/// <summary>
/// Continues authentication process.
/// </summary>
/// <param name="serverResponse">Server sent SASL response.</param>
/// <returns>Returns challange request what must be sent to server or null if authentication has completed.</returns>
/// <exception cref="ArgumentNullException">Is raised when <b>serverResponse</b> is null reference.</exception>
/// <exception cref="InvalidOperationException">Is raised when this method is called when authentication is completed.</exception>
public override byte[] Continue(byte[] serverResponse)
{
if (serverResponse == null)
{
throw new ArgumentNullException("serverResponse");
}
if (m_IsCompleted)
{
throw new InvalidOperationException("Authentication is completed.");
}
/* RFC 2831.
* The base64-decoded version of the SASL exchange is:
*
* S: realm="elwood.innosoft.com",nonce="OA6MG9tEQGm2hh",qop="auth",
* algorithm=md5-sess,charset=utf-8
* C: charset=utf-8,username="******",realm="elwood.innosoft.com",
* nonce="OA6MG9tEQGm2hh",nc=00000001,cnonce="OA6MHXh6VqTrRk",
* digest-uri="imap/elwood.innosoft.com",
* response=d388dad90d4bbd760a152321f2143af7,qop=auth
* S: rspauth=ea40f60335c427b5527b84dbabcdfffd
* C:
* S: ok
*
* The password in this example was "secret".
*/
if (m_State == 0)
{
m_State++;
// Parse server challenge.
AUTH_SASL_DigestMD5_Challenge challenge = AUTH_SASL_DigestMD5_Challenge.Parse(Encoding.UTF8.GetString(serverResponse));
// Construct our response to server challenge.
m_pResponse = new AUTH_SASL_DigestMD5_Response(
challenge,
challenge.Realm[0],
m_UserName,
m_Password,
Guid.NewGuid().ToString().Replace("-", ""),
1,
challenge.QopOptions[0],
m_Protocol + "/" + m_ServerName
);
return(Encoding.UTF8.GetBytes(m_pResponse.ToResponse()));
}
else if (m_State == 1)
{
m_State++;
m_IsCompleted = true;
// Check rspauth value.
if (!string.Equals(Encoding.UTF8.GetString(serverResponse), m_pResponse.ToRspauthResponse(m_UserName, m_Password), StringComparison.InvariantCultureIgnoreCase))
{
throw new Exception("Server server 'rspauth' value mismatch with local 'rspauth' value.");
}
return(new byte[0]);
}
else
{
throw new InvalidOperationException("Authentication is completed.");
}
}
/// <summary>
/// Parses DIGEST-MD5 response from response-string.
/// </summary>
/// <param name="digestResponse">Response string.</param>
/// <returns>Returns DIGEST-MD5 response.</returns>
/// <exception cref="ArgumentNullException">Is raised when <b>digestResponse</b> isnull reference.</exception>
/// <exception cref="ParseException">Is raised when response parsing + validation fails.</exception>
public static AUTH_SASL_DigestMD5_Response Parse(string digestResponse)
{
if (digestResponse == null)
{
throw new ArgumentNullException(digestResponse);
}
/* RFC 2831 2.1.2.
* The client makes note of the "digest-challenge" and then responds
* with a string formatted and computed according to the rules for a
* "digest-response" defined as follows:
*
* digest-response = 1#( username | realm | nonce | cnonce |
* nonce-count | qop | digest-uri | response |
* maxbuf | charset | cipher | authzid |
* auth-param )
*
* username = "******" "=" <"> username-value <">
* username-value = qdstr-val
* cnonce = "cnonce" "=" <"> cnonce-value <">
* cnonce-value = qdstr-val
* nonce-count = "nc" "=" nc-value
* nc-value = 8LHEX
* qop = "qop" "=" qop-value
* digest-uri = "digest-uri" "=" <"> digest-uri-value <">
* digest-uri-value = serv-type "/" host [ "/" serv-name ]
* serv-type = 1*ALPHA
* host = 1*( ALPHA | DIGIT | "-" | "." )
* serv-name = host
* response = "response" "=" response-value
* response-value = 32LHEX
* LHEX = "0" | "1" | "2" | "3" |
* "4" | "5" | "6" | "7" |
* "8" | "9" | "a" | "b" |
* "c" | "d" | "e" | "f"
* cipher = "cipher" "=" cipher-value
* authzid = "authzid" "=" <"> authzid-value <">
* authzid-value = qdstr-val
*/
AUTH_SASL_DigestMD5_Response retVal = new AUTH_SASL_DigestMD5_Response();
// Set default values.
retVal.m_Realm = "";
string[] parameters = TextUtils.SplitQuotedString(digestResponse, ',');
foreach (string parameter in parameters)
{
string[] name_value = parameter.Split(new char[] { '=' }, 2);
string name = name_value[0].Trim();
if (name_value.Length == 2)
{
if (name.ToLower() == "username")
{
retVal.m_UserName = TextUtils.UnQuoteString(name_value[1]);
}
else if (name.ToLower() == "realm")
{
retVal.m_Realm = TextUtils.UnQuoteString(name_value[1]);
}
else if (name.ToLower() == "nonce")
{
retVal.m_Nonce = TextUtils.UnQuoteString(name_value[1]);
}
else if (name.ToLower() == "cnonce")
{
retVal.m_Cnonce = TextUtils.UnQuoteString(name_value[1]);
}
else if (name.ToLower() == "nc")
{
retVal.m_NonceCount = Int32.Parse(TextUtils.UnQuoteString(name_value[1]), System.Globalization.NumberStyles.HexNumber);
}
else if (name.ToLower() == "qop")
{
retVal.m_Qop = TextUtils.UnQuoteString(name_value[1]);
}
else if (name.ToLower() == "digest-uri")
{
retVal.m_DigestUri = TextUtils.UnQuoteString(name_value[1]);
}
else if (name.ToLower() == "response")
{
retVal.m_Response = TextUtils.UnQuoteString(name_value[1]);
}
else if (name.ToLower() == "charset")
{
retVal.m_Charset = TextUtils.UnQuoteString(name_value[1]);
}
else if (name.ToLower() == "cipher")
{
retVal.m_Cipher = TextUtils.UnQuoteString(name_value[1]);
}
else if (name.ToLower() == "authzid")
{
retVal.m_Authzid = TextUtils.UnQuoteString(name_value[1]);
}
}
}
/* Validate required fields.
* Per RFC 2831 2.1.2. Only [username nonce cnonce nc response] parameters are required.
*/
if (string.IsNullOrEmpty(retVal.UserName))
{
throw new ParseException("The response-string doesn't contain required parameter 'username' value.");
}
if (string.IsNullOrEmpty(retVal.Nonce))
{
throw new ParseException("The response-string doesn't contain required parameter 'nonce' value.");
}
if (string.IsNullOrEmpty(retVal.Cnonce))
{
throw new ParseException("The response-string doesn't contain required parameter 'cnonce' value.");
}
if (retVal.NonceCount < 1)
{
throw new ParseException("The response-string doesn't contain required parameter 'nc' value.");
}
if (string.IsNullOrEmpty(retVal.Response))
{
throw new ParseException("The response-string doesn't contain required parameter 'response' value.");
}
return(retVal);
}
/// <summary>
/// Continues authentication process.
/// </summary>
/// <param name="clientResponse">Client sent SASL response.</param>
/// <returns>Retunrns challange response what must be sent to client or null if authentication has completed.</returns>
/// <exception cref="ArgumentNullException">Is raised when <b>clientResponse</b> is null reference.</exception>
public override byte[] Continue(byte[] clientResponse)
{
if (clientResponse == null)
{
throw new ArgumentNullException("clientResponse");
}
/* RFC 2831.
* The base64-decoded version of the SASL exchange is:
*
* S: realm="elwood.innosoft.com",nonce="OA6MG9tEQGm2hh",qop="auth",
* algorithm=md5-sess,charset=utf-8
* C: charset=utf-8,username="******",realm="elwood.innosoft.com",
* nonce="OA6MG9tEQGm2hh",nc=00000001,cnonce="OA6MHXh6VqTrRk",
* digest-uri="imap/elwood.innosoft.com",
* response=d388dad90d4bbd760a152321f2143af7,qop=auth
* S: rspauth=ea40f60335c427b5527b84dbabcdfffd
* C:
* S: ok
*
* The password in this example was "secret".
*/
if (m_State == 0)
{
m_State++;
AUTH_SASL_DigestMD5_Challenge callenge = new AUTH_SASL_DigestMD5_Challenge(new string[] { m_Realm }, m_Nonce, new string[] { "auth" }, false);
return(Encoding.UTF8.GetBytes(callenge.ToChallenge()));
}
else if (m_State == 1)
{
m_State++;
try{
AUTH_SASL_DigestMD5_Response response = AUTH_SASL_DigestMD5_Response.Parse(Encoding.UTF8.GetString(clientResponse));
// Check realm and nonce value.
if (m_Realm != response.Realm || m_Nonce != response.Nonce)
{
return(Encoding.UTF8.GetBytes("rspauth=\"\""));
}
m_UserName = response.UserName;
AUTH_e_UserInfo result = OnGetUserInfo(response.UserName);
if (result.UserExists)
{
if (response.Authenticate(result.UserName, result.Password))
{
m_IsAuthenticated = true;
return(Encoding.UTF8.GetBytes(response.ToRspauthResponse(result.UserName, result.Password)));
}
}
}
catch {
// Authentication failed, just reject request.
}
return(Encoding.UTF8.GetBytes("rspauth=\"\""));
}
else
{
m_IsCompleted = true;
}
return(null);
}
