210 lines
7.0 KiB
Python
Executable File
210 lines
7.0 KiB
Python
Executable File
#!/usr/bin/python
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import sys
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import os
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import os.path
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import subprocess
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import xen.lowlevel.xl
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import qubes.guihelpers
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from optparse import OptionParser
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import fcntl
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POLICY_FILE_DIR="/etc/qubes-rpc/policy"
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# XXX: Backward compatibility, to be removed soon
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DEPRECATED_POLICY_FILE_DIR="/etc/qubes_rpc/policy"
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QREXEC_CLIENT="/usr/lib/qubes/qrexec-client"
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class UserChoice:
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ALLOW=0
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DENY=1
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ALWAYS_ALLOW=2
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def line_to_dict(line):
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tokens=line.split()
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if len(tokens) < 3:
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return None
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if tokens[0][0] == '#':
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return None
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dict={}
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dict['source']=tokens[0]
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dict['dest']=tokens[1]
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dict['full-action']=tokens[2]
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action_list=tokens[2].split(',')
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dict['action']=action_list.pop(0)
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for iter in action_list:
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paramval=iter.split("=")
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dict["action."+paramval[0]]=paramval[1]
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return dict
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def read_policy_file(exec_index):
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policy_file=POLICY_FILE_DIR+"/"+exec_index
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if not os.path.isfile(policy_file):
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policy_file=DEPRECATED_POLICY_FILE_DIR+"/"+exec_index
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if not os.path.isfile(policy_file):
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return None
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print >>sys.stderr, "RPC service '%s' uses deprecated policy location, please move to %s" % (exec_index, POLICY_FILE_DIR)
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policy_list=list()
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f = open(policy_file)
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fcntl.flock(f, fcntl.LOCK_SH)
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for iter in f.readlines():
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dict = line_to_dict(iter)
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if dict is not None:
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policy_list.append(dict)
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f.close()
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return policy_list
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def is_match(item, config_term):
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return (item is not "dom0" and config_term == "$anyvm") or item == config_term
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def get_default_policy():
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dict={}
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dict["action"]="deny"
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return dict
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def find_policy(policy, domain, target):
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for iter in policy:
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if not is_match(domain, iter["source"]):
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continue
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if not is_match(target, iter["dest"]):
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continue
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return iter
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return get_default_policy()
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def is_domain_running(target):
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xl_ctx = xen.lowlevel.xl.ctx()
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domains = xl_ctx.list_domains()
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for dominfo in domains:
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domname = xl_ctx.domid_to_name(dominfo.domid)
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if domname == target:
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return True
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return False
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def validate_target(target):
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# special targets
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if target in ['$dispvm', 'dom0']:
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return True
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from qubes.qubes import QubesVmCollection
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qc = QubesVmCollection()
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qc.lock_db_for_reading()
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qc.load()
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qc.unlock_db()
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return qc.get_vm_by_name(target) is not None
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def spawn_target_if_necessary(target):
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if is_domain_running(target):
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return
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null=open("/dev/null", "r+")
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subprocess.call(["qvm-run", "-a", "-q", target, "true"], stdin=null, stdout=null)
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null.close()
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def do_execute(domain, target, user, exec_index, process_ident):
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if target == "dom0":
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cmd="/usr/lib/qubes/qubes-rpc-multiplexer "+exec_index + " " + domain
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elif target == "$dispvm":
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cmd = "/usr/lib/qubes/qfile-daemon-dvm " + exec_index + " " + domain + " " +user
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else:
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# see the previous commit why "qvm-run -a" is broken and dangerous
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# also, dangling "xl" would keep stderr open and may prevent closing connection
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spawn_target_if_necessary(target)
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cmd= QREXEC_CLIENT + " -d " + target + " '" + user
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cmd+=":QUBESRPC "+ exec_index + " " + domain + "'"
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os.execl(QREXEC_CLIENT, "qrexec-client", "-d", domain, "-l", cmd, "-c", process_ident)
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def confirm_execution(domain, target, exec_index):
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text = "Do you allow domain \"" +domain + "\" to execute " + exec_index
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text+= " operation on the domain \"" + target +"\"?<br>"
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text+= " \"Yes to All\" option will automatically allow this operation in the future."
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return qubes.guihelpers.ask(text, yestoall=True)
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def add_always_allow(domain, target, exec_index, options):
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policy_file=POLICY_FILE_DIR+"/"+exec_index
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if not os.path.isfile(policy_file):
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return None
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f = open(policy_file, 'r+')
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fcntl.flock(f, fcntl.LOCK_EX)
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lines = []
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for l in f.readlines():
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lines.append(l)
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lines.insert(0, "%s\t%s\tallow%s\n" % (domain, target, options))
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f.seek(0)
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f.write("".join(lines))
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f.close()
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def policy_editor(domain, target, exec_index):
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text = "No policy definition found for " + exec_index + " action. "
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text+= "Please create a policy file in Dom0 in " + POLICY_FILE_DIR + "/" + exec_index
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subprocess.call(["/usr/bin/zenity", "--info", "--text", text])
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def main():
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usage = "usage: %prog [options] <src-domain> <target-domain> <service> <process-ident>"
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parser = OptionParser (usage)
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parser.add_option ("--assume-yes-for-ask", action="store_true", dest="assume_yes_for_ask", default=False,
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help="Allow run of service without confirmation if policy say 'ask'")
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parser.add_option ("--just-evaluate", action="store_true", dest="just_evaluate", default=False,
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help="Do not run the service, only evaluate policy; retcode=0 means 'allow'")
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(options, args) = parser.parse_args ()
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domain=args[0]
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target=args[1]
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exec_index=args[2]
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process_ident=args[3]
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if not validate_target(target):
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print >> sys.stderr, "Rpc failed (unknown domain):", domain, target, exec_index
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text = "Domain '%s' doesn't exists (service %s called by domain %s)." % (
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target, exec_index, domain)
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subprocess.call(["/usr/bin/zenity", "--error", "--text", text])
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os.execl(QREXEC_CLIENT, "qrexec-client", "-d", domain, "-l", "/bin/false", "-c", process_ident)
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policy_list=read_policy_file(exec_index)
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if policy_list==None:
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policy_editor(domain, target, exec_index)
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policy_list=read_policy_file(exec_index)
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if policy_list==None:
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policy_list=list()
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policy_dict=find_policy(policy_list, domain, target)
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if policy_dict["action"] == "ask" and options.assume_yes_for_ask:
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policy_dict["action"] = "allow"
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if policy_dict["action"] == "ask":
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user_choice = confirm_execution(domain, target, exec_index)
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if user_choice == UserChoice.ALWAYS_ALLOW:
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add_always_allow(domain, target, exec_index, policy_dict["full-action"].lstrip('ask'))
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policy_dict["action"] = "allow"
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elif user_choice == UserChoice.ALLOW:
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policy_dict["action"] = "allow"
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else:
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policy_dict["action"] = "deny"
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if options.just_evaluate:
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if policy_dict["action"] == "allow":
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exit(0)
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else:
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exit(1)
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if policy_dict["action"] == "allow":
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if policy_dict.has_key("action.target"):
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target=policy_dict["action.target"]
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if policy_dict.has_key("action.user"):
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user=policy_dict["action.user"]
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else:
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user="DEFAULT"
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print >> sys.stderr, "Rpc allowed:", domain, target, exec_index
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do_execute(domain, target, user, exec_index, process_ident)
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print >> sys.stderr, "Rpc denied:", domain, target, exec_index
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os.execl(QREXEC_CLIENT, "qrexec-client", "-d", domain, "-l", "/bin/false", "-c", process_ident)
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main()
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