Run Treble sepolicy tests at build time

Bug: 37008075
Test: build policy on Marlin
Change-Id: I53748f94c5df66fa17a53e7d0bed1be6b8603544
(cherry picked from commit e1ddc6df75d61dd8dc9a1ea00e1da60389f55556)
diff --git a/tests/treble_sepolicy_tests.py b/tests/treble_sepolicy_tests.py
new file mode 100644
index 0000000..3d6a480
--- /dev/null
+++ b/tests/treble_sepolicy_tests.py
@@ -0,0 +1,274 @@
+from optparse import OptionParser
+from optparse import Option, OptionValueError
+import os
+import policy
+import re
+import sys
+
+DEBUG=False
+
+'''
+Use file_contexts and policy to verify Treble requirements
+are not violated.
+'''
+###
+# Differentiate between domains that are part of the core Android platform and
+# domains introduced by vendors
+coreAppdomain = {
+        'bluetooth',
+        'ephemeral_app',
+        'isolated_app',
+        'nfc',
+        'platform_app',
+        'priv_app',
+        'radio',
+        'shared_relro',
+        'shell',
+        'system_app',
+        'untrusted_app',
+        'untrusted_app_25',
+        'untrusted_v2_app',
+        }
+coredomainWhitelist = {
+        'adbd',
+        'kernel',
+        'postinstall',
+        'postinstall_dexopt',
+        'recovery',
+        'system_server',
+        }
+coredomainWhitelist |= coreAppdomain
+
+class scontext:
+    def __init__(self):
+        self.fromSystem = False
+        self.fromVendor = False
+        self.coredomain = False
+        self.appdomain = False
+        self.attributes = set()
+        self.entrypoints = []
+        self.entrypointpaths = []
+
+def PrintScontexts():
+    for d in sorted(alldomains.keys()):
+        sctx = alldomains[d]
+        print d
+        print "\tcoredomain="+str(sctx.coredomain)
+        print "\tappdomain="+str(sctx.appdomain)
+        print "\tfromSystem="+str(sctx.fromSystem)
+        print "\tfromVendor="+str(sctx.fromVendor)
+        print "\tattributes="+str(sctx.attributes)
+        print "\tentrypoints="+str(sctx.entrypoints)
+        print "\tentrypointpaths="
+        if sctx.entrypointpaths is not None:
+            for path in sctx.entrypointpaths:
+                print "\t\t"+str(path)
+
+alldomains = {}
+coredomains = set()
+appdomains = set()
+vendordomains = set()
+
+###
+# Check whether the regex will match a file path starting with the provided
+# prefix
+#
+# Compares regex entries in file_contexts with a path prefix. Regex entries
+# are often more specific than this file prefix. For example, the regex could
+# be /system/bin/foo\.sh and the prefix could be /system. This function
+# loops over the regex removing characters from the end until
+# 1) there is a match - return True or 2) run out of characters - return
+#    False.
+#
+def MatchPathPrefix(pathregex, prefix):
+    for i in range(len(pathregex), 0, -1):
+        try:
+            pattern = re.compile('^' + pathregex[0:i] + "$")
+        except:
+            continue
+        if pattern.match(prefix):
+            return True
+    return False
+
+def GetAllDomains(pol):
+    global alldomains
+    for result in pol.QueryTypeAttribute("domain", True):
+        alldomains[result] = scontext()
+
+def GetAppDomains():
+    global appdomains
+    global alldomains
+    for d in alldomains:
+        # The application of the "appdomain" attribute is trusted because core
+        # selinux policy contains neverallow rules that enforce that only zygote
+        # and runas spawned processes may transition to processes that have
+        # the appdomain attribute.
+        if "appdomain" in alldomains[d].attributes:
+            alldomains[d].appdomain = True
+            appdomains.add(d)
+
+
+def GetCoreDomains():
+    global alldomains
+    global coredomains
+    for d in alldomains:
+        # TestCoredomainViolators will verify if coredomain was incorrectly
+        # applied.
+        if "coredomain" in alldomains[d].attributes:
+            alldomains[d].coredomain = True
+            coredomains.add(d)
+        # check whether domains are executed off of /system or /vendor
+        if d in coredomainWhitelist:
+            continue
+        # TODO, add checks to prevent app domains from being incorrectly
+        # labeled as coredomain. Apps don't have entrypoints as they're always
+        # dynamically transitioned to by zygote.
+        if d in appdomains:
+            continue
+        if not alldomains[d].entrypointpaths:
+            continue
+        for path in alldomains[d].entrypointpaths:
+            # Processes with entrypoint on /system
+            if ((MatchPathPrefix(path, "/system") and not
+                    MatchPathPrefix(path, "/system/vendor")) or
+                    MatchPathPrefix(path, "/init") or
+                    MatchPathPrefix(path, "/charger")):
+                alldomains[d].fromSystem = True
+            # Processes with entrypoint on /vendor or /system/vendor
+            if (MatchPathPrefix(path, "/vendor") or
+                    MatchPathPrefix(path, "/system/vendor")):
+                alldomains[d].fromVendor = True
+
+###
+# Add the entrypoint type and path(s) to each domain.
+#
+def GetDomainEntrypoints(pol):
+    global alldomains
+    for x in pol.QueryTERule(tclass="file", perms=["entrypoint"]):
+        if not x.sctx in alldomains:
+            continue
+        alldomains[x.sctx].entrypoints.append(str(x.tctx))
+        # postinstall_file represents a special case specific to A/B OTAs.
+        # Update_engine mounts a partition and relabels it postinstall_file.
+        # There is no file_contexts entry associated with postinstall_file
+        # so skip the lookup.
+        if x.tctx == "postinstall_file":
+            continue
+        entrypointpath = pol.QueryFc(x.tctx)
+        if not entrypointpath:
+            continue
+        alldomains[x.sctx].entrypointpaths.extend(entrypointpath)
+###
+# Get attributes associated with each domain
+#
+def GetAttributes(pol):
+    global alldomains
+    for domain in alldomains:
+        for result in pol.QueryTypeAttribute(domain, False):
+            alldomains[domain].attributes.add(result)
+
+def setup(pol):
+    GetAllDomains(pol)
+    GetAttributes(pol)
+    GetDomainEntrypoints(pol)
+    GetAppDomains()
+    GetCoreDomains()
+
+#############################################################
+# Tests
+#############################################################
+def TestCoredomainViolations():
+    global alldomains
+    # verify that all domains launched from /system have the coredomain
+    # attribute
+    ret = ""
+    violators = []
+    for d in alldomains:
+        domain = alldomains[d]
+        if domain.fromSystem and "coredomain" not in domain.attributes:
+                violators.append(d);
+    if len(violators) > 0:
+        ret += "The following domain(s) must be associated with the "
+        ret += "\"coredomain\" attribute because they are executed off of "
+        ret += "/system:\n"
+        ret += " ".join(str(x) for x in sorted(violators)) + "\n"
+
+    # verify that all domains launched form /vendor do not have the coredomain
+    # attribute
+    violators = []
+    for d in alldomains:
+        domain = alldomains[d]
+        if domain.fromVendor and "coredomain" in domain.attributes:
+            violators.append(d)
+    if len(violators) > 0:
+        ret += "The following domains must not be associated with the "
+        ret += "\"coredomain\" attribute because they are executed off of "
+        ret += "/vendor or /system/vendor:\n"
+        ret += " ".join(str(x) for x in sorted(violators)) + "\n"
+
+    return ret
+
+###
+# extend OptionParser to allow the same option flag to be used multiple times.
+# This is used to allow multiple file_contexts files and tests to be
+# specified.
+#
+class MultipleOption(Option):
+    ACTIONS = Option.ACTIONS + ("extend",)
+    STORE_ACTIONS = Option.STORE_ACTIONS + ("extend",)
+    TYPED_ACTIONS = Option.TYPED_ACTIONS + ("extend",)
+    ALWAYS_TYPED_ACTIONS = Option.ALWAYS_TYPED_ACTIONS + ("extend",)
+
+    def take_action(self, action, dest, opt, value, values, parser):
+        if action == "extend":
+            values.ensure_value(dest, []).append(value)
+        else:
+            Option.take_action(self, action, dest, opt, value, values, parser)
+
+Tests = ["CoredomainViolators"]
+
+if __name__ == '__main__':
+    usage = "sepolicy-trebletests -f nonplat_file_contexts -f "
+    usage +="plat_file_contexts -p policy [--test test] [--help]"
+    parser = OptionParser(option_class=MultipleOption, usage=usage)
+    parser.add_option("-f", "--file_contexts", dest="file_contexts",
+            metavar="FILE", action="extend", type="string")
+    parser.add_option("-p", "--policy", dest="policy", metavar="FILE")
+    parser.add_option("-l", "--library-path", dest="libpath", metavar="FILE")
+    parser.add_option("-t", "--test", dest="test", action="extend",
+            help="Test options include "+str(Tests))
+
+    (options, args) = parser.parse_args()
+
+    if not options.libpath:
+        sys.exit("Must specify path to host libraries\n" + parser.usage)
+    if not os.path.exists(options.libpath):
+        sys.exit("Error: library-path " + options.libpath + " does not exist\n"
+                + parser.usage)
+
+    if not options.policy:
+        sys.exit("Must specify monolithic policy file\n" + parser.usage)
+    if not os.path.exists(options.policy):
+        sys.exit("Error: policy file " + options.policy + " does not exist\n"
+                + parser.usage)
+
+    if not options.file_contexts:
+        sys.exit("Error: Must specify file_contexts file(s)\n" + parser.usage)
+    for f in options.file_contexts:
+        if not os.path.exists(f):
+            sys.exit("Error: File_contexts file " + f + " does not exist\n" +
+                    parser.usage)
+
+    pol = policy.Policy(options.policy, options.file_contexts, options.libpath)
+    setup(pol)
+
+    if DEBUG:
+        PrintScontexts()
+
+    results = ""
+    # If an individual test is not specified, run all tests.
+    if options.test is None or "CoredomainViolations" in options.tests:
+        results += TestCoredomainViolations()
+
+    if len(results) > 0:
+        sys.exit(results)