Jumphost support

[MartyMcFlyInTheSky]

Does libssh-rs support jumphosts? I'm trying to SSHMUX connect to a host that needs a jumphost in between. The ssh-config for the host looks like the following:

Host jump-host
  User process
  Hostname jump-host.org.loc.p

Host *.org.loc.p.company.com
  ProxyJump jump-host

Now after wezterm connect SSHMUX:server01 (for which i configured an ssh_domain) I'm getting this error:

09:22:21.160  ERROR  mux::connui >
Failed: Error: Connecting to server01.org.loc.p.company.com:22 (10.120.206.20:22): Connection timed out (os error 110)

09:22:21.161  ERROR  wezterm_gui > Error: Connecting to server.org.loc.p.company.com:22 (10.120.206.20:22): Connection timed out (os error 110); terminating
09:22:21.161  ERROR  mux::connui > while running ConnectionUI loop: recv_timeout: channel is empty and disconnected

[wez]

See:

• ssh via proxycommand / proxyJump wezterm/wezterm#6343

[MartyMcFlyInTheSky]

I see. Is this planned to be fixed at some point?

[midnightveil]

OK, so, after investigating some more (for wezterm/wezterm#7160); I don't think this is an issue with libssh-rs; it is more an issue with libssh itself. Furthermore, for wezterm ssh, it's not related at all, because wezterm does the parsing of the ssh config itself

It seems like libssh has a half-baked implementation of ProxyCommand/ProxyJump in v10, and only kinds of work (see various issues on their issue tracker). Their recommended solution seems to be to enable WITH_EXEC which when the OPENSSH_PROXYJUMP=1 environment variable flag is set will correctly do proxying, which has worked for a while.

With the following change to build.rs (their CMake defaults WITH_EXEC to ON), when I run OPENSSH_PROXYJUMP=1 cargo run --example whoami it does do ProxyJumping correctly (after modifying the whoami example to point at a proxyjump'd host).

diff --git a/libssh-rs-sys/build.rs b/libssh-rs-sys/build.rs
index b9aea88..9e482f7 100644
--- a/libssh-rs-sys/build.rs
+++ b/libssh-rs-sys/build.rs
@@ -71,6 +71,7 @@ fn main() {
     cfg.define("WITH_GEX", Some("1"));
     cfg.define("WITH_SFTP", Some("1"));
     cfg.define("WITH_SERVER", Some("1"));
+    cfg.define("WITH_EXEC", Some("1"));

     if target.contains("windows") {
         cfg.define("HAVE_IO_H", Some("1"));

tldr; don't think this is actually an issue with the rust bindings of libssh-rs themselves, but of wezterm/libssh.