mirror of https://git.tukaani.org/xz.git
273 lines
11 KiB
Plaintext
273 lines
11 KiB
Plaintext
|
|
.lzma Test Files
|
|
----------------
|
|
|
|
0. Introduction
|
|
|
|
This directory contains bunch of files to test handling of .lzma files
|
|
in .lzma decoder implementations. Many of the files have been created
|
|
by hand with a hex editor, thus there is no better "source code" than
|
|
the files themselves. All the test files (*.lzma) and this README have
|
|
been put into the public domain.
|
|
|
|
|
|
1. File Types
|
|
|
|
Good files (good-*.lzma) must decode successfully without requiring
|
|
a lot of CPU time or RAM. If the decoder supports only Single-Block
|
|
Streams, then good-multi-*.lzma won't decode, of course.
|
|
|
|
Bad files (bad-*.lzma) must cause the decoder to give an error. Like
|
|
with the good files, these files must not require a lot of CPU time
|
|
or RAM before they get detected to be broken.
|
|
|
|
Malicious files (malicious-*.lzma) are good in terms of the file format
|
|
specification, but try to trigger excessive CPU, RAM or disk usage in
|
|
the decoder. To prevent malicious files from putting the decoder in
|
|
inifinite loop (*), eating all available RAM or disk space, decoders
|
|
should have internal limiters that catch these situations.
|
|
|
|
(*) Strictly speaking not infinite, but if decoding of a small file
|
|
would take a few weeks or even years, it's an infinite loop in
|
|
practice.
|
|
|
|
|
|
2. Descriptions of Individual Files
|
|
|
|
2.1. Good Files
|
|
|
|
good-single-none.lzma uses implicit Copy filter with known Uncompressed
|
|
Size.
|
|
|
|
good-single-none-pad.lzma is good-single-none.lzma with Footer Padding.
|
|
|
|
good-cat-single-none-pad.lzma is two good-single-none-pad.lzma files
|
|
concatenated as is. Fully decoding this file requires that the decoder
|
|
supports decoding concatenated files.
|
|
|
|
good-single-subblock_implicit.lzma uses implicit Subblock filter.
|
|
|
|
good-single-lzma.lzma is LZMA compressed file with EOPM.
|
|
|
|
good-single-subblock-lzma.lzma has basic combination of Subblock and
|
|
LZMA filters.
|
|
|
|
good-single-none-empty_1.lzma is an empty file with implicit Copy
|
|
filter and no integrity Check.
|
|
|
|
good-single-none-empty_2.lzma is an empty file with implicit Copy
|
|
filter and CRC32 as Check.
|
|
|
|
good-single-none-empty_3.lzma is an empty file with implicit Copy
|
|
filter, known Compressed Size, and no integrity Check.
|
|
|
|
good-single-lzma-empty.lzma is an empty file with LZMA filter and no
|
|
integrity Check.
|
|
|
|
good-single-subblock_rle.lzma takes advantage of Subblock filter's
|
|
run-length encoding.
|
|
|
|
good-single-delta-lzma.tiff.lzma is an image file that compresses
|
|
better with Delta+LZMA than with plain LZMA.
|
|
|
|
good-single-x86-lzma.lzma uses the x86 filter (BCJ) and LZMA. The
|
|
uncompressed file is compress_prepared_bcj_x86 found from the tests
|
|
directory.
|
|
|
|
good-single-sparc-lzma.lzma uses the SPARC filter and LZMA. The
|
|
uncompressed file is compress_prepared_bcj_sparc found from the tests
|
|
directory.
|
|
|
|
good-single-lzma-flush_1.lzma has a flush marker in the middle of
|
|
the file, and no EOPM.
|
|
|
|
good-single-lzma-flush_2.lzma has a flush marker in the middle of
|
|
the file and just before EOPM.
|
|
|
|
good-multi-none-1.lzma is a basic Multi-Block Stream with two Data
|
|
Blocks and Footer Metadata Block.
|
|
|
|
good-multi-none-2.lzma is good-multi-none-1.lzma with Total Size and
|
|
Uncompressed Size added to the Footer Metadata Block.
|
|
|
|
good-multi-none-extra_1.lzma has the `Extra is present' flag set but
|
|
no actual Extra Records.
|
|
|
|
good-multi-none-extra_2.lzma has two non-empty Extra Records.
|
|
|
|
good-multi-none-extra_3.lzma has an Extra Record that has empty Data.
|
|
|
|
good-multi-none-header_1.lzma has very minimal Header Metadata Block
|
|
with only the Metadata Flags field.
|
|
|
|
good-multi-none-header_2.lzma has all information in both Header and
|
|
Footer Metadata Blocks. The Size of Header Metadata Block has wrong
|
|
value in Header Metadata Block, but this value must be ignored by
|
|
the decoder in case of Header Metadata Block.
|
|
|
|
good-multi-none-header_3.lzma has Index only in the Header Metadata
|
|
Block. Footer Metadata Block contains only Size of Header Metadata
|
|
Block and Total Size.
|
|
|
|
good-multi-none-block_1.lzma has Index in Header Metadata Block. The
|
|
Compressed Size and Uncompressed Size fields are present in the Data
|
|
Blocks. There is some Footer Padding between the Blocks.
|
|
|
|
good-multi-none-block_2.lzma has Index in Header Metadata Block. The
|
|
Uncompressed Size field is present in Data Blocks and no EOPM is used.
|
|
|
|
|
|
2.2. Bad Files
|
|
|
|
bad-single-none-truncated.lzma is good-single-none.lzma without the
|
|
last byte of the file.
|
|
|
|
bad-cat-single-none-pad_garbage_1.lzma is good-cat-single-none-pad.lzma
|
|
with 0xFE appended to the end of the file. 0xFE doesn't begin .lzma
|
|
or LZMA_Alone format file.
|
|
|
|
bad-cat-single-none-pad_garbage_2.lzma is good-cat-single-none-pad.lzma
|
|
with 0xFF appended to the end of the file. 0xFF begins .lzma format
|
|
file, thus the decoder has to detect that the file is incomplete.
|
|
|
|
bad-cat-single-none-pad_garbage_3.lzma is good-cat-single-none-pad.lzma
|
|
with 0x5D appended to the end of the file. 0x5D is the most common
|
|
first byte of LZMA_Alone format file.
|
|
|
|
bad-single-none-footer_filter_flags.lzma has different Stream Flags
|
|
in Stream Footer than in Stream Header.
|
|
|
|
bad-single-none-too_long_vli.lzma has 10-byte variable-length integer.
|
|
|
|
bad-single-none-empty.lzma is like good-single-none-empty_3.lzma but
|
|
with non-zero value in the Compressed Size field.
|
|
|
|
bad-single-data_after_eopm_1.lzma has LZMA+Subblock, where the Subblock
|
|
filter gives one byte of data to LZMA after LZMA has detected EOPM.
|
|
|
|
bad-single-data_after_eopm_2.lzma is like
|
|
bad-single-data_after_eopm_1.lzma but Subblock gives 256 MiB of data
|
|
to LZMA after LZMA has detected EOPM.
|
|
|
|
bad-single-subblock_subblock.lzma has Subblock+Subblock, where the
|
|
Subblock decoder is given End of Input in the middle of a Subblock.
|
|
|
|
bad-single-subblock-padding_loop.lzma contains huge amount of
|
|
consecutive Padding bytes, which isn't allowed by the Subblock filter
|
|
format. If it were allowed, this file would hang the decoder for very
|
|
long time (weeks to years).
|
|
|
|
bad-single-subblock1023-slow.lzma is similar to
|
|
malicious-single-subblock31-slow.lzma except that this uses 1023 bytes
|
|
of Padding in every place instead of 31 bytes. The Subblock filter
|
|
format specification allows only 31-byte Padings, thus this file must
|
|
get detected as bad without producing any output. Allowing larger
|
|
Padding than 31 bytes was considered (so this test file was created),
|
|
but it seemed to be a bad idea since it would increase worst-case CPU
|
|
usage.
|
|
|
|
bad-single-lzma-flush_beginning.lzma has flush marker in the beginning
|
|
of the LZMA data.
|
|
|
|
bad-single-lzma-flush_twice.lzma has two flush markers with no data
|
|
between them.
|
|
|
|
bad-multi-none-1.lzma has data after the last field in the Metadata
|
|
Block and the `Extra is present' flag is not set.
|
|
|
|
bad-multi-none-2.lzma has wrong Total Size in Footer Metadata Block.
|
|
|
|
bad-multi-none-3.lzma has wrong Uncompressed Size in Footer Metadata
|
|
Block.
|
|
|
|
bad-multi-none-index_1.lzma has wrong value in the Number of Data
|
|
Blocks field.
|
|
|
|
bad-multi-none-index_2.lzma has too short Metadata to contain all
|
|
the Index Records.
|
|
|
|
bad-multi-none-index_3.lzma has wrong value in Total Size field in
|
|
the Index.
|
|
|
|
bad-multi-none-index_4.lzma has wrong value in Uncompressed Size field
|
|
in the Index.
|
|
|
|
bad-multi-none-extra_1.lzma has incomplete Extra Record at the end of
|
|
the Metadata Block.
|
|
|
|
bad-multi-none-extra_2.lzma has incomplete variable-length integer as
|
|
Extra Record ID.
|
|
|
|
bad-multi-none-extra_3.lzma has incomplete Extra Record at the end of
|
|
the Metadata Block.
|
|
|
|
bad-multi-none-header_1.lzma has empty Header Metadata Block (even
|
|
the Metadata Flags field is not present).
|
|
|
|
bad-multi-none-header_2.lzma has Index in the Header Metadata Block,
|
|
which describes only one Data Block, while the Stream actually has
|
|
two Data Blocks. A sophisticated decoder should give an error when
|
|
it detects the second Data Block; all Multi-Block decoders must
|
|
detect the file as corrupt at some point.
|
|
|
|
bad-multi-none-header_3.lzma contains too small Total Size in Header
|
|
Metadata Block. A sophisticated decoder should abort decoding before
|
|
the second Data Block, preferably before the first Data Block has
|
|
been finished; all Multi-Block decoders must detect the file as
|
|
corrupt at some point.
|
|
|
|
bad-multi-none-header_4.lzma is like bad-multi-none-header_3.lzma but
|
|
with too small Uncompressed Size.
|
|
|
|
bad-multi-none-header_5.lzma has Index in the Header Metadata Block,
|
|
but the Total Size field is missing from the Footer Metadata Block.
|
|
|
|
bad-multi-none-header_6.lzma has both Index and Total Size in Header
|
|
Metadata Block, but Total Size doesn't match the Index. A sophisticated
|
|
decoder should abort before decoding any Data Blocks; all Multi-Block
|
|
decoders must detect the file as corrupt at some point.
|
|
|
|
bad-multi-none-header_7.lzma has zero as the Size of Header Metadata
|
|
Block in the Header Metadata Block.
|
|
|
|
bad-multi-none-block_1.lzma has wrong Uncompressed Size in the first
|
|
Data Block. A sophisticated decoder should detect this error before
|
|
producing any output, because it can see that the Uncompressed Size
|
|
doesn't match with the Index in Header Metadata Block; all Multi-Block
|
|
decoders must detect the file as corrupt at some point.
|
|
|
|
bad-multi-none-block_2.lzma has too big Compressed Size in the first
|
|
Data Block. A sophisticated decoder may be able to detect the file as
|
|
corrupt before producing any output, because Comrpessed Size + size
|
|
of Block Header exceed the Total Size stored in Index in Header
|
|
Metadata Block. A sophisticated decoder should be able to detect the
|
|
error before the end of the first Data Block; all Multi-Block decoders
|
|
must detect the file as corrupt at some point.
|
|
|
|
bad-multi-none-block_3.lzma has only the Compressed Size field in the
|
|
Block Header of the second Data Block and EOPM isn't used.
|
|
|
|
|
|
2.3. Malicious Files
|
|
|
|
malicious-single-subblock31-slow.lzma requires quite a bit of CPU time
|
|
per decoded byte. It contains LZMA compressed Subblock filter data that
|
|
has as much Padding as the specification allows. LZMA is also used as
|
|
a Subfilter, to further slowdown the decoder. Every Subfilter instance
|
|
produces only one byte of output. If you can create a file that wastes
|
|
notably more CPU cycles than this file, please contact Lasse Collin.
|
|
|
|
malicious-single-subblock-256MiB.lzma is a tiny file that produces
|
|
256 MiB of output. It uses Subblock filter's run-length encoding
|
|
to achieve this.
|
|
|
|
malicious-single-subblock-64PiB.lzma is a tiny file that produces
|
|
64 PiB of output (if you have patience to wait). This is done by
|
|
chaining two Subblock filters and using their run-length encoders.
|
|
|
|
malicious-multi-metadata-64PiB.lzma is like
|
|
malicious-single-subblock-64PiB.lzma but the huge amount of output
|
|
is in a Metadata Block. Trying to decode this file may take years
|
|
unless the decoder catches that the Metadata has unreasonable size.
|
|
|