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* lzo: check for length overrun in variable length encoding.Willy Tarreau2014-09-281-6/+37
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | This fix ensures that we never meet an integer overflow while adding 255 while parsing a variable length encoding. It works differently from commit 206a81c ("lzo: properly check for overruns") because instead of ensuring that we don't overrun the input, which is tricky to guarantee due to many assumptions in the code, it simply checks that the cumulated number of 255 read cannot overflow by bounding this number. The MAX_255_COUNT is the maximum number of times we can add 255 to a base count without overflowing an integer. The multiply will overflow when multiplying 255 by more than MAXINT/255. The sum will overflow earlier depending on the base count. Since the base count is taken from a u8 and a few bits, it is safe to assume that it will always be lower than or equal to 2*255, thus we can always prevent any overflow by accepting two less 255 steps. This patch also reduces the CPU overhead and actually increases performance by 1.1% compared to the initial code, while the previous fix costs 3.1% (measured on x86_64). The fix needs to be backported to all currently supported stable kernels. Reported-by: Willem Pinckaers <willem@lekkertech.net> Cc: "Don A. Bailey" <donb@securitymouse.com> Cc: stable <stable@vger.kernel.org> Signed-off-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Revert "lzo: properly check for overruns"Willy Tarreau2014-09-281-41/+21
| | | | | | | | | | | | | | This reverts commit 206a81c ("lzo: properly check for overruns"). As analysed by Willem Pinckaers, this fix is still incomplete on certain rare corner cases, and it is easier to restart from the original code. Reported-by: Willem Pinckaers <willem@lekkertech.net> Cc: "Don A. Bailey" <donb@securitymouse.com> Cc: stable <stable@vger.kernel.org> Signed-off-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* lzo: properly check for overrunsGreg Kroah-Hartman2014-06-231-21/+41
| | | | | | | | | | | The lzo decompressor can, if given some really crazy data, possibly overrun some variable types. Modify the checking logic to properly detect overruns before they happen. Reported-by: "Don A. Bailey" <donb@securitymouse.com> Tested-by: "Don A. Bailey" <donb@securitymouse.com> Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* lib/lzo: Update LZO compression to current upstream versionMarkus F.X.J. Oberhumer2013-02-203-336/+387
| | | | | | | | | This commit updates the kernel LZO code to the current upsteam version which features a significant speed improvement - benchmarking the Calgary and Silesia test corpora typically shows a doubled performance in both compression and decompression on modern i386/x86_64/powerpc machines. Signed-off-by: Markus F.X.J. Oberhumer <markus@oberhumer.com>
* lib/lzo: Rename lzo1x_decompress.c to lzo1x_decompress_safe.cMarkus F.X.J. Oberhumer2013-02-202-1/+1
| | | | | | | | Rename the source file to match the function name and thereby also make room for a possible future even slightly faster "non-safe" decompressor version. Signed-off-by: Markus F.X.J. Oberhumer <markus@oberhumer.com>
* lib: add support for LZO-compressed kernelsAlbin Tonnerre2010-01-111-3/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch series adds generic support for creating and extracting LZO-compressed kernel images, as well as support for using such images on the x86 and ARM architectures, and support for creating and using LZO-compressed initrd and initramfs images. Russell King said: : Testing on a Cortex A9 model: : - lzo decompressor is 65% of the time gzip takes to decompress a kernel : - lzo kernel is 9% larger than a gzip kernel : : which I'm happy to say confirms your figures when comparing the two. : : However, when comparing your new gzip code to the old gzip code: : - new is 99% of the size of the old code : - new takes 42% of the time to decompress than the old code : : What this means is that for a proper comparison, the results get even better: : - lzo is 7.5% larger than the old gzip'd kernel image : - lzo takes 28% of the time that the old gzip code took : : So the expense seems definitely worth the effort. The only reason I : can think of ever using gzip would be if you needed the additional : compression (eg, because you have limited flash to store the image.) : : I would argue that the default for ARM should therefore be LZO. This patch: The lzo compressor is worse than gzip at compression, but faster at extraction. Here are some figures for an ARM board I'm working on: Uncompressed size: 3.24Mo gzip 1.61Mo 0.72s lzo 1.75Mo 0.48s So for a compression ratio that is still relatively close to gzip, it's much faster to extract, at least in that case. This part contains: - Makefile routine to support lzo compression - Fixes to the existing lzo compressor so that it can be used in compressed kernels - wrapper around the existing lzo1x_decompress, as it only extracts one block at a time, while we need to extract a whole file here - config dialog for kernel compression [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: cleanup] Signed-off-by: Albin Tonnerre <albin.tonnerre@free-electrons.com> Tested-by: Wu Zhangjin <wuzhangjin@gmail.com> Acked-by: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Tested-by: Russell King <rmk@arm.linux.org.uk> Acked-by: Russell King <rmk@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* lzo: use get/put_unaligned_* helpersHarvey Harrison2008-07-251-4/+2
| | | | | | | Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Acked-by: Richard Purdie <rpurdie@rpsys.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* lzo: fix typo in decompressorHarvey Harrison2008-04-111-1/+1
| | | | | | | | | Shift of a LE value seems strange, probably meant to shift the cpu-order variable as in the prvious section of the switch statement. Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Acked-by: Richard Purdie <rpurdie@rpsys.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* lzo: add some missing castsRichard Purdie2007-08-011-3/+3
| | | | | | | | | | Add some casts to the LZO compression algorithm after they were removed during cleanup and shouldn't have been. Signed-off-by: Richard Purdie <rpurdie@openedhand.com> Cc: Edward Shishkin <edward@namesys.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Add LZO1X algorithm to the kernelRichard Purdie2007-07-114-0/+528
This is a hybrid version of the patch to add the LZO1X compression algorithm to the kernel. Nitin and myself have merged the best parts of the various patches to form this version which we're both happy with (and are jointly signing off). The performance of this version is equivalent to the original minilzo code it was based on. Bytecode comparisons have also been made on ARM, i386 and x86_64 with favourable results. There are several users of LZO lined up including jffs2, crypto and reiser4 since its much faster than zlib. Signed-off-by: Nitin Gupta <nitingupta910@gmail.com> Signed-off-by: Richard Purdie <rpurdie@openedhand.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>