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Mon, 15 Apr 2024 16:05:19 -0700 (PDT) Received: from www.outflux.net ([198.0.35.241]) by smtp.gmail.com with ESMTPSA id go26-20020a056a003b1a00b006edceb4ea9dsm7679876pfb.166.2024.04.15.16.05.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 15 Apr 2024 16:05:18 -0700 (PDT) Date: Mon, 15 Apr 2024 16:05:17 -0700 From: Kees Cook To: Alice Ryhl Cc: Miguel Ojeda , Matthew Wilcox , Al Viro , Andrew Morton , Alex Gaynor , Wedson Almeida Filho , Boqun Feng , Gary Guo , =?iso-8859-1?Q?Bj=F6rn?= Roy Baron , Benno Lossin , Andreas Hindborg , Greg Kroah-Hartman , Arve =?iso-8859-1?B?SGr4bm5lduVn?= , Todd Kjos , Martijn Coenen , Joel Fernandes , Carlos Llamas , Suren Baghdasaryan , Arnd Bergmann , linux-mm@kvack.org, linux-kernel@vger.kernel.org, rust-for-linux@vger.kernel.org, Christian Brauner Subject: Re: [PATCH v5 2/4] uaccess: always export _copy_[from|to]_user with CONFIG_RUST Message-ID: <202404151605.6EFC791E@keescook> References: <20240415-alice-mm-v5-0-6f55e4d8ef51@google.com> <20240415-alice-mm-v5-2-6f55e4d8ef51@google.com> Precedence: bulk X-Mailing-List: rust-for-linux@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240415-alice-mm-v5-2-6f55e4d8ef51@google.com> On Mon, Apr 15, 2024 at 07:13:54AM +0000, Alice Ryhl wrote: > From: Arnd Bergmann > > Rust code needs to be able to access _copy_from_user and _copy_to_user > so that it can skip the check_copy_size check in cases where the length > is known at compile-time, mirroring the logic for when C code will skip > check_copy_size. To do this, we ensure that exported versions of these > methods are available when CONFIG_RUST is enabled. > > Alice has verified that this patch passes the CONFIG_TEST_USER_COPY test > on x86 using the Android cuttlefish emulator. > > Signed-off-by: Arnd Bergmann Thanks for the updates and the comment on testing. :) Reviewed-by: Kees Cook -- Kees Cook