netdev - Re: [BUG net] possible use after free bugs due to race condition

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Message-ID: <20240812190057.GB21559@breakpoint.cc>
Date: Mon, 12 Aug 2024 21:00:57 +0200
From: Florian Westphal <fw@...len.de>
To: wkx <13514081436@....com>
Cc: davem@...emloft.net, edumazet@...gle.com, kuba@...nel.org,
	pabeni@...hat.com, netdev@...r.kernel.org,
	21210240012@...udan.edu.cn
Subject: Re: [BUG net] possible use after free bugs due to race condition

wkx <13514081436@....com> wrote:
> 
> 
> Our team recently developed a vulnerability detection tool, and we have employed it to scan the Linux Kernel (version 6.9.6). After manual review, we found some potentially vulnerable code snippets, which may have use-after-free bugs due to race conditions. Therefore, we would appreciate your expert insight to confirm whether these vulnerabilities could indeed pose a risk to the system.
> 
> 1. /drivers/net/ethernet/broadcom/bcm63xx_enet.c
> 
> In bcm_enet_probe, &priv->mib_update_task is bounded with bcm_enet_update_mib_counters_defer. bcm_enet_isr_mac will be called to start the work.
> If we remove the driver which will call bcm_enet_remove to make a cleanup, there may be unfinished work.
> The possible sequence is as follows:
> CPU0                                             CPU1
>  
>                                       | bcm_enet_update_mib_counters_defer
> bcm_enet_remove        |

  unregister_netdev(dev);

... which should end up calling bcm_enet_stop() (via ops->ndo_stop in
__dev_close_many()).  This calls cancel_work_sync().

Did not look at the others.