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I changed my permissions in my .ssh folder and now when I use a piece of software that uses my private key, I have to type my password each time. What should my permissions be on my id_rsa file to not have to type a password each time I use an app that uses it?

Currently my permissions are set to:

-rw-------@ 1 Jody  staff   114 Nov  4 23:29 config
-rw-------  1 Jody  staff  1743 Oct 21  2009 id_rsa
-rw-------@ 1 Jody  staff   397 Oct 21  2009 id_rsa.pub 
-rw-------@ 1 Jody  staff  3855 Sep 13 22:35 known_hosts
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528

Typically you want the permissions to be:

  • .ssh directory: 700 (drwx------)
  • public key (.pub file): 644 (-rw-r--r--)
  • private key (id_rsa): 600 (-rw-------)
  • lastly your home directory should not be writeable by the group or others (at most 755 (drwxr-xr-x)).

I am assuming that you mean that you have to enter your system/user password each time, and that previously you did not have to. cdhowie's response is assuming you set a password/passphrase when generating your keys, and if you did then as he says you will have to enter your password every time unless you use an ssh agent.

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  • 10
    I found elsewhere that if using the authorized_keys file, that it should be chmod'd to 640, ie -rw-r----- . – AnneTheAgile Sep 11 '14 at 21:19
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    Where I can find this info in man pages? – Sonique Nov 17 '14 at 15:56
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    I have come back to this post about 30 times now. I cant believe I cant remember it. – JREAM Apr 2 '15 at 21:35
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    The only important things are that nothing in .ssh is writeable to anyone else and none of the secret keys are readable to anyone else. – Markus Kuhn Sep 30 '15 at 11:56
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    @Cerin execute permission on a directory grants the ability to list immediate child files/dirs of that directory, files inside the folder don't "inherit" the execute bit of their parent folder. – Thomas Jan 29 '17 at 8:42
72

I was struggling with this forever and finally figured out what is needed. Replace $USER everywhere with the SSH username you want to log into on the server. If you're trying to login as root you would need to use /root/.ssh etc., instead of /home/root/.ssh which is how it is for non-root users.

  • Home directory on the server should not be writable by others: chmod go-w /home/$USER
  • SSH folder on the server needs 700 permissions: chmod 700 /home/$USER/.ssh
  • Authorized_keys file needs 644 permissions: chmod 644 /home/$USER/.ssh/authorized_keys
  • Make sure that user owns the files/folders and not root: chown user:user authorized_keys and chown user:user /home/$USER/.ssh
  • Put the generated public key (from ssh-keygen) in the user's authorized_keys file on the server
  • Make sure that user's home directory is set to what you expect it to be and that it contains the correct .ssh folder that you've been modifying. If not, use usermod -d /home/$USER $USER to fix the issue
  • Finally, restart ssh: service ssh restart
  • Then make sure client has the public key and private key files in the local user's .ssh folder and login: ssh user@host.com
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  • Regarding your first paragraph, I am able to ssh with public/private keys with a user on my local linux box (e.g. abc), different from the user on the remote server (e.g. def@123.456.789). I just had to make sure the local user owned the local .ssh files (e.g. abc:abc, not root:abc)` – Michael Dec 22 '15 at 9:41
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    Thanks for putting all the steps and commands for newbies, Alex. Yours is one of the most helpful answers here. – Nav Mar 4 '16 at 6:06
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    +1. "Authorized_keys file needs 644 permissions" <= that was crucial! – Le Quoc Viet Jun 4 '17 at 17:46
  • If you're giving .ssh directory 700 mode, then there is no point in giving r-- to group and others, because only you can "go through" .ssh then (assuming no hard links exists for these files). The same for accepted answer. Default 755 is enough. – user3125367 Aug 21 '17 at 9:39
  • 400 for the pem files are sufficient in my experience. – A T Nov 14 '18 at 12:24
34

Also ensure that your home directory is not writeable by other users.

chmod g-w,o-w ~

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  • 6
    FYI, this command assumes you are logged in as the user and not root – Alex W Jun 9 '15 at 18:40
5

Permissions shouldn't have anything to do with this. Your private key is encrypted with the password, so you need to enter it for the private key to be decrypted and usable.

You might consider running an ssh agent, which can cache decrypted keys and will supply them to applications that need them.

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  • Thanks for the additional info about the ssh agent. Looks like there is one built into Leopard so I think I'll do that. Having a bit of trouble with it but I'll ask another question. – Jody G Nov 26 '10 at 22:18
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    Do not underestimate permissions. They definitely still come into play. – Alex W May 15 '15 at 19:49
  • @AlexW They do come into play with other aspects of ssh, but not the one asked about in the question. – cdhowie May 24 '15 at 23:43
  • If you have no password on private keys (whink of automated remote called scripts), it won't help you. Permissions are necessary here. – nerdoc Jan 7 '16 at 23:13
  • "I have to type my password each time. What should my permissions be on my id_rsa file to not have to type a password each time I use an app that uses it?" – Craig Hicks Oct 8 '18 at 3:11
4

Felipe is correct -- the directory containing your .ssh directory must not be writeable by group or other. Thus chmod go-w ~ is the next logical thing to try if you are still prompted for a password when ssh'ing after running ssh-keygen -t rsa; cp ~/.ssh/id_rsa.pub ~/.ssh/authorized_keys, assuming you don't assign a passphrase in the ssh-keygen command, and your .ssh directory is in your home directory.

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protected by JakeGould Dec 17 '15 at 4:57

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