kernel_optimize_test/security
Jann Horn 4f72123da5 LSM: SafeSetID: verify transitive constrainedness
Someone might write a ruleset like the following, expecting that it
securely constrains UID 1 to UIDs 1, 2 and 3:

    1:2
    1:3

However, because no constraints are applied to UIDs 2 and 3, an attacker
with UID 1 can simply first switch to UID 2, then switch to any UID from
there. The secure way to write this ruleset would be:

    1:2
    1:3
    2:2
    3:3

, which uses "transition to self" as a way to inhibit the default-allow
policy without allowing anything specific.

This is somewhat unintuitive. To make sure that policy authors don't
accidentally write insecure policies because of this, let the kernel verify
that a new ruleset does not contain any entries that are constrained, but
transitively unconstrained.

Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Micah Morton <mortonm@chromium.org>
2019-07-15 08:07:51 -07:00
..
apparmor
integrity
keys
loadpin security/loadpin improvement 2019-07-11 14:42:44 -07:00
safesetid LSM: SafeSetID: verify transitive constrainedness 2019-07-15 08:07:51 -07:00
selinux
smack
tomoyo
yama
commoncap.c
device_cgroup.c
inode.c
Kconfig
Kconfig.hardening mm: security: introduce init_on_alloc=1 and init_on_free=1 boot options 2019-07-12 11:05:46 -07:00
lsm_audit.c
Makefile
min_addr.c
security.c