Linux – SSH with no password (passwordless) on Synology DSM 5 as other (non-root) user

I'm trying to ssh into my Synology disk station without a password (public key authentication), but as non-root.

When I try to ssh as root without password, it works. Following the exact same steps for another user doesn't work. It always asks for password (also, using a password works too).

I have followed every guide out there for this, but I think they're all for DSM 4.x rather than for the new 5.0 version.

SSH debug log

Here's the debug log when I try with -vvv flag:

aether@aether-desktop:~$ ssh -vvv aether@aether-ds.local
OpenSSH_6.2p2 Ubuntu-6ubuntu0.2, OpenSSL 1.0.1e 11 Feb 2013
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug2: ssh_connect: needpriv 0
debug1: Connecting to aether-ds.local [192.168.2.149] port 22.
debug1: Connection established.
debug3: Incorrect RSA1 identifier
debug3: Could not load "/home/aether/.ssh/id_rsa" as a RSA1 public key
debug1: identity file /home/aether/.ssh/id_rsa type 1
debug1: Checking blacklist file /usr/share/ssh/blacklist.RSA-2048
debug1: Checking blacklist file /etc/ssh/blacklist.RSA-2048
debug1: identity file /home/aether/.ssh/id_rsa-cert type -1
debug1: identity file /home/aether/.ssh/id_dsa type -1
debug1: identity file /home/aether/.ssh/id_dsa-cert type -1
debug1: identity file /home/aether/.ssh/id_ecdsa type -1
debug1: identity file /home/aether/.ssh/id_ecdsa-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_6.2p2 Ubuntu-6ubuntu0.2
debug1: Remote protocol version 2.0, remote software version OpenSSH_5.8p1-hpn13v11
debug1: match: OpenSSH_5.8p1-hpn13v11 pat OpenSSH_5*
debug2: fd 3 setting O_NONBLOCK
debug3: load_hostkeys: loading entries for host "aether-ds.local" from file "/home/aether/.ssh/known_hosts"
debug3: load_hostkeys: found key type RSA in file /home/aether/.ssh/known_hosts:1
debug3: load_hostkeys: loaded 1 keys
debug3: order_hostkeyalgs: prefer hostkeyalgs: ssh-rsa-cert-v01@openssh.com,ssh-rsa-cert-v00@openssh.com,ssh-rsa
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug2: kex_parse_kexinit: ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
debug2: kex_parse_kexinit: ssh-rsa-cert-v01@openssh.com,ssh-rsa-cert-v00@openssh.com,ssh-rsa,ecdsa-sha2-nistp256-cert-v01@openssh.com,ecdsa-sha2-nistp384-cert-v01@openssh.com,ecdsa-sha2-nistp521-cert-v01@openssh.com,ssh-dss-cert-v01@openssh.com,ssh-dss-cert-v00@openssh.com,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,ssh-dss
debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-gcm@openssh.com,aes256-gcm@openssh.com,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,rijndael-cbc@lysator.liu.se
debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-gcm@openssh.com,aes256-gcm@openssh.com,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,rijndael-cbc@lysator.liu.se
debug2: kex_parse_kexinit: hmac-md5-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-ripemd160-etm@openssh.com,hmac-sha1-96-etm@openssh.com,hmac-md5-96-etm@openssh.com,hmac-md5,hmac-sha1,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: hmac-md5-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-ripemd160-etm@openssh.com,hmac-sha1-96-etm@openssh.com,hmac-md5-96-etm@openssh.com,hmac-md5,hmac-sha1,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: none,zlib@openssh.com,zlib
debug2: kex_parse_kexinit: none,zlib@openssh.com,zlib
debug2: kex_parse_kexinit: 
debug2: kex_parse_kexinit: 
debug2: kex_parse_kexinit: first_kex_follows 0 
debug2: kex_parse_kexinit: reserved 0 
debug2: kex_parse_kexinit: ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
debug2: kex_parse_kexinit: ssh-rsa,ssh-dss,ecdsa-sha2-nistp256
debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,rijndael-cbc@lysator.liu.se
debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,rijndael-cbc@lysator.liu.se
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,umac-64@openssh.com,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,umac-64@openssh.com,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: none,zlib@openssh.com
debug2: kex_parse_kexinit: none,zlib@openssh.com
debug2: kex_parse_kexinit: 
debug2: kex_parse_kexinit: 
debug2: kex_parse_kexinit: first_kex_follows 0 
debug2: kex_parse_kexinit: reserved 0 
debug2: mac_setup: found hmac-md5
debug1: kex: server->client aes128-ctr hmac-md5 none
debug2: mac_setup: found hmac-md5
debug1: kex: client->server aes128-ctr hmac-md5 none
debug1: sending SSH2_MSG_KEX_ECDH_INIT
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug1: Server host key: RSA f1:57:47:37:47:d4:5c:cd:a7:a4:5a:9c:a3:e8:1d:13
debug3: load_hostkeys: loading entries for host "aether-ds.local" from file "/home/aether/.ssh/known_hosts"
debug3: load_hostkeys: found key type RSA in file /home/aether/.ssh/known_hosts:1
debug3: load_hostkeys: loaded 1 keys
debug3: load_hostkeys: loading entries for host "192.168.2.149" from file "/home/aether/.ssh/known_hosts"
debug3: load_hostkeys: found key type RSA in file /home/aether/.ssh/known_hosts:2
debug3: load_hostkeys: loaded 1 keys
debug1: Host 'aether-ds.local' is known and matches the RSA host key.
debug1: Found key in /home/aether/.ssh/known_hosts:1
debug1: ssh_rsa_verify: signature correct
debug2: kex_derive_keys
debug2: set_newkeys: mode 1
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug2: set_newkeys: mode 0
debug1: SSH2_MSG_NEWKEYS received
debug1: Roaming not allowed by server
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug2: key: /home/aether/.ssh/id_rsa (0x7f4ee2f47200),
debug2: key: /home/aether/.ssh/id_dsa ((nil)),
debug2: key: /home/aether/.ssh/id_ecdsa ((nil)),
debug1: Authentications that can continue: publickey,password
debug3: start over, passed a different list publickey,password
debug3: preferred gssapi-keyex,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 RSA public key: /home/aether/.ssh/id_rsa
debug3: send_pubkey_test
debug2: we sent a publickey packet, wait for reply
debug1: Authentications that can continue: publickey,password
debug1: Trying private key: /home/aether/.ssh/id_dsa
debug3: no such identity: /home/aether/.ssh/id_dsa: No such file or directory
debug1: Trying private key: /home/aether/.ssh/id_ecdsa
debug3: no such identity: /home/aether/.ssh/id_ecdsa: No such file or directory
debug2: we did not send a packet, disable method
debug3: authmethod_lookup password
debug3: remaining preferred: ,password
debug3: authmethod_is_enabled password
debug1: Next authentication method: password
aether@aether-ds.local's password:

Any help appreciated.

Things I've tried so far

Check /etc/ssh/sshd_config (RSAAuthentication, PubkeyAuthentication, AuthorizedKeysFile).
Check .ssh/* perms and ownership. Tried several combinations.
Check HOME var in ~/.profile.
Restarted sshd via synoservicectl –restart sshd and by restarting whole NAS.

Best Answer

I had the same problem. I run an instance of sshd in debug mode on the DiskStation using "/usr/syno/sbin/sshd -d", then I connect to it using "ssh user@DiskSation -vvv" and I got the debug info on the server:

......

debug1: temporarily_use_uid: 1026/100 (e=0/0)

debug1: trying public key file /var/services/homes/user/.ssh/authorized_keys

debug1: fd 5 clearing O_NONBLOCK

Authentication refused: bad ownership or modes for directory /volume1/homes/user

......

I realized that the home folder needs the right permissions too:

cd /var/services/homes/
chown <username> <username>
chmod 755 <username>

And replace with the actual username, like "user".

Finally, the problem is solved!

SSH debug log

Things I've tried so far

Best Answer

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