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2014-09-28lzo: check for length overrun in variable length encoding.Willy Tarreau1-6/+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>
2014-09-28Revert "lzo: properly check for overruns"Willy Tarreau1-41/+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>
2014-06-23lzo: properly check for overrunsGreg Kroah-Hartman1-21/+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>
2013-02-20lib/lzo: Update LZO compression to current upstream versionMarkus F.X.J. Oberhumer1-184/+166
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>
2013-02-20lib/lzo: Rename lzo1x_decompress.c to lzo1x_decompress_safe.cMarkus F.X.J. Oberhumer1-0/+255
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>