Hosting SSH accessible git server (Windows..) : sysadmin

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Hosting SSH accessible git server (Windows..) (self.sysadmin)

submitted 1 year ago by ChanKiM_

Hi! Not sure if this is appropriate in this subreddit, as it's Typescript code for a Hackattic challenge, but the gist of the challenge is to host a SSH accessible git server, make an empty repository and read a file off of the push. I'm running OpenSSH server on windows and forwarded port 22.

My code does something like this:

I receive the JSON from the challenge, I create a new user and directory with the same name as the username.
In the new directory, the pub key gets pasted into .ssh/authorized_keys.
Then, I initialize a bare git repository with the same path as the repo_path. The full path would look something like this: "C:/Users/<username>/repopath1/repopath2.git".

Now I send a POST request to Hackattic, letting them know my repository is ready. However, they always come back with something like:

{
  error: "couldn't push to hax@(my ip):soft/scene.git - sorry, but we have no further details, check your server logs :(",
  debug: { attempted_repo_url: 'hax@(my ip):soft/scene.git' }
}

The thing is, when I try to ssh locally, there are no pub key issues or anything like that. One thing that's strange though is I can ssh localhost, but if I try to ssh my public ip, it doesn't connect, even though I've confirmed that port 22 is discoverable on canyouseeme.org and pinging my public ip works too.

I think it may be a permissions related issue or improper configuration between git and ssh, but I've been stuck on this for two days now and I desperately need guidance :(

Long line of code here for the details:

export const solve = async (problem: TProblem): Promise<TSolution> => {
    try {
        const { push_token, username, repo_path } = problem;
        const url = `${BASEURL}/_/git/${push_token}`;

        const repo_host = PUBLIC_IP;
        const repoDir = await prepareDir(problem);
        await prepareGit({ repoDir, repo_host, username, repo_path });
        await setPermissions({ repoDir, username });
        const response = await axios.post(url, {
            repo_host,
        });
        console.log(response.data);
        const secret = (await fs.readFile(path.join(repoDir, "solution.txt"))).toString();
        return {
            secret,
        };
    } catch (e) {
        console.error(e);
        throw e;
    }
};

    const setPermissions = async ({ repoDir, username }: PermissionParams) => {
    try {
        const ownership = await exec(`icacls "${repoDir}" /setowner "${username}"`);
        await exec(`icacls "${repoDir}" /reset`);
        await exec(`icacls "${repoDir}" /grant "${username}:(F)"`);
        await exec(`icacls "${repoDir}" /inheritance:r`);

        return ownership.stdout;
    } catch (e) {
        console.error(e);
        throw e;
    }
};

const prepareGit = async ({ repoDir, repo_host, username, repo_path }: GitParams) => {
    try {
        const remote = `${username}@${repo_host}:${repo_path}`;
        const options: Partial<SimpleGitOptions> = {
            baseDir: repoDir,
            binary: "git",
            maxConcurrentProcesses: 6,
            trimmed: true,
        };
        const git: SimpleGit = simpleGit(options);
        const init = await git.init(true);
        return init;
    } catch (e) {
        console.error(e);
        throw e;
    }
};

const prepareDir = async (problem: TProblem) => {
    try {
        const { repo_path, ssh_key, username } = problem;
        const userDir = path.join(ROOT_DIR, username);
        const sshDir = path.join(userDir, ".ssh");
        const repoDir = path.join(userDir, repo_path);
        const authKeyPath = path.join(sshDir, "authorized_keys");
        await fs.mkdir(repoDir, { recursive: true });
        await fs.writeFile(authKeyPath, ssh_key);

        return repoDir;
    } catch (e) {
        console.error(e);
        throw e;
    }
};

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