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2021-10-19lib/xz, lib/decompress_unxz.c: Fix spelling in commentsLasse Collin
uncompressible -> incompressible non-splitted -> non-split Link: https://lore.kernel.org/r/20211010213145.17462-6-xiang@kernel.org Signed-off-by: Lasse Collin <lasse.collin@tukaani.org> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2021-10-19lib/xz: Add MicroLZMA decoderLasse Collin
MicroLZMA is a yet another header format variant where the first byte of a raw LZMA stream (without the end of stream marker) has been replaced with a bitwise-negation of the lc/lp/pb properties byte. MicroLZMA was created to be used in EROFS but can be used by other things too where wasting minimal amount of space for headers is important. This is implemented using most of the LZMA2 code as is so the amount of new code is small. The API has a few extra features compared to the XZ decoder. On the other hand, the API lacks XZ_BUF_ERROR support which is important to take into account when using this API. MicroLZMA doesn't support BCJ filters. In theory they could be added later as there are many unused/reserved values for the first byte of the compressed stream but in practice it is somewhat unlikely to happen due to a few implementation reasons. Link: https://lore.kernel.org/r/20211010213145.17462-5-xiang@kernel.org Signed-off-by: Lasse Collin <lasse.collin@tukaani.org> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2021-10-19lib/xz: Move s->lzma.len = 0 initialization to lzma_reset()Lasse Collin
It's a more logical place even if the resetting needs to be done only once per LZMA2 stream (if lzma_reset() called in the middle of an LZMA2 stream, .len will already be 0). Link: https://lore.kernel.org/r/20211010213145.17462-4-xiang@kernel.org Signed-off-by: Lasse Collin <lasse.collin@tukaani.org> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2021-10-19lib/xz: Avoid overlapping memcpy() with invalid input with in-place ↵Lasse Collin
decompression With valid files, the safety margin described in lib/decompress_unxz.c ensures that these buffers cannot overlap. But if the uncompressed size of the input is larger than the caller thought, which is possible when the input file is invalid/corrupt, the buffers can overlap. Obviously the result will then be garbage (and usually the decoder will return an error too) but no other harm will happen when such an over-run occurs. This change only affects uncompressed LZMA2 chunks and so this should have no effect on performance. Link: https://lore.kernel.org/r/20211010213145.17462-2-xiang@kernel.org Signed-off-by: Lasse Collin <lasse.collin@tukaani.org> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2021-07-01lib/decompressors: fix spelling mistakesZhen Lei
Fix some spelling mistakes in comments: sentinal ==> sentinel compresed ==> compressed dependeny ==> dependency immediatelly ==> immediately dervied ==> derived splitted ==> split nore ==> not independed ==> independent asumed ==> assumed Link: https://lkml.kernel.org/r/20210604085656.12257-1-thunder.leizhen@huawei.com Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-11-18Revert "lib: Revert use of fallthrough pseudo-keyword in lib/"Nick Desaulniers
This reverts commit 6a9dc5fd6170 ("lib: Revert use of fallthrough pseudo-keyword in lib/") Now that we can build arch/powerpc/boot/ free of -Wimplicit-fallthrough, re-enable these fixes for lib/. Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nathan Chancellor <natechancellor@gmail.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org> Reviewed-by: Miguel Ojeda <ojeda@kernel.org> Link: https://github.com/ClangBuiltLinux/linux/issues/236 Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
2020-08-24lib: Revert use of fallthrough pseudo-keyword in lib/Gustavo A. R. Silva
The following build error for powerpc64 was reported by Nathan Chancellor: "$ scripts/config --file arch/powerpc/configs/powernv_defconfig -e KERNEL_XZ $ make -skj"$(nproc)" ARCH=powerpc CROSS_COMPILE=powerpc64le-linux- distclean powernv_defconfig zImage ... In file included from arch/powerpc/boot/../../../lib/decompress_unxz.c:234, from arch/powerpc/boot/decompress.c:38: arch/powerpc/boot/../../../lib/xz/xz_dec_stream.c: In function 'dec_main': arch/powerpc/boot/../../../lib/xz/xz_dec_stream.c:586:4: error: 'fallthrough' undeclared (first use in this function) 586 | fallthrough; | ^~~~~~~~~~~ This will end up affecting distribution configurations such as Debian and OpenSUSE according to my testing. I am not sure what the solution is, the PowerPC wrapper does not set -D__KERNEL__ so I am not sure that compiler_attributes.h can be safely included." In order to avoid these sort of problems, it seems that the best solution is to use /* fall through */ comments instead of the fallthrough pseudo-keyword macro in lib/, for now. Reported-by: Nathan Chancellor <natechancellor@gmail.com> Fixes: df561f6688fe ("treewide: Use fallthrough pseudo-keyword") Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> Reviewed-and-tested-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-23treewide: Use fallthrough pseudo-keywordGustavo A. R. Silva
Replace the existing /* fall through */ comments and its variants with the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary fall-through markings when it is the case. [1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
2020-08-12lib/: replace HTTP links with HTTPS onesAlexander A. Klimov
Rationale: Reduces attack surface on kernel devs opening the links for MITM as HTTPS traffic is much harder to manipulate. Signed-off-by: Alexander A. Klimov <grandmaster@al2klimov.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Coly Li <colyli@suse.de> [crc64.c] Link: http://lkml.kernel.org/r/20200726112154.16510-1-grandmaster@al2klimov.de Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-11-15lib/xz: fix XZ_DYNALLOC to avoid useless memory reallocationsLasse Collin
s->dict.allocated was initialized to 0 but never set after a successful allocation, thus the code always thought that the dictionary buffer has to be reallocated. Link: http://lkml.kernel.org/r/20191104185107.3b6330df@tukaani.org Signed-off-by: Lasse Collin <lasse.collin@tukaani.org> Reported-by: Yu Sun <yusun2@cisco.com> Acked-by: Daniel Walker <danielwa@cisco.com> Cc: "Yixia Si (yisi)" <yisi@cisco.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-04lib/xz: add comments for the intentionally missing break statementsLasse Collin
Signed-off-by: Lasse Collin <lasse.collin@tukaani.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-02XZ decompressor: Fix decoding of empty LZMA2 streamsLasse Collin
The old code considered valid empty LZMA2 streams to be corrupt. Note that a typical empty .xz file has no LZMA2 data at all, and thus most .xz files having no uncompressed data are handled correctly even without this fix. Signed-off-by: Lasse Collin <lasse.collin@tukaani.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-13decompressors: add XZ decompressor moduleLasse Collin
In userspace, the .lzma format has become mostly a legacy file format that got superseded by the .xz format. Similarly, LZMA Utils was superseded by XZ Utils. These patches add support for XZ decompression into the kernel. Most of the code is as is from XZ Embedded <http://tukaani.org/xz/embedded.html>. It was written for the Linux kernel but is usable in other projects too. Advantages of XZ over the current LZMA code in the kernel: - Nice API that can be used by other kernel modules; it's not limited to kernel, initramfs, and initrd decompression. - Integrity check support (CRC32) - BCJ filters improve compression of executable code on certain architectures. These together with LZMA2 can produce a few percent smaller kernel or Squashfs images than plain LZMA without making the decompression slower. This patch: Add the main decompression code (xz_dec), testing module (xz_dec_test), wrapper script (xz_wrap.sh) for the xz command line tool, and documentation. The xz_dec module is enough to have a usable XZ decompressor e.g. for Squashfs. Signed-off-by: Lasse Collin <lasse.collin@tukaani.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Alain Knaff <alain@knaff.lu> Cc: Albin Tonnerre <albin.tonnerre@free-electrons.com> Cc: Phillip Lougher <phillip@lougher.demon.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>