bcache: fix input overflow to writeback_rate_minimum

dc->writeback_rate_minimum is type unsigned integer variable, it is set
via sysfs interface, and converte from input string to unsigned integer
by d_strtoul_nonzero(). When the converted input value is larger than
UINT_MAX, overflow to unsigned integer happens.

This patch fixes the overflow by using sysfs_strotoul_clamp() to
convert input string and limit the value in range [1, UINT_MAX], then
the overflow can be avoided.

Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/md/bcache/sysfs.c b/drivers/md/bcache/sysfs.c
index c6677c9..d292eb7 100644 (file)
--- a/drivers/md/bcache/sysfs.c
+++ b/drivers/md/bcache/sysfs.c
@@ -308,7 +308,9 @@ STORE(__cached_dev)
        sysfs_strtoul_clamp(writeback_rate_p_term_inverse,
                            dc->writeback_rate_p_term_inverse,
                            1, UINT_MAX);
-       d_strtoul_nonzero(writeback_rate_minimum);
+       sysfs_strtoul_clamp(writeback_rate_minimum,
+                           dc->writeback_rate_minimum,
+                           1, UINT_MAX);
 
        sysfs_strtoul_clamp(io_error_limit, dc->error_limit, 0, INT_MAX);