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From:   Kalle Valo <kvalo@kernel.org>
To:     <Ajay.Kathat@microchip.com>
Cc:     <zhangxiaoxu5@huawei.com>, <linux-wireless@vger.kernel.org>,
        <netdev@vger.kernel.org>, <davem@davemloft.net>,
        <edumazet@google.com>, <kuba@kernel.org>, <pabeni@redhat.com>,
        <Claudiu.Beznea@microchip.com>
Subject: Re: [PATCH wireless] wifi: wilc1000: Fix UAF in wilc_netdev_cleanup() when iterator the RCU list
References: <20221124151349.2386077-1-zhangxiaoxu5@huawei.com>
        <a6d8f548-bcf4-4a02-df25-3a06aa8f2b42@microchip.com>
Date:   Fri, 25 Nov 2022 18:42:05 +0200
In-Reply-To: <a6d8f548-bcf4-4a02-df25-3a06aa8f2b42@microchip.com> (Ajay
        Kathat's message of "Fri, 25 Nov 2022 16:17:16 +0000")
Message-ID: <877czj6l5u.fsf@kernel.org>
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<Ajay.Kathat@microchip.com> writes:

> On 24/11/22 20:43, Zhang Xiaoxu wrote:
>
>  EXTERNAL EMAIL: Do not click links or open attachments unless you know the
>  content is safe
>
> There is a UAF read when remove the wilc1000_spi module:
>
>  BUG: KASAN: use-after-free in wilc_netdev_cleanup.cold+0xc4/0xe0 [wilc1000]
>  Read of size 8 at addr ffff888116846900 by task rmmod/386
>
>  CPU: 2 PID: 386 Comm: rmmod Tainted: G                 N 6.1.0-rc6+ #8
>  Call Trace:
>   dump_stack_lvl+0x68/0x85
>   print_report+0x16c/0x4a3
>   kasan_report+0x95/0x190
>   wilc_netdev_cleanup.cold+0xc4/0xe0
>   wilc_bus_remove+0x52/0x60
>   spi_remove+0x46/0x60
>   device_remove+0x73/0xc0
>   device_release_driver_internal+0x12d/0x210
>   driver_detach+0x84/0x100
>   bus_remove_driver+0x90/0x120
>   driver_unregister+0x4f/0x80
>   __x64_sys_delete_module+0x2fc/0x440
>   do_syscall_64+0x38/0x90
>   entry_SYSCALL_64_after_hwframe+0x63/0xcd
>
> Since set 'needs_free_netdev=true' when initialize the net device, the
> net device will be freed when unregister, then use the freed 'vif' to
> find the next will UAF read.
>
> Did you test this behaviour on the real device. I am seeing a kernel
> crash when the module is unloaded after the connection with an AP. As
> I see, "vif_list" is used to maintain the interface list, so even when
> one interface is removed, another element is fetched from the
> "vif_list", not using the freed "vif"

Ajay, please don't use HTML as our lists drop those.

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