4.14-stable review patch. If anyone has any objections, please let me know.
------------------
[ 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 <col...@suse.de>
Signed-off-by: Jens Axboe <ax...@kernel.dk>
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
drivers/md/bcache/sysfs.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/drivers/md/bcache/sysfs.c b/drivers/md/bcache/sysfs.c
index 5d81cd06af00..43ff7fbcbc7c 100644
--- a/drivers/md/bcache/sysfs.c
+++ b/drivers/md/bcache/sysfs.c
@@ -660,8 +660,17 @@ 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);
--
2.19.1
