Commit c7b687eb authored Feb 09, 2019 by Coly Li Committed by Greg Kroah-Hartman Apr 05, 2019

bcache: fix input overflow to sequential_cutoff



[ 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 <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>

parent 16975f04

drivers/md/bcache/sysfs.c

+3 −1

Original line number	Original line	Diff line number	Diff line
	@@ -295,7 +295,9 @@ STORE(__cached_dev)
	dc->io_disable = v ? 1 : 0;		dc->io_disable = v ? 1 : 0;
	}		}

	d_strtoi_h(sequential_cutoff);		sysfs_strtoul_clamp(sequential_cutoff,
			dc->sequential_cutoff,
			0, UINT_MAX);
	d_strtoi_h(readahead);		d_strtoi_h(readahead);

	if (attr == &sysfs_clear_stats)		if (attr == &sysfs_clear_stats)