/// <summary>
/// Fill this store with elements from an openssh known_hosts file
/// </summary>
/// <param name="filePath">The path of the file to read</param>
public void ImportKnownHostsFromFile(string filePath)
{
using (var fStream = File.OpenText(filePath))
{
while (!fStream.EndOfStream)
{
KnownHost createdHost;
if (KnownHost.TryParse(fStream.ReadLine(), out createdHost))
{
_knownHosts.Add(createdHost);
}
}
}
}
/// <summary>
/// Attempts to parse a line from an openssh known_hosts file
/// </summary>
/// <param name="hostLine"></param>
/// <param name="host"></param>
/// <returns><c>true</c> if the host line could be parsed. <c>false</c> if an error occurred</returns>
public static bool TryParse(string hostLine, out KnownHost host)
{
try
{
return(UnsafeTryParse(hostLine, out host));
}
catch (FormatException)
{
host = null;
return(false);
}
catch (ArgumentException)
{
host = null;
return(false);
}
}
/// <summary>
/// Add a host to this store.
/// </summary>
/// <param name="hostname">The name of the host to add</param>
/// <param name="portNumber"></param>
/// <param name="keyType">The algorithm of the public key</param>
/// <param name="pubKey">The public key of the host to add</param>
/// <param name="storeHostnameHashed">Whether the hostname should be stored as a SHA1 hash</param>
/// <param name="marker">An optional <c>@</c> prefixed string that corresponds to a marker for this host. See the <c>man 8 sshd</c> section about known_hosts for valid markers</param>
/// <exception cref="FormatException">Thrown if the given arguments cannor be parsed into a valid host entry</exception>
public void AddHost(string hostname, UInt16 portNumber, string keyType, byte[] pubKey, bool storeHostnameHashed, string marker = "")
{
string hostNameWithPort = string.Format("[{0}:{1}]", hostname, portNumber);
string hostnameSection;
if (!string.IsNullOrEmpty(marker))
{
if (!marker.StartsWith("@"))
{
throw new FormatException("The given host marker must be prefixed with \'@\'. See the \'man 8 sshd\' section about known_hosts for more details on markers");
}
marker = string.Format("{0} ", marker);
}
if (storeHostnameHashed)
{
byte[] salt = new byte[20];
Sftp.GeneXusSftpUtils.CryptoAbstractionSftp.GenerateRandom(salt);
HMACSHA1 hmac = new HMACSHA1(salt);
byte[] hash = hmac.ComputeHash(Encoding.ASCII.GetBytes(hostNameWithPort));
hostnameSection = string.Format("|1|{0}|{1}", Convert.ToBase64String(salt), Convert.ToBase64String(hash));
}
else
{
hostnameSection = hostNameWithPort;
}
string hostToParse = string.Format("{3}{0} {1} {2}", hostnameSection, keyType, Convert.ToBase64String(pubKey), marker);
KnownHost newHost;
if (!KnownHost.TryParse(hostToParse, out newHost))
{
throw new FormatException("Malformed input: Failed to create entry. If you specified a marker, ensure it is valid (see the \'man 8 sshd\' section on known_hosts for more details on markers)");
}
_knownHosts.Add(newHost);
}
private static bool UnsafeTryParse(string hostLine, out KnownHost host)
{
host = null;
if (string.IsNullOrEmpty(hostLine) || hostLine.StartsWith("#"))
{
return(false);
}
bool hasSpecialPrefix = hostLine.StartsWith("@");
string[] sectionedLine = hostLine.Split(' ');
if (hasSpecialPrefix && sectionedLine.Length < 4)
{
return(false);
}
else if (sectionedLine.Length < 3)
{
return(false);
}
HostPubkeyMarker marker =
hasSpecialPrefix ? ParseSpecialOperand(sectionedLine[0]) : HostPubkeyMarker.None;
if (marker == HostPubkeyMarker.Error)
{
return(false);
}
int sectionOffset = hasSpecialPrefix ? 1 : 0;
string hostNameSecion = sectionedLine[sectionOffset];
string keyTypeSection = sectionedLine[1 + sectionOffset];
string pubKeySection = sectionedLine[2 + sectionOffset];
host = new KnownHost(hostNameSecion, keyTypeSection, pubKeySection, marker);
return(true);
}
