Helpviewer/Passwords/PasswordManager.py

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

# Copyright (c) 2009 - 2012 Detlev Offenbach <detlev@die-offenbachs.de>
#

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

import os

from PyQt4.QtCore import pyqtSignal, QObject, QByteArray, QUrl, QCoreApplication, \
    QXmlStreamReader
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 .LoginForm import LoginForm
from .PasswordWriter import PasswordWriter
from .PasswordReader import PasswordReader

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


class PasswordManager(QObject):
    """
    Class implementing the password manager.
    
    @signal changed() emitted to indicate a change
    @signal passwordsSaved() emitted after the passwords were saved
    """
    changed = pyqtSignal()
    passwordsSaved = 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 getFileName(self):
        """
        Public method to get the file name of the passwords file.
        
        @return name of the passwords file (string)
        """
        return os.path.join(Utilities.getConfigDir(), "browser", "logins.xml")
    
    def save(self):
        """
        Public slot to save the login entries to disk.
        """
        if not self.__loaded:
            return
        
        loginFile = self.getFileName()
        writer = PasswordWriter()
        if not writer.write(loginFile, self.__logins, self.__loginForms, self.__never):
            E5MessageBox.critical(None,
                self.trUtf8("Saving login data"),
                self.trUtf8("""<p>Login data could not be saved to <b>{0}</b></p>"""
                            ).format(loginFile))
        else:
            self.passwordsSaved.emit()
    
    def __load(self):
        """
        Private method to load the saved login credentials.
        """
        loginFile = self.getFileName()
        if not os.path.exists(loginFile):
            self.__loadNonXml(os.path.splitext(loginFile)[0])
        else:
            reader = PasswordReader()
            self.__logins, self.__loginForms, self.__never = reader.read(loginFile)
            if reader.error() != QXmlStreamReader.NoError:
                E5MessageBox.warning(None,
                    self.trUtf8("Loading login data"),
                    self.trUtf8("""Error when loading login data on"""
                                """ line {0}, column {1}:\n{2}""")\
                        .format(reader.lineNumber(),
                                reader.columnNumber(),
                                reader.errorString()))
        
        self.__loaded = True
    
    def __loadNonXml(self, loginFile):
        """
        Private method to load non-XML password files.
        
        This method is to convert from the old, non-XML format to the new
        XML based format.
        
        @param loginFile name of the non-XML password file (string)
        """
        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.url = QUrl(data[1])
                        form.name = data[2]
                        form.hasAPassword = data[3] == "True"
                        for element in data[4:]:
                            name, value = element.split(" = ", 1)
                            form.elements.append((name, value))
                        self.__loginForms[key] = form
                        data = []
                
                elif section == 2:
                    self.__never.append(line)
            
            os.remove(loginFile)
        
        self.__loaded = True
        
        # this does the conversion
        self.save()
    
    def reload(self):
        """
        Public method to reload the login data.
        """
        if not self.__loaded:
            return
        
        self.__load()
    
    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()