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| author | Kirill Tkhai <ktkhai@virtuozzo.com> | 2018-09-25 11:28:55 +0200 |
|---|---|---|
| committer | Miklos Szeredi <mszeredi@redhat.com> | 2018-09-28 16:43:21 +0200 |
| commit | bc78abbd55dd28e2287ec6d6502b842321a17c87 (patch) | |
| tree | 855aa7c8235688bb2ba0eed8ea56d942bea1c674 /fs/fuse | |
| parent | Linux 4.19-rc5 (diff) | |
| download | linux-bc78abbd55dd28e2287ec6d6502b842321a17c87.tar.xz linux-bc78abbd55dd28e2287ec6d6502b842321a17c87.zip | |
fuse: Fix use-after-free in fuse_dev_do_read()
We may pick freed req in this way:
[cpu0] [cpu1]
fuse_dev_do_read() fuse_dev_do_write()
list_move_tail(&req->list, ...); ...
spin_unlock(&fpq->lock); ...
... request_end(fc, req);
... fuse_put_request(fc, req);
if (test_bit(FR_INTERRUPTED, ...))
queue_interrupt(fiq, req);
Fix that by keeping req alive until we finish all manipulations.
Reported-by: syzbot+4e975615ca01f2277bdd@syzkaller.appspotmail.com
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Fixes: 46c34a348b0a ("fuse: no fc->lock for pqueue parts")
Cc: <stable@vger.kernel.org> # v4.2
Diffstat (limited to 'fs/fuse')
| -rw-r--r-- | fs/fuse/dev.c | 2 |
1 files changed, 2 insertions, 0 deletions
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; |