selinux-refpolicy/support/genhomedircon.py

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#!/usr/bin/env python3
# Copyright (C) 2004 Tresys Technology, LLC
# see file 'COPYING' for use and warranty information
#
# genhomedircon - this script is used to generate file context
# configuration entries for user home directories based on their
# default roles and is run when building the policy. Specifically, we
# replace HOME_ROOT, HOME_DIR, and ROLE macros in .fc files with
# generic and user-specific values.
#
# Based off original script by Dan Walsh, <dwalsh@redhat.com>
#
# ASSUMPTIONS:
#
# The file CONTEXTDIR/files/homedir_template exists. This file is used to
# set up the home directory context for each real user.
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#
# If a user has more than one role in CONTEXTDIR/local.users, genhomedircon uses
# the first role in the list.
#
# If a user is not listed in CONTEXTDIR/local.users, he will default to user_u, role user
#
# "Real" users (as opposed to system users) are those whose UID is greater than
# or equal STARTING_UID (usually 500) and whose login is not a member of
# EXCLUDE_LOGINS. Users who are explicitly defined in CONTEXTDIR/local.users
# are always "real" (including root, in the default configuration).
#
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#
# Old ASSUMPTIONS:
#
# If a user has more than one role in FILECONTEXTDIR/users, genhomedircon uses
# the first role in the list.
#
# If a user is not listed in FILECONTEXTDIR/users, genhomedircon assumes that
# the user's home dir will be found in one of the HOME_ROOTs.
#
# "Real" users (as opposed to system users) are those whose UID is greater than
# or equal STARTING_UID (usually 500) and whose login is not a member of
# EXCLUDE_LOGINS. Users who are explicitly defined in FILECONTEXTDIR/users
# are always "real" (including root, in the default configuration).
#
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import sys, os, pwd, getopt, re
EXCLUDE_LOGINS=["/sbin/nologin", "/bin/false"]
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# Python 2/3 wrapper
def getstatusoutput_wrapper(cmd):
if sys.version_info.major is 2:
import commands
return commands.getstatusoutput(cmd)
elif sys.version_info.major is 3:
import subprocess
return subprocess.getstatusoutput(cmd)
else:
print("Unsupported Python major version: " + sys.version_info.major)
exit(1)
def getStartingUID():
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starting_uid = 99999
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rc=getstatusoutput_wrapper("grep -h '^UID_MIN' /etc/login.defs")
if rc[0] == 0:
uid_min = re.sub("^UID_MIN[^0-9]*", "", rc[1])
#stip any comment from the end of the line
uid_min = uid_min.split("#")[0]
uid_min = uid_min.strip()
if int(uid_min) < starting_uid:
starting_uid = int(uid_min)
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rc=getstatusoutput_wrapper("grep -h '^LU_UIDNUMBER' /etc/libuser.conf")
if rc[0] == 0:
lu_uidnumber = re.sub("^LU_UIDNUMBER[^0-9]*", "", rc[1])
#stip any comment from the end of the line
lu_uidnumber = re.sub("[ \t].*", "", lu_uidnumber)
lu_uidnumber = lu_uidnumber.split("#")[0]
lu_uidnumber = lu_uidnumber.strip()
if int(lu_uidnumber) < starting_uid:
starting_uid = int(lu_uidnumber)
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if starting_uid == 99999:
starting_uid = 500
return starting_uid
#############################################################################
#
# This section is just for backwards compatability
#
#############################################################################
def getPrefixes():
ulist = pwd.getpwall()
STARTING_UID=getStartingUID()
prefixes = {}
for u in ulist:
if u[2] >= STARTING_UID and \
not u[6] in EXCLUDE_LOGINS and \
u[5] != "/" and \
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u[5].count("/") > 1:
prefix = u[5][:u[5].rfind("/")]
if not prefix in prefixes:
prefixes[prefix] = ""
return prefixes
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def getUsers(filecontextdir):
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rc = getstatusoutput_wrapper("grep ^user %s/users" % filecontextdir)
udict = {}
if rc[0] == 0:
ulist = rc[1].strip().split("\n")
for u in ulist:
user = u.split()
try:
if user[1] == "user_u" or user[1] == "system_u":
continue
# !!! chooses first role in the list to use in the file context !!!
role = user[3]
if role == "{":
role = user[4]
role = role.split("_r")[0]
home = pwd.getpwnam(user[1])[5]
if home == "/":
continue
prefs = {}
prefs["role"] = role
prefs["home"] = home
udict[user[1]] = prefs
except KeyError:
sys.stderr.write("The user \"%s\" is not present in the passwd file, skipping...\n" % user[1])
return udict
def update(filecontext, user, prefs):
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rc=getstatusoutput_wrapper("grep -h '^HOME_DIR' %s | grep -v vmware | sed -e 's|HOME_DIR|%s|' -e 's/ROLE/%s/' -e 's/system_u/%s/'" % (filecontext, prefs["home"], prefs["role"], user))
if rc[0] == 0:
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print(rc[1])
else:
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errorExit("grep/sed error " + rc[1])
return rc
def oldgenhomedircon(filecontextdir, filecontext):
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sys.stderr.flush()
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if os.path.isdir(filecontextdir) == 0:
sys.stderr.write("New usage is the following\n")
usage()
#We are going to define home directory used by libuser and show-utils as a home directory root
prefixes = {}
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rc=getstatusoutput_wrapper("grep -h '^HOME' /etc/default/useradd")
if rc[0] == 0:
homedir = rc[1].split("=")[1]
homedir = homedir.split("#")[0]
homedir = homedir.strip()
if not homedir in prefixes:
prefixes[homedir] = ""
else:
#rc[0] == 256 means the file was there, we read it, but the grep didn't match
if rc[0] != 256:
sys.stderr.write("%s\n" % rc[1])
sys.stderr.write("You do not have access to /etc/default/useradd HOME=\n")
sys.stderr.flush()
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rc=getstatusoutput_wrapper("grep -h '^LU_HOMEDIRECTORY' /etc/libuser.conf")
if rc[0] == 0:
homedir = rc[1].split("=")[1]
homedir = homedir.split("#")[0]
homedir = homedir.strip()
homedir = re.sub(r"[^/a-zA-Z0-9].*$", "", homedir)
if not homedir in prefixes:
prefixes[homedir] = ""
#the idea is that we need to find all of the home_root_t directories we do this by just accepting
#any default home directory defined by either /etc/libuser.conf or /etc/default/useradd
#we then get the potential home directory roots from /etc/passwd or nis or wherever and look at
#the defined homedir for all users with UID > STARTING_UID. This list of possible root homedirs
#is then checked to see if it has an explicite context defined in the file_contexts. Explicit
#is any regex that would match it which does not end with .*$ or .+$ since those are general
#recursive matches. We then take any regex which ends with [pattern](/.*)?$ and just check against
#[pattern]
potential_prefixes = getPrefixes()
prefix_regex = {}
#this works by grepping the file_contexts for
# 1. ^/ makes sure this is not a comment
# 2. prints only the regex in the first column first cut on \t then on space
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rc=getstatusoutput_wrapper("grep \"^/\" %s | cut -f 1 | cut -f 1 -d \" \" " % (sys.argv[2]) )
if rc[0] == 0:
prefix_regex = rc[1].split("\n")
else:
sys.stderr.write("%s\n" % rc[1])
sys.stderr.write("You do not have access to grep/cut/the file contexts\n")
sys.stderr.flush()
for potential in potential_prefixes.keys():
addme = 1
for regex in prefix_regex:
#match a trailing (/*)? which is actually a bug in rpc_pipefs
regex = re.sub(r"\(/\*\)\?$", "", regex)
#match a trailing .+
regex = re.sub(r"\.+$", "", regex)
#match a trailing .*
regex = re.sub(r"\.\*$", "", regex)
#strip a (/.*)? which matches anything trailing to a /*$ which matches trailing /'s
regex = re.sub(r"\(\/\.\*\)\?", "", regex)
regex = regex + "/*$"
if re.search(regex, potential, 0):
addme = 0
if addme == 1:
if not potential in prefixes:
prefixes[potential] = ""
if prefixes.__eq__({}):
sys.stderr.write("LU_HOMEDIRECTORY not set in /etc/libuser.conf\n")
sys.stderr.write("HOME= not set in /etc/default/useradd\n")
sys.stderr.write("And no users with a reasonable homedir found in passwd/nis/ldap/etc...\n")
sys.stderr.write("Assuming /home is the root of home directories\n")
sys.stderr.flush()
prefixes["/home"] = ""
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# There may be a more elegant sed script to expand a macro to multiple lines, but this works
sed_root = "h; s|^HOME_ROOT|%s|" % (prefixes.keys() + "|; p; g; s|^HOME_ROOT|")
sed_dir = "h; s|^HOME_DIR|%s/[^/]+|; s|ROLE_|user_|" % (prefixes.keys() + "/[^/]+|; s|ROLE_|user_|; p; g; s|^HOME_DIR|")
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# Fill in HOME_ROOT, HOME_DIR, and ROLE for users not explicitly defined in /etc/security/selinux/src/policy/users
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rc=getstatusoutput_wrapper("sed -e \"/^HOME_ROOT/{%s}\" -e \"/^HOME_DIR/{%s}\" %s" % (sed_root, sed_dir, filecontext))
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if rc[0] == 0:
print(rc[1])
else:
errorExit("sed error " + rc[1])
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users = getUsers(filecontextdir)
print("\n#\n# User-specific file contexts\n#\n")
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# Fill in HOME and ROLE for users that are defined
for u in users.keys():
update(filecontext, u, users[u])
#############################################################################
#
# End of backwards compatability section
#
#############################################################################
def getDefaultHomeDir():
ret = []
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rc=getstatusoutput_wrapper("grep -h '^HOME' /etc/default/useradd")
if rc[0] == 0:
homedir = rc[1].split("=")[1]
homedir = homedir.split("#")[0]
homedir = homedir.strip()
if not homedir in ret:
ret.append(homedir)
else:
#rc[0] == 256 means the file was there, we read it, but the grep didn't match
if rc[0] != 256:
sys.stderr.write("%s\n" % rc[1])
sys.stderr.write("You do not have access to /etc/default/useradd HOME=\n")
sys.stderr.flush()
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rc=getstatusoutput_wrapper("grep -h '^LU_HOMEDIRECTORY' /etc/libuser.conf")
if rc[0] == 0:
homedir = rc[1].split("=")[1]
homedir = homedir.split("#")[0]
homedir = homedir.strip()
if not homedir in ret:
ret.append(homedir)
else:
#rc[0] == 256 means the file was there, we read it, but the grep didn't match
if rc[0] != 256:
sys.stderr.write("%s\n" % rc[1])
sys.stderr.write("You do not have access to /etc/libuser.conf LU_HOMEDIRECTORY=\n")
sys.stderr.flush()
if ret == []:
ret.append("/home")
return ret
def getSELinuxType(directory):
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rc=getstatusoutput_wrapper("grep ^SELINUXTYPE= %s/config" % directory)
if rc[0]==0:
return rc[1].split("=")[-1].strip()
return "targeted"
def usage(error = ""):
if error != "":
sys.stderr.write("%s\n" % error)
sys.stderr.write("Usage: %s [ -d selinuxdir ] [-n | --nopasswd] [-t selinuxtype ]\n" % sys.argv[0])
sys.stderr.flush()
sys.exit(1)
def warning(warning = ""):
sys.stderr.write("%s\n" % warning)
sys.stderr.flush()
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def errorExit(error):
sys.stderr.write("%s exiting for: " % sys.argv[0])
sys.stderr.write("%s\n" % error)
sys.stderr.flush()
sys.exit(1)
class selinuxConfig:
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def __init__(self, selinuxdir="/etc/selinux", setype="targeted", usepwd=1):
self.setype=setype
self.selinuxdir=selinuxdir +"/"
self.contextdir="/contexts"
self.filecontextdir=self.contextdir+"/files"
self.usepwd=usepwd
def getFileContextDir(self):
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return self.selinuxdir+self.setype+self.filecontextdir
def getFileContextFile(self):
return self.getFileContextDir()+"/file_contexts"
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def getContextDir(self):
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return self.selinuxdir+self.setype+self.contextdir
def getHomeDirTemplate(self):
return self.getFileContextDir()+"/homedir_template"
def getHomeRootContext(self, homedir):
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rc=getstatusoutput_wrapper("grep HOME_ROOT %s | sed -e \"s|^HOME_ROOT|%s|\"" % ( self.getHomeDirTemplate(), homedir))
if rc[0] == 0:
return rc[1]+"\n"
else:
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errorExit("sed error " + rc[1])
def getUsersFile(self):
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return self.selinuxdir+self.setype+"/users/local.users"
def getSystemUsersFile(self):
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return self.selinuxdir+self.setype+"/users/system.users"
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def heading(self):
ret = "\n#\n#\n# User-specific file contexts, generated via %s\n" % sys.argv[0]
ret += "# edit %s to change file_context\n#\n#\n" % self.getUsersFile()
return ret
def getUsers(self):
users=""
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rc = getstatusoutput_wrapper('grep "^user" %s' % self.getSystemUsersFile())
if rc[0] == 0:
users+=rc[1]+"\n"
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rc = getstatusoutput_wrapper("grep ^user %s" % self.getUsersFile())
if rc[0] == 0:
users+=rc[1]
udict = {}
prefs = {}
if users != "":
ulist = users.split("\n")
for u in ulist:
user = u.split()
try:
if len(user)==0 or user[1] == "user_u" or user[1] == "system_u":
continue
# !!! chooses first role in the list to use in the file context !!!
role = user[3]
if role == "{":
role = user[4]
role = role.split("_r")[0]
home = pwd.getpwnam(user[1])[5]
if home == "/":
continue
prefs = {}
prefs["role"] = role
prefs["home"] = home
udict[user[1]] = prefs
except KeyError:
sys.stderr.write("The user \"%s\" is not present in the passwd file, skipping...\n" % user[1])
return udict
def getHomeDirContext(self, user, home, role):
ret="\n\n#\n# Context for user %s\n#\n\n" % user
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rc=getstatusoutput_wrapper("grep '^HOME_DIR' %s | sed -e 's|HOME_DIR|%s|' -e 's/ROLE/%s/' -e 's/system_u/%s/'" % (self.getHomeDirTemplate(), home, role, user))
return ret + rc[1] + "\n"
def genHomeDirContext(self):
users = self.getUsers()
ret=""
# Fill in HOME and ROLE for users that are defined
for u in users.keys():
ret += self.getHomeDirContext (u, users[u]["home"], users[u]["role"])
return ret+"\n"
def checkExists(self, home):
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if getstatusoutput_wrapper("grep -E '^%s[^[:alnum:]_-]' %s" % (home, self.getFileContextFile()))[0] == 0:
return 0
#this works by grepping the file_contexts for
# 1. ^/ makes sure this is not a comment
# 2. prints only the regex in the first column first cut on \t then on space
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rc=getstatusoutput_wrapper("grep \"^/\" %s | cut -f 1 | cut -f 1 -d \" \" " % self.getFileContextFile() )
if rc[0] == 0:
prefix_regex = rc[1].split("\n")
else:
sys.stderr.write("%s\n" % rc[1])
sys.stderr.write("You do not have access to grep/cut/the file contexts\n")
sys.stderr.flush()
exists=1
for regex in prefix_regex:
#match a trailing (/*)? which is actually a bug in rpc_pipefs
regex = re.sub(r"\(/\*\)\?$", "", regex)
#match a trailing .+
regex = re.sub(r"\.+$", "", regex)
#match a trailing .*
regex = re.sub(r"\.\*$", "", regex)
#strip a (/.*)? which matches anything trailing to a /*$ which matches trailing /'s
regex = re.sub(r"\(\/\.\*\)\?", "", regex)
regex = regex + "/*$"
if re.search(regex, home, 0):
exists = 0
break
if exists == 1:
return 1
else:
return 0
def getHomeDirs(self):
homedirs = []
homedirs = homedirs + getDefaultHomeDir()
starting_uid=getStartingUID()
if self.usepwd==0:
return homedirs
ulist = pwd.getpwall()
for u in ulist:
if u[2] >= starting_uid and \
not u[6] in EXCLUDE_LOGINS and \
u[5] != "/" and \
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u[5].count("/") > 1:
homedir = u[5][:u[5].rfind("/")]
if not homedir in homedirs:
if self.checkExists(homedir)==0:
warning("%s is already defined in %s,\n%s will not create a new context." % (homedir, self.getFileContextFile(), sys.argv[0]))
else:
homedirs.append(homedir)
homedirs.sort()
return homedirs
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def genoutput(self):
ret= self.heading()
for h in self.getHomeDirs():
ret += self.getHomeDirContext ("user_u" , h+'/[^/]*', "user")
ret += self.getHomeRootContext(h)
ret += self.genHomeDirContext()
return ret
def printout(self):
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print(self.genoutput())
def write(self):
try:
fd = open(self.getFileContextDir()+"/file_contexts.homedirs", "w")
fd.write(self.genoutput())
fd.close()
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except IOError as error:
sys.stderr.write("%s: %s\n" % ( sys.argv[0], error ))
#
# This script will generate home dir file context
# based off the homedir_template file, entries in the password file, and
#
try:
usepwd=1
directory="/etc/selinux"
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setype=None
gopts, cmds = getopt.getopt(sys.argv[1:], 'nd:t:', ['help',
'type=',
'nopasswd',
'dir='])
for o,a in gopts:
if o == '--type' or o == "-t":
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setype=a
if o == '--nopasswd' or o == "-n":
usepwd=0
if o == '--dir' or o == "-d":
directory=a
if o == '--help':
usage()
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if setype is None:
setype=getSELinuxType(directory)
if len(cmds) == 2:
oldgenhomedircon(cmds[0], cmds[1])
sys.exit(0)
if len(cmds) != 0:
usage()
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selconf=selinuxConfig(directory, setype, usepwd)
selconf.write()
except Exception as error:
errorExit(error)