132 lines
4.2 KiB
C#
132 lines
4.2 KiB
C#
//
|
|
// System.Collections.SecureHashCodeProvider.cs
|
|
//
|
|
// Authors:
|
|
// Sergey Chaban (serge@wildwestsoftware.com)
|
|
// Andreas Nahr (ClassDevelopment@A-SoftTech.com)
|
|
// Sebastien Pouliot <sebastien@ximian.com>
|
|
//
|
|
// Copyright (C) 2004-2005 Novell, Inc (http://www.novell.com)
|
|
// Copyright 2012 Xamarin, Inc (http://xamarin.com)
|
|
//
|
|
// Permission is hereby granted, free of charge, to any person obtaining
|
|
// a copy of this software and associated documentation files (the
|
|
// "Software"), to deal in the Software without restriction, including
|
|
// without limitation the rights to use, copy, modify, merge, publish,
|
|
// distribute, sublicense, and/or sell copies of the Software, and to
|
|
// permit persons to whom the Software is furnished to do so, subject to
|
|
// the following conditions:
|
|
//
|
|
// The above copyright notice and this permission notice shall be
|
|
// included in all copies or substantial portions of the Software.
|
|
//
|
|
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
|
|
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
|
|
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
|
|
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
|
|
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
|
|
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
|
|
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
|
|
//
|
|
using System;
|
|
using System.Collections;
|
|
using System.Globalization;
|
|
|
|
namespace System.Web.Util
|
|
{
|
|
class SecureHashCodeProvider : IHashCodeProvider
|
|
{
|
|
static readonly SecureHashCodeProvider singletonInvariant = new SecureHashCodeProvider (CultureInfo.InvariantCulture);
|
|
static SecureHashCodeProvider singleton;
|
|
static readonly object sync = new object ();
|
|
static readonly int seed;
|
|
|
|
TextInfo m_text; // must match MS name for serialization
|
|
|
|
public static SecureHashCodeProvider Default {
|
|
get {
|
|
lock (sync) {
|
|
if (singleton == null) {
|
|
singleton = new SecureHashCodeProvider ();
|
|
} else if (singleton.m_text == null) {
|
|
if (!AreEqual (CultureInfo.CurrentCulture, CultureInfo.InvariantCulture))
|
|
singleton = new SecureHashCodeProvider ();
|
|
} else if (!AreEqual (singleton.m_text, CultureInfo.CurrentCulture)) {
|
|
singleton = new SecureHashCodeProvider ();
|
|
}
|
|
return singleton;
|
|
}
|
|
}
|
|
}
|
|
|
|
public static SecureHashCodeProvider DefaultInvariant {
|
|
get { return singletonInvariant; }
|
|
}
|
|
|
|
static SecureHashCodeProvider ()
|
|
{
|
|
// It should be enough to fend off the attack described in
|
|
// https://bugzilla.novell.com/show_bug.cgi?id=739119
|
|
// In order to predict value of the seed, the attacker would have to know the exact time when
|
|
// the server process started and since it's a remote attack, this is next to impossible.
|
|
// Using milliseconds instead of ticks here would make it easier for the attackers since there
|
|
// would only be as many as 1000 possible values
|
|
seed = (int)DateTime.UtcNow.Ticks;
|
|
}
|
|
|
|
// Public instance constructor
|
|
public SecureHashCodeProvider ()
|
|
{
|
|
CultureInfo culture = CultureInfo.CurrentCulture;
|
|
if (!AreEqual (culture, CultureInfo.InvariantCulture))
|
|
m_text = CultureInfo.CurrentCulture.TextInfo;
|
|
}
|
|
|
|
public SecureHashCodeProvider (CultureInfo culture)
|
|
{
|
|
if (culture == null)
|
|
throw new ArgumentNullException ("culture");
|
|
if (!AreEqual (culture, CultureInfo.InvariantCulture))
|
|
m_text = culture.TextInfo;
|
|
}
|
|
|
|
static bool AreEqual (CultureInfo a, CultureInfo b)
|
|
{
|
|
return a.LCID == b.LCID;
|
|
}
|
|
|
|
static bool AreEqual (TextInfo info, CultureInfo culture)
|
|
{
|
|
return info.LCID == culture.LCID;
|
|
}
|
|
|
|
public int GetHashCode (object obj)
|
|
{
|
|
if (obj == null)
|
|
throw new ArgumentNullException ("obj");
|
|
|
|
string str = obj as string;
|
|
|
|
if (str == null)
|
|
return obj.GetHashCode ();
|
|
|
|
int h = seed;
|
|
char c;
|
|
|
|
if ((m_text != null) && !AreEqual (m_text, CultureInfo.InvariantCulture)) {
|
|
str = m_text.ToLower (str);
|
|
for (int i = 0; i < str.Length; i++) {
|
|
c = str [i];
|
|
h = h * 31 + c;
|
|
}
|
|
} else {
|
|
for (int i = 0; i < str.Length; i++) {
|
|
c = Char.ToLower (str [i], CultureInfo.InvariantCulture);
|
|
h = h * 31 + c;
|
|
}
|
|
}
|
|
return h;
|
|
}
|
|
}
|
|
}
|