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[73.241.150.58]) by smtp.gmail.com with ESMTPSA id a8sm1403723pga.64.2020.06.18.21.42.16 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 18 Jun 2020 21:42:18 -0700 (PDT) Subject: Re: [PATCH net] net: increment xmit_recursion level in dev_direct_xmit() To: David Miller , edumazet@google.com Cc: netdev@vger.kernel.org, eric.dumazet@gmail.com, kuba@kernel.org, syzkaller@googlegroups.com References: <20200618052325.78441-1-edumazet@google.com> <20200618.204830.1094276610079682944.davem@davemloft.net> From: Eric Dumazet Message-ID: <363832b8-1d7e-1e9e-8887-ef97d748b0c7@gmail.com> Date: Thu, 18 Jun 2020 21:42:16 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.8.1 MIME-Version: 1.0 In-Reply-To: <20200618.204830.1094276610079682944.davem@davemloft.net> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 6/18/20 8:48 PM, David Miller wrote: > From: Eric Dumazet > Date: Wed, 17 Jun 2020 22:23:25 -0700 > >> Back in commit f60e5990d9c1 ("ipv6: protect skb->sk accesses >> from recursive dereference inside the stack") Hannes added code >> so that IPv6 stack would not trust skb->sk for typical cases >> where packet goes through 'standard' xmit path (__dev_queue_xmit()) >> >> Alas af_packet had a dev_direct_xmit() path that was not >> dealing yet with xmit_recursion level. >> >> Also change sk_mc_loop() to dump a stack once only. >> >> Without this patch, syzbot was able to trigger : > ... >> f60e5990d9c1 ("ipv6: protect skb->sk accesses from recursive dereference inside the stack") >> Signed-off-by: Eric Dumazet >> Reported-by: syzbot > > Applied and queued up for -stable. > > I only noticed after pushing this out the missing "Fixes: " prefix, but not > much I can do about this now sorry :-/ Oh right, sorry for this.