[IOT-1595] Change Policy Engine to us ACE Union behavior.

The current Policy Engine logic is to assess the permissions on the first matching ACE for a
request (matched via Subject and Resource), and respond to the request (Grant or Deny) based on
that ACE.

The new OCF 1.0 behavior specifies that if any ACE allows a request, it should be Granted (so-called "Union" behavior).

To allow consistency we must fix this in 1.2.1.

This patch changes the Policy Engine to keep searching for an ACE that Grants the request,
until either the request is granted, or the end of the ACL is reached.

Change-Id: Idd4e90c37c7e0fcf963105b34b3e82dfde2ccfd2
Signed-off-by: Nathan Heldt-Sheller <nathan.heldt-sheller@intel.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/14701Reviewed-by: Kevin Kane <kkane@microsoft.com>
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Greg Zaverucha <gregz@microsoft.com>

resource/csdk/security/include/internal/policyengine.h

@@ -46,7 +46,6 @@ typedef struct PEContext
     char        resource[MAX_URI_LENGTH];
     OicSecSvrType_t resourceType;
     uint16_t    permission;
-    bool        matchingAclFound;
     bool        amsProcessing;
     SRMAccessResponse_t retVal;
     AmsMgrContext_t     *amsMgrContext;

resource/csdk/security/src/amsmgr.c

@@ -398,7 +398,7 @@ void ProcessAMSRequest(PEContext_t *context)
     OIC_LOG_V(INFO, TAG, "Entering %s", __func__);
     if (NULL != context)
     {
-        if((false == context->matchingAclFound) && (false == context->amsProcessing))
+        if((ACCESS_GRANTED != context->retVal) && (false == context->amsProcessing))
         {
             context->amsProcessing = true;
 

resource/csdk/security/src/policyengine.c

@@ -99,7 +99,6 @@ void SetPolicyEngineState(PEContext_t *context, const PEState_t state)
     memset(&context->subject, 0, sizeof(context->subject));
     memset(&context->resource, 0, sizeof(context->resource));
     context->permission = 0x0;
-    context->matchingAclFound = false;
     context->amsProcessing = false;
     context->retVal = ACCESS_DENIED_POLICY_ENGINE_ERROR;
 
@@ -508,7 +507,6 @@ static void ProcessAccessRequest(PEContext_t *context)
                 if (IsResourceInAce(context->resource, currentAce))
                 {
                     OIC_LOG_V(INFO, TAG, "%s:found matching resource in ACE" ,__func__);
-                    context->matchingAclFound = true;
 
                     // Found the resource, so it's down to valid period & permission.
                     context->retVal = ACCESS_DENIED_INVALID_PERIOD;
@@ -526,7 +524,7 @@ static void ProcessAccessRequest(PEContext_t *context)
             {
                 OIC_LOG_V(INFO, TAG, "%s:no ACL found matching subject for resource %s",__func__, context->resource);
             }
-        } while ((NULL != currentAce) && (false == context->matchingAclFound));
+        } while ((NULL != currentAce) && (ACCESS_GRANTED != context->retVal));
 
         if (IsAccessGranted(context->retVal))
         {
@@ -608,8 +606,9 @@ SRMAccessResponse_t CheckPermission(PEContext_t     *context,
 
             ProcessAccessRequest(context);
 
-            // If matching ACL not found, and subject != wildcard, try wildcard.
-            if ((false == context->matchingAclFound) && \
+            // If access not already granted, and requested subject != wildcard,
+            // try looking for a wildcard ACE that grants access.
+            if ((ACCESS_GRANTED != context->retVal) && \
               (false == IsWildCardSubject(&context->subject)))
             {
                 //Saving subject for Amacl check

resource/csdk/security/unittest/policyengine.cpp

@@ -113,6 +113,5 @@ TEST(PolicyEngineCore, DeInitPolicyEngine)
     DeInitPolicyEngine(&g_peContext);
     EXPECT_EQ(STOPPED, g_peContext.state);
     EXPECT_EQ((uint16_t)0, g_peContext.permission);
-    EXPECT_FALSE(g_peContext.matchingAclFound);
     EXPECT_EQ(ACCESS_DENIED_POLICY_ENGINE_ERROR, g_peContext.retVal);
 }