From: Palash Oswal <hello@oswalpalash.com>
To: asml.silence@gmail.com
Cc: axboe@kernel.dk, dvyukov@google.com, io-uring@vger.kernel.org,
linux-kernel@vger.kernel.org, oswalpalash@gmail.com,
syzbot+be51ca5a4d97f017cd50@syzkaller.appspotmail.com,
syzkaller-bugs@googlegroups.com,
Palash Oswal <hello@oswalpalash.com>,
stable@vger.kernel.org
Subject: [PATCH 5.13] io_uring: Check current->io_uring in io_uring_cancel_sqpoll
Date: Tue, 27 Apr 2021 18:21:49 +0530 [thread overview]
Message-ID: <20210427125148.21816-1-hello@oswalpalash.com> (raw)
In-Reply-To: <e67b2f55-dd0a-1e1f-e34b-87e8613cd701@gmail.com>
syzkaller identified KASAN: null-ptr-deref Write in
io_uring_cancel_sqpoll on v5.12
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.
Reported-by: syzbot+be51ca5a4d97f017cd50@syzkaller.appspotmail.com
Cc: stable@vger.kernel.org
Signed-off-by: Palash Oswal <hello@oswalpalash.com>
---
fs/io_uring.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index dff34975d86b..eccad51b7954 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -8998,6 +8998,8 @@ static void io_uring_cancel_sqpoll(struct io_ring_ctx *ctx)
s64 inflight;
DEFINE_WAIT(wait);
+ if (!current->io_uring)
+ return;
WARN_ON_ONCE(!sqd || ctx->sq_data->thread != current);
atomic_inc(&tctx->in_idle);
--
2.27.0
next prev parent reply other threads:[~2021-04-27 12:52 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-26 9:33 KASAN: null-ptr-deref Write in io_uring_cancel_sqpoll syzbot
[not found] ` <e939af11-7ce8-46af-8c76-651add0ae56bn@googlegroups.com>
2021-04-27 6:29 ` Dmitry Vyukov
2021-04-27 7:05 ` Palash Oswal
2021-04-27 8:37 ` Pavel Begunkov
2021-04-27 10:39 ` Palash Oswal
2021-04-27 11:20 ` Pavel Begunkov
2021-04-27 12:51 ` Palash Oswal [this message]
2021-04-27 13:08 ` [PATCH 5.13] io_uring: Check current->io_uring " Pavel Begunkov
2021-04-27 13:37 ` Jens Axboe
2021-04-27 17:00 ` Pavel Begunkov
2021-04-27 17:00 ` Jens Axboe
2021-04-27 17:04 ` Pavel Begunkov
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