On 12/20/20 11:40 AM, Richard Haines wrote:
On Sun, 2020-12-20 at 10:01 -0500, Chris PeBenito wrote:
On 12/20/20 7:31 AM, Richard Haines wrote:
On Sat, 2020-12-19 at 15:49 -0500, Chris PeBenito wrote:
On 12/18/20 10:03 AM, Richard Haines wrote:
When building a monolithic policy with 'make load', the
selinux_config(5) file 'SELINUXTYPE' entry determines what
policy
is loaded as load_policy(8) does not take a path value (it
always
loads
the active system policy as defined by /etc/selinux/config).
Currently it is possible to load the wrong binary policy, for
example if
the Reference Policy source is located at:
/etc/selinux/refpolicy
and the /etc/selinux/config file has the following entry:
SELINUXTYPE=targeted
Then the /etc/selinux/targeted/policy/policy.<ver> is loaded
when
'make load' is executed.
Another example is that if the Reference Policy source is
located
at:
/tmp/custom-rootfs/etc/selinux/refpolicy
and the /etc/selinux/config file has the following entry:
SELINUXTYPE=refpolicy
Then the /etc/selinux/refpolicy/policy/policy.<ver> is loaded
when
'make DESTDIR=/tmp/custom-rootfs load' is executed (not the
/tmp/custom-rootfs/etc/selinux/refpolicy/policy/policy.<ver>
that
the
developer thought would be loaded).
Resolve these issues by using selinux_path(3) to resolve the
policy
root,
then checking the selinux_config(5) file for the appropriate
SELINUXTYPE
entry.
Remove the '@touch $(tmpdir)/load' line as the file is never
referenced.
Signed-off-by: Richard Haines <richard_c_haines@xxxxxxxxxxxxxx>
---
V2 Changes: Use $(error .. instead of NO_LOAD logic. Use python
script to
find selinux path not sestatus. Reword error messages.
Makefile | 1 +
Rules.monolithic | 15 ++++++++++++++-
support/selinux_path.py | 13 +++++++++++++
3 files changed, 28 insertions(+), 1 deletion(-)
create mode 100644 support/selinux_path.py
diff --git a/Makefile b/Makefile
index 6ba215f1..e49d43d0 100644
--- a/Makefile
+++ b/Makefile
@@ -97,6 +97,7 @@ genxml := $(PYTHON) $(support)/segenxml.py
gendoc := $(PYTHON) $(support)/sedoctool.py
genperm := $(PYTHON) $(support)/genclassperms.py
policyvers := $(PYTHON) $(support)/policyvers.py
+selinux_path := $(PYTHON) $(support)/selinux_path.py
fcsort := $(PYTHON) $(support)/fc_sort.py
setbools := $(AWK) -f $(support)/set_bools_tuns.awk
get_type_attr_decl := $(SED) -r -f
$(support)/get_type_attr_decl.sed
diff --git a/Rules.monolithic b/Rules.monolithic
index a8ae98d1..cd065362 100644
--- a/Rules.monolithic
+++ b/Rules.monolithic
@@ -42,6 +42,12 @@ vpath %.te $(all_layers)
vpath %.if $(all_layers)
vpath %.fc $(all_layers)
+# load_policy(8) loads policy from
<SELINUX_PATH>/<SELINUXTYPE>/policy/policy.<ver>
+# It does this by reading the <SELINUX_PATH>/config file and
using
the
+# SELINUX_PATH/SELINUXTYPE entries to form the initial path.
+SELINUX_PATH := $(shell $(selinux_path))
+SELINUXTYPE := $(strip $(shell $(AWK) -F= '/^SELINUXTYPE/{
print
$$2 }' $(SELINUX_PATH)/config))
+
########################################
#
# default action: build policy locally
@@ -91,9 +97,16 @@ endif
# Load the binary policy
#
reload $(tmpdir)/load: $(loadpath) $(fcpath) $(appfiles)
+ifneq ($(SELINUXTYPE),$(NAME))
+ $(error Cannot load policy as $(SELINUX_PATH)/config
file
contains SELINUXTYPE=$(SELINUXTYPE) - \
+ Edit $(SELINUX_PATH)/config and set
"SELINUXTYPE=$(NAME)")
+endif
+ifneq ($(topdir),$(SELINUX_PATH))
+ $(error Cannot load policy as policy root MUST be
$(SELINUX_PATH)/$(NAME) - \
+ Current policy root is: $(topdir)/$(NAME))
+endif
@echo "Loading $(NAME) $(loadpath)"
$(verbose) $(LOADPOLICY) -q $(loadpath)
- @touch $(tmpdir)/load
########################################
#
diff --git a/support/selinux_path.py b/support/selinux_path.py
new file mode 100644
index 00000000..b663ff09
--- /dev/null
+++ b/support/selinux_path.py
@@ -0,0 +1,13 @@
+#!/usr/bin/env python3
+
+try:
+ import warnings
+ with warnings.catch_warnings():
+ warnings.filterwarnings("ignore",
category=PendingDeprecationWarning)
+ import selinux
+
+ if selinux.is_selinux_enabled():
+ # Strip the trailing '/'
+ print(selinux.selinux_path()[:-1])
Why not use selinux.selinux_binary_policy_path()? Then you don't
need
to parse
for SELINUXTYPE above.
Because it has more information than needed. How about using
selinux.selinux_policy_root() to give:
# load_policy(8) loads policy from
<POLICY_ROOT>/policy/policy.<ver>
# It does this by reading the <SELINUX_PATH>/config file and using
the
# SELINUX_PATH/SELINUXTYPE entry to form the <POLICY_ROOT>.
POLICY_ROOT := $(shell $(selinux_policy_root))
SELINUXTYPE := $(shell basename $(POLICY_ROOT))
SELINUX_PATH := $(shell dirname $(POLICY_ROOT))
On second thought, isn't another way of doing the check:
selinux.selinux_binary_policy_path() + "." + POLICYVER ==
$(loadpath)?
Yes I could, however that accounts for only one of the checks:
Cannot load policy as policy root MUST be ...
The other check uses SELINUXTYPE against $NAME to see if the config
file has the correct entry:
Cannot load policy as $(SELINUX_PATH)/config file ...
I could just use one test and say that the policy must be based at
/etc/selinux/$(NAME) plus the /etc/selinux/config file SELINUXTYPE
entry must be $(NAME) ???
Since the Makefile creates $(loadpath) to be $(topdir)/$NAME/policy/policy.$ver,
and selinux.selinux_binary_policy_path() takes into account SELINUXTYPE, the
only reason the $topdir ($DESTDIR/etc/selinux), would be a problem is if
DESTDIR is set. We should instead fail the load if DESTDIR is set. If the user
alters the $(topdir) of the Makefile to change /etc/selinux into something else,
that is undefined behavior since lowercase variables aren't meant to be altered
by users. I see no reason to check that case.
--
Chris PeBenito
