File not found in ScpShell by using user.setHomeDirectory()

[araneolus]

Version

2.15.0

Bug description

I have enable the scpShell to my ScpCommandFactory so the scp will works with winscp, too.
Now I have a Problem, if I am working with chroot home Directory.

Lets show the complete debug way to find out the error.
My chroot Home Directory is '/home/guest' with the file 'abc.txt'
And now, I want to download it with winscp.

The Function doScp(... in the class ScpShell.class will resolve the local Path of the File

   protected void doScp(
            String command, String path, boolean optR, boolean optT, boolean optF, boolean optD, boolean optP)
            throws Exception {
        try {
            ChannelSession channel = getServerChannelSession();
            ScpHelper helper = new ScpHelper(
                    channel.getSession(), getInputStream(), getOutputStream(),
                    fileSystem, opener, listener);
            Path localPath = currentDir.resolve(path);  <----------------------
            if (optT) {
                helper.receive(command, localPath, optR, optD, optP, receiveBufferSize);
            } else {
                helper.send(Collections.singletonList(localPath.toString()), optR, optP, sendBufferSize);
            }
...

The function "public void send(Collection paths, boolean recursive, boolean preserve, int bufferSize) throws IOException "
enables hard coded the check of LinkOptions

    public void send(Collection<String> paths, boolean recursive, boolean preserve, int bufferSize) throws IOException {
        boolean debugEnabled = log.isDebugEnabled();
        readAndValidateOperationAck("send", "Paths");

        LinkOption[] options = IoUtils.getLinkOptions(true);   <----------------------

and now by calling the function

   protected void send(Path local, boolean recursive, boolean preserve, int bufferSize, LinkOption... options)
            throws IOException {
        Path localPath = Objects.requireNonNull(local, "No local path").normalize().toAbsolutePath();
        Session session = getSession();
        Path file = opener.resolveOutgoingFilePath(session, localPath, options);

The resolveOutgoingFilePath(... checks, if the File exists.

   default Path resolveOutgoingFilePath(
            Session session, Path localPath, LinkOption... options)
            throws IOException {
        Boolean status = IoUtils.checkFileExists(localPath, options);   <----------------------

   public static Boolean checkFileExists(Path path, LinkOption... options) {
        boolean followLinks = followLinks(options);  

        try {
            if (followLinks) {
                path.getFileSystem().provider().checkAccess(path);   <----------------------

and now the RootedFilesystem.class wíll check the Access of the file. The Call of unroot(path) will extend the localPath from '/home/guest/abc.txt' to '/home/guest/home/guest/abc.txt'

   @Override
    public void checkAccess(Path path, AccessMode... modes) throws IOException {
        Path r = unroot(path);  <----------------------
        FileSystemProvider p = provider(r);
        try {
            p.checkAccess(r, modes);
        } catch (IOException ex) {
            throw translateIoException(ex, path);
        }
    }

Actual behavior

The Directory "/home/guest/" will be extend to '/home/guest/home/guest'

Expected behavior

The Directory “/home/guest/” should remain '/home/guest', or the path should not be replaced by the local path.

Relevant log output

Other information

No response

[araneolus]

I have test it with my own ScpShell Class and it works well

	@Override
	protected void doScp(
            String command, String path, boolean optR, boolean optT, boolean optF, boolean optD, boolean optP)
            throws Exception {
        try {
            ChannelSession channel = getServerChannelSession();
            ScpHelper helper = new ScpHelper(
                    channel.getSession(), getInputStream(), getOutputStream(),
                    fileSystem, opener, listener);
            //Path localPath = currentDir.resolve(path);
            Path localPath = Paths.get(path); <---------------------

[tomaswolf]

This ScpShellis an awkward mixture of local file system operations and virtual file system operations. Here "localPath" should be a virtual file system path. Correct would be IMO fileSystem.getPath("/", path).

[tomaswolf]

Actually I wonder what happens if there are subdirectories under /home/guest and you cd into a subdirectory, then try to send or receive files. Maybe currentDir should already be a virtual filesystem path.

[tomaswolf]

Actually I wonder what happens if there are subdirectories under /home/guest and you cd into a subdirectory, then try to send or receive files.

Could you check that, please?

[araneolus]

You are right.
Both methods:
Path localPath = Paths.get(path); or Path localPath = fileSystem.getPath("/", path); doesn't work, because the function doScp will call with the String "path" without subpath.

[tomaswolf]

I suspected so. So currentDir needs to become a virtual file system path (and we keep currentDir.resolve(path)), not a native path, and homeDir might need a separate setting.

In the current out-of-the-box setup, the homeDir is always the root of the virtual file system. So either we remove homeDir altogether, or if someone wants to have a file system rooted somwhere but have a "home dir" somewhere underneath that, a new way to specify that is needed.