Re: 0.5.5 Hang on sftp_new calling channel_open()

[Ashish Mangla <Ashish.Mangla@xxxxxxxxxxxxxx>]

Sent from Samsung Note II


-------- Original message --------
From: Andreas Schneider <asn@xxxxxxxxxxxxxx>
Date: 22/11/2013 17:04 (GMT+05:30)
To: libssh@xxxxxxxxxx
Cc: Kevin Lambert <klambert@xxxxxxxxx>
Subject: Re: 0.5.5 Hang on sftp_new calling channel_open()


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<http://www.cryptomilk.org>                asn@xxxxxxxxxxxxxx