1 files changed, 270 insertions, 0 deletions
diff --git a/security/sandbox/test/browser_content_sandbox_syscalls.js b/security/sandbox/test/browser_content_sandbox_syscalls.js
new file mode 100644
index 0000000000..7b95bb061f
--- /dev/null
+++ b/security/sandbox/test/browser_content_sandbox_syscalls.js
@@ -0,0 +1,270 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+/* import-globals-from browser_content_sandbox_utils.js */
+"use strict";
+
+Services.scriptloader.loadSubScript(
+  "chrome://mochitests/content/browser/" +
+    "security/sandbox/test/browser_content_sandbox_utils.js",
+  this
+);
+
+/*
+ * This test is for executing system calls in content processes to validate
+ * that calls that are meant to be blocked by content sandboxing are blocked.
+ * We use the term system calls loosely so that any OS API call such as
+ * fopen could be included.
+ */
+
+// Calls the native execv library function. Include imports so this can be
+// safely serialized and run remotely by ContentTask.spawn.
+function callExec(args) {
+  const { ctypes } = ChromeUtils.import("resource://gre/modules/ctypes.jsm");
+  let { lib, cmd } = args;
+  let libc = ctypes.open(lib);
+  let exec = libc.declare(
+    "execv",
+    ctypes.default_abi,
+    ctypes.int,
+    ctypes.char.ptr
+  );
+  let rv = exec(cmd);
+  libc.close();
+  return rv;
+}
+
+// Calls the native fork syscall.
+function callFork(args) {
+  const { ctypes } = ChromeUtils.import("resource://gre/modules/ctypes.jsm");
+  let { lib } = args;
+  let libc = ctypes.open(lib);
+  let fork = libc.declare("fork", ctypes.default_abi, ctypes.int);
+  let rv = fork();
+  libc.close();
+  return rv;
+}
+
+// Calls the native sysctl syscall.
+function callSysctl(args) {
+  const { ctypes } = ChromeUtils.import("resource://gre/modules/ctypes.jsm");
+  let { lib, name } = args;
+  let libc = ctypes.open(lib);
+  let sysctlbyname = libc.declare(
+    "sysctlbyname",
+    ctypes.default_abi,
+    ctypes.int,
+    ctypes.char.ptr,
+    ctypes.voidptr_t,
+    ctypes.size_t.ptr,
+    ctypes.voidptr_t,
+    ctypes.size_t.ptr
+  );
+  let rv = sysctlbyname(name, null, null, null, null);
+  libc.close();
+  return rv;
+}
+
+// Calls the native open/close syscalls.
+function callOpen(args) {
+  const { ctypes } = ChromeUtils.import("resource://gre/modules/ctypes.jsm");
+  let { lib, path, flags } = args;
+  let libc = ctypes.open(lib);
+  let open = libc.declare(
+    "open",
+    ctypes.default_abi,
+    ctypes.int,
+    ctypes.char.ptr,
+    ctypes.int
+  );
+  let close = libc.declare("close", ctypes.default_abi, ctypes.int, ctypes.int);
+  let fd = open(path, flags);
+  close(fd);
+  libc.close();
+  return fd;
+}
+
+// open syscall flags
+function openWriteCreateFlags() {
+  Assert.ok(isMac() || isLinux());
+  if (isMac()) {
+    let O_WRONLY = 0x001;
+    let O_CREAT = 0x200;
+    return O_WRONLY | O_CREAT;
+  }
+  // Linux
+  let O_WRONLY = 0x01;
+  let O_CREAT = 0x40;
+  return O_WRONLY | O_CREAT;
+}
+
+// Returns the name of the native library needed for native syscalls
+function getOSLib() {
+  switch (Services.appinfo.OS) {
+    case "WINNT":
+      return "kernel32.dll";
+    case "Darwin":
+      return "libc.dylib";
+    case "Linux":
+      return "libc.so.6";
+    default:
+      Assert.ok(false, "Unknown OS");
+      return 0;
+  }
+}
+
+// Returns a harmless command to execute with execv
+function getOSExecCmd() {
+  Assert.ok(!isWin());
+  return "/bin/cat";
+}
+
+// Returns true if the current content sandbox level, passed in
+// the |level| argument, supports syscall sandboxing.
+function areContentSyscallsSandboxed(level) {
+  let syscallsSandboxMinLevel = 0;
+
+  // Set syscallsSandboxMinLevel to the lowest level that has
+  // syscall sandboxing enabled. For now, this varies across
+  // Windows, Mac, Linux, other.
+  switch (Services.appinfo.OS) {
+    case "WINNT":
+      syscallsSandboxMinLevel = 1;
+      break;
+    case "Darwin":
+      syscallsSandboxMinLevel = 1;
+      break;
+    case "Linux":
+      syscallsSandboxMinLevel = 1;
+      break;
+    default:
+      Assert.ok(false, "Unknown OS");
+  }
+
+  return level >= syscallsSandboxMinLevel;
+}
+
+//
+// Drive tests for a single content process.
+//
+// Tests executing OS API calls in the content process. Limited to Mac
+// and Linux calls for now.
+//
+add_task(async function() {
+  // This test is only relevant in e10s
+  if (!gMultiProcessBrowser) {
+    ok(false, "e10s is enabled");
+    info("e10s is not enabled, exiting");
+    return;
+  }
+
+  let level = 0;
+  let prefExists = true;
+
+  // Read the security.sandbox.content.level pref.
+  // If the pref isn't set and we're running on Linux on !isNightly(),
+  // exit without failing. The Linux content sandbox is only enabled
+  // on Nightly at this time.
+  // eslint-disable-next-line mozilla/use-default-preference-values
+  try {
+    level = Services.prefs.getIntPref("security.sandbox.content.level");
+  } catch (e) {
+    prefExists = false;
+  }
+
+  ok(prefExists, "pref security.sandbox.content.level exists");
+  if (!prefExists) {
+    return;
+  }
+
+  info(`security.sandbox.content.level=${level}`);
+  ok(level > 0, "content sandbox is enabled.");
+
+  let areSyscallsSandboxed = areContentSyscallsSandboxed(level);
+
+  // Content sandbox enabled, but level doesn't include syscall sandboxing.
+  ok(areSyscallsSandboxed, "content syscall sandboxing is enabled.");
+  if (!areSyscallsSandboxed) {
+    info("content sandbox level too low for syscall tests, exiting\n");
+    return;
+  }
+
+  let browser = gBrowser.selectedBrowser;
+  let lib = getOSLib();
+
+  // use execv syscall
+  // (causes content process to be killed on Linux)
+  if (isMac()) {
+    // exec something harmless, this should fail
+    let cmd = getOSExecCmd();
+    let rv = await SpecialPowers.spawn(browser, [{ lib, cmd }], callExec);
+    ok(rv == -1, `exec(${cmd}) is not permitted`);
+  }
+
+  // use open syscall
+  if (isLinux() || isMac()) {
+    // open a file for writing in $HOME, this should fail
+    let path = fileInHomeDir().path;
+    let flags = openWriteCreateFlags();
+    let fd = await SpecialPowers.spawn(
+      browser,
+      [{ lib, path, flags }],
+      callOpen
+    );
+    ok(fd < 0, "opening a file for writing in home is not permitted");
+  }
+
+  // use open syscall
+  if (isLinux() || isMac()) {
+    // open a file for writing in the content temp dir, this should fail on
+    // macOS and work on Linux. The open handler in the content process closes
+    // the file for us
+    let path = fileInTempDir().path;
+    let flags = openWriteCreateFlags();
+    let fd = await SpecialPowers.spawn(
+      browser,
+      [{ lib, path, flags }],
+      callOpen
+    );
+    if (isMac()) {
+      ok(
+        fd === -1,
+        "opening a file for writing in content temp is not permitted"
+      );
+    } else {
+      ok(fd >= 0, "opening a file for writing in content temp is permitted");
+    }
+  }
+
+  // use fork syscall
+  if (isLinux() || isMac()) {
+    let rv = await SpecialPowers.spawn(browser, [{ lib }], callFork);
+    ok(rv == -1, "calling fork is not permitted");
+  }
+
+  // On macOS before 10.10 the |sysctl-name| predicate didn't exist for
+  // filtering |sysctl| access. Check the Darwin version before running the
+  // tests (Darwin 14.0.0 is macOS 10.10). This branch can be removed when we
+  // remove support for macOS 10.9.
+  if (isMac() && Services.sysinfo.getProperty("version") >= "14.0.0") {
+    let rv = await SpecialPowers.spawn(
+      browser,
+      [{ lib, name: "kern.boottime" }],
+      callSysctl
+    );
+    ok(rv == -1, "calling sysctl('kern.boottime') is not permitted");
+
+    rv = await SpecialPowers.spawn(
+      browser,
+      [{ lib, name: "net.inet.ip.ttl" }],
+      callSysctl
+    );
+    ok(rv == -1, "calling sysctl('net.inet.ip.ttl') is not permitted");
+
+    rv = await SpecialPowers.spawn(
+      browser,
+      [{ lib, name: "hw.ncpu" }],
+      callSysctl
+    );
+    ok(rv == 0, "calling sysctl('hw.ncpu') is permitted");
+  }
+});