Implemented local storage and checking of remote host keys. (only ssh-rsa for now)

Known public keys will be stored in /sys/settings/known_hosts.ini

git-svn-id: svn://kolibrios.org@9112 a494cfbc-eb01-0410-851d-a64ba20cac60

programs/network/ssh/ssh.asm

@@ -142,7 +142,7 @@ start:
 
         DEBUGF  2, "SSH: Init Console\n"
         invoke  con_start, 1
-        invoke  con_init, 80, 25, 800, 250, title
+        invoke  con_init, 80, 25, 80, 250, title
 
         cmp     byte[params], 0
         jne     main.connect
@@ -388,8 +388,9 @@ proc sshlib_callback_hostkey_problem, con_ptr, problem_type, hostkey_sz
         invoke  con_write_asciiz, str23
 ;        jmp     .ask
   .ask:
-  ;;; TODO: print hostkey
+        invoke  con_write_asciiz, str24a
-        invoke  con_write_asciiz, str24
+        invoke  con_write_asciiz, [hostkey_sz]
+        invoke  con_write_asciiz, str24b
   .getansw:
         invoke  con_getch2
         or      al, 0x20        ; convert to lowercase
@@ -471,7 +472,8 @@ str22   db "The host key for the server was not found in the cache.", 10
 str23   db "The host key provided by the host does not match the cached one.", 10
         db "This may indicate that the remote server has been compromised!", 10, 0
 
-str24   db 10, "If you trust this host, press A to accept and store the (new) key.", 10
+str24a  db 10, "The remote host key is: ", 10, 0
+str24b  db 10, 10, "If you trust this host, press A to accept and store the (new) key.", 10
         db "Press C to connect to the host but don't store the (new) key.", 10
         db "Press X to abort.", 10, 0
 
@@ -479,7 +481,7 @@ str24   db 10, "If you trust this host, press A to accept and store the (new) ke
 ssh_ident_ha:
         dd_n (ssh_msg_ident.length-2)
 ssh_msg_ident:
-        db "SSH-2.0-KolibriOS_SSH_0.05",13,10
+        db "SSH-2.0-KolibriOS_SSH_0.06",13,10
   .length = $ - ssh_msg_ident
 
 
@@ -592,7 +594,8 @@ align 4
 
 library network, 'network.obj', \
         console, 'console.obj', \
-        libcrash, 'libcrash.obj'
+        libcrash, 'libcrash.obj', \
+        libini, 'libini.obj'
 
 import  network, \
         getaddrinfo, 'getaddrinfo', \
@@ -622,6 +625,10 @@ import  libcrash, \
         md5_update, 'md5_update', \
         md5_final, 'md5_final'
 
+import  libini, \
+        ini_get_str, 'ini_get_str', \
+        ini_set_str, 'ini_set_str'
+
 IncludeIGlobals
 
 i_end:

programs/network/ssh/sshlib_host.inc

@@ -18,13 +18,21 @@
 ; https://datatracker.ietf.org/doc/html/rfc4253#section-6.6
 ; https://datatracker.ietf.org/doc/html/rfc3447
 
+; https://datatracker.ietf.org/doc/html/rfc4716
+
 proc sshlib_host_verify  con_ptr, str_host_key, str_signature, message, message_len
 
 locals
-        known_key_sz rb MAX_PUBLIC_KEY_SIZE
+        current_hkb64           rb MAX_PUBLIC_KEY_SIZE*4        ; Current Host key in Base64
+        cached_hkb64            rb MAX_PUBLIC_KEY_SIZE*4        ; Cached Host key in Base64
+        key_name_sz             dd ?
+        hostname_sz             dd ?
+        current_hk64_end        dd ?
 endl
 
         mov     eax, [con_ptr]
+        lea     ebx, [eax + sshlib_connection.hostname_sz]
+        mov     [hostname_sz], ebx
         cmp     [eax+sshlib_connection.algo_hostkey], SSHLIB_HOSTKEY_RSA
         je      .rsa
         ; ..add more here
@@ -35,40 +43,65 @@ endl
         stdcall sshlib_host_verify_rsa, [str_host_key], [str_signature], [message], [message_len]
         test    eax, eax
         jnz     .err
+        mov     [key_name_sz], ssh_rsa_sz
 
   .lookup:
-;        lea     eax, [known_key_sz]
+; Convert the current host key to base64
-;        mov     ebx, [con_ptr]
+        mov     esi, [str_host_key]
-;        lea     ebx, [ebx + sshlib_connection.hostname_sz]
+        mov     ecx, [esi]
-;        invoke  ini_get_str, known_hosts_file, ebx, ssh_rsa_sz, eax, MAX_PUBLIC_KEY_SIZE, null_sz
+        bswap   ecx
-;        test    eax, eax
+        add     esi, 4
-;        jnz     .unknown
+        lea     edi, [current_hkb64]
+        call    base64_encode
+        mov     [current_hk64_end], edi
 
-; TODO: verify cached host key
+; Try to read the cached key for this host and key type
-;        jne     .mismatch
+        lea     edi, [cached_hkb64]
-
+        invoke  ini_get_str, known_hostsfile, [hostname_sz], [key_name_sz], edi, MAX_PUBLIC_KEY_SIZE*4, 0
-        jmp     .unknown        ; FIXME
+        test    eax, eax
+        jnz     .unknown
+; If the cached key is empty, return SSHLIB_HOSTKEY_PROBLEM_UNKNOWN
+        lea     esi, [cached_hkb64]
+        cmp     byte[esi], 0
+        je      .unknown
+; Else, compare it to the current one
+        lea     edi, [current_hkb64]
+        mov     ecx, MAX_PUBLIC_KEY_SIZE*4
+  .cmploop:
+        lodsb
+        scasb
+        jne     .mismatch
+        test    al, al
+        jz      .match
+        dec     ecx
+        jnz     .cmploop
+        jmp     .mismatch
 
+  .match:
         xor     eax, eax
         ret
 
   .mismatch:
-        lea     eax, [known_key_sz]
+int3
+        lea     eax, [current_hkb64]
         stdcall sshlib_callback_hostkey_problem, [con_ptr], SSHLIB_HOSTKEY_PROBLEM_MISMATCH, eax
         cmp     eax, SSHLIB_HOSTKEY_ACCEPT
         je      .store
         ret
 
   .unknown:
-        lea     eax, [known_key_sz]
+        lea     eax, [current_hkb64]
         stdcall sshlib_callback_hostkey_problem, [con_ptr], SSHLIB_HOSTKEY_PROBLEM_UNKNOWN, eax
         cmp     eax, SSHLIB_HOSTKEY_ACCEPT
         je      .store
         ret
 
   .store:
-; TODO: write to know_hosts file and fall-through
+        lea     esi, [current_hkb64]
-
+        mov     ecx, [current_hk64_end]
+        sub     ecx, esi
+        invoke  ini_set_str, known_hostsfile, [hostname_sz], [key_name_sz], esi, ecx
+        xor     eax, eax
         ret
 
   .err:
@@ -234,10 +267,64 @@ endl
 endp
 
 
+base64_encode:
+
+        xor     ebx, ebx
+  .loop:
+        lodsb
+        call    .byte
+        dec     ecx
+        jnz     .loop
+
+  .final:
+        mov     al, 0
+        test    ebx, ebx
+        jz      .f000
+        call    .byte
+        test    ebx, ebx
+        jz      .f001
+        call    .byte
+        mov     byte[edi-2], '='
+
+  .f001:
+        mov     byte[edi-1], '='
+
+  .f000:
+        mov     byte[edi], 0
+        ret
+
+  .byte:
+        inc     ebx
+        shl     edx, 8
+        mov     dl, al
+        cmp     ebx, 3
+        je      .b001
+        ret
+
+  .b001:
+        shl     edx, 8
+        inc     ebx
+
+  .b002:
+        rol     edx, 6
+        xor     eax, eax
+        xchg    al, dl
+        mov     al, [base64_table+eax]
+        stosb
+        dec     ebx
+        jnz     .b002
+        ret
+
+
+
+
 iglobal
 
+        known_hostsfile db '/sys/settings/known_hosts.ini', 0
+        base64_table    db 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'
         rsa_sha1_t      db 0x30, 0x21, 0x30, 0x09, 0x06, 0x05, 0x2B, 0x0E, 0x03, 0x02, 0x1A, 0x05, 0x00, 0x04, 0x14
         .len = $ - rsa_sha1_t
+        ssh_rsa_sz      db 'ssh-rsa', 0
 
 endg