Kernel commit 6941857e82ae ("selinux: add a map permission check
for mmap") added a map permission check on mmap so that we can
distinguish memory mapped access (since it has different implications
for revocation). The purpose of a separate map permission check on
mmap(2) is to permit policy to prohibit memory mapping of specific files
for which we need to ensure that every access is revalidated, particularly
useful for scenarios where we expect the file to be relabeled at runtime
in order to reflect state changes (e.g. cross-domain solution, assured
pipeline without data copying). The kernel commit is anticipated to
be included in Linux 4.13.
This refpolicy change defines map permission for refpolicy. It mirrors
the definition in the kernel classmap by adding it to the common
definitions for files and sockets. This will break compatibility for
kernels that predate the dynamic class/perm mapping support (< 2.6.33,
< RHEL 6); on such kernels, one would instead need to add map permission
to the end of each file and socket access vector.
This change only allows map permission as needed, e.g. only in the
mmap_file_perms and exec_file_perms object permission sets
(since map is always required there) and only in specific interfaces
or modules where denials were observed in limited testing.
It is important to note that effective use of this permission requires
complete removal of unconfined, as otherwise unconfined domains will be
able to map all file types and therefore bypass the intended protection.
If we wanted to exclude map permission to all file types by default from
unconfined, we would need to add it to the list of permissions excluded from
files_unconfined_type in kernel/files.te.
Policies that depend on this permission not being allowed to specific file
types should also make use of neverallow rules to ensure that this is not
undermined by any allow rule, and ensure that they are performing neverallow
checking at policy build time (e.g. make validate) or runtime (e.g.
semanage.conf expand-check=1).
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
I believe that I have addressed all the issues Chris raised, so here's a newer
version of the patch which applies to today's git version.
Description: systemd-resolved, sessions, and tmpfiles patches
Author: Russell Coker <russell@coker.com.au>
Last-Update: 2017-03-26
Since /var/cache/man was previously labeled man_t, make sure that the old
interfaces with regard to man_t also support man_cache_t
Signed-off-by: Dominick Grift <dominick.grift@gmail.com>
This is based on Fedoras' miscfiles_cert_type implementation.
The idea was that openvpn needs to be able read home certificates (home_cert_t) which is not implemented in refpolicy yet, as well as generic cert_t certificates.
Note that openvpn is allowed to read all cert_types, as i know that it needs access to both generic cert_t as well as (future) home_cert_t. Dwalsh noted that other domains may need this as well but because i do not know exactly which domains i will not changes any other domains call to generic cert type interfaces.
Signed-off-by: Dominick Grift <domg472@gmail.com>
Luis Ressel
Chris PeBenito
Stephen Smalley
Nicolas Iooss
Elia Pinto
Chris PeBenito
Dominick Grift
Jeremy Solt
Dominick Grift