Permissions on private key in .ssh folder?

Question

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

Solution 1

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.

Solution 2

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 [email protected]

Solution 3

Am posting this as a separate answer since I wanted to see man page recommendations translated into permissions.

Summary based on the man page quotes (linked at the end):

Directory or File	Man Page	Recommended Permissions	Mandatory Permissions
~/.ssh/	There is no general requirement to keep the entire contents of this directory secret, but the recommended permissions are read/write/execute for the user, and not accessible by others.	700
~/.ssh/authorized_keys	This file is not highly sensitive, but the recommended permissions are read/write for the user, and not accessible by others	600
~/.ssh/config	Because of the potential for abuse, this file must have strict permissions: read/write for the user, and not accessible by others. It may be group-writable, provided that the group in question contains only the user.		600
~/.ssh/identity ~/.ssh/id_dsa ~/.ssh/id_rsa	These files contain sensitive data and should be readable by the user but not accessible by others (read/write/execute)		600
~/.ssh/identity.pub ~/.ssh/id_dsa.pub ~/.ssh/id_rsa.pub	Contains the public key for authentication. These files are not sensitive and can (but need not) be readable by anyone.	644

All the man page quotes are from http://linuxcommand.org/lc3_man_pages/ssh1.html

Solution 4

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

chmod g-w,o-w ~

Solution 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.

View more solutions

Comments

[Akhil]

#!/bin/bash find .ssh/ -type f -exec chmod 600 {} \;; find .ssh/ -type d -exec chmod 700 {} \;; find .ssh/ -type f -name "*.pub" -exec chmod 644 {} \;

[ThaJay]

Thank you @AkhilJalagam, your code just saved me some thinking. I love stuff like that. I know how to do it but why should I if it's already here :D

[user215505]

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.

[Job AJ]

I found elsewhere that if using the authorized_keys file, that it should be chmod'd to 640, ie -rw-r----- .

[Sonique]

Where I can find this info in man pages?

[JREAM]

I have come back to this post about 30 times now. I cant believe I cant remember it.

[Alex W]

Do not underestimate permissions. They definitely still come into play.

[cdhowie]

@AlexW They do come into play with other aspects of ssh, but not the one asked about in the question.

[Alex W]

FYI, this command assumes you are logged in as the user and not root

[Markus Kuhn]

You can also safely leave the .ssh directory permissions at 755 (drwxr-xr-x), as well as the id_*.pub and authorized_keys permissions at 644 (-rw-r--r--). Otherwise other users cannot lookup your public keys, but being able to do so is often convenient if they need to know your public keys to grant you access to some service.

[Markus Kuhn]

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.

[Michael Millar]

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. [email protected]). I just had to make sure the local user owned the local .ssh files (e.g. abc:abc, not root:abc)`

[nerdoc]

If you have no password on private keys (whink of automated remote called scripts), it won't help you. Permissions are necessary here.

[augurar]

@MarkusKuhn OpenSSH specifies 600 for authorized_keys for some reason (link).

[Nav]

Thanks for putting all the steps and commands for newbies, Alex. Yours is one of the most helpful answers here.

[Alan Robinson]

@augurar My guess: a world-readable authorized_keys file would expose the (public) keys that an attacker could use to gain full access to your account. They'd still need to find one of the private keys, of course.

[Alan Robinson]

To let others verify your signatures and encrypt files for you, make the public key files (*.pub) world-readable and the .ssh folder world-readable and -executable. Without the latter, other users won't be able to view the public key files.

[Cerin]

Why 700? Why would you need anything under ~/.ssh to be executable?

[xtian]

Why, after generated, would private key be writeable (600)? Generate the keys, then lock down the folder, no?

[Florian Brucker]

The correct permissions for ~/.ssh/config are 600.

[Thomas]

@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.

[Le Quoc Viet]

+1. "Authorized_keys file needs 644 permissions" <= that was crucial!

[Adam Glauser]

At least some versions of OpenSSH require home directory permissions such that only the user can write the home directory. Otherwise, ~/.ssh could be replaced by a link, and an arbitrary authorized_keys file substituted.

[user3125367]

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.

[Craig Hicks]

"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?"

[A T]

400 for the pem files are sufficient in my experience.

[Akito]

I get Permissions 0644 for '/home/user/.ssh/id_rsa.pub' are too open. on Debian Buster.

[Lloyd Dewolf]

This answer cannot be correct as the directory is more restrictive than the public key.

[Weltraumschaf]

As @Akito mentioned it makes no sense to give id_rsa.pub 0644 if the parent dir has 0700 nobody else than the owner can access the file.

[juliangonzalez]

664 will raise a WARNING: UNPROTECTED PRIVATE KEY FILE! with a Permissions 0644 for 'varys-new.pem' are too open. Use 600 instead.

[James Bond]

JREAM, this is because you don't try to write this numbers yourself) You are afraid to make a mistake. But when you will try to call to mind some numbers without prompts, quite possibly you will make a mistake, but an the next you will remember information strongly. You SHOULD make a mistake. This is a way to remember. This is how a human brain works)

[xtian]

Let's not forget known_hosts > "~/.ssh/known_hosts Contains a list of host keys for all hosts the user has logged into that are not already in the systemwide list of known host keys. [...] This file should be writable only by root/the owner and can, but need not be, world-readable." (linux.die.net/man/8/sshd)

[Dmitry Gusarov]

Thank you! Saved my life... Stupid me, copied authorized_keys file from user to root. Your post helped me figure out that I need chown root:root authorized_keys. That was the solution for me

[Alan]

What about 440 for the private key(id_rsa)? There is a group of 'n' users - which is same person but different accounts so x4x should be fine? Also, the private key doesn't have to be modified so why setting 6xx?