使用 ssh 密钥进行多用户登录的 AWS ec2 实例不起作用

Question

I have a server(ubuntu16.04) in aws ec2. And I have a private key to access the server. The origin user I used called ubuntu which is generated by aws. Now my client B wants to login server to synchronize(it's a window10 pc). I don't want to use my aws private key in different places. So I create a new user which has a limited right called syncusr .

$ cat /etc/passwd
syncusr:x:1002:1002::/home/syncusr:

I generated ssh-key (ssh-keygen) then append public key to authorized_keys in ~/.ssh

$ ls -ld ~/.ssh; ls -l ~/.ssh
drwx------ 2 syncusr syncusr 4096 May 15 12:14 /home/syncusr/.ssh
total 8
-rw-r--r-- 1 syncusr syncusr  404 May 15 12:13 authorized_keys
-rwxrwxrwx 1 syncusr syncusr 1679 May 15 12:13 id_rsa

Now I download id_rsa and run PuTTYgen got a private key, then I login from client B with username syncusr and private key but failed.

. 2020-05-15 12:17:00.335 Initialised AES-256 SDCTR (AES-NI accelerated) outbound encryption
. 2020-05-15 12:17:00.335 Initialised HMAC-SHA-256 outbound MAC algorithm
. 2020-05-15 12:17:00.335 Initialised AES-256 SDCTR (AES-NI accelerated) inbound encryption
. 2020-05-15 12:17:00.335 Initialised HMAC-SHA-256 inbound MAC algorithm
. 2020-05-15 12:17:00.507 Reading key file "D:\SSHKEY\private_key.ppk"
! 2020-05-15 12:17:00.507 Using username "syncusr".
. 2020-05-15 12:17:00.709 Server offered these authentication methods: publickey
. 2020-05-15 12:17:00.709 Offered public key
! 2020-05-15 12:17:00.901 Server refused our key
. 2020-05-15 12:17:00.918 Server refused our key
. 2020-05-15 12:17:00.918 Server offered these authentication methods: publickey
. 2020-05-15 12:17:00.918 No supported authentication methods available (server sent: publickey)
. 2020-05-15 12:17:00.918 Attempt to close connection due to fatal exception:
* 2020-05-15 12:17:00.918 No supported authentication methods available (server sent: publickey)

which part did I miss?

Answer 1

Set your authorized_keys file to 600 permission.

Also as an FYI id_rsa should be 400 permission (but not relevant to this question).