windows-sandbox: add resolved permissions helper

codex-rs/windows-sandbox-rs/src/allow.rs

@@ -1,4 +1,5 @@
 use crate::policy::SandboxPolicy;
+use crate::resolved_permissions::ResolvedWindowsSandboxPermissions;
 use dunce::canonicalize;
 use std::collections::HashMap;
 use std::collections::HashSet;
@@ -11,9 +12,19 @@ pub struct AllowDenyPaths {
     pub deny: HashSet<PathBuf>,
 }
 
-pub fn compute_allow_paths(
+pub(crate) fn compute_allow_paths(
     policy: &SandboxPolicy,
-    policy_cwd: &Path,
+    _policy_cwd: &Path,
+    command_cwd: &Path,
+    env_map: &HashMap<String, String>,
+) -> AllowDenyPaths {
+    let permissions =
+        ResolvedWindowsSandboxPermissions::from_legacy_policy_for_cwd(policy, command_cwd);
+    compute_allow_paths_for_permissions(&permissions, command_cwd, env_map)
+}
+
+pub(crate) fn compute_allow_paths_for_permissions(
+    permissions: &ResolvedWindowsSandboxPermissions,
     command_cwd: &Path,
     env_map: &HashMap<String, String>,
 ) -> AllowDenyPaths {
@@ -30,65 +41,15 @@ pub fn compute_allow_paths(
             deny.insert(p);
         }
     };
-    let include_tmp_env_vars = matches!(
-        policy,
-        SandboxPolicy::WorkspaceWrite {
-            exclude_tmpdir_env_var: false,
-            ..
-        }
-    );
-
-    if matches!(policy, SandboxPolicy::WorkspaceWrite { .. }) {
-        let add_writable_root =
-            |root: PathBuf,
-             policy_cwd: &Path,
-             add_allow: &mut dyn FnMut(PathBuf),
-             add_deny: &mut dyn FnMut(PathBuf)| {
-                let candidate = if root.is_absolute() {
-                    root
-                } else {
-                    policy_cwd.join(root)
-                };
-                let canonical = canonicalize(&candidate).unwrap_or(candidate);
-                add_allow(canonical.clone());
-
-                for protected_subdir in [".git", ".codex", ".agents"] {
-                    let protected_entry = canonical.join(protected_subdir);
-                    if protected_entry.exists() {
-                        add_deny(protected_entry);
-                    }
-                }
-            };
-
-        add_writable_root(
-            command_cwd.to_path_buf(),
-            policy_cwd,
-            &mut add_allow_path,
-            &mut add_deny_path,
-        );
 
-        if let SandboxPolicy::WorkspaceWrite { writable_roots, .. } = policy {
-            for root in writable_roots {
-                add_writable_root(
-                    root.clone().into(),
-                    policy_cwd,
-                    &mut add_allow_path,
-                    &mut add_deny_path,
-                );
-            }
-        }
-    }
-    if include_tmp_env_vars {
-        for key in ["TEMP", "TMP"] {
-            if let Some(v) = env_map.get(key) {
-                let abs = PathBuf::from(v);
-                add_allow_path(abs);
-            } else if let Ok(v) = std::env::var(key) {
-                let abs = PathBuf::from(v);
-                add_allow_path(abs);
-            }
+    for writable_root in permissions.writable_roots_for_cwd(command_cwd, env_map) {
+        let canonical = canonicalize(&writable_root.root).unwrap_or(writable_root.root);
+        add_allow_path(canonical);
+        for read_only_subpath in writable_root.read_only_subpaths {
+            add_deny_path(read_only_subpath);
         }
     }
+
     AllowDenyPaths { allow, deny }
 }
 
@@ -146,6 +107,7 @@ mod tests {
         };
         let mut env_map = HashMap::new();
         env_map.insert("TEMP".into(), temp_dir.to_string_lossy().to_string());
+        env_map.insert("TMP".into(), temp_dir.to_string_lossy().to_string());
 
         let paths = compute_allow_paths(&policy, &command_cwd, &command_cwd, &env_map);
 
@@ -162,6 +124,59 @@ mod tests {
         assert!(paths.deny.is_empty(), "no deny paths expected");
     }
 
+    #[test]
+    fn includes_tmp_env_vars_when_requested() {
+        let tmp = TempDir::new().expect("tempdir");
+        let command_cwd = tmp.path().join("workspace");
+        let temp_dir = tmp.path().join("temp");
+        let _ = fs::create_dir_all(&command_cwd);
+        let _ = fs::create_dir_all(&temp_dir);
+
+        let policy = SandboxPolicy::WorkspaceWrite {
+            writable_roots: vec![],
+            network_access: false,
+            exclude_tmpdir_env_var: false,
+            exclude_slash_tmp: false,
+        };
+        let mut env_map = HashMap::new();
+        env_map.insert("TEMP".into(), temp_dir.to_string_lossy().to_string());
+        env_map.insert("TMP".into(), temp_dir.to_string_lossy().to_string());
+
+        let paths = compute_allow_paths(&policy, &command_cwd, &command_cwd, &env_map);
+
+        let expected_allow: HashSet<PathBuf> = [
+            dunce::canonicalize(&command_cwd).unwrap(),
+            dunce::canonicalize(&temp_dir).unwrap(),
+        ]
+        .into_iter()
+        .collect();
+
+        assert_eq!(expected_allow, paths.allow);
+        assert!(paths.deny.is_empty(), "no deny paths expected");
+    }
+
+    #[test]
+    fn ignores_unix_slash_tmp_for_windows_allow_roots() {
+        let tmp = TempDir::new().expect("tempdir");
+        let command_cwd = tmp.path().join("workspace");
+        let _ = fs::create_dir_all(&command_cwd);
+
+        let policy = SandboxPolicy::WorkspaceWrite {
+            writable_roots: vec![],
+            network_access: false,
+            exclude_tmpdir_env_var: true,
+            exclude_slash_tmp: false,
+        };
+
+        let paths = compute_allow_paths(&policy, &command_cwd, &command_cwd, &HashMap::new());
+        let expected_allow: HashSet<PathBuf> = [dunce::canonicalize(&command_cwd).unwrap()]
+            .into_iter()
+            .collect();
+
+        assert_eq!(expected_allow, paths.allow);
+        assert!(paths.deny.is_empty(), "no deny paths expected");
+    }
+
     #[test]
     fn denies_git_dir_inside_writable_root() {
         let tmp = TempDir::new().expect("tempdir");

codex-rs/windows-sandbox-rs/src/lib.rs

@@ -38,6 +38,8 @@ mod policy;
 #[cfg(target_os = "windows")]
 mod process;
 #[cfg(target_os = "windows")]
+mod resolved_permissions;
+#[cfg(target_os = "windows")]
 mod token;
 #[cfg(target_os = "windows")]
 mod wfp;

codex-rs/windows-sandbox-rs/src/resolved_permissions.rs

@@ -0,0 +1,116 @@
+use codex_protocol::permissions::FileSystemPath;
+use codex_protocol::permissions::FileSystemSandboxEntry;
+use codex_protocol::permissions::FileSystemSandboxPolicy;
+use codex_protocol::permissions::NetworkSandboxPolicy;
+use codex_protocol::protocol::SandboxPolicy;
+use codex_utils_absolute_path::AbsolutePathBuf;
+use std::collections::HashMap;
+use std::path::Path;
+use std::path::PathBuf;
+
+/// Windows-local view of the runtime permission profile.
+///
+/// Most Windows sandbox code needs resolved runtime permissions plus a few
+/// Windows-specific path conventions, not the user/config-facing
+/// `PermissionProfile` enum itself.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub(crate) struct ResolvedWindowsSandboxPermissions {
+    file_system: FileSystemSandboxPolicy,
+    network: NetworkSandboxPolicy,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub(crate) struct WindowsWritableRoot {
+    pub(crate) root: PathBuf,
+    pub(crate) read_only_subpaths: Vec<PathBuf>,
+}
+
+impl ResolvedWindowsSandboxPermissions {
+    pub(crate) fn from_legacy_policy(policy: &SandboxPolicy) -> Self {
+        Self {
+            file_system: FileSystemSandboxPolicy::from(policy),
+            network: NetworkSandboxPolicy::from(policy),
+        }
+    }
+
+    pub(crate) fn from_legacy_policy_for_cwd(policy: &SandboxPolicy, cwd: &Path) -> Self {
+        Self {
+            file_system: FileSystemSandboxPolicy::from_legacy_sandbox_policy_for_cwd(policy, cwd),
+            network: NetworkSandboxPolicy::from(policy),
+        }
+    }
+
+    pub(crate) fn should_apply_network_block(&self) -> bool {
+        !self.network.is_enabled()
+    }
+
+    pub(crate) fn writable_roots_for_cwd(
+        &self,
+        cwd: &Path,
+        env_map: &HashMap<String, String>,
+    ) -> Vec<WindowsWritableRoot> {
+        let mut file_system = self.file_system.clone();
+        file_system
+            .entries
+            .retain(|FileSystemSandboxEntry { path, .. }| {
+                !matches!(
+                    path,
+                    FileSystemPath::Special {
+                        value: codex_protocol::permissions::FileSystemSpecialPath::Tmpdir
+                            | codex_protocol::permissions::FileSystemSpecialPath::SlashTmp,
+                    }
+                )
+            });
+
+        let mut roots = file_system
+            .get_writable_roots_with_cwd(cwd)
+            .into_iter()
+            .map(|root| WindowsWritableRoot {
+                root: root.root.into_path_buf(),
+                read_only_subpaths: root
+                    .read_only_subpaths
+                    .into_iter()
+                    .map(AbsolutePathBuf::into_path_buf)
+                    .collect(),
+            })
+            .collect::<Vec<_>>();
+
+        if self.has_writable_tmpdir_entry() {
+            roots.extend(windows_temp_env_roots(env_map).into_iter().map(|root| {
+                WindowsWritableRoot {
+                    root,
+                    read_only_subpaths: Vec::new(),
+                }
+            }));
+        }
+
+        roots
+    }
+
+    fn has_writable_tmpdir_entry(&self) -> bool {
+        self.file_system
+            .entries
+            .iter()
+            .any(|FileSystemSandboxEntry { path, access }| {
+                matches!(
+                    path,
+                    FileSystemPath::Special {
+                        value: codex_protocol::permissions::FileSystemSpecialPath::Tmpdir,
+                    }
+                ) && access.can_write()
+            })
+    }
+}
+
+fn windows_temp_env_roots(env_map: &HashMap<String, String>) -> Vec<PathBuf> {
+    ["TEMP", "TMP"]
+        .into_iter()
+        .filter_map(|key| {
+            env_map
+                .get(key)
+                .map(|value| PathBuf::from(value.as_str()))
+                .or_else(|| std::env::var_os(key).map(PathBuf::from))
+        })
+        .filter(|path| path.is_absolute())
+        .collect()
+}

codex-rs/windows-sandbox-rs/src/setup.rs

@@ -395,14 +395,9 @@ pub(crate) fn gather_write_roots(
     command_cwd: &Path,
     env_map: &HashMap<String, String>,
 ) -> Vec<PathBuf> {
-    let mut roots: Vec<PathBuf> = Vec::new();
-    // Always include the command CWD for workspace-write.
-    if matches!(policy, SandboxPolicy::WorkspaceWrite { .. }) {
-        roots.push(command_cwd.to_path_buf());
-    }
     let AllowDenyPaths { allow, .. } =
         compute_allow_paths(policy, policy_cwd, command_cwd, env_map);
-    roots.extend(allow);
+    let roots: Vec<PathBuf> = allow.into_iter().collect();
     let mut dedup: HashSet<PathBuf> = HashSet::new();
     let mut out: Vec<PathBuf> = Vec::new();
     for r in canonical_existing(&roots) {

codex-rs/windows-sandbox-rs/src/spawn_prep.rs

@@ -19,6 +19,7 @@ use crate::logging::log_start;
 use crate::path_normalization::canonicalize_path;
 use crate::policy::SandboxPolicy;
 use crate::policy::parse_policy;
+use crate::resolved_permissions::ResolvedWindowsSandboxPermissions;
 use crate::sandbox_utils::ensure_codex_home_exists;
 use crate::sandbox_utils::inject_git_safe_directory;
 use crate::setup::effective_write_roots_for_setup;
@@ -73,7 +74,7 @@ pub(crate) struct LegacyAclSids<'a> {
 }
 
 pub(crate) fn should_apply_network_block(policy: &SandboxPolicy) -> bool {
-    !policy.has_full_network_access()
+    ResolvedWindowsSandboxPermissions::from_legacy_policy(policy).should_apply_network_block()
 }
 
 fn prepare_spawn_context_common(