How do I sudo over sshfs?

This will vary depending on the OS of the server you are connecting to. For centOS 5 you would add to the sshfs mount options:

-o sftp_server="/usr/bin/sudo /usr/libexec/openssh/sftp-server"

For Ubuntu 9.10 (I think, might be 9.04, but it's probably the same for both) or Debian you would add:

-o sftp_server="/usr/bin/sudo /usr/lib/openssh/sftp-server".

To find an the correct path for other systems running openSSH run

sudo grep Subsystem /etc/ssh/sshd_config

and look for the location of the sftp-server binary.

You might need to setup sudo with NOPASS:{path to sftp-server} or prevalidate with ssh user@host sudo -v so that sudo has a updated timestamp for notty. In my case, my two commands were:

ssh login_user@host sudo -v
sshfs login_user@host:remote_path local_path -o sftp_server="/usr/bin/sudo -u as_user /usr/lib/ssh/sftp-server"

You can use bindfs + sshfs to access other user files (even root).

Firstly you mount your 'root' or any other directory under your user with remapped uid.

ssh -t USER@SERVER "mkdir ~/tmproot; sudo bindfs --map=root/USER / ~/tmproot"

and then simply sshfs into the directory.

sshfs USER@SERVER:tmproot TARGET

But for security it's better to not map whole root / but only part that you need. For example: You can use this method to mount any other user directory to your, for example files from /var/www into ~/www and remap root into your user so you will have full access to it.

If you need access to preserve uid or have access to multiple users then i would create a new user for example "rootfs" with uid=0 and /bin/false and do a normal sshfs.

By deduction, I think this is impossible to achieve in a simple command.

This is because sshfs calls ssh without passing any command but, instead, uses SFTP which is a subsystem of SSH.

From the sshfs manpage:

On the remote computer the SFTP subsystem of SSH is used.

Plus, changing the current user (or 'su' or 'sudo') is not part of the SFTP protocol, though this seems like a very often requested feature.

You might try (but I don't think it will work):

sshfs -o ssh_command='ssh sudo /bin/su bravo' charlie@bravo:/home/charlie ~/foo

I don't understand sshfs very well, so you might be able to get something like that to work, but I couldn't say how, and I would be a little surprised.

Another possibility is to put the command 'sudo /bin/su bravo' in ~/.ssh/rc, but that would affect all of your fs mountings (assuming it worked, which I also doubt) as well as your normal use of ssh.

Sorry for being a debbie downer.

Probably, the best way is through file permissions, as @artifex proposes.

As @Weboide says, it is impossible through sshfs.

But I guess you could create a simple script, let's call it sudossh that will take your $PWD, convert it to /home/delta/ and run the command through ssh and sudo on the remote machine.

Something like this:

#!/usr/bin/env bash

ssh -t charlie@bravo "cd `pwd | sed 's/user\/foo/delta/'`; sudo -u delta $*"

After that you can execute sudossh command and remember to use relative paths.

If you use ssh-agent, you just have to enter your sudo password.

You can sed your way into /etc/ssh/sshd_config to find where sftp-server is, and then run it with sudo. The advantage of using this is that it will work on servers running different distros, as long as ssh_config is in the same place.

#!/bin/sh
sshfs -o sftp_server='/usr/bin/env sudo "$(sed -nE "/^[[:blank:]]*[Ss][Uu][Bb][Ss][Yy][Ss][Tt][Ee][Mm][[:blank:]]+sftp[[:blank:]]+/{s///;s/[[:blank:]]*(|#.*)$//;p;q}" /etc/ssh/sshd_config)"' "$@"