryptedData& frame = kWebmEncryptedFrames[0];
GenerateKeyRequest(frame.key_id, frame.key_id_size);
diff --git a/media/webm/webm_cluster_parser.cc b/media/webm/webm_cluster_parser.cc
index 7878fa8..e9ef93e 100644
--- a/media/webm/webm_cluster_parser.cc
+++ b/media/webm/webm_cluster_parser.cc
@@ -14,11 +14,20 @@ namespace media {
// Generates a 16 byte CTR counter block. The CTR counter block format is a
// CTR IV appended with a CTR block counter. |iv| is an 8 byte CTR IV.
-// Returns a string of kDecryptionKeySize bytes.
-static std::string GenerateCounterBlock(uint64 iv) {
- std::string counter_block(reinterpret_cast<char*>(&iv), sizeof(iv));
- counter_block.append(DecryptConfig::kDecryptionKeySize - sizeof(iv), 0);
- return counter_block;
+// Always returns a valid pointer to a buffer of kDecryptionKeySize bytes.
+static scoped_array<uint8> GenerateCounterBlock(uint64 iv) {
+ scoped_array<uint8> counter_block_data(
+ new uint8[DecryptConfig::kDecryptionKeySize]);
+
+ // Set the IV.
+ memcpy(counter_block_data.get(), &iv, sizeof(iv));
+
+ // Set block counter to all 0's.
+ memset(counter_block_data.get() + sizeof(iv),
+ 0,
+ DecryptConfig::kDecryptionKeySize - sizeof(iv));
+
+ return counter_block_data.Pass();
}
WebMClusterParser::WebMClusterParser(int64 timecode_scale,
@@ -211,14 +220,12 @@ bool WebMClusterParser::OnBlock(int track_num, int timecode,
// Every encrypted Block has an HMAC and IV prepended to it. Current encrypted
// WebM request for comments specification is here
// http://wiki.webmproject.org/encryption/webm-encryption-rfc
- bool is_track_encrypted = track_num == video_.track_num() &&
- video_encryption_key_id_.get();
-
- // If stream is encrypted skip past the HMAC. Encrypted buffers must include
- // the signal byte, the IV (if frame is encrypted) and
- // the frame because the decryptor will verify this data before decryption.
- // The HMAC and IV will be copied into DecryptConfig.
- int offset = (is_track_encrypted) ? kWebMHmacSize : 0;
+ bool encrypted = track_num == video_.track_num() &&
+ video_encryption_key_id_.get();
+ // If encrypted skip past the HMAC. Encrypted buffers must include the IV and
+ // the encrypted frame because the decryptor will verify this data before
+ // decryption. The HMAC and IV will be copied into DecryptConfig.
+ int offset = (encrypted) ? kWebMHmacSize : 0;
// The first bit of the flags is set when the block contains only keyframes.
// http://www.matroska.org/technical/specs/index.html
@@ -226,31 +233,21 @@ bool WebMClusterParser::OnBlock(int track_num, int timecode,
scoped_refptr<StreamParserBuffer> buffer =
StreamParserBuffer::CopyFrom(data + offset, size - offset, is_keyframe);
- if (is_track_encrypted) {
- uint8 signal_byte = data[kWebMHmacSize];
- int data_offset = sizeof(signal_byte);
-
- // Setting the DecryptConfig object of the buffer while leaving the
- // initialization vector empty will tell the decryptor that the frame is
- // unencrypted but integrity should still be checked.
- std::string counter_block;
-
- if (signal_byte & kWebMFlagEncryptedFrame) {
- uint64 network_iv;
- memcpy(&network_iv, data + kWebMHmacSize + data_offset,
- sizeof(network_iv));
- const uint64 iv = base::NetToHost64(network_iv);
- counter_block = GenerateCounterBlock(iv);
- data_offset += sizeof(iv);
- }
+ if (encrypted) {
+ uint64 network_iv;
+ memcpy(&network_iv, data + kWebMHmacSize, sizeof(network_iv));
+ const uint64 iv = base::NetToHost64(network_iv);
+ scoped_array<uint8> counter_block(GenerateCounterBlock(iv));
buffer->SetDecryptConfig(scoped_ptr<DecryptConfig>(new DecryptConfig(
std::string(
reinterpret_cast<const char*>(video_encryption_key_id_.get()),
video_encryption_key_id_size_),
- counter_block,
+ std::string(
+ reinterpret_cast<const char*>(counter_block.get()),
+ DecryptConfig::kDecryptionKeySize),
std::string(reinterpret_cast<const char*>(data), kWebMHmacSize),
- data_offset,
+ sizeof(iv),
std::vector<SubsampleEntry>())));
}
diff --git a/media/webm/webm_constants.h b/media/webm/webm_constants.h
index 7d6f3ed..93041b2 100644
--- a/media/webm/webm_constants.h
+++ b/media/webm/webm_constants.h
@@ -202,7 +202,6 @@ const uint8 kWebMFlagKeyframe = 0x80;
// The size is from the WebM encrypted specification. Current encrypted WebM
// request for comments specification is here
// http://wiki.webmproject.org/encryption/webm-encryption-rfc
-const uint8 kWebMFlagEncryptedFrame = 0x1;
const int kWebMHmacSize = 12;
} // namespace media
generated by cgit v1.1 at 2025-02-04 07:04:38 +0000