From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Laight Subject: RE: [PATCH] clone3: validate stack arguments Date: Thu, 31 Oct 2019 11:41:06 +0000 Message-ID: References: <20191031113608.20713-1-christian.brauner@ubuntu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Return-path: In-Reply-To: <20191031113608.20713-1-christian.brauner@ubuntu.com> Content-Language: en-US Sender: stable-owner@vger.kernel.org To: 'Christian Brauner' , "linux-kernel@vger.kernel.org" , Florian Weimer , GNU C Library Cc: Arnd Bergmann , Kees Cook , Jann Horn , David Howells , Ingo Molnar , Oleg Nesterov , Linus Torvalds , Peter Zijlstra , "linux-api@vger.kernel.org" , "stable@vger.kernel.org" List-Id: linux-api@vger.kernel.org From: Christian Brauner > Sent: 31 October 2019 11:36 ... > /* Intentional user visible API change */ > clone3() was released with 5.3. Currently, it is not documented and very > unclear to userspace how the stack and stack_size argument have to be > passed. After talking to glibc folks we concluded that trying to change > clone3() to setup the stack instead of requiring userspace to do this is > the right course of action. What happens if someone 'accidentally' runs a program compiled for the new API on a system running the existing 5.3 kernel? While it won't work, it needs to die reasonably gracefully. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)