# ssh troubleshooting ---- **This document must be read in full the first time. If you start from some nice looking section in the middle it may not help you unless you're already an expert at ssh**. In this document: * IMPORTANT -- READ THIS FIRST * caveats * naming conventions used * taking stock -- relevant files and directories * normal gitolite key handling * (Other resources) * common problems * step by step * random tips, tricks, and notes * giving shell access to gitolite users * losing your admin key * simulating ssh-copy-id * problems with using non-openssh public keys * windows issues * appendix 1: ssh daemon asks for a password * appendix 2: which key is which -- running sshkeys-lint * typical cause(s) * appendix 3: ssh client may not be offering the right key * appendix 4: host aliases * appendix 5: why bypassing gitolite causes a problem ---- This document should help you troubleshoot ssh-related problems in installing and accessing gitolite. ### IMPORTANT -- READ THIS FIRST #### caveats * Before reading this document, it is **mandatory** to read and **completely understand** [doc/gitolite-and-ssh.mkd][doc9gas], which is a very detailed look at how gitolite uses ssh's features on the server side. Don't assume you know all that; if you knew it, you wouldn't be needing *this* document either! * This document, and others linked from this, together comprise all the help I can give you in terms of the ssh aspect of using gitolite. If you're installing gitolite, you're a "system admin", like it or not. Ssh is therefore a necessary skill. Please take the time to learn at least enough to get passwordless access working. * Please note that authentication is not really gitolite's job at all. I'd rather spend time on actual gitolite features, code, and documentation than authentication (i.e., ssh, in the common case). Surprised? [This][wo] might help explain better. ---- #### naming conventions used * Your workstation is the **client**. Your userid on the client does not matter, and it has no relation to your gitolite username. * the server is called **server** and the "hosting user" is **git**. If this is an RPM/DEB install, the hosting user is probably called "gitolite", however we will use "git" in this document. #### taking stock -- relevant files and directories * the client has a `~/.ssh` containing a few keypairs. It may also have a `config` file. * the client also has a clone of the "gitolite-admin" repo, which contains a bunch of `*.pub` files in `keydir`. We assume this clone is in `$HOME`; if it is not, adjust instructions accordingly when needed. * The git user on the server has a `~/.ssh/authorized_keys` file that the ssh daemon uses to authenticate incoming users. We often call this file **authkeys** to save typing, and it always means the one on the server (we're not interested in this file on the client side). * the server also has a `~/.gitolite/keydir` which contains a bunch of `*.pub` files. #### normal gitolite key handling Here's how normal gitolite key handling works: * (on client) pub key changes like adding new ones, deleting old ones, etc., are done in the `keydir` directory in the gitolite-admin repo clone. Then the admin `git add`s and `git commit`s those changes, then `git push`es them to the server. * (on server) a successful push from the client makes git invoke the post-update hook in the gitolite-admin repo. This hook is installed by gitolite, and it does a bunch of things which are quite transparent to the admin, but we'll describe briefly here: * the pubkey files from this push are checked-out into `~/.gitolite/keydir` (and similarly the config files into `~/.gitolite/conf`) * the "compile" script then runs, which uses these files to populate `~/.ssh/authorized_keys` on the server The authkeys file may have other, (non-gitolite) keys also. Those lines are preserved. Gitolite only touches lines that are found between gitolite's "marker" lines (`# gitolite start` and `# gitolite end`). ### (Other resources) People who think installing gitolite is too hard should take a look at this [tutorial][tut] to **see how simple it *actually* is**. ### common problems Since I'm pretty sure at least some of you didn't bother to read the "IMPORTANT: PLEASE READ FIRST" section above, let me take a minute to point you there again. Especially the first bullet. Done? OK, read on... The following problem(s) indicate that pubkey access is not working at all, so you should start with appendix 1. If that doesn't fix the problem, continue with the other appendices in sequence. * running any git clone/fetch/ls-remote or just `ssh git@server info` asks you for a password. The following problem(s) indicate that your pubkey is bypassing gitolite and going straight to a shell. You should start with appendix 2 and continue with the rest in sequence. Appendix 5 has some background info. * running `ssh git@server info` gets you the output of the GNU 'info' command instead of gitolite's version and access info. * running `git clone git@server:repositories/reponame` (note presence of `repositories/` in URL) works. [A proper gitolite key will only let you `git clone git@server:reponame` (note absence of `repositories/`)] * you are able to clone repositories but are unable to push changes back (the error complains about the `GL_RC` environment variable not being set, and the `hooks/update` failing in some way). [If you run `git remote -v` you will find that your clone URL included the `repositories/` described above!] * conversely, using the correct syntax, `git clone git@server:reponame` (note absence of `repositories/` in the URL), gets you `fatal: 'reponame' does not appear to be a git repository`, and yet you are sure 'reponame' exists, you haven't mis-spelled it, etc. ### step by step Since I'm pretty sure at least some of you didn't bother to read the "IMPORTANT: PLEASE READ FIRST" section above, let me take a minute to point you there again. Especially the first bullet. Done? OK, now the general outline for ssh troubleshooting is this: * make sure the server's overall setup even *allows* pubkey based login. I.e., check that git fetch/clone/ls-remote commands or a plain `ssh git@server info` do NOT ask for a password. If you do get asked for a password, see appendix 1. * match client-side pubkeys (`~/.ssh/*.pub`) with the server's authkeys file. To do this, run `sshkeys-lint`, which tells you in detail what key has what access. See appendix 2. * at this point, we know that we have the right key, and that if sshd receives that key, things will work. But we're not done yet. We still need to make sure that this specific key is being offered/sent by the client, instead of the default key. See appendix 3 and 4. ### random tips, tricks, and notes #### giving shell access to gitolite users We've managed (thanks to an idea from Jesse Keating) to make it possible for a single key to allow both gitolite access *and* shell access. This is done by copying the pubkey (to which you want to give shell access) to the server and running gl-tool add-shell-user ~/foo.pub **IMPORTANT UPGRADE NOTE**: previous implementations of this feature were crap. There was no easy/elegant way to ensure that someone who had repo admin access would not manage to get himself shell access. Giving someone shell access requires that you should have shell access in the first place, so the simplest way is to enable it from the server side only. #### losing your admin key If you lost the admin key, and need to re-establish ownership of the gitolite-admin repository with a fresh key, get a shell on the server and use the program called `gl-admin-push` that comes with gitolite. See instructions [here][gssp]. [gssp]: http://sitaramc.github.com/gitolite/doc/3-faq-tips-etc.html#_gl_admin_push_bypassing_gitolite_for_the_gitolite_admin_repo #### simulating ssh-copy-id don't have `ssh-copy-id`? This is broadly what that command does, if you want to replicate it manually. The input is your pubkey, typically `~/.ssh/id_rsa.pub` from your client/workstation. * it copies it to the server as some file * it appends that file to `~/.ssh/authorized_keys` on the server (creating it if it doesn't already exist) * it then makes sure that all these files/directories have go-w perms set (assuming user is "git"): /home/git/.ssh/authorized_keys /home/git/.ssh /home/git [Actually, `sshd` requires that even directories *above* `~` (`/`, `/home`, typically) also must be `go-w`, but that needs root. And typically they're already set that way anyway. (Or if they're not, you've got bigger problems than gitolite install not working!)] #### problems with using non-openssh public keys Gitolite accepts public keys only in openssh format. Trying to use an "ssh2" key (used by proprietary SSH software) results in: WARNING: a pubkey file can only have one line (key); ignoring YourName.pub To convert ssh2-compatible keys to openssh run: ssh-keygen -i -f /tmp/ssh2/YourName.pub > /tmp/openssh/YourName.pub then use the resulting pubkey as you normally would in gitolite. #### windows issues On windows, I have only used msysgit, and the openssh that comes with it. Over time, I have grown to distrust putty/plink due to the number of people who seem to have trouble when those beasts are involved (I myself have never used them for any kind of git access). If you have unusual ssh problems that just don't seem to have any explanation, try removing all traces of putty/plink, including environment variables, etc., and then try again. Thankfully, someone contributed [contrib/putty.mkd][putty]. ---- ### appendix 1: ssh daemon asks for a password > **NOTE**: This section should be useful to anyone trying to get > password-less access working. It is not necessarily specific to gitolite, > so keep that in mind if the wording feels a little more general than you > were expecting. You have generated a keypair on your workstation (`ssh-keygen`) and copied the public part of it (`~/.ssh/id_rsa.pub`, by default) to the server. On the server you have appended this file to `~/.ssh/authorized_keys`. Or you ran something, like the `gl-setup` step during a gitolite install, which should have done that for you. You now expect to log in without having to type in a password, but when you try, you are being asked for a password. This is a quick checklist: * make sure you're being asked for a password and not a pass*phrase*. Do not confuse or mistake a prompt saying `Enter passphrase for key '/home/sitaram/.ssh/id_rsa':` for a password prompt from the remote server! When you create an ssh keypair using `ssh-keygen`, you have the option of protecting it with a passphrase. When you subsequently use that keypair to access a remote host, your *local* ssh client needs to unlock the corresponding private key, and ssh will probably ask for the passphrase you set when you created the keypair. You have two choices to avoid this prompt every time you try to use the private key. The first is to create keypairs *without* a passphrase (just hit enter when prompted for one). **Be sure to add a passphrase later, once everything is working, using `ssh-keygen -p`**. The second is to use `ssh-agent` (or `keychain`, which in turn uses `ssh-agent`) or something like that to manage your keys. Other than discussing one more potential trouble-spot with ssh-agent (see below), further discussion of ssh-agent/keychain is out of scope of this document. * ssh is very sensitive to permissions. An extremely conservative setup is given below, but be sure to do this on **both the client and the server**: cd $HOME chmod go-rwx . chmod -R go-rwx .ssh * actually, every component of the path to `~/.ssh/authorized_keys` all the way upto the root directory must be at least `chmod go-w`. So be sure to check `/` and `/home` also. * while you're doing this, make sure the owner and group info for each of these components are correct. `ls -ald ~ ~/.ssh ~/.ssh/authorized_keys` will tell you what they are. * you may also want to check `/etc/ssh/sshd_config` to see if the "git" user is allowed to login at all. For example, if that file contains an `AllowUsers` config entry, then only users mentioned in that line are allowed to log in! * some OSs/distributions require that the "git" user should have a password and/or not be a locked account. You may want to check that as well. * if all that fails, log onto the server as root, `cd /var/log`, and look for a file called `auth.log` or `secure` or some such name. Look inside this file for messages matching the approximate time of your last attempt to login, to see if they tell you what is the problem. ### appendix 2: which key is which -- running sshkeys-lint Follow these steps on the client: * get a copy of `~/.ssh/authorized_keys` from the server and put it in `/tmp/foo` or something * cd to `~/.ssh` * run `sshkeys-lint /tmp/foo` This checks every `*.pub` file in your `~/.ssh`, in combination with the server's authkeys file. It then tells you which key gets you what type of access (if any) to the server. Note that it is not trying to log in or anything -- it's just comparing bits of text (the contents of `/tmp/foo` and of each of the `*.pub` files). > Note: It's also a stand-alone program, so even if your gitolite version is > old, you can safely bring over just this program from a more recent > gitolite and use it, without having to upgrade gitolite itself. If the pubkey file you're interested in appears to have the correct access to the server, you're done with this step. Otherwise you have to rename some keypairs and try again to get the effect you need. Be careful: * do not just rename the ".pub" file; you will have to rename the corresponding private key also (the one with the same basename but without an extension) * if you're running ssh-agent, you may have to delete (using `ssh-add -D`) and re-add identities for it to pick up the renamed ones correctly #### typical cause(s) The admin often has passwordless shell access to `git@server` already, and then used that same key to get access to gitolite (i.e., copied that same pubkey as YourName.pub and ran `gl-setup` on it). As a result, the same key appears twice in the authkeys file now, and since the ssh server will always use the first match, the second occurrence (which invokes gitolite) is ignored. To fix this, you have to use a different keypair for gitolite access. The best way to do this is to create a new keypair, copy the pubkey to the server as YourName.pub, then run `gl-setup YourName.pub` on the server. Remember to adjust your agent identities using ssh-add -D and ssh-add if you're using ssh-agent, otherwise these new keys may not work. ### appendix 3: ssh client may not be offering the right key * make sure the right private key is being offered. Run ssh in very verbose mode and look for the word "Offering", like so: ssh -vvv user@host pwd 2> >(grep -i offer) If some keys *are* being offered, but not the key that was supposed to be used, you may be using ssh-agent (next bullet). You may also need to create some host aliases in `~/.ssh/config` (appendix 4). * (ssh-agent issues) If `ssh-add -l` responds with either "The agent has no identities." or "Could not open a connection to your authentication agent.", then you can skip this bullet. However, if `ssh-add -l` lists *any* keys at all, then something weird happens. Due to a quirk in ssh-agent, ssh will now *only* use one of those keys, *even if you explicitly ask* for some other key to be used. In that case, add the key you want using `ssh-add ~/.ssh/YourName` and try the access again. ### appendix 4: host aliases (or "making git use the right options for ssh") The ssh command has several options for non-default items to be specified. Two common examples are `-p` for the port number if it is not 22, and `-i` for the public key file if you do not want to use just `~/.ssh/id_rsa` or such. Git has two ssh-based URL syntaxes, but neither allows specifying a non-default public key file. And a port number is only allowed in one of them. (See `man git-clone` for details). Finally, hosts often have to be referred with IP addresses (such is life), or the name is very long, or hard to remember. Using a "host" para in `~/.ssh/config` lets you nicely encapsulate all this within ssh and give it a short, easy-to-remember, name. Example: host gitolite user git hostname a.long.server.name.or.annoying.IP.address port 22 identityfile ~/.ssh/id_rsa Now you can simply use the one word `gitolite` (which is the host alias we defined here) and ssh will infer all those details defined under it -- just say `ssh gitolite` and `git clone gitolite:reponame` and things will work. (By the way, the 'port' and 'identityfile' lines are needed only if you have non-default values, although I put them in anyway just to be complete). If you have *more than one* pubkey with access to the *same* server, you **must** use this method to make git pick up the right key. There is no other way to do this, as far as I know. ---- [doc9gas]: http://sitaramc.github.com/gitolite/doc/gitolite-and-ssh.html [install]: http://sitaramc.github.com/gitolite/doc/1-INSTALL.html [o3]: http://sitaramc.github.com/gitolite/doc/1-INSTALL.html#methods [fc]: http://sitaramc.github.com/gitolite/doc/1-INSTALL.html#fc [urls]: http://sitaramc.github.com/gitolite/doc/1-INSTALL.html#URLs_for_gitolite_managed_repos [repout]: http://sitaramc.github.com/gitolite/doc/report-output.html [transcript]: http://sitaramc.github.com/gitolite/doc/install-transcript.html [openssh56]: http://www.openssh.org/txt/release-5.6 [tut]: http://sites.google.com/site/senawario/home/gitolite-tutorial [wo]: http://sitaramc.github.com/gitolite/doc/authentication-vs-authorisation.html [putty]: http://sitaramc.github.com/gitolite/contrib/putty.html ### appendix 5: why bypassing gitolite causes a problem When you bypass gitolite, you end up running your normal shell instead of the special gitolite entry point script `gl-auth-command`. This means commands (like 'info') are interpreted by the shell instead of gitolite. It also means git operations look for repos in `$HOME`. However, gitolite places all your repos in a subdirectory pointed to by `$REPO_BASE` in the rc file (default: `repositories`), and internally prefixes this before calling the actual git command you invoked. Thus, the pathname of the repo that you use on the client is almost never the correct pathname on the server. (This is by design. Don't argue...) This means that, you get 2 kinds of errors if you bypass gitolite * when you use `git@server:reponame` with a key that bypasses gitolite (i.e., gets you a shell), this prefixing does not happen, and so the repo is not found. Neither a clone/fetch nor a push will work. * conversely, consider `git@server:repositories/reponame.git`. The clone operation will work -- you're using the full Unix path, (assuming default `$REPO_BASE` setting), and so the shell finds the repo where you said it would be. However, when you push, gitolite's **update hook** kicks in, and fails to run because some of the environment variables it is expecting are not present.