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| 1 | +module Net |
| 2 | + module NTLM |
| 3 | + class Client::Session |
| 4 | + |
| 5 | + VERSION_MAGIC = "\x01\x00\x00\x00" |
| 6 | + TIME_OFFSET = 11644473600 |
| 7 | + MAX64 = 0xffffffffffffffff |
| 8 | + CLIENT_TO_SERVER_SIGNING = "session key to client-to-server signing key magic constant\0" |
| 9 | + SERVER_TO_CLIENT_SIGNING = "session key to server-to-client signing key magic constant\0" |
| 10 | + CLIENT_TO_SERVER_SEALING = "session key to client-to-server sealing key magic constant\0" |
| 11 | + SERVER_TO_CLIENT_SEALING = "session key to server-to-client sealing key magic constant\0" |
| 12 | + |
| 13 | + attr_reader :client, :challenge_message |
| 14 | + |
| 15 | + # @param client [Net::NTLM::Client] the client instance |
| 16 | + # @param challenge_message [Net::NTLM::Message::Type2] server message |
| 17 | + def initialize(client, challenge_message) |
| 18 | + @client = client |
| 19 | + @challenge_message = challenge_message |
| 20 | + end |
| 21 | + |
| 22 | + # Generate an NTLMv2 AUTHENTICATE_MESSAGE |
| 23 | + # @see http://msdn.microsoft.com/en-us/library/cc236643.aspx |
| 24 | + # @return [Net::NTLM::Message::Type3] |
| 25 | + def authenticate! |
| 26 | + calculate_user_session_key! |
| 27 | + type3_opts = { |
| 28 | + :lm_response => lmv2_resp, |
| 29 | + :ntlm_response => ntlmv2_resp, |
| 30 | + :domain => domain, |
| 31 | + :user => username, |
| 32 | + :workstation => workstation, |
| 33 | + :flag => (challenge_message.flag & client.flags) |
| 34 | + } |
| 35 | + t3 = Message::Type3.create type3_opts |
| 36 | + if negotiate_key_exchange? |
| 37 | + t3.enable(:session_key) |
| 38 | + rc4 = OpenSSL::Cipher::Cipher.new("rc4") |
| 39 | + rc4.encrypt |
| 40 | + rc4.key = user_session_key |
| 41 | + sk = rc4.update master_key |
| 42 | + sk << rc4.final |
| 43 | + t3.session_key = sk |
| 44 | + end |
| 45 | + t3 |
| 46 | + end |
| 47 | + |
| 48 | + def sign_message(message) |
| 49 | + seq = sequence |
| 50 | + sig = OpenSSL::HMAC.digest(OpenSSL::Digest::MD5.new, client_sign_key, "#{seq}#{message}")[0..7] |
| 51 | + if negotiate_key_exchange? |
| 52 | + sig = client_cipher.update sig |
| 53 | + sig << client_cipher.final |
| 54 | + end |
| 55 | + "#{VERSION_MAGIC}#{sig}#{seq}" |
| 56 | + end |
| 57 | + |
| 58 | + def verify_signature(signature, message) |
| 59 | + seq = signature[-4..-1] |
| 60 | + sig = OpenSSL::HMAC.digest(OpenSSL::Digest::MD5.new, server_sign_key, "#{seq}#{message}")[0..7] |
| 61 | + if negotiate_key_exchange? |
| 62 | + sig = server_cipher.update sig |
| 63 | + sig << server_cipher.final |
| 64 | + end |
| 65 | + "#{VERSION_MAGIC}#{sig}#{seq}" == signature |
| 66 | + end |
| 67 | + |
| 68 | + def seal_message(message) |
| 69 | + emessage = client_cipher.update(message) |
| 70 | + emessage + client_cipher.final |
| 71 | + end |
| 72 | + |
| 73 | + def unseal_message(emessage) |
| 74 | + message = server_cipher.update(emessage) |
| 75 | + message + server_cipher.final |
| 76 | + end |
| 77 | + |
| 78 | + |
| 79 | + private |
| 80 | + |
| 81 | + |
| 82 | + def user_session_key |
| 83 | + @user_session_key ||= nil |
| 84 | + end |
| 85 | + |
| 86 | + def master_key |
| 87 | + @master_key ||= begin |
| 88 | + if negotiate_key_exchange? |
| 89 | + OpenSSL::Cipher.new("rc4").random_key |
| 90 | + else |
| 91 | + user_session_key |
| 92 | + end |
| 93 | + end |
| 94 | + end |
| 95 | + |
| 96 | + def sequence |
| 97 | + [raw_sequence].pack("V*") |
| 98 | + end |
| 99 | + |
| 100 | + def raw_sequence |
| 101 | + if defined? @raw_sequence |
| 102 | + @raw_sequence += 1 |
| 103 | + else |
| 104 | + @raw_sequence = 0 |
| 105 | + end |
| 106 | + end |
| 107 | + |
| 108 | + def client_sign_key |
| 109 | + @client_sign_key ||= OpenSSL::Digest::MD5.digest "#{master_key}#{CLIENT_TO_SERVER_SIGNING}" |
| 110 | + end |
| 111 | + |
| 112 | + def server_sign_key |
| 113 | + @server_sign_key ||= OpenSSL::Digest::MD5.digest "#{master_key}#{SERVER_TO_CLIENT_SIGNING}" |
| 114 | + end |
| 115 | + |
| 116 | + def client_seal_key |
| 117 | + @client_seal_key ||= OpenSSL::Digest::MD5.digest "#{master_key}#{CLIENT_TO_SERVER_SEALING}" |
| 118 | + end |
| 119 | + |
| 120 | + def server_seal_key |
| 121 | + @server_seal_key ||= OpenSSL::Digest::MD5.digest "#{master_key}#{SERVER_TO_CLIENT_SEALING}" |
| 122 | + end |
| 123 | + |
| 124 | + def client_cipher |
| 125 | + @client_cipher ||= |
| 126 | + begin |
| 127 | + rc4 = OpenSSL::Cipher::Cipher.new("rc4") |
| 128 | + rc4.encrypt |
| 129 | + rc4.key = client_seal_key |
| 130 | + rc4 |
| 131 | + end |
| 132 | + end |
| 133 | + |
| 134 | + def server_cipher |
| 135 | + @server_cipher ||= |
| 136 | + begin |
| 137 | + rc4 = OpenSSL::Cipher::Cipher.new("rc4") |
| 138 | + rc4.decrypt |
| 139 | + rc4.key = server_seal_key |
| 140 | + rc4 |
| 141 | + end |
| 142 | + end |
| 143 | + |
| 144 | + def client_challenge |
| 145 | + @client_challenge ||= NTLM.pack_int64le(rand(MAX64)) |
| 146 | + end |
| 147 | + |
| 148 | + def server_challenge |
| 149 | + @server_challenge ||= challenge_message[:challenge].serialize |
| 150 | + end |
| 151 | + |
| 152 | + # epoch -> milsec from Jan 1, 1601 |
| 153 | + # @see http://support.microsoft.com/kb/188768 |
| 154 | + def timestamp |
| 155 | + @timestamp ||= 10_000_000 * (Time.now.to_i + TIME_OFFSET) |
| 156 | + end |
| 157 | + |
| 158 | + def use_oem_strings? |
| 159 | + challenge_message.has_flag? :OEM |
| 160 | + end |
| 161 | + |
| 162 | + def negotiate_key_exchange? |
| 163 | + challenge_message.has_flag? :KEY_EXCHANGE |
| 164 | + end |
| 165 | + |
| 166 | + def username |
| 167 | + oem_or_unicode_str client.username |
| 168 | + end |
| 169 | + |
| 170 | + def password |
| 171 | + oem_or_unicode_str client.password |
| 172 | + end |
| 173 | + |
| 174 | + def workstation |
| 175 | + (client.domain ? oem_or_unicode_str(client.workstation) : "") |
| 176 | + end |
| 177 | + |
| 178 | + def domain |
| 179 | + (client.domain ? oem_or_unicode_str(client.domain) : "") |
| 180 | + end |
| 181 | + |
| 182 | + def oem_or_unicode_str(str) |
| 183 | + if use_oem_strings? |
| 184 | + NTLM::EncodeUtil.decode_utf16le str |
| 185 | + else |
| 186 | + NTLM::EncodeUtil.encode_utf16le str |
| 187 | + end |
| 188 | + end |
| 189 | + |
| 190 | + def ntlmv2_hash |
| 191 | + @ntlmv2_hash ||= NTLM.ntlmv2_hash(username, password, domain, {:client_challenge => client_challenge, :unicode => !use_oem_strings?}) |
| 192 | + end |
| 193 | + |
| 194 | + def calculate_user_session_key! |
| 195 | + @user_session_key = OpenSSL::HMAC.digest(OpenSSL::Digest::MD5.new, ntlmv2_hash, nt_proof_str) |
| 196 | + end |
| 197 | + |
| 198 | + def lmv2_resp |
| 199 | + OpenSSL::HMAC.digest(OpenSSL::Digest::MD5.new, ntlmv2_hash, server_challenge + client_challenge) + client_challenge |
| 200 | + end |
| 201 | + |
| 202 | + def ntlmv2_resp |
| 203 | + nt_proof_str + blob |
| 204 | + end |
| 205 | + |
| 206 | + def nt_proof_str |
| 207 | + @nt_proof_str ||= OpenSSL::HMAC.digest(OpenSSL::Digest::MD5.new, ntlmv2_hash, server_challenge + blob) |
| 208 | + end |
| 209 | + |
| 210 | + def blob |
| 211 | + @blob ||= |
| 212 | + begin |
| 213 | + b = Blob.new |
| 214 | + b.timestamp = timestamp |
| 215 | + b.challenge = client_challenge |
| 216 | + b.target_info = challenge_message.target_info |
| 217 | + b.serialize |
| 218 | + end |
| 219 | + end |
| 220 | + |
| 221 | + end |
| 222 | + end |
| 223 | +end |
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