Am 10.07.2015 um 21:30 schrieb Greg Kroah-Hartman: > On Fri, Jul 10, 2015 at 08:24:41PM +0200, Richard Weinberger wrote: >> Am 10.07.2015 um 18:17 schrieb Eric W. Biederman: >>> >>> Today proc and sysfs do not contain any executable files. Several >>> applications today mount proc or sysfs without noexec and nosuid and >>> then depend on there being no exectuables files on proc or sysfs. >>> Having any executable files show on proc or sysfs would cause >>> a user space visible regression, and most likely security problems. >>> >>> Therefore commit to never allowing executables on proc and sysfs by >>> adding a new flag to mark them as filesystems without executables and >>> enforce that flag. >>> >>> Test the flag where MNT_NOEXEC is tested today, so that the only user >>> visible effect will be that exectuables will be treated as if the >>> execute bit is cleared. >>> >>> The filesystems proc and sysfs do not currently incoporate any >>> executable files so this does not result in any user visible effects. >>> >>> This makes it unnecessary to vet changes to proc and sysfs tightly for >>> adding exectuable files or changes to chattr that would modify >>> existing files, as no matter what the individual file say they will >>> not be treated as exectuable files by the vfs. >>> >>> Not having to vet changes to closely is important as without this we >>> are only one proc_create call (or another goof up in the >>> implementation of notify_change) from having problematic executables >>> on proc. Those mistakes are all too easy to make and would create >>> a situation where there are security issues or the assumptions of >>> some program having to be broken (and cause userspace regressions). >> >> Would it make sense to add SB_I_NOEXEC to more pseudo filesystems? >> Say pstore or devpts? > > And configfs and cgroupfs? Yep. Any filesystem where exectuables do not make sense. :-) Thanks, //richard _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/containers
