Add EC Configuration Path patch

docs/README.md

@@ -8,3 +8,4 @@ It does not attempt to handle things such as client certificates or user passwor
  - [`patch_custom_ca_ios.md`](patch_custom_ca_ios.md): The logistics of inserting our custom CA into IOS as well for EC usage.
  - [`patch_base_domain.md`](patch_base_domain.md): Information about what URLs are present within the main DOL and information about patching them.
  - [`patch_ec_title_check.md`](patch_ec_title_check.md): Information about title checks run by EC, and why they were negated.
+ - [`patch_ec_cfg_path.md`](patch_ec_cfg_path.md): An explanation over why the path of `ec.cfg` is changed.

docs/patch_ec_cfg_path.md

@@ -0,0 +1,31 @@
+# Patch: Change EC Configuration Path
+
+## Motivation
+We want to store our own custom credentials for the Wii Shop Channel.
+Between provisioning tickets, identifying users, and permitting download, this is essential to our operation.
+
+However, this file likely contains legitimate identifiers to Nintendo's services. We do not want to have users unable to download purchases of any kind should they wish.
+
+While Nintendo's servers may reprovision credentials as part of syncing, we do not want to risk the possibility of such not occurring for whatever reason.
+
+## Explanation
+The Wii Shop Channel provides a file at `/title/00010002/48414241/data/ec.cfg`. It is utilized by every application that invokes EC - DLC applications, rentals, the Wii Shop, so forth.
+
+This file contains persistent data, such as the provisioned account ID and device token, utilized for authentication. It additionally persists values such as the last sync time.
+
+Other identifiers can be set via `ec.getPersistentValue(name)` or `ec.setPersistentValue(name, value)` within [ECommerceInterface](https://docs.oscwii.org/wii-shop-channel/js/ec/ecommerceinterface).
+
+It is quite important that our changes do not modify or overwrite the user's existing credentials.
+
+We evaluated several solutions:
+  - Not using account identifiers, and accepting any existing identifiers that hit our server.
+    - While most likely possible, it would be nice to not need to do so. Additionally for new clients, credentials we generate will not be accepted by Nintendo later.
+  - Similar to the above, utilizing our own set of identifiers via the exposed JS APIs with custom value names.
+    - This would prove complicated for similar reasons to the above.
+  - Modifying the configuration file's name.
+    - This is the most concise solution, and was chosen.
+
+## Execution
+We replace the only instance of `ec.cfg` with `osc.cfg`, where OSC refers to the Open Shop Channel.
+
+A similar change will be necessary for any DLC titles wishing to take advantage of the Open Shop Channel's backend.

modify_dol.go

@@ -94,4 +94,5 @@ func applyDefaultPatches() {
 	applyPatchSet("Load Custom CA within IOS", LoadCustomCA())
 	applyPatchSet("Change Base Domain", PatchBaseDomain())
 	applyPatchSet("Negate EC Title Check", NegateECTitle)
+	applyPatchSet("Change EC Configuration Path", PatchECCfgPath)
 }

patch_ec_cfg_path.go

@@ -0,0 +1,11 @@
+package main
+
+var PatchECCfgPath = PatchSet{
+	Patch{
+		Name:     "Change EC Configuration Path",
+		AtOffset: 3319968,
+
+		Before: []byte("ec.cfg\x00\x00"),
+		After:  []byte("osc.cfg\x00"),
+	},
+}