4f72123da5
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>
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|---|---|---|
| .. | ||
| apparmor | ||
| integrity | ||
| keys | ||
| loadpin | ||
| safesetid | ||
| selinux | ||
| smack | ||
| tomoyo | ||
| yama | ||
| commoncap.c | ||
| device_cgroup.c | ||
| inode.c | ||
| Kconfig | ||
| Kconfig.hardening | ||
| lsm_audit.c | ||
| Makefile | ||
| min_addr.c | ||
| security.c | ||