liblzma guarantees that the product of the allocation size arguments
will fit in size_t.
Putting the pre-increment in the if-statement was clearly wrong
although in practice it didn't matter here as the function is
called only a couple of times.
A few lines were reordered, a few ARRAY_SIZE were changed to sizeof,
and a few uint32_t were changed to size_t. No real functional changes
were intended.
While the backdoor was inactive (and thus harmless) without inserting
a small trigger code into the build system when the source package was
created, it's good to remove this anyway:
- The executable payloads were embedded as binary blobs in
the test files. This was a blatant violation of the
Debian Free Software Guidelines.
- On machines that see lots bots poking at the SSH port, the backdoor
noticeably increased CPU load, resulting in degraded user experience
and thus overwhelmingly negative user feedback.
- The maintainer who added the backdoor has disappeared.
- Backdoors are bad for security.
This reverts the following without making any other changes:
6e636819 Tests: Update two test files.
a3a29bbd Tests: Test --single-stream can decompress bad-3-corrupt_lzma2.xz.
0b4ccc91 Tests: Update RISC-V test files.
8c9b8b20 liblzma: Fix typos in crc32_fast.c and crc64_fast.c.
82ecc538 liblzma: Fix false Valgrind error report with GCC.
cf44e4b7 Tests: Add a few test files.
3060e107 Tests: Use smaller dictionary size in RISC-V test files.
e2870db5 Tests: Add two RISC-V Filter test files.
The RISC-V test files also have real content that tests the filter
but the real content would fit into much smaller files. A generator
program would need to be available as well.
Thanks to Andres Freund for finding and reporting it and making
it public quickly so others could act without a delay.
See: https://www.openwall.com/lists/oss-security/2024/03/29/4
The original files were generated with random local to my machine.
To better reproduce these files in the future, a constant seed was used
to recreate these files.
In contrast to Automake, skipping of this test when decoders
are disabled is handled at CMake side instead of test_scripts.sh
because CMake-build doesn't create config.h.
These test files achieve 100% code coverage in
src/liblzma/simple/riscv.c. They contain all of the instructions that
should be filtered and a few cases that should not.
Since GCC version 10, GCC no longer complains about simple implicit
integer conversions with Arithmetic operators.
For instance:
uint8_t a = 5;
uint32_t b = a + 5;
Give a warning on GCC 9 and earlier but this:
uint8_t a = 5;
uint32_t b = (a + 5) * 2;
Gives a warning with GCC 10+.
Most of these fixes are small typos and tweaks. A few were caused by bad
advice from me. Here is the summary of what is changed:
- Author line edits
- Small comment changes/additions
- Using the return value in the error messages in the fuzz targets'
coder initialization code
- Removed fuzz_encode_stream.options. This set a max length, which may
prevent some worthwhile code paths from being properly exercised.
- Removed the max_len option from fuzz_decode_stream.options for the
same reason as fuzz_encode_stream. The alone decoder fuzz target still
has this restriction.
- Altered the dictionary contents for fuzz_lzma.dict. Instead of keeping
the properties static and varying the dictionary size, the properties
are varied and the dictionary size is kept small. The dictionary size
doesn't have much impact on the code paths but the properties do.
Closes: https://github.com/tukaani-project/xz/pull/73
This fuzz target handles .xz stream encoding. The first byte of input
is used to dynamically set the preset level in order to increase the
fuzz coverage of complex critical code paths.
This fuzz target that handles LZMA alone decoding. A new fuzz
dictionary .dict was also created with common LZMA header values to
help speed up the discovery of valid headers.
All .c files can be built as separate fuzz targets. This simplifies
the Makefile by allowing us to use wildcards instead of having a
Makefile target for each fuzz target.
Lasse Collin
Jia Tan
Maksym Vatsyk