I have a problem while trying to use RSYNC with daemon and SSH connection.
What I wan't to do is simply login to rsync without pass and be able to use the rsync daemon.
Here is my conf file (/etc/rsyncd.conf):
uid = rsync
gid = rsync
[yxz]
path = /home/pierre/xyz
read only = false
auth users = rsync
hosts allow = <myIP>
/home/pierre/xyz has gid wich rsync user can reach.
This is working (but is not using the daemon):
rsync -rzP --stats --ignore-existing --remove-sent-files rsync#mydomain.fr:/home/pierre/xyz/ /media/xyz --include="*.cfg" --exclude="*"
This is not working (using the daemon), but rsync asks me for pass and then says "#ERROR: auth failed on module xyz" because I don't have configure authentification this way :
rsync -rzP --stats --ignore-existing --remove-sent-files rsync://rsync#mydomain.fr/xyz/ /media/xyz --include="*.cfg" --exclude="*"
This is not working (using the daemon):
rsync -rzP -e "ssh -l rsync" --stats --ignore-existing --remove-sent-files rsync://rsync#mydomain.fr/xyz/ /media/xyz --include="*.cfg" --exclude="*"
Here is the error message:
rsync: connection unexpectedly closed (0 bytes received so far) [Receiver]
rsync error: error in rsync protocol data stream (code 12) at io.c(605) [Receiver=3.0.9]
With -v option to the ssh command, it says connection is allowed, so I suppose rsync is the problem, not ssh.
Any idee ?
Thanks for your help :)
Make sure that you stop and disable the rsync system service. E.g. if you are using systemd: systemctl disable --now rsync.
Remove -l rsync from the rsync command
rsync -rzP -e "ssh" --stats --ignore-existing --remove-sent-files rsync://mydomain.fr/xyz/ /media/xyz --include="*.cfg" --exclude="*"
Remove auth users = rsync from rsyncd.conf
I found that if I was not using root, I had to also add use chroot = no in rsyncd.conf.
Great it works, but what sort of authentification is made ?
The connection is authenticated as usual for the ssh command (specifically, the same as ssh mydomain.fr).
This does not involve the system service rsync. Instead it uses SSH to start and communicate with an instance of rsync --server --daemon .. You can see this command being started if you replace -e "ssh" with -e "ssh -v".
The problem with using the system service rsync is that it does not encrypt the network connection, so the network is able to intercept and modify the data in transit. This somewhat defeats the point of using any authentication.
Often this approach is used with a dedicated SSH key, using the command="" option in authorized_keys to restrict it to rsync only. A side-benefit of doing so is that it overrides the command rsync tries to use, so you can force it to use --config=~/rsyncd.conf instead of creating a global /etc/rsyncd.conf. IMO this is useful to avoid confusion IMO. It is good practice because if you create the global config file, there is some risk that you will accidentally run the insecure system service. For example Debian 9 enables the rsync system service by default, and will start it automatically at boot if you have created /etc/rsyncd.conf.
https://gist.github.com/trendels/6582e95012f6c7fc6542
https://indico.cern.ch/event/577279/contributions/2354037/attachments/1366772/2071442/Hepsysman-keeping-in-sync.pdf
https://serverfault.com/questions/6367/cant-get-rsync-to-work-in-daemon-over-ssh-mode
Unusual variant using a dedicated user with a custom shell, instead of command="" / ForceCommand, for some reason: http://mennucc1.debian.net/howto-ssh-rsyncd.html
To use rsync daemon without a password, you should remove auth users line from your config file.
uid = rsync
gid = rsync
[yxz]
path = /home/pierre/xyz
read only = false
hosts allow = <myIP>
After starting the daemon, you can refer the module either using :: syntax or using rsync:// prefix as follows
rsync -rzv rsync#mydomain.fr::xyz/ /media/xyz
rsync -rzv rsync://rsync#mydomain.fr/xyz/ /media/xyz
More info: man rsyncd.conf
Related
I want to copy files using rsync over ssh, but a "Cannot execute command-line and remote command." is raised, meanwhile it works fine with scp.
Command : rsync -ravh folder XXX:folder
My ssh config is configured as follows :
Host XXX
Hostname YY
User user
RequestTTY yes
RemoteCommand bash --init-file ~/.bashrc
I noticed that by removing the RemoteCommand option, rsync does the job.
How could I manage to make rsync work while using my current ssh host config ?
Thanks in advance.
How do I prevent rsync from trying to ask for a password for the remote server login?
Note: I am not asking how to set up public key authenticated SSH. I know how to set up public key authenticated SSH. What I am asking is how to prevent rsync from trying to ask for a password if public key authentication fails, like what scp's -B flag does. I am using rsync in a script here, so if it tries to ask for a password, my script will hang, waiting for input that will never come. I want the rsync command to instead fail, so my script can detect the failure and exit gracefully.
Just pass options to the underlying ssh command used by rsync:
rsync -e 'ssh -oBatchMode=yes [other ssh options]' [rest of rsync command]
From the rsync manual:
-e, --rsh=COMMAND specify the remote shell to use
From the ssh manual:
BatchMode
If set to “yes”, passphrase/password querying will be disabled.
This option is useful in scripts and other batch jobs where no
user is present to supply the password. The argument must be
“yes” or “no”. The default is “no”.
This emulates the bahavior os scp -B.
I'm using flask with apache(mod_wsgi).
When I use ssh module with external command subprocess.call("ssh ......",shell=True)
(My Python Flask code : Not wrong)
ssh = "sshpass -p \""+password+"\" ssh -p 6001 "+username+"#"+servername+" \"mkdir ~/MY_SERVER\""
subprocess.call(ssh, shell=True)
I got this error on Apache error_log : Failed to get a pseudo terminal: Permission denied
How can I fix this?
I've had this problem under RHEL 7. It's due to SELinux blocking apache user to access pty. To solve:
Disable or set SELinux as permissive (check your security needs): edit /etc/selinux/config and reboot.
Allow apache to control its directory for storing SSH keys:
sudo -u apache
chown apache /etc/share/httpd
ssh to desired host, accept key.
I think apache's login shell is "/sbin/nologin".
If you want to allow apache to use shell command, modify /etc/passwd and change the login shell to another shell like "/bin/bash".
However, this method is vulnerable to security. Many python ssh modules are available in internet. Use one of them.
What you are doing seems frightfully insecure. If you cannot use a Python library for your SSH connections, then you should at least plug the hole that is shell=True. There is very little here which is done by the shell anyway; doing it in Python affords you more control, and removes a big number of moving parts.
subprocess.call(['/usr/bin/sshpass', '-p', password,
'/usr/bin/ssh', '-T', '-p', '6001', '{0}#{1}'.format(username, servername),
'mkdir ~/MY_SERVER'])
If you cannot hard-code the paths to sshpass and ssh, you should at least make sure you have a limited, controlled PATH variable in your environment before doing any of this.
The fix for Failed to get a pseudo-terminal is usually to add a -T flag to the ssh command line. I did that above. If your real code actually requires a tty (which mkdir obviously does not), perhaps experiment with -t instead, and/or redirecting standard input and standard output.
I want to sync a directory /var/sites/example.net/ from a remote machine to a directory at the same path on my local machine.
The remote machine only authenticates SSH connections with keys, not passwords.
On my local machine I have an alias set up in ~/.ssh/config so that I can easily run ssh myserver to get in.
I'm trying rsync -a myserver:/var/sites/example.net/ /var/sites/example.net/ but it fails because my local user does not have permission to edit the local directory /var/sites/example.net/.
If I try sudo rsync -a myserver:/var/sites/example.net/ /var/sites/example.net/ (just adding sudo), I can fix the local permission issue, but then I encounter a different issue -- my local root user does not see the proper ssh key or ssh alias.
Is there a way I can accomplish this file sync by modifying this rsync command? I'd like to avoid changing anything else (e.g. no changes to file perms or ssh setup)
Try this:
sudo rsync -e "sudo -u localuser ssh" -a myserver:/var/sites/example.net/ /var/sites/example.net/
This runs rsync as root, but the -e flag causes rsync to run ssh as your local user (using sudo -u localuser), so the ssh command has access to the necessary credentials. Rsync itself is still running as root, so it has the necessary filesystem permissions.
Just improving on top of larsks's response:
sudo rsync -e "sudo -u $USER ssh" ...
So in your case change rsync -a myserver:/var/sites/example.net/ /var/sites/example.net/ to sudo rsync -e "sudo -u $USER ssh" -a myserver:/var/sites/example.net/ /var/sites/example.net/.
With regards to #larsks' answer, If you have your key loaded into the ssh agent, which is my use case, you can instead do:
sudo rsync -e "env SSH_AUTH_SOCK=$SSH_AUTH_SOCK ssh" /source/path /destination/path
Instead of the double sudo.
My use case, if anyone is interested in replicating, is that I'm SSHing to a non-root sudo-er account on remote A, and need to rsync root-owned files between remote A and remote B. Authentication to both remotes is done using keys I have on my real local machine and I use -A to forward the ssh-agent authentication socket to remote A.
Guss's answer works well if you want to use sudo rsync for local file permissions but want to utilise your user's SSH session. However, it falls short when you also want to use your SSH config file.
You can follow Wernight's approach by using sudo to switch the user for the SSH connection and supplying a path to the config file, but this won't work if you have to enter a passphrase. So, you can combine both approaches by making use of the --preserve-env flag:
sudo --preserve-env=SSH_AUTH_SOCK rsync -e "sudo --preserve-env=SSH_AUTH_SOCK -u $USER ssh" hostname:/source/path /destination/path
Note that it's necessary to cascade this flag through both sudo commands so it does look a bit messy!
As requested by Derek above:
when sudo asks for a password then you need to modify the sudoers config with sudo visudo and add a entry with NOPASSWD: in front of the rsync command.
For details you could consult man sudoers.
this will work in every mode, even via cron, at, systemd.service+timer, etc.
test it with: ssh <user>#<your-server> "sudo <your-rsync-command>"
I am trying to connect to a remote host from my local host through the below command.But there was a setting in the remote host that soon after we login it will prompt to enter a badge ID,password and reason for logging in, because it was coded like that in profile file on remote-host How can I overcome those steps and login directly non-interactively, without disturbing the code in profile.
jsmith#local-host$ ssh -t -t generic_userID#remote-host
Enter your badgeID, < exit > to abort:
Enter your password for <badgeID> :
Enter a one line justification for your interactive login to generic_userID
Small amendment: to overcome remote server expect approach is required, but in case local script connects to bunch of remote servers, which configuration may be broken, just use SSH options:
ssh -f -q -o BatchMode=yes -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null USER#TARGETSYSTEM
This will omit ask for password in case there is no ssh_key setup, exit silently and continue with script/other hosts.
Puts ssh to background with -f, which is required when calling ssh command from sh (batch) file to remove local console redirect to remote input (implies -n).
Look into setting up a wrapper script around expect. This should do exactly what you're looking for.
Here are a few examples you can work from.
I have upvoted Marvin Pinto's answer because there is every reason to script this, in case there are other features in the profile that you need, such as Message of the Day motd.
However, there is a quick and dirty alternative if you don't want to make a script and you don't want other features from the profile. Depending on your preferred shell on the remote host, you can insist that the shell bypasses the profile files. For example, if bash is available on the remote host, you can invoke it with:
ssh -t -t generic_userID#remote-host bash --noprofile
I tested the above on the macOS 10.13 version of OpenSSH. Normally the command at the end of the ssh invocation is run non-interactively, but the -t flag allows bash to start an interactive shell.
Details are in the Start-up files section of the Bash Reference Manual.