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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id w2-20020a62c702000000b0050dc762815fsm1962911pfg.57.2022.05.13.08.44.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 13 May 2022 08:44:37 -0700 (PDT) Date: Fri, 13 May 2022 08:44:33 -0700 From: Kees Cook To: David Howells Cc: "Gustavo A . R . Silva" , Marc Dionne , linux-afs@lists.infradead.org, Alexei Starovoitov , alsa-devel@alsa-project.org, Al Viro , Andrew Gabbasov , Andrew Morton , Andy Gross , Andy Lavr , Arend van Spriel , Baowen Zheng , Bjorn Andersson , Boris Ostrovsky , Bradley Grove , brcm80211-dev-list.pdl@broadcom.com, Christian Brauner , Christian =?iso-8859-1?Q?G=F6ttsche?= , Christian Lamparter , Chris Zankel , Cong Wang , Daniel Axtens , Daniel Vetter , Dan Williams , David Gow , "David S. Miller" , Dennis Dalessandro , devicetree@vger.kernel.org, Dexuan Cui , Dmitry Kasatkin , Eli Cohen , Eric Dumazet , Eric Paris , Eugeniu Rosca , Felipe Balbi , Francis Laniel , Frank Rowand , Franky Lin , Greg Kroah-Hartman , Gregory Greenman , Guenter Roeck , Haiyang Zhang , Hante Meuleman , Herbert Xu , Hulk Robot , Jakub Kicinski , "James E.J. Bottomley" , James Morris , Jarkko Sakkinen , Jaroslav Kysela , Jason Gunthorpe , Jens Axboe , Johan Hedberg , Johannes Berg , Johannes Berg , John Keeping , Juergen Gross , Kalle Valo , Keith Packard , keyrings@vger.kernel.org, kunit-dev@googlegroups.com, Kuniyuki Iwashima , "K. Y. Srinivasan" , Lars-Peter Clausen , Lee Jones , Leon Romanovsky , Liam Girdwood , linux1394-devel@lists.sourceforge.net, linux-arm-kernel@lists.infradead.org, linux-arm-msm@vger.kernel.org, linux-bluetooth@vger.kernel.org, linux-hardening@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-integrity@vger.kernel.org, linux-rdma@vger.kernel.org, linux-scsi@vger.kernel.org, linux-security-module@vger.kernel.org, linux-usb@vger.kernel.org, linux-wireless@vger.kernel.org, linux-xtensa@linux-xtensa.org, llvm@lists.linux.dev, Loic Poulain , Louis Peens , Luca Coelho , Luiz Augusto von Dentz , Marcel Holtmann , Mark Brown , "Martin K. Petersen" , Max Filippov , Mimi Zohar , Muchun Song , Nathan Chancellor , netdev@vger.kernel.org, Nick Desaulniers , Nuno =?iso-8859-1?Q?S=E1?= , Paolo Abeni , Paul Moore , Rich Felker , Rob Herring , Russell King , selinux@vger.kernel.org, "Serge E. Hallyn" , SHA-cyfmac-dev-list@infineon.com, Simon Horman , Stefano Stabellini , Stefan Richter , Steffen Klassert , Stephen Hemminger , Stephen Smalley , Tadeusz Struk , Takashi Iwai , Tom Rix , Udipto Goswami , Vincenzo Frascino , wcn36xx@lists.infradead.org, Wei Liu , xen-devel@lists.xenproject.org, Xiu Jianfeng , Yang Yingliang Subject: Re: [PATCH 19/32] afs: Use mem_to_flex_dup() with struct afs_acl Message-ID: <202205130841.686F21B64@keescook> References: <20220504014440.3697851-20-keescook@chromium.org> <20220504014440.3697851-1-keescook@chromium.org> <898803.1652391665@warthog.procyon.org.uk> Precedence: bulk X-Mailing-List: llvm@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: <898803.1652391665@warthog.procyon.org.uk> On Thu, May 12, 2022 at 10:41:05PM +0100, David Howells wrote: > > Kees Cook wrote: > > > struct afs_acl { > > - u32 size; > > - u8 data[]; > > + DECLARE_FLEX_ARRAY_ELEMENTS_COUNT(u32, size); > > + DECLARE_FLEX_ARRAY_ELEMENTS(u8, data); > > }; > > Oof... That's really quite unpleasant syntax. Is it not possible to have > mem_to_flex_dup() and friends work without that? You are telling them the > fields they have to fill in. Other threads discussed this too. I'm hoping to have something more flexible (pardon the pun) in v2. > [...] > or: > > ret = mem_to_flex_dup(&acl, buffer, size, GFP_KERNEL); > if (ret < 0) > > (or use != 0 rather than < 0) Sure, I can make the tests more explicit. The kerndoc, etc all shows it's using < 0 for errors. -- Kees Cook