diff options
| author | Kirill Tkhai <ktkhai@virtuozzo.com> | 2018-09-25 12:28:55 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-11-21 09:25:57 +0100 |
| commit | 7996b1c0eaefc5745c982301ca483f99555842e4 (patch) | |
| tree | 21313befbce6262d70c6b55c87601f9b82bfc57e /fs/fuse | |
| parent | 0dd45a4df3eb901668cafeefb667bf781a527eb3 (diff) | |
fuse: Fix use-after-free in fuse_dev_do_read()
commit bc78abbd55dd28e2287ec6d6502b842321a17c87 upstream.
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
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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 c94bab6103f5..881d950c3e6a 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -1303,12 +1303,14 @@ 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; |