When the output buffer is `NULL` with size 0, but the frame content size
is non-zero, we will write to the NULL pointer because our bounds check
underflowed.
This was exposed by a recent PR that allowed an empty frame into the
single-pass shortcut in streaming mode.
* Fix the bug.
* Fix another NULL dereference in zstd-v1.
* Overflow checks in 32-bit mode.
* Add a dedicated test.
* Expose the bug in the dedicated simple_decompress fuzzer.
* Switch all mallocs in fuzzers to return NULL for size=0.
* Fix a new timeout in a fuzzer.
Neither clang nor gcc show a decompression speed regression on x86-64.
On x86-32 clang is slightly positive and gcc loses 2.5% of speed.
Credit to OSS-Fuzz.
It's complaining about the `memcpy`s, saying:
"warning C4090: 'function': different 'const' qualifiers"
Let's try explicitly casting to the argument types...
Fixes:
Enable RLE blocks for superblock mode
Fix the limitation that the literals block must shrink. Instead, when we're within 200 bytes of the next header byte size, we will just use the next one up. That way we should (almost?) always have space for the table.
Remove the limitation that the first sub-block MUST have compressed literals and be compressed. Now one sub-block MUST be compressed (otherwise we fall back to raw block which is okay, since that is streamable). If no block has compressed literals that is okay, we will fix up the next Huffman table.
Handle the case where the last sub-block is uncompressed (maybe it is very small). Before it would skip superblock in this case, now we allow the last sub-block to be uncompressed. To do this we need to regenerate the correct repcodes.
Respect disableLiteralsCompression in superblock mode
Fix superblock mode to handle a block consisting of only compressed literals
Fix a off by 1 error in superblock mode that disabled it whenever there were last literals
Fix superblock mode with long literals/matches (> 0xFFFF)
Allow superblock mode to repeat Huffman tables
Respect ZSTD_minGain().
Tests:
Simple check for the condition in #2096.
When the simple_round_trip fuzzer enables superblock mode, it checks that the compressed size isn't expanded too much.
Remaining limitations:
O(targetCBlockSize^2) because we recompute statistics every sequence
Unable to split literals of length > targetCBlockSize into multiple sequences
Refuses to generate sub-blocks that don't shrink the compressed data, so we could end up with large sub-blocks. We should emit those sections as uncompressed blocks instead.
...
Fixes#2096
* adding long support for patch-from
* adding refPrefix to dictionary_decompress
* adding refPrefix to dictionary_loader
* conversion nit
* triggering log mode on chainLog < fileLog and removing old threshold
* adding refPrefix to dictionary_round_trip
* adding docs
* adding enableldm + forceWindow test for dict
* separate patch-from logic into FIO_adjustParamsForPatchFromMode
* moving memLimit adjustment to outside ifdefs (need for decomp)
* removing refPrefix gate on dictionary_round_trip
* rebase on top of dev refPrefix change
* making sure refPrefx + ldm is < 1% of srcSize
* combining notes for patch-from
* moving memlimit logic inside fileio.c
* adding display for optimal parser and long mode trigger
* conversion nit
* fuzzer found heap-overflow fix
* another conversion nit
* moving FIO_adjustMemLimitForPatchFromMode outside ifndef
* making params immutable
* moving memLimit update before createDictBuffer call
* making maxSrcSize unsigned long long
* making dictSize and maxSrcSize params unsigned long long
* error on files larger than 4gb
* extend refPrefix test to include round trip
* conversion to size_t
* making sure ldm is at least 10x better
* removing break
* including zstd_compress_internal and removing redundant macros
* exposing ZSTD_cycleLog()
* using cycleLog instead of chainLog
* add some more docs about user optimizations
* formatting
playTests.sh didn't work when `ZSTD_BIN` or `DATAGEN_BIN` had a space in
the path name. This happens for me because I split the cmake build
directory by compiler name, like "Clang 9.0.0".
The fix is to replace all instances of `$ZSTD` with the `zstd()`
function, and the replace `$DATAGEN` with `datagen()`. This will allow
us to change how we call zstd/datagen in the future without having to
change every callsite.
Tests all `.h`, `.c`, `.py`, and `Makefile` files for valid copyright
and license lines. Excludes a small number of exceptions (threading, and
divsufsort).
* Copyright does not contains `present`
* Copyright contains `Facebook, Inc`
* Copyright contains the current year
* License contains exactly the lines we expect
* All copyright lines now have -2020 instead of -present
* All copyright lines include "Facebook, Inc"
* All licenses are now standardized
The copyright in `threading.{h,c}` is not changed because it comes from
zstdmt.
The copyright and license of `divsufsort.{h,c}` is not changed.
* Removing symbols that are not being tested
* Removing symbols used in zstdcli, fileio, dibio and benchzstd
* Removing symbols used in zbuff and add test-zbuff to travis
* Removing remaining symbols and adding unit tests instead
* Removing symbols test entirely
* Make arugments optional and add --dict argument
* Removing accidental print statement
* Change to more likely scenario for dictionary compression benchmark
Super blocks must never violate the zstd block bound of input_size + ZSTD_blockHeaderSize. The individual sub-blocks may, but not the super block. If the superblock violates the block bound we are liable to violate ZSTD_compressBound(), which we must not do. Whenever the super block violates the block bound we instead emit an uncompressed block.
This means we increase the latency because of the single uncompressed block. I fix this by enabling streaming an uncompressed block, so the latency of an uncompressed block is 1 byte. This doesn't reduce the latency of the buffer-less API, but I don't think we really care.
* I added a test case that verifies that the decompression has 1 byte latency.
* I rely on existing zstreamtest / fuzzer / libfuzzer regression tests for correctness. During development I had several correctness bugs, and they easily caught them.
* The added assert that the superblock doesn't violate the block bound will help us discover any missed conditions (though I think I got them all).
Credit to OSS-Fuzz.
* Adding new cli endpoint --diff-from=
* Appveyor conversion nit
* Using bool set trick instead of direct set
* Removing --diff-from and only leaving --diff-from=#
* Throwing error when both dictFileName vars are set
* Clean up syntax
* Renaming diff-from to patch-from
* Revering comma separated syntax clean up
* Updating playtests with patch-from
* Uncommenting accidentally commented
* Updating remaining docs and var names to be patch-from instead of diff-from
* Constifying
* Using existing log2 function and removing newly created one
* Argument order (moving prefs to end)
* Using comma separated syntax
* Moving to outside #ifndef
* Allow zero sized buffers in `stream_decompress`. Ensure that we never have two
zero sized buffers in a row so we guarantee forwards progress.
* Make case 4 in `stream_round_trip` do a zero sized buffers call followed by
a full call to guarantee forwards progress.
* Fix `limitCopy()` in legacy decoders.
* Fix memcpy in `zstdmt_compress.c`.
Catches the bug fixed in PR #1939
The `numFiles` variable wasn't updated, so the fuzzer didn't do anything.
I did two things to fix this:
1. Remove the `numFiles` variable entirely.
2. Error if we can't open a file and print the number of files tested.
* Initial revised automated benchmarking script
* Updating nb_iterations and making loop infinite
* Allowing benchmarking params to be changed from cli
* Renaming old speed test
* Removing numpy dependency for cli
* Change filename and benchmakr on pr level
* Moving build outside loop and adding iterations param
* Moving benchmarking to seperate travis ci test
* Fixing typo and using unused variable
* Added mode labels and updated README accordingly
* Adding new mode 'current' that compraes facebook:dev against current hash
* Typo
* Reverting previous accidental diff
* Typo
* Adding frequency config variable to prevent github from blacklisting
* Added new argument for frequency of fetching new prs
* Updating documentation
* Adding fail logging for superblock flow
* Dividing by targetCBlockSize instead of blockSize
* Adding new const and using more acurate formula for nbBlocks
* Only do dstCapacity check if using superblock
* Remvoing disabling logic
* Updating test to make it catch more extreme case of previou bug
* Also updating comment
* Only taking compressEnd shortcut on non-superblock
Fixes a fuzz issue where dictionary_round_trip failed because the compressor was generating corrupt files thanks to zero weights in the table.
* Only setting loaded dict huf table to valid on non-zero
* Adding hasNoZeroWeights test to fse tables
* Forbiding nbBits != 0 when weight == 0
* Reverting the last commit
* Setting table log to 0 when weight == 0
* Small (invalid) zero weight dict test
* Small (valid) zero weight dict test
* Initializing repeatMode vars to check before zero check
* Removing FSE changes to seperate pr
* Reverting accidentally changed file
* Negating bool, using unsigned, optimization nit
/dev/null permissions were modified when using sudo rights.
This fixes this bug during decompression.
More importantly, this patch adds a test, triggered in TravisCI,
ensuring unaltered /dev/null permissions.
date(1) is used to display the last modification time of a file, which
is not supported on OpenBSD, FreeBSD and Darwin. Instead use stat(1).
Tested on OpenBSD.
* Silently skip dictionaries less than 8 bytes, unless using `ZSTD_dct_fullDict`.
This changes the compressor, which silently skips dictionaries <= 8 bytes.
* Allow repcodes that are equal to the dictionary content size, since it is in bounds.
* Adds the fuzzer
* Adds an additional `InputType` for the fuzzer
I ran the fuzzer for about 10 minutes and it found 2 bugs:
* Catches the original bug without any help
* Catches an additional bug with 8-byte dictionaries
* A copy-paste error made it so we weren't running the advanced/cdict
streaming tests with the old API.
* Clean up the old streaming tests to skip incompatible configs.
* Update `results.csv`.
The tests now catch the bug in #1787.
Compression ratio of fast strategies (levels 1 & 2)
was seriously reduced, due to accidental disabling of Literals compression.
Credit to @QrczakMK, which perfectly described the issue, and implementation details,
making the fix straightforward.
Example : initCStream with level 1 on synthetic sample P50 :
Before : 5,273,976 bytes
After : 3,154,678 bytes
ZSTD_compress (for comparison) : 3,154,550
Fix#1787.
To follow : refactor the test which was supposed to catch this issue (and failed)
* Fix `ZSTD_FRAMEHEADERSIZE_PREFIX` and `ZSTD_FRAMEHEADERSIZE_MIN` to
take a `format` parameter, so it is impossible to get the wrong size.
* Fix the places that called `ZSTD_FRAMEHEADERSIZE_PREFIX` without
taking the format into account, which is now impossible by design.
* Call `ZSTD_frameHeaderSize_internal()` with `dctx->format`.
* The added tests catch both bugs in `ZSTD_decompressFrame()`.
Fixes#1813.
* Remove the `make libFuzzer` target since it is broken and obsoleted
by `CC=clang CXX=clang++ ./fuzz.py build all --enable-fuzzer`. The
new `-fsanitize=fuzzer` is much better because it works with MSAN
by default.
* Improve the `./fuzz.py gen` command by making the input type explicit
when creating a new target.
* Update the `README` for `--enable-fuzzer`.
Fixes#1727.
