On 09/09/2019 12:12, James Morris wrote: > On Mon, 9 Sep 2019, Mickaël Salaün wrote: > >> >> On 06/09/2019 21:03, James Morris wrote: >>> On Fri, 6 Sep 2019, Jeff Layton wrote: >>> >>>> The fact that open and openat didn't vet unknown flags is really a bug. >>>> >>>> Too late to fix it now, of course, and as Aleksa points out, we've >>>> worked around that in the past. Now though, we have a new openat2 >>>> syscall on the horizon. There's little need to continue these sorts of >>>> hacks. >>>> >>>> New open flags really have no place in the old syscalls, IMO. >>> >>> Agree here. It's unfortunate but a reality and Linus will reject any such >>> changes which break existing userspace. >> >> Do you mean that adding new flags to open(2) is not possible? >> >> Does it means that unspecified behaviors are definitely part of the >> Linux specification and can't be fixed? > > This is my understanding. > >> >> As I said, O_MAYEXEC should be ignored if it is not supported by the >> kernel, which perfectly fit with the current open(2) flags behavior, and >> should also behave the same with openat2(2). > > The problem here is programs which are already using the value of > O_MAYEXEC, which will break. Hence, openat2(2). Well, it still depends on the sysctl, which doesn't enforce anything by default, hence doesn't break existing behavior, and this unused flags could be fixed/removed or reported by sysadmins or distro developers. -- Mickaël Salaün Les données à caractère personnel recueillies et traitées dans le cadre de cet échange, le sont à seule fin d’exécution d’une relation professionnelle et s’opèrent dans cette seule finalité et pour la durée nécessaire à cette relation. Si vous souhaitez faire usage de vos droits de consultation, de rectification et de suppression de vos données, veuillez contacter contact.rgpd@xxxxxxxxxxxxx. Si vous avez reçu ce message par erreur, nous vous remercions d’en informer l’expéditeur et de détruire le message. The personal data collected and processed during this exchange aims solely at completing a business relationship and is limited to the necessary duration of that relationship. If you wish to use your rights of consultation, rectification and deletion of your data, please contact: contact.rgpd@xxxxxxxxxxxxx. If you have received this message in error, we thank you for informing the sender and destroying the message.
