The key algorithm 'ssh-rsa' is not allowed in V 0.10.4

[g4-lisz@xxxxxxxxxxxx]

Hi there,

I wrote a client (TCP forwarding) that connects to a server which uses libssh V 0.9.7.

When I compile the client with 0.9.6 (this is what I get with libssh-dev on Pop!_OS 22.04) then all works fine.

However, on RHEL9, libssh-dev brings v0.10.4. And compiled with that version the client can't connect anymore:

 "ssh_userauth_try_publickey: The key algorithm 'ssh-rsa' is not allowed to be used by PUBLICKEY_ACCEPTED_TYPES configuration option"

At first I was confused: Who says this? The server? But it accepted the key when using a client with version 0.9.6.
So I tried to add 'ssh-rsa' to the client's allowed key types:

if (ssh_options_set(session, SSH_OPTIONS_PUBLICKEY_ACCEPTED_TYPES, "+ ssh-rsa") < 0) {
 fprintf(stderr, "ssh_options_set failed: %sn", ssh_get_error(session);
}

ssh_options_set(...) seems to succeed. However, everything else remains the same. The key algorithm 'ssh-rsa' is not allowed to be used...

How can this be solved? What is the right way to convince libssh that it can use public keys of type ssh-rsa?

The remote account only knows my ssh-rsa public key and this can't be changed easily. That's why I have to stick with that type...

Cheers
Till