linux/security
Eric W. Biederman 90f8572b0f vfs: Commit to never having exectuables on proc and sysfs.
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).

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2015-07-10 10:39:25 -05:00
..
apparmor Minor merge needed, due to function move. 2015-07-01 10:49:25 -07:00
integrity Minor merge needed, due to function move. 2015-07-01 10:49:25 -07:00
keys switch keyctl_instantiate_key_common() to iov_iter 2015-04-11 22:27:12 -04:00
selinux Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2015-07-03 15:20:57 -07:00
smack Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2015-07-03 15:20:57 -07:00
tomoyo LSM: Switch to lists of hooks 2015-05-12 15:00:41 +10:00
yama LSM: Switch to lists of hooks 2015-05-12 15:00:41 +10:00
commoncap.c LSM: Switch to lists of hooks 2015-05-12 15:00:41 +10:00
device_cgroup.c cgroup: rename cgroup_subsys->base_cftypes to ->legacy_cftypes 2014-07-15 11:05:09 -04:00
inode.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-07-04 19:36:06 -07:00
Kconfig kernel: conditionally support non-root users, groups and capabilities 2015-04-15 16:35:22 -07:00
lsm_audit.c Merge branch 'upstream' of git://git.infradead.org/users/pcmoore/audit 2015-06-27 13:53:16 -07:00
Makefile LSM: Switch to lists of hooks 2015-05-12 15:00:41 +10:00
min_addr.c
security.c vfs: Commit to never having exectuables on proc and sysfs. 2015-07-10 10:39:25 -05:00