From 16f994e7944a917fa81c8db11c56c594f4e78b40 Mon Sep 17 00:00:00 2001
From: Alexander Bokovoy <abokovoy@redhat.com>
Date: Tue, 31 Jul 2018 14:59:03 +0300
Subject: [PATCH] Reset mutex callbacks to the default version when finished

If a PKCS11 API caller provided own mutex handling callbacks,
we need to ensure they aren't used after C_Finalize is called
and SoftHSM instance is recycled.

Inability to do so may lead to a situation where callbacks might
be provided by a different dynamically loaded object which is removed
after C_Finalize() call. Thus, callback pointers become invalid and
calling them leads to crashes.

Fixes: https://github.com/opendnssec/SoftHSMv2/issues/408

Signed-off-by: Alexander Bokovoy <abokovoy@redhat.com>
---
 src/lib/SoftHSM.cpp | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/src/lib/SoftHSM.cpp b/src/lib/SoftHSM.cpp
index ee94d3f..e4cc044 100644
--- a/src/lib/SoftHSM.cpp
+++ b/src/lib/SoftHSM.cpp
@@ -314,6 +314,15 @@ static CK_ATTRIBUTE bsAttribute(CK_ATTRIBUTE_TYPE type, const ByteString &value)
 /*****************************************************************************
  Implementation of SoftHSM class specific functions
  *****************************************************************************/
+static void resetMutexFactoryCallbacks()
+{
+	// Reset MutexFactory callbacks to our versions
+	MutexFactory::i()->setCreateMutex(OSCreateMutex);
+	MutexFactory::i()->setDestroyMutex(OSDestroyMutex);
+	MutexFactory::i()->setLockMutex(OSLockMutex);
+	MutexFactory::i()->setUnlockMutex(OSUnlockMutex);
+}
+
 
 // Return the one-and-only instance
 SoftHSM* SoftHSM::i()
@@ -342,6 +351,7 @@ SoftHSM::SoftHSM()
 	slotManager = NULL;
 	sessionManager = NULL;
 	handleManager = NULL;
+	resetMutexFactoryCallbacks();
 }
 
 // Destructor
@@ -352,6 +362,7 @@ SoftHSM::~SoftHSM()
 	if (slotManager != NULL) delete slotManager;
 	if (objectStore != NULL) delete objectStore;
 	if (sessionObjectStore != NULL) delete sessionObjectStore;
+	resetMutexFactoryCallbacks();
 }
 
 /*****************************************************************************
@@ -402,10 +413,7 @@ CK_RV SoftHSM::C_Initialize(CK_VOID_PTR pInitArgs)
 			if (args->flags & CKF_OS_LOCKING_OK)
 			{
 				// Use our own mutex functions.
-				MutexFactory::i()->setCreateMutex(OSCreateMutex);
-				MutexFactory::i()->setDestroyMutex(OSDestroyMutex);
-				MutexFactory::i()->setLockMutex(OSLockMutex);
-				MutexFactory::i()->setUnlockMutex(OSUnlockMutex);
+				resetMutexFactoryCallbacks();
 				MutexFactory::i()->enable();
 			}
 			else
-- 
2.17.1