"failed to set hostkey preference" error on Debian 11

[coldsource]

Hi,

I'm using libgit2 in a C++ project and since several weeks (I guess after a library upgrade) I get this error while calling git_remote_fetch() :
"failed to set hostkey preference: The requested method(s) are not currently supported"

Project has not changed at all on our side, so I suppose it's an update from libgit2. Might be related to issue 6496 ?

Do you have any solution ? Should I change something on my side or just wait for an upgrade ?

Regards,

[ethomson]

🤔 Not sure yet what the trouble is. What version of libssh2 are you using?

[coldsource]

root@srvdev:~# dpkg -l | grep libgit
ii  libgit2-1.1:amd64                     1.1.0+dfsg.1-4+deb11u1                                        amd64        low-level Git library
ii  libgit2-dev:amd64                     1.1.0+dfsg.1-4+deb11u1                                        amd64        low-level Git library (development files)

[ethomson]

Sorry - to be clear, I'm looking for the version of libssh2 (not libgit2 - fun subtle naming issue there).

[coldsource]

Sorry I misunderstood, here it is :
ii libssh2-1:amd64 1.9.0-2 amd64 SSH2 client-side library
ii libssh2-1-dev:amd64 1.9.0-2 amd64 SSH2 client-side library (development headers)

[ethomson]

I can reproduce this on Debian 11. If I have only ecdsa-sha2-nistp256 entries in my known hosts file (and thus, that's the only method being passed to libssh2_session_method_pref), it fails in this manner.

libssh2_session_method_pref is documented to ignore unknown method, but if there's only one method that's unknown (or presumably if all methods are unknown), it does appear to return METHOD_NOT_SUPPORTED. 🤔

I wonder if we should ignore such errors and let negotiation continue. This is - after all - just setting the preference correct?

/cc @carlosmn

[Qix-]

Getting this on Windows, not sure what the fix is. I'm able to clone and push just fine from cmd.exe, but running my application that works fine under WSL (EDIT: and macos) doesn't otherwise work on the windows end.

failed to set hostkey preference: The requested method(s) are not currently supported; class=Ssh (23)

Not sure how to work around this, unfortunately.

[HaraldValantic]

Getting this error also on Windows 10 and Ubuntu 22.04.
Ignoring METHOD_NOT_SUPPORTED errors seems to work fine as work around for me.