linux-kernel - Re: [PATCH] io_uring: fix memory leak of UNIX domain socket inode

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Message-ID: <c8afa475-8ed9-e8ee-c66a-270bea7efad5@kernel.dk>
Date:   Thu, 13 Jun 2019 02:40:13 -0600
From:   Jens Axboe <axboe@...nel.dk>
To:     Eric Biggers <ebiggers@...nel.org>,
        Alexander Viro <viro@...iv.linux.org.uk>,
        linux-block@...r.kernel.org, linux-fsdevel@...r.kernel.org
Cc:     davem@...emloft.net, linux-kernel@...r.kernel.org,
        netdev@...r.kernel.org, syzkaller-bugs@...glegroups.com,
        syzbot <syzbot+111cb28d9f583693aefa@...kaller.appspotmail.com>
Subject: Re: [PATCH] io_uring: fix memory leak of UNIX domain socket inode

On 6/12/19 3:58 PM, Eric Biggers wrote:
> From: Eric Biggers <ebiggers@...gle.com>
> 
> Opening and closing an io_uring instance leaks a UNIX domain socket
> inode.  This is because the ->file of the io_uring instance's internal
> UNIX domain socket is set to point to the io_uring file, but then
> sock_release() sees the non-NULL ->file and assumes the inode reference
> is held by the file so doesn't call iput().  That's not the case here,
> since the reference is still meant to be held by the socket; the actual
> inode of the io_uring file is different.
> 
> Fix this leak by NULL-ing out ->file before releasing the socket.

Thanks, applied.

-- 
Jens Axboe