CentOS 6.4: SSH RSA key issue, "[...]== rsa-key-20140711\n failed"

Question

For some reason sshd is reading from my authorized_keys file a new line that does not exist. I generated the keys with puttygen, copied the public key text in as required, concatenated the key into one long string starting with ssh-rsa and according to Vi and nano, there are no extra lines.

However, from my secure log, every time I try to use this it's a problem. I get the trying to get more bytes than in buffer error as well as error: key_from_blob: can't read rsa key then the rest of the error which shows the \n after the key comment. It will also do \n even if I remove the comment.

Any ideas what is the problem?

Answer 1

When copying keys into your $HOME/.ssh/authorized_keys file you have to make sure that the the string pasted is one continuous string with no breaks whatsoever.

I typically will open this file in vim and make sure that the strings are correct. They should appear as such:

ssh-dss ....key1.... root@someserver1.com
ssh-dss ....key2.... root@someserver2.com

You can also use this command to confirm that your keys contained in your $HOME/.ssh/authorized_keys file are correct like so:

$ while read line;do ssh-keygen -lf /dev/stdin <<<$line; 
    done <~/.ssh/authorized_keys 
1024 ....fingerprint #1....  root@someserver1 (DSA)
2048 ....fingerprint #2....  user@someserver2 (RSA)
2048 ....fingerprint #3....  user@someserver3 (RSA)

NOTE: The "fingerprints" above are of the form: "1c:ea:12:ef:ab:0a:12:c3:12:55:33:ad:98:55:33:ac", for example.