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hidnplayr |
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; ssh_transport.inc - SSH transport layer |
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; |
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; Copyright (C) 2016 Jeffrey Amelynck |
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; |
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; This program is free software: you can redistribute it and/or modify |
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; it under the terms of the GNU General Public License as published by |
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; the Free Software Foundation, either version 3 of the License, or |
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; (at your option) any later version. |
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; |
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; This program is distributed in the hope that it will be useful, |
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; but WITHOUT ANY WARRANTY; without even the implied warranty of |
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; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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; GNU General Public License for more details. |
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; |
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; You should have received a copy of the GNU General Public License |
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; along with this program. If not, see . |
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struct ssh_header |
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length dd ? |
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padding db ? |
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message_code db ? |
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ends |
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proc dummy_encrypt _key, _in, _out |
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ret |
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endp |
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proc ssh_recv_packet sock, buf, size, flags |
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locals |
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bufferptr dd ? |
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remaining dd ? |
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padding dd ? |
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endl |
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DEBUGF 1, "ssh_recv_packet\n" |
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; Receive first block (Read length, padding length, message code) |
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mcall recv, [sock], [buf], [rx_blocksize], [flags] |
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DEBUGF 1, "chunk = %u\n", eax |
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cmp eax, [rx_blocksize] |
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jne .fail ;;;; |
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; stdcall [decrypt_proc], [rx_context], [buf], [buf] |
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mov ebx, [buf] |
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movzx eax, [ebx+ssh_header.padding] |
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mov [padding], eax |
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mov eax, [ebx+ssh_header.length] |
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bswap eax ; length to little endian |
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mov [ebx+ssh_header.length], eax |
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DEBUGF 1, "ssh_recv_packet length = %u\n", eax |
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cmp eax, [size] |
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ja .fail ;;;; |
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sub eax, [rx_blocksize] |
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add eax, 4 |
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mov [remaining], eax |
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add ebx, [rx_blocksize] |
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mov [bufferptr], ebx |
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.receive_loop: |
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mcall recv, [sock], [bufferptr], [remaining], 0 |
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DEBUGF 1, "chunk = %u\n", eax |
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cmp eax, 0 |
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jbe .fail |
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add [bufferptr], eax |
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sub [remaining], eax |
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ja .receive_loop |
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; .decrypt_loop: |
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; stdcall [decrypt_proc], [rx_context], [buf], [buf] |
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; ja .decrypt_loop |
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; .hmac_loop: |
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; TODO |
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; ja .hmac_loop |
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; Return usefull data length in eax |
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mov eax, [buf] |
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movzx ebx, [eax+ssh_header.padding] |
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mov eax, [eax+ssh_header.length] |
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sub eax, ebx |
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DEBUGF 1, "ssh_recv_packet complete, usefull data length=%u\n", eax |
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ret |
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.fail: |
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DEBUGF 1, "ssh_recv_packet failed!\n" |
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mov eax, -1 |
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ret |
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endp |
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proc ssh_send_packet sock, buf, payloadsize, flags |
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locals |
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size dd ? |
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endl |
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DEBUGF 1, "ssh_send_packet: size=%u\n", [payloadsize] |
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mov eax, [payloadsize] |
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inc eax ; padding length byte |
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lea edx, [eax+4] ; total packet size (without padding) |
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mov [size], edx |
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mov ebx, [tx_blocksize] |
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dec ebx |
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and edx, ebx |
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neg edx |
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add edx, [tx_blocksize] |
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cmp edx, 4 ; minimum padding size |
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jae @f |
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add edx, [tx_blocksize] |
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@@: |
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DEBUGF 1, "Padding %u bytes\n", edx |
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add [size], edx |
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add eax, edx |
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DEBUGF 1, "Total size: %u\n", eax |
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bswap eax |
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mov edi, tx_buffer |
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stosd |
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mov al, dl |
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stosb |
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mov esi, [buf] |
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; cmp esi, edi |
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; je @f |
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mov ecx, [payloadsize] |
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rep movsb |
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; @@: |
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mov ebx, edx |
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mov esi, edx |
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and ebx, 3 |
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jz @f |
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call MBRandom |
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mov dword[edi], eax |
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add edi, ebx |
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@@: |
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shr esi, 2 |
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@@: |
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call MBRandom |
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stosd |
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dec esi |
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jnz @r |
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mcall send, [sock], tx_buffer, [size], [flags] |
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ret |
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endp |