Re: 0.5.5 Hang on sftp_new calling channel_open()

[Andreas Schneider <asn@xxxxxxxxxxxxxx>]

On Tuesday 05 November 2013 11:31:00 Kevin Lambert wrote:
> I have a Digi WR21 modem that if I attempt to make an sftp_new() call while
> the modem is still booting I get a hang in channel_open() because the
> channel->state never switches from SSH_CHANNEL_STATE_NOT_OPEN and there
> isn't a check on the session timeout in:
> 
>   /* Todo: fix this into a correct loop */
> 
>   /* wait until channel is opened by server */
> 
>   while(channel->state == SSH_CHANNEL_STATE_NOT_OPEN){
> 
>     ssh_handle_packets(session,-1);
> 
>   }

Can you please try libssh 0.6.0rc2?
 
> 
> 
> So the the open call is stuck in that while loop without a way to break out.
> Is there any reason why a check cant be added against the session->timeout
> parameter like so:
> 
> 
> 
> static int channel_open(ssh_channel channel, const char *type_c, int window,
> 
>     int maxpacket, ssh_buffer payload) {
> 
>   ssh_session session = channel->session;
> 
>   ssh_string type = NULL;
> 
>   int err=SSH_ERROR;
> 
>   int useTimeout = (session->timeout + (1000 * session->timeout_usec)) > 0;
> 
>   time_t timeout = time(NULL) + session->timeout + (1000 *
> session->timeout_usec);
> 
> 
> 
>   enter_function();
> 
>   channel->local_channel = ssh_channel_new_id(session);
> 
>   channel->local_maxpacket = maxpacket;
> 
>   channel->local_window = window;
> 
> 
> 
>   ssh_log(session, SSH_LOG_PROTOCOL,
> 
>       "Creating a channel %d with %d window and %d max packet",
> 
>       channel->local_channel, window, maxpacket);
> 
> 
> 
>   type = ssh_string_from_char(type_c);
> 
>   if (type == NULL) {
> 
>     ssh_set_error_oom(session);
> 
>     leave_function();
> 
>     return err;
> 
>   }
> 
> 
> 
>   if (buffer_add_u8(session->out_buffer, SSH2_MSG_CHANNEL_OPEN) < 0 ||
> 
>       buffer_add_ssh_string(session->out_buffer,type) < 0 ||
> 
>       buffer_add_u32(session->out_buffer, htonl(channel->local_channel)) < 0
> 
> 
>       buffer_add_u32(session->out_buffer, htonl(channel->local_window)) < 0
> 
> 
>       buffer_add_u32(session->out_buffer, htonl(channel->local_maxpacket)) <
> 0) {
> 
>     ssh_set_error_oom(session);
> 
>     ssh_string_free(type);
> 
>     leave_function();
> 
>     return err;
> 
>   }
> 
> 
> 
>   ssh_string_free(type);
> 
> 
> 
>   if (payload != NULL) {
> 
>     if (buffer_add_buffer(session->out_buffer, payload) < 0) {
> 
>       ssh_set_error_oom(session);
> 
>       leave_function();
> 
>       return err;
> 
>     }
> 
>   }
> 
> 
> 
>   if (packet_send(session) == SSH_ERROR) {
> 
>     leave_function();
> 
>     return err;
> 
>   }
> 
> 
> 
>   ssh_log(session, SSH_LOG_PACKET,
> 
>       "Sent a SSH_MSG_CHANNEL_OPEN type %s for channel %d",
> 
>       type_c, channel->local_channel);
> 
> 
> 
>   /* Todo: fix this into a correct loop */
> 
>   /* wait until channel is opened by server */
> 
>   while(channel->state == SSH_CHANNEL_STATE_NOT_OPEN && (!useTimeout ||
> (useTimeout && (time(NULL) < timeout))) ){
> 
>     ssh_handle_packets(session,-1);
> 
>   }
> 
>   if(channel->state == SSH_CHANNEL_STATE_OPEN)
> 
>     err=SSH_OK;
> 
>   leave_function();
> 
>   return err;
> 
> }

-- 
Andreas Schneider                   GPG-ID: CC014E3D
www.cryptomilk.org                asn@xxxxxxxxxxxxxx