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* lzo: check for length overrun in variable length encoding.Willy Tarreau2014-12-141-6/+37
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 72cf90124e87d975d0b2114d930808c58b4c05e4 upstream. 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> Signed-off-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
* Revert "lzo: properly check for overruns"Willy Tarreau2014-12-141-41/+21
| | | | | | | | | | | | | | | | commit af958a38a60c7ca3d8a39c918c1baa2ff7b6b233 upstream. 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> Signed-off-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
* lzo: properly check for overrunsGreg Kroah-Hartman2014-07-111-21/+41
| | | | | | | | | | | | | commit 206a81c18401c0cde6e579164f752c4b147324ce upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
* lib/lzo: Update LZO compression to current upstream versionMarkus F.X.J. Oberhumer2014-07-111-184/+166
| | | | | | | | | | | | commit 8b975bd3f9089f8ee5d7bbfd798537b992bbc7e7 upstream. 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> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
* lib/lzo: Rename lzo1x_decompress.c to lzo1x_decompress_safe.cMarkus F.X.J. Oberhumer2014-07-111-0/+255
commit b6bec26cea948148a9420e7a0ac337f925de49e7 upstream. 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> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>