We have a use case on a system where we have a systemd .service unit file that is using the SELinuxContext= [1] option to specify a context for the service being started. The same .service file (/lib/systemd/system/foo@.service) is used to start multiple instances of the same executable that are customized with a different drop-in .conf file for each. The context is customized in /lib/systemd/system/foo@.service file (based on using SELinuxContext=system_u:system_r:foo_%i_t:s0) [2]
We then create /etc/systemd/system/foo@bar.service.d/bar.conf so the final running process is in the domain foo_bar_t
We have created the following interface (in init.if) to meet our needs. The interface is very much like init_daemon_domain except for the use of spec_domtrans_pattern rather than domtrans_pattern because the automatic transition doesn't work in this case.
[1] The SELinuxContext option for systemd is explained https://www.freedesktop.org/software/systemd/man/systemd.exec.html
[2] The systemd %i (and other specifiers) along with drop-in files are explained https://www.freedesktop.org/software/systemd/man/systemd.unit.html
Signed-off-by: Dave Sugar <dsugar@tresys.com>
Those mmap() calls are non-essential, though. They're issued by
fdopen(), which can also fall back to read().
Since there are few reasons to grant read access to audit logs other
than for using ausearch, I've added the dontaudits directly to the
relevant read interfaces.
Note that not only kmod needs this permission, other libkmod consumers
like udev require it, too. Hence I'm adding the permission to the
relevant interfaces.
systemd relabels everything in /dev and /run after loading the policy.
In these directories there is a socket file for udev, /run/udev/control,
which is not allowed to be relabelled from tmpfs_t:
avc: denied { relabelfrom } for pid=1 comm="systemd"
name="control" dev="tmpfs" ino=7027
scontext=system_u:system_r:init_t tcontext=system_u:object_r:tmpfs_t
tclass=sock_file permissive=1
avc: denied { relabelto } for pid=1 comm="systemd" name="control"
dev="tmpfs" ino=7027 scontext=system_u:system_r:init_t
tcontext=system_u:object_r:udev_var_run_t tclass=sock_file
permissive=1
/run/tmpfiles.d directory (used by systemd-tmpfiles service) is also
relabelled.
This is currently denied:
avc: denied { create } for pid=1 comm="systemd" name="pts"
scontext=system_u:system_r:init_t
tcontext=system_u:object_r:devpts_t tclass=dir permissive=1
This is a minor update of the last attempt at this patch.
Changes in .fc to label /etc/rsyslog.d(/.*)? as syslog_conf_t so all rsyslog config files are labeled syslog_conf_t (not just /etc/r?syslog.conf). Update .te file to allow rsyslog to read the directory now labeled syslog_conf_t (files of this type were already readable). Final (and new) change is in logging_admin_syslog interface so files_etc_filetrans now includes the optional filename so /etc/r?syslog.conf would be labeled correctly when created in etc_t.
The overall goal of this patch is that a domain using the logging_admin_syslog is able to create/edit files in /etc/rsyslog.d and they get created as syslog_conf_t AND other files created in /etc (or other etc_t labeled directory) don't get created with the syslog_conf_t type as they are not necessarily syslog configuration files.
Dave Sugar
dsugar@tresys.com
Signed-off-by: Dave Sugar <dsugar@tresys.com>
Label RHEL specific systemd binaries /usr/lib/systemd/rhel* as initrc_exec_t.
Now in the proper location.
Signed-off-by: Dave Sugar <dsugar@tresys.com>
systemd tries to create /dev/pts directly with its context type
"devpts_t", but this is not allowed:
avc: denied { associate } for pid=1 comm="systemd" name="pts"
scontext=system_u:object_r:devpts_t
tcontext=system_u:object_r:device_t
tclass=filesystem permissive=1
The following patch creates two additional interfaces for tun_tap_device_t to grant only read or only write access (rather than both read and write access). It is possible to open a tap device for only reading or only writing and this allows policy to match that use.
Signed-off-by: Dave Sugar <dsugar@tresys.com>
The following patch allows systemd_nspawn_t to create directories under /tmp
and use them as mountpoints. Also allows systemd_nspawn_t to umount cgroup
filesystems.
Allows systemd_backlight_t to search /var/lib.
Commit 2e7553db63 ("Create / to /usr equivalence for bin, sbin, and
lib, from Russell Coker.") removed from corecommands.fc:
/usr/(.*/)?bin(/.*)? gen_context(system_u:object_r:bin_t,s0)
Consequently files like /usr/x86_64-w64-mingw32/bin/objdump get labeled
as usr_t:
$ matchpathcon /usr/x86_64-w64-mingw32/bin/objdump
/usr/x86_64-w64-mingw32/bin/objdump system_u:object_r:usr_t
Make such files labeled as bin_t again.
When auditctl logs a message to syslog, it needs to read /etc/localtime.
This is currently denied:
avc: denied { read } for pid=191 comm="auditctl" name="UTC"
dev="vda1" ino=394043 scontext=system_u:system_r:auditctl_t
tcontext=system_u:object_r:locale_t tclass=file permissive=1
avc: denied { open } for pid=191 comm="auditctl"
path="/usr/share/zoneinfo/UTC" dev="vda1" ino=394043
scontext=system_u:system_r:auditctl_t
tcontext=system_u:object_r:locale_t tclass=file permissive=1
This occurs for example at boot time when "/usr/bin/augenrules --load"
is run [1]. Here is an extract of "strace -s 256 -f /usr/bin/augenrules
--load":
[pid 635] execve("/sbin/auditctl", ["/sbin/auditctl", "-R",
"/etc/audit/audit.rules"], 0x1e77d80 /* 16 vars */) = 0
...
[pid 635] open("/etc/audit/audit.rules", O_RDONLY) = -1 ENOENT (No
such file or directory)
[pid 635] open("/etc/localtime", O_RDONLY|O_CLOEXEC) = 4
[pid 635] fstat(4, {st_mode=S_IFREG|0644, st_size=127, ...}) = 0
[pid 635] fstat(4, {st_mode=S_IFREG|0644, st_size=127, ...}) = 0
[pid 635] read(4, "TZif2\0\0\0\0\0\0\0\0\0\0\0"..., 4096) = 127
[pid 635] lseek(4, -71, SEEK_CUR) = 56
[pid 635] read(4, "TZif2\0\0\0\0\0\0\0\0\0\0\0", 4096) = 71
[pid 635] close(4) = 0
[pid 635] socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0) = 4
[pid 635] connect(4, {sa_family=AF_UNIX, sun_path="/dev/log"}, 110) = 0
[pid 635] sendto(4, "<14>Aug 12 08:59:53 auditctl: file
/etc/audit/audit.rules doesn't exist, skipping", 81, MSG_NOSIGNAL,
NULL, 0) = 81
[pid 635] exit_group(0) = ?
More precisely, auditctl uses vsyslog() from glibc, which uses
localtime_r() to fetch the time is in local timezone.
[1] On a systemd system, this command is automatically run by
auditd.service unit, cf.
https://github.com/linux-audit/audit-userspace/blob/v2.7.7/init.d/auditd.service#L21
Remove complement (~) and wildcard (*) in allow rules so that there are no
unintentional additions when new permissions are declared.
This patch does not add or remove permissions from any rules.
When a program uses init_module() to load a module, the kernel checks
for system:load_module permission in the process type [1].
For example when systemd loads ip_tables modules (since
1d3087978a),
the following AVC denial gets reported:
avc: denied { module_load } for pid=1 comm="systemd"
scontext=system_u:system_r:init_t tcontext=system_u:system_r:init_t
tclass=system permissive=1
[1] The relevant kernel code is selinux_kernel_module_from_file() in
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/security/selinux/hooks.c?h=v4.11#n3836
/* init_module */
if (file == NULL)
return avc_has_perm(sid, sid, SECCLASS_SYSTEM,
SYSTEM__MODULE_LOAD, NULL);
In this code, both source and target SIDs are current_sid().
Since Xen 4.7, /dev/xen/privcmd is used instead of /proc/xen/privcmd.
Add the device into the policy so `xenstored` can work.
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Not auditing this turns out to be the wrong choice for
several reasons.
For normal application functioning the user domain
should be able to create netlink_kobject_uvent_socket
sockets.
Signed-off-by: Guido Trentalancia <guido@trentalancia.com>
This won't match subdirectories of /usr/lib, but that shouldn't be a
problem, since we have "allow domain lib_t ..." anyway.
We can't match on "/usr/(.*/)?man(/.*)?", since that'd result in a few
false positives; in particular, the files
/usr/share/xmlto/format/docbook/man
/usr/share/bash-completion/completions/man
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>
Every Infiniband network will have a default pkey, so that is labeled.
The rest of the pkey configuration is network specific. The policy allows
access to the default and unlabeled pkeys for sysadm and staff users.
kernel_t is allowed access to all pkeys, which it needs to process and
route management datagrams.
Endports are all unlabeled by default, sysadm users are allowed to
manage the subnet on unlabeled endports. kernel_t is allowed to manage
the subnet on all ibendports, which is required for configuring the HCA.
This patch requires selinux series: "SELinux user space support for
Infiniband RDMA", due to the new ipkeycon labeling mechanism.
Signed-off-by: Daniel Jurgens <danielj@mellanox.com>
This is the base part of the policy needed to support libmtp (an
Initiator implementation of the Media Transfer Protocol).
Signed-off-by: Guido Trentalancia <guido at trentalancia.net>
Linux kernel commit da69a5306ab9 ("selinux: support distinctions among all
network address families") triggers a build error if a new address family
is added without defining a corresponding SELinux security class. As a
result, the smc_socket class was added to the kernel to resolve a build
failure as part of merge commit 3051bf36c25d that introduced AF_SMC circa
Linux 4.11. Define this security class and its access vector, note that it
is enabled as part of the extended_socket_class policy capability, and add
it to the socket_class_set macro.
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
This permission was added to the kernel in commit 791ec491c372
("prlimit,security,selinux: add a security hook for prlimit")
circa Linux 4.12 in order to control the ability to get the resource
limits of another process. It is only checked when acting on another
process, so getrlimit permission is not required for use of getrlimit(2).
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Setting this service option to 'full' or 'strict' will also remount the
/etc directory. Allow this in the policy.
This fixes the systemd-networkd service, but will also positively affect
any other service using the above hardening option.
Since app-admin/setools-4.1.0, some python internals try to create and
execute a file in /tmp during semanage initalization, causing semanage
to crash. Here's the backtrace (with the path
"/usr/lib64/python3.4/site-packages" replaced by "py" for brevity):
Traceback (most recent call last):
File "/usr/lib/python-exec/python3.4/semanage", line 28, in <module>
import seobject
File "py/seobject.py", line 34, in <module>
import sepolicy
File "py/sepolicy/__init__.py", line 8, in <module>
import setools
File "py/setools/__init__.py", line 77, in <module>
from .infoflow import InfoFlowAnalysis
File "py/setools/infoflow.py", line 22, in <module>
import networkx as nx
File "py/networkx/__init__.py", line 93, in <module>
import networkx.linalg
File "py/networkx/linalg/__init__.py", line 9, in <module>
from networkx.linalg.algebraicconnectivity import *
File "py/networkx/linalg/algebraicconnectivity.py", line 18, in <module>
from numpy import (array, asmatrix, asarray, dot, matrix, ndarray, ones,
File "py/numpy/__init__.py", line 180, in <module>
from . import add_newdocs
File "py/numpy/add_newdocs.py", line 13, in <module>
from numpy.lib import add_newdoc
File "py/numpy/lib/__init__.py", line 8, in <module>
from .type_check import *
File "py/numpy/lib/type_check.py", line 11, in <module>
import numpy.core.numeric as _nx
File "py/numpy/core/__init__.py", line 22, in <module>
from . import _internal # for freeze programs
File "py/numpy/core/_internal.py", line 14, in <module>
import ctypes
File "/usr/lib64/python3.4/ctypes/__init__.py", line 541, in <module>
_reset_cache()
File "/usr/lib64/python3.4/ctypes/__init__.py", line 280, in _reset_cache
CFUNCTYPE(c_int)(lambda: None)
MemoryError
Improve the initrc domain within the init module with some permissions
needed for a smoother boot.
Let the iptables init scripts read the iptables configuration.
Signed-off-by: Guido Trentalancia <guido@trentalancia.net>
Jason Zaman
Luis Ressel
Chris PeBenito
David Sugar
Nicolas Iooss
Christian Göttsche
Nicolas Iooss via refpolicy
Russell Coker
Krzysztof Nowicki
Anthony PERARD
Guido Trentalancia
Stephen Smalley
Daniel Jurgens
Guido Trentalancia