OAM 11.1.2.3 - Bad Oracle Access Manager Request Error After Applying OAM Patch 27373151 + Webgate Patch 27393427 BP 11.1.2.3.180717

After Applying OAM Patch 27373151 + Webgate Patch 27393427 BP 11.1.2.3.180717, when accessing the http resource then it was giving Bad Oracle Access Manager

Like when accessing "http://hostname.domain:7779/index.html" we get following message in the logfile "diagnostics/logs/OHS/ohs1/oblog.log"

2018/10/26@15:29:46.68427       1890    1950    WEB     ERROR   0x0000151F      /ade/aime_ngamac_748106/ngamac/src/palantir/commonlib/src/apache2_req_info.cpp:294     ecid^005UIDZfNp87U8ups^h8iX0000SX00001w  rid^0   "WebGate Error Report"  Message^Unable to process the request due to unexpected error.  ReqReq^GET /public/index.html HTTP/1.1  ReqProto^HTTP/1.1       ReqHost^bdrvl-pd-oid01  ReqStatLine^    ReqStatus^200   ReqRawUri^/public/index.html    ReqUri^/public/index.html       ReqFilename^/orassf/appsso/oid_home/webutil_home/instances/instance3/config/OHS/ohs1/htdocs/public/index.html   ReqPath^        ReqArgs^
2018/10/26@15:30:13.06128       1890    1937    WEB     WARNING 0x00001546      /ade/aime_ngamac_748106/ngamac/src/palantir/webgate2/src/web_gate.cpp:2807      ecid^005UID_Fz_W7U8ups^h8iX0000SX00001y rid^0   "ServerName and/or port mismatch with HostName/Port in the Http HOST request Header."   Host_Port in the Server Config : ^bdrvl-pd-oid01.india.airtel.itm:7779  Host_Port in the Http request : ^xx.xx.xxx.xxx:7779
2018/10/26@15:30:13.06146       1890    1937    WEB     ERROR   0x0000151F      /ade/aime_ngamac_748106/ngamac/src/palantir/commonlib/src/apache2_req_info.cpp:294     ecid^005UID_Fz_W7U8ups^h8iX0000SX00001y  rid^0   "WebGate Error Report"  Message^Unable to process the request due to unexpected error.  ReqReq^GET /public/index.html HTTP/1.1  ReqProto^HTTP/1.1       ReqHost^xx.xx.xxx.xxx   ReqStatLine^    ReqStatus^200   ReqRawUri^/public/index.html    ReqUri^/public/index.html       ReqFilename^/orassf/appsso/oid_home/webutil_home/instances/instance3/config/OHS/ohs1/htdocs/public/index.html   ReqPath^        ReqArgs^
2018/10/26@15:30:16.00229       1890    1937    WEB     WARNING 0x00001546      /ade/aime_ngamac_748106/ngamac/src/palantir/webgate2/src/web_gate.cpp:2807      ecid^005UID_RDY47U8ups^h8iX0000SX00001z rid^0   "ServerName and/or port mismatch with HostName/Port in the Http HOST request Header."   Host_Port in the Server Config : ^bdrvl-pd-oid01.india.airtel.itm:7779  Host_Port in the Http request : ^xx.xx.xxx.xxx:7779



Solution:

The globalHMACFlag user-defined parameter should be true as long as the OAM Server globalHMACEnabled value is set to true.

Also please confirm the following points to make sure everything is confiured correctly:
1-  Make sure that the 11.1.2.3.180717 (BP15) Access Server (patch:28116779) and the 11.1.2.3.180717 (BP11) Webgate (patch:27953548) are applied.  

2- Add User Defined Parameters for webgates involved:
globalHMACFlag=true                    
EnableHostPortValidation=false


3- In oam-config.xml add new property called - globalHMACEnabled
 3.a- Take backup of oam-config.xml file.
 3.b- Stop the OAM Managed server and the AdminServer.
 3.c- Edit oam-config.xml and find the PATH "DeployedComponent > Server > NGAMServer > Profile > oamproxy"
       If the globalHMACEnabled flag is present then toggle from false to true as desired.
        Otherwise if the globalHMACEnabled flag is not present add  - <Setting Name="globalHMACEnabled" Type="xsd:boolean">true</Setting>

Example: 

      </Setting>
        <Setting Name="oamproxy" Type="htf:map">
          <Setting Name="globalHMACEnabled" Type="xsd:boolean">true</Setting>       <<<<<<<<<<<<-------------------------------<<<<<<<<
          <Setting Name="10gCompatibleGetHostIdentifiersSupport" Type="xsd:boolean">false</Setting>
          <Setting Name="SSOOnlyMode" Type="xsd:boolean">false</Setting>
          <Setting Name="NoUniqueSessionsFor10gAgents" Type="xsd:boolean">false</Setting>
          <Setting Name="SharedSecret" Type="xsd:string">350CE18DEB404CAA45A8E07A7ACE508F15D6D8D8CD60045A3CD0158151A16ADD26A1176B3BFBFADC6400B6614F46D013</Setting>
          <Setting Name="secure10gAgentAuthnRequest" Type="xsd:boolean">false</Setting>
          <Setting Name="sslCertModeConfig" Type="htf:map">
            <Setting Name="sslServerCertEntryPwd" Type="xsd:string">Not configured</Setting>
            <Setting Name="sslServerCertEntryAlias" Type="xsd:string"></Setting>
          </Setting>

 3.d- After adding/updating the oam-config.xml file, make sure to increment the config file "Version" value near the top of the file.
 For example, find the below section and increment the value of the version:

<Setting xmlns="http://www.w3.org/2001/XMLSchema" Name="NGAMConfiguration" Type="htf:map">
<Setting Name="Distributor" Type="xsd:string">MapDistributor</Setting>
<Setting Name="DistributorContext" Type="xsd:string">DistributorContext</Setting>
<Setting Name="DistributorMode" Type="xsd:string">MapStore</Setting>
<Setting Name="NotificationLockProvider" Type="xsd:string">ConfigNotificationListeners</Setting>
<Setting Name="ProductRelease" Type="xsd:string">11.1.2.3.0</Setting>
<Setting Name="FilePollingInterval" Type="xsd:integer">30000</Setting>
<Setting Name="NotificationLockWait" Type="xsd:integer">20000</Setting>
<Setting Name="Version" Type="xsd:integer">695</Setting>                         <<<<<<<<<<<<<<<<<<<<<<<-------------------------------<<<<<<<<<<<<<<<<

4- Restart the OAM managed server(s) and the AdminServer.