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Pad with 0 bytes before encryption is set, as not to leak any entropy of RNG.

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Little improved RNG seeding.
Fixed bug in MAC counter for SSH transport.

git-svn-id: svn://kolibrios.org@9071 a494cfbc-eb01-0410-851d-a64ba20cac60
This commit is contained in:
hidnplayr
2021-07-21 10:53:13 +00:00
parent 66f0a0e45d
commit 4f24fcab0f
4 changed files with 138 additions and 45 deletions
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28
programs/network/ssh/ssh.asm
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@@ -51,6 +51,7 @@ include 'ssh_transport.inc'
include 'dh_gex.inc'
include 'mpint.inc'
include 'seed.inc'
include 'random.inc'
include 'aes256.inc'
@@ -118,8 +119,11 @@ struct ssh_connection
rx_crypt_blocksize dd ?
tx_crypt_blocksize dd ?
rx_padsize dd ? ; = Max(8, rx_crypt_blocksize)
tx_padsize dd ? ; = Max(8, tx_crypt_blocksize)
; Padding
; rx_padsize dd ? ; = Max(8, rx_crypt_blocksize)
tx_pad_size dd ? ; = Max(8, tx_crypt_blocksize)
tx_pad_proc dd ?
; Message authentication
@@ -189,6 +193,7 @@ start:
jnz exit
DEBUGF 2, "SSH: Init PRNG\n"
call create_seed
call init_random
DEBUGF 2, "SSH: Init Console\n"
@@ -335,8 +340,9 @@ resolve:
mov [con.tx_mac_proc], 0
mov [con.rx_mac_length], 0
mov [con.tx_mac_length], 0
mov [con.rx_padsize], 8 ; minimum padsize
mov [con.tx_padsize], 8
; mov [con.rx_padsize], 8 ; minimum padsize
mov [con.tx_pad_size], 8
mov [con.tx_pad_proc], padding_zero
DEBUGF 2, "Sending KEX init\n"
mov edi, ssh_kex.cookie
@@ -436,7 +442,7 @@ resolve:
test eax, eax
jnz exit
; Set keys
; Set keys and initialize transport subroutines
DEBUGF 2, "SSH: Setting encryption keys\n"
@@ -446,7 +452,7 @@ resolve:
stdcall aes256_set_encrypt_key, eax, con.rx_enc_key
mov [con.rx_crypt_proc], aes256_ctr_crypt
mov [con.rx_crypt_blocksize], AES256_BLOCKSIZE
mov [con.rx_padsize], AES256_BLOCKSIZE
; mov [con.rx_pad_size], AES256_BLOCKSIZE
stdcall aes256_ctr_init, con.tx_iv
mov [con.tx_crypt_ctx_ptr], eax
@@ -454,7 +460,9 @@ resolve:
stdcall aes256_set_encrypt_key, eax, con.tx_enc_key
mov [con.tx_crypt_proc], aes256_ctr_crypt
mov [con.tx_crypt_blocksize], AES256_BLOCKSIZE
mov [con.tx_padsize], AES256_BLOCKSIZE
mov [con.tx_pad_size], AES256_BLOCKSIZE
mov [con.tx_pad_proc], MBRandom
stdcall hmac_sha256_setkey, con.rx_mac_ctx, con.rx_int_key, SHA256_HASH_SIZE
mov [con.rx_mac_proc], hmac_sha256
@@ -464,6 +472,10 @@ resolve:
mov [con.tx_mac_proc], hmac_sha256
mov [con.tx_mac_length], SHA256_HASH_SIZE
; Re-seed RNG for padding bytes
call create_seed
call init_random
; TODO: erase all keys from memory and free the memory
; >> Request service (user-auth)
@@ -778,7 +790,7 @@ str14 db 10, 27, '[?25h', 27, '[0m', 0
ssh_ident_ha:
dd_n (ssh_ident.length-2)
ssh_ident:
db "SSH-2.0-KolibriOS_SSH_0.03",13,10
db "SSH-2.0-KolibriOS_SSH_0.04",13,10
.length = $ - ssh_ident
ssh_kex: