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Thu, 14 May 2026 19:34:28 -0700 (PDT) Date: Fri, 15 May 2026 11:34:23 +0900 From: Hyunwoo Kim To: Jiayuan Chen Cc: Sultan Alsawaf , davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, horms@kernel.org, kerneljasonxing@gmail.com, kuniyu@google.com, mhal@rbox.co, steffen.klassert@secunet.com, vakzz@zellic.io, ben@decadent.org.uk, herbert@gondor.apana.org.au, dsahern@kernel.org, netdev@vger.kernel.org, stable@vger.kernel.org, imv4bel@gmail.com Subject: Re: [PATCH net v2] net: skbuff: propagate shared-frag marker through frag-transfer helpers Message-ID: References: Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Fri, May 15, 2026 at 10:01:50AM +0800, Jiayuan Chen wrote: > > On 5/14/26 5:23 PM, Hyunwoo Kim wrote: > > On Wed, May 13, 2026 at 11:18:10PM -0700, Sultan Alsawaf wrote: > > > On Thu, May 14, 2026 at 06:07:44AM +0900, Hyunwoo Kim wrote: > > > > Changes in v2: > > > > - Also propagate SHARED_FRAG in skb_shift() > > > > - v1: https://lore.kernel.org/all/agRfuVOeMI5pbHhY@v4bel/ > > > Hi Hyunwoo, > > > > > > I've been working on mitigating this vulnerability as a member of the kernel > > > team at CIQ, a distro vendor. In particular, we wanted to make sure that there > > > weren't any lingering places missing SHARED_FRAG propagation. > > > > > > To that end, I used Claude to discover that skb_gro_receive() remained unpatched > > > (as you pointed out in the v1 thread). And then I generated a PoC exploiting the > > > vulnerable skb_gro_receive() path. > > > > > > The PoC is a modified version of the original fragnesia PoC. It works 100% of > > > the time, just like the original fragnesia PoC. > > > > > > I have attached the PoC and a patch that fixes skb_gro_receive(). Please take a > > > look at them. > > > > > > Thanks, > > > Sultan > > Nice catch. Thank you. > > > > After testing, I plan to merge your patch with v2 into a single patch (not a > > series) and submit it as v3. I would appreciate it if you could then add an > > appropriate credit tag of your own. > > When sending v3, remember to rebase net tree first then generate the patch. > > https://web.git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git/commit/?id=f84eca5817390257cef78013d0112481c503b4a3 Thanks for the heads-up. I'll send v4 shortly. See also: https://lore.kernel.org/all/agZEC3YDCAhkrcvr@v4bel/ Will rebase onto netdev before sending. Best regards, Hyunwoo Kim > > > Thanks > > > Also, I would appreciate it if you could use AI to explore additional > > propagation variant paths. From my own analysis, no further ones have been > > identified. > > > > > > Best regards, > > Hyunwoo Kim > > > > > >