Hi there,
I have problems activating SSH keys on OpenWRT 21.02. With
ssh-keygen -t ECDSA -f openwrt_ecdsa
I have created on the SSH client for SSH login and using
cat ~/.ssh/openwrt_ecdsa.pub | ssh -p 22 root@192.168.0.1 'umask 077; cat >>.ssh/authorized_keys'
transferred to the router.
In the LUCI portal I entered the public key of openwrt_ecdsa under System=>Administration=>SSH-Keys.
If I now run
ssh -vvv -i ~/.ssh/openwrt_ecdsa root@192.168.0.1
from the client I get no connection:
OpenSSH_8.4p1 Debian-5, OpenSSL 1.1.1k 25 Mar 2021
debug1: Reading configuration data /home/diani/.ssh/config
debug1: /home/diani/.ssh/config line 1: Applying options for *
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: include /etc/ssh/ssh_config.d/*.conf matched no files
debug1: /etc/ssh/ssh_config line 21: Applying options for *
debug2: resolve_canonicalize: hostname 192.168.0.1 is address
debug3: expanded UserKnownHostsFile '~/.ssh/known_hosts' -> '/home/diani/.ssh/known_hosts'
debug3: expanded UserKnownHostsFile '~/.ssh/known_hosts2' -> '/home/diani/.ssh/known_hosts2'
debug2: ssh_connect_direct
debug1: Connecting to 192.168.0.1 [192.168.0.1] port 22.
debug1: Connection established.
debug1: identity file /home/diani/.ssh/openwrt_ecdsa type 2
debug1: identity file /home/diani/.ssh/openwrt_ecdsa-cert type -1
debug1: Local version string SSH-2.0-OpenSSH_8.4p1 Debian-5
debug1: Remote protocol version 2.0, remote software version dropbear
debug1: no match: dropbear
debug2: fd 3 setting O_NONBLOCK
debug1: Authenticating to 192.168.0.1:22 as 'root'
debug3: hostkeys_foreach: reading file "/home/diani/.ssh/known_hosts"
debug3: record_hostkey: found key type ED25519 in file /home/diani/.ssh/known_hosts:223
debug3: load_hostkeys: loaded 1 keys from 192.168.0.1
debug3: order_hostkeyalgs: prefer hostkeyalgs: ssh-ed25519-cert-v01@openssh.com,ssh-ed25519
debug3: send packet: type 20
debug1: SSH2_MSG_KEXINIT sent
debug3: receive packet: type 20
debug1: SSH2_MSG_KEXINIT received
debug2: local client KEXINIT proposal
debug2: KEX algorithms: curve25519-sha256,curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group14-sha256,ext-info-c
debug2: host key algorithms: ssh-ed25519-cert-v01@openssh.com,ssh-ed25519,ecdsa-sha2-nistp256-cert-v01@openssh.com,ecdsa-sha2-nistp384-cert-v01@openssh.com,ecdsa-sha2-nistp521-cert-v01@openssh.com,sk-ecdsa-sha2-nistp256-cert-v01@openssh.com,sk-ssh-ed25519-cert-v01@openssh.com,rsa-sha2-512-cert-v01@openssh.com,rsa-sha2-256-cert-v01@openssh.com,ssh-rsa-cert-v01@openssh.com,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,sk-ecdsa-sha2-nistp256@openssh.com,sk-ssh-ed25519@openssh.com,rsa-sha2-512,rsa-sha2-256,ssh-rsa
debug2: ciphers ctos: chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com
debug2: ciphers stoc: chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com
debug2: MACs ctos: umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,zlib@openssh.com,zlib
debug2: compression stoc: none,zlib@openssh.com,zlib
debug2: languages ctos:
debug2: languages stoc:
debug2: first_kex_follows 0
debug2: reserved 0
debug2: peer server KEXINIT proposal
debug2: KEX algorithms: curve25519-sha256,curve25519-sha256@libssh.org,diffie-hellman-group14-sha256,diffie-hellman-group14-sha1,kexguess2@matt.ucc.asn.au
debug2: host key algorithms: ssh-ed25519,rsa-sha2-256,ssh-rsa
debug2: ciphers ctos: chacha20-poly1305@openssh.com,aes128-ctr,aes256-ctr
debug2: ciphers stoc: chacha20-poly1305@openssh.com,aes128-ctr,aes256-ctr
debug2: MACs ctos: hmac-sha1,hmac-sha2-256
debug2: MACs stoc: hmac-sha1,hmac-sha2-256
debug2: compression ctos: none
debug2: compression stoc: none
debug2: languages ctos:
debug2: languages stoc:
debug2: first_kex_follows 0
debug2: reserved 0
debug1: kex: algorithm: curve25519-sha256
debug1: kex: host key algorithm: ssh-ed25519
debug1: kex: server->client cipher: chacha20-poly1305@openssh.com MAC: <implicit> compression: none
debug1: kex: client->server cipher: chacha20-poly1305@openssh.com MAC: <implicit> compression: none
debug3: send packet: type 30
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug3: receive packet: type 31
debug1: Server host key: ssh-ed25519 SHA256:9pP5YZHLc0+dV1i7Z9WYirEfGFKbAT4xkRhj0LdgZGk
debug3: hostkeys_foreach: reading file "/home/diani/.ssh/known_hosts"
debug3: record_hostkey: found key type ED25519 in file /home/diani/.ssh/known_hosts:223
debug3: load_hostkeys: loaded 1 keys from 192.168.0.1
debug1: Host '192.168.0.1' is known and matches the ED25519 host key.
debug1: Found key in /home/diani/.ssh/known_hosts:223
debug3: send packet: type 21
debug2: set_newkeys: mode 1
debug1: rekey out after 134217728 blocks
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug3: receive packet: type 21
debug1: SSH2_MSG_NEWKEYS received
debug2: set_newkeys: mode 0
debug1: rekey in after 134217728 blocks
debug1: Will attempt key: /home/diani/.ssh/openwrt_ecdsa ECDSA SHA256:+3/Zz2oVUxfqW9DCYw0eEvWTYWFrTw/i39kJ7/tMZJE explicit
debug2: pubkey_prepare: done
debug3: send packet: type 5
debug3: receive packet: type 7
debug1: SSH2_MSG_EXT_INFO received
debug1: kex_input_ext_info: server-sig-algs=<ssh-ed25519,rsa-sha2-256,ssh-rsa>
debug3: receive packet: type 6
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug3: send packet: type 50
debug3: receive packet: type 51
debug1: Authentications that can continue: publickey
debug3: start over, passed a different list publickey
debug3: preferred gssapi-with-mic,publickey,keyboard-interactive,password
debug3: authmethod_lookup publickey
debug3: remaining preferred: keyboard-interactive,password
debug3: authmethod_is_enabled publickey
debug1: Next authentication method: publickey
debug1: Offering public key: /home/diani/.ssh/openwrt_ecdsa ECDSA SHA256:+3/Zz2oVUxfqW9DCYw0eEvWTYWFrTw/i39kJ7/tMZJE explicit
debug3: send packet: type 50
debug2: we sent a publickey packet, wait for reply
debug3: receive packet: type 51
debug1: Authentications that can continue: publickey
debug2: we did not send a packet, disable method
debug1: No more authentication methods to try.
root@192.168.0.1: Permission denied (publickey).
Curiously, I had already installed an SSH key for a client on a VPN tunnel (vpn0). And this SSH login towards router works fine.
Another point is to limit SSH access to individual interfaces. This is currently set to "unspecified". I do not like it. But a restriction to the interfaces "vpn0", "home", "office" fails. Access via ssh is then no longer possible.
What am I doing wrong right now?
Best regards
Diani