Error if I use scp from same network with python paramiko

[q000p]

If I run python script with scp from dropbear host from same subnet (without gateway) I have error Channel closed. If I use gateway or if I use v2020.79 of dropbear, the problem is absent. Paramiko log attached paramerror.log

[q000p]

Logs from dropbear: root@Decode:~# dropbear -F -E [18096] Nov 13 14:48:32 Failed loading /etc/dropbear/dropbear_rsa_host_key [18096] Nov 13 14:48:32 Failed loading /etc/dropbear/dropbear_dss_host_key [18096] Nov 13 14:48:32 Not backgrounding [18111] Nov 13 14:48:36 Child connection from 192.168.221.120:45278 [18111] Nov 13 14:48:44 Password auth succeeded for 'root' from 192.168.221.120:45278 [18111] Nov 13 14:48:45 Exit (root) from <192.168.221.120:45278>: Failed assertion (common-channel.c:705): `!channel->sent_close' [18096] Nov 13 14:53:19 Early exit: Terminated by signal

[mkj]

Thanks for the Dropbear log, I'll have a look (might be a bit delayed)

[richardash1981]

I'm having similar issues to this and/or #220:

• Local (switched gigabit ethernet) connection between PC running Python/Paramiko client and embedded dropbear server.
• Paramiko receives (somewhat at random) "Channel closed" exceptions - paramiko.ssh_exception.SSHException: Channel closed.
• Paramiko is being used to establish one session, and then run a succession of exec_command commands via channels. Usually the first few (the number varies) of these succeed, then a subsequent one fails with the above exception (at which point the session is closed).

Dropbear logs are very weird. When there is an exception, dropbear logs:

Oct  1 13:17:46 EA_VNH1 authpriv.info dropbear[8384]: Child connection from 192.168.0.153:33520
Oct  1 13:17:47 EA_VNH1 authpriv.notice dropbear[8384]: Pubkey auth succeeded for 'root' with ssh-rsa key SHA256:JbHcJycuOViQaJdGr7WPrKR1clJqC6ypWAd0UTcPvZs from 192.168.0.153:33520
Oct  1 13:17:47 EA_VNH1 authpriv.info dropbear[8384]: Exit (root) from <192.168.0.153:33520>: Exited normally

OK, but on the rare case where the script completes without an error (all the commands succeed), the dropbear logs are:

Oct  1 13:17:57 EA_VNH1 authpriv.info dropbear[8435]: Child connection from 192.168.0.153:46340
Oct  1 13:17:57 EA_VNH1 authpriv.notice dropbear[8435]: Pubkey auth succeeded for 'root' with ssh-rsa key SHA256:JbHcJycuOViQaJdGr7WPrKR1clJqC6ypWAd0UTcPvZs from 192.168.0.153:46340
Oct  1 13:17:58 EA_VNH1 authpriv.info dropbear[8435]: Exit (root) from <192.168.0.153:46340>: Error reading: Connection reset by peer

The errors seem to be inverted (I did check order and timings, and get lots more failed runs than successful ones).

Versions: paramiko==3.5.0 from pip Python 3.12.3 on x86_64 Linux. dropbear-2022.83 from buildroot 2023.02.6 on arm32v7l