refactor SSH MAC

9 files changed, 190 insertions, 168 deletions

diff --git a/src/protocol/CMakeLists.txt b/src/protocol/CMakeLists.txt
index b808fb9..84d53d1 100644
--- a/src/protocol/CMakeLists.txt
+++ b/src/protocol/CMakeLists.txt
@@ -19,6 +19,8 @@ set(internal_SRCS
   internal/all_ciphers.c
   internal/ssh_evp_cipher.c
   internal/ssh_3des-ssh1.c
+  internal/ssh_mac.h
+  internal/ssh_mac.c
   internal/ssh_pubkey_crypto.h
   internal/ssh_pubkey_crypto.c
   internal/ssh_diffie-hellman.h
@@ -30,7 +32,6 @@ set(internal_SRCS
   internal/fqterm_ssh_const.h
   internal/fqterm_ssh_kex.h
   internal/fqterm_ssh2_kex.h
-  internal/fqterm_ssh_mac.h
   internal/fqterm_ssh_packet.h
   internal/fqterm_ssh1_packet.h
   internal/fqterm_ssh2_packet.h
@@ -41,7 +42,6 @@ set(internal_SRCS
   internal/fqterm_ssh_buffer.cpp
   internal/fqterm_ssh_kex.cpp
   internal/fqterm_ssh2_kex.cpp
-  internal/fqterm_ssh_mac.cpp
   internal/fqterm_ssh_packet.cpp
   internal/fqterm_ssh1_packet.cpp
   internal/fqterm_ssh2_packet.cpp
diff --git a/src/protocol/internal/fqterm_ssh2_kex.cpp b/src/protocol/internal/fqterm_ssh2_kex.cpp
index 906acca..570c29f 100644
--- a/src/protocol/internal/fqterm_ssh2_kex.cpp
+++ b/src/protocol/internal/fqterm_ssh2_kex.cpp
@@ -167,8 +167,32 @@ bool FQTermSSH2Kex::negotiateAlgorithms() {
   }
   packet_receiver_->cipher = s2c(0);
 
+  // mac algo c2s
+  size_t m_c2s_len = packet_receiver_->getInt();
+  char m_c2s[m_c2s_len+1];
+  packet_receiver_->getRawData(m_c2s, m_c2s_len);
+  m_c2s[m_c2s_len] = '\0';
+  const struct ssh_mac_t * mac_c2s = search_mac(m_c2s);
+  if (mac_c2s == NULL) {
+	  emit kexError(tr("No matching c2s MAC algorithms!"));
+	  return false;
+  }
+  packet_sender_->mac = mac_c2s->new_mac(mac_c2s);
+
+  // mac algo s2c
+  size_t m_s2c_len = packet_receiver_->getInt();
+  char m_s2c[m_s2c_len+1];
+  packet_receiver_->getRawData(m_s2c, m_s2c_len);
+  m_s2c[m_s2c_len] = '\0';
+  const struct ssh_mac_t * mac_s2c = search_mac(m_s2c);
+  if (mac_s2c == NULL) {
+	  emit kexError(tr("No matching s2c MAC algorithms!"));
+	  return false;
+  }
+  packet_receiver_->mac = mac_s2c->new_mac(mac_s2c);
+
   std::vector<char> name_lists;
-  for (int i = 4; i < 10; ++i) {
+  for (int i = 6; i < 10; ++i) {
     int name_lists_len = packet_receiver_->getInt();
     if (name_lists_len > 0) {
       name_lists.resize(name_lists_len);
@@ -191,8 +215,8 @@ bool FQTermSSH2Kex::negotiateAlgorithms() {
   packet_sender_->putString("ssh-rsa");
   packet_sender_->putString(all_ciphers_list);
   packet_sender_->putString(all_ciphers_list);
-  packet_sender_->putString("hmac-sha1");
-  packet_sender_->putString("hmac-sha1");
+  packet_sender_->putString(all_macs_list);
+  packet_sender_->putString(all_macs_list);
   packet_sender_->putString("none");
   packet_sender_->putString("none");
   packet_sender_->putString("");
@@ -330,9 +354,6 @@ bool FQTermSSH2Kex::changeKeyAlg() {
 	  memcpy(session_id_, H_, dh->digest.hashlen);
   }
 
-  packet_sender_->setMacType(FQTERM_SSH_HMAC_SHA1);
-  packet_receiver_->setMacType(FQTERM_SSH_HMAC_SHA1);
-
   // From RFC 4253 section 7.2:
   // Initial IV client to server: HASH(K || H || "A" || session_id)
   // (Here K is encoded as mpint and "A" as byte and session_id as raw
diff --git a/src/protocol/internal/fqterm_ssh2_packet.cpp b/src/protocol/internal/fqterm_ssh2_packet.cpp
index aed8b48..28c7847 100644
--- a/src/protocol/internal/fqterm_ssh2_packet.cpp
+++ b/src/protocol/internal/fqterm_ssh2_packet.cpp
@@ -62,9 +62,8 @@ void FQTermSSH2PacketSender::makePacket() {
 
   // 2. renew the output buffer.
   int total_len = non_padding_len + padding_len;
-  if (is_mac_) {
-    total_len += mac_->digestSize();
-  }
+  if (is_mac_)
+    total_len += mac->dgstSize;
 
   delete output_buffer_;
   output_buffer_ = new FQTermSSHBuffer(total_len);
@@ -95,8 +94,8 @@ void FQTermSSH2PacketSender::makePacket() {
     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]);
+    std::vector<u_char> digest(mac->dgstSize);
+    mac->getmac(mac, buffer.data(), buffer.len(), &digest[0]);
 
     FQ_TRACE("ssh2packet", 9) << "Making packets...";
     FQ_TRACE("ssh2packet", 9) << "Append MAC with sequence_no_" << sequence_no_; 
@@ -121,7 +120,7 @@ void FQTermSSH2PacketSender::makePacket() {
     // with the given algorithm.
 
     u_char *data = output_buffer_->data();
-    int len = output_buffer_->len() - mac_->digestSize();
+    int len = output_buffer_->len() - mac->dgstSize;
 
     FQ_TRACE("ssh2packet", 9) << "An packet (without MAC) to be encrypted:" 
                               << len << " bytes:\n" 
@@ -174,7 +173,7 @@ void FQTermSSH2PacketReceiver::parseData(FQTermSSHBuffer *input) {
       return ;
     }
 
-    int expected_input_len = 4 + packet_len + (is_mac_ ? mac_->digestSize() : 0);
+    int expected_input_len = 4 + packet_len + (is_mac_ ? mac->dgstSize : 0);
 
     if (input->len()  < (long)expected_input_len) {
       FQ_TRACE("ssh2packet", 3)
@@ -189,15 +188,15 @@ void FQTermSSH2PacketReceiver::parseData(FQTermSSHBuffer *input) {
     if (is_decrypt_) {
       // decrypte blocks left.
       unsigned char *tmp = input->data() + cipher->blkSize;
-      int left_len = expected_input_len - cipher->blkSize - mac_->digestSize();
+      int left_len = expected_input_len - cipher->blkSize - mac->dgstSize;
       FQ_VERIFY(cipher->crypt(cipher, tmp, tmp, left_len)==1);
     }
 
     // 3. check MAC
     if (is_mac_) {
-      int digest_len = mac_->digestSize();
+      int digest_len = mac->dgstSize;
       std::vector<u_char> digest(digest_len);
-      mac_->getDigest(input->data(), expected_input_len - digest_len, &digest[0]);
+      mac->getmac(mac, input->data(), expected_input_len - digest_len, &digest[0]);
 
       u_char *received_digest = input->data() + expected_input_len - digest_len;
 
@@ -213,9 +212,8 @@ void FQTermSSH2PacketReceiver::parseData(FQTermSSHBuffer *input) {
     std::vector<u_char> data(packet_len);
 
     input->getRawData((char*)&data[0], packet_len);
-    if (is_mac_) {
-      input->consume(mac_->digestSize());
-    }
+    if (is_mac_)
+      input->consume(mac->dgstSize);
 
     int padding_len = data[0];
 
diff --git a/src/protocol/internal/fqterm_ssh_mac.cpp b/src/protocol/internal/fqterm_ssh_mac.cpp
deleted file mode 100644
index e2d345f..0000000
--- a/src/protocol/internal/fqterm_ssh_mac.cpp
+++ /dev/null
@@ -1,53 +0,0 @@
-/***************************************************************************
- *   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 <openssl/evp.h>
-#include <openssl/hmac.h>
-
-#include "fqterm_trace.h"
-#include "fqterm_ssh_mac.h"
-#include "fqterm_ssh_packet.h"
-
-namespace FQTerm {
-
-void FQTermSSHSHA1::setKey(const unsigned char *key) {
-  memcpy(key_, key, keySize());
-}
-
-int FQTermSSHSHA1::keySize() const {
-  return SHA_DIGEST_LENGTH;
-}
-
-int FQTermSSHSHA1::digestSize() const {
-  return SHA_DIGEST_LENGTH;
-}
-
-void FQTermSSHSHA1::getDigest(const unsigned char *data, int len, unsigned char *digest) const {
-  unsigned int tmp;
-  HMAC(EVP_sha1(), key_, SHA_DIGEST_LENGTH, data, len, digest, &tmp);
-
-  FQ_TRACE("SHA1", 9) << "Key: \n" << dumpHexString << std::string((char *)key_, SHA_DIGEST_LENGTH);
-  FQ_TRACE("SHA1", 9) << "data len:" << len;
-  FQ_TRACE("SHA1", 9) << "data:\n" << dumpHexString << std::string((char *)data, len);
-  FQ_TRACE("SHA1", 9) << "digest len:" << tmp;
-  FQ_TRACE("SHA1", 9) << "digest:\n" << dumpHexString << std::string((char *)digest, tmp);
-}
-
-}  // namespace FQTerm
diff --git a/src/protocol/internal/fqterm_ssh_mac.h b/src/protocol/internal/fqterm_ssh_mac.h
deleted file mode 100644
index 545909c..0000000
--- a/src/protocol/internal/fqterm_ssh_mac.h
+++ /dev/null
@@ -1,54 +0,0 @@
-/***************************************************************************
- *   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.               *
- ***************************************************************************/
-
-#ifndef FQTERM_SSH_MAC_H
-#define FQTERM_SSH_MAC_H
-
-#include <openssl/sha.h>
-
-namespace FQTerm {
-
-class FQTermSSHMac {
-public:
-  FQTermSSHMac() {}
-  virtual ~FQTermSSHMac() {}
-  virtual void setKey(const unsigned char *key) = 0;
-  virtual int keySize() const = 0;
-  virtual int digestSize() const = 0;
-  virtual void getDigest(const unsigned char *data, int len, unsigned char *digest) const = 0;
-};
-
-const int FQTERM_SSH_MAC_NONE = 0;
-const int FQTERM_SSH_HMAC_SHA1 = 1;
-
-class FQTermSSHSHA1: public FQTermSSHMac {
-  unsigned char key_[SHA_DIGEST_LENGTH];
-
-public:
-  virtual void setKey(const unsigned char *key);
-  virtual int keySize() const;
-  virtual int digestSize() const;
-  virtual void getDigest(const unsigned char *data, int len, unsigned char *digest) const;
-};
-
-
-}  // namespace FQTerm
-
-#endif  // FQTERM_SSH_MAC_H
diff --git a/src/protocol/internal/fqterm_ssh_packet.cpp b/src/protocol/internal/fqterm_ssh_packet.cpp
index 402d1b8..d9a8f89 100644
--- a/src/protocol/internal/fqterm_ssh_packet.cpp
+++ b/src/protocol/internal/fqterm_ssh_packet.cpp
@@ -41,8 +41,7 @@ FQTermSSHPacketSender::FQTermSSHPacketSender() {
   cipher = NULL;
 
   is_mac_ = false;
-  mac_type_ = FQTERM_SSH_MAC_NONE;
-  mac_ = NULL;
+  mac = NULL;
 
   is_compressed_ = false;
 
@@ -54,6 +53,8 @@ FQTermSSHPacketSender::~FQTermSSHPacketSender() {
 	delete output_buffer_;
 	if (cipher)
 		cipher->cleanup(cipher);
+        if (mac)
+		mac->cleanup(mac);
 }
 
 void FQTermSSHPacketSender::putRawData(const char *data, int len) {
@@ -104,22 +105,9 @@ void FQTermSSHPacketSender::resetEncryption() {
   is_encrypt_ = false;
 }
 
-void FQTermSSHPacketSender::setMacType(int macType) {
-  mac_type_ = macType;
-
-  delete mac_;
-  mac_ = NULL;
-
-  switch (mac_type_) {
-    case FQTERM_SSH_HMAC_SHA1:
-      mac_ = new FQTermSSHSHA1;
-      break;
-  }
-}
-
 void FQTermSSHPacketSender::startMac(const u_char *key) {
   is_mac_ = true;
-  mac_->setKey(key);
+  memcpy(mac->key, key, mac->keySize);
 }
 
 void FQTermSSHPacketSender::resetMac() {
@@ -138,8 +126,7 @@ FQTermSSHPacketReceiver::FQTermSSHPacketReceiver() {
   cipher = NULL;
 
   is_mac_ = false;
-  mac_type_ = FQTERM_SSH_MAC_NONE;
-  mac_ = NULL;
+  mac = NULL;
 
   is_compressed_ = false;
 
@@ -151,6 +138,8 @@ FQTermSSHPacketReceiver::~FQTermSSHPacketReceiver()
 	delete buffer_;
 	if (cipher)
 		cipher->cleanup(cipher);
+        if (mac)
+		mac->cleanup(mac);
 }
 
 void FQTermSSHPacketReceiver::getRawData(char *data, int length) {
@@ -195,21 +184,9 @@ void FQTermSSHPacketReceiver::resetEncryption() {
   is_decrypt_ = false;
 }
 
-void FQTermSSHPacketReceiver::setMacType(int macType) {
-  mac_type_ = macType;
-  delete mac_;
-  mac_ = NULL;
-
-  switch (mac_type_) {
-    case FQTERM_SSH_HMAC_SHA1:
-      mac_ = new FQTermSSHSHA1;
-      break;
-  }
-}
-
 void FQTermSSHPacketReceiver::startMac(const u_char *key) {
   is_mac_ = true;
-  mac_->setKey(key);
+  memcpy(mac->key, key, mac->keySize);
 }
 
 void FQTermSSHPacketReceiver::resetMac() {
diff --git a/src/protocol/internal/fqterm_ssh_packet.h b/src/protocol/internal/fqterm_ssh_packet.h
index 705a11b..7caa663 100644
--- a/src/protocol/internal/fqterm_ssh_packet.h
+++ b/src/protocol/internal/fqterm_ssh_packet.h
@@ -27,7 +27,7 @@
 
 #include "fqterm_ssh_types.h"
 #include "fqterm_ssh_buffer.h"
-#include "fqterm_ssh_mac.h"
+#include "ssh_mac.h"
 #include "fqterm_serialization.h"
 #include "ssh_cipher.h"
 
@@ -39,6 +39,7 @@ class FQTermSSHPacketSender: public QObject {
   FQTermSSHBuffer *output_buffer_;
   FQTermSSHBuffer *buffer_;
   ssh_cipher_t *cipher;
+  ssh_mac_t *mac;
 
   FQTermSSHPacketSender();
   virtual ~FQTermSSHPacketSender();
@@ -54,13 +55,12 @@ class FQTermSSHPacketSender: public QObject {
 
   virtual int getIVSize() const { return cipher->IVSize;}
   virtual int getKeySize() const { return cipher->keySize;}
-  int getMacKeySize() const { return mac_->keySize();}
+  int getMacKeySize() const { return mac->keySize;}
 
  public slots:
   void startEncryption(const u_char *key, const u_char *IV = NULL);
   void resetEncryption();
 
-  void setMacType(int macType);
   void startMac(const u_char *sessionkey);
   void resetMac();
 
@@ -74,8 +74,6 @@ class FQTermSSHPacketSender: public QObject {
   int cipher_type_;
 
   bool is_mac_;
-  int mac_type_;
-  FQTermSSHMac *mac_;
 
   bool is_compressed_;
 
@@ -89,6 +87,7 @@ class FQTermSSHPacketReceiver: public QObject {
  public:
   FQTermSSHBuffer *buffer_;
   ssh_cipher_t *cipher;
+  ssh_mac_t *mac;
 
   FQTermSSHPacketReceiver();
   virtual ~FQTermSSHPacketReceiver();
@@ -108,14 +107,13 @@ class FQTermSSHPacketReceiver: public QObject {
   virtual int packetDataLen() const { return real_data_len_;}
   virtual int getIVSize() const { return cipher->IVSize;}
   virtual int getKeySize() const { return cipher->keySize;}
-  int getMacKeySize() const { return mac_->keySize();}
+  int getMacKeySize() const { return mac->keySize;}
 
   virtual void parseData(FQTermSSHBuffer *input) = 0;
  public slots:
   void startEncryption(const u_char *key, const u_char *IV = NULL);
   void resetEncryption();
 
-  void setMacType(int macType);
   void startMac(const u_char *sessionkey);
   void resetMac();
 
@@ -130,8 +128,6 @@ class FQTermSSHPacketReceiver: public QObject {
   int cipher_type_;
 
   bool is_mac_;
-  int mac_type_;
-  FQTermSSHMac *mac_;
 
   bool is_compressed_;
 
diff --git a/src/protocol/internal/ssh_mac.c b/src/protocol/internal/ssh_mac.c
new file mode 100644
index 0000000..2062cff
--- /dev/null
+++ b/src/protocol/internal/ssh_mac.c
@@ -0,0 +1,82 @@
+/*
+ * ssh_mac.c: the MAC algorithms used in SSH
+ * Copyright (C) 2018  Iru Cai <mytbk920423@gmail.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#include "ssh_mac.h"
+#include "ssh_crypto_common.h"
+#include <stdlib.h>
+#include <openssl/evp.h>
+#include <openssl/hmac.h>
+
+static struct ssh_mac_t *new_evp_mac(const struct ssh_mac_t *t)
+{
+	struct ssh_mac_t *m = (struct ssh_mac_t *)malloc(sizeof(struct ssh_mac_t));
+	const EVP_MD *evp_md = ((const EVP_MD *(*)(void))(t->priv))();
+	*m = *t;
+	m->priv = evp_md;
+	return m;
+}
+
+static void free_evp_mac(struct ssh_mac_t *m)
+{
+	free(m);
+}
+
+static void get_evp_digest(SSH_MAC *my, const unsigned char *d, int len, unsigned char *dgst)
+{
+	unsigned int tmp;
+	HMAC((const EVP_MD *)(my->priv), my->key, my->keySize, d, len, dgst, &tmp);
+}
+
+/* RFC 6668 */
+struct ssh_mac_t hmac_sha2_256 = {
+	.name = "hmac-sha2-256",
+	.priv = (void*)EVP_sha256,
+	.new_mac = new_evp_mac,
+	.cleanup = free_evp_mac,
+	.getmac = get_evp_digest,
+	.dgstSize = 32,
+	.keySize = 32
+};
+
+struct ssh_mac_t hmac_sha1 = {
+	.name = "hmac-sha1",
+	.priv = (void*)EVP_sha1,
+	.new_mac = new_evp_mac,
+	.cleanup = free_evp_mac,
+	.getmac = get_evp_digest,
+	.dgstSize = 20,
+	.keySize = 20
+};
+
+static name_list all_macs = {
+	{ "hmac-sha2-256", &hmac_sha2_256 },
+	{ "hmac-sha1", &hmac_sha1 },
+	{ NULL, NULL }
+};
+
+const struct ssh_mac_t * search_mac(const char *s)
+{
+	int i = search_name(all_macs, s);
+	if (i!=-1)
+		return all_macs[i].f;
+	else
+		return NULL;
+}
+
+const char all_macs_list[] = "hmac-sha2-256,hmac-sha1";
diff --git a/src/protocol/internal/ssh_mac.h b/src/protocol/internal/ssh_mac.h
new file mode 100644
index 0000000..507a9cd
--- /dev/null
+++ b/src/protocol/internal/ssh_mac.h
@@ -0,0 +1,55 @@
+/*
+ * ssh_mac.h: the MAC algorithms used in SSH
+ * Copyright (C) 2018  Iru Cai <mytbk920423@gmail.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#ifndef SSH_MAC_H
+#define SSH_MAC_H
+
+#include <stdlib.h>
+#include <stdint.h>
+#include <openssl/evp.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+	typedef struct ssh_mac_t SSH_MAC;
+	typedef SSH_MAC* (*create_t)(const SSH_MAC*);
+	typedef void (*mac_cleanup_t)(SSH_MAC*);
+	typedef void (*mac_t)(SSH_MAC*, const unsigned char*, int, unsigned char*);
+
+	struct ssh_mac_t
+	{
+		const char *name;
+		void *priv;
+		create_t new_mac;
+		mac_cleanup_t cleanup;
+		mac_t getmac;
+		unsigned char key[32];
+		size_t dgstSize;
+		size_t keySize;
+	};
+
+	const struct ssh_mac_t *search_mac(const char *s);
+	extern const char all_macs_list[];
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif