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bcache: fix input overflow to cache set sysfs file io_error_halflife 

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>
hifive-unleashed-5.1
Coly Li 2019-02-09 12:53:10 +08:00 committed by Jens Axboe
parent b15008403b
commit a91fbda49f
1 changed files with 11 additions and 2 deletions
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13
drivers/md/bcache/sysfs.c
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@ -804,8 +804,17 @@ STORE(__bch_cache_set)
sysfs_strtoul_clamp(io_error_limit, c->error_limit, 0, UINT_MAX);
/* 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;
}
if (attr == &sysfs_io_disable) {
v = strtoul_or_return(buf);