Using utl_http & wallets on 12c: certificate validation failure - oracle

Question

Hope someone can spot what I'm doing wrong as I'm going bald from this.
I have used utl_http & wallets to call https on 11gR1 without much trouble, but our new 12c installation is causing me a lot of grief.
I have tried importing the trusted certificate using both oracle wallet manager, and command line, without any success.
I know that oracle can be picky as to caching the wallet, so I have tried multiple new sessions without any luck.
I have downloaded the three neccessary certificates for *.presstogo.com, Geotrust SSL CA & Geotrust Global CA.
The command-line version of my building the wallet is as follows:
orapki wallet create -wallet /oracle/product/12.0.1/owm/wallets/test1237 -pwd test=1237 -auto_login
orapki wallet add -wallet /oracle/product/12.0.1/owm/wallets/test1237 -trusted_cert -cert "*.presstogo.com" -pwd test=1237
orapki wallet add -wallet /oracle/product/12.0.1/owm/wallets/test1237 -trusted_cert -cert "GeoTrust SSL CA" -pwd test=1237
orapki wallet add -wallet /oracle/product/12.0.1/owm/wallets/test1237 -trusted_cert -cert "Geotrust Global CA" -pwd test=1237
orapki wallet display -wallet /oracle/product/12.0.1/owm/wallets/test1237
Oracle PKI Tool : Version 12.1.0.1
Copyright (c) 2004, 2012, Oracle and/or its affiliates. All rights reserved.
Requested Certificates:
User Certificates:
Trusted Certificates:
Subject: OU=Class 3 Public Primary Certification Authority,O=VeriSign\, Inc.,C=US
Subject: CN=GTE CyberTrust Global Root,OU=GTE CyberTrust Solutions\, Inc.,O=GTE Corporation,C=US
Subject: CN=GeoTrust SSL CA,O=GeoTrust\, Inc.,C=US
Subject: OU=Class 2 Public Primary Certification Authority,O=VeriSign\, Inc.,C=US
Subject: OU=Class 1 Public Primary Certification Authority,O=VeriSign\, Inc.,C=US
Subject: CN=GeoTrust Global CA,O=GeoTrust Inc.,C=US
Subject: CN=*.presstogo.com,OU=IT,O=Press to go AS,L=Oslo,ST=Norway,C=NO,SERIAL_NUM=SJYpOHrRdCDHE8KZ6dRFGMJthOjs7-v3
Ok, lets test this. Login to sqlplus and run the following:
declare
lo_req utl_http.req;
lo_resp utl_http.resp;
begin
utl_http.set_detailed_excp_support ( true );
utl_http.set_wallet ( 'file:/oracle/product/12.0.1/owm/wallets/test1237', 'test=1237');
lo_req := utl_http.begin_request ( 'https://production.presstogo.com/mars/hello' );
lo_resp := utl_http.get_response ( lo_req );
-- A successfull request would have the status code "200".
dbms_output.put_line ( lo_resp.status_code );
utl_http.end_response ( lo_resp );
exception
when others then
utl_http.end_response ( lo_resp );
raise;
end;
DECLARE
*
ERROR at line 1:
ORA-29273: HTTP request failed
ORA-06512: at "SYS.UTL_HTTP", line 1130
ORA-29024: Certificate validation failure
ORA-06512: at line 6
For the record, It is worth noting that the following does work:
declare
lo_req utl_http.req;
lo_resp utl_http.resp;
begin
utl_http.set_wallet ( 'file:/oracle/product/12.0.1/owm/wallets/test1237', 'test=1237');
lo_req := utl_http.begin_request ( 'https://www.google.be' );
lo_resp := utl_http.get_response ( lo_req );
dbms_output.put_line ( lo_resp.status_code );
utl_http.end_response ( lo_resp );
end;
/
Help me Obi-Wan, you're my only hope.

Answer 1

Answering my own question for the benefit of others.
According to Oracle Support only the certificate chain should be imported, not the end site certificate.
In the example I used above, only import the following certificates into the wallet:
Geotrust SSL CA & Geotrust Global CA
Do not import the *.presstogo.com certificate
To quote Oracle support:
The reason that the select is failing in 12c is that 12c does not want
to see the user cert in the wallet as a trusted cert.
This was apparently not an issue in previous versions but removing
that cert from the wallet fixed the issue here.
This contradicts all information I have found online regarding the use of utl_http to connect to Https sites, and confused the hell out of me.
Hopefully this will help others in my situation.