From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kees Cook Subject: Re: [PATCH v4 1/4] lib: introduce copy_struct_from_user() helper Date: Thu, 10 Oct 2019 09:43:26 -0700 Message-ID: <201910100943.4C6AB66@keescook> References: <20191001011055.19283-1-cyphar@cyphar.com> <20191001011055.19283-2-cyphar@cyphar.com> <87eezkx2y7.fsf@mpe.ellerman.id.au> <20191010114007.o3bygjf4jlfk242e@yavin.dot.cyphar.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Content-Disposition: inline In-Reply-To: <20191010114007.o3bygjf4jlfk242e@yavin.dot.cyphar.com> To: Aleksa Sarai Cc: Michael Ellerman , Ingo Molnar , Peter Zijlstra , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Christian Brauner , Rasmus Villemoes , Al Viro , Linus Torvalds , libc-alpha@sourceware.org, linux-api@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: linux-api@vger.kernel.org On Thu, Oct 10, 2019 at 10:40:07PM +1100, Aleksa Sarai wrote: > Yeah, it takes about 5-10s on my laptop. We could switch it to just > everything within a 4K block, but the main reason for testing with > 2*PAGE_SIZE is to make sure that check_nonzero_user() works across page > boundaries. Though we could only do check_nonzero_user() in the region > of the page boundary (maybe i E (PAGE_SIZE-512,PAGE_SIZE+512]?) Yeah, I like this idea: just poke at the specific edge-case. -- Kees Cook