tor-browser

commit fc74e7d237a19684bd4539645f36bdaacfcb1afe
parent cffdaea8d78c67c470c3acca2b08daf356e8104b
Author: Bob Owen <bobowencode@gmail.com>
Date:   Tue, 11 Nov 2025 09:01:10 +0000

Bug 1997149 - Close KsecDD device handle in windows content process. r=handyman

The handle to KsecDD is opened by cryptbase.dll. It backs calls to
cryptbase!RtlDecryptMemory and cryptbase!RtlEncryptMemory which we do not use.
Controlling the closure via a pref to give a work-around if users hit issues.

Differential Revision: https://phabricator.services.mozilla.com/D271571

Diffstat:
M
modules/libpref/init/StaticPrefList.yaml
 | 
7
+++++++
M
security/sandbox/win/src/sandboxbroker/sandboxBroker.cpp
 | 
6
++++++

2 files changed, 13 insertions(+), 0 deletions(-)
diff --git a/modules/libpref/init/StaticPrefList.yaml b/modules/libpref/init/StaticPrefList.yaml
@@ -17113,6 +17113,13 @@
     type: RelaxedAtomicBool
     value: false
     mirror: always
+
+  # Whether \Device\KsecDD is closed in content process. We are closing this
+  # using a pref to give users a work-around if they have issues.
+-   name: security.sandbox.content.close-ksecdd-handle
+    type: RelaxedAtomicBool
+    value: true
+    mirror: always
 #endif
 
 #if defined(XP_LINUX) && defined(MOZ_SANDBOX)
diff --git a/security/sandbox/win/src/sandboxbroker/sandboxBroker.cpp b/security/sandbox/win/src/sandboxbroker/sandboxBroker.cpp
@@ -1083,6 +1083,12 @@ void SandboxBroker::SetSecurityLevelForContentProcess(int32_t aSandboxLevel,
     config->SetDesktop(sandbox::Desktop::kAlternateWinstation);
   }
 
+  if (StaticPrefs::security_sandbox_content_close_ksecdd_handle()) {
+    result = config->AddKernelObjectToClose(L"File", L"\\Device\\KsecDD");
+    MOZ_RELEASE_ASSERT(sandbox::SBOX_ALL_OK == result,
+                       "AddKernelObjectToClose should never fail.");
+  }
+
   sandbox::MitigationFlags mitigations =
       sandbox::MITIGATION_BOTTOM_UP_ASLR | sandbox::MITIGATION_HEAP_TERMINATE |
       sandbox::MITIGATION_SEHOP | sandbox::MITIGATION_DEP_NO_ATL_THUNK |