core-admin/qrexec/qrexec_policy

#!/usr/bin/python
import sys
import os
import os.path
import subprocess
 
POLICY_FILE_DIR="/etc/qubes_rpc/policy"
QREXEC_CLIENT="/usr/lib/qubes/qrexec_client"

def line_to_dict(line):
    tokens=line.split()
    if len(tokens) < 3:
        return None
    dict={}
    dict['source']=tokens[0]
    dict['dest']=tokens[1]
    
    action_list=tokens[2].split(',')
    dict['action']=action_list.pop(0)
    
    for iter in action_list:
        paramval=iter.split("=")
        dict["action."+paramval[0]]=paramval[1]
    
    return dict 


def read_policy_file(exec_index):
    policy_file=POLICY_FILE_DIR+"/"+exec_index
    if not os.path.isfile(policy_file):
        return None
    policy_list=list()
    f = open(policy_file)
    for iter in f.readlines():
        dict = line_to_dict(iter)
        if dict is not None:
            policy_list.append(dict)
    f.close()
    return policy_list

def is_match(item, config_term):
    return (item is not "dom0" and config_term == "anyvm") or item == config_term

def get_default_policy():
    dict={}
    dict["action"]="deny"
    return dict
    

def find_policy(policy, domain, target):
    for iter in policy:
        if not is_match(domain, iter["source"]):
            continue
        if not is_match(target, iter["dest"]):
            continue
        return iter
    return get_default_policy()
                
def do_execute(domain, target, user, exec_index, process_ident):
    if target == "dom0":
        cmd="/usr/lib/qubes/qubes_rpc_multiplexer "+exec_index + " " + domain
    elif target == "dispvm":
        cmd = "/usr/lib/qubes/qfile-daemon-dvm " + exec_index + " " + domain + " " +user
    else:
#fixme: qvm-run --pass_io is broken for non-running target domain
        cmd= "qvm-run -uroot -q --pass_io "+target + " -u" + user 
        cmd+=" '/usr/lib/qubes/qubes_rpc_multiplexer "+exec_index + " " + domain + "'"
    os.execl(QREXEC_CLIENT, "qrexec_client", "-d", domain, "-l", cmd, "-c", process_ident)

def confirm_execution(domain, target, exec_index):
    text = "Do you allow domain \"" +domain + "\" to execute " + exec_index
    text+= " operation on the domain \"" + target +"\"?" 
    retcode = subprocess.call(["/usr/bin/zenity", "--question", "--text", text])
    return retcode==0

def policy_editor(domain, target, exec_index):
    text = "Policy editor not yet implemented. Please add a line in the form \""
    text+= domain + " " + target + "action_to_take\""
    text+= " to /etc/qubes_rpc/policy/" + exec_index +" file in dom0, then close this info."
    subprocess.call(["/usr/bin/zenity", "--info", "--text", text]) 

def main():
    domain=sys.argv[1]
    target=sys.argv[2]
    exec_index=sys.argv[3]
    process_ident=sys.argv[4]
    
    policy_list=read_policy_file(exec_index)
    if policy_list==None:
        policy_editor(domain, target, exec_index)
        policy_list=read_policy_file(exec_index)
        if policy_list==None:
            policy_list=list()

    policy_dict=find_policy(policy_list, domain, target)
    
    if policy_dict["action"] == "ask":
        if confirm_execution(domain, target, exec_index):
            policy_dict["action"] = "allow"
        else:
            policy_dict["action"] = "deny"
    
    if policy_dict["action"] == "allow":
        if policy_dict.has_key("action.target"):
            target=policy_dict["action.target"]
        if policy_dict.has_key("action.user"):
            user=policy_dict["action.user"]
        else:
            user="user"
        do_execute(domain, target, user, exec_index, process_ident)

    print >> sys.stderr, "Rpc denied:", domain, target, exec_index    
    os.execl(QREXEC_CLIENT, "qrexec_client", "-d", domain, "-l", "/bin/false", "-c", process_ident)

main()