From: Kirill Tkhai <ktkhai@virtuozzo.com>
To: miklos@szeredi.hu,
syzbot+4e975615ca01f2277bdd@syzkaller.appspotmail.com,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
ktkhai@virtuozzo.com
Subject: [PATCH] fuse: Fix use-after-free in fuse_dev_do_read()
Date: Tue, 25 Sep 2018 12:28:55 +0300 [thread overview]
Message-ID: <153786771676.20496.9149001582398031266.stgit@localhost.localdomain> (raw)
We may pick freed req in this way:
[cpu0] [cpu1]
fuse_dev_do_read() fuse_dev_do_write()
list_move_tail(&req->list, &fpq->processing); ...
spin_unlock(&fpq->lock); ...
... request_end(fc, req);
... fuse_put_request(fc, req);
if (test_bit(FR_INTERRUPTED, &req->flags))
queue_interrupt(fiq, req);
Fix that by keeping req alive till we finish all manipulations.
Reported-by: syzbot+4e975615ca01f2277bdd@syzkaller.appspotmail.com
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
---
fs/fuse/dev.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index 11ea2c4a38ab..675caed3e655 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -1311,12 +1311,14 @@ static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file,
goto out_end;
}
list_move_tail(&req->list, &fpq->processing);
+ __fuse_get_request(req);
spin_unlock(&fpq->lock);
set_bit(FR_SENT, &req->flags);
/* matches barrier in request_wait_answer() */
smp_mb__after_atomic();
if (test_bit(FR_INTERRUPTED, &req->flags))
queue_interrupt(fiq, req);
+ fuse_put_request(fc, req);
return reqsize;
next reply other threads:[~2018-09-25 9:29 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-25 9:28 Kirill Tkhai [this message]
2018-10-01 9:25 ` [PATCH] fuse: Fix use-after-free in fuse_dev_do_read() Miklos Szeredi
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