From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Hansen Subject: Re: [RFC PATCH v9 01/27] Documentation/x86: Add CET description Date: Mon, 9 Mar 2020 13:59:52 -0700 Message-ID: <0088001c-0b12-a7dc-ff2a-9d5c282fa36b@intel.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: "H.J. Lu" , Andy Lutomirski Cc: Yu-cheng Yu , the arch/x86 maintainers , "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , LKML , linux-doc@vger.kernel.org, Linux-MM , linux-arch , Linux API , Arnd Bergmann , Andy Lutomirski , Balbir Singh , Borislav Petkov , Cyrill Gorcunov , Dave Hansen , Eugene Syromiatnikov , Florian Weimer , Jann Horn , Jonathan Corbet , Kees Cook List-Id: linux-arch.vger.kernel.org On 3/9/20 1:54 PM, H.J. Lu wrote: >> If a program with the magic ELF CET flags missing can’t make a >> thread with IBT and/or SHSTK enabled, then I think we’ve made an >> error and should fix it. >> > A non-CET program can start a CET program and vice versa. Could we be specific here, please? HJ are you saying that: * CET program can execve() a non-CET program, and * a non-CET program can execve() a CET program ? That's obvious. But what are the rules for clone()? Should there be rules for mismatches for CET enabling between threads if a process (not child processes)? From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Subject: Re: [RFC PATCH v9 01/27] Documentation/x86: Add CET description References: From: Dave Hansen Message-ID: <0088001c-0b12-a7dc-ff2a-9d5c282fa36b@intel.com> Date: Mon, 9 Mar 2020 13:59:52 -0700 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-doc-owner@vger.kernel.org To: "H.J. Lu" , Andy Lutomirski Cc: Yu-cheng Yu , the arch/x86 maintainers , "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , LKML , linux-doc@vger.kernel.org, Linux-MM , linux-arch , Linux API , Arnd Bergmann , Andy Lutomirski , Balbir Singh , Borislav Petkov , Cyrill Gorcunov , Dave Hansen , Eugene Syromiatnikov , Florian Weimer , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Peter Zijlstra , Randy Dunlap , "Ravi V. Shankar" , Vedvyas Shanbhogue , Dave Martin , x86-patch-review@intel.com List-ID: Message-ID: <20200309205952.Zkdcd650_f7KQDz8uLJx-kndO7uSfpWLUDj5rFGBLV8@z> On 3/9/20 1:54 PM, H.J. Lu wrote: >> If a program with the magic ELF CET flags missing can’t make a >> thread with IBT and/or SHSTK enabled, then I think we’ve made an >> error and should fix it. >> > A non-CET program can start a CET program and vice versa. Could we be specific here, please? HJ are you saying that: * CET program can execve() a non-CET program, and * a non-CET program can execve() a CET program ? That's obvious. But what are the rules for clone()? Should there be rules for mismatches for CET enabling between threads if a process (not child processes)?