// [ ENTRY POINT ]
// Given the serialized string representations of a cookie & form token,
// validates that the pair is OK for this request.
public void Validate(HttpContextBase httpContext, string cookieToken, string formToken)
{
CheckSSLConfig(httpContext);
// Extract cookie & form tokens
AntiForgeryToken deserializedCookieToken = DeserializeToken(cookieToken);
AntiForgeryToken deserializedFormToken = DeserializeToken(formToken);
// Validate
_validator.ValidateTokens(httpContext, ExtractIdentity(httpContext), deserializedCookieToken, deserializedFormToken);
}
// [ ENTRY POINT ]
// Given an HttpContext, validates that the anti-XSRF tokens contained
// in the cookies & form are OK for this request.
public void Validate(HttpContextBase httpContext)
{
CheckSSLConfig(httpContext);
// Extract cookie & form tokens
AntiForgeryToken cookieToken = _tokenStore.GetCookieToken(httpContext);
AntiForgeryToken formToken = _tokenStore.GetFormToken(httpContext);
// Validate
_validator.ValidateTokens(httpContext, ExtractIdentity(httpContext), cookieToken, formToken);
}
// [ ENTRY POINT ]
// Generates a (cookie, form) serialized token pair for the current user.
// The caller may specify an existing cookie value if one exists. If the
// 'new cookie value' out param is non-null, the caller *must* persist
// the new value to cookie storage since the original value was null or
// invalid. This method is side-effect free.
public void GetTokens(HttpContextBase httpContext, string serializedOldCookieToken, out string serializedNewCookieToken, out string serializedFormToken)
{
CheckSSLConfig(httpContext);
AntiForgeryToken oldCookieToken = DeserializeTokenNoThrow(serializedOldCookieToken);
AntiForgeryToken newCookieToken, formToken;
GetTokens(httpContext, oldCookieToken, out newCookieToken, out formToken);
serializedNewCookieToken = Serialize(newCookieToken);
serializedFormToken = Serialize(formToken);
}
private void GetTokens(HttpContextBase httpContext, AntiForgeryToken oldCookieToken, out AntiForgeryToken newCookieToken, out AntiForgeryToken formToken)
{
newCookieToken = null;
if (!_validator.IsCookieTokenValid(oldCookieToken))
{
// Need to make sure we're always operating with a good cookie token.
oldCookieToken = newCookieToken = _validator.GenerateCookieToken();
}
#if NET_4_0
Contract.Assert(_validator.IsCookieTokenValid(oldCookieToken));
#endif
formToken = _validator.GenerateFormToken(httpContext, ExtractIdentity(httpContext), oldCookieToken);
}
public void ValidateTokens(HttpContextBase httpContext, IIdentity identity, AntiForgeryToken sessionToken, AntiForgeryToken fieldToken)
{
// Were the tokens even present at all?
if (sessionToken == null) {
throw HttpAntiForgeryException.CreateCookieMissingException(_config.CookieName);
}
if (fieldToken == null) {
throw HttpAntiForgeryException.CreateFormFieldMissingException(_config.FormFieldName);
}
// Do the tokens have the correct format?
if (!sessionToken.IsSessionToken || fieldToken.IsSessionToken) {
throw HttpAntiForgeryException.CreateTokensSwappedException(_config.CookieName, _config.FormFieldName);
}
// Are the security tokens embedded in each incoming token identical?
if (!Equals(sessionToken.SecurityToken, fieldToken.SecurityToken)) {
throw HttpAntiForgeryException.CreateSecurityTokenMismatchException();
}
// Is the incoming token meant for the current user?
string currentUsername = String.Empty;
BinaryBlob currentClaimUid = null;
if (identity != null && identity.IsAuthenticated) {
currentClaimUid = _claimUidExtractor.ExtractClaimUid(identity);
if (currentClaimUid == null) {
currentUsername = identity.Name ?? String.Empty;
}
}
// OpenID and other similar authentication schemes use URIs for the username.
// These should be treated as case-sensitive.
bool useCaseSensitiveUsernameComparison = currentUsername.StartsWith("http://", StringComparison.OrdinalIgnoreCase)
|| currentUsername.StartsWith("https://", StringComparison.OrdinalIgnoreCase);
if (!String.Equals(fieldToken.Username, currentUsername, (useCaseSensitiveUsernameComparison) ? StringComparison.Ordinal : StringComparison.OrdinalIgnoreCase)) {
throw HttpAntiForgeryException.CreateUsernameMismatchException(fieldToken.Username, currentUsername);
}
if (!Equals(fieldToken.ClaimUid, currentClaimUid)) {
throw HttpAntiForgeryException.CreateClaimUidMismatchException();
}
// Is the AdditionalData valid?
if (_config.AdditionalDataProvider != null && !_config.AdditionalDataProvider.ValidateAdditionalData(httpContext, fieldToken.AdditionalData)) {
throw HttpAntiForgeryException.CreateAdditionalDataCheckFailedException();
}
}
public AntiForgeryToken GenerateFormToken(HttpContextBase httpContext, IIdentity identity, AntiForgeryToken cookieToken)
{
#if NET_4_0
Contract.Assert(IsCookieTokenValid(cookieToken));
#endif
AntiForgeryToken formToken = new AntiForgeryToken()
{
SecurityToken = cookieToken.SecurityToken,
IsSessionToken = false
};
bool requireAuthenticatedUserHeuristicChecks = false;
// populate Username and ClaimUid
if (identity != null && identity.IsAuthenticated)
{
if (!_config.SuppressIdentityHeuristicChecks)
{
// If the user is authenticated and heuristic checks are not suppressed,
// then Username, ClaimUid, or AdditionalData must be set.
requireAuthenticatedUserHeuristicChecks = true;
}
formToken.ClaimUid = _claimUidExtractor.ExtractClaimUid(identity);
if (formToken.ClaimUid == null)
{
formToken.Username = identity.Name;
}
}
// populate AdditionalData
if (_config.AdditionalDataProvider != null)
{
formToken.AdditionalData = _config.AdditionalDataProvider.GetAdditionalData(httpContext);
}
if (requireAuthenticatedUserHeuristicChecks &&
String.IsNullOrEmpty(formToken.Username) &&
formToken.ClaimUid == null &&
String.IsNullOrEmpty(formToken.AdditionalData))
{
// Application says user is authenticated, but we have no identifier for the user.
throw new InvalidOperationException(String.Format(CultureInfo.CurrentCulture,
MvcResources.TokenValidator_AuthenticatedUserWithoutUsername, identity.GetType()));
}
return(formToken);
}
public void SaveCookieToken(HttpContextBase httpContext, AntiForgeryToken token)
{
string serializedToken = _serializer.Serialize(token);
HttpCookie newCookie = new HttpCookie(_config.CookieName, serializedToken)
{
HttpOnly = true
};
// Note: don't use "newCookie.Secure = _config.RequireSSL;" since the default
// value of newCookie.Secure is automatically populated from the <httpCookies>
// config element.
if (_config.RequireSSL) {
newCookie.Secure = true;
}
httpContext.Response.Cookies.Set(newCookie);
}
public void SaveCookieToken(HttpContextBase httpContext, AntiForgeryToken token)
{
string serializedToken = _serializer.Serialize(token);
HttpCookie newCookie = new HttpCookie(_config.CookieName, serializedToken)
{
HttpOnly = true
};
// Note: don't use "newCookie.Secure = _config.RequireSSL;" since the default
// value of newCookie.Secure is automatically populated from the <httpCookies>
// config element.
if (_config.RequireSSL)
{
newCookie.Secure = true;
}
httpContext.Response.Cookies.Set(newCookie);
}
public AntiForgeryToken Deserialize(string serializedToken)
{
try {
using (MemoryStream stream = new MemoryStream(_cryptoSystem.Unprotect(serializedToken))) {
using (BinaryReader reader = new BinaryReader(stream)) {
AntiForgeryToken token = DeserializeImpl(reader);
if (token != null)
{
return(token);
}
}
}
} catch {
// swallow all exceptions - homogenize error if something went wrong
}
// if we reached this point, something went wrong deserializing
throw HttpAntiForgeryException.CreateDeserializationFailedException();
}
public AntiForgeryToken GenerateFormToken(HttpContextBase httpContext, IIdentity identity, AntiForgeryToken cookieToken)
{
#if NET_4_0
Contract.Assert(IsCookieTokenValid(cookieToken));
#endif
AntiForgeryToken formToken = new AntiForgeryToken()
{
SecurityToken = cookieToken.SecurityToken,
IsSessionToken = false
};
bool requireAuthenticatedUserHeuristicChecks = false;
// populate Username and ClaimUid
if (identity != null && identity.IsAuthenticated) {
if (!_config.SuppressIdentityHeuristicChecks) {
// If the user is authenticated and heuristic checks are not suppressed,
// then Username, ClaimUid, or AdditionalData must be set.
requireAuthenticatedUserHeuristicChecks = true;
}
formToken.ClaimUid = _claimUidExtractor.ExtractClaimUid(identity);
if (formToken.ClaimUid == null) {
formToken.Username = identity.Name;
}
}
// populate AdditionalData
if (_config.AdditionalDataProvider != null) {
formToken.AdditionalData = _config.AdditionalDataProvider.GetAdditionalData(httpContext);
}
if (requireAuthenticatedUserHeuristicChecks
&& String.IsNullOrEmpty(formToken.Username)
&& formToken.ClaimUid == null
&& String.IsNullOrEmpty(formToken.AdditionalData)) {
// Application says user is authenticated, but we have no identifier for the user.
throw new InvalidOperationException(String.Format(CultureInfo.CurrentCulture,
MvcResources.TokenValidator_AuthenticatedUserWithoutUsername, identity.GetType()));
}
return formToken;
}
/* The serialized format of the anti-XSRF token is as follows:
* Version: 1 byte integer
* SecurityToken: 16 byte binary blob
* IsSessionToken: 1 byte Boolean
* [if IsSessionToken = true]
* +- IsClaimsBased: 1 byte Boolean
* | [if IsClaimsBased = true]
* | `- ClaimUid: 32 byte binary blob
* | [if IsClaimsBased = false]
* | `- Username: UTF-8 string with 7-bit integer length prefix
* `- AdditionalData: UTF-8 string with 7-bit integer length prefix
*/
private static AntiForgeryToken DeserializeImpl(BinaryReader reader)
{
// we can only consume tokens of the same serialized version that we generate
byte embeddedVersion = reader.ReadByte();
if (embeddedVersion != TokenVersion)
{
return(null);
}
AntiForgeryToken deserializedToken = new AntiForgeryToken();
byte[] securityTokenBytes = reader.ReadBytes(AntiForgeryToken.SecurityTokenBitLength / 8);
deserializedToken.SecurityToken = new BinaryBlob(AntiForgeryToken.SecurityTokenBitLength, securityTokenBytes);
deserializedToken.IsSessionToken = reader.ReadBoolean();
if (!deserializedToken.IsSessionToken)
{
bool isClaimsBased = reader.ReadBoolean();
if (isClaimsBased)
{
byte[] claimUidBytes = reader.ReadBytes(AntiForgeryToken.ClaimUidBitLength / 8);
deserializedToken.ClaimUid = new BinaryBlob(AntiForgeryToken.ClaimUidBitLength, claimUidBytes);
}
else
{
deserializedToken.Username = reader.ReadString();
}
deserializedToken.AdditionalData = reader.ReadString();
}
// if there's still unconsumed data in the stream, fail
if (reader.BaseStream.ReadByte() != -1)
{
return(null);
}
// success
return(deserializedToken);
}
// [ ENTRY POINT ]
// Generates an anti-XSRF token pair for the current user. The return
// value is the hidden input form element that should be rendered in
// the <form>. This method has a side effect: it may set a response
// cookie.
public TagBuilder GetFormInputElement(HttpContextBase httpContext)
{
CheckSSLConfig(httpContext);
AntiForgeryToken oldCookieToken = GetCookieTokenNoThrow(httpContext);
AntiForgeryToken newCookieToken, formToken;
GetTokens(httpContext, oldCookieToken, out newCookieToken, out formToken);
if (newCookieToken != null)
{
// If a new cookie was generated, persist it.
_tokenStore.SaveCookieToken(httpContext, newCookieToken);
}
// <input type="hidden" name="__AntiForgeryToken" value="..." />
TagBuilder retVal = new TagBuilder("input");
retVal.Attributes["type"] = "hidden";
retVal.Attributes["name"] = _config.FormFieldName;
retVal.Attributes["value"] = _serializer.Serialize(formToken);
return(retVal);
}
private void GetTokens(HttpContextBase httpContext, AntiForgeryToken oldCookieToken, out AntiForgeryToken newCookieToken, out AntiForgeryToken formToken)
{
newCookieToken = null;
if (!_validator.IsCookieTokenValid(oldCookieToken)) {
// Need to make sure we're always operating with a good cookie token.
oldCookieToken = newCookieToken = _validator.GenerateCookieToken();
}
#if NET_4_0
Contract.Assert(_validator.IsCookieTokenValid(oldCookieToken));
#endif
formToken = _validator.GenerateFormToken(httpContext, ExtractIdentity(httpContext), oldCookieToken);
}
public bool IsCookieTokenValid(AntiForgeryToken cookieToken)
{
return (cookieToken != null && cookieToken.IsSessionToken);
}
private string Serialize(AntiForgeryToken token)
{
return((token != null) ? _serializer.Serialize(token) : null);
}
private string Serialize(AntiForgeryToken token)
{
return (token != null) ? _serializer.Serialize(token) : null;
}
public void ValidateTokens(HttpContextBase httpContext, IIdentity identity, AntiForgeryToken sessionToken, AntiForgeryToken fieldToken)
{
// Were the tokens even present at all?
if (sessionToken == null)
{
throw HttpAntiForgeryException.CreateCookieMissingException(_config.CookieName);
}
if (fieldToken == null)
{
throw HttpAntiForgeryException.CreateFormFieldMissingException(_config.FormFieldName);
}
// Do the tokens have the correct format?
if (!sessionToken.IsSessionToken || fieldToken.IsSessionToken)
{
throw HttpAntiForgeryException.CreateTokensSwappedException(_config.CookieName, _config.FormFieldName);
}
// Are the security tokens embedded in each incoming token identical?
if (!Equals(sessionToken.SecurityToken, fieldToken.SecurityToken))
{
throw HttpAntiForgeryException.CreateSecurityTokenMismatchException();
}
// Is the incoming token meant for the current user?
string currentUsername = String.Empty;
BinaryBlob currentClaimUid = null;
if (identity != null && identity.IsAuthenticated)
{
currentClaimUid = _claimUidExtractor.ExtractClaimUid(identity);
if (currentClaimUid == null)
{
currentUsername = identity.Name ?? String.Empty;
}
}
// OpenID and other similar authentication schemes use URIs for the username.
// These should be treated as case-sensitive.
bool useCaseSensitiveUsernameComparison = currentUsername.StartsWith("http://", StringComparison.OrdinalIgnoreCase) ||
currentUsername.StartsWith("https://", StringComparison.OrdinalIgnoreCase);
if (!String.Equals(fieldToken.Username, currentUsername, (useCaseSensitiveUsernameComparison) ? StringComparison.Ordinal : StringComparison.OrdinalIgnoreCase))
{
throw HttpAntiForgeryException.CreateUsernameMismatchException(fieldToken.Username, currentUsername);
}
if (!Equals(fieldToken.ClaimUid, currentClaimUid))
{
throw HttpAntiForgeryException.CreateClaimUidMismatchException();
}
// Is the AdditionalData valid?
if (_config.AdditionalDataProvider != null && !_config.AdditionalDataProvider.ValidateAdditionalData(httpContext, fieldToken.AdditionalData))
{
throw HttpAntiForgeryException.CreateAdditionalDataCheckFailedException();
}
}
public bool IsCookieTokenValid(AntiForgeryToken cookieToken)
{
return(cookieToken != null && cookieToken.IsSessionToken);
}