From dab71b2db98dcdd4657d151b01a7be88ce10f9d1 Mon Sep 17 00:00:00 2001
From: Coly Li <colyli@suse.de>
Date: Sat, 9 Feb 2019 12:53:07 +0800
Subject: [PATCH] bcache: fix input overflow to writeback_rate_minimum
Git-commit: dab71b2db98dcdd4657d151b01a7be88ce10f9d1
Patch-mainline: v5.1-rc1
References: bsc#1130972

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>

---
 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 c6677c93e368..d292eb757ac4 100644
--- 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);
 
-- 
2.16.4