Fix LXC password reset (501 on nonexistent lxc/exec endpoint)

app.py

@@ -6375,15 +6375,18 @@ def _ssh_target_for_node(node: str) -> tuple[str | None, bool]:
     return meta.get("host"), meta.get("verify_ssl", True)
 
 
-def _ssh_connect_root(node: str, timeout: int = 20):
+def _ssh_connect_root(node: str, timeout: int = 20, host: str | None = None):
     """Open a paramiko SSHClient to `node` as root using ProxUI's key.
 
-    Returns the connected client, or raises. Caller must close it.
+    `host` overrides the address to connect to — needed for node-specific
+    commands (e.g. `pct exec`) since connection_metadata maps discovered nodes
+    to the configured API endpoint, not their own address. Caller must close it.
     """
     paramiko = _get_paramiko()
     if not paramiko:
         raise SnippetWriteError("paramiko is not installed (pip install paramiko).")
-    host, _ = _ssh_target_for_node(node)
+    if host is None:
+        host, _ = _ssh_target_for_node(node)
     if not host:
         raise SnippetWriteError(f"No connection host known for node '{node}'.")
     if not os.path.exists(_SSH_KEY_PATH):
@@ -6468,11 +6471,29 @@ def _sftp_read_file(node: str, remote_path: str) -> str:
         client.close()
 
 
-def _ssh_run_root(node: str, command: str, timeout: int = 30) -> tuple[int, str, str]:
-    """Run a command on `node` as root via SSH. Returns (exit_code, stdout, stderr)."""
-    client = _ssh_connect_root(node, timeout=timeout)
+def _ssh_run_root(
+    node: str,
+    command: str,
+    timeout: int = 30,
+    stdin_data: str | None = None,
+    host: str | None = None,
+) -> tuple[int, str, str]:
+    """Run a command on `node` as root via SSH. Returns (exit_code, stdout, stderr).
+
+    If stdin_data is given it is written to the command's stdin (e.g. to feed
+    `chpasswd`) so secrets never appear on the command line. `host` overrides the
+    address (needed for node-specific commands — see _ssh_connect_root).
+    """
+    client = _ssh_connect_root(node, timeout=timeout, host=host)
     try:
-        _stdin, stdout, stderr = client.exec_command(command, timeout=timeout)
+        stdin, stdout, stderr = client.exec_command(command, timeout=timeout)
+        if stdin_data is not None:
+            stdin.write(stdin_data)
+            stdin.flush()
+            try:
+                stdin.channel.shutdown_write()
+            except Exception:
+                pass
         rc = stdout.channel.recv_exit_status()
         out = stdout.read().decode("utf-8", errors="replace")
         err = stderr.read().decode("utf-8", errors="replace")
@@ -6481,9 +6502,10 @@ def _ssh_run_root(node: str, command: str, timeout: int = 30) -> tuple[int, str,
         client.close()
 
 
-def _ssh_port_open(node: str, timeout: float = 4.0) -> bool:
-    """Quick TCP check for SSH (port 22) reachability."""
-    host, _ = _ssh_target_for_node(node)
+def _ssh_port_open(node: str, timeout: float = 4.0, host: str | None = None) -> bool:
+    """Quick TCP check for SSH (port 22) reachability. `host` overrides the address."""
+    if host is None:
+        host, _ = _ssh_target_for_node(node)
     if not host:
         return False
     try:
@@ -7636,6 +7658,97 @@ def api_vm_agent(node, vmid):
         return _proxmox_error_response(e)
 
 
+def _node_address(node: str) -> str | None:
+    """Real management address of a specific cluster node, for node-local commands.
+
+    connection_metadata maps discovered nodes to the configured API endpoint, so
+    it can't reach a *specific* node (e.g. to run `pct exec`, which must run on
+    the node that owns the container). Look the node's IP up via cluster status.
+    """
+    proxmox = get_proxmox_connection(node, auto_renew=True)
+    if not proxmox:
+        return None
+    try:
+        for entry in proxmox.cluster.status.get():
+            if (
+                entry.get("type") == "node"
+                and entry.get("name") == node
+                and entry.get("ip")
+            ):
+                return entry["ip"]
+    except Exception:
+        return None
+    return None
+
+
+def _reset_lxc_root_password(node: str, vmid: str, password: str) -> str:
+    """Set an LXC container's root password by running chpasswd via `pct exec`.
+
+    Proxmox has no REST API to exec inside a container (unlike QEMU's guest
+    agent), so we run `pct exec <vmid> -- chpasswd` on the node over the same
+    channels the snippet writer uses, feeding `root:<password>` on stdin so the
+    secret never lands in the process list or shell history:
+      1. SSH as root  — ProxUI's key installed and port 22 open (stdin pipe)
+      2. node Shell    — root@pam console, via a short-lived temp file
+    Returns the channel used, or raises SnippetWriteError with what to fix.
+    """
+    payload = f"root:{password}\n"
+    qvmid = shlex.quote(str(vmid))
+    errors = []
+
+    # `pct exec` must run ON the node that owns the container. connection_metadata
+    # points discovered nodes at the configured API endpoint, so resolve the
+    # owning node's real address for the SSH tier. (The termproxy tier already
+    # reaches the right node — /nodes/<node>/termproxy is proxied there.)
+    host = _node_address(node)
+
+    # Tier 1: SSH as root with ProxUI's key — password stays on the stdin pipe.
+    if os.path.exists(_SSH_KEY_PATH) and host and _ssh_port_open(node, host=host):
+        try:
+            rc, out, err = _ssh_run_root(
+                node,
+                f"pct exec {qvmid} -- chpasswd",
+                stdin_data=payload,
+                host=host,
+            )
+            if rc == 0:
+                return "ssh"
+            errors.append(f"SSH: {(err or out)[-200:].strip()}")
+        except Exception as e:
+            errors.append(f"SSH: {e}")
+
+    # Tier 2: node Shell (root@pam) — write the payload to a temp file, feed it to
+    # chpasswd, then remove it.
+    if _is_root_pam(node):
+        try:
+            sess = _termproxy_open(node)
+            try:
+                tmp = f"/tmp/proxui-pw-{uuid.uuid4().hex}"
+                qtmp = shlex.quote(tmp)
+                sess.write_file(tmp, payload)
+                rc, out = sess.run(
+                    f"pct exec {qvmid} -- chpasswd < {qtmp}; "
+                    f"rc=$?; rm -f {qtmp}; exit $rc"
+                )
+                if rc == 0:
+                    return "termproxy"
+                errors.append(f"node Shell: {out[-200:].strip()}")
+            finally:
+                sess.close()
+        except Exception as e:
+            errors.append(f"node Shell: {e}")
+
+    detail = (
+        "; ".join(errors)
+        if errors
+        else (
+            "no usable channel — set up ProxUI SSH access to the node "
+            "(Cloud-Init → Custom Snippet → Set up access), or connect as root@pam."
+        )
+    )
+    raise SnippetWriteError(f"Could not reset the container password: {detail}")
+
+
 @app.route("/api/vm/<node>/<vmid>/reset-password", methods=["POST"])
 def api_vm_reset_password(node, vmid):
     """Reset root password: LXC via pct exec, QEMU via guest agent with cipassword fallback."""
@@ -7658,12 +7771,15 @@ def api_vm_reset_password(node, vmid):
                     jsonify({"error": "Container must be running to reset password"}),
                     400,
                 )
-            proxmox.nodes(node).lxc(vmid).exec.post(
-                command=["chpasswd"],
-                stdin=f"root:{password}\n",
-            )
+            try:
+                channel = _reset_lxc_root_password(node, vmid, password)
+            except SnippetWriteError as e:
+                return jsonify({"error": str(e)}), 400
             return jsonify(
-                {"success": True, "message": "Root password updated successfully"}
+                {
+                    "success": True,
+                    "message": f"Root password updated successfully (via {channel}).",
+                }
             )
         else:
             # Try guest agent first (immediate effect), fall back to cipassword (next reboot)