Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Sat, 18 Apr 2020 13:18:30 -0700 (PDT)
Message-Id: <20200418.131830.1251168077969815139.davem@davemloft.net>
To:     xiyuyang19@fudan.edu.cn
Cc:     jmaloy@redhat.com, ying.xue@windriver.com, kuba@kernel.org,
        netdev@vger.kernel.org, tipc-discussion@lists.sourceforge.net,
        linux-kernel@vger.kernel.org, yuanxzhang@fudan.edu.cn,
        kjlu@umn.edu, tanxin.ctf@gmail.com
Subject: Re: [PATCH] tipc: Fix potential tipc_aead refcnt leak in
 tipc_crypto_rcv
From:   David Miller <davem@davemloft.net>
In-Reply-To: <1586939996-69937-1-git-send-email-xiyuyang19@fudan.edu.cn>
References: <1586939996-69937-1-git-send-email-xiyuyang19@fudan.edu.cn>
Mime-Version: 1.0
Content-Type: Text/Plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

From: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Date: Wed, 15 Apr 2020 16:39:56 +0800

> tipc_crypto_rcv() invokes tipc_aead_get(), which returns a reference of
> the tipc_aead object to "aead" with increased refcnt.
> 
> When tipc_crypto_rcv() returns, the original local reference of "aead"
> becomes invalid, so the refcount should be decreased to keep refcount
> balanced.
> 
> The issue happens in one error path of tipc_crypto_rcv(). When TIPC
> message decryption status is EINPROGRESS or EBUSY, the function forgets
> to decrease the refcnt increased by tipc_aead_get() and causes a refcnt
> leak.
> 
> Fix this issue by calling tipc_aead_put() on the error path when TIPC
> message decryption status is EINPROGRESS or EBUSY.
> 
> Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
> Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>

Applied and queued up for -stable.

This code is harder to audit than it needs to be due to the special
casing of things like -ENOKEY etc.  It should rather explicitly handle
the NULL test on aead in this top-level piece of code, which would
make the validation of aead reference counting much more explicit and
clear.