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