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std.compress.zstandard: fix crashes

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This commit is contained in:
dweiller 2023-02-02 18:01:03 +11:00
parent a180fcc93d
commit 6e3e72884b
1 changed files with 12 additions and 6 deletions
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18
lib/std/compress/zstandard/decompress.zig
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@ -695,11 +695,11 @@ pub fn decodeZStandardFrameAlloc(
var match_fse_data: [types.compressed_block.table_size_max.match]Table.Fse = undefined;
var offset_fse_data: [types.compressed_block.table_size_max.offset]Table.Fse = undefined;
var block_header = decodeBlockHeader(src[consumed_count..][0..3]);
var block_header = try decodeBlockHeaderSlice(src[consumed_count..]);
consumed_count += 3;
var decode_state = DecodeState.init(&literal_fse_data, &match_fse_data, &offset_fse_data);
while (true) : ({
block_header = decodeBlockHeader(src[consumed_count..][0..3]);
block_header = try decodeBlockHeaderSlice(src[consumed_count..]);
consumed_count += 3;
}) {
if (block_header.block_size > frame_context.block_size_max) return error.BlockSizeOverMaximum;
@ -737,6 +737,7 @@ const DecodeBlockError = error{
ReservedBlock,
MalformedRleBlock,
MalformedCompressedBlock,
EndOfStream,
};
/// Convenience wrapper for decoding all blocks in a frame; see `decodeBlock()`.
@ -751,13 +752,13 @@ pub fn decodeFrameBlocks(
var match_fse_data: [types.compressed_block.table_size_max.match]Table.Fse = undefined;
var offset_fse_data: [types.compressed_block.table_size_max.offset]Table.Fse = undefined;
var block_header = decodeBlockHeader(src[0..3]);
var block_header = try decodeBlockHeaderSlice(src);
var bytes_read: usize = 3;
defer consumed_count.* += bytes_read;
var decode_state = DecodeState.init(&literal_fse_data, &match_fse_data, &offset_fse_data);
var written_count: usize = 0;
while (true) : ({
block_header = decodeBlockHeader(src[bytes_read..][0..3]);
block_header = try decodeBlockHeaderSlice(src[bytes_read..]);
bytes_read += 3;
}) {
const written_size = try decodeBlock(
@ -847,6 +848,7 @@ pub fn decodeBlock(
bytes_read += bit_stream_bytes.len;
}
if (bytes_read != block_size) return error.MalformedCompressedBlock;
if (decode_state.literal_written_count < literals.header.regenerated_size) {
const len = literals.header.regenerated_size - decode_state.literal_written_count;
@ -855,7 +857,6 @@ pub fn decodeBlock(
bytes_written += len;
}
assert(bytes_read == block_header.block_size);
consumed_count.* += bytes_read;
return bytes_written;
},
@ -931,6 +932,7 @@ pub fn decodeBlockRingBuffer(
bytes_read += bit_stream_bytes.len;
}
if (bytes_read != block_size) return error.MalformedCompressedBlock;
if (decode_state.literal_written_count < literals.header.regenerated_size) {
const len = literals.header.regenerated_size - decode_state.literal_written_count;
@ -939,7 +941,6 @@ pub fn decodeBlockRingBuffer(
bytes_written += len;
}
assert(bytes_read == block_header.block_size);
consumed_count.* += bytes_read;
if (bytes_written > block_size_max) return error.BlockSizeOverMaximum;
return bytes_written;
@ -1101,6 +1102,11 @@ pub fn decodeBlockHeader(src: *const [3]u8) frame.ZStandard.Block.Header {
};
}
pub fn decodeBlockHeaderSlice(src: []const u8) error{EndOfStream}!frame.ZStandard.Block.Header {
if (src.len < 3) return error.EndOfStream;
return decodeBlockHeader(src[0..3]);
}
/// Decode a `LiteralsSection` from `src`, incrementing `consumed_count` by the
/// number of bytes the section uses.
///