1 files changed, 81 insertions, 0 deletions
diff --git a/security/sandbox/linux/SandboxInfo.h b/security/sandbox/linux/SandboxInfo.h
new file mode 100644
index 000000000..1999ac392
--- /dev/null
+++ b/security/sandbox/linux/SandboxInfo.h
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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_SandboxInfo_h
+#define mozilla_SandboxInfo_h
+
+#include "mozilla/Types.h"
+
+// Information on what parts of sandboxing are enabled in this build
+// and/or supported by the system.
+
+namespace mozilla {
+
+class SandboxInfo {
+public:
+  // No need to prevent copying; this is essentially just a const int.
+  SandboxInfo(const SandboxInfo& aOther) : mFlags(aOther.mFlags) { }
+
+  // Flags are checked at initializer time; this returns them.
+  static const SandboxInfo& Get() { return sSingleton; }
+
+  enum Flags {
+    // System call filtering; kernel config option CONFIG_SECCOMP_FILTER.
+    kHasSeccompBPF     = 1 << 0,
+    // Config flag MOZ_CONTENT_SANDBOX; env var MOZ_DISABLE_CONTENT_SANDBOX.
+    kEnabledForContent = 1 << 1,
+    // Config flag MOZ_GMP_SANDBOX; env var MOZ_DISABLE_GMP_SANDBOX.
+    kEnabledForMedia   = 1 << 2,
+    // Env var MOZ_SANDBOX_VERBOSE.
+    kVerbose           = 1 << 3,
+    // Kernel can atomically set system call filtering on entire thread group.
+    kHasSeccompTSync   = 1 << 4,
+    // Can this process create user namespaces? (Man page user_namespaces(7).)
+    kHasUserNamespaces = 1 << 5,
+    // Could a more privileged process have user namespaces, even if we can't?
+    kHasPrivilegedUserNamespaces = 1 << 6,
+    // Env var MOZ_PERMISSIVE_CONTENT_SANDBOX
+    kPermissive        = 1 << 7,
+    // Something is creating threads when we need to still be single-threaded.
+    kUnexpectedThreads = 1 << 8,
+  };
+
+  bool Test(Flags aFlag) const { return (mFlags & aFlag) == aFlag; }
+
+  // Returns true if SetContentProcessSandbox may be called.
+  bool CanSandboxContent() const
+  {
+    return !Test(kEnabledForContent) || Test(kHasSeccompBPF);
+  }
+
+  // Returns true if SetMediaPluginSandbox may be called.
+  bool CanSandboxMedia() const
+  {
+    return !Test(kEnabledForMedia) || Test(kHasSeccompBPF);
+  }
+
+  // For telemetry / crash annotation uses.
+  uint32_t AsInteger() const {
+    return mFlags;
+  }
+
+  // For bug 1222500 or anything else like it: On desktop, this is
+  // called in the parent process at a point when it should still be
+  // single-threaded, to check that the SandboxEarlyInit() call in a
+  // child process is early enough to be single-threaded.  If not,
+  // kUnexpectedThreads is set and affected flags (user namespaces;
+  // possibly others in the future) are cleared.
+  static MOZ_EXPORT void ThreadingCheck();
+private:
+  enum Flags mFlags;
+  // This should be const, but has to allow for ThreadingCheck.
+  static MOZ_EXPORT SandboxInfo sSingleton;
+  SandboxInfo();
+};
+
+} // namespace mozilla
+
+#endif // mozilla_SandboxInfo_h