[PATCH] tools/xdg-desktop-portal-spectrum-host: landlock

[Alyssa Ross <hi@alyssa.is>]

This program doesn't do anything restricted by landlock, so we can
just set up a maximally restrictive ruleset and be done with it.

Signed-off-by: Alyssa Ross <hi@alyssa.is>
---
 .../Cargo.lock                                | 32 +++++++++++++++++++
 .../Cargo.toml                                |  1 +
 .../src/main.rs                               | 19 ++++++++++-
 3 files changed, 51 insertions(+), 1 deletion(-)

diff --git a/tools/xdg-desktop-portal-spectrum-host/Cargo.lock b/tools/xdg-desktop-portal-spectrum-host/Cargo.lock
index d09e36ff..147a6b9a 100644
--- a/tools/xdg-desktop-portal-spectrum-host/Cargo.lock
+++ b/tools/xdg-desktop-portal-spectrum-host/Cargo.lock
@@ -513,6 +513,17 @@ dependencies = [
  "hashbrown",
 ]
 
+[[package]]
+name = "landlock"
+version = "0.4.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "49fefd6652c57d68aaa32544a4c0e642929725bdc1fd929367cdeb673ab81088"
+dependencies = [
+ "enumflags2",
+ "libc",
+ "thiserror",
+]
+
 [[package]]
 name = "libc"
 version = "0.2.178"
@@ -767,6 +778,26 @@ dependencies = [
  "windows-sys",
 ]
 
+[[package]]
+name = "thiserror"
+version = "2.0.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f63587ca0f12b72a0600bcba1d40081f830876000bb46dd2337a3051618f4fc8"
+dependencies = [
+ "thiserror-impl",
+]
+
+[[package]]
+name = "thiserror-impl"
+version = "2.0.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3ff15c8ecd7de3849db632e14d18d2571fa09dfc5ed93479bc4485c7a517c913"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "tinystr"
 version = "0.7.6"
@@ -988,6 +1019,7 @@ dependencies = [
  "async-executor",
  "async-io",
  "futures-lite",
+ "landlock",
  "percent-encoding",
  "rustix",
  "url",
diff --git a/tools/xdg-desktop-portal-spectrum-host/Cargo.toml b/tools/xdg-desktop-portal-spectrum-host/Cargo.toml
index 96459c82..7b177cbf 100644
--- a/tools/xdg-desktop-portal-spectrum-host/Cargo.toml
+++ b/tools/xdg-desktop-portal-spectrum-host/Cargo.toml
@@ -10,6 +10,7 @@ edition = "2024"
 async-executor = { version = "1.12.0", features = ["static"] }
 async-io = "2.3.2"
 futures-lite = "2.3.0"
+landlock = "0.4.4"
 percent-encoding = "2.3.1"
 rustix = "0.38.34"
 url = "2.5.0"
diff --git a/tools/xdg-desktop-portal-spectrum-host/src/main.rs b/tools/xdg-desktop-portal-spectrum-host/src/main.rs
index 3fc49cf3..a8672197 100644
--- a/tools/xdg-desktop-portal-spectrum-host/src/main.rs
+++ b/tools/xdg-desktop-portal-spectrum-host/src/main.rs
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: EUPL-1.2+
-// SPDX-FileCopyrightText: 2024 Alyssa Ross <hi@alyssa.is>
+// SPDX-FileCopyrightText: 2024-2025 Alyssa Ross <hi@alyssa.is>
 
 mod documents;
 mod file_chooser;
@@ -19,6 +19,10 @@ use async_executor::StaticExecutor;
 use async_io::Async;
 use futures_lite::prelude::*;
 use futures_lite::stream::StreamExt;
+use landlock::{
+    ABI, Access, AccessFs, AccessNet, CompatLevel, Compatible, Ruleset, RulesetAttr, RulesetError,
+    Scope,
+};
 use zbus::{AuthMechanism, Connection, MessageStream, connection};
 
 use file_chooser::FileChooser;
@@ -208,6 +212,17 @@ fn listening_vsock_path(connection: &UnixListener) -> Result<PathBuf, String> {
     Ok(OsString::from_vec(listening_addr).into())
 }
 
+fn set_up_landlock() -> Result<(), RulesetError> {
+    Ruleset::default()
+        .handle_access(AccessFs::from_all(ABI::V6))?
+        .handle_access(AccessNet::from_all(ABI::V6))?
+        .scope(Scope::from_all(ABI::V6))?
+        .create()?
+        .set_compatibility(CompatLevel::HardRequirement)
+        .restrict_self()?;
+    Ok(())
+}
+
 fn read_argv() {
     let mut args = args_os();
     args.next();
@@ -219,6 +234,8 @@ fn read_argv() {
 }
 
 fn run() -> Result<(), String> {
+    set_up_landlock().map_err(|e| format!("setting up landlock: {e}"))?;
+
     read_argv();
 
     async_io::block_on(EXECUTOR.run(async {

base-commit: 073642b88d65fd3d5a10e45226cb8ba580ac7bd3
-- 
2.51.0