From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ed1-f53.google.com (mail-ed1-f53.google.com [209.85.208.53]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 51AFF202C43; Tue, 1 Apr 2025 12:17:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.208.53 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743509840; cv=none; b=hmw15woHNDBTkA2D+fddOw0IOdQPKrsKN5dBAj/+C7PCtdAvblJLrI78PRv2gRL/LBfIgzgHzQdx814p1B07zPcXUZF0zrBetl7bCS2sXtZPO/ET3UuZWG6cTpkXB2Ah1dnewVltEdJGuo8lrACzRTxGs0QM7a9JU6k5S8no4tI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743509840; c=relaxed/simple; bh=3mz+zkd+0flPsLy0Ofm1nfq5/fbalcBJT6YtqE7p5ow=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=I8zeAEvoysEcIgNohRvdpRKXCNIOGs/ALc1FcAiwmMyEHnzs4WYD7LP16kJwEE2hHWhIWK5wZccMbXRvR063MsQ3cFIWaTIJJCBGxtaIkBhGAm2n9X6YUKNIS/qIXHNAmAFlQkJvcBa224zj37Sam10Oc4Bz2xsPQRPxRfwEHeA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=debian.org; spf=pass smtp.mailfrom=gmail.com; arc=none smtp.client-ip=209.85.208.53 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=debian.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Received: by mail-ed1-f53.google.com with SMTP id 4fb4d7f45d1cf-5e61d91a087so8869557a12.0; Tue, 01 Apr 2025 05:17:17 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1743509836; x=1744114636; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=Le/fZ22YF+TB0PY0qqmz1Qiiab5GI/mdQmTFzYxcG4I=; b=lGS8cPakR10lPsQP32dBYfw6VCRHwEUppLMrUGjGeuVUFBHhQ2hcxZvrxwjc4dpdxH EH282upxF8vxrWG8a8Y+NnHgSiHeR7/2nF1DUbhqkANtmramr71TbDjX1sbMjDyPosDO /Al/Py/MMpgp/CK2xVVIy8nvGlYGaGoSjdtfwcqovBotuv46ApZag9TU5AsukAExGVMI x1XWc47Ac4WsHrLY/BTFRpilQ5lbFdA/+TPXL4VKyCNlQyf2rHSXQU/l3ZIJ1vWQTEIy 3WDRmJTG7S0XdpWK2nuuWFhNjIy83f2FVviZZ/QPZuvgETkNivofk0ocZRteX60HxI5y DuMA== X-Forwarded-Encrypted: i=1; AJvYcCUJimNA5ofSI6Br4oJeya4nW4JsFP+U4aLDZn7zvvnNIr1e2VeZg27/JP+7LmCdhCQFHq0YrA==@lists.linux.dev, AJvYcCXDBqzVv4wFxz8sJKrkz4en+LmGRuCI2IfOOm+Ik8kfv9CCmvYi6H/qTOzNquY7c+/aK3/0HoOzjI1jTswSzF8=@lists.linux.dev X-Gm-Message-State: AOJu0YwOVCCSWLk0yL+s506vVf+t3KAi8kpQdgzCq36gX63U5+l9zmem gm1iQ2JgYCtngG6VhQFnBiaWs5CL1yVTyMloVKjp+j7YbeRF6pn1 X-Gm-Gg: ASbGncs+vl3zxkVrxq5mIk5swwNunPuYTr775Yq02FZVjeT2BSCKHQ2emskKLC5eq0D brBaVaO3hadPMZWKhlJdr0bpVMWvITpTZpYnkdZRs8sEpTNsZ2uD82lFfdPX9vL76Ww7AtDmQpI rLFyGHJLyJJPAoyPDEzTrKSjJzPnCnTPdAkTGKeMCG6kCGbohg21euivmonC/y6T8CHd7sykwZP TbrfzZiK3mp2zc94p0TWXzlTCjKPwRa9vDrSSe6ha+DZ67powYKEw4zoNCfjha6rarz3phtxFVl 83xGfhlHHy+hhe1yZiaF8Dx3P0fsDBrPbZM= X-Google-Smtp-Source: AGHT+IFIWumNmX/1ZXWS3yLA6haOkNuwqHqavN++vEeVvWZeAOABaH1HwDwax0vsW9FqMkDo2Sxlag== X-Received: by 2002:a05:6402:26c8:b0:5e5:be7f:a1f6 with SMTP id 4fb4d7f45d1cf-5edfcc021a5mr10721198a12.1.1743509836211; Tue, 01 Apr 2025 05:17:16 -0700 (PDT) Received: from gmail.com ([2a03:2880:30ff:3::]) by smtp.gmail.com with ESMTPSA id 4fb4d7f45d1cf-5edc16eda94sm7144316a12.33.2025.04.01.05.17.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 01 Apr 2025 05:17:14 -0700 (PDT) Date: Tue, 1 Apr 2025 05:17:09 -0700 From: Breno Leitao To: Stefan Metzmacher Cc: Linus Torvalds , Jens Axboe , Pavel Begunkov , Jakub Kicinski , Christoph Hellwig , Karsten Keil , Ayush Sawal , Andrew Lunn , "David S. Miller" , Eric Dumazet , Paolo Abeni , Simon Horman , Kuniyuki Iwashima , Willem de Bruijn , David Ahern , Marcelo Ricardo Leitner , Xin Long , Neal Cardwell , Joerg Reuter , Marcel Holtmann , Johan Hedberg , Luiz Augusto von Dentz , Oliver Hartkopp , Marc Kleine-Budde , Robin van der Gracht , Oleksij Rempel , kernel@pengutronix.de, Alexander Aring , Stefan Schmidt , Miquel Raynal , Alexandra Winter , Thorsten Winkler , James Chapman , Jeremy Kerr , Matt Johnston , Matthieu Baerts , Mat Martineau , Geliang Tang , Krzysztof Kozlowski , Remi Denis-Courmont , Allison Henderson , David Howells , Marc Dionne , Wenjia Zhang , Jan Karcher , "D. Wythe" , Tony Lu , Wen Gu , Jon Maloy , Boris Pismenny , John Fastabend , Stefano Garzarella , Martin Schiller , =?iso-8859-1?Q?Bj=F6rn_T=F6pel?= , Magnus Karlsson , Maciej Fijalkowski , Jonathan Lemon , Alexei Starovoitov , Daniel Borkmann , Jesper Dangaard Brouer , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-sctp@vger.kernel.org, linux-hams@vger.kernel.org, linux-bluetooth@vger.kernel.org, linux-can@vger.kernel.org, dccp@vger.kernel.org, linux-wpan@vger.kernel.org, linux-s390@vger.kernel.org, mptcp@lists.linux.dev, linux-rdma@vger.kernel.org, rds-devel@oss.oracle.com, linux-afs@lists.infradead.org, tipc-discussion@lists.sourceforge.net, virtualization@lists.linux.dev, linux-x25@vger.kernel.org, bpf@vger.kernel.org, isdn4linux@listserv.isdn4linux.de, io-uring@vger.kernel.org Subject: Re: [RFC PATCH 1/4] net: introduce get_optlen() and put_optlen() helpers Message-ID: References: <156e83128747b2cf7c755bffa68f2519bd255f78.1743449872.git.metze@samba.org> Precedence: bulk X-Mailing-List: virtualization@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <156e83128747b2cf7c755bffa68f2519bd255f78.1743449872.git.metze@samba.org> Hello Stefan, On Mon, Mar 31, 2025 at 10:10:53PM +0200, Stefan Metzmacher wrote: > --- a/include/linux/sockptr.h > +++ b/include/linux/sockptr.h > @@ -169,4 +169,26 @@ static inline int check_zeroed_sockptr(sockptr_t src, size_t offset, > return memchr_inv(src.kernel + offset, 0, size) == NULL; > } > > +#define __check_optlen_t(__optlen) \ > +({ \ > + int __user *__ptr __maybe_unused = __optlen; \ > + BUILD_BUG_ON(sizeof(*(__ptr)) != sizeof(int)); \ > +}) I am a bit confused about this macro. I understand that this macro's goal is to check that __optlen is a pointer to an integer, otherwise failed to build. It is unclear to me if that is what it does. Let's suppose that __optlen is not an integer pointer. Then: > int __user *__ptr __maybe_unused = __optlen; This will generate a compile failure/warning due invalid casting, depending on -Wincompatible-pointer-types. > BUILD_BUG_ON(sizeof(*(__ptr)) != sizeof(int)); Then this comparison will always false, since __ptr is a pointer to int, and you are comparing the size of its content with the sizeof(int).