From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 93AA7188CB1; Tue, 10 Sep 2024 14:29:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725978586; cv=none; b=ttfCk+324ejDsJ6e7zsJvp0QldgOjGVoVM9iwQ4A3NpnPKD9Fv9nYl2dwX+xLo3i80x9Yprz6uQr4kKjK0smXjML+4XTl5bAox2sF/j2SQv+UPp7sFGFanePLCvbRTUAA0n2tJT8cQ3ov+RAgHA1woh+PyGd595rIKBg2ao46m8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725978586; c=relaxed/simple; bh=vY1Jz/iNW8rD4ftl82lDwp8W3DQ6526OfIQWJPSpGhM=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=CWj0ETYBHFQ90SZl+3uWm+3McxldN8zV5rN0PnWljZDFEwymzY3mujAocNKHPtoi86gTf8MCpI2Y5FVBvicBJPdd41DX9VcgcraB8U6S8zRWtS74pW6810vj2EXiRvRVPPPJDDjQX4l+mndpRL3tYRnh0LDiB0Ngc0wl9bSE94Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=du7ZEAq9; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="du7ZEAq9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AA0FFC4CECE; Tue, 10 Sep 2024 14:29:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1725978586; bh=vY1Jz/iNW8rD4ftl82lDwp8W3DQ6526OfIQWJPSpGhM=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=du7ZEAq9BgDS2Wir7l0S6HhcUJLddeeEQk2ADx3BGjCR8IUN1yz8eat3aGNNHI5mE kS5Mbse1YYCBOx1ImXqp5s9bmY5sAHKjppFXMNDLSimIKfYJm7Ny9Vmo9Itzkbt3Hd N5SbUCZBTl1sNm437nM3ZoYr3olYJVAwB+oT72LBqcJkjhU0QEBdoreEI0UrAJFOwV dT/UfHcWp/fRMNeq7xblSQXEB067HXgZuSB9d0cRYPD0CzNUhscLRTnfmgJt4c1YGM LwyRxe13TOvB4w/YycKc1ZxVqc29xXFeMliLgUACH+GxK2PWQNiMOxplmfG2Tqf04T JdOpQdGzIEZPA== Message-ID: <8ad4406e-cdd3-4204-928e-6ac6dd628cbc@kernel.org> Date: Tue, 10 Sep 2024 16:29:38 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Beta Subject: Re: [PATCH net V4] mptcp: pm: Fix uaf in __timer_delete_sync Content-Language: en-GB To: Edward Adam Davis Cc: davem@davemloft.net, edumazet@google.com, geliang@kernel.org, kuba@kernel.org, linux-kernel@vger.kernel.org, martineau@kernel.org, mptcp@lists.linux.dev, netdev@vger.kernel.org, pabeni@redhat.com, syzbot+f3a31fb909db9b2a5c4d@syzkaller.appspotmail.com, syzkaller-bugs@googlegroups.com References: From: Matthieu Baerts Autocrypt: addr=matttbe@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit Hi Edward, On 10/09/2024 11:58, Edward Adam Davis wrote: > There are two paths to access mptcp_pm_del_add_timer, result in a race > condition: > > CPU1 CPU2 > ==== ==== > net_rx_action > napi_poll netlink_sendmsg > __napi_poll netlink_unicast > process_backlog netlink_unicast_kernel > __netif_receive_skb genl_rcv > __netif_receive_skb_one_core netlink_rcv_skb > NF_HOOK genl_rcv_msg > ip_local_deliver_finish genl_family_rcv_msg > ip_protocol_deliver_rcu genl_family_rcv_msg_doit > tcp_v4_rcv mptcp_pm_nl_flush_addrs_doit > tcp_v4_do_rcv mptcp_nl_remove_addrs_list > tcp_rcv_established mptcp_pm_remove_addrs_and_subflows > tcp_data_queue remove_anno_list_by_saddr > mptcp_incoming_options mptcp_pm_del_add_timer > mptcp_pm_del_add_timer kfree(entry) > > In remove_anno_list_by_saddr(running on CPU2), after leaving the critical > zone protected by "pm.lock", the entry will be released, which leads to the > occurrence of uaf in the mptcp_pm_del_add_timer(running on CPU1). > > Keeping a reference to add_timer inside the lock, and calling > sk_stop_timer_sync() with this reference, instead of "entry->add_timer". > > Move list_del(&entry->list) to mptcp_pm_del_add_timer and inside the pm lock, > do not directly access any members of the entry outside the pm lock, which > can avoid similar "entry->x" uaf. > > Fixes: 00cfd77b9063 ("mptcp: retransmit ADD_ADDR when timeout") > Cc: stable@vger.kernel.org > Reported-and-tested-by: syzbot+f3a31fb909db9b2a5c4d@syzkaller.appspotmail.com > Closes: https://syzkaller.appspot.com/bug?extid=f3a31fb909db9b2a5c4d > Signed-off-by: Matthieu Baerts (NGI0) > Signed-off-by: Edward Adam Davis It looks also good to me, but no need for me to add a reviewed-by tag I suppose. This v4 can be applied in netdev directly. Cheers, Matt -- Sponsored by the NGI0 Core fund.