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LibAudio: Prevent integer overflows in intermediate FLAC calculations

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Since we can have up to 32 bits of input data, multiplications may need
up to 63 bits. This was accounted for in some places, but by far not in
all, and oss-fuzz found multiple integer overflows. We now use i64 in
all of the decoding, since we need to rescale samples to float later on
anyways. If a final sample value ends up out of range (and the range can
be a maximum of 32 bits), we may get samples past 1, but that then is a
non-compliant input file, and using over-range samples (and most likely
clipping audio) is considerably less weird than overflowing and
glitching audio.
This commit is contained in:
kleines Filmröllchen 2023-06-26 15:12:20 +02:00 • committed by Jelle Raaijmakers
parent 9bece0d0da
commit 59c7ce3d54
2 changed files with 31 additions and 31 deletions
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12
Userland/Libraries/LibAudio/FlacLoader.h
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@ -69,14 +69,14 @@ private:
// Helper of next_frame that fetches a sub frame's header
ErrorOr<FlacSubframeHeader, LoaderError> next_subframe_header(BigEndianInputBitStream& bit_input, u8 channel_index);
// Helper of next_frame that decompresses a subframe
ErrorOr<Vector<i32>, LoaderError> parse_subframe(FlacSubframeHeader& subframe_header, BigEndianInputBitStream& bit_input);
ErrorOr<Vector<i64>, LoaderError> parse_subframe(FlacSubframeHeader& subframe_header, BigEndianInputBitStream& bit_input);
// Subframe-internal data decoders (heavy lifting)
ErrorOr<Vector<i32>, LoaderError> decode_fixed_lpc(FlacSubframeHeader& subframe, BigEndianInputBitStream& bit_input);
ErrorOr<Vector<i32>, LoaderError> decode_verbatim(FlacSubframeHeader& subframe, BigEndianInputBitStream& bit_input);
ErrorOr<Vector<i32>, LoaderError> decode_custom_lpc(FlacSubframeHeader& subframe, BigEndianInputBitStream& bit_input);
MaybeLoaderError decode_residual(Vector<i32>& decoded, FlacSubframeHeader& subframe, BigEndianInputBitStream& bit_input);
ErrorOr<Vector<i64>, LoaderError> decode_fixed_lpc(FlacSubframeHeader& subframe, BigEndianInputBitStream& bit_input);
ErrorOr<Vector<i64>, LoaderError> decode_verbatim(FlacSubframeHeader& subframe, BigEndianInputBitStream& bit_input);
ErrorOr<Vector<i64>, LoaderError> decode_custom_lpc(FlacSubframeHeader& subframe, BigEndianInputBitStream& bit_input);
MaybeLoaderError decode_residual(Vector<i64>& decoded, FlacSubframeHeader& subframe, BigEndianInputBitStream& bit_input);
// decode a single rice partition that has its own rice parameter
ALWAYS_INLINE ErrorOr<Vector<i32>, LoaderError> decode_rice_partition(u8 partition_type, u32 partitions, u32 partition_index, FlacSubframeHeader& subframe, BigEndianInputBitStream& bit_input);
ALWAYS_INLINE ErrorOr<Vector<i64>, LoaderError> decode_rice_partition(u8 partition_type, u32 partitions, u32 partition_index, FlacSubframeHeader& subframe, BigEndianInputBitStream& bit_input);
MaybeLoaderError load_seektable(FlacRawMetadataBlock&);
// Note that failing to read a Vorbis comment block is not treated as an error of the FLAC loader, since metadata is optional.
void load_vorbis_comment(FlacRawMetadataBlock&);