225 lines
7.9 KiB
PHP
Executable File
225 lines
7.9 KiB
PHP
Executable File
; sshlib_transport.inc - SSH transport layer
|
|
;
|
|
; Copyright (C) 2016-2024 Jeffrey Amelynck
|
|
;
|
|
; 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 3 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, see <http://www.gnu.org/licenses/>.
|
|
|
|
align 16
|
|
proc sshlib_recv_packet_hmac_etm con_ptr, flags
|
|
|
|
locals
|
|
data_length dd ? ; Total length of packet without MAC
|
|
endl
|
|
|
|
DEBUGF 3, "> "
|
|
; Receive first block (Read length)
|
|
mov ebx, [con_ptr]
|
|
mov ecx, [ebx+sshlib_connection.socketnum]
|
|
mov esi, 4
|
|
lea edx, [ebx+sshlib_connection.rx_buffer]
|
|
mov edi, [flags]
|
|
mcall recv
|
|
cmp eax, 0
|
|
jle .sock_fail
|
|
sub [ssh_chan.rcv_wnd], eax ;;; FIXME
|
|
DEBUGF 1, "chunk = %u ", eax
|
|
mov ebx, [con_ptr]
|
|
cmp eax, 4
|
|
jne .proto_fail ; TODO: handle receives of 1, 2, and 3 bytes correctly
|
|
|
|
mov eax, [ebx+sshlib_connection.rx_buffer.packet_length]
|
|
bswap eax
|
|
mov [data_length], eax
|
|
DEBUGF 2, "decrypted packet length=%u\n", [data_length]
|
|
|
|
add eax, [ebx + sshlib_connection.rx_mac_length]
|
|
cmp eax, BUFFERSIZE-4
|
|
ja .proto_fail
|
|
|
|
; Receive remaining data
|
|
lea edx, [ebx+sshlib_connection.rx_buffer+4]
|
|
mov ecx, [ebx+sshlib_connection.socketnum]
|
|
mov edi, [flags]
|
|
mov esi, eax
|
|
.recv_loop:
|
|
DEBUGF 3, "want %u bytes.. ", esi
|
|
mcall recv
|
|
cmp eax, 0
|
|
jle .sock_fail
|
|
sub [ssh_chan.rcv_wnd], eax ;;; FIXME
|
|
DEBUGF 3, "got %u bytes\n", eax
|
|
add edx, eax
|
|
sub esi, eax
|
|
jnz .recv_loop
|
|
|
|
; Authenticate message
|
|
mov ebx, [con_ptr]
|
|
lea esi, [ebx + sshlib_connection.rx_mac_seqnr]
|
|
mov ecx, [data_length]
|
|
add ecx, 8 ; packet_length field itself + sequence number
|
|
lea eax, [ebx + sshlib_connection.rx_mac_ctx]
|
|
lea edx, [ebx + sshlib_connection.rx_int_key]
|
|
stdcall [ebx + sshlib_connection.rx_mac_proc], eax, esi, ecx, edx, SHA2_256_LEN
|
|
|
|
lea esi, [ebx + sshlib_connection.rx_mac_ctx]
|
|
lea edi, [ebx + sshlib_connection.rx_buffer+4]
|
|
add edi, [data_length]
|
|
mov ecx, [ebx + sshlib_connection.rx_mac_length]
|
|
shr ecx, 2
|
|
repe cmpsd ; TODO: constant time
|
|
jne .mac_fail
|
|
|
|
; Decrypt the payload
|
|
lea eax, [ebx+sshlib_connection.rx_crypt_ctx]
|
|
lea edi, [ebx+sshlib_connection.rx_buffer+4]
|
|
stdcall [ebx + sshlib_connection.rx_crypt_proc], eax, edi, [data_length], edi
|
|
|
|
; Update sequence counter
|
|
add byte[ebx+sshlib_connection.rx_mac_seqnr+3], 1
|
|
adc byte[ebx+sshlib_connection.rx_mac_seqnr+2], 0
|
|
adc byte[ebx+sshlib_connection.rx_mac_seqnr+1], 0
|
|
adc byte[ebx+sshlib_connection.rx_mac_seqnr+0], 0
|
|
|
|
; Return useful data length to the caller via eax register
|
|
mov eax, [data_length]
|
|
mov [ebx+sshlib_connection.rx_buffer.packet_length], eax
|
|
movzx ebx, [ebx+sshlib_connection.rx_buffer.padding_length]
|
|
sub eax, ebx
|
|
DEBUGF 1, "useful data length=%u\n", eax
|
|
ret
|
|
|
|
.sock_fail:
|
|
DEBUGF 3, "ssh_recv_packet failed!\n"
|
|
mov eax, SSHLIB_ERR_SOCKET
|
|
ret
|
|
|
|
.mac_fail:
|
|
DEBUGF 3, "ssh_recv_packet message authentication failed!\n"
|
|
mov eax, SSHLIB_ERR_MAC_VERIFY_FAIL
|
|
xor ebx, ebx
|
|
ret
|
|
|
|
.proto_fail:
|
|
DEBUGF 3, "ssh_recv_packet protocol failure!\n"
|
|
mov eax, SSHLIB_ERR_PROTOCOL
|
|
xor ebx, ebx
|
|
ret
|
|
|
|
endp
|
|
|
|
|
|
align 16
|
|
proc sshlib_send_packet_hmac_etm con_ptr, buf, payload_size, flags
|
|
|
|
locals
|
|
padded_size dd ? ; payload with padding (without length field or MAC)
|
|
endl
|
|
DEBUGF 2, "< "
|
|
|
|
; Check how many bytes we should pad
|
|
mov eax, [payload_size]
|
|
inc eax ; padding length byte
|
|
|
|
mov ecx, [con_ptr]
|
|
mov edx, eax
|
|
mov ebx, [ecx + sshlib_connection.tx_pad_size]
|
|
dec ebx
|
|
and edx, ebx
|
|
neg edx
|
|
add edx, [ecx + sshlib_connection.tx_pad_size]
|
|
add edx, [ecx + sshlib_connection.tx_pad_size]
|
|
DEBUGF 2, "padding %u bytes ", edx
|
|
add eax, edx
|
|
mov [padded_size], eax ; total packet size with padding, without MAC
|
|
|
|
; Start building the packet
|
|
; First comes the packet length, in network byte order ofcourse.
|
|
DEBUGF 2, "total size: %u ", eax
|
|
bswap eax
|
|
lea edi, [ecx + sshlib_connection.tx_buffer]
|
|
stosd
|
|
; Then the padding length
|
|
mov al, dl
|
|
stosb
|
|
;;; And the actual payload bytes
|
|
mov esi, [buf]
|
|
mov ecx, [payload_size]
|
|
rep movsb
|
|
|
|
; Append the packet with #edx padding bytes.
|
|
; Since we must pad at least 8 bytes, we can always use DWORD writes.
|
|
; First do an (unaligned) write exactly following the data
|
|
dec edx
|
|
mov esi, edx
|
|
shr esi, 2 ; number dwords
|
|
mov ebx, edx
|
|
and ebx, 3
|
|
inc ebx ; number bytes in first write (1-4)
|
|
call MBRandom
|
|
mov dword[edi], eax
|
|
add edi, ebx
|
|
; Then, do as many aligned writes as nescessary
|
|
@@:
|
|
call MBRandom
|
|
stosd
|
|
dec esi
|
|
jnz @r
|
|
|
|
; Encrypt the payload
|
|
mov ebx, [con_ptr]
|
|
lea esi, [ebx + sshlib_connection.tx_crypt_ctx]
|
|
lea edi, [ebx + sshlib_connection.tx_buffer+4]
|
|
stdcall [ebx + sshlib_connection.tx_crypt_proc], esi, edi, [padded_size], edi
|
|
|
|
; Append the packet with Message Authentication Code
|
|
; mov ebx, [con_ptr]
|
|
DEBUGF 1, "MAC sequence number: 0x%x\n", [ebx + sshlib_connection.tx_mac_seqnr]
|
|
lea esi, [ebx + sshlib_connection.tx_mac_seqnr]
|
|
mov ecx, [padded_size]
|
|
add ecx, 8 ; Sequence number length + packet length field
|
|
lea eax, [ebx + sshlib_connection.tx_mac_ctx]
|
|
lea edx, [ebx + sshlib_connection.tx_int_key]
|
|
stdcall [ebx + sshlib_connection.tx_mac_proc], eax, esi, ecx, edx, SHA2_256_LEN
|
|
|
|
mov ebx, [con_ptr]
|
|
lea esi, [ebx + sshlib_connection.tx_mac_ctx]
|
|
lea edi, [ebx + sshlib_connection.tx_buffer+4]
|
|
add edi, [padded_size]
|
|
mov ecx, [ebx + sshlib_connection.tx_mac_length]
|
|
shr ecx, 2
|
|
rep movsd
|
|
|
|
; Update sequence counter
|
|
add byte[ebx+sshlib_connection.tx_mac_seqnr+3], 1
|
|
adc byte[ebx+sshlib_connection.tx_mac_seqnr+2], 0
|
|
adc byte[ebx+sshlib_connection.tx_mac_seqnr+1], 0
|
|
adc byte[ebx+sshlib_connection.tx_mac_seqnr+0], 0
|
|
|
|
; Send the packet
|
|
; mov ebx, [con_ptr]
|
|
mov ecx, [ebx+sshlib_connection.socketnum]
|
|
lea edx, [ebx+sshlib_connection.tx_buffer]
|
|
mov esi, [padded_size]
|
|
add esi, 4
|
|
add esi, [ebx+sshlib_connection.tx_mac_length]
|
|
mov edi, [flags]
|
|
mcall send
|
|
|
|
DEBUGF 2, "\n"
|
|
|
|
ret
|
|
|
|
endp
|
|
|