mirror of
https://github.com/RGBCube/serenity
synced 2025-10-31 16:32:45 +00:00
f532421c9c
This commit adds a verify-less try_create method to the Zlib decompressor to allow for graceful failures of parsing the Zlib headers.
92 lines
2.9 KiB
C++
92 lines
2.9 KiB
C++
/*
|
|
* Copyright (c) 2020, the SerenityOS developers
|
|
* All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions are met:
|
|
*
|
|
* 1. Redistributions of source code must retain the above copyright notice, this
|
|
* list of conditions and the following disclaimer.
|
|
*
|
|
* 2. Redistributions in binary form must reproduce the above copyright notice,
|
|
* this list of conditions and the following disclaimer in the documentation
|
|
* and/or other materials provided with the distribution.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
|
|
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
|
|
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
|
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
|
|
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
|
|
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
|
|
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
|
|
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
|
*/
|
|
|
|
#include <AK/Span.h>
|
|
#include <AK/Types.h>
|
|
#include <AK/Vector.h>
|
|
#include <LibCompress/Deflate.h>
|
|
#include <LibCompress/Zlib.h>
|
|
|
|
namespace Compress {
|
|
|
|
Optional<Zlib> Zlib::try_create(ReadonlyBytes data)
|
|
{
|
|
if (data.size() < 6)
|
|
return {}; // header + footer size is 6
|
|
|
|
Zlib zlib { data };
|
|
|
|
u8 compression_info = data.at(0);
|
|
u8 flags = data.at(1);
|
|
|
|
zlib.m_compression_method = compression_info & 0xF;
|
|
zlib.m_compression_info = (compression_info >> 4) & 0xF;
|
|
zlib.m_check_bits = flags & 0xF;
|
|
zlib.m_has_dictionary = (flags >> 5) & 0x1;
|
|
zlib.m_compression_level = (flags >> 6) & 0x3;
|
|
|
|
if (zlib.m_compression_method != 8 || zlib.m_compression_info > 7)
|
|
return {}; // non-deflate compression
|
|
|
|
if (zlib.m_has_dictionary)
|
|
return {}; // we dont support pre-defined dictionaries
|
|
|
|
if ((compression_info * 256 + flags) % 31 != 0)
|
|
return {}; // error correction code doesnt match
|
|
|
|
zlib.m_data_bytes = data.slice(2, data.size() - 2 - 4);
|
|
return zlib;
|
|
}
|
|
|
|
Zlib::Zlib(const ReadonlyBytes& data)
|
|
: m_input_data(data)
|
|
{
|
|
}
|
|
|
|
Optional<ByteBuffer> Zlib::decompress()
|
|
{
|
|
return DeflateDecompressor::decompress_all(m_data_bytes);
|
|
}
|
|
|
|
Optional<ByteBuffer> Zlib::decompress_all(ReadonlyBytes bytes)
|
|
{
|
|
auto zlib = try_create(bytes);
|
|
if (!zlib.has_value())
|
|
return {};
|
|
return zlib->decompress();
|
|
}
|
|
|
|
u32 Zlib::checksum()
|
|
{
|
|
if (!m_checksum) {
|
|
auto bytes = m_input_data.slice(m_input_data.size() - 4, 4);
|
|
m_checksum = bytes.at(0) << 24 | bytes.at(1) << 16 | bytes.at(2) << 8 || bytes.at(3);
|
|
}
|
|
|
|
return m_checksum;
|
|
}
|
|
|
|
}
|