When exporting/importing decoded keys do not use 0 as selection

When decoding 0 as the selection means to decode anything
you get.

However when exporting and then importing the key data 0 as
selection is not meaningful.
So we set it to OSSL_KEYMGMT_SELECT_ALL to make the export/import
function export/import everything that we have decoded.

Fixes #21493

Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Paul Dale <pauli@openssl.org>
Reviewed-by: Todd Short <todd.short@me.com>
(Merged from #21519)

crypto/encode_decode/decoder_pkey.c

@@ -155,7 +155,11 @@ static int decoder_construct_pkey(OSSL_DECODER_INSTANCE *decoder_inst,
 
             import_data.keymgmt = keymgmt;
             import_data.keydata = NULL;
-            import_data.selection = data->selection;
+            if (data->selection == 0)
+                /* import/export functions do not tolerate 0 selection */
+                import_data.selection = OSSL_KEYMGMT_SELECT_ALL;
+            else
+                import_data.selection = data->selection;
 
             /*
              * No need to check for errors here, the value of

providers/implementations/encode_decode/decode_der2key.c

@@ -317,10 +317,14 @@ static int der2key_export_object(void *vctx,
     void *keydata;
 
     if (reference_sz == sizeof(keydata) && export != NULL) {
+        int selection = ctx->selection;
+
+        if (selection == 0)
+            selection = OSSL_KEYMGMT_SELECT_ALL;
         /* The contents of the reference is the address to our object */
         keydata = *(void **)reference;
 
-        return export(keydata, ctx->selection, export_cb, export_cbarg);
+        return export(keydata, selection, export_cb, export_cbarg);
     }
     return 0;
 }

providers/implementations/encode_decode/decode_msblob2key.c

@@ -221,10 +221,14 @@ msblob2key_export_object(void *vctx,
     void *keydata;
 
     if (reference_sz == sizeof(keydata) && export != NULL) {
+        int selection = ctx->selection;
+
+        if (selection == 0)
+            selection = OSSL_KEYMGMT_SELECT_ALL;
         /* The contents of the reference is the address to our object */
         keydata = *(void **)reference;
 
-        return export(keydata, ctx->selection, export_cb, export_cbarg);
+        return export(keydata, selection, export_cb, export_cbarg);
     }
     return 0;
 }

providers/implementations/encode_decode/decode_pvk2key.c

@@ -190,10 +190,14 @@ static int pvk2key_export_object(void *vctx,
     void *keydata;
 
     if (reference_sz == sizeof(keydata) && export != NULL) {
+        int selection = ctx->selection;
+
+        if (selection == 0)
+            selection = OSSL_KEYMGMT_SELECT_ALL;
         /* The contents of the reference is the address to our object */
         keydata = *(void **)reference;
 
-        return export(keydata, ctx->selection, export_cb, export_cbarg);
+        return export(keydata, selection, export_cb, export_cbarg);
     }
     return 0;
 }