Retrieve scp errors #180

Yannik · 2023-05-15T21:09:33Z

I'm trying to use this lib with paramiko to push a config file to a fortigate. The fortigate has some validation logic to check if the config is valid or not.

Using openssh scp, that looks like this:

$ scp -O config admin@fortigate:fgt-restore-config
admin@fortigate's password: 
config                                                                                        100%  293KB   1.4MB/s   00:00    
500-Invalid config file

...and with -vvv (shortened to the relevant parts):

Sending file modes: C0644 300109 config
config                                                                                          0%    0     0.0KB/s   --:-- ETA
scp: debug2: fd 6 setting O_NONBLOCK
scp: debug1: fd 6 clearing O_NONBLOCK
debug2: channel 0: rcvd adjust 98321
debug2: channel 0: rcvd adjust 131072
config                                                                                        100%  293KB   1.5MB/s   00:00    
debug2: channel 0: read<=0 rfd 4 len 0
debug2: channel 0: read failed
debug2: chan_shutdown_read: channel 0: (i0 o0 sock -1 wfd 4 efd 6 [write])
debug2: channel 0: input open -> drain
debug2: channel 0: ibuf empty
debug2: channel 0: send eof
debug2: channel 0: input drain -> closed
debug2: channel 0: rcvd ext data 24
500-Invalid config file

I need to read the 500-Invalid config file output to validate whether the config push was successful or not.

I tried playing around with reading from self.channel.makefile() and self.channel.makefile_stderr() and with self.channel.recv(), but had no success at all.

@remram44 Do you have any idea how I could achieve this?

The text was updated successfully, but these errors were encountered:

remram44 · 2023-05-15T21:12:04Z

scp is supposed to show those, see _recv_confirm(). Do you get a different error?

Yannik · 2023-05-15T21:15:25Z

@remram44 I get no errors at all, unfortunately.

Printing the msg in _recv_confirm() like this:

    def _recv_confirm(self):
        # read scp response
        msg = b''
        try:
            msg = self.channel.recv(512)
            print(msg)

shows

b'\x00'
b'\x00'
b'\x00'

remram44 · 2023-05-15T21:18:34Z

You mean that the transfer succeeds either way (scp returns 0) but it prints this message?

You can try scp.channel.recv_stderr()

Yannik · 2023-05-15T21:25:52Z

openssh scp indeed has an 0 exit code. (even though the error message is printed)

Calling scp.channel.recv_stderr() where scp is a SCPClient results in an AttributeError: 'NoneType' object has no attribute 'recv_stderr', presumably because putting a file closes the channel.

Modifying putfo directly to call print(scp.channel.recv_stderr(512)) after the self._send_file(fl, remote_path, mode, size=size) line results in a timeout error.

Yannik · 2023-05-15T21:29:11Z

@remram44 the same (TimeoutError) occurs when calling self.channel.recv(512) instead of scp.channel.recv_stderr(512).

I have tried to sleep for a few seconds before calling these to make sure the other side had time to send the message, but that did not result in any change either.

remram44 · 2023-05-15T21:39:02Z

Ok I don't know how this message is sent then, sorry.

remram44 added enhancement help wanted labels May 15, 2023

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Retrieve scp errors #180

Retrieve scp errors #180

Retrieve scp errors #180

Retrieve scp errors #180

Comments