Re: Use-after-free in Linux tc subsystem (v6.15)

[Victor Nogueira <victor@mojatatu.com>]

On 6/30/25 08:06, Jamal Hadi Salim wrote:
> On Sun, Jun 29, 2025 at 5:08 PM Cong Wang <xiyou.wangcong@gmail.com> wrote:
>>
>> On Sat, Jun 28, 2025 at 05:26:59PM -0400, Jamal Hadi Salim wrote:
>>> On Thu, Jun 26, 2025 at 1:11 AM Mingi Cho <mgcho.minic@gmail.com> wrote:
>>>> Hello,
>>>>
>>>> I think the testcase I reported earlier actually contains two
>>>> different bugs. The first is returning SUCCESS with an empty TBF qdisc
>>>> in tbf_segment, and the second is returning SUCCESS with an empty QFQ
>>>> qdisc in qfq_enqueue.
>>>>
>>>
>>> Please join the list where a more general solution is being discussed here:
>>> https://lore.kernel.org/netdev/aF847kk6H+kr5kIV@pop-os.localdomain/
>>
>> I think that one is different, the one here is related to GSO, the above
>> linked one is not. Let me think about the GSO issue, since I already
>> looked into it before.
> 
> TBH, they all look the same to me - at minimal, they should be tested
> against Lion's patch first. Maybe there's a GSO corner case but wasnt
> clear to me.

I did a quick test of Lion's patch using Mingi's C reproducer.
The patch seems to fix the UAF.

cheers,
Victor