[PATCH 08/11] bcache: fix input overflow to writeback_rate_minimum

[Coly Li]

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 <col...@suse.de>
---
 drivers/md/bcache/sysfs.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/md/bcache/sysfs.c b/drivers/md/bcache/sysfs.c
index a5d292707698..31e41cc3c162 100644
--- a/drivers/md/bcache/sysfs.c
+++ b/drivers/md/bcache/sysfs.c
@@ -304,7 +304,9 @@ 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);
 
-- 
2.16.4