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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-19 00:47:55 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-19 00:47:55 +0000 |
commit | 26a029d407be480d791972afb5975cf62c9360a6 (patch) | |
tree | f435a8308119effd964b339f76abb83a57c29483 /media/psshparser/PsshParser.cpp | |
parent | Initial commit. (diff) | |
download | firefox-26a029d407be480d791972afb5975cf62c9360a6.tar.xz firefox-26a029d407be480d791972afb5975cf62c9360a6.zip |
Adding upstream version 124.0.1.upstream/124.0.1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | media/psshparser/PsshParser.cpp | 185 |
1 files changed, 185 insertions, 0 deletions
diff --git a/media/psshparser/PsshParser.cpp b/media/psshparser/PsshParser.cpp new file mode 100644 index 0000000000..9a47979164 --- /dev/null +++ b/media/psshparser/PsshParser.cpp @@ -0,0 +1,185 @@ +/* + * Copyright 2015, Mozilla Foundation and contributors + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#include "PsshParser.h" + +#include <assert.h> +#include <memory.h> + +#include <algorithm> +#include <limits> +#include <utility> + +#include "mozilla/Assertions.h" +#include "mozilla/EndianUtils.h" + +// Stripped down version of mp4_demuxer::ByteReader, stripped down to make it +// easier to link into ClearKey DLL and gtest. +class ByteReader { + public: + ByteReader(const uint8_t* aData, size_t aSize) + : mPtr(aData), mRemaining(aSize), mLength(aSize) {} + + size_t Offset() const { return mLength - mRemaining; } + + size_t Remaining() const { return mRemaining; } + + size_t Length() const { return mLength; } + + bool CanRead8() const { return mRemaining >= 1; } + + uint8_t ReadU8() { + auto ptr = Read(1); + if (!ptr) { + MOZ_ASSERT(false); + return 0; + } + return *ptr; + } + + bool CanRead32() const { return mRemaining >= 4; } + + uint32_t ReadU32() { + auto ptr = Read(4); + if (!ptr) { + MOZ_ASSERT(false); + return 0; + } + return mozilla::BigEndian::readUint32(ptr); + } + + const uint8_t* Read(size_t aCount) { + if (aCount > mRemaining) { + mRemaining = 0; + return nullptr; + } + mRemaining -= aCount; + + const uint8_t* result = mPtr; + mPtr += aCount; + + return result; + } + + const uint8_t* Seek(size_t aOffset) { + if (aOffset > mLength) { + MOZ_ASSERT(false); + return nullptr; + } + + mPtr = mPtr - Offset() + aOffset; + mRemaining = mLength - aOffset; + return mPtr; + } + + private: + const uint8_t* mPtr; + size_t mRemaining; + const size_t mLength; +}; + +#define FOURCC(a, b, c, d) ((a << 24) + (b << 16) + (c << 8) + d) + +// System ID identifying the cenc v2 pssh box format; specified at: +// https://dvcs.w3.org/hg/html-media/raw-file/tip/encrypted-media/cenc-format.html +const uint8_t kSystemID[] = {0x10, 0x77, 0xef, 0xec, 0xc0, 0xb2, 0x4d, 0x02, + 0xac, 0xe3, 0x3c, 0x1e, 0x52, 0xe2, 0xfb, 0x4b}; + +bool ParseCENCInitData(const uint8_t* aInitData, uint32_t aInitDataSize, + std::vector<std::vector<uint8_t>>& aOutKeyIds) { + aOutKeyIds.clear(); + std::vector<std::vector<uint8_t>> keyIds; + ByteReader reader(aInitData, aInitDataSize); + while (reader.CanRead32()) { + // Box size. For the common system Id, ignore this, as some useragents + // handle invalid box sizes. + const size_t start = reader.Offset(); + const size_t size = reader.ReadU32(); + if (size > std::numeric_limits<size_t>::max() - start) { + // Ensure 'start + size' calculation below can't overflow. + return false; + } + const size_t end = start + size; + if (end > reader.Length()) { + // Ridiculous sized box. + return false; + } + + // PSSH box type. + if (!reader.CanRead32()) { + return false; + } + uint32_t box = reader.ReadU32(); + if (box != FOURCC('p', 's', 's', 'h')) { + return false; + } + + // 1 byte version, 3 bytes flags. + if (!reader.CanRead32()) { + return false; + } + uint8_t version = reader.ReadU8(); + if (version != 1) { + // Ignore pssh boxes with wrong version. + reader.Seek(std::max<size_t>(reader.Offset(), end)); + continue; + } + reader.Read(3); // skip flags. + + // SystemID + const uint8_t* sid = reader.Read(sizeof(kSystemID)); + if (!sid) { + // Insufficient bytes to read SystemID. + return false; + } + + if (memcmp(kSystemID, sid, sizeof(kSystemID))) { + // Ignore pssh boxes with wrong system ID. + reader.Seek(std::max<size_t>(reader.Offset(), end)); + continue; + } + + if (!reader.CanRead32()) { + return false; + } + uint32_t kidCount = reader.ReadU32(); + + if (kidCount * CENC_KEY_LEN > reader.Remaining()) { + // Not enough bytes remaining to read all keys. + return false; + } + + for (uint32_t i = 0; i < kidCount; i++) { + const uint8_t* kid = reader.Read(CENC_KEY_LEN); + keyIds.push_back(std::vector<uint8_t>(kid, kid + CENC_KEY_LEN)); + } + + // Size of extra data. EME CENC format spec says datasize should + // always be 0. We explicitly read the datasize, in case the box + // size was 0, so that we get to the end of the box. + if (!reader.CanRead32()) { + return false; + } + reader.ReadU32(); + + // Jump forwards to the end of the box, skipping any padding. + if (size) { + reader.Seek(end); + } + } + aOutKeyIds = std::move(keyIds); + return true; +} |