[BEEEP|PM-25164] Prevent memory dumping on renderer on Linux (#16136)

* Implement libmemory_security

* Cleanup and add script

* Remove duplicate build for flatpak

* Rename to process isolation

* Move to desktop native

* Undo changes in gitignore

* Remove after-pack changes

* Run cargo fmt

* Sort deps

* Attempt to fix windows build

* Update apps/desktop/desktop_native/process_isolation/Cargo.toml

Co-authored-by: Daniel García <dani-garcia@users.noreply.github.com>

* Revert "Remove after-pack changes"

This reverts commit c441025587.

* Fix lib process isolation not being included in build

* Fix build

* Attempt to fix build

* Attempt to fix build

* Undo

* Fix library not being included

---------

Co-authored-by: Daniel García <dani-garcia@users.noreply.github.com>

apps/desktop/desktop_native/Cargo.lock

@@ -754,6 +754,22 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "ctor"
+version = "0.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "67773048316103656a637612c4a62477603b777d91d9c62ff2290f9cde178fdb"
+dependencies = [
+ "ctor-proc-macro",
+ "dtor",
+]
+
+[[package]]
+name = "ctor-proc-macro"
+version = "0.0.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e2931af7e13dc045d8e9d26afccc6fa115d64e115c9c84b1166288b46f6782c2"
+
 [[package]]
 name = "ctr"
 version = "0.9.2"
@@ -1049,6 +1065,21 @@ version = "1.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "75b325c5dbd37f80359721ad39aca5a29fb04c89279657cffdda8736d0c0b9d2"
 
+[[package]]
+name = "dtor"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e58a0764cddb55ab28955347b45be00ade43d4d6f3ba4bf3dc354e4ec9432934"
+dependencies = [
+ "dtor-proc-macro",
+]
+
+[[package]]
+name = "dtor-proc-macro"
+version = "0.0.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f678cf4a922c215c63e0de95eb1ff08a958a81d47e485cf9da1e27bf6305cfa5"
+
 [[package]]
 name = "ecdsa"
 version = "0.16.9"
@@ -1886,7 +1917,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "55740c4ae1d8696773c78fdafd5d0e5fe9bc9f1b071c7ba493ba5c413a9184f3"
 dependencies = [
  "bitflags",
- "ctor",
+ "ctor 0.2.9",
  "napi-derive",
  "napi-sys",
  "once_cell",
@@ -2559,6 +2590,15 @@ dependencies = [
  "unicode-ident",
 ]
 
+[[package]]
+name = "process_isolation"
+version = "0.0.0"
+dependencies = [
+ "ctor 0.5.0",
+ "desktop_core",
+ "libc",
+]
+
 [[package]]
 name = "quick-xml"
 version = "0.37.5"

apps/desktop/desktop_native/Cargo.toml

@@ -6,6 +6,7 @@ members = [
     "core",
     "macos_provider",
     "napi",
+    "process_isolation",
     "proxy",
     "windows_plugin_authenticator"
 ]
@@ -27,6 +28,7 @@ byteorder = "=1.5.0"
 bytes = "=1.10.1"
 cbc = "=0.1.2"
 core-foundation = "=0.10.1"
+ctor = "=0.5.0"
 dirs = "=6.0.0"
 ed25519 = "=2.2.3"
 embed_plist = "=1.2.2"

apps/desktop/desktop_native/build.js

@@ -45,6 +45,20 @@ function buildProxyBin(target, release = true) {
     }
 }
 
+function buildProcessIsolation() {
+    if (process.platform !== "linux") {
+        return;
+    }
+
+    child_process.execSync(`cargo build --release`, {
+        stdio: 'inherit',
+        cwd: path.join(__dirname, "process_isolation")
+    });
+
+    console.log("Copying process isolation library to dist folder");
+    fs.copyFileSync(path.join(__dirname, "target", "release", "libprocess_isolation.so"), path.join(__dirname, "dist", `libprocess_isolation.so`));
+}
+
 function installTarget(target) {
     child_process.execSync(`rustup target add ${target}`, { stdio: 'inherit', cwd: __dirname });
 }
@@ -53,6 +67,7 @@ if (!crossPlatform && !target) {
     console.log(`Building native modules in ${mode} mode for the native architecture`);
     buildNapiModule(false, mode === "release");
     buildProxyBin(false, mode === "release");
+    buildProcessIsolation();
     return;
 }
 
@@ -61,6 +76,7 @@ if (target) {
     installTarget(target);
     buildNapiModule(target, mode === "release");
     buildProxyBin(target, mode === "release");
+    buildProcessIsolation();
     return;
 }
 
@@ -78,4 +94,5 @@ platformTargets.forEach(([target, _]) => {
     installTarget(target);
     buildNapiModule(target);
     buildProxyBin(target);
+    buildProcessIsolation();
 });

apps/desktop/desktop_native/process_isolation/Cargo.toml

@@ -0,0 +1,14 @@
+[package]
+name = "process_isolation"
+edition = { workspace = true }
+license = { workspace = true }
+version = { workspace = true }
+publish = { workspace = true }
+
+[lib]
+crate-type = ["cdylib"]
+
+[dependencies]
+ctor = { workspace = true }
+desktop_core = { path = "../core" }
+libc = { workspace = true }

apps/desktop/desktop_native/process_isolation/src/lib.rs

@@ -0,0 +1,46 @@
+#![cfg(target_os = "linux")]
+
+//! This library compiles to a pre-loadable shared object. When preloaded, it
+//! immediately isolates the process using the methods available on the platform.
+//! On Linux, this is PR_SET_DUMPABLE to prevent debuggers from attaching, the env
+//! from being read and the memory from being stolen.
+
+use desktop_core::process_isolation;
+use std::{ffi::c_char, sync::LazyLock};
+
+static ORIGINAL_UNSETENV: LazyLock<unsafe extern "C" fn(*const c_char) -> i32> =
+    LazyLock::new(|| unsafe {
+        std::mem::transmute(libc::dlsym(libc::RTLD_NEXT, c"unsetenv".as_ptr()))
+    });
+
+/// Hooks unsetenv to fix a bug in zypak-wrapper.
+/// Zypak unsets the env in Flatpak as a side-effect, which means that only the top level
+/// processes would be hooked. With this work-around all processes in the tree are hooked
+#[unsafe(no_mangle)]
+unsafe extern "C" fn unsetenv(name: *const c_char) -> i32 {
+    unsafe {
+        let Ok(name_str) = std::ffi::CStr::from_ptr(name).to_str() else {
+            return ORIGINAL_UNSETENV(name);
+        };
+
+        if name_str == "LD_PRELOAD" {
+            // This env variable is provided by the flatpak configuration
+            let ld_preload = std::env::var("PROCESS_ISOLATION_LD_PRELOAD").unwrap_or_default();
+            std::env::set_var("LD_PRELOAD", ld_preload);
+            return 0;
+        }
+
+        ORIGINAL_UNSETENV(name)
+    }
+}
+
+// Hooks the shared object being loaded into the process
+#[ctor::ctor]
+fn preload_init() {
+    let pid = unsafe { libc::getpid() };
+    unsafe {
+        println!("[Process Isolation] Enabling memory security for process {pid}");
+        process_isolation::isolate_process();
+        process_isolation::disable_coredumps();
+    }
+}

apps/desktop/desktop_native/process_isolation/test_isolation.sh

@@ -0,0 +1,40 @@
+#!/bin/bash
+
+# This script tests the memory isolation status of bitwarden-desktop processes. The script will print "isolated"
+# if the memory is not accessible by other processes.
+
+CURRENT_USER=$(whoami)
+
+# Find processes with "bitwarden" in the command
+pids=$(pgrep -f bitwarden)
+
+if [[ -z "$pids" ]]; then
+    echo "No bitwarden processes found."
+    exit 0
+fi
+
+for pid in $pids; do
+    # Get process info: command, PPID, RSS memory
+    read cmd ppid rss <<<$(ps -o comm=,ppid=,rss= -p "$pid")
+
+    # Explicitly skip if the command line does not contain "bitwarden"
+    if ! grep -q "bitwarden" <<<"$cmd"; then
+        continue
+    fi
+
+    # Check ownership of /proc/$pid/environ
+    owner=$(stat -c "%U" /proc/$pid/environ 2>/dev/null)
+
+    if [[ "$owner" == "root" ]]; then
+        status="isolated"
+    elif [[ "$owner" == "$CURRENT_USER" ]]; then
+        status="insecure"
+    else
+        status="unknown-owner:$owner"
+    fi
+
+    # Convert memory to MB 
+    mem_mb=$((rss / 1024))
+
+    echo "PID: $pid | CMD: $cmd | Mem: ${mem_mb}MB | Owner: $owner | Status: $status"
+done