Error: list: Packet length 49989 exceeds max length of 34000

[ardean]

A folder on a SFTP server does have a lot of files (history of 1 year so far, 340 files). I try to list that folder and i get this error:

Error: list: Packet length 49989 exceeds max length of 34000

If i adjust the max packet size (?) to 100000 it does list my files.

The questions are now:

Why is this limit there?
Update: it is specified as min packet length for servers: https://datatracker.ietf.org/doc/html/draft-ietf-secsh-filexfer-13#section-4

Can I adjust the limit by an option? (not possible as far as I can see)
Is there a better way to implement this?

Can you split the command in separate packets?

-> there could be even more files in this folder

So it makes not really sense to increase the limit. As the limit will be reached sometime again in the future.

Here is the limit that i adjusted on my machine:

ssh2/lib/protocol/SFTP.js

Line 157 in 0af296d

this._maxPktLen = (this._isOpenSSH ? OPENSSH_MAX_PKT_LEN : 34000);

I hope we have a better way to implement this as the folder size should not depend on the packet size.

Thank you for your help

[mscdex]

Does 4606d0e work for you?

[ardean]

Thank you very much @mscdex! Your latest change did the trick. It now works without a problem.

Do you know already when this feature will be available on npm?

[ardean]

It seems fixed and released. Thanks!

[future-mine]

It didn't work for me.

[zxdong262]

Do still exist, when user add something like "source /opt/intel/vtune_amplifier_xe_2013/amplxe-vars.sh" to .bashrc, would ge extra output like

Intel(R) Parallel Studio XE 2019 Update 4 for Linux*

Copyright (C) 2009-2019 Intel Corporation. All rights reserved.

when read data length from first 4 bytes, would get a wrong length exceed max length, I think other sftp client would just ignore these data.

Code should be in

ssh2/lib/protocol/SFTP.js

Line 207 in a56e70e

if (this._pktLenBytes < 4) {

@mscdex

[mscdex]

@zxdong262 There's nothing that can be done in that situation because SFTP is completely binary in nature so there is no way any (generic) SFTP client could reliably ignore any such data.

Besides, most bashrc scripts exit immediately when they detect a non-interactive mode.

[zxdong262]

@zxdong262 There's nothing that can be done in that situation because SFTP is completely binary in nature so there is no way any (generic) SFTP client could reliably ignore any such data.

Besides, most bashrc scripts exit immediately when they detect a non-interactive mode.

How about ignore length seems impossible like 1349281121(or set a impossible const to compare) intead of throw error? Is that safe or right thing to do?

[mscdex]

Is that safe or right thing to do?

It's not safe.