Extend nasl_ssh functions to support non-interactive shell (pty disab…

…led).

Currently there are two options:

- an interactive shell with pty enabled, which responses are quite verbose (cmds, prompt, etc).
- one shot cmd exec which close the channel, with the response of the command only.

The new option allows to run multiple commands and only get the answer of this command, whitout the extra data like prompts and commands sent to the target.

nasl/nasl_ssh.c

@@ -1653,19 +1653,25 @@ request_ssh_shell_alarm (int signal)
  * @return 0 if success, -1 if error.
  */
 static int
-request_ssh_shell (ssh_channel channel)
+request_ssh_shell (ssh_channel channel, int pty)
 {
   assert (channel);
 
   /* Work-around for LibSSH calling poll() with an infinite timeout. */
   signal (SIGALRM, request_ssh_shell_alarm);
   alarm (30);
-  if (ssh_channel_request_pty (channel))
-    return -1;
-  if (ssh_channel_change_pty_size (channel, 80, 24))
-    return -1;
+
+  if (pty == 1)
+    {
+      if (ssh_channel_request_pty (channel))
+        return -1;
+
+      if (ssh_channel_change_pty_size (channel, 80, 24))
+        return -1;
+    }
   if (ssh_channel_request_shell (channel))
     return -1;
+
   alarm (0);
   signal (SIGALRM, _exit);
 
@@ -1689,12 +1695,14 @@ request_ssh_shell (ssh_channel channel)
 tree_cell *
 nasl_ssh_shell_open (lex_ctxt *lexic)
 {
-  int tbl_slot, session_id;
+  int tbl_slot, session_id, pty;
   ssh_channel channel;
   ssh_session session;
   tree_cell *retc;
 
   session_id = get_int_var_by_num (lexic, 0, -1);
+  pty = get_int_var_by_name (lexic, "pty", 1);
+
   if (!verify_session_id (session_id, "ssh_shell_open", &tbl_slot, lexic))
     return NULL;
   session = session_table[tbl_slot].session;
@@ -1711,7 +1719,7 @@ nasl_ssh_shell_open (lex_ctxt *lexic)
       return NULL;
     }
 
-  if (request_ssh_shell (channel))
+  if (request_ssh_shell (channel, pty))
     {
       g_message ("Function %s (calling internal function %s) called from %s: "
                  "request_ssh_shell: %s",