Failed to fetch private key every damn time

[Kantotero]

Device Type

Windows

Dev Manager Version

1.99.16

Model

55QNED70ASA

webOS Version

webOS25 / 10.2.0-2101

Rooted

No (with Dev Mode)

Bug Description

I can't connect my windows device laptop with Developer mode using Dev Manager desktop. I already tried all known possible fixes such as turning off and on the Dev Mode, clearing cache data, revoking all agreements and aggreeing again. And even uninstalling and reinstalling the developers mode app.

Reproduction Steps

Try to connect my windows laptop to LGTV using Dev Manager desktop, input correct same IP address and passphrase but keeps showing "failed to fetch private key"

Expected Behavior

Should be able to connect. I wanna install Homebrew channel

[mariotaku]

Is accessing http://ip-of-your-tv:9991/webos_rsa giving you any output?

[bzobl]

I experience the same problem and I have an idea what could be the problem.

For me the problem appeared with v1.99.11 and I think the fix for #319 is causing it.

Commit 9d7dce4 replaced the reqwest::get() with a std::net::TcpStream. This stream is used to get a key from the TV using its /webos_rsa endpoint. The response is read from the stream through stream.read(&mut buffer)?, which does not consider that the response might be split over multiple TCP packets.

In my case the request returns 1766 bytes

wget -o /dev/null -O - http://192.168.1.144:9991/webos_rsa | wc -c 
1766

On the network I can see that the first fragment is a TCP packet with 1448 byte, the remainder is received in a second packet a few tenth of a millisecond later. From my experience the call to read() will return data once available, so I guess it will only read 1448 byte of the key and returns it as allegedly entire SSH key.

I think a quick fix would be to iteratively read from the TCP stream. Something like this

    async fn key_server_fetch(host: &str) -> Result<String, Error> {
        let address = format!("{host}:9991");
        tauri::async_runtime::spawn_blocking(move || {
            let address = address.to_socket_addrs()?.next().ok_or(Error::NotFound)?;
            let mut stream = TcpStream::connect_timeout(&address, Duration::from_secs(5))?;
            stream.write(b"GET /webos_rsa HTTP/1.0\r\n")?;
            stream.write(b"Connection: close\r\n")?;
            stream.write(b"\r\n")?;

            let mut offset = 0;
            let mut buffer = [0u8; 65536];
            loop {
              match stream.read(&mut buffer[offset..])? {
                0 => break,
                n_read => offset += n_read,
              }
            }
            let mut headers = [httparse::EMPTY_HEADER; 64];
            let mut response = Response::new(&mut headers);
            let Status::Complete(size_to_skip) = response
                .parse(&buffer[..buffer_size])
                .map_err(|e| IoError::new(std::io::ErrorKind::InvalidData, e))?
            else {
                return Err(Error::NotFound);
            };
            if response.code.unwrap() != 200 {
                return Err(Error::NotFound);
            }
            Ok(String::from_utf8_lossy(&buffer[size_to_skip..buffer_size]).to_string())
        })
        .await
        .unwrap()
    }

Unfortunately, I currently have no setup to build webos-dev-manager, hence I can't submit a pull request. But I hope this helps anyways.

[Kantotero]

Is accessing http://ip-of-your-tv:9991/webos_rsa giving you any output?

@mariotaku no it gives an error, can't reach the page & took too long to respond

I experience the same problem and I have an idea what could be the problem.

For me the problem appeared with v1.99.11 and I think the fix for #319 is causing it.

Commit 9d7dce4 replaced the reqwest::get() with a std::net::TcpStream. This stream is used to get a key from the TV using its /webos_rsa endpoint. The response is read from the stream through stream.read(&mut buffer)?, which does not consider that the response might be split over multiple TCP packets.

In my case the request returns 1766 bytes

wget -o /dev/null -O - http://192.168.1.144:9991/webos_rsa | wc -c 
1766

On the network I can see that the first fragment is a TCP packet with 1448 byte, the remainder is received in a second packet a few tenth of a millisecond later. From my experience the call to read() will return data once available, so I guess it will only read 1448 byte of the key and returns it as allegedly entire SSH key.

I think a quick fix would be to iteratively read from the TCP stream. Something like this

    async fn key_server_fetch(host: &str) -> Result<String, Error> {
        let address = format!("{host}:9991");
        tauri::async_runtime::spawn_blocking(move || {
            let address = address.to_socket_addrs()?.next().ok_or(Error::NotFound)?;
            let mut stream = TcpStream::connect_timeout(&address, Duration::from_secs(5))?;
            stream.write(b"GET /webos_rsa HTTP/1.0\r\n")?;
            stream.write(b"Connection: close\r\n")?;
            stream.write(b"\r\n")?;

            let mut offset = 0;
            let mut buffer = [0u8; 65536];
            loop {
              match stream.read(&mut buffer[offset..])? {
                0 => break,
                n_read => offset += n_read,
              }
            }
            let mut headers = [httparse::EMPTY_HEADER; 64];
            let mut response = Response::new(&mut headers);
            let Status::Complete(size_to_skip) = response
                .parse(&buffer[..buffer_size])
                .map_err(|e| IoError::new(std::io::ErrorKind::InvalidData, e))?
            else {
                return Err(Error::NotFound);
            };
            if response.code.unwrap() != 200 {
                return Err(Error::NotFound);
            }
            Ok(String::from_utf8_lossy(&buffer[size_to_skip..buffer_size]).to_string())
        })
        .await
        .unwrap()
    }

Unfortunately, I currently have no setup to build webos-dev-manager, hence I can't submit a pull request. But I hope this helps anyways.

This is quite sophisticated and too complex for me as I am not tech-savvy... but thanks hopefully this will reach the devs

[codeater7]

I experience the same problem and I have an idea what could be the problem.

For me the problem appeared with v1.99.11 and I think the fix for #319 is causing it.

Commit 9d7dce4 replaced the reqwest::get() with a std::net::TcpStream. This stream is used to get a key from the TV using its /webos_rsa endpoint. The response is read from the stream through stream.read(&mut buffer)?, which does not consider that the response might be split over multiple TCP packets.

In my case the request returns 1766 bytes

wget -o /dev/null -O - http://192.168.1.144:9991/webos_rsa | wc -c 
1766

On the network I can see that the first fragment is a TCP packet with 1448 byte, the remainder is received in a second packet a few tenth of a millisecond later. From my experience the call to read() will return data once available, so I guess it will only read 1448 byte of the key and returns it as allegedly entire SSH key.

I think a quick fix would be to iteratively read from the TCP stream. Something like this

    async fn key_server_fetch(host: &str) -> Result<String, Error> {
        let address = format!("{host}:9991");
        tauri::async_runtime::spawn_blocking(move || {
            let address = address.to_socket_addrs()?.next().ok_or(Error::NotFound)?;
            let mut stream = TcpStream::connect_timeout(&address, Duration::from_secs(5))?;
            stream.write(b"GET /webos_rsa HTTP/1.0\r\n")?;
            stream.write(b"Connection: close\r\n")?;
            stream.write(b"\r\n")?;

            let mut offset = 0;
            let mut buffer = [0u8; 65536];
            loop {
              match stream.read(&mut buffer[offset..])? {
                0 => break,
                n_read => offset += n_read,
              }
            }
            let mut headers = [httparse::EMPTY_HEADER; 64];
            let mut response = Response::new(&mut headers);
            let Status::Complete(size_to_skip) = response
                .parse(&buffer[..buffer_size])
                .map_err(|e| IoError::new(std::io::ErrorKind::InvalidData, e))?
            else {
                return Err(Error::NotFound);
            };
            if response.code.unwrap() != 200 {
                return Err(Error::NotFound);
            }
            Ok(String::from_utf8_lossy(&buffer[size_to_skip..buffer_size]).to_string())
        })
        .await
        .unwrap()
    }

Unfortunately, I currently have no setup to build webos-dev-manager, hence I can't submit a pull request. But I hope this helps anyways.

Probably this is the fix that is required.
when trying to access http://IP:9991/webos_rsa, I am able to download the private key but when using Dev manager, it fails repeatedly.

[codeater7]

Most likely for the above reason "Use Developer Mode" wont work. However you can select "setup manually".
steps:

1. Ensure to visit http://:9991/webos_rsa and download the private key.
2. select "setup manually" options from the WebOS dev manager.
   username: prisoner ( default)
   Device Port: 9922 (default)

Authentication => Private Key
and select the file that you dowloaded. It prompts for the "SSH Private Key Passphrase". This passphrase is the one that is shown in your Developer mode in your TV.