| 25,8 → 25,8 |
|---|
| ;---------------------------------------------- |
| ; >> Send Diffie-Hellman Group Exchange Request |
| |
| DEBUGF 1, "Sending GEX\n" |
| stdcall ssh_send_packet, [socketnum], ssh_gex_req, ssh_gex_req.length, 0 |
| DEBUGF 2, "Sending GEX\n" |
| stdcall ssh_send_packet, con, ssh_gex_req, ssh_gex_req.length, 0 |
| cmp eax, -1 |
| je .socket_err |
| |
| 33,31 → 33,31 |
|---|
| ;--------------------------------------------- |
| ; << Parse Diffie-Hellman Group Exchange Group |
| |
| stdcall ssh_recv_packet, [socketnum], rx_buffer, BUFFERSIZE, 0 |
| stdcall ssh_recv_packet, con, 0 |
| cmp eax, -1 |
| je .socket_err |
| |
| cmp [rx_buffer+ssh_header.message_code], SSH_MSG_KEX_DH_GEX_GROUP |
| cmp [con.rx_buffer.message_code], SSH_MSG_KEX_DH_GEX_GROUP |
| jne proto_err |
| DEBUGF 1, "Received GEX group\n" |
| DEBUGF 2, "Received GEX group\n" |
| |
| mov esi, rx_buffer+sizeof.ssh_header |
| mov edi, dh_p |
| mov esi, con.rx_buffer+sizeof.ssh_packet_header |
| mov edi, con.dh_p |
| DEBUGF 1, "DH modulus (p): " |
| call mpint_to_little_endian |
| stdcall mpint_print, dh_p |
| stdcall mpint_print, con.dh_p |
| |
| DEBUGF 1, "DH base (g): " |
| mov edi, dh_g |
| mov edi, con.dh_g |
| call mpint_to_little_endian |
| stdcall mpint_print, dh_g |
| stdcall mpint_print, con.dh_g |
| |
| ;------------------------------------------- |
| ; >> Send Diffie-Hellman Group Exchange Init |
| |
| ; generate a random number x, where 1 < x < (p-1)/2 |
| mov edi, dh_x+4 |
| mov [dh_x], DH_PRIVATE_KEY_SIZE/8 |
| mov edi, con.dh_x+4 |
| mov [con.dh_x], DH_PRIVATE_KEY_SIZE/8 |
| mov ecx, DH_PRIVATE_KEY_SIZE/8/4 |
| @@: |
| push ecx |
| 71,7 → 71,7 |
|---|
| shl eax, 1 |
| jnc @f |
| mov byte[edi], 0 |
| inc dword[dh_x] |
| inc dword[con.dh_x] |
| @@: |
| |
| ; Fill remaining bytes with zeros ; TO BE REMOVED ? |
| 82,28 → 82,28 |
|---|
| end if |
| |
| DEBUGF 1, "DH x: " |
| stdcall mpint_length, dh_x;;;;;;;;;;;;; |
| stdcall mpint_print, dh_x |
| stdcall mpint_length, con.dh_x;;;;;;;;;;;;; |
| stdcall mpint_print, con.dh_x |
| |
| ; Compute e = g^x mod p |
| stdcall mpint_modexp, dh_e, dh_g, dh_x, dh_p |
| stdcall mpint_length, dh_e |
| stdcall mpint_modexp, con.dh_e, con.dh_g, con.dh_x, con.dh_p |
| stdcall mpint_length, con.dh_e |
| |
| DEBUGF 1, "DH e: " |
| stdcall mpint_print, dh_e |
| stdcall mpint_print, con.dh_e |
| |
| ; Create group exchange init packet |
| mov edi, tx_buffer+ssh_header.message_code |
| mov edi, con.tx_buffer.message_code |
| mov al, SSH_MSG_KEX_DH_GEX_INIT |
| stosb |
| mov esi, dh_e |
| mov esi, con.dh_e |
| call mpint_to_big_endian |
| |
| DEBUGF 1, "Sending GEX init\n" |
| mov ecx, dword[tx_buffer+ssh_header.message_code+1] |
| DEBUGF 2, "Sending GEX init\n" |
| mov ecx, dword[con.tx_buffer.message_code+1] |
| bswap ecx |
| add ecx, 5 |
| stdcall ssh_send_packet, [socketnum], tx_buffer+ssh_header.message_code, ecx, 0 |
| stdcall ssh_send_packet, con, con.tx_buffer.message_code, ecx, 0 |
| cmp eax, -1 |
| je .socket_err |
| |
| 110,58 → 110,54 |
|---|
| ;--------------------------------------------- |
| ; << Parse Diffie-Hellman Group Exchange Reply |
| |
| stdcall ssh_recv_packet, [socketnum], rx_buffer, BUFFERSIZE, 0 |
| stdcall ssh_recv_packet, con, 0 |
| cmp eax, -1 |
| je .socket_err |
| |
| cmp [rx_buffer+ssh_header.message_code], SSH_MSG_KEX_DH_GEX_REPLY |
| cmp [con.rx_buffer.message_code], SSH_MSG_KEX_DH_GEX_REPLY |
| jne .proto_err |
| |
| DEBUGF 1, "Received GEX Reply\n" |
| DEBUGF 2, "Received GEX Reply\n" |
| |
| ;-------------------------------- |
| ; HASH: string K_S, the host key |
| mov esi, rx_buffer+sizeof.ssh_header |
| mov esi, con.rx_buffer+sizeof.ssh_packet_header |
| mov edx, [esi] |
| bswap edx |
| add edx, 4 |
| lea ebx, [esi+edx] |
| push ebx |
| call sha256_update |
| invoke sha256_update, con.temp_ctx, esi, edx |
| |
| ;-------------------------------------------------------------------------- |
| ; HASH: uint32 min, minimal size in bits of an acceptable group |
| ; uint32 n, preferred size in bits of the group the server will send |
| ; uint32 max, maximal size in bits of an acceptable group |
| mov esi, ssh_gex_req+sizeof.ssh_header-ssh_header.message_code |
| mov edx, 12 |
| call sha256_update |
| invoke sha256_update, con.temp_ctx, ssh_gex_req+sizeof.ssh_packet_header-ssh_packet_header.message_code, 12 |
| |
| ;---------------------------- |
| ; HASH: mpint p, safe prime |
| mov esi, dh_p |
| mov esi, con.dh_p |
| mov edi, mpint_tmp |
| call mpint_to_big_endian |
| lea edx, [eax+4] |
| mov esi, mpint_tmp |
| call sha256_update |
| invoke sha256_update, con.temp_ctx, mpint_tmp, edx |
| |
| ;---------------------------------------- |
| ; HASH: mpint g, generator for subgroup |
| mov esi, dh_g |
| mov esi, con.dh_g |
| mov edi, mpint_tmp |
| call mpint_to_big_endian |
| lea edx, [eax+4] |
| mov esi, mpint_tmp |
| call sha256_update |
| invoke sha256_update, con.temp_ctx, mpint_tmp, edx |
| |
| ;--------------------------------------------------- |
| ; HASH: mpint e, exchange value sent by the client |
| mov esi, tx_buffer+sizeof.ssh_header |
| mov esi, con.tx_buffer+sizeof.ssh_packet_header |
| mov edx, [esi] |
| bswap edx |
| add edx, 4 |
| call sha256_update |
| invoke sha256_update, con.temp_ctx, esi, edx |
| |
| ;--------------------------------------------------- |
| ; HASH: mpint f, exchange value sent by the server |
| 169,254 → 165,206 |
|---|
| mov edx, [esi] |
| bswap edx |
| add edx, 4 |
| call sha256_update |
| invoke sha256_update, con.temp_ctx, esi, edx |
| pop esi |
| |
| mov edi, dh_f |
| mov edi, con.dh_f |
| call mpint_to_little_endian |
| |
| DEBUGF 1, "DH f: " |
| stdcall mpint_print, dh_f |
| stdcall mpint_print, con.dh_f |
| |
| mov edi, dh_signature |
| mov edi, con.dh_signature |
| call mpint_to_little_endian |
| |
| DEBUGF 1, "DH signature: " |
| stdcall mpint_print, dh_signature |
| stdcall mpint_print, con.dh_signature |
| |
| ;-------------------------------------- |
| ; Calculate shared secret K = f^x mod p |
| stdcall mpint_modexp, rx_buffer, dh_f, dh_x, dh_p |
| stdcall mpint_length, rx_buffer |
| stdcall mpint_modexp, con.rx_buffer, con.dh_f, con.dh_x, con.dh_p |
| stdcall mpint_length, con.rx_buffer |
| |
| DEBUGF 1, "DH K: " |
| stdcall mpint_print, rx_buffer |
| stdcall mpint_print, con.rx_buffer |
| |
| ; We always need it in big endian order, so store it as such. |
| mov edi, dh_K |
| mov esi, rx_buffer |
| mov edi, con.dh_K |
| mov esi, con.rx_buffer |
| call mpint_to_big_endian |
| mov [dh_K.length], eax |
| mov [con.dh_K_length], eax |
| |
| ;----------------------------------- |
| ; HASH: mpint K, the shared secret |
| mov edx, [dh_K.length] |
| mov edx, [con.dh_K_length] |
| add edx, 4 |
| mov esi, dh_K |
| call sha256_update |
| invoke sha256_update, con.temp_ctx, con.dh_K, edx |
| |
| ;------------------------------- |
| ; Finalize the exchange hash (H) |
| mov edi, dh_H |
| call sha256_final |
| invoke sha256_final, con.temp_ctx |
| mov esi, con.temp_ctx.hash |
| mov edi, con.dh_H |
| mov ecx, SHA256_HASH_SIZE/4 |
| rep movsd |
| |
| DEBUGF 1, "Exchange hash H: " |
| stdcall dump_256bit_hex, dh_H |
| stdcall dump_hex, con.dh_H, 8 |
| |
| ; TODO: skip this block when re-keying |
| mov esi, dh_H |
| mov edi, session_id |
| mov ecx, 32/4 |
| mov esi, con.dh_H |
| mov edi, con.session_id |
| mov ecx, SHA256_HASH_SIZE/4 |
| rep movsd |
| |
| ;--------------- |
| ; Calculate keys |
| |
| ; TODO: re-use partial hash of K and H |
| ; First, calculate partial hash of K and H so we can re-use it for every key. |
| |
| invoke sha256_init, con.k_h_ctx |
| |
| mov edx, [con.dh_K_length] |
| add edx, 4 |
| invoke sha256_update, con.k_h_ctx, con.dh_K, edx |
| invoke sha256_update, con.k_h_ctx, con.dh_H, 32 |
| |
| ;--------------------------------------------------------------- |
| ; Initial IV client to server: HASH(K || H || "A" || session_id) |
| |
| call sha256_init |
| mov edx, [dh_K.length] |
| add edx, 4 |
| mov esi, dh_K |
| call sha256_update |
| mov edx, 32 |
| mov esi, dh_H |
| call sha256_update |
| mov edx, 1 |
| mov esi, str_A |
| call sha256_update |
| mov edx, 32 |
| mov esi, session_id |
| call sha256_update |
| mov edi, tx_iv |
| call sha256_final |
| mov esi, con.k_h_ctx |
| mov edi, con.temp_ctx |
| mov ecx, sizeof.ctx_sha224256/4 |
| rep movsd |
| mov [con.session_id_prefix], 'A' |
| invoke sha256_update, con.temp_ctx, con.session_id_prefix, 32+1 |
| invoke sha256_final, con.temp_ctx.hash |
| mov edi, con.tx_iv |
| mov esi, con.temp_ctx |
| mov ecx, SHA256_HASH_SIZE/4 |
| rep movsd |
| |
| DEBUGF 1, "Remote IV: " |
| stdcall dump_256bit_hex, tx_iv |
| stdcall dump_hex, con.tx_iv, 8 |
| |
| ;--------------------------------------------------------------- |
| ; Initial IV server to client: HASH(K || H || "B" || session_id) |
| |
| call sha256_init |
| mov edx, [dh_K.length] |
| add edx, 4 |
| mov esi, dh_K |
| call sha256_update |
| mov edx, 32 |
| mov esi, dh_H |
| call sha256_update |
| mov edx, 1 |
| mov esi, str_B |
| call sha256_update |
| mov edx, 32 |
| mov esi, session_id |
| call sha256_update |
| mov edi, rx_iv |
| call sha256_final |
| mov esi, con.k_h_ctx |
| mov edi, con.temp_ctx |
| mov ecx, sizeof.ctx_sha224256/4 |
| rep movsd |
| inc [con.session_id_prefix] |
| invoke sha256_update, con.temp_ctx, con.session_id_prefix, 32+1 |
| invoke sha256_final, con.temp_ctx |
| mov edi, con.rx_iv |
| mov esi, con.temp_ctx |
| mov ecx, SHA256_HASH_SIZE/4 |
| rep movsd |
| |
| DEBUGF 1, "Local IV: " |
| stdcall dump_256bit_hex, rx_iv |
| stdcall dump_hex, con.rx_iv, 8 |
| |
| ;------------------------------------------------------------------- |
| ; Encryption key client to server: HASH(K || H || "C" || session_id) |
| |
| call sha256_init |
| mov edx, [dh_K.length] |
| add edx, 4 |
| mov esi, dh_K |
| call sha256_update |
| mov edx, 32 |
| mov esi, dh_H |
| call sha256_update |
| mov edx, 1 |
| mov esi, str_C |
| call sha256_update |
| mov edx, 32 |
| mov esi, session_id |
| call sha256_update |
| mov edi, tx_enc_key |
| call sha256_final |
| mov esi, con.k_h_ctx |
| mov edi, con.temp_ctx |
| mov ecx, sizeof.ctx_sha224256/4 |
| rep movsd |
| inc [con.session_id_prefix] |
| invoke sha256_update, con.temp_ctx, con.session_id_prefix, 32+1 |
| invoke sha256_final, con.temp_ctx |
| mov edi, con.tx_enc_key |
| mov esi, con.temp_ctx |
| mov ecx, SHA256_HASH_SIZE/4 |
| rep movsd |
| |
| DEBUGF 1, "Remote key: " |
| stdcall dump_256bit_hex, tx_enc_key |
| stdcall dump_hex, con.tx_enc_key, 8 |
| |
| ;------------------------------------------------------------------- |
| ; Encryption key server to client: HASH(K || H || "D" || session_id) |
| |
| call sha256_init |
| mov edx, [dh_K.length] |
| add edx, 4 |
| mov esi, dh_K |
| call sha256_update |
| mov edx, 32 |
| mov esi, dh_H |
| call sha256_update |
| mov edx, 1 |
| mov esi, str_D |
| call sha256_update |
| mov edx, 32 |
| mov esi, session_id |
| call sha256_update |
| mov edi, rx_enc_key |
| call sha256_final |
| mov esi, con.k_h_ctx |
| mov edi, con.temp_ctx |
| mov ecx, sizeof.ctx_sha224256/4 |
| rep movsd |
| inc [con.session_id_prefix] |
| invoke sha256_update, con.temp_ctx, con.session_id_prefix, 32+1 |
| invoke sha256_final, con.temp_ctx |
| mov edi, con.rx_enc_key |
| mov esi, con.temp_ctx |
| mov ecx, SHA256_HASH_SIZE/4 |
| rep movsd |
| |
| DEBUGF 1, "Local key: " |
| stdcall dump_256bit_hex, rx_enc_key |
| stdcall dump_hex, con.rx_enc_key, 8 |
| |
| ;------------------------------------------------------------------ |
| ; Integrity key client to server: HASH(K || H || "E" || session_id) |
| |
| call sha256_init |
| mov edx, [dh_K.length] |
| add edx, 4 |
| mov esi, dh_K |
| call sha256_update |
| mov edx, 32 |
| mov esi, dh_H |
| call sha256_update |
| mov edx, 1 |
| mov esi, str_E |
| call sha256_update |
| mov edx, 32 |
| mov esi, session_id |
| call sha256_update |
| mov edi, tx_int_key |
| call sha256_final |
| mov esi, con.k_h_ctx |
| mov edi, con.temp_ctx |
| mov ecx, sizeof.ctx_sha224256/4 |
| rep movsd |
| inc [con.session_id_prefix] |
| invoke sha256_update, con.temp_ctx, con.session_id_prefix, 32+1 |
| invoke sha256_final, con.temp_ctx |
| mov edi, con.tx_int_key |
| mov esi, con.temp_ctx |
| mov ecx, SHA256_HASH_SIZE/4 |
| rep movsd |
| |
| DEBUGF 1, "Remote Integrity key: " |
| stdcall dump_256bit_hex, tx_int_key |
| stdcall dump_hex, con.tx_int_key, 8 |
| |
| ;------------------------------------------------------------------ |
| ; Integrity key server to client: HASH(K || H || "F" || session_id) |
| |
| call sha256_init |
| mov edx, [dh_K.length] |
| add edx, 4 |
| mov esi, dh_K |
| call sha256_update |
| mov edx, 32 |
| mov esi, dh_H |
| call sha256_update |
| mov edx, 1 |
| mov esi, str_F |
| call sha256_update |
| mov edx, 32 |
| mov esi, session_id |
| call sha256_update |
| mov edi, rx_int_key |
| call sha256_final |
| mov esi, con.k_h_ctx |
| mov edi, con.temp_ctx |
| mov ecx, sizeof.ctx_sha224256/4 |
| rep movsd |
| inc [con.session_id_prefix] |
| invoke sha256_update, con.temp_ctx, con.session_id_prefix, 32+1 |
| invoke sha256_final, con.temp_ctx |
| mov edi, con.rx_int_key |
| mov esi, con.temp_ctx |
| mov ecx, SHA256_HASH_SIZE/4 |
| rep movsd |
| |
| DEBUGF 1, "Local Integrity key: " |
| stdcall dump_256bit_hex, rx_int_key |
| stdcall dump_hex, con.rx_int_key, 8 |
| |
| ;------------------------------------- |
| ; << Parse Diffie-Hellman New Keys MSG |
| |
| stdcall ssh_recv_packet, [socketnum], rx_buffer, BUFFERSIZE, 0 |
| stdcall ssh_recv_packet, con, 0 |
| cmp eax, -1 |
| je .socket_err |
| |
| cmp [rx_buffer+ssh_header.message_code], SSH_MSG_NEWKEYS |
| cmp [con.rx_buffer.message_code], SSH_MSG_NEWKEYS |
| jne .proto_err |
| |
| DEBUGF 1, "Received New Keys\n" |
| DEBUGF 2, "Received New Keys\n" |
| |
| ;------------------------------- |
| ; >> Reply with New Keys message |
| |
| stdcall ssh_send_packet, [socketnum], ssh_new_keys, ssh_new_keys.length, 0 |
| stdcall ssh_send_packet, con, ssh_new_keys, ssh_new_keys.length, 0 |
| |
| xor eax, eax |
| ret |
| |
| .socket_err: |
| DEBUGF 2, "Socket error during key exchange!\n" |
| DEBUGF 3, "Socket error during key exchange!\n" |
| mov eax, 1 |
| ret |
| |
| .proto_err: |
| DEBUGF 2, "Protocol error during key exchange!\n" |
| DEBUGF 3, "Protocol error during key exchange!\n" |
| mov eax, 2 |
| ret |
| |
| endp |
| |
| proc dump_256bit_hex _ptr |
| pushad |
| |
| mov esi, [_ptr] |
| mov ecx, 8 |
| .next_dword: |
| lodsd |
| bswap eax |
| DEBUGF 1,'%x',eax |
| loop .next_dword |
| DEBUGF 1,'\n' |
| |
| popad |
| ret |
| endp |
| |
| iglobal |
| |
| str_A db 'A' |
| str_B db 'B' |
| str_C db 'C' |
| str_D db 'D' |
| str_E db 'E' |
| str_F db 'F' |
| |
| endg |