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author | Dave Rodgman <dave.rodgman@arm.com> | 2020-06-12 03:34:54 +0300 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-06-17 17:40:28 +0300 |
commit | d4904b38ea45a2b8ff98fa6fa7a6f6d761306d27 (patch) | |
tree | cdc5d1306f442a5a416d68734438d22890998f99 /drivers/perf | |
parent | 07ffdf0d984b0b5631bce3074d3aefdd673d69fe (diff) | |
download | linux-d4904b38ea45a2b8ff98fa6fa7a6f6d761306d27.tar.xz |
lib/lzo: fix ambiguous encoding bug in lzo-rle
commit b5265c813ce4efbfa2e46fd27cdf9a7f44a35d2e upstream.
In some rare cases, for input data over 32 KB, lzo-rle could encode two
different inputs to the same compressed representation, so that
decompression is then ambiguous (i.e. data may be corrupted - although
zram is not affected because it operates over 4 KB pages).
This modifies the compressor without changing the decompressor or the
bitstream format, such that:
- there is no change to how data produced by the old compressor is
decompressed
- an old decompressor will correctly decode data from the updated
compressor
- performance and compression ratio are not affected
- we avoid introducing a new bitstream format
In testing over 12.8M real-world files totalling 903 GB, three files
were affected by this bug. I also constructed 37M semi-random 64 KB
files totalling 2.27 TB, and saw no affected files. Finally I tested
over files constructed to contain each of the ~1024 possible bad input
sequences; for all of these cases, updated lzo-rle worked correctly.
There is no significant impact to performance or compression ratio.
Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Dave Rodgman <dave.rodgman@arm.com>
Cc: Willy Tarreau <w@1wt.eu>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Markus F.X.J. Oberhumer <markus@oberhumer.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Chao Yu <yuchao0@huawei.com>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20200507100203.29785-1-dave.rodgman@arm.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/perf')
0 files changed, 0 insertions, 0 deletions