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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> 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> X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 539F6160015 X-Stat-Signature: o358qe3yzcmy9fyyg7yhjb556iuuqi81 X-HE-Tag: 1713222320-556227 X-HE-Meta: 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 6XpCS4bd 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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