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| author | Coly Li <colyli@suse.de> | 2019-02-09 07:53:05 +0300 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2019-02-09 17:18:32 +0300 |
| commit | c3b75a2199cdbfc1c335155fe143d842604b1baa (patch) | |
| tree | 320acc2ba84a2f93a34e9039a75ea54d216dfcc0 /drivers/md | |
| parent | 369d21a73a241682de019ac5c5209ce3ec627743 (diff) | |
| download | linux-c3b75a2199cdbfc1c335155fe143d842604b1baa.tar.xz | |
bcache: fix potential div-zero error of writeback_rate_i_term_inverse
dc->writeback_rate_i_term_inverse can be set via sysfs interface. It is
in type unsigned int, and convert from input string by d_strtoul(). The
problem is d_strtoul() does not check valid range of the input, if
4294967296 is written into sysfs file writeback_rate_i_term_inverse,
an overflow of unsigned integer will happen and value 0 is set to
dc->writeback_rate_i_term_inverse.
In writeback.c:__update_writeback_rate(), there are following lines of
code,
integral_scaled = div_s64(dc->writeback_rate_integral,
dc->writeback_rate_i_term_inverse);
If dc->writeback_rate_i_term_inverse is set to 0 via sysfs interface,
a div-zero error might be triggered in the above code.
Therefore we need to add a range limitation in the sysfs interface,
this is what this patch does, use sysfs_stroul_clamp() to replace
d_strtoul() and restrict the input range in [1, UINT_MAX].
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'drivers/md')
| -rw-r--r-- | drivers/md/bcache/sysfs.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/md/bcache/sysfs.c b/drivers/md/bcache/sysfs.c index e4519326594f..0fad46d3a8bd 100644 --- a/drivers/md/bcache/sysfs.c +++ b/drivers/md/bcache/sysfs.c @@ -302,7 +302,9 @@ STORE(__cached_dev) sysfs_strtoul_clamp(writeback_rate_update_seconds, dc->writeback_rate_update_seconds, 1, WRITEBACK_RATE_UPDATE_SECS_MAX); - d_strtoul(writeback_rate_i_term_inverse); + sysfs_strtoul_clamp(writeback_rate_i_term_inverse, + dc->writeback_rate_i_term_inverse, + 1, UINT_MAX); d_strtoul_nonzero(writeback_rate_p_term_inverse); d_strtoul_nonzero(writeback_rate_minimum); |