sshfs randomly corrupts files

[Martin]

/usr/bin/sshfs the way it is packaged now is broken, tested on 20.04 focal and 21.10 impish.

This issue is not present on Debian Sid or Arch Linux.

The way the issue shows is that majority of the time, a 40MB .zip file I download from an SFTP server is broken. The stat is identical, filesize is identical to the byte, but the inside is a garbled mess that refuses to unzip anymore. Tested via (and almost always getting a random checksum):

  md5sum /mnt/file.zip && umount /mnt/sftp && mount /mnt/sftp && md5sum /mnt/file.zip

I used a definition in fstab but also manually mounted via 'sshfs -o allow_other,default_permissions'

This is not a kernel issue, this is not a network issue, I have tested in containers and across servers.

Unfortunately, I do not have administrative access to the server I am testing against, so this is the only idea I have about it:

  Remote protocol version 2.0, remote software version CrushFTPSSHD

I was able to work around this on 21.10 by replacing /usr/bin/sshfs binary(and adding an accompanying libfuse3.so to the correct path, probably could've just installed repo version) from Arch Linux.

On 20.04 I installed libfuse3-3 and replaced sshfs with the one in Debian Sid.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.