Commit 4f9395b1 authored Feb 09, 2019 by Coly Li Committed by Greg Kroah-Hartman Apr 05, 2019

bcache: fix input overflow to cache set sysfs file io_error_halflife



[ Upstream commit a91fbda49f746119828f7e8ad0f0aa2ab0578f65 ]

Cache set sysfs entry io_error_halflife is used to set c->error_decay.
c->error_decay is in type unsigned int, and it is converted by
strtoul_or_return(), therefore overflow to c->error_decay is possible
for a large input value.

This patch fixes the overflow by using strtoul_safe_clamp() to convert
input string to an unsigned long value in range [0, UINT_MAX], then
divides by 88 and set it to c->error_decay.

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 49145924

drivers/md/bcache/sysfs.c

+11 −2

Original line number	Diff line number	Diff line
		@@ -645,8 +645,17 @@ STORE(__bch_cache_set)
		c->error_limit = strtoul_or_return(buf) << IO_ERROR_SHIFT;

		/* See count_io_errors() for why 88 */
		if (attr == &sysfs_io_error_halflife)
		c->error_decay = strtoul_or_return(buf) / 88;
		if (attr == &sysfs_io_error_halflife) {
		unsigned long v = 0;
		ssize_t ret;

		ret = strtoul_safe_clamp(buf, v, 0, UINT_MAX);
		if (!ret) {
		c->error_decay = v / 88;
		return size;
		}
		return ret;
		}

		sysfs_strtoul(journal_delay_ms, c->journal_delay_ms);
		sysfs_strtoul(verify, c->verify);