feat(hh): real VM unix users + sudo delegation ⛧

Linux-style user permissions inside the sandbox (the original superuser ask):
- Backends are now persistent (docker run -d + exec; multipass instance) so the
  broker can provision accounts and run the shell as a chosen user.
- sbx::provision(): create a real unix account per coven member at launch; the
  OWNER becomes a passwordless superuser (sudo group + /etc/sudoers.d NOPASSWD
  drop-in on multipass). The shared shell runs as the owner's account.
- /sudo <user> and /unsudo <user> (owner-only): real usermod + sudoers.d in the
  VM — delegate/withdraw superuser. ACL frame carries sudoers; roster shows
  ⛧ owner · ⚡ sudoer · ◆ driver · • member.

Verified live on a real Multipass VM: shell runs as owner@vm with
'sudo -n whoami' == root; '/sudo member' gives member 'NOPASSWD: ALL';
teardown purges the instance. Docker provisions accounts + persistent
container (shell as root; sudo pkg absent so drive-grant is the delegation).

Tests: 7 cargo tests pass; clean build.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

hh/src/app.rs

@@ -65,7 +65,7 @@ pub enum Net {
     SbxResize { rows: u16, cols: u16 },
     SbxData(Vec<u8>),
     SbxInput { from: String, bytes: Vec<u8> },
-    Perm { owner: String, drivers: Vec<String> },
+    Perm { owner: String, drivers: Vec<String>, sudoers: Vec<String> },
     Ft(ft::Ft),
     Sys(String),
     Closed,
@@ -87,6 +87,8 @@ pub struct App {
     pub driving: bool,
     pub owner: Option<String>,
     pub drivers: std::collections::HashSet<String>,
+    /// Members whose VM unix account has sudo (superuser). Always includes owner.
+    pub sudoers: std::collections::HashSet<String>,
     pub pending_offer: Option<ft::Offer>,
     transfers: HashMap<String, Transfer>,
 }
@@ -104,6 +106,7 @@ impl App {
             driving: false,
             owner: None,
             drivers: std::collections::HashSet::new(),
+            sudoers: std::collections::HashSet::new(),
             pending_offer: None,
             transfers: HashMap::new(),
         }
@@ -158,6 +161,7 @@ impl App {
                     self.driving = false;
                     self.owner = None;
                     self.drivers.clear();
+                    self.sudoers.clear();
                     self.sys("⛧ sandbox dismissed");
                 }
             }
@@ -172,8 +176,9 @@ impl App {
                 }
             }
             Net::SbxInput { .. } => {} // broker enforces + writes in the run loop
-            Net::Perm { owner, drivers } => {
+            Net::Perm { owner, drivers, sudoers } => {
                 let new: std::collections::HashSet<String> = drivers.into_iter().collect();
+                let sudo: std::collections::HashSet<String> = sudoers.into_iter().collect();
                 if !owner.is_empty() && self.owner.as_deref() != Some(owner.as_str()) {
                     self.sys(format!("⛧ {owner} is the superuser (sandbox owner)"));
                 }
@@ -183,8 +188,12 @@ impl App {
                     self.driving = false;
                     self.sys("⛧ your drive permission was revoked");
                 }
+                if sudo.contains(&self.me) && !self.sudoers.contains(&self.me) && self.owner.is_some() {
+                    self.sys("⛧ you were granted sudo (superuser) in the VM");
+                }
                 self.owner = Some(owner).filter(|o| !o.is_empty());
                 self.drivers = new;
+                self.sudoers = sudo;
             }
             Net::Ft(_) => {} // handled in the run loop (needs out channel + disk)
             Net::Sys(t) => self.sys(t),
@@ -230,7 +239,10 @@ fn send_frame(out: &UnboundedSender<WsMsg>, room: &fernet::Fernet, value: serde_
 
 fn broadcast_acl(out: &UnboundedSender<WsMsg>, room: &fernet::Fernet, app: &App) {
     let drivers: Vec<&String> = app.drivers.iter().collect();
-    send_frame(out, room, json!({"_perm":"acl","owner": app.owner, "drivers": drivers}));
+    let sudoers: Vec<&String> = app.sudoers.iter().collect();
+    send_frame(out, room, json!({
+        "_perm":"acl","owner": app.owner, "drivers": drivers, "sudoers": sudoers
+    }));
 }
 
 /// Stream a payload to the coven as `_ft` chunks (background, paced).
@@ -421,6 +433,8 @@ pub async fn run(session: Session, theme: Theme) -> Result<()> {
                         app.owner = Some(app.me.clone());
                         app.drivers.clear();
                         app.drivers.insert(app.me.clone());
+                        app.sudoers.clear();
+                        app.sudoers.insert(app.me.clone()); // owner = superuser
                         send_frame(&out_tx, &session.room, json!({
                             "_sbx":"status","state":"ready","backend": backend.label(), "rows": rows, "cols": cols
                         }));
@@ -538,8 +552,10 @@ fn handle_command(
                     let sz = term.size().map(|s| (s.width, s.height)).unwrap_or((80, 24));
                     let (rows, cols) = sbx_dims(sz.0, sz.1);
                     *launching = true;
-                    app.sys(format!("summoning {} sandbox… (multipass boot can take ~30s)", backend.label()));
-                    spawn_launch(backend, image, rows, cols, pty_tx.clone(), broker_tx.clone(), app_tx.clone());
+                    let members: Vec<String> = app.users.iter().map(|u| u.username.clone()).collect();
+                    app.sys(format!("summoning {} sandbox… (provisioning unix users; multipass boot ~30s)", backend.label()));
+                    spawn_launch(backend, image, app.me.clone(), members, rows, cols,
+                        pty_tx.clone(), broker_tx.clone(), app_tx.clone());
                 }
             }
             Some("stop") => {
@@ -556,6 +572,36 @@ fn handle_command(
             }
             _ => app.sys("usage: /sbx launch [local|docker|multipass] [image] | /sbx stop"),
         }
+    } else if let Some(rest) = line.strip_prefix("/unsudo") {
+        let target = rest.trim();
+        if !app.is_owner() {
+            app.sys("only the owner can /unsudo");
+        } else if target.is_empty() {
+            app.sys("usage: /unsudo <user>");
+        } else if let Some((be, name)) = broker_meta.clone() {
+            app.sudoers.remove(target);
+            let (t, n) = (target.to_string(), name);
+            tokio::task::spawn_blocking(move || sbx::set_sudo(be, &n, &t, false));
+            broadcast_acl(out_tx, room, app);
+            app.sys(format!("revoked sudo from {target} in the VM"));
+        } else {
+            app.sys("no sandbox running");
+        }
+    } else if let Some(rest) = line.strip_prefix("/sudo") {
+        let target = rest.trim();
+        if !app.is_owner() {
+            app.sys("only the owner can delegate sudo");
+        } else if target.is_empty() {
+            app.sys("usage: /sudo <user>  (delegate VM superuser) | /unsudo <user>");
+        } else if let Some((be, name)) = broker_meta.clone() {
+            app.sudoers.insert(target.to_string());
+            let (t, n) = (target.to_string(), name);
+            tokio::task::spawn_blocking(move || sbx::set_sudo(be, &n, &t, true));
+            broadcast_acl(out_tx, room, app);
+            app.sys(format!("delegated VM superuser (sudo) to {target}"));
+        } else {
+            app.sys("no sandbox running");
+        }
     } else if let Some(rest) = line.strip_prefix("/grant") {
         let target = rest.trim();
         if !app.is_owner() {
@@ -585,9 +631,12 @@ fn handle_command(
     }
 }
 
+#[allow(clippy::too_many_arguments)]
 fn spawn_launch(
     backend: sbx::Backend,
     image: String,
+    owner: String,
+    members: Vec<String>,
     rows: u16,
     cols: u16,
     pty_tx: UnboundedSender<Vec<u8>>,
@@ -605,8 +654,15 @@ fn spawn_launch(
             let _ = broker_tx.send(BrokerMsg::Failed);
             return;
         }
+        // Provision real unix accounts (owner = sudoer) → the shell's run-user.
+        let run_user = {
+            let (n, o, ms) = (name.clone(), owner.clone(), members.clone());
+            tokio::task::spawn_blocking(move || sbx::provision(backend, &n, &o, &ms))
+                .await
+                .unwrap_or_default()
+        };
         let (std_tx, std_rx) = std::sync::mpsc::channel::<Vec<u8>>();
-        match sbx::Sandbox::launch(backend, &name, &image, rows, cols, std_tx) {
+        match sbx::Sandbox::launch(backend, &name, &run_user, rows, cols, std_tx) {
             Ok(sb) => {
                 std::thread::spawn(move || {
                     while let Ok(b) = std_rx.recv() {

hh/src/net.rs

@@ -192,15 +192,18 @@ fn parse_perm(text: &str) -> Option<Net> {
     if v["_perm"].as_str()? != "acl" {
         return None;
     }
-    let drivers = v["drivers"]
+    let list = |key: &str| {
+        v[key]
             .as_array()
             .into_iter()
             .flatten()
             .filter_map(|d| d.as_str().map(str::to_string))
-        .collect();
+            .collect::<Vec<_>>()
+    };
     Some(Net::Perm {
         owner: v["owner"].as_str().unwrap_or("").to_string(),
-        drivers,
+        drivers: list("drivers"),
+        sudoers: list("sudoers"),
     })
 }
 

hh/src/sbx.rs

@@ -51,9 +51,9 @@ impl Backend {
 /// thread (Multipass boots a real VM, ~20-30s). Idempotent: reuses an instance
 /// that already exists.
 pub fn prepare(backend: Backend, name: &str, image: &str) -> Result<()> {
-    if backend != Backend::Multipass {
-        return Ok(());
-    }
+    match backend {
+        Backend::Local => Ok(()),
+        Backend::Multipass => {
             let exists = Command::new("multipass")
                 .args(["info", name])
                 .output()
@@ -61,9 +61,7 @@ pub fn prepare(backend: Backend, name: &str, image: &str) -> Result<()> {
                 .unwrap_or(false);
             if !exists {
                 let st = Command::new("multipass")
-            .args([
-                "launch", "--name", name, "--cpus", "1", "--memory", "1G", "--disk", "5G", image,
-            ])
+                    .args(["launch", "--name", name, "--cpus", "1", "--memory", "1G", "--disk", "5G", image])
                     .status()
                     .context("multipass launch (is multipass installed?)")?;
                 anyhow::ensure!(st.success(), "multipass launch failed");
@@ -71,20 +69,37 @@ pub fn prepare(backend: Backend, name: &str, image: &str) -> Result<()> {
                 let _ = Command::new("multipass").args(["start", name]).status();
             }
             Ok(())
-}
-
-/// Destroy ephemeral resources after stop. Multipass instance is purged;
-/// Docker uses `--rm` so the container is already gone; Local is a no-op.
-pub fn teardown(backend: Backend, name: &str) {
-    if backend == Backend::Multipass {
-        let _ = Command::new("multipass")
-            .args(["delete", name, "--purge"])
-            .status();
+        }
+        Backend::Docker => {
+            // Persistent container so we can exec in to provision users + shells.
+            let _ = Command::new("docker").args(["rm", "-f", name]).status();
+            let st = Command::new("docker")
+                .args(["run", "-d", "--name", name, "--hostname", name, "-w", "/root", image, "sleep", "infinity"])
+                .status()
+                .context("docker run (is docker installed?)")?;
+            anyhow::ensure!(st.success(), "docker run failed");
+            Ok(())
+        }
     }
 }
 
-/// Build the shell command that launches the sandbox for a backend.
-fn command_for(backend: Backend, name: &str, image: &str) -> CommandBuilder {
+/// Destroy ephemeral resources after stop. Multipass instance is purged;
+/// the Docker container is removed; Local is a no-op.
+pub fn teardown(backend: Backend, name: &str) {
+    match backend {
+        Backend::Multipass => {
+            let _ = Command::new("multipass").args(["delete", name, "--purge"]).status();
+        }
+        Backend::Docker => {
+            let _ = Command::new("docker").args(["rm", "-f", name]).status();
+        }
+        Backend::Local => {}
+    }
+}
+
+/// Build the shell command for a backend, running as unix user `run_user`
+/// (empty = backend default). The container/VM is already up (see `prepare`).
+fn command_for(backend: Backend, name: &str, run_user: &str) -> CommandBuilder {
     match backend {
         Backend::Local => {
             let mut c = CommandBuilder::new("bash");
@@ -92,21 +107,106 @@ fn command_for(backend: Backend, name: &str, image: &str) -> CommandBuilder {
             c
         }
         Backend::Docker => {
+            let user = if run_user.is_empty() { "root" } else { run_user };
             let mut c = CommandBuilder::new("docker");
-            c.args([
-                "run", "--rm", "-i", "--hostname", name, "-w", "/root", image, "bash", "-i",
-            ]);
+            c.args(["exec", "-it", "-u", user, name, "bash", "-il"]);
             c
         }
         Backend::Multipass => {
-            // Assumes the instance `name` was launched separately (P3b lifecycle).
             let mut c = CommandBuilder::new("multipass");
+            if run_user.is_empty() {
                 c.args(["exec", name, "--", "bash", "-il"]);
+            } else {
+                // Login shell as the provisioned owner account (a real sudoer).
+                c.args(["exec", name, "--", "sudo", "-u", run_user, "-i"]);
+            }
             c
         }
     }
 }
 
+/// Sanitize a coven display name into a safe unix username.
+pub fn unix_name(name: &str) -> String {
+    let s: String = name
+        .to_lowercase()
+        .chars()
+        .filter(|c| c.is_ascii_alphanumeric() || *c == '_' || *c == '-')
+        .take(31)
+        .collect();
+    s.trim_start_matches(['-', '_']).to_string()
+}
+
+fn mp(name: &str, args: &[&str]) {
+    let mut a = vec!["exec", name, "--"];
+    a.extend_from_slice(args);
+    let _ = Command::new("multipass").args(a).status();
+}
+fn dk(name: &str, args: &[&str]) {
+    let mut a = vec!["exec", name];
+    a.extend_from_slice(args);
+    let _ = Command::new("docker").args(a).status();
+}
+
+/// Grant a Multipass user real *passwordless* sudo (group + sudoers.d drop-in)
+/// so they're a usable superuser non-interactively. `u` is already unix-safe.
+fn mp_grant_sudo(name: &str, u: &str) {
+    let script = format!(
+        "usermod -aG sudo {u}; printf '{u} ALL=(ALL) NOPASSWD:ALL\\n' > /etc/sudoers.d/90-{u}; chmod 440 /etc/sudoers.d/90-{u}"
+    );
+    mp(name, &["sudo", "bash", "-c", &script]);
+}
+fn mp_revoke_sudo(name: &str, u: &str) {
+    let script = format!("gpasswd -d {u} sudo 2>/dev/null; rm -f /etc/sudoers.d/90-{u}");
+    mp(name, &["sudo", "bash", "-c", &script]);
+}
+
+/// Provision a real unix account per coven member inside the VM/container and
+/// make the owner a superuser (sudoer). Returns the unix user the shared shell
+/// should run as. Blocking — call off the UI thread.
+pub fn provision(backend: Backend, name: &str, owner: &str, members: &[String]) -> String {
+    let run = unix_name(owner);
+    match backend {
+        Backend::Multipass => {
+            for m in members {
+                let u = unix_name(m);
+                if !u.is_empty() {
+                    mp(name, &["sudo", "useradd", "-m", "-s", "/bin/bash", &u]);
+                }
+            }
+            if !run.is_empty() {
+                mp_grant_sudo(name, &run); // owner = passwordless superuser
+            }
+            run
+        }
+        Backend::Docker => {
+            for m in members {
+                let u = unix_name(m);
+                if !u.is_empty() {
+                    dk(name, &["useradd", "-m", "-s", "/bin/bash", &u]);
+                }
+            }
+            // Base images usually lack the sudo package; the shared shell runs as
+            // root (superuser) and drive-grant is the delegation mechanism.
+            "root".to_string()
+        }
+        Backend::Local => String::new(),
+    }
+}
+
+/// Grant/revoke real sudo for a member's unix account (Multipass; sudo is
+/// preinstalled). No-op for Docker (no sudo pkg) / Local.
+pub fn set_sudo(backend: Backend, name: &str, user: &str, enable: bool) {
+    let u = unix_name(user);
+    if u.is_empty() || backend != Backend::Multipass {
+        return;
+    }
+    if enable {
+        mp_grant_sudo(name, &u);
+    } else {
+        mp_revoke_sudo(name, &u);
+    }
+}
+
 pub struct Sandbox {
     // Held for the PTY's lifetime (dropping it closes the terminal) + resize.
     #[allow(dead_code)]
@@ -123,7 +223,7 @@ impl Sandbox {
     pub fn launch(
         backend: Backend,
         name: &str,
-        image: &str,
+        run_user: &str,
         rows: u16,
         cols: u16,
         out: mpsc::Sender<Vec<u8>>,
@@ -138,7 +238,7 @@ impl Sandbox {
             })
             .context("openpty")?;
 
-        let cmd = command_for(backend, name, image);
+        let cmd = command_for(backend, name, run_user);
         let child = pair
             .slave
             .spawn_command(cmd)
@@ -203,7 +303,7 @@ mod tests {
     #[test]
     fn local_shell_pty_roundtrip() {
         let (tx, rx) = mpsc::channel();
-        let mut sb = Sandbox::launch(Backend::Local, "test", "ubuntu:24.04", 24, 80, tx)
+        let mut sb = Sandbox::launch(Backend::Local, "test", "", 24, 80, tx)
             .expect("launch local shell");
         sb.write_input(b"echo HELLO_PTY_42\n").unwrap();
 
@@ -242,7 +342,7 @@ mod relay_tests {
         use base64::Engine;
 
         let (tx, rx) = mpsc::channel();
-        let mut sb = Sandbox::launch(Backend::Local, "test", "ubuntu:24.04", 24, 80, tx)
+        let mut sb = Sandbox::launch(Backend::Local, "test", "", 24, 80, tx)
             .expect("launch");
         sb.write_input(b"echo RELAY_MARKER_7\n").unwrap();
 

hh/src/ui.rs

@@ -116,10 +116,12 @@ fn draw_roster(f: &mut Frame, area: ratatui::layout::Rect, app: &App, theme: &Th
         .iter()
         .map(|u| {
             let me = u.username == app.me;
-            // ⛧ owner/superuser · ◆ may drive · • member
+            // ⛧ owner · ⚡ sudoer (VM superuser) · ◆ may drive · • member
             let owner = app.owner.as_deref() == Some(u.username.as_str());
             let mark = if owner {
                 "⛧"
+            } else if app.sudoers.contains(&u.username) {
+                "⚡"
             } else if app.drivers.contains(&u.username) {
                 "◆"
             } else {