scp through jump server with password, destination authenticated with private key

Question

Sitting on host A, connecting to jump server B with password, and then with private key (no password) to server C - from where I want to copy file to host A. Using:

scp -oProxyJump=user1@serverB jump:"/home/user2/file.txt" /home/user1/Desktop/

is not working. It asks for password to jump server B, and then I get:

..
..
debug1: Authentications that can continue: publickey,keyboard-interactive
debug1: Next authentication method: publickey
debug1: Trying private key: /home/user1/.ssh/id_rsa
debug1: Trying private key: /home/user1/.ssh/id_dsa
debug1: Trying private key: /home/user1/.ssh/id_ecdsa
debug1: Trying private key: /home/user1/.ssh/id_ed25519
debug1: Next authentication method: keyboard-interactive
debug1: Authentications that can continue: publickey,keyboard-interactive
debug1: No more authentication methods to try.
Permission denied (publickey,keyboard-interactive).

Obviously problem is that scp is trying to use keys from host A, instead of jump server B, where they are. Is there a way how to tell scp to use authentication keys on jump server instead of local ? Maybe something with : ?

scp -o IdentityFile

It'd be nice not to use ssh config files, just commands with options

Answer 1

I don't think there is: When using ProxyJump, the SSH/SCP client on host A will tunnel through server B, meaning no SSH/SCP client will be executed on server B, thus no easy way to use the private key on host B.

Depending on your requirements, this might be a solution:

ssh serverB ssh jump cat /home/user2/file.txt > /home/user1/Desktop/file.txt