diff options
Diffstat (limited to 'ExternalConnectors/PuttyKeyFileGenerator.cs')
| -rw-r--r-- | ExternalConnectors/PuttyKeyFileGenerator.cs | 109 |
1 files changed, 109 insertions, 0 deletions
diff --git a/ExternalConnectors/PuttyKeyFileGenerator.cs b/ExternalConnectors/PuttyKeyFileGenerator.cs new file mode 100644 index 00000000..6c62bca7 --- /dev/null +++ b/ExternalConnectors/PuttyKeyFileGenerator.cs @@ -0,0 +1,109 @@ +using System.Security.Cryptography; +using System.Text; +using System.Text.RegularExpressions; + +namespace ExternalConnectors; + +public class PuttyKeyFileGenerator +{ + private const int prefixSize = 4; + private const int paddedPrefixSize = prefixSize + 1; + private const int lineLength = 64; + private const string keyType = "ssh-rsa"; + private const string encryptionType = "none"; + + // source from + // https://gist.github.com/canton7/5670788?permalink_comment_id=3240331 + // https://gist.github.com/bosima/ee6630d30b533c7d7b2743a849e9b9d0 + + public static string ToPuttyPrivateKey(RSACryptoServiceProvider cryptoServiceProvider, string Comment = "imported-openssh-key") + { + var publicParameters = cryptoServiceProvider.ExportParameters(false); + byte[] publicBuffer = new byte[3 + keyType.Length + GetPrefixSize(publicParameters.Exponent) + publicParameters.Exponent.Length + + GetPrefixSize(publicParameters.Modulus) + publicParameters.Modulus.Length + 1]; + + using (var bw = new BinaryWriter(new MemoryStream(publicBuffer))) + { + bw.Write(new byte[] { 0x00, 0x00, 0x00 }); + bw.Write(keyType); + PutPrefixed(bw, publicParameters.Exponent, CheckIsNeddPadding(publicParameters.Exponent)); + PutPrefixed(bw, publicParameters.Modulus, CheckIsNeddPadding(publicParameters.Modulus)); + } + var publicBlob = System.Convert.ToBase64String(publicBuffer); + + var privateParameters = cryptoServiceProvider.ExportParameters(true); + byte[] privateBuffer = new byte[paddedPrefixSize + privateParameters.D.Length + paddedPrefixSize + privateParameters.P.Length + paddedPrefixSize + privateParameters.Q.Length + paddedPrefixSize + privateParameters.InverseQ.Length]; + + using (var bw = new BinaryWriter(new MemoryStream(privateBuffer))) + { + PutPrefixed(bw, privateParameters.D, true); + PutPrefixed(bw, privateParameters.P, true); + PutPrefixed(bw, privateParameters.Q, true); + PutPrefixed(bw, privateParameters.InverseQ, true); + } + var privateBlob = System.Convert.ToBase64String(privateBuffer); + + HMACSHA1 hmacsha1 = new HMACSHA1(new SHA1CryptoServiceProvider().ComputeHash(Encoding.ASCII.GetBytes("putty-private-key-file-mac-key"))); + //byte[] bytesToHash = new byte[4 + 7 + 4 + 4 + 4 + Comment.Length + 4 + publicBuffer.Length + 4 + privateBuffer.Length]; + byte[] bytesToHash = new byte[prefixSize + keyType.Length + prefixSize + encryptionType.Length + prefixSize + Comment.Length + + prefixSize + publicBuffer.Length + prefixSize + privateBuffer.Length]; + + using (var bw = new BinaryWriter(new MemoryStream(bytesToHash))) + { + PutPrefixed(bw, Encoding.ASCII.GetBytes("ssh-rsa")); + PutPrefixed(bw, Encoding.ASCII.GetBytes("none")); + PutPrefixed(bw, Encoding.ASCII.GetBytes(Comment)); + PutPrefixed(bw, publicBuffer); + PutPrefixed(bw, privateBuffer); + } + + var hash = string.Join("", hmacsha1.ComputeHash(bytesToHash).Select(x => string.Format("{0:x2}", x))); + + var sb = new StringBuilder(); + sb.AppendLine("PuTTY-User-Key-File-2: " + keyType); + sb.AppendLine("Encryption: " + encryptionType); + sb.AppendLine("Comment: " + Comment); + + var publicLines = SpliceText(publicBlob, lineLength); + sb.AppendLine("Public-Lines: " + publicLines.Length); + foreach (var line in publicLines) + { + sb.AppendLine(line); + } + + var privateLines = SpliceText(privateBlob, lineLength); + sb.AppendLine("Private-Lines: " + privateLines.Length); + foreach (var line in privateLines) + { + sb.AppendLine(line); + } + + sb.AppendLine("Private-MAC: " + hash); + + return sb.ToString(); + } + private static void PutPrefixed(BinaryWriter bw, byte[] bytes, bool addLeadingNull = false) + { + bw.Write(BitConverter.GetBytes(bytes.Length + (addLeadingNull ? 1 : 0)).Reverse().ToArray()); + if (addLeadingNull) + bw.Write(new byte[] { 0x00 }); + bw.Write(bytes); + } + + private static string[] SpliceText(string text, int lineLength) + { + return Regex.Matches(text, ".{1," + lineLength + "}").Cast<Match>().Select(m => m.Value).ToArray(); + } + private static int GetPrefixSize(byte[] bytes) + { + return CheckIsNeddPadding(bytes) ? paddedPrefixSize : prefixSize; + } + private static bool CheckIsNeddPadding(byte[] bytes) + { + // 128 == 10000000 + // This means that the number of bits can be divided by 8. + // According to the algorithm in putty, you need to add a padding. + return bytes[0] >= 128; + } + +}
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