diff options
Diffstat (limited to 'toolkit/components/mediasniffer/nsMediaSniffer.cpp')
| -rw-r--r-- | toolkit/components/mediasniffer/nsMediaSniffer.cpp | 261 |
1 files changed, 261 insertions, 0 deletions
diff --git a/toolkit/components/mediasniffer/nsMediaSniffer.cpp b/toolkit/components/mediasniffer/nsMediaSniffer.cpp new file mode 100644 index 0000000000..e1851d3276 --- /dev/null +++ b/toolkit/components/mediasniffer/nsMediaSniffer.cpp @@ -0,0 +1,261 @@ +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* vim:set ts=2 sw=2 sts=2 tw=80 et cindent: */ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +#include "ADTSDemuxer.h" +#include "mozilla/ArrayUtils.h" +#include "mozilla/ModuleUtils.h" +#include "mozilla/ScopeExit.h" +#include "mozilla/StaticPrefs_media.h" +#include "mozilla/Telemetry.h" +#include "mp3sniff.h" +#include "nestegg/nestegg.h" +#include "nsHttpChannel.h" +#include "nsIClassInfoImpl.h" +#include "nsIChannel.h" +#include "nsMediaSniffer.h" +#include "nsMimeTypes.h" +#include "nsQueryObject.h" +#include "nsString.h" + +#include <algorithm> + +// The minimum number of bytes that are needed to attempt to sniff an mp4 file. +static const unsigned MP4_MIN_BYTES_COUNT = 12; +// The maximum number of bytes to consider when attempting to sniff a file. +static const uint32_t MAX_BYTES_SNIFFED = 512; +// The maximum number of bytes to consider when attempting to sniff for a mp3 +// bitstream. +// This is 320kbps * 144 / 32kHz + 1 padding byte + 4 bytes of capture pattern. +static const uint32_t MAX_BYTES_SNIFFED_MP3 = 320 * 144 / 32 + 1 + 4; +// Multi-channel low sample-rate AAC packets can be huge, have a higher maximum +// size. +static const uint32_t MAX_BYTES_SNIFFED_ADTS = 8096; + +NS_IMPL_ISUPPORTS(nsMediaSniffer, nsIContentSniffer) + +nsMediaSnifferEntry nsMediaSniffer::sSnifferEntries[] = { + // The string OggS, followed by the null byte. + PATTERN_ENTRY("\xFF\xFF\xFF\xFF\xFF", "OggS", APPLICATION_OGG), + // The string RIFF, followed by four bytes, followed by the string WAVE, + // followed by 8 bytes, followed by 0x0055, the codec identifier for mp3 in + // a RIFF container. This entry MUST be before the next one, which is + // assumed to be a WAV file containing PCM data. + PATTERN_ENTRY("\xFF\xFF\xFF\xFF" + "\x00\x00\x00\x00" + "\xFF\xFF\xFF\xFF" + "\x00\x00\x00\x00" + "\x00\x00\x00\x00" + "\xFF\xFF", + "RIFF" + "\x00\x00\x00\x00" + "WAVE" + "\x00\x00\x00\x00" + "\x00\x00\x00\x00" + "\x55\x00", + AUDIO_MP3), + // The string RIFF, followed by four bytes, followed by the string WAVE + PATTERN_ENTRY("\xFF\xFF\xFF\xFF\x00\x00\x00\x00\xFF\xFF\xFF\xFF", + "RIFF\x00\x00\x00\x00WAVE", AUDIO_WAV), + // mp3 with ID3 tags, the string "ID3". + PATTERN_ENTRY("\xFF\xFF\xFF", "ID3", AUDIO_MP3), + // FLAC with standard header + PATTERN_ENTRY("\xFF\xFF\xFF\xFF", "fLaC", AUDIO_FLAC), + PATTERN_ENTRY("\xFF\xFF\xFF\xFF\xFF\xFF\xFF", "#EXTM3U", + APPLICATION_MPEGURL)}; + +using PatternLabel = mozilla::Telemetry::LABELS_MEDIA_SNIFFER_MP4_BRAND_PATTERN; + +struct nsMediaSnifferFtypEntry : nsMediaSnifferEntry { + nsMediaSnifferFtypEntry(nsMediaSnifferEntry aBase, const PatternLabel aLabel) + : nsMediaSnifferEntry(aBase), mLabel(aLabel) {} + PatternLabel mLabel; +}; + +// For a complete list of file types, see http://www.ftyps.com/index.html +nsMediaSnifferFtypEntry sFtypEntries[] = { + {PATTERN_ENTRY("\xFF\xFF\xFF", "mp4", VIDEO_MP4), + PatternLabel::ftyp_mp4}, // Could be mp41 or mp42. + {PATTERN_ENTRY("\xFF\xFF\xFF", "avc", VIDEO_MP4), + PatternLabel::ftyp_avc}, // Could be avc1, avc2, ... + {PATTERN_ENTRY("\xFF\xFF\xFF\xFF", "3gp4", VIDEO_MP4), + PatternLabel::ftyp_3gp4}, // 3gp4 is based on MP4 + {PATTERN_ENTRY("\xFF\xFF\xFF", "3gp", VIDEO_3GPP), + PatternLabel::ftyp_3gp}, // Could be 3gp5, ... + {PATTERN_ENTRY("\xFF\xFF\xFF", "M4V", VIDEO_MP4), PatternLabel::ftyp_M4V}, + {PATTERN_ENTRY("\xFF\xFF\xFF", "M4A", AUDIO_MP4), PatternLabel::ftyp_M4A}, + {PATTERN_ENTRY("\xFF\xFF\xFF", "M4P", AUDIO_MP4), PatternLabel::ftyp_M4P}, + {PATTERN_ENTRY("\xFF\xFF", "qt", VIDEO_QUICKTIME), PatternLabel::ftyp_qt}, + {PATTERN_ENTRY("\xFF\xFF\xFF", "crx", APPLICATION_OCTET_STREAM), + PatternLabel::ftyp_crx}, + {PATTERN_ENTRY("\xFF\xFF\xFF", "iso", VIDEO_MP4), + PatternLabel::ftyp_iso}, // Could be isom or iso2. + {PATTERN_ENTRY("\xFF\xFF\xFF\xFF", "mmp4", VIDEO_MP4), + PatternLabel::ftyp_mmp4}, + {PATTERN_ENTRY("\xFF\xFF\xFF\xFF", "avif", IMAGE_AVIF), + PatternLabel::ftyp_avif}, +}; + +static bool MatchesBrands(const uint8_t aData[4], nsACString& aSniffedType) { + for (const auto& currentEntry : sFtypEntries) { + bool matched = true; + MOZ_ASSERT(currentEntry.mLength <= 4, + "Pattern is too large to match brand strings."); + for (uint32_t j = 0; j < currentEntry.mLength; ++j) { + if ((currentEntry.mMask[j] & aData[j]) != currentEntry.mPattern[j]) { + matched = false; + break; + } + } + if (matched) { + // If we eventually remove the "iso" pattern entry per bug 1725190, + // this block should be removed and the bug1725190.cr3 test in + // test_mediasniffer_ext.js will need to be updated + if (!mozilla::StaticPrefs::media_mp4_sniff_iso_brand() && + currentEntry.mLabel == PatternLabel::ftyp_iso) { + continue; + } + + aSniffedType.AssignASCII(currentEntry.mContentType); + AccumulateCategorical(currentEntry.mLabel); + return true; + } + } + + return false; +} + +// This function implements sniffing algorithm for MP4 family file types, +// including MP4 (described at +// http://mimesniff.spec.whatwg.org/#signature-for-mp4), M4A (Apple iTunes +// audio), and 3GPP. +bool MatchesMP4(const uint8_t* aData, const uint32_t aLength, + nsACString& aSniffedType) { + if (aLength <= MP4_MIN_BYTES_COUNT) { + return false; + } + // Conversion from big endian to host byte order. + uint32_t boxSize = + (uint32_t)(aData[3] | aData[2] << 8 | aData[1] << 16 | aData[0] << 24); + + // Boxsize should be evenly divisible by 4. + if (boxSize % 4 || aLength < boxSize) { + return false; + } + // The string "ftyp". + if (aData[4] != 0x66 || aData[5] != 0x74 || aData[6] != 0x79 || + aData[7] != 0x70) { + return false; + } + if (MatchesBrands(&aData[8], aSniffedType)) { + return true; + } + // Skip minor_version (bytes 12-15). + uint32_t bytesRead = 16; + while (bytesRead < boxSize) { + if (MatchesBrands(&aData[bytesRead], aSniffedType)) { + return true; + } + bytesRead += 4; + } + + return false; +} + +static bool MatchesWebM(const uint8_t* aData, const uint32_t aLength) { + return nestegg_sniff((uint8_t*)aData, aLength); +} + +// This function implements mp3 sniffing based on parsing +// packet headers and looking for expected boundaries. +static bool MatchesMP3(const uint8_t* aData, const uint32_t aLength) { + return mp3_sniff(aData, (long)aLength); +} + +static bool MatchesADTS(const uint8_t* aData, const uint32_t aLength) { + return mozilla::ADTSDemuxer::ADTSSniffer(aData, aLength); +} + +NS_IMETHODIMP +nsMediaSniffer::GetMIMETypeFromContent(nsIRequest* aRequest, + const uint8_t* aData, + const uint32_t aLength, + nsACString& aSniffedType) { + const uint32_t clampedLength = std::min(aLength, MAX_BYTES_SNIFFED); + + nsCOMPtr<nsIChannel> channel = do_QueryInterface(aRequest); + + auto maybeUpdate = mozilla::MakeScopeExit([channel]() { + if (channel && XRE_IsParentProcess()) { + if (RefPtr<mozilla::net::nsHttpChannel> httpChannel = + do_QueryObject(channel)) { + // If the audio or video type pattern matching algorithm given bytes + // does not return undefined, then disable the further check and allow + // the response. + httpChannel->DisableIsOpaqueResponseAllowedAfterSniffCheck( + mozilla::net::nsHttpChannel::SnifferType::Media); + } + }; + }); + + // Check if this is a toplevel document served as application/octet-stream + // to disable sniffing and allow the file to download. See: Bug 1828441 + if (channel && XRE_IsParentProcess()) { + nsCOMPtr<nsILoadInfo> loadInfo = channel->LoadInfo(); + nsAutoCString mimeType; + channel->GetContentType(mimeType); + if (mimeType.EqualsLiteral(APPLICATION_OCTET_STREAM) && + loadInfo->GetExternalContentPolicyType() == + ExtContentPolicy::TYPE_DOCUMENT) { + aSniffedType.AssignLiteral(APPLICATION_OCTET_STREAM); + maybeUpdate.release(); + return NS_ERROR_NOT_AVAILABLE; + } + } + + for (const auto& currentEntry : sSnifferEntries) { + if (clampedLength < currentEntry.mLength || currentEntry.mLength == 0) { + continue; + } + bool matched = true; + for (uint32_t j = 0; j < currentEntry.mLength; ++j) { + if ((currentEntry.mMask[j] & aData[j]) != currentEntry.mPattern[j]) { + matched = false; + break; + } + } + if (matched) { + aSniffedType.AssignASCII(currentEntry.mContentType); + return NS_OK; + } + } + + if (MatchesMP4(aData, clampedLength, aSniffedType)) { + return NS_OK; + } + + if (MatchesWebM(aData, clampedLength)) { + aSniffedType.AssignLiteral(VIDEO_WEBM); + return NS_OK; + } + + // Bug 950023: 512 bytes are often not enough to sniff for mp3. + if (MatchesMP3(aData, std::min(aLength, MAX_BYTES_SNIFFED_MP3))) { + aSniffedType.AssignLiteral(AUDIO_MP3); + return NS_OK; + } + + if (MatchesADTS(aData, std::min(aLength, MAX_BYTES_SNIFFED_ADTS))) { + aSniffedType.AssignLiteral(AUDIO_AAC); + return NS_OK; + } + + maybeUpdate.release(); + + // Could not sniff the media type, we are required to set it to + // application/octet-stream. + aSniffedType.AssignLiteral(APPLICATION_OCTET_STREAM); + return NS_ERROR_NOT_AVAILABLE; +} |