From 57176d45cacb98f1968daa8f8b2efd2735da2731 Mon Sep 17 00:00:00 2001
From: murilo ijanc
Date: Wed, 25 Mar 2026 13:58:11 -0300
Subject: Add pledge(2) and unveil(2) sandboxing for tp and tpd

tpd: unveil data dir (rwc), resolv.conf (r) when DNS needed,
then pledge stdio rpath wpath cpath fattr inet unix dns.

tp: unveil socket path (rw), then pledge stdio unix rpath.
---
 src/sandbox.rs | 77 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 77 insertions(+)
 create mode 100644 src/sandbox.rs

(limited to 'src/sandbox.rs')

diff --git a/src/sandbox.rs b/src/sandbox.rs
new file mode 100644
index 0000000..13f6a87
--- /dev/null
+++ b/src/sandbox.rs
@@ -0,0 +1,77 @@
+//! OpenBSD pledge(2) and unveil(2) wrappers.
+
+use std::ffi::{CString, c_char};
+use std::path::Path;
+
+unsafe extern "C" {
+    fn pledge(promises: *const c_char, execpromises: *const c_char) -> i32;
+    fn unveil(path: *const c_char, permissions: *const c_char) -> i32;
+}
+
+/// Valid pledge promises on OpenBSD.
+const VALID_PROMISES: &[&str] = &[
+    "audio", "bpf", "chown", "cpath", "disklabel", "dns", "dpath",
+    "error", "exec", "fattr", "flock", "getpw", "id", "inet", "mcast",
+    "pf", "proc", "ps", "recvfd", "route", "rpath", "sendfd", "settime",
+    "stdio", "tape", "tmppath", "tty", "unix", "unveil", "video",
+    "vminfo", "vmm", "wpath", "wroute",
+];
+
+/// Valid unveil permission characters.
+const VALID_PERMS: &[u8] = b"rwcx";
+
+/// Restrict the process to the given pledge promises.
+pub fn do_pledge(promises: &str) {
+    for word in promises.split_whitespace() {
+        if !VALID_PROMISES.contains(&word) {
+            log::error!("pledge: unknown promise: {word}");
+            std::process::exit(1);
+        }
+    }
+    let c = CString::new(promises).unwrap_or_else(|_| {
+        log::error!("pledge: promises contain NUL byte");
+        std::process::exit(1);
+    });
+    let ret = unsafe { pledge(c.as_ptr(), std::ptr::null()) };
+    if ret != 0 {
+        let err = std::io::Error::last_os_error();
+        log::error!("pledge failed: {err}");
+        std::process::exit(1);
+    }
+    log::debug!("pledge applied");
+}
+
+/// Add a path to the unveil whitelist with the given permissions.
+/// Permissions: "r" read, "w" write, "c" create, "x" execute.
+pub fn do_unveil(path: &Path, perms: &str) {
+    if perms.is_empty() || !perms.as_bytes().iter().all(|b| VALID_PERMS.contains(b)) {
+        log::error!("unveil: invalid permissions");
+        std::process::exit(1);
+    }
+    let p = CString::new(path.as_os_str().as_encoded_bytes()).unwrap_or_else(|_| {
+        log::error!("unveil: path contains NUL byte");
+        std::process::exit(1);
+    });
+    let f = CString::new(perms).unwrap_or_else(|_| {
+        log::error!("unveil: permissions contain NUL byte");
+        std::process::exit(1);
+    });
+    let ret = unsafe { unveil(p.as_ptr(), f.as_ptr()) };
+    if ret != 0 {
+        let err = std::io::Error::last_os_error();
+        log::error!("unveil failed: {err}");
+        std::process::exit(1);
+    }
+    log::debug!("unveil: path added");
+}
+
+/// Lock the unveil list — no further unveil calls allowed.
+pub fn unveil_lock() {
+    let ret = unsafe { unveil(std::ptr::null(), std::ptr::null()) };
+    if ret != 0 {
+        let err = std::io::Error::last_os_error();
+        log::error!("unveil lock failed: {err}");
+        std::process::exit(1);
+    }
+    log::debug!("unveil locked");
+}
-- 
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