renegade-project/linux-next
2
0
Fork 0
mirror of https://github.com/edk2-porting/linux-next.git synced 2024-11-24 10:34:57 +08:00
Code

block, bfq: fix uaf for 'stable_merge_bfqq'

Browse Source 
Before commit fd571df0ac ("block, bfq: turn bfqq_data into an array
in bfq_io_cq"), process reference is read before bfq_put_stable_ref(),
and it's safe if bfq_put_stable_ref() put the last reference, because
process reference will be 0 and 'stable_merge_bfqq' won't be accessed
in this case. However, the commit changed the order and  will cause
uaf for 'stable_merge_bfqq'.

In order to emphasize that bfq_put_stable_ref() can drop the last
reference, fix the problem by moving bfq_put_stable_ref() to the end of
bfq_setup_stable_merge().

Fixes: fd571df0ac ("block, bfq: turn bfqq_data into an array in bfq_io_cq")
Reported-and-tested-by: Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Link: https://lore.kernel.org/linux-block/20230307071448.rzihxbm4jhbf5krj@shindev/
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Yu Kuai 2023-03-08 10:32:08 +08:00 committed by Jens Axboe
parent e33062213f
commit e2f2a39452
1 changed files with 9 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
block/bfq-iosched.c
View File

@ -2854,11 +2854,11 @@ bfq_setup_stable_merge(struct bfq_data *bfqd, struct bfq_queue *bfqq,
{
int proc_ref = min(bfqq_process_refs(bfqq),
bfqq_process_refs(stable_merge_bfqq));
struct bfq_queue *new_bfqq;
struct bfq_queue *new_bfqq = NULL;
if (idling_boosts_thr_without_issues(bfqd, bfqq) ||
proc_ref == 0)
return NULL;
bfqq_data->stable_merge_bfqq = NULL;
if (idling_boosts_thr_without_issues(bfqd, bfqq) || proc_ref == 0)
goto out;
/* next function will take at least one ref */
new_bfqq = bfq_setup_merge(bfqq, stable_merge_bfqq);
@ -2873,6 +2873,11 @@ bfq_setup_stable_merge(struct bfq_data *bfqd, struct bfq_queue *bfqq,
new_bfqq_data->stably_merged = true;
}
}
out:
/* deschedule stable merge, because done or aborted here */
bfq_put_stable_ref(stable_merge_bfqq);
return new_bfqq;
}
@ -2933,11 +2938,6 @@ bfq_setup_cooperator(struct bfq_data *bfqd, struct bfq_queue *bfqq,
struct bfq_queue *stable_merge_bfqq =
bfqq_data->stable_merge_bfqq;
/* deschedule stable merge, because done or aborted here */
bfq_put_stable_ref(stable_merge_bfqq);
bfqq_data->stable_merge_bfqq = NULL;
return bfq_setup_stable_merge(bfqd, bfqq,
stable_merge_bfqq,
bfqq_data);