Helpviewer/Passwords/PasswordManager.py

# -*- coding: utf-8 -*-

# Copyright (c) 2009 - 2013 Detlev Offenbach <detlev@die-offenbachs.de>
#

"""
Module implementing the password manager.
"""

import os

from PyQt4.QtCore import pyqtSignal, QObject, QByteArray, QUrl, QCoreApplication
from PyQt4.QtGui import QProgressDialog, QApplication
from PyQt4.QtNetwork import QNetworkRequest
from PyQt4.QtWebKit import QWebSettings, QWebPage

from E5Gui import E5MessageBox

from Helpviewer.JavaScriptResources import parseForms_js

from Utilities.AutoSaver import AutoSaver
import Utilities
import Utilities.crypto
import Preferences


class LoginForm(object):
    """
    Class implementing a data structure for login forms.
    """
    def __init__(self):
        """
        Constructor
        """
        self.url = QUrl()
        self.name = ""
        self.hasAPassword = False
        self.elements = []      # list of tuples of element name and value
                                # (string, string)
        self.elementTypes = {}  # dict of element name as key and type as value
    
    def isValid(self):
        """
        Public method to test for validity.
        
        @return flag indicating a valid form (boolean)
        """
        return len(self.elements) > 0
    
    def load(self, data):
        """
        Public method to load the form data from a file.
        
        @param data list of strings to load data from (list of strings)
        @return flag indicating success (boolean)
        """
        self.url = QUrl(data[0])
        self.name = data[1]
        self.hasAPassword = data[2] == "True"
        for element in data[3:]:
            name, value = element.split(" = ", 1)
            self.elements.append((name, value))
    
    def save(self, f):
        """
        Public method to save the form data to a file.
        
        @param f file or file like object open for writing
        @return flag indicating success (booelan)
        """
        f.write("{0}\n".format(self.url.toString()))
        f.write("{0}\n".format(self.name))
        f.write("{0}\n".format(self.hasAPassword))
        for element in self.elements:
            f.write("{0} = {1}\n".format(element[0], element[1]))


class PasswordManager(QObject):
    """
    Class implementing the password manager.
    
    @signal changed() emitted to indicate a change
    """
    changed = pyqtSignal()
    
    SEPARATOR = "===================="
    FORMS = "=====FORMS====="
    NEVER = "=====NEVER====="
    
    def __init__(self, parent=None):
        """
        Constructor
        
        @param parent reference to the parent object (QObject)
        """
        super().__init__(parent)
        
        self.__logins = {}
        self.__loginForms = {}
        self.__never = []
        self.__loaded = False
        self.__saveTimer = AutoSaver(self, self.save)
        
        self.changed.connect(self.__saveTimer.changeOccurred)
    
    def clear(self):
        """
        Public slot to clear the saved passwords.
        """
        if not self.__loaded:
            self.__load()
        
        self.__logins = {}
        self.__loginForms = {}
        self.__never = []
        self.__saveTimer.changeOccurred()
        self.__saveTimer.saveIfNeccessary()
        
        self.changed.emit()
    
    def getLogin(self, url, realm):
        """
        Public method to get the login credentials.
        
        @param url URL to get the credentials for (QUrl)
        @param realm realm to get the credentials for (string)
        @return tuple containing the user name (string) and password (string)
        """
        if not self.__loaded:
            self.__load()
        
        key = self.__createKey(url, realm)
        try:
            return self.__logins[key][0], Utilities.crypto.pwConvert(
                self.__logins[key][1], encode=False)
        except KeyError:
            return "", ""
    
    def setLogin(self, url, realm, username, password):
        """
        Public method to set the login credentials.
        
        @param url URL to set the credentials for (QUrl)
        @param realm realm to set the credentials for (string)
        @param username username for the login (string)
        @param password password for the login (string)
        """
        if not self.__loaded:
            self.__load()
        
        key = self.__createKey(url, realm)
        self.__logins[key] = (username, Utilities.crypto.pwConvert(password, encode=True))
        self.changed.emit()
    
    def __createKey(self, url, realm):
        """
        Private method to create the key string for the login credentials.
        
        @param url URL to get the credentials for (QUrl)
        @param realm realm to get the credentials for (string)
        @return key string (string)
        """
        if realm:
            key = "{0}://{1} ({2})".format(url.scheme(), url.authority(), realm)
        else:
            key = "{0}://{1}".format(url.scheme(), url.authority())
        return key
    
    def save(self):
        """
        Public slot to save the login entries to disk.
        """
        if not self.__loaded:
            return
        
        loginFile = os.path.join(Utilities.getConfigDir(), "browser", "logins")
        try:
            f = open(loginFile, "w", encoding="utf-8")
            for key, login in list(self.__logins.items()):
                f.write("{0}\n".format(key))
                f.write("{0}\n".format(login[0]))
                f.write("{0}\n".format(login[1]))
                f.write("{0}\n".format(self.SEPARATOR))
            if self.__loginForms:
                f.write("{0}\n".format(self.FORMS))
                for key, form in list(self.__loginForms.items()):
                    f.write("{0}\n".format(key))
                    form.save(f)
                    f.write("{0}\n".format(self.SEPARATOR))
            if self.__never:
                f.write("{0}\n".format(self.NEVER))
                for key in self.__never:
                    f.write("{0}\n".format(key))
            f.close()
        except IOError as err:
            E5MessageBox.critical(None,
                self.trUtf8("Saving login data"),
                self.trUtf8("""<p>Login data could not be saved to <b>{0}</b></p>"""
                            """<p>Reason: {1}</p>""").format(loginFile, str(err)))
            return
    
    def __load(self):
        """
        Private method to load the saved login credentials.
        """
        loginFile = os.path.join(Utilities.getConfigDir(), "browser", "logins")
        if os.path.exists(loginFile):
            try:
                f = open(loginFile, "r", encoding="utf-8")
                lines = f.read()
                f.close()
            except IOError as err:
                E5MessageBox.critical(None,
                    self.trUtf8("Loading login data"),
                    self.trUtf8("""<p>Login data could not be loaded """
                                """from <b>{0}</b></p>"""
                                """<p>Reason: {1}</p>""")\
                        .format(loginFile, str(err)))
                return
            
            data = []
            section = 0     # 0 = login data, 1 = forms data, 2 = never store info
            for line in lines.splitlines():
                if line == self.FORMS:
                    section = 1
                    continue
                elif line == self.NEVER:
                    section = 2
                    continue
                
                if section == 0:
                    if line != self.SEPARATOR:
                        data.append(line)
                    else:
                        if len(data) != 3:
                            E5MessageBox.critical(None,
                                self.trUtf8("Loading login data"),
                                self.trUtf8("""<p>Login data could not be loaded """
                                            """from <b>{0}</b></p>"""
                                            """<p>Reason: Wrong input format</p>""")\
                                    .format(loginFile))
                            return
                        self.__logins[data[0]] = (data[1], data[2])
                        data = []
                
                elif section == 1:
                    if line != self.SEPARATOR:
                        data.append(line)
                    else:
                        key = data[0]
                        form = LoginForm()
                        form.load(data[1:])
                        self.__loginForms[key] = form
                        data = []
                
                elif section == 2:
                    self.__never.append(line)
        
        self.__loaded = True
    
    def close(self):
        """
        Public method to close the passwords manager.
        """
        self.__saveTimer.saveIfNeccessary()
    
    def removePassword(self, site):
        """
        Public method to remove a password entry.
        
        @param site web site name (string)
        """
        if site in self.__logins:
            del self.__logins[site]
            if site in self.__loginForms:
                del self.__loginForms[site]
            self.changed.emit()
    
    def allSiteNames(self):
        """
        Public method to get a list of all site names.
        
        @return sorted list of all site names (list of strings)
        """
        if not self.__loaded:
            self.__load()
        
        return sorted(self.__logins.keys())
    
    def sitesCount(self):
        """
        Public method to get the number of available sites.
        
        @return number of sites (integer)
        """
        if not self.__loaded:
            self.__load()
        
        return len(self.__logins)
    
    def siteInfo(self, site):
        """
        Public method to get a reference to the named site.
        
        @param site web site name (string)
        @return tuple containing the user name (string) and password (string)
        """
        if not self.__loaded:
            self.__load()
        
        if site not in self.__logins:
            return None
        
        return self.__logins[site][0], Utilities.crypto.pwConvert(
            self.__logins[site][1], encode=False)
    
    def post(self, request, data):
        """
        Public method to check, if the data to be sent contains login data.
        
        @param request reference to the network request (QNetworkRequest)
        @param data data to be sent (QByteArray)
        """
        # shall passwords be saved?
        if not Preferences.getUser("SavePasswords"):
            return
        
        # observe privacy
        if QWebSettings.globalSettings().testAttribute(
                QWebSettings.PrivateBrowsingEnabled):
            return
        
        if not self.__loaded:
            self.__load()
        
        # determine the url
        refererHeader = request.rawHeader("Referer")
        if refererHeader.isEmpty():
            return
        url = QUrl.fromEncoded(refererHeader)
        url = self.__stripUrl(url)
        
        # check that url isn't in __never
        if url.toString() in self.__never:
            return
        
        # check the request type
        navType = request.attribute(QNetworkRequest.User + 101)
        if navType is None:
            return
        if navType != QWebPage.NavigationTypeFormSubmitted:
            return
        
        # determine the QWebPage
        webPage = request.attribute(QNetworkRequest.User + 100)
        if  webPage is None:
            return
        
        # determine the requests content type
        contentTypeHeader = request.rawHeader("Content-Type")
        if contentTypeHeader.isEmpty():
            return
        multipart = contentTypeHeader.startsWith("multipart/form-data")
        if multipart:
            boundary = contentTypeHeader.split(" ")[1].split("=")[1]
        else:
            boundary = None
        
        # find the matching form on the web page
        form = self.__findForm(webPage, data, boundary=boundary)
        if not form.isValid():
            return
        form.url = QUrl(url)
        
        # check, if the form has a password
        if not form.hasAPassword:
            return
        
        # prompt, if the form has never be seen
        key = self.__createKey(url, "")
        if key not in self.__loginForms:
            mb = E5MessageBox.E5MessageBox(E5MessageBox.Question,
                self.trUtf8("Save password"),
                self.trUtf8(
                    """<b>Would you like to save this password?</b><br/>"""
                    """To review passwords you have saved and remove them, """
                    """use the password management dialog of the Settings menu."""),
                modal=True)
            neverButton = mb.addButton(
                self.trUtf8("Never for this site"), E5MessageBox.DestructiveRole)
            noButton = mb.addButton(self.trUtf8("Not now"), E5MessageBox.RejectRole)
            mb.addButton(E5MessageBox.Yes)
            mb.exec_()
            if mb.clickedButton() == neverButton:
                self.__never.append(url.toString())
                return
            elif mb.clickedButton() == noButton:
                return
        
        # extract user name and password
        user = ""
        password = ""
        for index in range(len(form.elements)):
            element = form.elements[index]
            type_ = form.elementTypes[element[0]]
            if user == "" and \
               type_ == "text":
                user = element[1]
            elif password == "" and \
                 type_ == "password":
                password = element[1]
                form.elements[index] = (element[0], "--PASSWORD--")
        if user and password:
            self.__logins[key] = (user, Utilities.crypto.pwConvert(password, encode=True))
            self.__loginForms[key] = form
            self.changed.emit()
    
    def __stripUrl(self, url):
        """
        Private method to strip off all unneeded parts of a URL.
        
        @param url URL to be stripped (QUrl)
        @return stripped URL (QUrl)
        """
        cleanUrl = QUrl(url)
        cleanUrl.setQueryItems([])
        cleanUrl.setFragment("")
        cleanUrl.setUserInfo("")
        return cleanUrl
    
    def __findForm(self, webPage, data, boundary=None):
        """
        Private method to find the form used for logging in.
        
        @param webPage reference to the web page (QWebPage)
        @param data data to be sent (QByteArray)
        @keyparam boundary boundary string (QByteArray) for multipart encoded data,
            None for urlencoded data
        @return parsed form (LoginForm)
        """
        form = LoginForm()
        if boundary is not None:
            args = self.__extractMultipartQueryItems(data, boundary)
        else:
            argsUrl = QUrl.fromEncoded(
                QByteArray("foo://bar.com/?" + data.replace(b"+", b"%20")))
            encodedArgs = argsUrl.queryItems()
            args = set()
            for arg in encodedArgs:
                key = arg[0]
                value = arg[1]
                args.add((key, value))
        
        # extract the forms
        lst = webPage.mainFrame().evaluateJavaScript(parseForms_js)
        for map in lst:
            formHasPasswords = False
            formName = map["name"]
            formIndex = map["index"]
            elements = map["elements"]
            formElements = set()
            formElementTypes = {}
            deadElements = set()
            for elementMap in elements:
                try:
                    name = elementMap["name"]
                    value = elementMap["value"]
                    type_ = elementMap["type"]
                except KeyError:
                    continue
                if type_ == "password":
                    formHasPasswords = True
                t = (name, value)
                try:
                    if elementMap["autocomplete"] == "off":
                        deadElements.add(t)
                except KeyError:
                    pass
                if name:
                    formElements.add(t)
                    formElementTypes[name] = type_
            if formElements.intersection(args) == args:
                form.hasAPassword = formHasPasswords
                if not formName:
                    form.name = formIndex
                else:
                    form.name = formName
                args.difference_update(deadElements)
                for elt in deadElements:
                    if elt[0] in formElementTypes:
                        del formElementTypes[elt[0]]
                form.elements = list(args)
                form.elementTypes = formElementTypes
                break
        
        return form
    
    def __extractMultipartQueryItems(self, data, boundary):
        """
        Private method to extract the query items for a post operation.
        
        @param data data to be sent (QByteArray)
        @param boundary boundary string (QByteArray)
        @return set of name, value pairs (set of tuple of string, string)
        """
        args = set()
        
        dataStr = bytes(data).decode()
        boundaryStr = bytes(boundary).decode()
        
        parts = dataStr.split(boundaryStr + "\r\n")
        for part in parts:
            if part.startswith("Content-Disposition"):
                lines = part.split("\r\n")
                name = lines[0].split("=")[1][1:-1]
                value = lines[2]
                args.add((name, value))
        
        return args
    
    def fill(self, page):
        """
        Public slot to fill login forms with saved data.
        
        @param page reference to the web page (QWebPage)
        """
        if page is None or page.mainFrame() is None:
            return
        
        if not self.__loaded:
            self.__load()
        
        url = page.mainFrame().url()
        url = self.__stripUrl(url)
        key = self.__createKey(url, "")
        if key not in self.__loginForms or \
           key not in self.__logins:
            return
        
        form = self.__loginForms[key]
        if form.url != url:
            return
        
        if form.name == "":
            formName = "0"
        else:
            try:
                formName = "{0:d}".format(int(form.name))
            except ValueError:
                formName = '"{0}"'.format(form.name)
        for element in form.elements:
            name = element[0]
            value = element[1]
            
            disabled = page.mainFrame().evaluateJavaScript(
                'document.forms[{0}].elements["{1}"].disabled'.format(formName, name))
            if disabled:
                continue
            
            readOnly = page.mainFrame().evaluateJavaScript(
                'document.forms[{0}].elements["{1}"].readOnly'.format(formName, name))
            if readOnly:
                continue
            
            type_ = page.mainFrame().evaluateJavaScript(
                'document.forms[{0}].elements["{1}"].type'.format(formName, name))
            if type_ == "" or \
               type_ in ["hidden", "reset", "submit"]:
                continue
            if type_ == "password":
                value = Utilities.crypto.pwConvert(self.__logins[key][1], encode=False)
            setType = type_ == "checkbox" and "checked" or "value"
            value = value.replace("\\", "\\\\")
            value = value.replace('"', '\\"')
            javascript = 'document.forms[{0}].elements["{1}"].{2}="{3}";'.format(
                         formName, name, setType, value)
            page.mainFrame().evaluateJavaScript(javascript)
    
    def masterPasswordChanged(self, oldPassword, newPassword):
        """
        Public slot to handle the change of the master password.
        
        @param oldPassword current master password (string)
        @param newPassword new master password (string)
        """
        if not self.__loaded:
            self.__load()
        
        progress = QProgressDialog(self.trUtf8("Re-encoding saved passwords..."),
            None, 0, len(self.__logins), QApplication.activeModalWidget())
        progress.setMinimumDuration(0)
        count = 0
        
        for key in self.__logins:
            progress.setValue(count)
            QCoreApplication.processEvents()
            username, hash = self.__logins[key]
            hash = Utilities.crypto.pwRecode(hash, oldPassword, newPassword)
            self.__logins[key] = (username, hash)
            count += 1
        
        progress.setValue(len(self.__logins))
        QCoreApplication.processEvents()
        self.changed.emit()