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perf: Speed up CRC when encrypting small files

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Chris Hennick 2024-06-14 15:47:41 -07:00
parent 185b1a1fd1
commit af7b27a21d
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GPG key ID: DA47AABA4961C509
1 changed files with 21 additions and 5 deletions
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26
src/write.rs
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@ -1038,8 +1038,7 @@ impl<W: Write + Seek> ZipWriter<W> {
let file_end = writer.stream_position()?;
debug_assert!(file_end >= self.stats.start);
file.compressed_size = file_end - self.stats.start;
file.crc32 = self.stats.hasher.clone().finalize();
let mut crc = true;
if let Some(aes_mode) = &mut file.aes_mode {
// We prefer using AE-1 which provides an extra CRC check, but for small files we
// switch to AE-2 to prevent being able to use the CRC value to to reconstruct the
@ -1047,13 +1046,17 @@ impl<W: Write + Seek> ZipWriter<W> {
//
// C.f. https://www.winzip.com/en/support/aes-encryption/#crc-faq
aes_mode.1 = if self.stats.bytes_written < 20 {
file.crc32 = 0;
crc = false;
AesVendorVersion::Ae2
} else {
AesVendorVersion::Ae1
}
};
}
file.crc32 = if (crc) {
self.stats.hasher.clone().finalize()
} else {
0
};
update_aes_extra_data(writer, file)?;
update_local_file_header(writer, file)?;
writer.seek(SeekFrom::Start(file_end))?;
@ -2722,4 +2725,17 @@ mod test {
let _ = writer.finish_into_readable()?;
Ok(())
}
#[test]
fn test_fuzz_crash_2024_06_14a() -> ZipResult<()> {
let mut writer = ZipWriter::new(Cursor::new(Vec::new()));
writer.set_flush_on_finish_file(false);
let options = FileOptions { compression_method: Stored, compression_level: None, last_modified_time: DateTime::from_date_and_time(2083, 5, 30, 21, 45, 35)?, permissions: None, large_file: false, encrypt_with: None, extended_options: ExtendedFileOptions {extra_data: vec![].into(), central_extra_data: vec![].into()}, alignment: 2565, ..Default::default() };
writer.add_symlink_from_path("", "", options)?;
writer.abort_file()?;
let options = FileOptions { compression_method: Stored, compression_level: None, last_modified_time: DateTime::default(), permissions: None, large_file: false, encrypt_with: None, extended_options: ExtendedFileOptions {extra_data: vec![].into(), central_extra_data: vec![].into()}, alignment: 0, ..Default::default() };
writer.start_file_from_path("", options)?;
let _ = writer.finish_into_readable()?;
Ok(())
}
}