From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sasha Levin Subject: [PATCH AUTOSEL 4.4 40/63] bcache: fix input overflow to sequential_cutoff Date: Wed, 27 Mar 2019 14:23:00 -0400 Message-ID: <20190327182323.18577-40-sashal@kernel.org> References: <20190327182323.18577-1-sashal@kernel.org> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20190327182323.18577-1-sashal@kernel.org> Sender: linux-kernel-owner@vger.kernel.org To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Coly Li , Jens Axboe , Sasha Levin , linux-bcache@vger.kernel.org List-Id: linux-bcache@vger.kernel.org From: Coly Li [ Upstream commit 8c27a3953e92eb0b22dbb03d599f543a05f9574e ] People may set sequential_cutoff of a cached device via sysfs file, but current code does not check input value overflow. E.g. if value 4294967295 (UINT_MAX) is written to file sequential_cutoff, its value is 4GB, but if 4294967296 (UINT_MAX + 1) is written into, its value will be 0. This is an unexpected behavior. This patch replaces d_strtoi_h() by sysfs_strtoul_clamp() to convert input string to unsigned integer value, and limit its range in [0, UINT_MAX]. Then the input overflow can be fixed. Signed-off-by: Coly Li Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- 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 87daccbbc61b..463ce6757338 100644 --- a/drivers/md/bcache/sysfs.c +++ b/drivers/md/bcache/sysfs.c @@ -215,7 +215,9 @@ STORE(__cached_dev) d_strtoul(writeback_rate_d_term); d_strtoul_nonzero(writeback_rate_p_term_inverse); - d_strtoi_h(sequential_cutoff); + sysfs_strtoul_clamp(sequential_cutoff, + dc->sequential_cutoff, + 0, UINT_MAX); d_strtoi_h(readahead); if (attr == &sysfs_clear_stats) -- 2.19.1