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Diffstat (limited to 'src/protocol/internal/fqterm_ssh2_packet.cpp')
-rw-r--r--src/protocol/internal/fqterm_ssh2_packet.cpp267
1 files changed, 267 insertions, 0 deletions
diff --git a/src/protocol/internal/fqterm_ssh2_packet.cpp b/src/protocol/internal/fqterm_ssh2_packet.cpp
new file mode 100644
index 0000000..d3094d3
--- /dev/null
+++ b/src/protocol/internal/fqterm_ssh2_packet.cpp
@@ -0,0 +1,267 @@
+/***************************************************************************
+ * fqterm, a terminal emulator for both BBS and *nix. *
+ * Copyright (C) 2008 fqterm development group. *
+ * *
+ * This program is free software; you can redistribute it and/or modify *
+ * it under the terms of the GNU General Public License as published by *
+ * the Free Software Foundation; either version 2 of the License, or *
+ * (at your option) any later version. *
+ * *
+ * This program is distributed in the hope that it will be useful, *
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of *
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
+ * GNU General Public License for more details. *
+ * *
+ * You should have received a copy of the GNU General Public License *
+ * along with this program; if not, write to the *
+ * Free Software Foundation, Inc., *
+ * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. *
+ ***************************************************************************/
+
+#include "fqterm_trace.h"
+#include "fqterm_ssh_buffer.h"
+#include "fqterm_ssh2_packet.h"
+#include "fqterm_ssh_des.h"
+
+#include "fqterm_serialization.h"
+#include "crc32.h"
+
+namespace FQTerm {
+//==============================================================================
+//FQTermSSH2PacketSender
+//==============================================================================
+// SSH2 Packet Structure:
+// uint32 packet_length
+// byte padding_length
+// byte[n1] payload; n1 = packet_length - padding_length - 1
+// byte[n2] random padding; n2 = padding_length
+// byte[m] mac (Message Authentication Code - MAC); m = mac_length
+//==============================================================================
+
+void FQTermSSH2PacketSender::makePacket() {
+ FQ_TRACE("ssh2packet", 9) << "----------------------------Send "
+ << (is_encrypt_ ? "Encrypted": "plain")
+ << " Packet---->>>>>>>";
+
+ // 0. compress
+ if (is_compressed_) {
+ FQ_VERIFY(false);
+ }
+
+ // 1. compute the padding length for padding.
+ int non_padding_len = 4 + 1 + buffer_->len();
+
+ int padding_block_len = 8;
+ if (is_encrypt_ && cipher_->blockSize() > padding_block_len) {
+ padding_block_len = cipher_->blockSize();
+ }
+
+ int padding_len = padding_block_len - (non_padding_len % padding_block_len);
+ if (padding_len < 4) {
+ padding_len += padding_block_len;
+ }
+
+ // 2. renew the output buffer.
+ int total_len = non_padding_len + padding_len;
+ if (is_mac_) {
+ total_len += mac_->digestSize();
+ }
+
+ delete output_buffer_;
+ output_buffer_ = new FQTermSSHBuffer(total_len);
+
+ // 3. Fill the output buffer.
+ int packet_len = 1 + buffer_->len() + padding_len;
+
+ output_buffer_->putInt(packet_len);
+ output_buffer_->putByte(padding_len);
+ output_buffer_->putRawData((const char*)buffer_->data(), buffer_->len());
+
+ u_int32_t rand_val = 0;
+ for (int i = 0; i < padding_len; i++) {
+ if (i % 4 == 0) {
+ rand_val = rand(); // FIXME: rand() doesn't range from 0 to 2^32.
+ }
+ output_buffer_->putByte(rand_val & 0xff);
+ rand_val >>= 8;
+ }
+
+ // 4. Add MAC on the entire unencrypted packet,
+ // including two length fields, 'payload' and 'random padding'.
+ if (is_mac_) {
+ const unsigned char *packet = output_buffer_->data();
+ int len = output_buffer_->len();
+
+ FQTermSSHBuffer buffer(4 + len);
+ buffer.putInt(sequence_no_);
+ buffer.putRawData((const char *)packet, len);
+
+ std::vector<u_char> digest(mac_->digestSize());
+ mac_->getDigest(buffer.data(), buffer.len(), &digest[0]);
+
+ FQ_TRACE("ssh2packet", 9) << "Making packets...";
+ FQ_TRACE("ssh2packet", 9) << "Append MAC with sequence_no_" << sequence_no_;
+ FQ_TRACE("ssh2packet", 9) << "Compute MAC with "
+ << buffer.len() << " bytes data:\n"
+ << dumpHexString << std::string((char *)buffer.data(), buffer.len());
+ FQ_TRACE("ssh2packet", 9) << "MAC data "
+ << digest.size() << " bytes:\n"
+ << dumpHexString << std::string((const char *)&digest[0], digest.size());
+
+ output_buffer_->putRawData((const char *)&digest[0], digest.size());
+ }
+
+ if (is_compressed_) {
+ FQ_VERIFY(false);
+ }
+
+ if (is_encrypt_) {
+ // as RFC 4253:
+ // When encryption is in effect, the packet length, padding
+ // length, payload, and padding fields of each packet MUST be encrypted
+ // with the given algorithm.
+
+ u_char *data = output_buffer_->data();
+ int len = output_buffer_->len() - mac_->digestSize();
+
+ FQ_TRACE("ssh2packet", 9) << "An packet (without MAC) to be encrypted:"
+ << len << " bytes:\n"
+ << dumpHexString << std::string((const char *)data, len);
+
+ cipher_->encrypt(data, data, len);
+
+ FQ_TRACE("ssh2packet", 9) << "An encrypted packet (without MAC) made:"
+ << len << " bytes:\n"
+ << dumpHexString << std::string((const char *)data, len);
+ }
+
+ ++sequence_no_;
+}
+
+void FQTermSSH2PacketSender::setEncryptionType(int cipherType) {
+ cipher_type_ = cipherType;
+
+ delete cipher_;
+ cipher_ = NULL;
+
+ switch (cipher_type_) {
+ case SSH_CIPHER_3DES:
+ cipher_ = new FQTermSSH2TripleDESCBC;
+ break;
+ }
+}
+
+
+//==============================================================================
+//FQTermSSH2PacketReceiver
+//==============================================================================
+void FQTermSSH2PacketReceiver::parseData(FQTermSSHBuffer *input) {
+ FQ_TRACE("ssh2packet", 9) << "----------------------------Receive "
+ << (is_decrypt_ ? "Encrypted": "plain")
+ << " Packet----<<<<<<<";
+ while (input->len() > 0) {
+ // 1. Check the ssh packet
+ if (input->len() < 16
+ || (is_decrypt_ && input->len() < cipher_->blockSize())
+ || input->len() < last_expected_input_length_
+ ) {
+ FQ_TRACE("ssh2packet", 3)
+ << "Got an incomplete packet. Wait for more data.";
+ return ;
+ }
+
+ if (last_expected_input_length_ == 0) {
+ if (is_decrypt_) {
+ // decrypte the first block to get the packet_length field.
+ cipher_->decrypt(input->data(), input->data(), cipher_->blockSize());
+ }
+ } else {
+ // last_expected_input_length_ != 0
+ // indicates an incomplete ssh2 packet received last time,
+ // the first block of data is already decrypted at that time,
+ // so it must not be decrypted again.
+ }
+
+ int packet_len = ntohu32(input->data());
+
+ if (packet_len > SSH_BUFFER_MAX) {
+ emit packetError(tr("parseData: packet too big"));
+ return ;
+ }
+
+ int expected_input_len = 4 + packet_len + (is_mac_ ? mac_->digestSize() : 0);
+
+ if (input->len() < (long)expected_input_len) {
+ FQ_TRACE("ssh2packet", 3)
+ << "The packet is too small. Wait for more data.";
+ last_expected_input_length_ = expected_input_len;
+ return ;
+ } else {
+ last_expected_input_length_ = 0;
+ }
+
+ // 2. decrypte data.
+ if (is_decrypt_) {
+ // decrypte blocks left.
+ unsigned char *tmp = input->data() + cipher_->blockSize();
+ int left_len = expected_input_len - cipher_->blockSize() - mac_->digestSize();
+ cipher_->decrypt(tmp, tmp, left_len);
+ }
+
+ // 3. check MAC
+ if (is_mac_) {
+ int digest_len = mac_->digestSize();
+ std::vector<u_char> digest(digest_len);
+ mac_->getDigest(input->data(), expected_input_len - digest_len, &digest[0]);
+
+ u_char *received_digest = input->data() + expected_input_len - digest_len;
+
+ if (memcmp(&digest[0], received_digest, digest_len) == 0) {
+ FQ_TRACE("ssh2packet", 0) << "incorrect MAC.";
+ return ;
+ }
+ }
+
+ // 4. get every field of the ssh packet.
+ packet_len = input->getInt();
+
+ std::vector<u_char> data(packet_len);
+
+ input->getRawData((char*)&data[0], packet_len);
+ if (is_mac_) {
+ input->consume(mac_->digestSize());
+ }
+
+ int padding_len = data[0];
+
+ real_data_len_ = packet_len - 1 - padding_len;
+
+ buffer_->clear();
+ buffer_->putRawData((char*)&data[0] + 1, real_data_len_);
+
+ FQ_TRACE("ssh2packet", 9) << "Receive " << real_data_len_ << " bytes payload:\n"
+ << dumpHexString << std::string((char *)&data[0] + 1, real_data_len_);
+
+ // 5. notify others a ssh packet is parsed successfully.
+ packet_type_ = buffer_->getByte();
+ real_data_len_ -= 1;
+ emit packetAvaliable(packet_type_);
+
+ ++sequence_no_;
+ }
+}
+
+void FQTermSSH2PacketReceiver::setEncryptionType(int cipherType) {
+ cipher_type_ = cipherType;
+
+ delete cipher_;
+ cipher_ = NULL;
+
+ switch (cipher_type_) {
+ case SSH_CIPHER_3DES:
+ cipher_ = new FQTermSSH2TripleDESCBC;
+ break;
+ }
+}
+
+} // namespace FQTerm
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