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([2600:4040:95d2:7b00:8471:c736:47af:a8b7]) by smtp.gmail.com with ESMTPSA id d75a77b69052e-4b067e71186sm162116021cf.17.2025.08.14.07.50.22 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 14 Aug 2025 07:50:22 -0700 (PDT) Message-ID: Date: Thu, 14 Aug 2025 10:50:21 -0400 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH net-next v6 09/19] net: psp: update the TCP MSS to reflect PSP packet overhead To: Paolo Abeni , Donald Hunter , Jakub Kicinski , "David S. Miller" , Eric Dumazet , Simon Horman , Jonathan Corbet , Andrew Lunn Cc: Saeed Mahameed , Leon Romanovsky , Tariq Toukan , Boris Pismenny , Kuniyuki Iwashima , Willem de Bruijn , David Ahern , Neal Cardwell , Patrisious Haddad , Raed Salem , Jianbo Liu , Dragos Tatulea , Rahul Rameshbabu , Stanislav Fomichev , =?UTF-8?Q?Toke_H=C3=B8iland-J=C3=B8rgensen?= , Alexander Lobakin , Kiran Kella , Jacob Keller , netdev@vger.kernel.org References: <20250812003009.2455540-1-daniel.zahka@gmail.com> <20250812003009.2455540-10-daniel.zahka@gmail.com> Content-Language: en-US From: Daniel Zahka In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 8/14/25 9:58 AM, Paolo Abeni wrote: > On 8/12/25 2:29 AM, Daniel Zahka wrote: >> @@ -236,6 +237,10 @@ int psp_sock_assoc_set_tx(struct sock *sk, struct psp_dev *psd, >> tcp_write_collapse_fence(sk); >> pas->upgrade_seq = tcp_sk(sk)->rcv_nxt; >> >> + icsk = inet_csk(sk); >> + icsk->icsk_ext_hdr_len += psp_sk_overhead(sk); > I'm likely lost, but AFAICS the user-space can successfully call > multiple times psp_sock_assoc_set_tx() on the same socket, increasing > icsk->icsk_ext_hdr_len in an unbounded way. If it were possible to execute the code you have highlighted more than once per socket, that would be a bug. This should not be possible because of the preceding checks in the function i.e.     if (pas->tx.spi) {         NL_SET_ERR_MSG(extack, "Tx key already set");         err = -EBUSY;         goto exit_unlock;     }