bool SkipCommand(string command, byte[] buffer, ref int index, int endIndex)
{
while (index < endIndex && commandIndex < command.Length)
{
if (buffer[index] != (byte)command[commandIndex])
{
state = Pop3AuthCommandState.Error;
break;
}
commandIndex++;
index++;
}
return(commandIndex == command.Length);
}
IList <AuthenticationSecret> DetectApopSecrets(byte[] buffer, int offset, int endIndex)
{
var secrets = new List <AuthenticationSecret> ();
int index = offset;
int startIndex;
if (state == Pop3AuthCommandState.ApopNewLine)
{
return(EmptyAuthSecrets);
}
if (state == Pop3AuthCommandState.Apop)
{
if (SkipCommand("APOP ", buffer, ref index, endIndex))
{
state = Pop3AuthCommandState.ApopUserName;
}
if (index >= endIndex || state == Pop3AuthCommandState.Error)
{
return(EmptyAuthSecrets);
}
}
if (state == Pop3AuthCommandState.ApopUserName)
{
startIndex = index;
while (index < endIndex && buffer[index] != (byte)' ')
{
index++;
}
if (index > startIndex)
{
secrets.Add(new AuthenticationSecret(startIndex, index - startIndex));
}
if (index < endIndex)
{
state = Pop3AuthCommandState.ApopToken;
index++;
}
if (index >= endIndex)
{
return(secrets);
}
}
startIndex = index;
while (index < endIndex && buffer[index] != (byte)'\r')
{
index++;
}
if (index < endIndex)
{
state = Pop3AuthCommandState.ApopNewLine;
}
if (index > startIndex)
{
secrets.Add(new AuthenticationSecret(startIndex, index - startIndex));
}
return(secrets);
}
IList <AuthenticationSecret> DetectUserPassSecrets(byte[] buffer, int offset, int endIndex)
{
var secrets = new List <AuthenticationSecret> ();
int index = offset;
if (state == Pop3AuthCommandState.User)
{
if (SkipCommand("USER ", buffer, ref index, endIndex))
{
state = Pop3AuthCommandState.UserName;
}
if (index >= endIndex || state == Pop3AuthCommandState.Error)
{
return(EmptyAuthSecrets);
}
}
if (state == Pop3AuthCommandState.UserName)
{
int startIndex = index;
while (index < endIndex && buffer[index] != (byte)'\r')
{
index++;
}
if (index > startIndex)
{
secrets.Add(new AuthenticationSecret(startIndex, index - startIndex));
}
if (index < endIndex)
{
state = Pop3AuthCommandState.UserNewLine;
index++;
}
if (index >= endIndex)
{
return(secrets);
}
}
if (state == Pop3AuthCommandState.UserNewLine)
{
if (buffer[index] == (byte)'\n')
{
state = Pop3AuthCommandState.Pass;
commandIndex = 0;
index++;
}
else
{
state = Pop3AuthCommandState.Error;
}
if (index >= endIndex || state == Pop3AuthCommandState.Error)
{
return(secrets);
}
}
if (state == Pop3AuthCommandState.Pass)
{
if (SkipCommand("PASS ", buffer, ref index, endIndex))
{
state = Pop3AuthCommandState.Password;
}
if (index >= endIndex || state == Pop3AuthCommandState.Error)
{
return(EmptyAuthSecrets);
}
}
if (state == Pop3AuthCommandState.Password)
{
int startIndex = index;
while (index < endIndex && buffer[index] != (byte)'\r')
{
index++;
}
if (index > startIndex)
{
secrets.Add(new AuthenticationSecret(startIndex, index - startIndex));
}
if (index < endIndex)
{
state = Pop3AuthCommandState.PassNewLine;
index++;
}
if (index >= endIndex)
{
return(secrets);
}
}
if (state == Pop3AuthCommandState.PassNewLine)
{
if (buffer[index] == (byte)'\n')
{
state = Pop3AuthCommandState.None;
commandIndex = 0;
index++;
}
else
{
state = Pop3AuthCommandState.Error;
}
}
return(secrets);
}
public IList <AuthenticationSecret> DetectSecrets(byte[] buffer, int offset, int count)
{
if (!IsAuthenticating || state == Pop3AuthCommandState.Error || count == 0)
{
return(EmptyAuthSecrets);
}
int endIndex = offset + count;
int index = offset;
if (state == Pop3AuthCommandState.None)
{
switch ((char)buffer[index])
{
case 'A':
state = Pop3AuthCommandState.A;
index++;
break;
case 'U':
state = Pop3AuthCommandState.User;
commandIndex = 1;
index++;
break;
default:
state = Pop3AuthCommandState.Error;
break;
}
if (index >= endIndex || state == Pop3AuthCommandState.Error)
{
return(EmptyAuthSecrets);
}
}
if (state == Pop3AuthCommandState.A)
{
switch ((char)buffer[index])
{
case 'P':
state = Pop3AuthCommandState.Apop;
commandIndex = 2;
index++;
break;
case 'U':
state = Pop3AuthCommandState.Auth;
commandIndex = 2;
index++;
break;
default:
state = Pop3AuthCommandState.Error;
break;
}
if (index >= endIndex || state == Pop3AuthCommandState.Error)
{
return(EmptyAuthSecrets);
}
}
if (state >= Pop3AuthCommandState.Apop && state <= Pop3AuthCommandState.ApopNewLine)
{
return(DetectApopSecrets(buffer, index, endIndex));
}
if (state >= Pop3AuthCommandState.Auth && state <= Pop3AuthCommandState.AuthToken)
{
return(DetectAuthSecrets(buffer, index, endIndex));
}
return(DetectUserPassSecrets(buffer, index, endIndex));
}
IList <AuthenticationSecret> DetectAuthSecrets(byte[] buffer, int offset, int endIndex)
{
int index = offset;
if (state == Pop3AuthCommandState.Auth)
{
if (SkipCommand("AUTH ", buffer, ref index, endIndex))
{
state = Pop3AuthCommandState.AuthMechanism;
}
if (index >= endIndex || state == Pop3AuthCommandState.Error)
{
return(EmptyAuthSecrets);
}
}
if (state == Pop3AuthCommandState.AuthMechanism)
{
while (index < endIndex && buffer[index] != (byte)' ' && buffer[index] != (byte)'\r')
{
index++;
}
if (index < endIndex)
{
if (buffer[index] == (byte)' ')
{
state = Pop3AuthCommandState.AuthToken;
}
else
{
state = Pop3AuthCommandState.AuthNewLine;
}
index++;
}
if (index >= endIndex)
{
return(EmptyAuthSecrets);
}
}
if (state == Pop3AuthCommandState.AuthNewLine)
{
if (buffer[index] == (byte)'\n')
{
state = Pop3AuthCommandState.AuthToken;
index++;
}
else
{
state = Pop3AuthCommandState.Error;
}
if (index >= endIndex || state == Pop3AuthCommandState.Error)
{
return(EmptyAuthSecrets);
}
}
int startIndex = index;
while (index < endIndex && buffer[index] != (byte)'\r')
{
index++;
}
if (index < endIndex)
{
state = Pop3AuthCommandState.AuthNewLine;
}
if (index == startIndex)
{
return(EmptyAuthSecrets);
}
var secret = new AuthenticationSecret(startIndex, index - startIndex);
if (state == Pop3AuthCommandState.AuthNewLine)
{
index++;
if (index < endIndex)
{
if (buffer[index] == (byte)'\n')
{
state = Pop3AuthCommandState.AuthToken;
}
else
{
state = Pop3AuthCommandState.Error;
}
}
}
return(new AuthenticationSecret[] { secret });
}
