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authorColy Li <colyli@suse.de>2019-02-09 12:53:01 +0800
committerJens Axboe <axboe@kernel.dk>2019-02-09 07:18:32 -0700
commit8c27a3953e92eb0b22dbb03d599f543a05f9574e (patch)
treec114e4792522bd136d5e1785cde5e1eac8e1ad39 /drivers
parentf54478c6e226bb1540a3e58366601039dfd778e2 (diff)
downloadlinux-8c27a3953e92eb0b22dbb03d599f543a05f9574e.tar.gz
bcache: fix input overflow to sequential_cutoff
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>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/md/bcache/sysfs.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/md/bcache/sysfs.c b/drivers/md/bcache/sysfs.c
index bedd3e68fd29..96b64893f2cb 100644
--- a/drivers/md/bcache/sysfs.c
+++ b/drivers/md/bcache/sysfs.c
@@ -314,7 +314,9 @@ STORE(__cached_dev)
 		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);
 
 	if (attr == &sysfs_clear_stats)