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[82.69.66.36]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-475c4378cbesm89230435e9.16.2025.10.23.04.41.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 23 Oct 2025 04:41:29 -0700 (PDT) Date: Thu, 23 Oct 2025 12:40:43 +0100 From: David Laight To: Paolo Abeni Cc: Kees Cook , Jakub Kicinski , "Gustavo A. R. Silva" , Alexei Starovoitov , Daniel Borkmann , John Fastabend , "David S. Miller" , Eric Dumazet , Simon Horman , Kuniyuki Iwashima , Willem de Bruijn , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, bpf@vger.kernel.org, linux-hardening@vger.kernel.org Subject: Re: [PATCH v3 1/9] net: Add struct sockaddr_unspec for sockaddr of unknown length Message-ID: <20251023124043.3dab5646@pumpkin> In-Reply-To: <268ee657-903a-4271-9e17-fcf1dc79b92c@redhat.com> References: <20251020212125.make.115-kees@kernel.org> <20251020212639.1223484-1-kees@kernel.org> <268ee657-903a-4271-9e17-fcf1dc79b92c@redhat.com> X-Mailer: Claws Mail 4.1.1 (GTK 3.24.38; arm-unknown-linux-gnueabihf) Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Thu, 23 Oct 2025 12:43:06 +0200 Paolo Abeni wrote: > On 10/20/25 11:26 PM, Kees Cook wrote: > > Add flexible sockaddr structure to support addresses longer than the > > traditional 14-byte struct sockaddr::sa_data limitation without > > requiring the full 128-byte sa_data of struct sockaddr_storage. This > > allows the network APIs to pass around a pointer to an object that > > isn't lying to the compiler about how big it is, but must be accompanied > > by its actual size as an additional parameter. > > > > It's possible we may way to migrate to including the size with the > > struct in the future, e.g.: > > > > struct sockaddr_unspec { > > u16 sa_data_len; > > u16 sa_family; > > u8 sa_data[] __counted_by(sa_data_len); > > }; > > Side note: sockaddr_unspec is possibly not the optimal name, as > AF_UNSPEC has a specific meaning/semantic. > > Name-wise, I think 'sockaddr_sized' would be better, Or even sockaddr_unsized ? > but I agree with David the struct may cause unaligned access problems. It probably also wants the 'sized_by' attribute rather than 'counted_by'. So wherever the length is saved it is the length the user supplied for the structure (or the sizeof the protocol-specific one). David > > /P > >