| | | 1 | | using Renci.SshNet.Messages.Transport; |
| | | 2 | | |
| | | 3 | | namespace Renci.SshNet.Security |
| | | 4 | | { |
| | | 5 | | /// <summary> |
| | | 6 | | /// Base class for "diffie-hellman-group-exchange" algorithms. |
| | | 7 | | /// </summary> |
| | | 8 | | internal abstract class KeyExchangeDiffieHellmanGroupExchangeShaBase : KeyExchangeDiffieHellman |
| | | 9 | | { |
| | | 10 | | private const int MinimumGroupSize = 1024; |
| | | 11 | | private const int PreferredGroupSize = 1024; |
| | | 12 | | private const int MaximumProupSize = 8192; |
| | | 13 | | |
| | | 14 | | /// <summary> |
| | | 15 | | /// Calculates key exchange hash value. |
| | | 16 | | /// </summary> |
| | | 17 | | /// <returns> |
| | | 18 | | /// Key exchange hash. |
| | | 19 | | /// </returns> |
| | | 20 | | protected override byte[] CalculateHash() |
| | 12 | 21 | | { |
| | 12 | 22 | | var groupExchangeHashData = new GroupExchangeHashData |
| | 12 | 23 | | { |
| | 12 | 24 | | ClientVersion = Session.ClientVersion, |
| | 12 | 25 | | ServerVersion = Session.ServerVersion, |
| | 12 | 26 | | ClientPayload = _clientPayload, |
| | 12 | 27 | | ServerPayload = _serverPayload, |
| | 12 | 28 | | HostKey = _hostKey, |
| | 12 | 29 | | MinimumGroupSize = MinimumGroupSize, |
| | 12 | 30 | | PreferredGroupSize = PreferredGroupSize, |
| | 12 | 31 | | MaximumGroupSize = MaximumProupSize, |
| | 12 | 32 | | Prime = _prime, |
| | 12 | 33 | | SubGroup = _group, |
| | 12 | 34 | | ClientExchangeValue = _clientExchangeValue, |
| | 12 | 35 | | ServerExchangeValue = _serverExchangeValue, |
| | 12 | 36 | | SharedKey = SharedKey, |
| | 12 | 37 | | }; |
| | | 38 | | |
| | 12 | 39 | | return Hash(groupExchangeHashData.GetBytes()); |
| | 12 | 40 | | } |
| | | 41 | | |
| | | 42 | | /// <summary> |
| | | 43 | | /// Starts key exchange algorithm. |
| | | 44 | | /// </summary> |
| | | 45 | | /// <param name="session">The session.</param> |
| | | 46 | | /// <param name="message">Key exchange init message.</param> |
| | | 47 | | public override void Start(Session session, KeyExchangeInitMessage message) |
| | 6 | 48 | | { |
| | 6 | 49 | | base.Start(session, message); |
| | | 50 | | |
| | | 51 | | // Register SSH_MSG_KEX_DH_GEX_GROUP message |
| | 6 | 52 | | Session.RegisterMessage("SSH_MSG_KEX_DH_GEX_GROUP"); |
| | | 53 | | |
| | | 54 | | // Subscribe to KeyExchangeDhGroupExchangeGroupReceived events |
| | 6 | 55 | | Session.KeyExchangeDhGroupExchangeGroupReceived += Session_KeyExchangeDhGroupExchangeGroupReceived; |
| | | 56 | | |
| | | 57 | | // 1. client sends SSH_MSG_KEY_DH_GEX_REQUEST |
| | 6 | 58 | | SendMessage(new KeyExchangeDhGroupExchangeRequest(MinimumGroupSize, PreferredGroupSize, MaximumProupSize)); |
| | 6 | 59 | | } |
| | | 60 | | |
| | | 61 | | /// <summary> |
| | | 62 | | /// Finishes key exchange algorithm. |
| | | 63 | | /// </summary> |
| | | 64 | | public override void Finish() |
| | 6 | 65 | | { |
| | 6 | 66 | | base.Finish(); |
| | | 67 | | |
| | 6 | 68 | | Session.KeyExchangeDhGroupExchangeGroupReceived -= Session_KeyExchangeDhGroupExchangeGroupReceived; |
| | 6 | 69 | | Session.KeyExchangeDhGroupExchangeReplyReceived -= Session_KeyExchangeDhGroupExchangeReplyReceived; |
| | 6 | 70 | | } |
| | | 71 | | |
| | | 72 | | private void Session_KeyExchangeDhGroupExchangeGroupReceived(object sender, MessageEventArgs<KeyExchangeDhGroupE |
| | 6 | 73 | | { |
| | | 74 | | // 2. server sends SSH_MSG_KEX_DH_GEX_GROUP |
| | 6 | 75 | | var groupMessage = e.Message; |
| | | 76 | | |
| | | 77 | | // Unregister SSH_MSG_KEX_DH_GEX_GROUP message once received |
| | 6 | 78 | | Session.UnRegisterMessage("SSH_MSG_KEX_DH_GEX_GROUP"); |
| | | 79 | | |
| | | 80 | | // Unsubscribe from KeyExchangeDhGroupExchangeGroupReceived events |
| | 6 | 81 | | Session.KeyExchangeDhGroupExchangeGroupReceived -= Session_KeyExchangeDhGroupExchangeGroupReceived; |
| | | 82 | | |
| | | 83 | | // Register in order to be able to receive SSH_MSG_KEX_DH_GEX_REPLY message |
| | 6 | 84 | | Session.RegisterMessage("SSH_MSG_KEX_DH_GEX_REPLY"); |
| | | 85 | | |
| | | 86 | | // Subscribe to KeyExchangeDhGroupExchangeReplyReceived events |
| | 6 | 87 | | Session.KeyExchangeDhGroupExchangeReplyReceived += Session_KeyExchangeDhGroupExchangeReplyReceived; |
| | | 88 | | |
| | 6 | 89 | | _prime = groupMessage.SafePrime; |
| | 6 | 90 | | _group = groupMessage.SubGroup; |
| | | 91 | | |
| | 6 | 92 | | PopulateClientExchangeValue(); |
| | | 93 | | |
| | | 94 | | // 3. client sends SSH_MSG_KEX_DH_GEX_INIT |
| | 6 | 95 | | SendMessage(new KeyExchangeDhGroupExchangeInit(_clientExchangeValue)); |
| | 6 | 96 | | } |
| | | 97 | | |
| | | 98 | | private void Session_KeyExchangeDhGroupExchangeReplyReceived(object sender, MessageEventArgs<KeyExchangeDhGroupE |
| | 6 | 99 | | { |
| | | 100 | | // 4. server sends SSH_MSG_KEX_DH_GEX_REPLY |
| | 6 | 101 | | var replyMessage = e.Message; |
| | | 102 | | |
| | | 103 | | // Unregister SSH_MSG_KEX_DH_GEX_REPLY message once received |
| | 6 | 104 | | Session.UnRegisterMessage("SSH_MSG_KEX_DH_GEX_REPLY"); |
| | | 105 | | |
| | | 106 | | // Unsubscribe from KeyExchangeDhGroupExchangeReplyReceived events |
| | 6 | 107 | | Session.KeyExchangeDhGroupExchangeReplyReceived -= Session_KeyExchangeDhGroupExchangeReplyReceived; |
| | | 108 | | |
| | 6 | 109 | | HandleServerDhReply(replyMessage.HostKey, replyMessage.F, replyMessage.Signature); |
| | | 110 | | |
| | | 111 | | // When SSH_MSG_KEX_DH_GEX_REPLY received key exchange is completed |
| | 6 | 112 | | Finish(); |
| | 6 | 113 | | } |
| | | 114 | | } |
| | | 115 | | } |