IList<AuthenticationSecret> DetectLoginSecrets (byte[] buffer, int offset, int endIndex)
{
var secrets = new List<AuthenticationSecret> ();
int index = offset;
if (commandState == ImapAuthCommandState.LoginNewLine)
return EmptyAuthSecrets;
if (commandState == ImapAuthCommandState.Login) {
if (SkipText ("LOGIN ", buffer, ref index, endIndex))
commandState = ImapAuthCommandState.UserName;
if (index >= endIndex || commandState == ImapAuthCommandState.Error)
return EmptyAuthSecrets;
}
if (commandState == ImapAuthCommandState.UserName) {
if (SkipLoginToken (secrets, buffer, ref index, endIndex, (byte) ' ')) {
commandState = ImapAuthCommandState.Password;
ClearLoginTokenState ();
}
if (index >= endIndex || commandState == ImapAuthCommandState.Error)
return secrets;
}
if (commandState == ImapAuthCommandState.Password) {
if (SkipLoginToken (secrets, buffer, ref index, endIndex, (byte) '\r')) {
commandState = ImapAuthCommandState.LoginNewLine;
ClearLoginTokenState ();
}
}
return secrets;
}
IList<AuthenticationSecret> DetectAuthSecrets (byte[] buffer, int offset, int endIndex)
{
int index = offset;
if (commandState == ImapAuthCommandState.Authenticate) {
if (SkipText ("AUTHENTICATE ", buffer, ref index, endIndex))
commandState = ImapAuthCommandState.AuthMechanism;
if (index >= endIndex || commandState == ImapAuthCommandState.Error)
return EmptyAuthSecrets;
}
if (commandState == ImapAuthCommandState.AuthMechanism) {
while (index < endIndex && buffer[index] != (byte) ' ' && buffer[index] != (byte) '\r')
index++;
if (index < endIndex) {
if (buffer[index] == (byte) ' ') {
commandState = ImapAuthCommandState.AuthToken;
} else {
commandState = ImapAuthCommandState.AuthNewLine;
}
index++;
}
if (index >= endIndex)
return EmptyAuthSecrets;
}
if (commandState == ImapAuthCommandState.AuthNewLine) {
if (buffer[index] == (byte) '\n') {
commandState = ImapAuthCommandState.AuthToken;
index++;
} else {
commandState = ImapAuthCommandState.Error;
}
if (index >= endIndex || commandState == ImapAuthCommandState.Error)
return EmptyAuthSecrets;
}
int startIndex = index;
while (index < endIndex && buffer[index] != (byte) '\r')
index++;
if (index < endIndex)
commandState = ImapAuthCommandState.AuthNewLine;
if (index == startIndex)
return EmptyAuthSecrets;
var secret = new AuthenticationSecret (startIndex, index - startIndex);
return new AuthenticationSecret[] { secret };
}
bool SkipText (string text, byte[] buffer, ref int index, int endIndex)
{
while (index < endIndex && textIndex < text.Length) {
if (buffer[index] != (byte) text[textIndex]) {
commandState = ImapAuthCommandState.Error;
break;
}
textIndex++;
index++;
}
return textIndex == text.Length;
}
public IList<AuthenticationSecret> DetectSecrets (byte[] buffer, int offset, int count)
{
if (!IsAuthenticating || commandState == ImapAuthCommandState.Error || count == 0)
return EmptyAuthSecrets;
int endIndex = offset + count;
int index = offset;
if (commandState == ImapAuthCommandState.None) {
// skip over the tag
while (index < endIndex && buffer[index] != (byte) ' ')
index++;
if (index < endIndex) {
commandState = ImapAuthCommandState.Command;
index++;
}
if (index >= endIndex)
return EmptyAuthSecrets;
}
if (commandState == ImapAuthCommandState.Command) {
switch ((char) buffer[index]) {
case 'A':
commandState = ImapAuthCommandState.Authenticate;
textIndex = 1;
index++;
break;
case 'L':
commandState = ImapAuthCommandState.Login;
textIndex = 1;
index++;
break;
default:
commandState = ImapAuthCommandState.Error;
break;
}
if (index >= endIndex || commandState == ImapAuthCommandState.Error)
return EmptyAuthSecrets;
}
if (commandState >= ImapAuthCommandState.Authenticate && commandState <= ImapAuthCommandState.AuthToken)
return DetectAuthSecrets (buffer, index, endIndex);
return DetectLoginSecrets (buffer, index, endIndex);
}
bool SkipLoginToken (List<AuthenticationSecret> secrets, byte[] buffer, ref int index, int endIndex, byte sentinel)
{
int startIndex;
if (tokenType == ImapLoginTokenType.None) {
switch ((char) buffer[index]) {
case '{':
literalState = ImapLiteralState.Octets;
tokenType = ImapLoginTokenType.Literal;
index++;
break;
case '"':
tokenType = ImapLoginTokenType.QString;
index++;
break;
default:
tokenType = ImapLoginTokenType.Atom;
break;
}
}
switch (tokenType) {
case ImapLoginTokenType.Literal:
return SkipLiteralToken (secrets, buffer, ref index, endIndex, sentinel);
case ImapLoginTokenType.QString:
if (qstringState != ImapQStringState.Complete) {
startIndex = index;
while (index < endIndex) {
if (qstringState == ImapQStringState.Escaped) {
qstringState = ImapQStringState.None;
} else if (buffer[index] == (byte) '\\') {
qstringState = ImapQStringState.Escaped;
} else if (buffer[index] == (byte) '"') {
qstringState = ImapQStringState.EndQuote;
break;
}
index++;
}
if (index > startIndex)
secrets.Add (new AuthenticationSecret (startIndex, index - startIndex));
if (qstringState == ImapQStringState.EndQuote) {
qstringState = ImapQStringState.Complete;
index++;
}
}
if (index >= endIndex)
return false;
if (buffer[index] != sentinel) {
commandState = ImapAuthCommandState.Error;
return false;
}
index++;
return true;
default:
startIndex = index;
while (index < endIndex && buffer[index] != sentinel)
index++;
if (index > startIndex)
secrets.Add (new AuthenticationSecret (startIndex, index - startIndex));
if (index >= endIndex)
return false;
index++;
return true;
}
}
