668e74f6f4
We need to be able to access app data files from core domains such as installd even for vendor apps. Those file types should not be core_data_file_type, so we explicitly exempty app_data_file_type as well as core_data_file_type from the relevant neverallows. To prevent misuse of the attribute, add a test to check it is not applied to anything in file_contexts. Exempt the existing violators in system policy for now. Test: Builds Test: Adding a type with just "file_type, data_file_type, app_data_file_type" works Test: New test successfully catches violators. Bug: 171795911 Change-Id: I07bf3ec3db615f8b7a33d8235da5e6d8e2508975
450 lines
18 KiB
Python
450 lines
18 KiB
Python
from ctypes import *
|
|
import re
|
|
import os
|
|
import sys
|
|
import platform
|
|
import fc_sort
|
|
|
|
###
|
|
# 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 MatchPathPrefixes(pathregex, Prefixes):
|
|
for Prefix in Prefixes:
|
|
if MatchPathPrefix(pathregex, Prefix):
|
|
return True
|
|
return False
|
|
|
|
class TERule:
|
|
def __init__(self, rule):
|
|
data = rule.split(',')
|
|
self.flavor = data[0]
|
|
self.sctx = data[1]
|
|
self.tctx = data[2]
|
|
self.tclass = data[3]
|
|
self.perms = set((data[4].strip()).split(' '))
|
|
self.rule = rule
|
|
|
|
class Policy:
|
|
__ExpandedRules = set()
|
|
__Rules = set()
|
|
__FcDict = None
|
|
__FcSorted = None
|
|
__GenfsDict = None
|
|
__libsepolwrap = None
|
|
__policydbP = None
|
|
__BUFSIZE = 2048
|
|
|
|
def AssertPathTypesDoNotHaveAttr(self, MatchPrefix, DoNotMatchPrefix, Attr, ExcludedTypes = []):
|
|
# Query policy for the types associated with Attr
|
|
TypesPol = self.QueryTypeAttribute(Attr, True) - set(ExcludedTypes)
|
|
# Search file_contexts to find types associated with input paths.
|
|
TypesFc, Files = self.__GetTypesAndFilesByFilePathPrefix(MatchPrefix, DoNotMatchPrefix)
|
|
violators = TypesFc.intersection(TypesPol)
|
|
ret = ""
|
|
if len(violators) > 0:
|
|
ret += "The following types on "
|
|
ret += " ".join(str(x) for x in sorted(MatchPrefix))
|
|
ret += " must not be associated with the "
|
|
ret += "\"" + Attr + "\" attribute: "
|
|
ret += " ".join(str(x) for x in sorted(violators)) + "\n"
|
|
ret += " corresponding to files: "
|
|
ret += " ".join(str(x) for x in sorted(Files)) + "\n"
|
|
return ret
|
|
|
|
# Check that all types for "filesystem" have "attribute" associated with them
|
|
# for types labeled in genfs_contexts.
|
|
def AssertGenfsFilesystemTypesHaveAttr(self, Filesystem, Attr):
|
|
TypesPol = self.QueryTypeAttribute(Attr, True)
|
|
TypesGenfs = self.__GenfsDict[Filesystem]
|
|
violators = TypesGenfs.difference(TypesPol)
|
|
|
|
ret = ""
|
|
if len(violators) > 0:
|
|
ret += "The following types in " + Filesystem
|
|
ret += " must be associated with the "
|
|
ret += "\"" + Attr + "\" attribute: "
|
|
ret += " ".join(str(x) for x in sorted(violators)) + "\n"
|
|
return ret
|
|
|
|
# Check that path prefixes that match MatchPrefix, and do not Match
|
|
# DoNotMatchPrefix have the attribute Attr.
|
|
# For example assert that all types in /sys, and not in /sys/kernel/debugfs
|
|
# have the sysfs_type attribute.
|
|
def AssertPathTypesHaveAttr(self, MatchPrefix, DoNotMatchPrefix, Attr):
|
|
# Query policy for the types associated with Attr
|
|
TypesPol = self.QueryTypeAttribute(Attr, True)
|
|
# Search file_contexts to find paths/types that should be associated with
|
|
# Attr.
|
|
TypesFc, Files = self.__GetTypesAndFilesByFilePathPrefix(MatchPrefix, DoNotMatchPrefix)
|
|
violators = TypesFc.difference(TypesPol)
|
|
|
|
ret = ""
|
|
if len(violators) > 0:
|
|
ret += "The following types on "
|
|
ret += " ".join(str(x) for x in sorted(MatchPrefix))
|
|
ret += " must be associated with the "
|
|
ret += "\"" + Attr + "\" attribute: "
|
|
ret += " ".join(str(x) for x in sorted(violators)) + "\n"
|
|
ret += " corresponding to files: "
|
|
ret += " ".join(str(x) for x in sorted(Files)) + "\n"
|
|
return ret
|
|
|
|
def AssertPropertyOwnersAreExclusive(self):
|
|
systemProps = self.QueryTypeAttribute('system_property_type', True)
|
|
vendorProps = self.QueryTypeAttribute('vendor_property_type', True)
|
|
violators = systemProps.intersection(vendorProps)
|
|
ret = ""
|
|
if len(violators) > 0:
|
|
ret += "The following types have both system_property_type "
|
|
ret += "and vendor_property_type: "
|
|
ret += " ".join(str(x) for x in sorted(violators)) + "\n"
|
|
return ret
|
|
|
|
# Return all file_contexts entries that map to the input Type.
|
|
def QueryFc(self, Type):
|
|
if Type in self.__FcDict:
|
|
return self.__FcDict[Type]
|
|
else:
|
|
return None
|
|
|
|
# Return all attributes associated with a type if IsAttr=False or
|
|
# all types associated with an attribute if IsAttr=True
|
|
def QueryTypeAttribute(self, Type, IsAttr):
|
|
TypeIterP = self.__libsepolwrap.init_type_iter(self.__policydbP,
|
|
create_string_buffer(Type), IsAttr)
|
|
if (TypeIterP == None):
|
|
sys.exit("Failed to initialize type iterator")
|
|
buf = create_string_buffer(self.__BUFSIZE)
|
|
TypeAttr = set()
|
|
while True:
|
|
ret = self.__libsepolwrap.get_type(buf, self.__BUFSIZE,
|
|
self.__policydbP, TypeIterP)
|
|
if ret == 0:
|
|
TypeAttr.add(buf.value)
|
|
continue
|
|
if ret == 1:
|
|
break;
|
|
# We should never get here.
|
|
sys.exit("Failed to import policy")
|
|
self.__libsepolwrap.destroy_type_iter(TypeIterP)
|
|
return TypeAttr
|
|
|
|
def __TERuleMatch(self, Rule, **kwargs):
|
|
# Match source type
|
|
if ("scontext" in kwargs and
|
|
len(kwargs['scontext']) > 0 and
|
|
Rule.sctx not in kwargs['scontext']):
|
|
return False
|
|
# Match target type
|
|
if ("tcontext" in kwargs and
|
|
len(kwargs['tcontext']) > 0 and
|
|
Rule.tctx not in kwargs['tcontext']):
|
|
return False
|
|
# Match target class
|
|
if ("tclass" in kwargs and
|
|
len(kwargs['tclass']) > 0 and
|
|
not bool(set([Rule.tclass]) & kwargs['tclass'])):
|
|
return False
|
|
# Match any perms
|
|
if ("perms" in kwargs and
|
|
len(kwargs['perms']) > 0 and
|
|
not bool(Rule.perms & kwargs['perms'])):
|
|
return False
|
|
return True
|
|
|
|
# resolve a type to its attributes or
|
|
# resolve an attribute to its types and attributes
|
|
# For example if scontext is the domain attribute, then we need to
|
|
# include all types with the domain attribute such as untrusted_app and
|
|
# priv_app and all the attributes of those types such as appdomain.
|
|
def ResolveTypeAttribute(self, Type):
|
|
types = self.GetAllTypes(False)
|
|
attributes = self.GetAllTypes(True)
|
|
|
|
if Type in types:
|
|
return self.QueryTypeAttribute(Type, False)
|
|
elif Type in attributes:
|
|
TypesAndAttributes = set()
|
|
Types = self.QueryTypeAttribute(Type, True)
|
|
TypesAndAttributes |= Types
|
|
for T in Types:
|
|
TypesAndAttributes |= self.QueryTypeAttribute(T, False)
|
|
return TypesAndAttributes
|
|
else:
|
|
return set()
|
|
|
|
# Return all TERules that match:
|
|
# (any scontext) or (any tcontext) or (any tclass) or (any perms),
|
|
# perms.
|
|
# Any unspecified paramenter will match all.
|
|
#
|
|
# Example: QueryTERule(tcontext=["foo", "bar"], perms=["entrypoint"])
|
|
# Will return any rule with:
|
|
# (tcontext="foo" or tcontext="bar") and ("entrypoint" in perms)
|
|
def QueryTERule(self, **kwargs):
|
|
if len(self.__Rules) == 0:
|
|
self.__InitTERules()
|
|
|
|
# add any matching types and attributes for scontext and tcontext
|
|
if ("scontext" in kwargs and len(kwargs['scontext']) > 0):
|
|
scontext = set()
|
|
for sctx in kwargs['scontext']:
|
|
scontext |= self.ResolveTypeAttribute(sctx)
|
|
kwargs['scontext'] = scontext
|
|
if ("tcontext" in kwargs and len(kwargs['tcontext']) > 0):
|
|
tcontext = set()
|
|
for tctx in kwargs['tcontext']:
|
|
tcontext |= self.ResolveTypeAttribute(tctx)
|
|
kwargs['tcontext'] = tcontext
|
|
for Rule in self.__Rules:
|
|
if self.__TERuleMatch(Rule, **kwargs):
|
|
yield Rule
|
|
|
|
# Same as QueryTERule but only using the expanded ruleset.
|
|
# i.e. all attributes have been expanded to their various types.
|
|
def QueryExpandedTERule(self, **kwargs):
|
|
if len(self.__ExpandedRules) == 0:
|
|
self.__InitExpandedTERules()
|
|
for Rule in self.__ExpandedRules:
|
|
if self.__TERuleMatch(Rule, **kwargs):
|
|
yield Rule
|
|
|
|
def GetAllTypes(self, isAttr):
|
|
TypeIterP = self.__libsepolwrap.init_type_iter(self.__policydbP, None, isAttr)
|
|
if (TypeIterP == None):
|
|
sys.exit("Failed to initialize type iterator")
|
|
buf = create_string_buffer(self.__BUFSIZE)
|
|
AllTypes = set()
|
|
while True:
|
|
ret = self.__libsepolwrap.get_type(buf, self.__BUFSIZE,
|
|
self.__policydbP, TypeIterP)
|
|
if ret == 0:
|
|
AllTypes.add(buf.value)
|
|
continue
|
|
if ret == 1:
|
|
break;
|
|
# We should never get here.
|
|
sys.exit("Failed to import policy")
|
|
self.__libsepolwrap.destroy_type_iter(TypeIterP)
|
|
return AllTypes
|
|
|
|
def __ExactMatchPathPrefix(self, pathregex, prefix):
|
|
pattern = re.compile('^' + pathregex + "$")
|
|
if pattern.match(prefix):
|
|
return True
|
|
return False
|
|
|
|
# Return a tuple (prefix, i) where i is the index of the most specific
|
|
# match of prefix in the sorted file_contexts. This is useful for limiting a
|
|
# file_contexts search to matches that are more specific and omitting less
|
|
# specific matches. For example, finding all matches to prefix /data/vendor
|
|
# should not include /data(/.*)? if /data/vendor(/.*)? is also specified.
|
|
def __FcSortedIndex(self, prefix):
|
|
index = 0
|
|
for i in range(0, len(self.__FcSorted)):
|
|
if self.__ExactMatchPathPrefix(self.__FcSorted[i].path, prefix):
|
|
index = i
|
|
return prefix, index
|
|
|
|
# Return a tuple of (path, Type) for all matching paths. Use the sorted
|
|
# file_contexts and index returned from __FcSortedIndex() to limit results
|
|
# to results that are more specific than the prefix.
|
|
def __MatchPathPrefixTypes(self, prefix, index):
|
|
PathType = []
|
|
for i in range(index, len(self.__FcSorted)):
|
|
if MatchPathPrefix(self.__FcSorted[i].path, prefix):
|
|
PathType.append((self.__FcSorted[i].path, self.__FcSorted[i].Type))
|
|
return PathType
|
|
|
|
# Return types that match MatchPrefixes but do not match
|
|
# DoNotMatchPrefixes
|
|
def __GetTypesAndFilesByFilePathPrefix(self, MatchPrefixes, DoNotMatchPrefixes):
|
|
Types = set()
|
|
Files = set()
|
|
|
|
MatchPrefixesWithIndex = []
|
|
for MatchPrefix in MatchPrefixes:
|
|
MatchPrefixesWithIndex.append(self.__FcSortedIndex(MatchPrefix))
|
|
|
|
for MatchPrefixWithIndex in MatchPrefixesWithIndex:
|
|
PathTypes = self.__MatchPathPrefixTypes(*MatchPrefixWithIndex)
|
|
for PathType in PathTypes:
|
|
if MatchPathPrefixes(PathType[0], DoNotMatchPrefixes):
|
|
continue
|
|
Types.add(PathType[1])
|
|
Files.add(PathType[0])
|
|
return Types, Files
|
|
|
|
def __GetTERules(self, policydbP, avtabIterP, Rules):
|
|
if Rules is None:
|
|
Rules = set()
|
|
buf = create_string_buffer(self.__BUFSIZE)
|
|
ret = 0
|
|
while True:
|
|
ret = self.__libsepolwrap.get_allow_rule(buf, self.__BUFSIZE,
|
|
policydbP, avtabIterP)
|
|
if ret == 0:
|
|
Rule = TERule(buf.value)
|
|
Rules.add(Rule)
|
|
continue
|
|
if ret == 1:
|
|
break;
|
|
# We should never get here.
|
|
sys.exit("Failed to import policy")
|
|
|
|
def __InitTERules(self):
|
|
avtabIterP = self.__libsepolwrap.init_avtab(self.__policydbP)
|
|
if (avtabIterP == None):
|
|
sys.exit("Failed to initialize avtab")
|
|
self.__GetTERules(self.__policydbP, avtabIterP, self.__Rules)
|
|
self.__libsepolwrap.destroy_avtab(avtabIterP)
|
|
avtabIterP = self.__libsepolwrap.init_cond_avtab(self.__policydbP)
|
|
if (avtabIterP == None):
|
|
sys.exit("Failed to initialize conditional avtab")
|
|
self.__GetTERules(self.__policydbP, avtabIterP, self.__Rules)
|
|
self.__libsepolwrap.destroy_avtab(avtabIterP)
|
|
|
|
def __InitExpandedTERules(self):
|
|
avtabIterP = self.__libsepolwrap.init_expanded_avtab(self.__policydbP)
|
|
if (avtabIterP == None):
|
|
sys.exit("Failed to initialize avtab")
|
|
self.__GetTERules(self.__policydbP, avtabIterP, self.__ExpandedRules)
|
|
self.__libsepolwrap.destroy_expanded_avtab(avtabIterP)
|
|
avtabIterP = self.__libsepolwrap.init_expanded_cond_avtab(self.__policydbP)
|
|
if (avtabIterP == None):
|
|
sys.exit("Failed to initialize conditional avtab")
|
|
self.__GetTERules(self.__policydbP, avtabIterP, self.__ExpandedRules)
|
|
self.__libsepolwrap.destroy_expanded_avtab(avtabIterP)
|
|
|
|
# load ctypes-ified libsepol wrapper
|
|
def __InitLibsepolwrap(self, LibPath):
|
|
lib = CDLL(LibPath)
|
|
|
|
# int get_allow_rule(char *out, size_t len, void *policydbp, void *avtab_iterp);
|
|
lib.get_allow_rule.restype = c_int
|
|
lib.get_allow_rule.argtypes = [c_char_p, c_size_t, c_void_p, c_void_p];
|
|
# void *load_policy(const char *policy_path);
|
|
lib.load_policy.restype = c_void_p
|
|
lib.load_policy.argtypes = [c_char_p]
|
|
# void destroy_policy(void *policydbp);
|
|
lib.destroy_policy.argtypes = [c_void_p]
|
|
# void *init_expanded_avtab(void *policydbp);
|
|
lib.init_expanded_avtab.restype = c_void_p
|
|
lib.init_expanded_avtab.argtypes = [c_void_p]
|
|
# void *init_expanded_cond_avtab(void *policydbp);
|
|
lib.init_expanded_cond_avtab.restype = c_void_p
|
|
lib.init_expanded_cond_avtab.argtypes = [c_void_p]
|
|
# void destroy_expanded_avtab(void *avtab_iterp);
|
|
lib.destroy_expanded_avtab.argtypes = [c_void_p]
|
|
# void *init_avtab(void *policydbp);
|
|
lib.init_avtab.restype = c_void_p
|
|
lib.init_avtab.argtypes = [c_void_p]
|
|
# void *init_cond_avtab(void *policydbp);
|
|
lib.init_cond_avtab.restype = c_void_p
|
|
lib.init_cond_avtab.argtypes = [c_void_p]
|
|
# void destroy_avtab(void *avtab_iterp);
|
|
lib.destroy_avtab.argtypes = [c_void_p]
|
|
# int get_type(char *out, size_t max_size, void *policydbp, void *type_iterp);
|
|
lib.get_type.restype = c_int
|
|
lib.get_type.argtypes = [c_char_p, c_size_t, c_void_p, c_void_p]
|
|
# void *init_type_iter(void *policydbp, const char *type, bool is_attr);
|
|
lib.init_type_iter.restype = c_void_p
|
|
lib.init_type_iter.argtypes = [c_void_p, c_char_p, c_bool]
|
|
# void destroy_type_iter(void *type_iterp);
|
|
lib.destroy_type_iter.argtypes = [c_void_p]
|
|
# void *init_genfs_iter(void *policydbp)
|
|
lib.init_genfs_iter.restype = c_void_p
|
|
lib.init_genfs_iter.argtypes = [c_void_p]
|
|
# int get_genfs(char *out, size_t max_size, void *genfs_iterp);
|
|
lib.get_genfs.restype = c_int
|
|
lib.get_genfs.argtypes = [c_char_p, c_size_t, c_void_p, c_void_p]
|
|
# void destroy_genfs_iter(void *genfs_iterp)
|
|
lib.destroy_genfs_iter.argtypes = [c_void_p]
|
|
|
|
self.__libsepolwrap = lib
|
|
|
|
def __GenfsDictAdd(self, Dict, buf):
|
|
fs, path, context = buf.split(" ")
|
|
Type = context.split(":")[2]
|
|
if not fs in Dict:
|
|
Dict[fs] = {Type}
|
|
else:
|
|
Dict[fs].add(Type)
|
|
|
|
def __InitGenfsCon(self):
|
|
self.__GenfsDict = {}
|
|
GenfsIterP = self.__libsepolwrap.init_genfs_iter(self.__policydbP)
|
|
if (GenfsIterP == None):
|
|
sys.exit("Failed to retreive genfs entries")
|
|
buf = create_string_buffer(self.__BUFSIZE)
|
|
while True:
|
|
ret = self.__libsepolwrap.get_genfs(buf, self.__BUFSIZE,
|
|
self.__policydbP, GenfsIterP)
|
|
if ret == 0:
|
|
self.__GenfsDictAdd(self.__GenfsDict, buf.value)
|
|
continue
|
|
if ret == 1:
|
|
self.__GenfsDictAdd(self.__GenfsDict, buf.value)
|
|
break;
|
|
# We should never get here.
|
|
sys.exit("Failed to get genfs entries")
|
|
self.__libsepolwrap.destroy_genfs_iter(GenfsIterP)
|
|
|
|
# load file_contexts
|
|
def __InitFC(self, FcPaths):
|
|
if FcPaths is None:
|
|
return
|
|
fc = []
|
|
for path in FcPaths:
|
|
if not os.path.exists(path):
|
|
sys.exit("file_contexts file " + path + " does not exist.")
|
|
fd = open(path, "r")
|
|
fc += fd.readlines()
|
|
fd.close()
|
|
self.__FcDict = {}
|
|
for i in fc:
|
|
rec = i.split()
|
|
try:
|
|
t = rec[-1].split(":")[2]
|
|
if t in self.__FcDict:
|
|
self.__FcDict[t].append(rec[0])
|
|
else:
|
|
self.__FcDict[t] = [rec[0]]
|
|
except:
|
|
pass
|
|
self.__FcSorted = fc_sort.FcSort(FcPaths)
|
|
|
|
# load policy
|
|
def __InitPolicy(self, PolicyPath):
|
|
cPolicyPath = create_string_buffer(PolicyPath)
|
|
self.__policydbP = self.__libsepolwrap.load_policy(cPolicyPath)
|
|
if (self.__policydbP is None):
|
|
sys.exit("Failed to load policy")
|
|
|
|
def __init__(self, PolicyPath, FcPaths, LibPath):
|
|
self.__InitLibsepolwrap(LibPath)
|
|
self.__InitFC(FcPaths)
|
|
self.__InitPolicy(PolicyPath)
|
|
self.__InitGenfsCon()
|
|
|
|
def __del__(self):
|
|
if self.__policydbP is not None:
|
|
self.__libsepolwrap.destroy_policy(self.__policydbP)
|