Custodia: use a stronger encryption algo when exporting keys

The Custodia key export handler is using the default's OpenSSL encryption
scheme for PKCS#12.

This represents an issue when performing a migration from CentOS Stream 8 (C8S)
to CentOS Steam 9 (C9S) where the Custodia client running in the new C9S
replica talks to the Custodia server on C8S source server. The later creates an
encrypted PKCS#12 file that contains the cert and the key using the OpenSSL's
default encryption scheme, which is no longer supported on C9S.

This commit enforces a stronger encryption algorigthm by adding following
arguments to the Custodia server handler:

-keypbe AES-256-CBC -certpbe AES-256-CBC -macalg sha384

The new arguments enforce stronger PBEv2 instead of the insecure PBEv1.

Fixes: https://pagure.io/freeipa/issue/9101

Signed-off-by: Francisco Trivino <ftrivino@redhat.com>
Reviewed-By: Christian Heimes <cheimes@redhat.com>
Reviewed-By: Florence Blanc-Renaud <flo@redhat.com>

ipaserver/secrets/handlers/pemfile.py

@@ -31,6 +31,9 @@ def export_key(args, tmpdir):
         '-out', pk12file,
         '-inkey', args.keyfile,
         '-password', 'file:{pk12pwfile}'.format(pk12pwfile=pk12pwfile),
+        '-keypbe', 'AES-256-CBC',
+        '-certpbe', 'AES-256-CBC',
+        '-macalg', 'sha384',
     ])
 
     with open(pk12file, 'rb') as f: