better idempotency for creating/updating firewall rules during setup. (#8686)

make sure if the Sandbox has to re-initialize with different Sandbox
user SID, it still finds/updates the firewall rule instead of creating a
new one.

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

@@ -0,0 +1,151 @@
+#![cfg(target_os = "windows")]
+
+use anyhow::Result;
+use std::fs::File;
+use std::io::Write;
+
+use windows::core::Interface;
+use windows::core::BSTR;
+use windows::Win32::Foundation::VARIANT_TRUE;
+use windows::Win32::NetworkManagement::WindowsFirewall::INetFwPolicy2;
+use windows::Win32::NetworkManagement::WindowsFirewall::INetFwRule3;
+use windows::Win32::NetworkManagement::WindowsFirewall::NetFwPolicy2;
+use windows::Win32::NetworkManagement::WindowsFirewall::NetFwRule;
+use windows::Win32::NetworkManagement::WindowsFirewall::NET_FW_ACTION_BLOCK;
+use windows::Win32::NetworkManagement::WindowsFirewall::NET_FW_IP_PROTOCOL_ANY;
+use windows::Win32::NetworkManagement::WindowsFirewall::NET_FW_PROFILE2_ALL;
+use windows::Win32::NetworkManagement::WindowsFirewall::NET_FW_RULE_DIR_OUT;
+use windows::Win32::System::Com::CoCreateInstance;
+use windows::Win32::System::Com::CoInitializeEx;
+use windows::Win32::System::Com::CoUninitialize;
+use windows::Win32::System::Com::CLSCTX_INPROC_SERVER;
+use windows::Win32::System::Com::COINIT_APARTMENTTHREADED;
+
+// This is the stable identifier we use to find/update the rule idempotently.
+// It intentionally does not change between installs.
+const OFFLINE_BLOCK_RULE_NAME: &str = "codex_sandbox_offline_block_outbound";
+
+// Friendly text shown in the firewall UI.
+const OFFLINE_BLOCK_RULE_FRIENDLY: &str = "Codex Sandbox Offline - Block Outbound";
+
+pub fn ensure_offline_outbound_block(offline_sid: &str, log: &mut File) -> Result<()> {
+    let local_user_spec = format!("O:LSD:(A;;CC;;;{offline_sid})");
+
+    let hr = unsafe { CoInitializeEx(None, COINIT_APARTMENTTHREADED) };
+    if hr.is_err() {
+        return Err(anyhow::anyhow!("CoInitializeEx failed: {hr:?}"));
+    }
+
+    let result = unsafe {
+        (|| -> Result<()> {
+            let policy: INetFwPolicy2 = CoCreateInstance(&NetFwPolicy2, None, CLSCTX_INPROC_SERVER)
+                .map_err(|e| anyhow::anyhow!("CoCreateInstance NetFwPolicy2: {e:?}"))?;
+            let rules = policy
+                .Rules()
+                .map_err(|e| anyhow::anyhow!("INetFwPolicy2::Rules: {e:?}"))?;
+
+            // Block all outbound IP protocols for this user.
+            ensure_block_rule(
+                &rules,
+                OFFLINE_BLOCK_RULE_NAME,
+                OFFLINE_BLOCK_RULE_FRIENDLY,
+                NET_FW_IP_PROTOCOL_ANY.0,
+                &local_user_spec,
+                offline_sid,
+                log,
+            )?;
+            Ok(())
+        })()
+    };
+
+    unsafe {
+        CoUninitialize();
+    }
+    result
+}
+
+fn ensure_block_rule(
+    rules: &windows::Win32::NetworkManagement::WindowsFirewall::INetFwRules,
+    internal_name: &str,
+    friendly_desc: &str,
+    protocol: i32,
+    local_user_spec: &str,
+    offline_sid: &str,
+    log: &mut File,
+) -> Result<()> {
+    let name = BSTR::from(internal_name);
+    let rule: INetFwRule3 = match unsafe { rules.Item(&name) } {
+        Ok(existing) => existing
+            .cast()
+            .map_err(|e| anyhow::anyhow!("cast existing firewall rule to INetFwRule3: {e:?}"))?,
+        Err(_) => {
+            let new_rule: INetFwRule3 =
+                unsafe { CoCreateInstance(&NetFwRule, None, CLSCTX_INPROC_SERVER) }
+                    .map_err(|e| anyhow::anyhow!("CoCreateInstance NetFwRule: {e:?}"))?;
+            unsafe { new_rule.SetName(&name) }.map_err(|e| anyhow::anyhow!("SetName: {e:?}"))?;
+            // Set all properties before adding the rule so we don't leave half-configured rules.
+            configure_rule(
+                &new_rule,
+                friendly_desc,
+                protocol,
+                local_user_spec,
+                offline_sid,
+            )?;
+            unsafe { rules.Add(&new_rule) }.map_err(|e| anyhow::anyhow!("Rules::Add: {e:?}"))?;
+            new_rule
+        }
+    };
+
+    // Always re-apply fields to keep the setup idempotent.
+    configure_rule(&rule, friendly_desc, protocol, local_user_spec, offline_sid)?;
+
+    log_line(
+        log,
+        &format!(
+            "firewall rule configured name={internal_name} protocol={protocol} LocalUserAuthorizedList={local_user_spec}"
+        ),
+    )?;
+    Ok(())
+}
+
+fn configure_rule(
+    rule: &INetFwRule3,
+    friendly_desc: &str,
+    protocol: i32,
+    local_user_spec: &str,
+    offline_sid: &str,
+) -> Result<()> {
+    unsafe {
+        rule.SetDescription(&BSTR::from(friendly_desc))
+            .map_err(|e| anyhow::anyhow!("SetDescription: {e:?}"))?;
+        rule.SetDirection(NET_FW_RULE_DIR_OUT)
+            .map_err(|e| anyhow::anyhow!("SetDirection: {e:?}"))?;
+        rule.SetAction(NET_FW_ACTION_BLOCK)
+            .map_err(|e| anyhow::anyhow!("SetAction: {e:?}"))?;
+        rule.SetEnabled(VARIANT_TRUE)
+            .map_err(|e| anyhow::anyhow!("SetEnabled: {e:?}"))?;
+        rule.SetProfiles(NET_FW_PROFILE2_ALL.0)
+            .map_err(|e| anyhow::anyhow!("SetProfiles: {e:?}"))?;
+        rule.SetProtocol(protocol)
+            .map_err(|e| anyhow::anyhow!("SetProtocol: {e:?}"))?;
+        rule.SetLocalUserAuthorizedList(&BSTR::from(local_user_spec))
+            .map_err(|e| anyhow::anyhow!("SetLocalUserAuthorizedList: {e:?}"))?;
+    }
+
+    // Read-back verification: ensure we actually wrote the expected SID scope.
+    let actual = unsafe { rule.LocalUserAuthorizedList() }
+        .map_err(|e| anyhow::anyhow!("LocalUserAuthorizedList (read-back): {e:?}"))?;
+    let actual_str = actual.to_string();
+    if !actual_str.contains(offline_sid) {
+        anyhow::bail!(
+            "offline firewall rule user scope mismatch: expected SID {offline_sid}, got {actual_str}"
+        );
+    }
+    Ok(())
+}
+
+fn log_line(log: &mut File, msg: &str) -> Result<()> {
+    let ts = chrono::Utc::now().to_rfc3339();
+    writeln!(log, "[{ts}] {msg}")?;
+    Ok(())
+}