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| author | Palash Oswal <hello@oswalpalash.com> | 2021-04-27 18:21:49 +0530 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2021-04-27 07:37:39 -0600 |
| commit | 6d042ffb598ed83e7d5623cc961d249def5b9829 (patch) | |
| tree | c6b857d10a645b11e5f3c5ebbce5acf227dc64dd /fs/io_uring.c | |
| parent | 0b8c0e7c9692cfcfa02c9052d4d53ae67901c400 (diff) | |
| download | lwn-6d042ffb598ed83e7d5623cc961d249def5b9829.tar.gz lwn-6d042ffb598ed83e7d5623cc961d249def5b9829.zip | |
io_uring: Check current->io_uring in io_uring_cancel_sqpoll
syzkaller identified KASAN: null-ptr-deref Write in
io_uring_cancel_sqpoll.
io_uring_cancel_sqpoll is called by io_sq_thread before calling
io_uring_alloc_task_context. This leads to current->io_uring being NULL.
io_uring_cancel_sqpoll should not have to deal with threads where
current->io_uring is NULL.
In order to cast a wider safety net, perform input sanitisation directly
in io_uring_cancel_sqpoll and return for NULL value of current->io_uring.
This is safe since if current->io_uring isn't set, then there's no way
for the task to have submitted any requests.
Reported-by: syzbot+be51ca5a4d97f017cd50@syzkaller.appspotmail.com
Cc: stable@vger.kernel.org
Signed-off-by: Palash Oswal <hello@oswalpalash.com>
Link: https://lore.kernel.org/r/20210427125148.21816-1-hello@oswalpalash.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'fs/io_uring.c')
| -rw-r--r-- | fs/io_uring.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c index 863420e184cf..81096f3b01ea 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -9044,6 +9044,8 @@ static void io_uring_cancel_sqpoll(struct io_sq_data *sqd) s64 inflight; DEFINE_WAIT(wait); + if (!current->io_uring) + return; WARN_ON_ONCE(!sqd || sqd->thread != current); atomic_inc(&tctx->in_idle); |